HomeMy WebLinkAboutItem 7b - Adoption of 2025 Urban Water Management Plan, Water Shortage Contingency Plan and 2026 Water Supply and Demand Assessment Item 7b
Department: Utilities
Cost Center: 6001
For Agenda of: 6/16/2026
Placement: Public Hearing
Estimated Time: 30 minutes
FROM: Aaron Floyd, Public Works & Utilities Director
Prepared By: Mychal Boerman, Deputy Director - Water
SUBJECT: ADOPTION OF THE 2025 URBAN WATER MANAGEMENT PLAN, 2025
WATER SHORTAGE CONTINGENCY PLAN, AND RECEIPT AND FILING
OF THE 2026 WATER SUPPLY AND DEMAND ASSESSMENT
RECOMMENDATION
1. Adopt a Resolution entitled “A Resolution of the Council of the City of San Luis Obispo,
California, adopting the 2025 Urban Water Management Plan ”;
2. Adopt a Resolution entitled “A Resolution of the Council of the City of San Luis Obispo,
California, adopting the 2025 Water Shortage Contingency Plan”;
3. Receive and file the City’s 2026 Water Supply and Demand Assessment; and
4. Find that adoption of the 2025 Urban Water Management Plan and 2025 Water
Shortage Contingency Plan is exempt from CEQA pursuant to State CEQA Guidelines
Section 15282(v) and California Water Code Section 10652, and that receiving and
filing the 2026 Water Supply and Demand Assessment is exempt pursuant to CEQA
Guidelines Section 15061(b)(3).
REPORT-IN-BRIEF
This report requests that the City Council hold a public hearing and receive public
comment on the 2025 Urban Water Management Plan and 2025 Water Shortage
Contingency Plan (pursuant to California Water Code Section 10642), adopt the 2025
Urban Water Management Plan, adopt the 2025 Water Shortage Contingency Plan,
receive and file the 2026 Water Supply and Demand Assessment. These documents are
required by the California Water Code and are used to evaluate long-term water supply
reliability, prepare for drought and other water shortage conditions, and assess whether
a water shortage is anticipated during the upcoming fiscal year.
The 2025 Urban Water Management Plan (UWMP) evaluates the City’s water supplies,
projected demands, conservation efforts, water loss, drought risk, and long-term supply
reliability through the 2025-2050 planning horizon. The 2025 Water Shortage
Contingency Plan (WSCP) establishes the City’s staged response framework for
responding to drought, infrastructure failure, water quality degradation, or other water
shortage conditions.
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Item 7b
The 2026 Water Supply and Demand Assessment evaluates projected water supply and
demand conditions on a single-year basis for the upcoming fiscal year covering July 1,
2026 through June 30, 2027.
Results of these planning documents show that the City has sufficient water supplies to
meet projected short-term and long-term demands under the conditions evaluated. The
2025 UWMP demonstrates that the City’s water supply portfolio is sufficient to meet
projected demands under normal-year, single-dry-year, and extended drought conditions
of up to five consecutive years throughout the planning horizon. The 2026 Water Supply
and Demand Assessment similarly shows that projected supplies are sufficient to meet
projected demands during the upcoming fiscal year, including a more granular review of
supply availability on a monthly basis. Based on these analyses, the City does not
anticipate a water shortage or the need to implement Water Shortage Contingency Plan
response actions during the upcoming fiscal year or under the long -term reliability
scenarios evaluated in the UWMP. The City will continue to monitor water supply and
demand, reservoir conditions, infrastructure limitations, water quality conditions, and
regulatory requirements, and may reevaluate supply reliability if actual conditions differ
materially from the assumptions used in these analyses.
Urban Water
Management Plan
(UWMP)
Evaluates the City’s water portfolio
(surface water, recycled water, and
groundwater) against projected
community growth over a 20-to-25-
year planning horizon.
Tests water system reliability by
modeling how supplies hold up during
normal years, single-dry years, and
prolonged, multiple-dry year
sequences.
Measures progress toward the state's
long-term per-capita water use
reduction goals and water-loss
standards.
Documents long-term water supply
strategy, conservation efforts, water
loss reporting, and compliance with
State water supply planning
requirements.
Water Shortage Contingency Plan
(WSCP)
Identifies the City’s six water shortage
stages and the demand reduction actions
that may be implemented during water
shortage conditions.
Outlines conservation, communication and
outreach, and enforcement actions the City
could take to preserve available supplies.
Water Supply and
Demand Assessment
Evaluates the City’s water supply reliability
for the upcoming fiscal year, including
projected monthly supplies and demands.
Determines whether a water shortage is
anticipated and, if needed, identifies the
applicable WSCP shortage stage and
response actions.
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Item 7b
POLICY CONTEXT
The 2025 Urban Water Management Plan and 2025 Water Shortage Contingency Plan
were prepared in accordance with General Plan Water and Wastewater Element Program
A.5.3.3 and California Water Code Sections 10620 through 10645. The 2026 Water
Supply and Demand Assessment was prep ared in accordance with Water and
Wastewater Management Element Program A.5.3.1 and California Water Code Section
10632.1. Preparation of these documents supports Major City Goals for Housing as the
City continues to monitor water supply and demand in supp ort of General Plan build-out
and housing targets identified in the Housing Element.
DISCUSSION
Background
The California Urban Water Management Planning Act is codified in California Water
Code Sections 10610 through 10656 and requires urban water suppliers to adopt (Draft
Resolutions provided as Attachments A and B) and submit an updated Urban Water
Management Plan and Water Shortage Contingency Plan to the Department of Water
Resources every five years. For the 2025 planning cycle, these documents, along with
the 2026 Water Supply and Demand Assessment, must be approved by the City Council
and filed with the Department of Water Resources by July 1, 2026. Urban water suppliers
are defined as agencies that provide water for municipal purposes to more than 3,000
customers or supply more than 3,000 acre-feet of water annually; the City satisfies both
thresholds.
The City adopted its first Urban Water Management Plan in November 1994 and updated
the plan in 2000, 2005, 2010, 2016, and 2021. The City Council adopted the 2020 Urban
Water Management Plan (Resolution 11258) and 2020 Water Shortage Contingency Plan
(Resolution 11259) on June 15,
2021. In addition to regulatory
compliance, adoption of a
compliant Urban Water
Management Plan and Water
Shortage Contingency Plan helps
maintain eligibility for State grants,
low-interest loans, and other
water-related assistance.
In addition to the UWMP and
WSCP, the City is also required to
prepare an Annual Water Supply
and Demand Assessment
pursuant to California Water Code
Section 10632.1. The Annual
Assessment evaluates water
supply and demand conditions for Whale Rock Reservoir
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Item 7b
the upcoming assessment period (July 1, 2026 through June 30, 2027, defined as the
2026-27 fiscal year) and determines whether a shortage is anticipated. If a shortage is
projected, the assessment must identify the applicable shortage level and corresponding
response actions that would be implemented under the City’s Water Shortage
Contingency Plan.
The 2025 Urban Water Management Plan is provided as Attachment C, the 2025 Water
Shortage Contingency Plan is provided as Attachment D, and the 2026 Water Supply and
Demand Assessment is provided
as Attachment E. The discussion
below summarizes the purpose
and key findings of each
document, while the detailed
assumptions, data tables,
calculations, and supporting
information are included in the
attached reports.
2025 Urban Water Management
Plan
The 2025 UWMP is the City’s
primary long-range water supply
planning document. The plan is
prepared every five years and
evaluates whether the City’s water
supplies are sufficient to meet
existing and projected community water demands. The 2025 UWMP reviews a planning
horizon covering 2025 through 2050 and evaluates water supply reliability under normal -
year, single-dry-year, and five-consecutive-dry-year conditions within that timeframe.
The UWMP provides Council, staff, regulatory agencies, and the public with a
comprehensive overview of the City’s water system, water demands, available and
planned supplies, conservation efforts, water loss reporting, drought risk, and long -term
water supply reliability. The plan also documents required State complia nce metrics and
supports coordination between water supply planning, infrastructure planning, and land
use planning. A central purpose of the UWMP is to compare projected water demands
against available and planned supplies over the planning horizon. For t he 2025 UWMP,
projected water demands were developed using current population estimates, land use
assumptions, historical water use trends, and the City’s long-term water demand planning
assumptions. The plan evaluates both potable and non -potable demands, including
residential, commercial, institutional, industrial, landscape irrigation, recycled water, and
water loss components.
The 2025 UWMP also describes the City’s water supply portfolio and how each supply
contributes to long-term reliability. The City’s potable supply portfolio includes Salinas
Reservoir, Whale Rock Reservoir, Nacimiento Reservoir, and planned future
Salinas Reservoir
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Item 7b
groundwater production. The plan also describes the City’s use of recycled water for non-
potable purposes, which offsets potable demand and supports overall water supply
resiliency. The plan evaluates these supplies based on existing water rights, contractual
entitlements, safe annual yield modeling, and current infrastructure conditions.
The 2025 UWMP incorporates updated information since the completion of the 2020
UWMP that is important to the City’s long-term water supply planning. This includes
updated population and demand projections, current conservation trends, recent water
loss audit information, updated safe annual yield modeli ng for Salinas and Whale Rock
reservoirs, the temporary limitation on Nacimiento deliveries resulting from the 2023
storm damage to the Nacimiento transmission pipeline, planned restoration of local
groundwater production, and anticipated recycled water demand growth. These factors
help provide a current and realistic assessment of the City’s water supply reliability
through 2050.
The plan also evaluates drought risk and climate-related uncertainty. Because the City is
highly dependent on surface water sup plies, future changes in precipitation patterns,
runoff, evaporation, water quality, wildfire risk, and drought severity may affect long-term
reliability. The City’s supply reliability analysis is supported by water supply modeling,
including safe annual yield modeling for Salinas and Whale Rock reservoirs, which
incorporates historical hydrologic conditions, reservoir storage, evaporation, and updated
reservoir capacity information to evaluate reliable supply under drought conditions. The
UWMP also considers broader climate-related uncertainty as part of the City’s long-term
planning framework and identifies the City’s diversified portfolio, conservation efforts,
recycled water use, planned groundwater use (up to 700 acre-feet per year), and ongoing
infrastructure planning as important components of long-term resilience.
In addition to evaluating supply reliability, the 2025 UWMP documents the City’s
compliance with State water management requirements. This includes continued
reporting related to Senate Bill X7-7 (Water Conservation Act of 2009) conservation target
compliance, water loss auditing, demand management measures, drought risk
assessment, and water shortage contingency planning. The City’s adopted SB X7-7 water
use target is 117 gallons per capita per day. In 2025, the City’s reported per capita water
use was approximately 87 gallons per capita per day. This performance reflects the City’s
investment in ongoing conservation programs, water efficient development standards,
customer outreach, water-use efficiency incentives, recycled water use, and generally
efficient community water-use patters. Collectively, these elements demonstrate that the
City is meeting applicable State planning requirements while maintaining a long -term
framework for managing water supplies, demands, and reliability.
Based on the analysis completed for the 2025 UWMP, the City’s available and
planned water supplies are sufficient to meet projected demands through 2050 under
the water supply reliability scenarios evaluated in the plan. This includes normal-year,
single-dry-year, and five-consecutive-dry-year conditions. The UWMP therefore
supports the finding that the City has adequate long-term water supply reliability to
account for projected community growth through 2050.
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Item 7b
The State-required UWMP elements and corresponding chapters in the City's 2025
UWMP are shown in Table 1. The City's 2025 UWMP is provided as Attachment C to this
report.
Table 1. Required UWMP Elements and Corresponding 2025 UWMP Chapters
Required Elements
(by Water Code)
City’s 2025 UWMP
Corresponding Chapter
Introduction and Lay Description Chapter 1: Plan Introduction and Overview
Plan Preparation Information Chapter 2: Plan Preparation
System Description Information Chapter 3: Service Area Description
Customer Water Use Information Chapter 4: Water Use Characterization
Conservation Target Compliance Chapter 5: SB X7-7 Baselines, 2020 Targets, and
2025 Reporting
System Supplies Chapter 6: Normal-Year Water Supply
Characterization
Water Service Reliability and
Drought Risk Assessment
Chapter 7: Water Service Reliability and Drought Risk
Assessment
Water Shortage Contingency Plan Chapter 8: Water Shortage Contingency Planning &
Emergency Supply Resiliency
Demand Management Measures Chapter 9: Demand Management Measures
Plan Adoption, Submittal, and
Implementation
Chapter 10: Adoption, Submittal, and Implementation
2025 Water Shortage Contingency Plan
The 2025 WSCP is the City’s action plan for drought, infrastructure disruptions, water
quality issues, catastrophic supply interruptions, or other conditions that may limit
available water supplies. The WSCP establishes a six-stage shortage framework and
identifies the conservation measures, communication tools, enf orcement options, and
operational actions that may be used as shortage conditions become more severe (refer
to Table 2, below). Chapter 8 of the UWMP summarizes the WSCP; however, the WSCP
is being adopted as a separate City Council action. This allows the City Council to amend
or replace the WSCP independently if future regulations, water supply conditions, or City
needs change before the next five-year UWMP update.
As part of the 2025 UWMP update, staff reviewed the Council-adopted 2020 WSCP
against current water supply conditions, updated reliability analysis, current demand
trends, and applicable Water Code requirements. Staff determined that no significant
revisions are necessary at this time. The existing six-stage structure remains
consistent with State requirements and continues to provide a flexible and appropriate
process for responding to varying levels of water shortage.
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Item 7b
Although no significant revisions are proposed, staff recommends that the City Council
readopt the WSCP alongside the 2025 UWMP. Recent guidance from the Department of
Water Resources indicates that readoption is preferred when a supplier has reviewed a
previously adopted WSCP and determined that no changes are needed. In addition to the
opportunity for public review and comment, readoption provides a clear record that the
City reviewed the WSCP as part of the 2025 UWMP update, determined that no significant
revisions are needed at this time, and that the City is reaffirming the WSCP as the City’s
adopted plan for responding to water shortage conditions.
The 2025 WSCP carries forward the response actions from the Council -adopted 2020
WSCP, as summarized in Table 2. The table provides a quick-reference guide for how
the City’s water supply status corresponds to potential City actions. The water supply
status is informed by the City’s Water Projection Model, which is used to estimate how
long available water supplies are expected to sustain the community under the conditions
evaluated. Under normal supply conditions, the City remains in the Monitor status, which
reflects more than five years of available water supply and continued implementation of
ongoing water conservation programs, staffing, budgeting, and public outreach.
If modeled available supplies decline below five years, the WSCP provides a staged
response framework beginning with Watch and progressing through Warning, Alert,
Severe, Extreme, and Critical stages. These stages generally correspond to progressively
lower amounts of available water supply, from less than five years of supply at the Watch
Stage to less than 2.5 years of supply at the Critical Stage. As shortage conditions
become more severe, the City’s response actions also become more restrictive. Early
stages emphasize expanded voluntary conservation, public outreach, rebate programs,
operational changes, and preparation for later stages. Later stages may include
mandatory irrigation limits, water allotments, water offset requirements, restrictions on
new connections, and other measures needed to preserve available supplies for public
health, safety, sanitation, and fire protection.
Table 2 (on the following page) is intended to help the City Council and the public
understand how the WSCP would be implemented by summarizing the relationship
between the City’s water supply status and the types of response actions that may be
considered. The table provides a structured framework for escalating actions as available
supplies decline; however, it does not require the City to apply every listed action
automatically or in the same manner during every shortage. If shortage conditions warrant
action beyond the Monitor Stage, staff would evaluate the severity, duration, timing, and
cause of the shortage, as well as water demand, source availability, infrastructure
conditions, and other relevant factors, and return to the City Council with a recommended
water shortage declaration and associated actions. This process would include
substantial public outreach and communication regarding the conditions prompting the
recommendation, the proposed response actions, and their anticipated effects, as well as
opportunities for public comment and City Council discussion and deliberation before
actions are approved and implemented.
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Item 7b
If required, the City Council would approve, through that declaration and any associated
implementing resolution, ordinance, or other action, the applicable shortage stage and
the specific response actions to be implemented. Following Council direction, City staff
would administer and implement the selected actions consistent with the adopted WSCP,
applicable legal authorities, and the specific circumstances of the shortage.
Table 2. 2025 Water Shortage Contingency Plan
Water Shortage Response Stages Quick Reference Guide
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Item 7b
2026 Water Supply and Demand Assessment
The City’s 2026 Water Supply and Demand Assessment evaluates whether a water
shortage is anticipated during the Assessment Year, defined as July 1, 2026 through June
30, 2027 (2026-27 fiscal year). Unlike the UWMP, which evaluates long-term reliability
through 2050, the Annual Assessment is a near-term planning tool focused on the
upcoming fiscal year. The assessment evaluates projected potable and non -potable
water demands, available water supplies, and monthly supply and demand conditions. If
a shortage were projected, the assessment would identify the applicable WSCP stage
and the response actions that may be necessary to reduce demand and preserve
available supplies.
The Annual Assessment uses the City’s Water Projection Model to estimate how long
available water supplies are expected to sustain the community under the conditions
evaluated. The model considers available supply, projected demand, reservoir storage,
hydrologic conditions, and other relevant factors. The resulting modeled years of available
supply are used to inform the City’s water supply status under the WSCP, which is
organized around stages ranging from Monitor, with more than five years of available
water supply, to Critical, with less than 2.5 years of available water supply.
The Assessment also evaluates supply and demand on a monthly basis, as required by
California Water Code Section 10632.1, to identify whether seasonal shortages may
occur even if annual supplies are sufficient. The City’s monthly analysis shows that
projected available supply exceeds projected demand in every month of the Assessment
Year. Because no annual or monthly shortage is projected, the City does not anticipate
the need to declare a water shortage emergency or implement WSCP response actions
during the 2026-27 Assessment Year.
The City will continue to monitor actual water supply and demand conditions. If actual
conditions differ materially from the assumptions used in the Assessment, the City may
reevaluate supply reliability and implement appropriate actions under the WSCP.
Previous Council or Advisory Body Action
The City Council adopted the 2020 UWMP and 2020 WSCP by Resolutions 11258 and
11259 on June 15, 2021. The City Council received and filed the 2025 Water Supply and
Demand Assessment on May 20, 2025.
Public Engagement
The public has an opportunity to review the Draft UWMP, WSCP, and Water Supply and
For the 2026 Assessment Year, the City’s projected water supplies remain sufficient
to meet expected demands. Based on current water supply availability and demand
forecasts, the Water Projection Model indicates that the City has more than ten years
of water supply available under the modeled conditions. As a result, the City remains
in Monitor status and no WSCP shortage response actions are anticipated during the
Assessment Year.
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Item 7b
Demand Assessment and provide comments prior to and during the public hearing for
these items. As required by the Water Code, public notice of this hearing was posted in
the New Times on May 28th and June 4th, and copies of the documents are available at
the Utilities Branch office at 879 Morro, San Luis Obispo, posted online, and included as
attachments to this agenda report (Attachments C, D, and E).
The City will continue to provide communications regarding current water supply
conditions by posting information and documents on the Utilities website. Additionally,
this information will be incorporated into future public communications material (social
media posts, radio ads, and Farmers Market handouts) and into future water supply
planning documents. A copy of these reports will be sent to the Planning Commission
upon adoption by the City Council and submission to Department of W ater Resources.
CONCURRENCE
The Community Development Department concurs with staff’s recommendation.
ENVIRONMENTAL REVIEW
The adoption of the City’s 2025 Urban Water Management Plan and 2025 Water
Shortage Contingency Plan is statutorily exempt from the requirements of the California
Environmental Quality Act pursuant to State CEQA Guidelines Section 15282(v) and
California Water Code Section 10652. Receiving and filing the 2026 Water Supply and
Demand Assessment is exempt from CEQA pursuant to CEQA Guidelines Section
15061(b)(3), as it can be seen with certainty that the informational assessment has no
possibility of causing a significant effect on the environment.
FISCAL IMPACT
Budgeted: N/A Budget Year: 2025-26
Funding Identified: N/A
Fiscal Analysis:
Funding
Sources
Total Budget
Available
Current
Funding
Request
Remaining
Balance
Annual
Ongoing
Cost
Total $0 $0 $0 $0
The recommended actions do not create a fiscal impact. Adoption of the UWMP and
WSCP and receipt and filing of the Annual Water Supply and Demand Assessment do
not change City staffing levels, create new programs, or authorize additional operating
expenditures. Ongoing water supply planning, conservation, and reporting activities will
continue to be managed within existing Water Fund operating budgets.
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Item 7b
ALTERNATIVES
The City Council could decide not to adopt the 2025 UWMP or 2025 WSCP, or not
to receive and file the 2026 Water Supply and Demand Assessment, and provide
direction to staff on desired modifications. Should Council select this alternative, a
subsequent public hearing would be required and would result in delays beyond the July
1, 2026 due date and may result in noncompliance with the California Water Code and
would require submittal of a request for an extension to the State for consideration.
ATTACHMENTS
A - Draft Resolution adopting the 2025 Urban Water Management Plan
B - Draft Resolution adopting the 2025 Water Shortage Contingency Plan
C - 2025 Urban Water Management Plan
D - 2025 Water Shortage Contingency Plan
E - 2026 Water Supply and Demand Assessment
Page 265 of 476
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R ______
RESOLUTION NO. _____ (2026 SERIES)
A RESOLUTION OF THE CITY COUNCIL OF THE CITY OF SAN LUIS
OBISPO, CALIFORNIA, ADOPTING THE 2025 URBAN WATER
MANAGEMENT PLAN
WHEREAS, the California Legislature enacted Assembly Bill 797 during the 1983-
1984 Regular Session, and as amended subsequently, which mandates that every
supplier providing water for municipal purposes to more than 3,000 customers or
supplying more than 3,000 acre-feet of water annually, prepare an Urban Water
Management Plan; and
WHEREAS, the City is an urban water supplier providing more than 3,000 acre-
feet water annually to approximately 17,000 customers; and
WHEREAS, the City’s Urban Water Management Plan shall be periodically
reviewed at least once every five years, and that the City shall make any amendments or
changes to its plan which are indicated by the review; and
WHEREAS, the 2025 Urban Water Management Plan must be adopted, after
public review and hearing, and filed with the California Department of Water Resources
by July 1, 2026; and
WHEREAS, the City has therefore prepared for public review a draft 2025 Urban
Water Management Plan, and a properly noticed public hearing regarding the Plan was
held by the City Council on June 16, 2026.
NOW, THEREFORE, BE IT RESOLVED by the Council of the City of San Luis
Obispo as follows:
SECTION 1. Adoption of the 2025 Urban Water Management Plan. The 2025
Urban Water Management Plan for the City of San Luis Obispo, consisting of text, tables,
and appendices presented to the City Council on June 16, 2026, on file at the City Clerk’s
Office, is hereby adopted.
SECTION 2. The Public Works and Utilities Director or Assistant Utilities Director
are hereby directed to distribute the 2025 Urban Water Management Plan to the California
Department of Water Resources, the California State Library, and the County of San Luis
Obispo, and make available for public review as prescribed by state law.
SECTION 3. California Environmental Quality Act. The adoption of the City’s 2025
Urban Water Management Plan is hereby determined to be statutorily exempt from the
requirements of the California Environmental Quality Act (CEQA) pursuant to State CEQA
Guidelines Section 15282(v), the preparation of Urban Water Management Plans
pursuant to the provisions of Section 10652 of the Water Code.
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Resolution No. _____ (2026 Series) Page 2
R ______
Upon motion of Council Member ___________, seconded by Council Member
___________, and on the following roll call vote:
AYES:
NOES:
ABSENT:
The foregoing resolution was adopted this _____ day of _______________ 20 26.
___________________________
Mayor Erica A. Stewart
ATTEST:
______________________
Teresa Purrington
City Clerk
APPROVED AS TO FORM:
______________________
J. Christine Dietrick
City Attorney
IN WITNESS WHEREOF, I have hereunto set my hand and affixed the official seal of the
City of San Luis Obispo, California, on ______________________.
___________________________
Teresa Purrington
City Clerk
Page 268 of 476
R ______
RESOLUTION NO. _____ (2026 SERIES)
A RESOLUTION OF THE CITY COUNCIL OF THE CITY OF SAN LUIS
OBISPO, CALIFORNIA, ADOPTING THE 2025 WATER SHORTAGE
CONTINGENCY PLAN
WHEREAS, the California Legislature enacted Assembly Bill 797 during the 1983-
1984 Regular Session, and as amended subsequently, which mandates that every
supplier providing water for municipal purposes to more than 3,000 customers or
supplying more than 3,000 acre-feet of water annually, prepare an Urban Water
Management Plan and separate Water Shortage Contingency Plan; and
WHEREAS, the City is an urban water supplier providing more than 3,000 acre-
feet water annually to approximately 17,000 customers; and
WHEREAS, the 2025 Water Shortage Contingency Plan includes planned
response actions during six water shortage levels to manage and mitigate potential water
supply shortages; and
WHEREAS, the 2025 Water Shortage Contingency Plan includes the written
process the City will use each year to determine its water supply reliability; and
WHEREAS, the 2025 Water Shortage Contingency Plan must be adopted, after
public review and hearing, and submitted to the California Department of Water
Resources by July 1, 2026; and
WHEREAS, the City has therefore prepared for public review a draft 2025 Water
Shortage Contingency Plan, and a properly noticed public hearing regarding the Plan was
held by the City Council on June 16, 2026.
NOW, THEREFORE, BE IT RESOLVED by the Council of the City of San Luis
Obispo as follows:
SECTION 1. Adoption of the 2025 Water Shortage Contingency Plan. The 2025
Water Shortage Contingency Plan for the City of San Luis Obispo, consisting of text,
tables, and appendices presented to the City Council on June 16, 2026, on file at the City
Clerk’s Office, is hereby adopted.
SECTION 2. The Public Works and Utilities Director or Assistant Utilities Director
are hereby directed to distribute the 2025 Water Shortage Contingency Plan to the
California Department of Water Resources, the California State Library, and the County
of San Luis Obispo, and make available for public review as prescribed by state law.
SECTION 3. California Environmental Quality Act. The adoption of the City’s 2025
Water Shortage Contingency Plan is hereby determined to be statutorily exempt from the
Page 269 of 476
Resolution No. _____ (2026 Series) Page 2
R ______
requirements of the California Environmental Quality Act (CEQA) pursuant to Section
10652 of the Water Code.
Upon motion of Council Member ___________, seconded by Council Member
___________, and on the following roll call vote:
AYES:
NOES:
ABSENT:
The foregoing resolution was adopted this _____ day of _______________ 20 26.
___________________________
Mayor Erica A. Stewart
ATTEST:
______________________
Teresa Purrington
City Clerk
APPROVED AS TO FORM:
______________________
J. Christine Dietrick
City Attorney
IN WITNESS WHEREOF, I have hereunto set my hand and affixed the official seal of the
City of San Luis Obispo, California, on ______________________.
___________________________
Teresa Purrington
City Clerk
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2026 Water Supply and Demand Assessment
For the Time Period July 1, 2026 through June 30, 2027
Whale Rock Reservoir
Page 271 of 476
2026 Water Supply and Demand Assessment
2
I. INTRODUCTION
Regulatory Background
California Water Code (CWC §10632.1.)1 directs urban water suppliers (Suppliers) to conduct an Annual
Water Supply and Demand Assessment (Water Supply Assessment) for the purpose of (i) evaluating its
water supply reliability for the current year and one subsequent dry year and (ii) generating and
submitting an Annual Shortage Report by July 1 every year. The procedures for conducting a Water
Supply Assessment shall include the following:
(A) The written decision-making process that an urban water supplier will use each year
to determine its water supply reliability.
(B) The key data inputs and assessment methodology used to evaluate the urban water
supplier’s water supply reliability for the current year and one dry year, including all of
the following:
(i) Current year unconstrained demand2, considering weather, growth, and other
influencing factors, such as policies to manage current supplies to meet demand
objectives in future years, as applicable.
(ii) Current year available supply, considering hydrological and regulatory conditions in
the current year and one dry year. The annual supply and demand assessment may
consider more than one dry year solely at the discretion of the urban water supplier.
(iii) Existing infrastructure capabilities and plausible constraints.
(iv) A defined set of locally applicable evaluation criteria that are consistently relied upon
for each annual water supply and demand assessment.
(v) A description and quantification of each source of water supply.
Assessment Period and Terminology
Consistent with California Water Code section 10632.1, this 2026 Water Supply and Demand Assessment
evaluates the City’s water supply reliability for the period of July 1, 2026, through June 30, 2027. This
period is referred to in this report as the Assessment Year and is evaluated as the subsequent dry year
required for the annual Water Supply and Demand Assessment.
Water use and water supply information from July 1, 2025, through June 30, 2026, is used as supporting
baseline information where appropriate, including to inform projected demands, seasonal use patterns,
and source availability assumptions. This period is referred to in this report as the Current Year. The
Current Year is not the primary assessment period for the 2026 submittal; rather, it provides recent
observed data to support the Assessment Year projections.
Purpose and Assessment Approach
The primary purpose of this Water Supply and Demand Assessment is to evaluate whether the City’s
available water supplies are sufficient to meet anticipated demands during the upcoming Assessment
1 Cal. Water Code §10632.1. can be accessed at:
https://leginfo.legislature.ca.gov/faces/codes_displaySection.xhtml?lawCode=WAT§ionNum=10632
2 Unconstrained demand means the amount of water customers are expected to use if no shortage response actions
or emergency conservation restrictions are applied.
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Year and to determine whether any Water Shortage Contingency Plan (WSCP) response actions may be
needed.
This assessment provides near-term operational reliability analysis that evaluates projected water supply
and demand conditions for the upcoming Assessment Year, rather than long-term water supply adequacy
for General Plan buildout or the full Urban Water Management Plan (UWMP) planning horizon. The City’s
long-term water supply planning is guided by the General Plan and Water and Wastewater Element
(WWE) and is used to evaluate whether the City has adequate supplies to serve planned growth over a
multi-decade period.
Because this assessment focuses on a specific upcoming period, it uses a different methodology than the
City’s long-term water supply planning. Long-term planning relies on General Plan and WWE assumptions
that are intentionally conservative for multi-decade planning. Those assumptions are designed to
evaluate whether the City has adequate water supplies to serve planned growth over the full planning
horizon, not to predict actual water use in a specific upcoming year. For example, long-term demand
planning uses General Plan population assumptions and the City’s 117 gpcd planning value, even though
current potable water use is lower. This provides a planning buffer for future uncertainty related to
population growth, land use changes, customer water use patterns, climate, regulations, infrastructure
conditions, and source availability. This annual assessment uses current and projected near-term
conditions to evaluate whether available supplies are expected to meet anticipated demands during the
Assessment Year. This approach is appropriate because current storage, recent water use, known
infrastructure conditions, and near-term source availability can be evaluated with greater certainty than
long-term buildout conditions.
The City uses its Water Projection Model to support this near-term analysis. The model evaluates the
City’s ability to meet projected demands during the Assessment Year by incorporating current and
projected supply and demand conditions, including but not limited to:
Current reservoir storage;
Anticipated reservoir inflows;
Reservoir evaporation;
Required downstream releases;
Projected customer demand;
Seasonal demand patterns;
Recycled water availability;
Groundwater availability;
Infrastructure or conveyance constraints; and
Applicable dry-year hydrologic assumptions.
Using these inputs, the model estimates how available supplies are expected to change during the
Assessment Year and whether those supplies are sufficient to meet projected demands. The model also
evaluates how current and projected demands affect available supplies over a longer planning period,
accounting for the combined effect of supply availability, customer demand, storage conditions, and
infrastructure limitations. The model then estimates the number of years of available water supply
remaining under the input conditions. The model results help determine whether the City should remain
in normal operations or consider implementation of WSCP response actions based on projected near-
term availability and the City’s estimated years of available supply.
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II. DECISION MAKING PROCESS & ASSESSMENT METHODOLOGY
Annual Decision-Making Process
The City evaluates water supply reliability annually by reviewing current water supply conditions, recent
water use trends, anticipated demands, source-specific availability, infrastructure constraints, and
projected years of available water supply. The annual assessment considers both the volume of water
available from each source and the City’s ability to physically divert, convey, treat, and deliver that water
to customers.
The City uses its Water Projection Model to synthesize these inputs and to evaluate whether projected
supplies are sufficient to meet anticipated demands during the Assessment Year. The model also
evaluates how projected demands affect available supplies over a longer planning period and estimates
the number of years of available water supply remaining under the input conditions. This information
helps determine whether the City is expected to remain in normal operations or whether WSCP response
actions may be needed.
The City’s decision-making process for reviewing water supply availability and demand generally includes
the following steps:
Review current reservoir storage, precipitation, and hydrologic conditions;
Review recent potable and non-potable water use data;
Estimate Assessment Year unconstrained demand using recent demand patterns, current
population estimates, and seasonal use trends;
Quantify available Assessment Year supplies from Nacimiento Reservoir, Salinas Reservoir,
Whale Rock Reservoir, recycled water, and groundwater, as applicable;
Account for infrastructure capabilities and plausible constraints, including temporary or long-
term delivery limitations;
Use the Water Projection Model to evaluate projected supply availability, projected demand,
and estimated years of available water supply;
Compare projected monthly supply and projected monthly unconstrained demand;
Identify any projected monthly or annual shortage;
Determine the applicable shortage level and City WSCP stage, if any; and
Identify planned shortage response actions, if needed.
Key Data Inputs
The City uses locally applicable data inputs to evaluate water supply reliability. These inputs inform the
City’s Water Projection Model and source-specific Assessment Year assumptions. The model uses these
inputs to assess near-term water supply availability, compare projected supply and demand, estimate
the number of years of available water supply remaining, and determine whether projected conditions
may require WSCP response actions.
Assessment Data Inputs and Use Criteria
Data Input Use in Assessment
Reservoir storage and precipitation conditions Used to understand current supply conditions
and near-term operational flexibility.
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Nacimiento Reservoir entitlement and delivery
capacity
Used to estimate available Nacimiento supply
during the Assessment Year.
Salinas and Whale Rock safe annual yield Used to estimate reliable annual supply from the
City’s local surface water reservoirs.
Recycled water production and use Used to estimate non-potable supply, non-
potable demand, and potable demand offsets.
Groundwater project status Used to determine whether groundwater should
be included as an available Assessment Year
supply.
Recent potable water use Used to estimate Assessment Year
unconstrained potable demand.
Customer class demand patterns Used to distribute projected demands by
customer category and month.
Population estimates Used to evaluate per-capita water demand and
inform demand projections.
Infrastructure capabilities and constraints Used to determine whether physically available
water can be conveyed, treated, and delivered.
City WSCP shortage stages Used to determine whether projected supply
conditions would trigger shortage response
actions.
Dry-Year Assessment Assumptions
This assessment evaluates the City’s water supply reliability for the upcoming Assessment Year under a
dry-year planning condition, consistent with California Water Code Section 10632.1. Because the
Assessment Year is in the future, projected demands and available supplies are not based on measured
Assessment Year conditions. Instead, the City uses current-year water use information, historical and
seasonal demand patterns, current reservoir storage, known infrastructure constraints, and dry-year
planning assumptions to estimate whether available supplies would be sufficient during the upcoming
year if dry conditions occur.
The dry-year planning condition is intended to provide a conservative operational test of the City’s near-
term water supply reliability. It is not intended to forecast the most likely hydrologic outcome. Rather, it
evaluates whether the City would have sufficient supplies to meet projected demand during the
Assessment Year under warmer and drier conditions that may increase seasonal water use and reduce
source availability.
Potable and non-potable recycled water are evaluated separately within this report because they are
served by different supplies and have different operational limitations. Potable demands are evaluated
against available potable supplies from Nacimiento Reservoir, Salinas Reservoir, Whale Rock Reservoir,
and groundwater (when available). Recycled water demands are evaluated against non-potable recycled
water supplies available for approved uses and are not assumed to be served by potable water supplies.
Demand Projection Methodology
This assessment uses two different types of demand information: Current Year demand information and
Assessment Year demand projections.
The Current Year is defined as July 1, 2025 through June 30, 2026. Current Year demand information is
based primarily on actual metered water use available up to the time of report preparation. Actual water
use data was available for July 2025 through April 2026, and water use for May and June 2026 was
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estimated. Current Year demand information is used to describe recent water use conditions and to help
inform the Assessment Year projection, but it is not the demand period used for the shortage
determination.
The Assessment Year is defined as a forward-looking dry-year scenario covering the period from July 1,
2026 through June 30, 2027. Because the Assessment Year is in the future, Assessment Year
unconstrained demand is projected rather than measured. Potable and non-potable recycled water
demands are projected separately because they are served by different water supplies and have different
operational limitations.
Assessment Year potable demand was developed by applying a one percent population increase and a
ten percent increase in per-capita water demand to current year water demands. The population
increase is intended to account for expected near-term growth, while the ten percent increase in per-
capita demand is intended to account for higher irrigation and other customer demands that may occur
during abnormally dry conditions. This method provides a reasonable near-term estimate of potable
water demand for an upcoming single dry year.
Assessment Year non-potable recycled water demand was projected separately for the purposes of this
report. Consistent with the City’s recycled water planning assumptions, recycled water demand was
increased by 10 acre-feet per year to reflect anticipated growth in recycled water use over a single year.
Staff also applied a ten percent dry-year adjustment to projected recycled water demand to account for
expected increases in irrigation demand during warmer and drier conditions. This approach recognizes
that recycled water demand is largely seasonal and irrigation-driven, while also maintaining the
distinction between recycled water use and potable water demand.
Supply Projection Methodology
For this report, Assessment Year available supply was determined by source. The City’s primary potable
supplies are Nacimiento Reservoir, Salinas Reservoir, and Whale Rock Reservoir. Recycled water is used
as a non-potable supply for irrigation and construction purposes and offsets potable demand where
recycled water service is available. Groundwater is being developed as a future supplemental potable
supply but is not assumed to be available during the Assessment Year.
Because the Assessment Year is evaluated as a dry-year planning condition, available supplies were
estimated based on source-specific dry-year availability, current reservoir storage, known infrastructure
limitations, and modeled supply reliability where applicable. These assumptions inform the City’s Water
Projection Model, which evaluates whether projected supplies are sufficient to meet projected demands
and estimates the number of years of available water supply remaining under the input conditions.
For long-term water supply planning, the City’s General Plan and WWE include a policy-based reduction
of 500 acre-feet from available supplies to account for future siltation losses at Salinas and Whale Rock
reservoirs. That reduction is appropriate for long-term planning because it helps ensure that
development approved today does not rely on reservoir storage capacity that may be lost to siltation
over time. This annual assessment serves a different purpose because it forecasts near-term supply
reliability for the July 2026 through June 2027 Assessment Year, rather than long-term supply availability
for future development. For that reason, this assessment does not apply the General Plan’s policy-based
500 acre-foot reduction as a separate deduction from Assessment Year available supply. Instead, the City
evaluates the near-term effect of siltation through source-specific modeling and current reservoir
capacity information. The safe annual yield model has been updated with the most recent bathymetric
studies for Salinas Reservoir and Whale Rock Reservoir to ensure that the best available data are used
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for Assessment Year supply availability projections. Based on those model runs, the combined safe
annual yield for Salinas and Whale Rock reservoirs for the Assessment Year is estimated at 4,675 acre-
feet, rather than the 4,910 acre-foot value referenced in the General Plan.
For the Assessment Year, the City assumes the following available supplies:
Nacimiento Reservoir: 1,806 acre-feet, reflecting the temporary delivery limitations associated
with pipeline damage from the 2023 storms;
Salinas and Whale Rock Reservoirs: 4,675 acre-feet, based on Assessment Year model runs using
the City’s safe annual yield model and accounting for the near-term effect of reservoir siltation;
Groundwater: 0 acre-feet, because groundwater is not assumed to be available for potable use
during the Assessment Year;
Recycled water: 1,296 acre-feet of non-potable supply available for use after accounting for
required creek discharge obligations and infrastructure limitations.
Shortage Determination Methodology
For each month of the Assessment Year, projected water demand was compared against projected
available supply. If projected available supply exceeded projected water demand, no shortage was
identified for that month. If projected water demand exceeded projected available water supply, the
shortage volume would be calculated as the difference between demand and supply, and the shortage
percentage would be calculated as the shortage volume divided by unconstrained demand. Any
identified shortage percentage would then be used to identify the applicable State standard shortage
level and corresponding City WSCP stage.
In addition to the monthly supply and demand comparison, the City evaluates whether available water
supplies are forecasted to last five years or longer under the input conditions used in the Water
Projection Model. This longer-term availability assessment is important because the City’s WSCP is
structured to guide shortage response actions when available supplies fall below the City’s established
years-of-supply thresholds. Identifying a potential shortage multiple years in advance is a responsible
water management practice because it provides time for the City to implement phased demand
reduction measures, increase public outreach, adjust operations, preserve reservoir storage, evaluate
supplemental supplies, and avoid more abrupt or disruptive restrictions later. Early identification also
allows the City Council, staff, customers, and regional partners to respond in a measured and coordinated
manner before shortage conditions become more severe. Accordingly, the Water Projection Model
provides both an Assessment Year supply and demand comparison and an estimate of the number of
years of available water supply remaining based on input conditions. The results of the monthly supply
and demand comparison and the years-of-supply analysis are presented in Section V.
III. WATER SUPPLY SOURCE INFORMATION AND INFRASTRUCTURE
CONSTRAINTS
The City relies on multiple water supply sources to meet potable and non-potable demands. Potable
supplies include surface water from Nacimiento Reservoir, Whale Rock Reservoir, and Salinas Reservoir.
Groundwater is being developed as a future supplemental potable supply but is not assumed to be
available during the Assessment Year. Recycled water is used as a non-potable supply for approved uses,
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including landscape irrigation and construction-related uses, and offsets potable demand where recycled
water service is available.
This section summarizes the City’s water supply sources and identifies infrastructure capabilities or
plausible constraints that may affect Assessment Year availability. The source-specific assumptions
described below inform the City’s Water Projection Model and are used to evaluate whether available
supplies are sufficient to meet projected Assessment Year demands.
Nacimiento Reservoir
In 1959, the San Luis Obispo Flood Control and Watershed Protection District (San Luis Obispo District)
entered into an agreement with Monterey County Flood Control and Water Conservation District (now
Monterey County Water Resources Agency) to secure rights to 17,500 acre-feet of water per year (AFY)
from Nacimiento Reservoir. Nacimiento Reservoir is located entirely within San Luis Obispo County,
California (County), and was built by Monterey County Flood Control and Water Conservation District
who continues to control reservoir ownership and operations. Nacimiento Reservoir has a storage
capacity of 377,900 acre-feet and serves the purpose of abating seawater intrusion in the groundwater
aquifers of the Salinas River Valley, while also providing flood protection and groundwater recharge for
the Salinas Valley. Of the San Luis Obispo District’s entitlement, 1,750 AFY have been designated for uses
around the lake, leaving 15,750 AFY for allocation to other areas within the County of San Luis Obispo.
Water is delivered via a 45-mile pipeline from Nacimiento Reservoir to participating agencies and cities.
The “dependable yield” from Nacimiento Reservoir is the contractual amount of water that the City has
rights to from Nacimiento Reservoir. The City’s original contractual amount was 3,380 AFY. Engineering
studies, environmental impact reports, dependable yield analyses, and preliminary design reports were
completed to ensure water needs within the County were met. In 2004, the County solicited interested
agencies who may be interested in participation in the Nacimiento Project. The four initial project
participants included the cities of San Luis Obispo and Paso Robles, the Atascadero Mutual Water
Company, and the Templeton Community Services District. These agencies executed participation
agreements with San Luis Obispo County for entitlements of water which totaled 9,630 acre-feet. In
2004, the County Service Area 10A in Cayucos became a project participant securing 25 AFY. On June 29,
2004, the San Luis Obispo City Council authorized the City’s participation in the Nacimiento Water Project
for the delivery of the original 3,380 AFY of water.
In March 2016, the City Council approved the addition of 2,102 AFY from Nacimiento Reservoir to the
City’s water supply. This addition brought the City’s total Nacimiento Reservoir allocation to 5,482 AFY.
With uncertainty of future climatic conditions, regulation, and aging infrastructure at the City’s other
surface water supplies, the additional supply of Nacimiento water to the City’s portfolio reduces pressure
on the use of water supplies in the Whale Rock and Salinas reservoirs, extending these stored supplies
during future critical water shortages.
During the worst-case drought on record in the region (2012 to 2014), Nacimiento Reservoir remained a
resilient water supply capable of providing a consistent and reliable source of water for San Luis Obispo
County. To confirm the prior analysis with more recent data, the City reviewed rainfall and inflow data
from 2013 which was the driest year on record. Over that year, Nacimiento Reservoir received 35,000
acre-feet of inflow. Though this is significantly below the average inflow into the reservoir, the San Luis
Obispo District’s entitlement could still be met if inflow remained at this level due to the District’s primary
rights.
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Although Nacimiento Reservoir is considered a dependable long-term supply, a large storm event on
January 9, 2023 exposed and damaged the pipeline that delivers water from Nacimiento Reservoir to the
City, disrupting deliveries. In July 2025, the County of San Luis Obispo completed const ruction of a
temporary bypass line that allows the City to receive up to 3.2 million gallons of Nacimiento water per
day while awaiting completion of permanent pipeline repairs. County staff currently estimate that
permanent repairs will restore the City’s full Nacimiento delivery capacity during fall/winter 2027.
For the Assessment Year, the City forecasts 1,806 acre-feet of available Nacimiento supply. This
assumption reflects the temporary delivery limitation associated with the bypass connection and is lower
than the City’s full 5,482 acre-foot annual entitlement. The temporary disruption in Nacimiento deliveries
is accounted for on a monthly basis in the Water Projection Model, and reduced volumes are reflected
throughout the Assessment Year, including no assumed Nacimiento deliveries in February or March
2027.
Whale Rock Reservoir
Whale Rock Reservoir is located on Old Creek Road approximately one-half mile east of the community
of Cayucos, California. The project was planned, designed, and constructed under the supervision of the
California State Department of Water Resources (DWR). Construction took place between October 1958
and April 1961. The reservoir is jointly owned by the City of San Luis Obispo, the California Men’s Colony,
and California Polytechnic State University (Cal Poly). These three agencies form the Whale Rock
Commission which is responsible for operation and administration of the reservoir and associated water
deliveries. Day-to-day operation is provided by the City.
Whale Rock Reservoir is formed by an earthen dam and had the capacity to store an estimated 40,662
acre-feet of water at the time of construction; however, storage capacity has been slightly reduced and
today’s capacity is estimated to be 38,967 acre-feet. The City owns 55.05 percent of the water storage
rights at the reservoir (22,364 acre-feet). The remaining water storage rights are apportioned between
the two State agencies with Cal Poly owning 33.71 percent and the California Men’s Colony owning 11.24
percent. Over the life of the Whale Rock Reservoir and dam, the lake has filled to capacity 14 times, most
recently spilling in the spring of 2024.
The Whale Rock pipeline is approximately 17 miles long, connecting the reservoir to the member
agencies, and terminating at the City's Water Treatment Plant. The design capacity of the pipeline is
18.94 cubic feet per second (approximately 8,500 gallons per minute). The line consists of modified pre-
stressed concrete cylinder pipe at most locations. Whale Rock Reservoir and its associated conveyance
systems are functioning as designed and the City is not aware of any issues that are anticipated to restrict
delivery volumes in the Assessment Year.
Salinas Reservoir
The Salinas Reservoir (also known as Santa Margarita Lake) is located on the upper Salinas River,
approximately nine miles southeast of the community of Santa Margarita. The project was originally built
by the War Department to ensure an adequate water supply for Camp San Luis Obispo, as well as the
City of San Luis Obispo. The dam and appurtenances were declared surplus by the War Department on
April 14, 1947, and the U.S. Army Corps of Engineers assumed responsibility for the facilities. On July 11,
1947, the Corps entered into an agreement with the San Luis Obispo District for the operation and
maintenance of the dam and related facilities. The City has an agreement with the Corps for use of the
reservoir, as well as a water right permit to divert water from the Salinas River for storage within the
reservoir. Immediately following construction, the reservoir had an estimated storage capacity of 24,000
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acre-feet with a surface area of 793 acres, and a drainage area of 112 square miles. In 2023, the District
completed a bathymetric survey of the reservoir to update reservoir capacity calculations. The 2023
update resulted in a reduction of 1,522.56 acre-feet total capacity, reducing the overall capacity to
22,507.75 acre-feet. The decrease in capacity is attributed to siltation of the reservoir, which is estimated
at 46.27 AFY (mean siltation rate over 33 years).
Water is conveyed from Salinas Reservoir through 48,700 feet (9.2 miles) of 24-inch diameter reinforced
concrete pipe to a three-million-gallon forebay at the Santa Margarita booster pump station near the
northerly base of Cuesta Grade adjacent to Highway 101. The pipeline is designed to flow by gravity from
the Reservoir to the forebay when the lake level is above the elevation of 1,267 feet. A booster pump
station at the base of the dam, consisting of two horizontal centrifugal pumps, is capable of maintaining
the rated flow of 12.4 cubic feet per second (approximately 5,565 gallons per minute) when the water
surface elevation falls below 1,267 feet. Salinas Reservoir and its associated conveyance systems are
functioning as designed and the City is not aware of any issues that are anticipated to restrict delivery
volumes in the Assessment Year.
Recycled Water
The City’s Water Resource Recovery Facility (WRRF) produces more than 4,000 acre-feet of disinfected
tertiary-treated effluent each year. A minimum of 1,792 acre-feet is discharged annually to San Luis
Obispo Creek to provide satisfactory habitat and flow volume for fish species, including steelhead trout.
After accounting for required creek discharge, the remaining treated effluent is available as recycled
water for approved non-potable uses. The City currently produces more recycled water than is needed
to meet existing recycled water customer demand, and excess recycled water is discharged to San Luis
Obispo Creek as needed.
Recycled water is evaluated separately from potable water in this assessment because it is available only
for approved non-potable uses and is not available to meet potable water demands. Recycled water
offsets potable demand where recycled water service is available, but its use is limited by customer
demand, distribution system capacity, seasonal irrigation needs, and regulatory discharge requirements.
Recycled water is distributed through the City’s recycled water system and delivered by a pump station
located at the WRRF.
The primary use of recycled water in the City is landscape irrigation, with approximately 75 percent of
recycled water demand occurring from May through October. Recycled water is also used for
construction-related purposes, including dust control and compaction, through annual construction
water permits that the City began issuing in July 2009. The City has four metered hydrant filling stations
located throughout City limits to support these and other approved recycled water uses.
The City has identified a seasonal surplus of recycled water available in excess of required San Luis Obispo
Creek discharge and existing non-potable demands. A recent upgrade to the WRRF will help the City
maximize beneficial use of recycled water, including future consideration of direct or indirect potable
reuse. Until potable reuse is implemented, the City is focused on expanding recycled water use within
City limits to offset potable water demand where feasible.
Groundwater
The City is currently developing groundwater as a future supplemental potable water supply. The City
previously used groundwater for potable purposes but suspended groundwater production in April 2015
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due to water quality concerns associated with tetrachloroethylene (PCE) contamination in the San Luis
Obispo Valley Groundwater Basin.
In July 2020, the City received a nearly $2 million planning-phase grant funded through Proposition 1 to
further evaluate PCE contamination in the basin. That study was completed in April 2023 and provided a
more detailed understanding of the extent of contamination and potential remediation options that
could allow the City to restore groundwater production for potable use. In March 2023, the City received
an additional implementation-phase grant, with current Proposition 1 implementation funding totaling
$7,782,800. The implementation phase includes construction or outfitting of two production wells with
treatment systems. These facilities are intended to provide the City with a supplemental potable water
supply while also cleaning up contaminated groundwater from within the basin. Several new monitoring
wells are also under construction to support evaluation of changing groundwater conditions associated
with renewed groundwater pumping and cleanup operations.
Although groundwater is expected to become an important supplemental potable supply in future years,
it is not assumed to be available during the Assessment Year. The City anticipates completion of the
groundwater pumping wells in spring 2027, with projected groundwater use beginning in July 2027.
Because the Assessment Year covers July 1, 2026 through June 30, 2027, this assessment includes zero
acre-feet of groundwater supply.
Existing Infrastructure Capabilities and Plausible Constraints
The City’s use of multiple water supply sources provides operational flexibility and helps support overall
supply reliability. However, infrastructure limitations, source-specific constraints, water quality
conditions, or emergency events can affect the City’s ability to access, convey, treat, or deliver otherwise
available supplies. These capabilities and constraints are considered as part of the City’s Assessment Year
analysis and are incorporated into the Water Projection Model where applicable.
The most significant infrastructure constraint during the Assessment Year is the temporary limitation on
Nacimiento Reservoir deliveries. Although the City’s contractual Nacimiento allocation is 5,482 acre-feet
per year, the temporary bypass connection limits the volume of Nacimiento water assumed to be
available during the Assessment Year. This assessment assumes 1,806 acre-feet of Nacimiento supply
available during the Assessment Year, with no Nacimiento deliveries assumed in February and March
2027.
The City’s Whale Rock and Salinas reservoir conveyance systems are assumed to be available during the
Assessment Year. The City is not aware of any infrastructure issues with these systems that are
anticipated to restrict delivery volumes during the Assessment Year. However, prolonged disruptions,
pipeline failures, pump station issues, or other infrastructure-related constraints could affect the City’s
ability to rely on these sources in the manner assumed in this assessment.
The City’s Water Treatment Plant is capable of treating water from the City’s surface water supplies and
producing water that meets state and federal drinking water standards. During extreme drought, lower
reservoir levels, increased temperatures, wildfire impacts, or degraded source water quality could create
additional operational challenges, including algae growth, taste and odor concerns, or other treatment
issues. The City has not typically experienced significant water quality limitations that prevent use of its
reservoirs, but these conditions remain plausible constraints during severe drought or other unusual
events.
Recycled water is delivered through the City’s recycled water system and pump station located at the
WRRF. The recycled water pump station does not have backup power during a power outage; however,
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power outages have historically been infrequent, and recycled water is considered a reliable non-potable
supply for purposes of this assessment. Recycled water availability may be affected by customer demand,
distribution system capacity, seasonal irrigation needs, WRRF operations, and regulatory discharge
requirements. Even during periods of extreme drought, the City has produced recycled water in excess
of customer demand, with surplus recycled water available during all months of the year after accounting
for required San Luis Obispo Creek discharge and existing recycled water uses.
Due to the City’s multi-generational investments in a diverse water supply portfolio, temporary
disruptions in any one supply can generally be mitigated through increased use of other available
supplies. This operational flexibility is an important component of the City’s water supply reliability.
However, prolonged disruptions, simultaneous source limitations, extreme drought conditions, major
infrastructure failures, significant water quality changes, or regulatory constraints could result in supply
conditions that differ from those assumed in this assessment. The City will continue to monitor source
availability, infrastructure conditions, water quality, and demand trends throughout the Assessment Year
and may update its reliability analysis if conditions materially change.
IV. CURRENT-YEAR CONDITIONS INFORMING THE ASSESSMENT
Current Year conditions provide recent observed information used to inform the Assessment Year
projection. These conditions include precipitation patterns, reservoir storage levels, recent source use,
potable and non-potable water demand, and per-capita water use. While the Assessment Year analysis
is forward-looking, Current Year information provides an important baseline for evaluating near-term
supply reliability and developing reasonable dry-year demand and supply assumptions.
Current Precipitation and Reservoir Conditions
Precipitation during the Current Year was slightly higher than the average for water years 2013 through
2025. In the City’s watershed areas, precipitation is generally greatest during the winter and early spring
months, from November through April, and is typically limited during the summer months. Because
significant precipitation is not expected before the start of the Assessment Year, current reservoir
storage conditions provide an important indication of near-term supply availability. Current reservoir
storage volumes document that Salinas Reservoir is currently 100 percent full, Nacimiento Reservoir is
currently 61 percent full, and Whale Rock Reservoir is currently 85.6 percent full. These storage
conditions provide the City with substantial operational flexibility heading into the Assessment Year,
particularly when considered together with recent water demand levels.
Table 4-1: Precipitation Measured at the SLO Reservoir Station1
Water Year Accumulation (in inches)
2013 12.36
2014 8.50
2015 11.77
2016 19.02
2017 35.34
2018 13.08
2019 27.10
2020 15.60
2021 11.62
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2022 14.82
2023 53.17
2024 24.37
2025 15.11
2013-2025 Average 20.30
2026 (October-May) 24.14
Notes: Precipitation data measured at the SLO Reservoir – P (749) station can be found at:
https://wr.slocountywater.org/site/?site_id=27&view=51a30d03-3991-46af-9d23-7bc0f56a118f.
Current-Year Water Use by Source
Current Year water use provides recent observed data used to inform the Assessment Year demand
projection and Water Projection Model assumptions. For the Current Year, July 1, 2025 through June 30,
2026, actual water use data were available for July 2025 through April 2026. Water use for May and June
2026 was estimated because complete data were not available at the time this report was prepared.
Based on actual and estimated monthly data, total Current Year City water use is estimated to be 5,092
acre-feet. This includes approximately 4,824 acre-feet of potable water and 268 acre-feet of recycled
water. Potable water use was supplied by Nacimiento Reservoir, Whale Rock Reservoir, and Salinas
Reservoir. Recycled water use served approved non-potable demands and offset potable demand where
recycled water service was available.
The Current Year reflects reduced use of Nacimiento Reservoir due to the Nacimiento pipeline disruption
and temporary bypass limitations. As a result, the City relied more heavily on Whale Rock and Salinas
reservoirs than would typically occur under the City’s long-term strategy of maximizing use of Nacimiento
water when available. This shift in source use is an important consideration for the Assessment Year
because the temporary Nacimiento delivery limitation is expected to continue during the Assessment
Year.
Table 4-2: Current-Year Water Use by Source (July 2025 – June 2026)
Water Supply Source Volume Used (Acre-Feet) Percent of Total Use
Nacimiento Reservoir 1,439 28%
Whale Rock Reservoir 1,837 36%
Salinas Reservoir 1,548 30%
Recycled Water 268 5%
Total City Water Use 5,092 100%
Notes:
1. Water use for May 2026 and June 2026 was estimated as complete data were not available at the time this report
was prepared.
2. Water Delivered to Cal Poly is excluded from City demand because Cal Poly has its own water storage and diversion
rights in Whale Rock Reservoir.
3. Groundwater was not used for potable purposes during the Current Year.
4. Values are in acre-feet and rounded to the nearest whole number; totals may vary slightly due to rounding.
Current-Year Demand and Per-Capita Water Use
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Current Year potable demand is estimated at 4,824 acre-feet. Including recycled water use, total City
water use is estimated at 5,092 acre-feet. Based on these values, estimated per-capita demand, including
recycled water use, is approximately 92 gallons per capita per day. Estimated per-capita potable demand,
excluding recycled water use, is approximately 87 gallons per capita per day.
Current Year water use remains substantially lower than the City’s long-term planning value of 117
gallons per capita per day. This reflects the continued effect of long-term community water conservation
and water use efficiency. The City’s conservation ethic is supported by programs such as water
conservation rebates, school education, community outreach, customer water audits, retrofit-upon-sale
requirements, leak identification and repair, meter testing and replacement, and use of recycled water
for parks and other irrigation demands. These conservation programs are expected to continue in the
upcoming year.
Current Year conditions also demonstrate the value of the City’s multi-source water supply portfolio.
Reduced Nacimiento deliveries were offset through increased use of Whale Rock and Salinas reservoirs.
While this approach was appropriate under current reservoir storage conditions, the City’s long-term
strategy remains to use Nacimiento water when available to reduce pressure on local reservoir storage
and preserve operational flexibility during extended dry periods.
V. ASSESSMENT YEAR SUPPLY AND DEMAND ANALYSIS
Assessment Year Available Potable Supply
The Assessment Year supply and demand analysis evaluates projected potable and non-potable supplies
and demands for July 1, 2026, through June 30, 2027, under a dry-year planning condition. The tables in
this section are not intended to represent actual measured use or actual hydrology for the Assessment
Year. Instead, they compare projected unconstrained demand with projected available supply under the
dry-year scenario used for this annual assessment.
The City’s projected Assessment Year potable supply is 6,481 acre-feet. This includes 1,806 acre-feet
from Nacimiento Reservoir and 4,675 acre-feet from Salinas and Whale Rock reservoirs. Groundwater is
not assumed to be available during the Assessment Year. The General Plan’s separate 500 acre-foot long-
term siltation reduction is not applied in this annual assessment because the Assessment Year safe
annual yield model runs already account for the near-term effect of siltation on available supplies.
Assessment Year availability from Nacimiento Reservoir differs from Current Year records because the
Assessment Year is designed to represent a dry-year planning condition. Under this assumption, the
temporary Nacimiento bypass pipeline is expected to be available for a longer portion of the year than
reflected in the Current Year record because use of the temporary bypass is limited by flow conditions in
the Salinas River. When streamflow is present in the Salinas River, operation of the temporary bypass is
restricted. During dry-year conditions, streamflow is expected to begin later in the year and cease sooner,
allowing the temporary bypass to be used for a greater portion of the Assessment Year.
Table 5-1: Assessment Year Available Potable Supply by Source (July 2026 – June 2027)
Water
Supply
Source
Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun TOTAL
(acre-feet)
Nacimiento
Reservoir 216 216 209 216 209 216 105 0 0 105 105 209 1,806
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Salinas and
Whale
Rock
365 365 365 360 335 335 365 480 480 430 430 365 4,675
Total
Available
Potable
Water
Supply
581 581 574 576 544 551 470 480 480 535 535 574 6,481
Notes:
1. Values are in acre-feet and rounded to the nearest whole number; totals may vary slightly due to rounding.
2. Assessment Year availability from Nacimiento Reservoir varies from Current Year records because the Assessment
Year is designed to represent a dry-year planning condition, which would result in longer availability of the
temporary Nacimiento bypass pipeline.
Assessment Year Available Non-Potable Supply
The City’s projected Assessment Year non-potable recycled water supply 1,296 acre-feet. This volume is
representative of the amount of water that could reasonably be treated and delivered to recycled water
customers within City limits after the City has met its 1.6 MGD creek discharge requirement.
Recycled water availability is determined through model runs using the City’s Recycled Water Delivery
Model. The model allows the City to evaluate recycled water availability based on expected wastewater
influent flows, recycled water production, storage tank capacity, pump station capacity, customer
demand volumes, seasonal demand patterns, and required discharge volume to San Luis Obispo Creek.
For purposes of the 2026 Annual Water Supply and Demand Assessment, the City uses the model to
simulate the amount of recycled water that can reasonably be made available under current system
conditions. This approach reflects the practical limitations of the recycled water system by considering
both available recycled water supply and the infrastructure needed to store and deliver that supply.
Based on current model inputs, recycled water availability is not limited by the total volume of treated
wastewater effluent available for reuse. Instead, the primary limiting factor is the City’s current recycled
water pumping capacity at the Water Resource Recovery Facility. As a result, the recycled water volumes
reported in this assessment reflect the amount of recycled water that can be delivered using exist ing
infrastructure, rather than the total theoretical volume of recycled water that could be available if
additional pumping, storage, or delivery capacity were constructed.
Table 5-2: Assessment Year Available Non-Potable Supply by Source (July 2026 – June 2027)
Water
Supply
Source
Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun TOTAL
(acre-feet)
Recycled
Water 108 108 108 108 108 108 108 108 108 108 108 108 1,296
Notes: Values are in acre-feet and rounded to the nearest whole number; totals may vary slightly due to rounding.
Assessment Year Unconstrained Potable Demand
Assessment Year unconstrained potable demand represents projected customer potable water use for
July 1, 2026, through June 30, 2027. Because this period is in the future, the values shown in Table 5-3
are projections developed from Current Year demand, estimated population growth, and a dry-year
demand adjustment. They are not actual measured demands.
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Assessment Year unconstrained potable demand is projected to be 5,355 acre-feet. This demand volume
reflects a one percent increase in the City’s population in alignment with the City’s General Plan and
observed recent population increases. The Assessment Year demand also reflects a ten percent increase
in per-capita water demand to account for increased irrigation demand and other customer demands
that may occur during abnormally dry conditions.
Table 5-3: Assessment Year Unconstrained Potable Demand by Customer Class (acre-feet)
July 2026 – June 2027
Water Use Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun
TOTAL
(acre-
feet)
Single Family 176 183 171 165 129 129 134 144 155 149 178 172 1,886
Multi-Family 102 104 108 115 102 97 106 115 105 104 113 104 1,275
Commercial 93 92 89 89 75 83 81 87 89 83 87 89 1,037
Industrial 3 3 6 3 2 3 3 3 3 3 3 3 36
Institutional/
Government 19 20 17 15 10 11 11 12 16 13 16 19 180
Landscape
Irrigation 71 68 59 55 27 24 26 29 48 45 59 65 579
Water Loss 30 30 30 30 30 30 30 30 30 30 30 30 362
Total
Potable
Demand
494 500 479 472 377 378 391 420 446 427 487 482 5,355
Notes:
1. Values are in acre-feet and rounded to the nearest whole number for clear presentation; totals may vary slightly
due to rounding.
2. Demand values represent projected unconstrained demand before applying any shortage response actions.
Assessment Year Unconstrained Non-Potable Demand
Assessment Year unconstrained non-potable demand represents projected recycled water demand for
July 1, 2026, through June 30, 2027. Recycled water demand is projected separately from potable
demand because recycled water is available only for approved non-potable uses and is served by
separate recycled water infrastructure.
Assessment Year non-potable recycled water demand is projected to be 306 acre-feet. This demand
consists primarily of landscape irrigation, with additional demand from golf course irrigation,
construction water use, and utility uses. The projection includes the 10 acre-foot annual increase
identified in the City’s recycled water planning assumptions and a ten percent dry-year adjustment to
account for expected increases in irrigation demand during warmer and drier conditions.
Table 5-4: Assessment Year Unconstrained Non-Potable Demand (acre-feet)
July 2026 – June 2027
Water Use Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun TOTAL
(acre-feet)
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Landscape
Irrigation 36.4 38.2 28.9 22.3 9.3 7.0 4.5 8.4 17.1 21.2 24.6 48.8 266.7
Golf Course
Irrigation 4.7 4.3 4.0 2.0 1.3 1.0 1.3 1.3 3.0 3.0 5.0 4.7 35.4
Construction
Use 0.5 0.7 0.3 0.2 0.3 0.1 0.3 0.1 0.1 0.1 0.7 0.3 3.7
Utility Use 0.0 0.0 0.1 0.0 0.0 0.0 0.0 0.1 0.0 0.0 0.0 0.0 0.0
Total Non-
Potable
Demand
41.6 43.2 33.1 24.4 10.9 8.1 6.2 9.8 20.2 24.2 30.3 53.8 305.8
Notes:
1. Values are in acre-feet and rounded to the nearest tenth; totals may vary slightly due to rounding.
2. Demand values represent projected unconstrained demand before applying any shortage response actions.
Assessment Year Potable Supply and Demand Comparison
Projected available potable supply exceeds projected unconstrained potable demand in every month of
the Assessment Year. The projected annual potable surplus is 1,122 acre-feet. Table 5-5 documents
potable water supply availability and demand on a monthly timescale.
Table 5-5: Assessment Year Potable Supply and Demand Comparison (acre-feet)
July 2026 – June 2027
Potable
Water Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun
TOTAL
(acre-
feet)
Anticipated
Unconstrained
Demand (AF)
494 500 479 472 377 379 391 420 446 428 487 482 5355
Anticipated
Total Water
Supply (AF)
581 581 574 576 544 551 470 480 480 535 535 574 6,481
Surplus (AF) 87 81 95 104 167 173 79 60 34 108 48 92 1,126
Percent
Surplus 18 16 20 22 44 46 20 14 8 25 10 19 21%
Water
Shortage
Action
Required (Y/N)
N N N N N N N N N N N N
Notes: Values are in acre-feet and rounded to the nearest whole number; totals may vary slightly due to rounding.
Assessment Year Non-Potable Supply and Demand Comparison
Projected available non-potable recycled water supply exceeds projected non-potable demand in every
month of the Assessment Year. The City estimates recycled water availability using the City’s Recycled
Water Delivery Model, which simulates recycled water availability based on expected wastewater
influent volume, storage tank capacity, pump station capacity, demand volume, seasonal demand
patterns, and required discharge to San Luis Obispo Creek.
For purposes of the 2026 Annual Water Supply and Demand Assessment, the City’s projected non-
potable recycled water availability reflects the amount of recycled water that can reasonably be
delivered with current infrastructure, expected supply volumes, and expected demand conditions. The
City’s projected annual deliverable non-potable recycled water supply is 1,296 acre-feet, compared to
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2026 Water Supply and Demand Assessment
18
projected unconstrained non-potable demand of 306 acre-feet, resulting in a projected annual non-
potable surplus of 990 acre-feet.
Although treated wastewater effluent is available in volumes greater than current recycled water
demand, the City’s ability to make that water available for non-potable use is currently limited by
recycled water pumping capacity at the Water Resource Recovery Facility. As a result, the non-potable
supply volumes shown in this assessment reflect the City’s deliverable recycled water supply under
existing infrastructure conditions, rather than the larger theoretical volume of recycled water that could
be available with future pumping, storage, or distribution system upgrades.
Table 5-6: Assessment Year Non-Potable Supply and Demand Comparison (acre-feet)
July 2026 – June 2027
Non-
Potable
Water
Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun
TOTAL
(acre-
feet)
Anticipated
Unconstraine
d Demand
(AF)
42 43 33 24 11 8 6 10 20 24 30 54 306
Anticipated
Total Water
Supply (AF)
108 108 108 108 108 108 108 108 108 108 108 108 1,296
Surplus (AF) 66 65 75 84 97 100 102 98 88 84 78 54 990
Percent
Surplus 159 150 226 342 891 1234 1642 998 435 347 257 101 324%
Water
Shortage
Action
Required
(Y/N)
N N N N N N N N N N N N
Notes: Values are in acre-feet and rounded to the nearest whole number; totals may vary slightly due to rounding.
Water Shortage Determination
Based on the Assessment Year supply and demand comparison, the City does not anticipate a water
shortage during any month from July 2026 through June 2027. Projected available potable supply
exceeds projected unconstrained potable demand on both an annual and monthly basis. Projected non-
potable recycled water supply also exceeds projected non-potable demand in every month.
In addition to the monthly and annual supply and demand comparison, the City evaluates projected years
of available water supply using the Water Projection Model. The model indicates that, under the input
conditions used for this assessment, the City has more than 10 years of available water supply. Because
no monthly shortage is projected and the City remains above the five-year availability threshold
identified in the WSCP, the City does not plan to implement WSCP response actions during the
Assessment Year.
Although no shortage is projected, the City will continue to monitor water supply and demand conditions
throughout the Assessment Year. If actual conditions differ materially from the assumptions used in this
assessment, the City may reevaluate supply reliability and implement appropriate actions under the
WSCP.
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Conditions that could require reassessment include, but are not limited to:
Further disruption to Nacimiento deliveries;
Unexpected limitations on Salinas or Whale Rock reservoir operations;
Significant water quality changes affecting treatment;
Higher-than-projected customer demand;
Major infrastructure failure;
Regulatory or environmental constraints affecting source availability; or
Extended drought conditions more severe than assumed in this assessment.
If a shortage is identified, the City would implement the applicable WSCP stage and associated response
actions. These actions may include public outreach, increased water use monitoring, restrictions on
discretionary water uses, outdoor irrigation limitations, enforcement actions, and other measures
necessary to reduce demand and extend available supplies.
Monitoring, Communication, Compliance, and Enforcement
The City reads water meters monthly to collect water consumption data for billing, tracking, analysis, and
state reporting. Collection of monthly water use data allows the City to evaluate demand trends, identify
potential changes in customer behavior, and determine whether projected demands remain consistent
with actual use.
Monitoring and reporting are fundamental to water supply planning and shortage management. The City
will continue to monitor observed water use, reservoir storage volumes, source availability,
infrastructure status, water quality, and recycled water availability throughout the Assessment Year. If
conditions differ from the assumptions used in this assessment, the City may update the Water
Projection Model and reevaluate whether WSCP response actions are needed.
The City’s WSCP provides the framework for responding to water shortages by reducing demand,
extending available water supplies, preserving water for public health and safety, and allowing time for
additional rainfall or supplemental supplies to improve supply conditions. If shortage response actions
become necessary, the City’s response may include public outreach, water efficiency measures, outdoor
irrigation restrictions, enforcement actions, and other measures that increase in intensity as shortage
conditions become more severe. The City would monitor the effectiveness of implemented actions by
reviewing monthly water consumption, customer class demand trends, community response,
enforcement activity, and associated revenue and expenditure impacts. Based on these analyses, staff
would recommend program refinements to the City Council as needed.
VI. SUMMARY AND FINDINGS
This 2026 Water Supply and Demand Assessment evaluates the City’s water supply reliability for the
period of July 1, 2026, through June 30, 2027. The assessment uses Current Year water use information,
historical and seasonal demand patterns, current supply conditions, source-specific availability,
infrastructure constraints, and dry-year assumptions to evaluate whether available supplies are sufficient
to meet projected Assessment Year demands.
For potable water, the City’s projected Assessment Year demand is 5,355 acre-feet, and projected
available supply is 6,481 acre-feet, resulting in an estimated potable surplus of 1,126 acre-feet. Projected
available potable supply exceeds projected potable demand in every month of the Assessment Year.
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The Assessment Year potable supply assumptions include restricted Nacimiento Reservoir availability
due to the temporary bypass connection, rather than the City’s full 5,482 acre-foot annual entitlement.
The assessment also includes available supply from Salinas and Whale Rock reservoirs based on
Assessment Year model runs that account for the near-term effect of siltation, and zero acre-feet of
groundwater because groundwater is not assumed to be available during the Assessment Year. The
General Plan’s policy-driven 500 acre-foot long-term siltation reduction is not applied in this annual
assessment because this report evaluates near-term supply reliability for the Assessment Year rather
than long-term supply availability for future development.
For non-potable recycled water, the City’s projected Assessment Year demand is approximately 306 acre-
feet, and projected deliverable supply is 1,296 acre-feet, resulting in an estimated non-potable surplus
of 990 acre-feet. Projected available non-potable recycled water supply exceeds projected non-potable
demand in every month of the Assessment Year. Recycled water is evaluated separately from potable
water because it is available only for approved non-potable uses and is limited by customer demand,
system capacity, seasonal irrigation patterns, WRRF operations, and regulatory discharge requirements.
Based on the monthly supply and demand comparison, the City does not anticipate a water shortage
during the Assessment Year and does not plan to implement WSCP response actions. In addition, the
Water Projection Model indicates that the City has more than 10 years of available water supply under
the input conditions used for this assessment, which is more than the City’s five-year WSCP threshold for
shortage response consideration.
The City will continue to monitor water supply and demand conditions throughout the Assessment Year.
While the City’s diverse water supply portfolio provides reliability and operational flexibility, actual
conditions may differ from the assumptions used in this assessment due to infrastructure disruptions,
extreme drought, water quality changes, regulatory constraints, or higher-than-projected demands. If
conditions materially change, the City is prepared to reassess supply reliability using the Water Projection
Model and implement appropriate response actions under the WSCP, if needed.
Page 290 of 476
DRAFT2025 Urban Water
Management Plan
(PUBLIC REVIEW DRAFT)
This plan was adopted on ________, 2026
pursuant to San Luis Obispo City Council
Resolution No. ________ (2026 series)
San Luis Obispo City Council
Erica A. Stewart, Mayor
Emily Francis, Vice Mayor
Jan Marx
Michelle Shoresman
Michael R. Boswell
Plan Prepared by:
City of San Luis Obispo, Public Works and Utilities Department
Utilities Branch
879 Morro Street
San Luis Obispo, CA 93401
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2
TABLE OF CONTENTS
LIST OF TABLES ............................................................................................................................ 6
ABBREVIATIONS AND ACRONYMS ............................................................................................... 7
EXECUTIVE SUMMARY AND LAY DESCRIPTION ............................................................................. 8
CHAPTER 1: PLAN INTRODUCTION AND OVERVIEW ................................................................... 10
1.1 Urban Water Management Planning Act ...................................................................... 10
1.2 Purpose of the 2025 UWMP ......................................................................................... 10
1.3 General Plan and UWMP Interface .............................................................................. 11
1.4 Organization of the UWMP .......................................................................................... 11
1.5 Relationship to Other Planning Documents ................................................................. 13
CHAPTER 2: PLAN PREPARATION ............................................................................................... 13
2.1 Agency Coordination .................................................................................................. 13
2.2 Public Participation and Plan Adoption ........................................................................ 14
2.3 Plan Implementation .................................................................................................. 14
2.4 Standardized Tables ................................................................................................... 15
2.5 Compliance Checklist ................................................................................................ 15
CHAPTER 3: SERVICE AREA DESCRIPTION.................................................................................. 15
3.1 Introduction ............................................................................................................... 15
3.2 Service Area Overview ................................................................................................ 16
3.3 Climate and Hydrologic Conditions ............................................................................. 16
3.4 Water System Overview .............................................................................................. 17
3.4.1 Water Supply Sources ............................................................................................. 17
3.4.2 Water Treatment Facilities .................................................................................. 18
3.4.3 Potable Water Distribution System ...................................................................... 19
3.4.4 Recycled Water System ...................................................................................... 20
3.5 Existing Population and Demographic Characteristics ................................................. 20
3.6 Future Population Projections ..................................................................................... 21
3.7 Land Use Characteristics and Planning Assumptions .................................................. 22
CHAPTER 4: WATER USE CHARACTERIZATION............................................................................ 23
4.1 Introduction ............................................................................................................... 23
4.2 Demand Sector Definitions ......................................................................................... 24
4.3 Historical Water Demand ............................................................................................ 24
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3
4.4 Current Water Demand ............................................................................................... 25
4.5 Future Water Demand Projections .............................................................................. 26
4.6 Distribution System Water Loss .................................................................................. 28
CHAPTER 5: SB X7-7 BASELINES, 2020 TARGETS, AND 2025 REPORTING .................................... 30
5.1 Introduction and Regulatory Context ........................................................................... 30
5.2 Baseline and Target Summary ..................................................................................... 30
5.3 SB X7-7 Compliance and 2025 Reporting ..................................................................... 30
CHAPTER 6: NORMAL-YEAR WATER SUPPLY CHARACTERIZATION .............................................. 31
6.1 Introduction ............................................................................................................... 31
6.2 Water Supplies ........................................................................................................... 32
6.2.1 Salinas Reservoir .................................................................................................... 32
6.2.2 Whale Rock Reservoir ............................................................................................. 33
6.2.3 Nacimiento Reservoir ............................................................................................. 36
6.2.4 Groundwater .......................................................................................................... 37
6.2.5 Recycled Water ...................................................................................................... 39
6.3 Water Supply Modeling and Yield Assessment ............................................................. 42
6.3.1 Overview of Water Supply Planning Methodology ..................................................... 42
6.3.2 Salinas and Whale Rock Safe Annual Yield Modeling and Reliability .......................... 43
6.3.3 Nacimiento Water Supply Reliability ........................................................................ 45
6.3.4 Groundwater Supply Reliability / Planned Groundwater Supply ................................ 46
6.3.5 Recycled Water Supply Reliability ........................................................................... 47
6.4 Current Year Water Use and Normal-Year Supply Availability ....................................... 48
6.4.1 Current Year Water Supply and Demand .................................................................. 48
6.4.2 Projected Normal-Year Potable Water Supply Volumes ............................................ 48
6.4.3 Projected Normal-Year Non-Potable Water Supply Volumes .................................... 49
6.4.4 Energy Use Information ........................................................................................... 50
6.5 Planned Water Supply Projects and Programs ............................................................. 51
6.6 Climate Change and Water Supply Considerations ...................................................... 52
6.7 Transfers and Exchanges ............................................................................................ 52
CHAPTER 7: WATER SERVICE RELIABILITY AND DROUGHT RISK ASSESSMENT ............................ 53
7.1 Introduction ............................................................................................................... 53
7.2 Basis of Water Service Reliability Assessment ............................................................. 53
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4
7.3 Water Year Type Characterization ............................................................................... 54
7.4 Normal-Year Water Service Reliability ......................................................................... 55
7.5 Single Dry-Year Water Service Reliability ..................................................................... 56
7.6 Multiple Dry-Year Water Service Reliability .................................................................. 56
7.7 Five-Year Drought Risk Assessment ............................................................................ 58
7.8 Reliability Findings and Relationship to the WSCP ....................................................... 59
CHAPTER 8: WATER SHORTAGE CONTINGENCY PLANNING & EMERGENCY SUPPLY RESILIENCY
................................................................................................................................................. 60
8.1 Introduction ............................................................................................................... 60
8.2 Potential Causes of Water Shortage Conditions ........................................................... 60
8.2.1 Seismic Risk Assessment and Mitigation ................................................................. 61
8.3 City Water Shortage Contingency Plan ........................................................................ 62
8.4 Water Shortage Contingency Plan Adoption, Submittal, and Availability ....................... 62
CHAPTER 9: DEMAND MANAGEMENT MEASURES ....................................................................... 63
9.1 Introduction ............................................................................................................... 63
9.2 Water Conservation Program Goals and Objectives ..................................................... 63
9.3 Historical Conservation Efforts ................................................................................... 64
9.4 Demand Management Measure Implementation (2021-2025) ...................................... 64
9.5 Water Waste Prevention Ordinances ........................................................................... 65
9.6 Metering, Billing, and Advanced Metering Infrastructure ............................................... 65
9.7 Conservation Pricing and Water Rate Structure ........................................................... 66
9.8 Public Education, Outreach, and Technical Assistance ................................................ 66
9.9 Programs to Assess and Manage Distribution System Losses ....................................... 66
9.10 Water Conservation Program Coordination and Staffing............................................... 67
9.11 Other Significant Demand Management Measures ...................................................... 67
9.11.1 Recycled Water Use ............................................................................................ 67
9.11.2 Conservation Reviews, Audits, and Customer Support ......................................... 67
9.11.3 Complimentary Devices and Rebate Programs .................................................... 68
9.11.4 MWELO, Landscape Water Budgets, and CII Water Use ....................................... 68
9.12 Planned Demand Management Measures and Performance Tracking ........................... 69
9.13 Relationship to Water Supply Reliability and Shortage Planning .................................... 69
CHAPTER 10: ADOPTION, SUBMITTAL, AND IMPLEMENTATION ................................................... 70
10.1 Introduction ............................................................................................................... 70
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5
10.2 Notice of Plan Preparation and Agency Coordination ................................................... 70
10.3 Public Review Draft and Availability for Public Inspection ............................................. 70
10.4 Public Hearing and Adoption ....................................................................................... 71
10.5 Submittal of Adopted UWMP and WSCP ...................................................................... 71
10.6 Public Availability After Filing ...................................................................................... 72
10.7 Plan Implementation .................................................................................................. 72
10.8 Amendments to the Adopted Plan ............................................................................... 72
APPENDICES ............................................................................................................................. 73
Appendix A – DWR Standardized Submittal Tables ................................................................... 73
Appendix B – DWR UWMP Compliance Checklist..................................................................... 95
Appendix C – Public Notices, Agency Coordination, and Adoption Documentation ................... 99
Appendix D – Water Loss Audit Documentation ..................................................................... 103
Appendix E – Safe Annual Yield Technical Memorandum ........................................................ 104
Appendix F – Annual Water Supply and Demand Assessments ............................................... 105
Appendix G – Seismic Risk / Hazard Mitigation Plan Reference ............................................... 106
Appendix H – Water Shortage Contingency Plan .................................................................... 108
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6
LIST OF TABLES
Table 3-1: San Luis Obispo Climate ........................................................................................................... 16
Table 3-2: Top Employers ........................................................................................................................... 21
Table 3-3: City Population Projections ........................................................................................................ 22
Table 4-1: 2025 Potable Water Use by Sector ........................................................................................... 25
Table 4-2: Projected Future Potable Water Demand by Year .................................................................... 27
Table 4-3: Projected Future Non-Potable Water Demand by Sector.......................................................... 27
Table 4-4: Common Water Loss & Unbilled Consumption Types .............................................................. 28
Table 4-5: Water Loss Audit Data and Results ........................................................................................... 29
Table 5-1: SB X7-7 Baseline and Target Summary .................................................................................... 30
Table 6-1: Whale Rock Reservoir Downstream Entitlements ..................................................................... 35
Table 6-2: Surface Water Reservoir Characteristics .................................................................................. 37
Table 6-3: Groundwater Pumping Volumes ................................................................................................ 38
Table 6-4: Treated Wastewater Uses within City in FY 2025 (in acre-feet) ................................................ 40
Table 6-5: FY 2025 Recycled Water Demand by Customer Class............................................................. 41
Table 6-6: FY 2025 Actual Water Supply Use by Source ........................................................................... 48
Table 6-7: Projected Normal-Year Potable Water Supply Volumes (in acre-feet) ...................................... 49
Table 6-8: Projected Normal-Year Non-Potable Water Supply Volumes (in acre-feet) .............................. 50
Table 6-9: FY 2025 Potable Water-Related Electricity Use ........................................................................ 51
Table 7-1: Normal-Year Potable Water Reliability ...................................................................................... 55
Table 7-2: Normal-Year Non-Potable Reliability ......................................................................................... 55
Table 7-3: Single Dry-Year Potable Water Reliability ................................................................................. 56
Table 7-4: Single Dry-Year Non-Potable Water Reliability ......................................................................... 56
Table 7-5: Multiple Dry-Year Potable Water Reliability ............................................................................... 57
Table 7-6: Multiple Dry-Year Non-Potable Water Reliability ....................................................................... 57
Table 7-7: Five-Year Drought Risk Assessment - Potable Water............................................................... 59
Table 7-8: Five-Year Drought Risk Assessment - Non-Potable Water ....................................................... 59
Table 9-1: Demand Management Measure Implementation Summary (2021-2025) ................................. 65
Table 10-1: Required Post-Adoption Submittals ......................................................................................... 71
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ABBREVIATIONS AND ACRONYMS
ADU - Accessory Dwelling Unit
AF - Acre-Foot or Acre-Feet
AFY (or afy) - Acre-Feet per Year
AMI - Advanced Metering Infrastructure
AWWA - American Water Works Association
CALGreen - California Green Building Standards Code
CAWO - Cayucos Area Water Organization
CII - Commercial, Industrial, and Institutional water use sectors
CIMIS - California Irrigation Management Information System
CWC - California Water Code
CY - Calendar Year
DDW - State Water Resources Control Board, Division of Drinking Water
DMMs - Demand Management Measures
DWR - California Department of Water Resources
EPA - U.S. Environmental Protection Agency
ETo - Reference Evapotranspiration
FY - Fiscal Year
GPCD (or gpcd) - Gallons per Capita per Day
GSP - Groundwater Sustainability Plan
ILI – Infrastructure Leakage Index
LUE - Land Use Element
MGD - Million Gallons per Day
MJHMP - Multi-Jurisdictional Hazard Mitigation Plan
MWELO - Model Water Efficient Landscape Ordinance
NPDES - National Pollutant Discharge Elimination System
PCE - Tetrachloroethylene
RWQCB - Regional Water Quality Control Board
SAY - Safe Annual Yield
SB X7-7 - Senate Bill Seven of the Senate’s Seventh Extraordinary Session of 2009
SDWA - Safe Drinking Water Act
SGMA - Sustainable Groundwater Management Act
SWRCB - State Water Resources Control Board
THMs/TTHMs- Trihalomethanes/Total Trihalomethanes
UWUO - Urban Water Use Objective
UWMP - Urban Water Management Plan
WRRF - City of San Luis Obispo Water Resources Recovery Facility
WSCP - Water Shortage Contingency Plan
WTP - City of San Luis Obispo Water Treatment Plant
WWE - Water and Wastewater Element
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EXECUTIVE SUMMARY AND LAY DESCRIPTION
The City of San Luis Obispo prepared this 2025 Urban Water Management Plan (UWMP) to evaluate
current and future water use, describe the City’s available water supplies, assess water supply reliability,
and document the City’s approach to drought planning a nd water shortage response. Urban Water
Management Plans are required by State law and are updated every five years accordingly. This UWMP
evaluates the City’s water supply reliability through 2050 and supports coordination between water supply
planning, land use planning, infrastructure planning, drought preparedness, and the City’s General Plan.
The City provides potable water service within the city limits and delivers recycled water for approved non -
potable uses, including landscape irrigation, construction-related uses, and other authorized uses. The
City’s water supply portfolio includes multiple surface water reservoirs, recycled water, and planned
groundwater production. This diverse water supply portfolio has been developed over many decades and
helps reduce overreliance on any single water source.
The City’s primary potable water supplies are Salinas Reservoir, Whale Rock Reservoir, and Nacimiento
Reservoir. Salinas and Whale Rock reservoirs are local surface water supplies that are operated together
and evaluated through a combined safe annual yield analysis. Nacimiento Reservoir provides a separate
contractual supply that is delivered through the Nacimiento Water Project. The City is also implementing
projects to restore groundwater production as a supplemental potable water supply. Groundwater is
expected to improve supply diversification and provide additional local water supply reliability once
extraction, treatment, regulatory, and operational requirements are in place.
Recycled water is produced at the City’s Water Resource Recovery Facility and is used for approved non -
potable purposes. Recycled water offsets potable water demand where recycled water service is available,
but it is evaluated separately from potable water because it is not available to meet drinking water demands.
The amount of recycled water that can be beneficially used depends on customer demand, seasonal
irrigation patterns, required discharge to San Luis Obispo Creek, storage capacity, pumping capaci ty, and
recycled water distribution infrastructure. The City expects recycled water use to continue growing over
time as additional customers, system improvements, and beneficial use opportunities become feasible.
This UWMP distinguishes between long-term water supply planning and near-term operational reliability
analysis. For long-term planning, the City uses General Plan and Water and Wastewater Element
assumptions to evaluate whether existing and planned supplies are sufficient to serve projected growth
over the UWMP planning horizon. Long-term demand projections are based on General Plan population
assumptions and the City’s 117 gallons per capita per day planning value. This approach is intentionally
conservative because it evaluates water supply sufficiency many years into the future, when population,
land use, customer water use patterns, climate, regulations, infrastructure conditions, and source
availability may differ from current conditions.
For near-term operational reliability analysis, the City uses more current information, including actual
reservoir storage, recent water use, current population estimates, seasonal demand patterns, source
availability, known infrastructure constraints, rec ycled water availability, groundwater project status, and
dry-year assumptions. These near-term analyses include the City’s annual Water Supply and Demand
Assessments, Water Shortage Contingency Plan implementation, and the five-year drought risk
assessment required as part of this UWMP. This approach is more appropriate for near-term analysis
because the City has better information about actual operating conditions and expected customer demand
over the next one to five years than it does over the full multi-decade UWMP planning horizon.
The City’s current water use remains substantially lower than the long-term 117 gallons per capita per day
planning value used for multi-decade planning. This reflects the community’s long-standing water
conservation ethic, water efficiency improvements, recycled water use, and ongoing demand management
programs. The UWMP continues to use the higher 117 gallons per capita per day value for long -term water
supply planning because it provides a conservative planning buffer for future uncertainty. However, nea r-
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term assessments use more current demand information to avoid overstating expected customer demand
during upcoming assessment periods.
Based on the analysis in this UWMP, the City’s existing and planned water supplies are projected to be
sufficient to meet projected demands through 2050 under normal-year, single dry-year, and multiple dry-
year conditions. The City’s long-term water supply planning values include the City’s contractual supply
from Nacimiento Reservoir, the combined safe annual yield of Salinas and Whale Rock reservoirs, planned
groundwater production when available, recycled water use, and long-term planning adjustments to
account for reservoir siltation.
The City’s five-year drought risk assessment provides a more focused near-term evaluation of water supply
reliability. This analysis evaluates whether projected supplies are sufficient to meet projected demands
during the five-year drought risk assessment period. The City’s Water Projection Model supports this
analysis by evaluating how current and projected demands affect available supplies and by estimating the
number of years of available water supply remaining under the input conditions. This helps the City
determine whether it should remain in normal operations or consider response actions under the Water
Shortage Contingency Plan.
The City’s Water Shortage Contingency Plan provides the framework for responding to water shortage
conditions. Water shortages can result from drought, infrastructure failure, water quality issues, regulatory
requirements, seismic events, wildfire impacts, power outages, or other emergency conditions that affect
the City’s ability to access, convey, treat, or deliver water. The Water Shortage Contingency Plan includes
staged response actions that may be implemented if available supplies decline or if other conditions create
a water shortage.
The City’s major water supply reliability efforts include:
• Restoring full Nacimiento Reservoir conveyance capacity following damage to the Nacimiento
transmission system;
• Restoring groundwater production as a supplemental potable water supply;
• Continuing to optimize and expand recycled water use where feasible;
• Evaluating potable reuse opportunities;
• Participating in regional studies related to desalination feasibility;
• Continuing long-term water conservation and demand management programs; and
• Investing in water treatment, transmission, storage, distribution, recycled water, groundwater, and
emergency response infrastructure.
This UWMP concludes that the City’s diversified water supply portfolio, planned groundwater restoration,
recycled water program, conservation efforts, and ongoing infrastructure investments provide a reliable
basis for meeting projected water demands through 2050. The City’s multi-generational investments in
surface water supplies, recycled water, water treatment, conservation, and system resiliency have
positioned the City to meet expected demands during normal years and through periods of extended
drought. The investments the City has made reduce overreliance on any single source of supply and
provide the operational flexibility needed to respond to changing hydrologic, regulatory, infrastructure, and
demand conditions. The City will continue to monitor water supply conditions, update planni ng assumptions
as new information becomes available, implement demand management measures, pursue planned supply
and infrastructure improvements, and use the Water Shortage Contingency Plan to guide response actions
if shortage conditions occur.
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CHAPTER 1: PLAN INTRODUCTION AND OVERVIEW
1.1 Urban Water Management Planning Act
The City’s Urban Water Management Plan (UWMP) was prepared in accordance with the Urban Water
Management Planning Act (UWMP Act). The UWMP Act is defined by the California Water Code (CWC),
Division 6, Part 2.6, and Sections 10610 through 10656. The UWMP Act requires every urban water
supplier that provides water for municipal purposes to more than 3,000 service connections or supplies
more than 3,000 acre-feet (AF) of water annually, to adopt and submit a plan every five years to the
California Department of Water Resources (DWR).
Since its passage in 1983, the UWMP Act has been amended periodically to address evolving water
management challenges and statewide policy objectives. Significant amendments include the 2009
enactment of Senate Bill X7-7 (SB X7-7), which required each urban retail water supplier to develop urban
water use targets to help meet the statewide 20 percent water use reduction goal by 2020 and an interim
ten percent goal by 2015.
Over time, the UWMP Act has expanded to place greater emphasis on long-term water supply reliability,
water use efficiency, drought preparedness, water loss reduction, integrated water management planning,
and resiliency in response to changing hydrologic and climate conditions. These considerations are
reflected throughout the City’s 2025 UWMP and Water Shortage Contingency Plan (WSCP).
The City’s 2025 UWMP serves as a foundational planning document and source of information for
preparation of Water Supply Assessments (Water Code Section 10910 et seq.) and a Written Verification
of Water Supply (Government Code Section 66473.7), both of which require detailed evaluation of water
supply availability prior to approval of certain development projects.
1.2 Purpose of the 2025 UWMP
The 2025 UWMP serves as both a regulatory compliance document and a long -range water resources
planning tool. Understanding the purpose and intended use of the UWMP provides context for how the
document supports water supply planning, infrastructure investment, drought preparedness, regulatory
compliance, land use coordination, and long-term management of the City’s water system. The UWMP is
intended to provide a technical and policy framework that can be referenced by City staff, decision-makers,
regulatory agencies, and the public as water management conditions evolve over time.
The purpose of the 2025 UWMP is to:
1. Assess past, current, and future water use in the community;
2. Describe the existing and planned potable and non-potable water supplies, water rights,
infrastructure, and water system operations;
3. Evaluate water supply reliability under normal, single dry -year, and multiple dry-year conditions;
4. Assess drought risk and establish a framework for responding to water shortages through the
WSCP;
5. Support long-term water supply planning and coordination with land use planning efforts, including
the City’s General Plan and regional planning initiatives;
6. Document the City’s water demand management measures and ongoing conservation efforts;
7. Demonstrate compliance with applicable provisions of the Urban Water Management Planning Act
and Senate Bill X7-7;
8. Provide a technical and policy reference for the City’s water system, including its background,
operations, infrastructure, regulatory considerations, and future planning;
9. Serve as a source document on the history, management, and reliability of the water supply system;
10. Support planning for future infrastructure improvements, changing hydrologic conditions, regulatory
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requirements, and climate-related uncertainties; and
11. Maintain eligibility for State grants, loans, and other funding opportunities related to water
infrastructure and water management.
The 2025 UWMP evaluates current and projected water demands and available water supplies through the
year 2050, describes the City’s water treatment and distribution systems, assesses water supply reliability
and drought risk, and identifies water demand management measures intended to support long-term water
supply reliability and resiliency. Because the UWMP addresses both long-term supply reliability and near-
term drought risk, the Plan distinguishes between long-term water supply planning and near-term
operational reliability analysis. Long-term water supply planning is guided by the General Plan and Water
and Wastewater Element (WWE) and is used to evaluate whether existing and planned supplies are
sufficient to support projected growth through the UWMP planning horizon. Near -term operational reliability
analysis is used for upcoming single-year assessments, WSCP implementation, and the five-year drought
risk assessment, where current storage, recent demand, infrastructure conditions, and known source
constraints provide a more accurate basis for evaluating potential shortages.
1.3 General Plan and UWMP Interface
The City’s General Plan WWE has served as a primary policy framework guiding the provision of water and
wastewater services since its adoption in 1987. The WWE recognizes the critical role water resources and
utility infrastructure play in supporting the community and the influence that water -related policies have on
growth, development, land use, and community character.
The WWE translates the land use assumptions identified in the General Plan Land Use Element (LUE) into
projected water supply and wastewater service demands and establishes policies intended to ensure
adequate utility services are available to support existing and future development. Population projections,
land use assumptions, and anticipated development patterns identified in the General Plan and other
regional and California State adopted data and documents serve as important planning inputs for the
UWMP.
The UWMP supports and informs the WWE by providing detailed analysis of water supply availability,
projected water demands, system operations, drought risk, and long-term water supply reliability. Together,
these documents help ensure that water supply planning, infrastructure planning, and l and use planning
remain closely coordinated.
The Water Management section of the WWE was originally developed during a period of water supply
constraint in the late 1980s, when planning efforts focused heavily on the allocation and management of
limited water supplies. The WWE has subsequently been revised periodically, most recently in 20 25, to
reflect updated planning assumptions, regulatory requirements, and long-term water resource management
considerations. These updates continue to emphasize balancing available water supplies with existing
demands and future growth anticipated under the General Plan.
The General Plan and WWE provide the policy basis for the City’s long-term water demand and supply
planning. For long-term planning, projected demands are based on General Plan population assumptions
and the City’s 117 gpcd planning value, while supply availability is based on es tablished long-term planning
values for the City’s water supply portfolio. The UWMP also includes near -term operational reliability
analysis for the five-year drought risk assessment. That near-term analysis is not intended to replace the
General Plan and WWE accounting framework; rather, it evaluates whether current and near-term supplies
are sufficient to meet expected demands during the upcoming one- to five-year period.
1.4 Organization of the UWMP
The City’s 2025 UWMP is organized into chapters addressing the major planning components required
under the UWMP Act. The UWMP includes evaluation of water demands, available water supplies, water
supply reliability, drought risk, water shortage response actions, and water demand management
measures, as required by the California Water Code. The organization of the UWMP is summarized below.
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Executive Summary
Provides a high-level overview of the City’s water system, water supplies, projected water supply
and demand, water supply reliability, drought preparedness, and major findings of the 2025 UWMP.
Chapter 1: Plan Introduction and Overview
Provides background on the Urban Water Management Planning Act, the purpose of the UWMP,
and the relationship between the UWMP and other planning documents.
Chapter 2: Plan Preparation
Describes the basis for preparing the UWMP, coordination and outreach efforts, and plan
preparation requirements.
Chapter 3: Service Area Description
Provides an overview of the City’s service area, population, climate, land use characteristics, and
water service area.
Chapter 4: Water Use Characterization
Describes historical, current, and projected potable and non-potable water demands within the
City’s service area.
Chapter 5: SB X7-7 Baselines, 2020 Targets, and 2025 Reporting
Documents compliance with Senate Bill X7-7 urban water use reduction requirements and
associated reporting metrics.
Chapter 6: Normal-Year Water Supply Characterization
Describes the City’s water supply sources, water rights, infrastructure, water system operations,
and projected future water supplies.
Chapter 7: Water Service Reliability and Drought Risk Assessment
Evaluates water supply reliability under normal, single dry -year, and multiple dry-year conditions
and includes the City’s Drought Risk Assessment.
Chapter 8: Water Shortage Contingency Planning & Emergency Supply Resiliency
Describes the City’s response framework for water shortage conditions, supply interruptions, and
drought emergencies.
Chapter 9: Demand Management Measures
Summarizes the City’s water conservation and demand management programs and ongoing efforts
to improve water use efficiency.
Chapter 10: Adoption, Submittal, and Implementation
Documents the public review, adoption, submittal, and implementation process for the UWMP.
Appendices
Provide supporting technical information, reference materials, submittal tables, and supplemental
documentation associated with the UWMP.
The City’s 2025 Water Shortage Contingency Plan (WSCP) is published as a separate document and is
incorporated by reference into this UWMP in accordance with Water Code requirements. The WSCP may
be amended separately from the UWMP if necessary to address changing conditions, regulatory
requirements, or operational needs.
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1.5 Relationship to Other Planning Documents
The City’s 2025 UWMP was developed in coordination with other local and regional planning efforts related
to water resources, infrastructure planning, emergency preparedness, sustainability, and long -term
community development. These planning documents provide supporting technical information, policy
direction, operational guidance, and planning assumptions that help inform the UWMP and promote
consistency between related planning efforts.
The UWMP both supports and relies upon information contained in other planning documents prepared by
the City and regional agencies. These documents collectively assist the City in evaluating water supply
reliability, infrastructure needs, drought preparedness, emergency response capabilities, regulatory
compliance obligations, and long-term water resource management strategies.
Examples of planning documents include, but are not limited to:
• City of San Luis Obispo General Plan and Water and Wastewater Element
• 2025 Water Shortage Contingency Plan
• Long-term water infrastructure replacement plans
• San Luis Obispo Valley Basin Groundwater Sustainability Plan
• County of San Luis Obispo Integrated Regional Water Management Plan
• Recycled water and wastewater management plans
• Emergency response plans and hazard mitigation plans
Information developed through these planning efforts was incorporated into the UWMP where appropriate
to support consistency between water supply planning, land use planning, infrastructure planning, and long -
term resource management objectives. The UWMP also serves as a reference document for future planning
studies, infrastructure projects, environmental review processes, and water resource management
decisions undertaken by the City and other agencies. Because many water resource management issues
extend beyond jurisdictional boundaries, coordination between local and regional planning efforts remains
an important component of long-term water supply reliability planning.
CHAPTER 2: PLAN PREPARATION
2.1 Agency Coordination
The UWMP Act requires the City to coordinate preparation of the UWMP with appropriate agencies,
including cities and counties within which the City provides water, water suppliers that share a common
source, water management agencies, and other relevant public agencies. This chapter describes the City’s
coordination efforts during preparation of the 2025 UWMP. Formal notice, public hearing, adoption, and
post-adoption submittal requirements are documented separately in Chapter 10.
The City’s water supply portfolio includes several regional or jointly managed water resources, including
Whale Rock Reservoir and Nacimiento Reservoir. Although these resources involve multiple agencies, the
City’s projected water supply availability in this UWMP is based on defined water rights, ownership shares,
contractual entitlements, and adopted planning assumptions. The City’s use of these supplies is therefore
evaluated based on the City’s established rights and allocations, rather than on unalloca ted supplies that
would otherwise be available to other agencies. Coordination with partner agencies remains important for
reservoir operations, conveyance reliability, long-term planning, and emergency response; however, the
City’s projected demands and supplies in this UWMP are not assumed to reduce the established
entitlements or allocations of other participating agencies.
Whale Rock Reservoir Commission
Whale Rock Reservoir provides water to the City, California Polytechnic State University (Cal Poly), the
California Men’s Colony, and the town of Cayucos. The Whale Rock Commission oversees the reservoir
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operations and is made up of representatives from the City, California Men’s Colony, and Cal Poly, as well
as a representative from the State Department of Water Resources. The City provides staff oversight of
daily operations and maintenance activities of Whale Rock Reservoir. These staff members work closely
with staff from the Commission member agencies to address water planning issues. The City most recently
met with representatives from Cal Poly, a Whale Rock Commission Member, to discuss community water
use and population growth forecasts for both entities on March 17, 2026.
Cayucos Area Water Organization
The Cayucos Area Water Organization (CAWO) includes the three water purveyors that serve the town of
Cayucos (Paso Robles Beach Water Association, Morro Rock Mutual Water Company, County Service
Area 10A) and the Cayucos-Morro Bay Cemetery District. The Whale Rock Commission and CAWO have
an agreement which includes a provision to provide up to 600-acre feet of water per year from the reservoir.
The agreement dates to the period when the dam was being planned and constructed. The agreement has
been amended since that time. The water provided to the CAWO is delivered from the Whale Rock pipeline
to the Cayucos Water Treatment Plant operated by the County of San Luis Obispo (County). City of San
Luis Obispo staff attend CAWO meetings on a regular basis and communicate with agencies regarding
Whale Rock storage volumes, availability, and any periods when water from the reservoir may not be
accessible.
Nacimiento Project Commission
The County has an entitlement of 17,500-acre feet of water from Nacimiento Reservoir and acts as the
wholesaler of this water supply. The County oversees the project that delivers water from Nacimiento
Reservoir to agencies participating in the Nacimiento Water Project. The current participating entities
include the cities of Paso Robles and San Luis Obispo, Atascadero Mutual Water Company, Templeton
Community Services District, Santa Margarita Ranch, Bella Vista Mobile home park, and County Service
Area 10A (Cayucos).
The Nacimiento Project Commission is made up of representatives from each of the four original
participating agencies’ governing boards, as well as a representative from the County Flood Control and
Water Conservation District (i.e. County Board of Supervisors). The Nacimiento Project Commission
provides oversight and recommendations to the District regarding project operations and maintenance and
the associated budget. The County, as the water supply “wholesaler”, was notified during ongoing
discussions that the City was updating its UWMP in March 2026 and again on May 9, 2026.
Integrated Regional Water Management Group
The County has developed an Integrated Regional Water Management Plan which included involvement
and participation by the City as well as other agencies and interested individuals throughout the County ,
collectively referred to as the Integrated Regional Water Management Group . The County was notified
during ongoing discussions that the City was updating its UWMP in March of 2026 and again on May 9,
2026.
2.2 Public Participation and Plan Adoption
The City encouraged public participation during preparation of the 2025 UWMP through public noticing,
availability of the draft plan for review, and a City Council public hearing. The public review, hearing,
adoption, and post-adoption submittal process is described in Chapter 10.
2.3 Plan Implementation
The City prepared the 2025 UWMP on a fiscal-year reporting basis. For purposes of this UWMP, the 2025
reporting year generally corresponds to Fiscal Year 2024 –25 (July 1, 2024 – June 30, 2025) with all fiscal
year periods running from July 1 through June 30. Implementation of the UWMP is the responsibility of the
City’s Public Works and Utilities Department, Utilities Branch. A detailed discussion of plan implementation
requirements is provided in Chapter 10.
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2.4 Standardized Tables
Per the requirements of the CWC, standardized tables for the reporting and submittal of the UWMP data
were developed and are required to be published in this report. The standardization of data tables allows
for efficient data management, expedited review of UWMPs, and compilation of data for regional and
statewide planning. The City will submit UWMP and WSCP data electronically to DWR using standardized
tables and have included the standardized tables within Appendix A.
2.5 Compliance Checklist
The City completed the checklist of specific 2025 UWMP requirements and included it in the Plan as
Appendix B, consistent with DWR guidance. The Checklist includes each 2025 UWMP requirement by
subject, applicable CWC section, and the page number where the required element is addressed in the
Plan. This checklist serves to assist in the DWR review of the City’s 2025 UWMP.
CHAPTER 3: SERVICE AREA DESCRIPTION
3.1 Introduction
This chapter provides an overview of the City of San Luis Obispo’s water service area, demographic
characteristics, land use conditions, and other planning assumptions used in development of the 2025
UWMP. Information contained in this chapter establishes the basis for the City’s current and projected water
demand analysis, water supply reliability evaluation, and long-term water resources planning efforts
described in subsequent chapters of the UWMP.
The City of San Luis Obispo is located in central San Luis Obispo County along California’s Central Coast
and serves as a regional center for residential, commercial, educational, governmental, and recreational
activities. The City provides potable water service within the city limits through a municipally owned and
operated water system consisting of water supply, treatment, storage, transmission, and distribution
infrastructure. The City also delivers recycled water for non-potable use in designated service areas.
The City’s water system is supported by a diversified water supply portfolio consisting primarily of surface
water and recycled water resources, with a project currently under construction to bring groundwater
supplies online as an additional drinking water source. Long-term water supply planning for the City is
influenced by a variety of factors, including population growth, land use planning, water use efficiency
requirements, hydrologic variability, regulatory conditions, infrastructure needs, and cl imate-related
uncertainties. Accordingly, this chapter describes the physical, demographic, and planning characteristics
of the community that support the water demand
and water supply analyses contained in this
UWMP.
The UWMP Act requires urban water suppliers to
evaluate current and projected water demands
over a minimum twenty-year planning horizon.
Consistent with these requirements, the City’s
2025 UWMP evaluates water demand and
supply reliability conditions through the year 2045
and includes additional planning projections
through 2050, as recommended by DWR, using
the best available demographic, land use, and
planning information available at the time the
UWMP was prepared.
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3.2 Service Area Overview
The City of San Luis Obispo is located approximately halfway between Los Angeles and San Francisco
along California’s Central Coast. The City encompasses approximately 13.2 square miles, of which
approximately 13.0 square miles is land and approximately 0.18 square miles is water.
The City serves as the primary urban center within San Luis Obispo County and includes a mix of
residential, commercial, institutional, governmental, educational, and recreational land uses. Major
institutional and community features within or directly adjacent to the City include Cal Poly, Cuesta College,
the downtown commercial core, regional medical facilities, and various public and recreational facilities
serving both residents and visitors.
The City is the sole provider of potable water service within the city limits and maintains water supply,
treatment, transmission, storage, and distribution infrastructure necessary to support existing and future
water demands. In addition to potable water service, the City operates a re cycled water system serving
designated non-potable reuse areas.
3.3 Climate and Hydrologic Conditions
The City is situated within a coastal valley
approximately ten miles inland from the Pacific
Ocean and experiences a Mediterranean climate
characterized by mild, dry summers and cool,
moderately wet winters. Average annual precipitation
within the City is approximately 23 inches, with the
majority of rainfall occurring between November and
April. Summer conditions are generally warm and
sunny, often influenced by marine fog and coastal
weather patterns. Winter temperatures are typically
mild, although periodic freezing temperatures may
occur during colder weather events.
The City’s climate and seasonal weather patterns
influence both water demands and available water
supplies. Irrigation demands generally increase
during the dry summer months when
evapotranspiration rates are highest and precipitation
is limited. However, compared to many inland
California communities, the City experiences less
extreme seasonal water demand variation due to its
moderate coastal climate, long-standing community
emphasis on water conservation and water-efficient
landscaping, and the influence of Cal Poly on water
use, where student populations have historically
declined during summer months when many students
leave the area while irrigation demands are typically
at their highest. Table 3-1 summarizes monthly
evapotranspiration, precipitation, and average
temperature data for the City.
Although the City itself experiences relatively
moderate coastal climate conditions, the watersheds supplying the City’s surface water reservoirs are
located in areas with differing climatic and hydrologic characteristics. The City’s water supply portfolio
includes reservoirs located both closer to the coast and farther inland, where temperatures, precipitation
patterns, evapotranspiration rates, and hydrologic conditions may vary significantly from those experienced
within the City. As a result, hydrologic conditions affecting reservoir storage, watershed runoff, and water
TABLE 3-1: SAN LUIS OBISPO CLIMATE
ETo
(in)
Average
rainfall
(in)
Average
temperature
(F)
January 2.77 5.53 52.3
February 2.72 3.63 55.6
March 3.58 4.99 53.7
April 4.41 0.84 55.6
May 5.86 0.19 58.7
June 5.94 0.07 59.7
July 6.01 0.02 61.1
August 6.14 0.00 64.6
September 4.19 0.31 65.8
October 4.10 0.41 61.6
November 2.44 1.25 58.7
December 2.64 5.49 59.2
Annual 50.80 22.73 58.9
Source:
1. Evapotranspiration (ETo) from: California Irrigation
Management Information System (CIMIS) Station 52,
January 2025 - December 2025.
2. Average rainfall data for 2020-21 through 2024-25:
https://www.slocounty.ca.gov/departments/public-
works/forms-documents/water-resources/monthly-
precipitation-reports/slo-reservoir-precipitation-data-
site-749
3. Average Temperature from: California Irrigation
Management Information System (CIMIS) Station 52,
January 2025 - December 2025.
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supply availability may not directly correlate with weather conditions observed within the City itself.
Because the City relies primarily on surface water supplies obtained from multiple watersheds, hydrologic
conditions and climate data associated with those watersheds are incorporated into the City’s water supply
planning and water management models. Variability in rainfall, runoff, reservoir inflows, and watershed
conditions can differ significantly between watersheds and may substantially influence long -term water
supply availability and reliability.
3.4 Water System Overview
The City operates a municipally owned and operated potable water system that includes water supply,
treatment, transmission, storage, pumping, and distribution infrastructure necessary to provide reliable
water service to the community. The City’s water system has been developed over many decades and
includes multiple water supply sources, regional conveyance facilities, water treatment infrastructure, and
an interconnected distribution system designed to support both domestic water use and fire protection
demands.
3.4.1 Water Supply Sources
The City utilizes three surface water
reservoirs to meet potable water
demands. Salinas Reservoir, located
southeast of the community of Santa
Margarita, has provided water to the City
since 1944. Whale Rock Reservoir,
located near the community of Cayucos,
has served as a City water source since
1961. Deliveries from Nacimiento
Reservoir to the City began in 2011
following completion of the Nacimiento
Water Project. Collectively, these
supplies provide the foundation of the
City’s long-term potable water supply
portfolio.
Raw water from each reservoir is
conveyed to the City’s Water Treatment
Plant (WTP) through three separate
transmission systems. The City’s
diversified surface water portfolio
provides operational flexibility and helps
reduce dependence on any single water
source or watershed.
The City does not currently rely on local
groundwater to meet normal potable
water demands; however, groundwater
was used extensively during previous
drought conditions and is planned to return to service beginning in FY 2027-28 through development of
new groundwater production wells and treatment facilities. In addition to potable supplies, the City also
produces recycled water at the Water Resource Recovery Facility (WRRF) for landscape irrigation,
construction-related activities, and other approved non-potable uses. In 2025, the City completed upgrades
to the WRRF intended to improve recycled water quality, maximize recycled water production, and allow
for the increased utilization of recycled water resources in the future.
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3.4.2 Water Treatment Facilities
The City’s Water Treatment Plant (WTP) is located on Stenner Creek Road, northwest of the Cal Poly
campus. The facility was constructed in 1964 to provide treatment of surface water from Salinas and Whale
Rock Reservoirs. The WTP is a conventional plant that includes ozone disinfection, coagulation,
flocculation, sedimentation, and filtration. The WTP was originally designed to treat up to eight million
gallons per day (mgd). In 1977, the plant was upgraded to provide 11.5 mgd of treatment capacity but
actually treated up to 12 mgd for limited periods during peak summertime water demands.
Since the WTP was constructed, drinking water treatment regulations have become increasingly protective
of public health. The Safe Drinking Water Act (SDWA), adopted in 1974 and significantly amended in 1986,
established the national framework for regulating public drinking water systems. Following the 1986
amendments, the U.S. Environmental Protection Agency (EPA) adopted several major rules affecting
surface water treatment, including the Surface Water Treatment Rule, which established treatment
requirements for surface water supplies to reduce the risk of waterborne disease. In 1994, the City
completed a major WTP upgrade to comply with new regulatory requirements and to convert the WTP’s
primary disinfectant to ozone. Ozone provides a high level of disinfection for surface water supplies,
reduces the need to rely on chlorine for primary disinfection, and helps reduce the formation of
trihalomethanes (THMs), also referred to as total trihalomethanes (TTHMs) when measur ed as a regulated
group. The use of ozone also helps address taste and odor issues associated with source water conditions
such as algae blooms at Salinas Reservoir. Even after the installation of ozone is the WTP’s primary
disinfectant, chlorine continues to be added after filtration to maintain a disinfectant residual in the water
distribution system.
An upgrade completed in 2008 added additional onsite storage facilities, replaced an existing on -site pump
station, and replaced the WTP’s sedimentation basin with a new ballasted flocculation process, known as
Actiflo. The addition of the Actiflo process increased sedimentation capacity from eight mgd to 16 mgd,
improving the WTP’s ability to reliably meet expected future water demand.
Although the City’s treatment process helps reduce the formation of TTHMs, disinfection byproducts can
continue to form after treated water enters the distribution system. TTHM levels are influenced by factors
such as water temperature, natural organic mat ter, chlorine residual, and water age. Higher TTHM levels
can occur where water age is greater, often resulting from oversized storage tanks with lower turnover or
limited mixing. During recent drought periods, reduced water use and increased conservation contributed
to lower turnover in some storage facilities, which increased the need for additional distribution system
water quality improvements.
To address these conditions, the City has completed several projects to improve treated water storage and
distribution system water quality. In 2020, mixing, aeration, and ventilation equipment was installed at
Clearwell 2 at the WTP and at Edna Saddle Tank in the distribution system. Additional projects completed
in 2021 and 2024 added tank mixing, chlorine analyzers, and automated chlorine dosing at Reservoir 1 and
Reservoir 2, the City’s two largest treated water storage tanks. These improvements support more
consistent disinfectant residual management, reduce water age impacts, and help the City maintain
compliance with drinking water regulations while continuing to provide high-quality water to customers.
Also in 2020, the City entered into a public/private partnership with Pacific Gas and Electric (PG&E) for the
Water Energy Efficiency Project at the WTP. Project components included upgrading the ozone generation
system, SCADA system, plant service water system, and improvements to the Transfer Pump Station. It is
estimated that implementation of the Water Energy Efficiency Project will result in a reduction of energy
usage of roughly 33 percent when compared to 2019 WTP operations.
Following the initiation of the partnership with PG&E, the City received grants to support the installation of
a diesel-powered backup generator that allows the WTP to operate during power outages. This generator
was supplemented by the installation of a Tesla backup battery that allows the WTP to reduce electrical
demand during peak energy pricing periods and power the plant for up to ten hours during a short-duration
power outage. These two assets allow the City to continue treating and delivering water d uring power
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outages, which have increased in frequency and duration following significant wildfires across the State.
3.4.3 Potable Water Distribution System
The City’s potable water distribution system conveys treated water from the WTP to approximately 17,500
service connections and more than 2,000 public fire hydrants. The system includes approximately 190 miles
of water mains, eight treated water storage facilities, and seven pump stations.
The distribution system is divided into two primary networks: a high -pressure system and a low-pressure
system. These systems largely operate independently from one another due to the City’s varied topography.
Water serving the higher elevation portions of the City is pumped from the WTP through the Transfer Pump
Station into the high-pressure zones. The high-pressure system serves the Cal Poly campus and portions
of the City generally located north and east of the Union Pacific Railroad tracks. Water servi ng lower
elevation areas flows by gravity from the WTP Clearwell storage facilities into the lower -pressure service
zones.
To accommodate the City’s topography and service area elevations, the distribution system is further
divided into 11 pressure zones. These zones are designed to maintain system pressures generally between
40 and 80 pounds per square inch (psi) under normal operating conditions. Maintaining appropriate
pressure is important for protecting distribution system water quality, supporting domestic water use,
meeting fire protection needs, and reducing water loss that can occur when pressures are excessive.
Treated water storage is a key component of the City’s distribution system. Storage facilities provide
operational flexibility, stabilize pressure, support emergency response, and provide fire flow capacity. The
City’s treated water storage system includes five steel tanks and three concrete storage facilities with a
combined storage capacity of more than 25 million gallons.
The City’s potable water system also includes transmission and distribution mains constructed from a
variety of pipe materials, including cast iron, ductile iron, asbestos cement, polyvinyl chloride (PVC), copper,
polyethylene, and other materials installed during different periods of system development. Portions of the
distribution system are approaching or have exceeded their anticipated service life. As a result, ongoing
maintenance, rehabilitation, and replacement are necessary to maintain system reliability, minimize service
disruptions, and reduce water loss. Pipeline replacements are prioritized through implementation of the
City’s Potable Water Distribution System Operations Master Plan.
The distribution system also supports fire protection through a network of more than 2,000 public hydrants
and approximately 200 private hydrants located throughout the community. Hydrant maintenance, testing,
and replacement activities are performed regularly by Utilities Branch staff to maintain fire flow reliability
and operational readiness.
The City implements preventative maintenance programs throughout the distribution system to support
long-term reliability and operational performance. These programs include water main maintenance and
repair, pump station maintenance, storage facility inspe ction and maintenance, valve exercising, pressure
reducing valve maintenance, hydrant testing and maintenance, cross -connection control program
management, and distribution system water quality monitoring and sampling.
The City currently uses a contract service provider for meter reading operations to support standardized
billing periods. In recent years, the City has begun implementing an Advanced Metering Infrastructure (AMI)
system to improve water use monitoring, support conservation efforts, enhance water loss management,
and provide customers with better access to water use information. As of 2025, approximately 5,000 meters
had been equipped with radio communication endpoints as part of a phased transition to a full AMI system
anticipated to be completed in 2028. Once complete, the AMI system is expected to provide more timely
and detailed water use data, improve leak detection capabilities, reduce inefficiencies associated with
manual meter reading, and support long-term water management and conservation planning. AMI will also
improve the City’s ability to monitor customer water use and support implementation of the Water Shortage
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Contingency Plan during water shortage emergencies.
3.4.4 Recycled Water System
The City of San Luis Obispo operates a recycled water system utilizing disinfected tertiary -treated effluent
produced at the City’s WRRF. The recycled water system was developed as part of the City’s long -term
strategy to maximize beneficial reuse of available water resources, reduce potable water demands where
feasible, and improve overall water supply resiliency. The City’s recycled water program operates in
accordance with applicable State regulations governing recycled water use, including Title 22 of t he
California Code of Regulations and requirements established by the Regional Water Quality Control Board
(RWQCB).
The City’s WRRF is located on Prado Road in the southern portion of the City and serves residential,
commercial, industrial, institutional, and governmental wastewater customers within the community,
including Cal Poly and the County Regional Airport. The WRRF provides tertiary treatment prior to
discharge or reuse and has undergone multiple upgrades intended to improve treatment reliability,
regulatory compliance, and recycled water production capabilities.
The City’s Water Reuse Project, completed in 2006, included improvements to the WRRF and construction
of approximately eight miles of recycled water distribution pipeline. The recycled water system includes a
dedicated recycled water pump station and stora ge tank located at the WRRF. The distribution system
primarily serves landscape irrigation demands at parks, schools, roadway medians, common areas,
Caltrans facilities, Laguna Lake Golf Course, and other approved non -potable reuse sites throughout the
southern portions of the City. The City also operates a construction water permit program that allows
recycled water to be utilized for dust control and compaction activities at approved construction sites.
The City’s recycled water system was designed to allow for future expansion as additional recycled water
demands are identified. In addition to existing recycled water use, the City has evaluated opportunities for
future recycled water system expansion and potential future potable reuse applications through
development of the City’s Recycled Water Master Plan and related planning studies.
The City’s recycled water supply varies seasonally based on wastewater generation, irrigation demand,
storm-related inflow and infiltration, treatment plant operations, and other operational considerations. The
City is also required to discharge approximately 1.6 million gallons per day of treated wastewater effluent
to San Luis Obispo Creek to maintain minimum flows for downstream aquatic habitat. Because this
environmental discharge requirement represents a fixed daily commitment, the volume of recycled w ater
available for customer use depends on the amount of treated effluent remaining after this requirement is
met.
3.5 Existing Population and Demographic Characteristics
The City of San Luis Obispo was founded in 1772 and incorporated in 1856, making it one of California’s
oldest communities. Today, the City serves as the civic, economic, educational, and cultural center of San
Luis Obispo County. The City supports a diverse mix of residential, commercial, governmental, educational,
healthcare, and recreational land uses that contribute to both resident and regional water demands.
The City’s estimated 2025 population was 49,849, according to California Department of Finance
estimates 1 . Based on these estimates, between 2021 and 2025, the City’s population increased by
approximately 2,449 people, which is generally consistent with the one percent growth assumptions
established in the City’s General Plan. Future growth within the City is anticipated to occur within the
Margarita, Orcutt, Airport Area, and Froom Ranch Specific Plan areas, as well as through infill development
and intensification of existing developed areas including portions of the downtown core and other mixed -
1 Population estimates for the City of San Luis Obispo are available at the California Department of Finance website
at: https://dof.ca.gov/media/docs/forecasting/Demographics/estimates/e-4-population-estimates-for-cities-counties-
and-the-state-2021-2026-with-2020-census-benchmark/E-4_2026_InternetVersion.xlsx
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use areas.
The City’s age demographics are relatively well
distributed. According to Regional Economic Action
Coalition demographic information for 2025 (Applied
Geographic Solutions, June 2025), approximately 22
percent of the population is under the age of 20, 21
percent is between the ages of 20 and 24, 23 percent is
between the ages of 25 and 44, 17 percent is between the
ages of 45 and 64, and 17 percent is 65 years of age or
older2.
The City is the cultural hub of the Central Coast with a
daytime population of up to 90,000 people, nearly double
its permanent population. With major regional employers
located within or adjacent to City limits, the City is not only
the cultural hub but also the civic and economic hub in the
region. Public sector jobs account for a sizeable portion of the job market in the City. Service and retail jobs
also comprise a large percentage of employers. The City’s median household income was $73,685 (in 2024
dollars3), up from $56,071 in 2019. The City's 2025 Annual Comprehensive Financial Report documents
the top employers within and adjacent to the City, as shown in Table 3-2.
TABLE 3-2: TOP EMPLOYERS
# Employer # of Employees
1 California Polytechnic State University (Cal Poly) 3,177
2 County of San Luis Obispo 2,956
3 Cal Poly Corporation (Foundation) 2,787
4 Pacific Gas & Electric Company (PG&E) 1,824
5 California Men’s Colony 1,350
6 San Luis Coastal Unified School District 1,070
7 Sierra Vista Regional Medical Center 779
8 Cuesta Community College 773
9 French Hospital Medical Center 688
10 City of San Luis Obispo 654
Source: City of San Luis Obispo 2025 Annual Comprehensive Financial Report (Schedule 21 –
Principal Employers)
3.6 Future Population Projections
The City’s General Plan Land Use Element (LUE), Housing Element, and WWE provide important planning
assumptions related to future population growth, land use, housing, and water demand. For purposes of
the 2025 UWMP, the City uses the population growth methodology outlined in the General Plan LUE as the
basis for long-term water demand forecasting.
The General Plan LUE establishes a residential growth management framework under which the City
manages growth of the housing supply so that it does not exceed one percent per year on average, subject
to specific exclusions and implementation provisions. The LUE includes projected population assumptions
2 https://reachcentralcoast.org/demographics/
3 https://www.census.gov/quickfacts/fact/dashboard/sanluisobispocitycalifornia/PST045219
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through 2035 and identifies an estimated urban reserve capacity of approximately 57,200 persons. For
UWMP demand-planning purposes, the City uses the General Plan population growth framework through
2035 and extends the one-percent annual growth methodology through 2050 to evaluate long-term water
supply and demand reliability.
Use of the General Plan growth methodology provides a conservative basis for water supply planning
because actual population growth has generally occurred at a slower rate than the maximum growth
assumptions identified in the General Plan LUE.4 This approach is intended to ensure that the UWMP
evaluates water supply reliability under a planning scenario that is consistent with adopted City land use
policy and sufficiently conservative for long-term water supply planning.
Table 3-3 summarizes the City’s estimated current 2025 population, the LUE population planning
assumptions through 2035, and the UWMP’s demand-planning population projections through 2050 based
on extending the General Plan’s one-percent annual growth methodology beyond 2035.
TABLE 3-3: CITY POPULATION PROJECTIONS
2025 2030 2035 2040 2045 2050
Census-based City Population
(2025)1 49,849 - - - - -
General Plan LUE Projected
Population2 51,317 53,934 57,200 - - -
Projected Population Assuming
One Percent Annual Growth
Beyond 2035 LUE Projections3
- - - 60,118 63,184 66,407
Notes:
1. 2025 population estimate for the City of San Luis Obispo is from the California Department
of Finance website at: https://dof.ca.gov/forecasting/demographics/estimates-e1/
2. 2025, 2030 and 2035 population planning assumptions are based on City of San Luis
Obispo, General Plan, LUE, Table 3.
3. 2040, 2045, and 2050 population planning assumptions extend the General Plan’s one -
percent annual growth methodology beyond 2035 for UWMP water demand-planning
purposes.
Population projections and future water demand assumptions utilized within this UWMP are intended solely
for purposes of evaluating long-term water supply reliability, infrastructure planning, drought preparedness,
and compliance with the Urban Water Management Planning Act. Nothing within this UWMP establishes
land use entitlements, approves future development projects, or modifies the City’s adopted General Plan
land use designations, growth management policies, or development review procedures.
3.7 Land Use Characteristics and Planning Assumptions
The City’s land use planning framework is established through the City’s General Plan LUE and WWE,
which together guide future growth, infrastructure planning, resource management, and long -term service
planning within the community. The General Plan establishes a planning framework intended to preserve
the City’s compact urban form, maintain separation between urban development and surrounding open
space and agricultural lands, and support sustainable growth patterns consistent with community values
and available infrastructure capacity.
The General Plan emphasizes a development pattern focused on infill development, redevelopment, mixed-
use activity centers, and planned expansion within identified Specific Plan, special focus, and expansion
areas rather than broad outward expansion of the City’s urban footprint. Future residential, commercial,
4 2025 State Department of Finance estimated population of 49,849 versus Land Use Element 2025 estimate of 51,317.
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mixed-use, and institutional growth is anticipated to occur primarily within the Margarita Area, Orcutt Area,
Airport Area, Avila Ranch, Froom Ranch, and other identified Specific Plan and Special Focus Areas, as
well as through intensification of existing developed areas, including portions of the downtown core and
established commercial corridors.
The City’s planning framework places significant emphasis on preservation of open space, agricultural
resources, hillsides, creek corridors, habitat areas, and other environmental resources surrounding the City.
The General Plan identifies the importance of maintaining a clear boundary between urban development
and surrounding open space while encouraging a compact urban form and efficient use of existing
infrastructure and public services.
Land use planning assumptions utilized in the
2025 UWMP are intended to remain generally
consistent with the City’s General Plan and
related planning documents. For purposes of this
UWMP, these assumptions provide a planning
basis for evaluating future water demands,
infrastructure needs, and long-term water supply
reliability. Actual development timing, location,
and intensity may vary over time based on market
conditions, project approvals, infrastructure
sequencing, housing production, regional growth
trends, and other factors.
The City’s land use and infrastructure planning
efforts are also influenced by sustainability and
climate-related planning objectives contained within the General Plan. These objectives include
encouraging sustainable infrastructure, reducing greenhouse gas emissions, supporting alternative
transportation modes, improving energy efficiency, protecting natural resources, reducing the jobs/housing
ratio, and fostering resilient long-term community development patterns.
The City implements and enforces water-efficient development requirements consistent with applicable
State regulations and local policies, including the State Model Water Efficient Landscape Ordinance
(MWELO), California Green Building Standards Code (CALGreen), low impact development requirements,
non-functional turf prohibitions and reductions, and other water conservation -related development
standards. These requirements are intended to improve long-term water use efficiency, reduce irrigation
demands, encourage sustainable landscape practices, and support the City’s long -term water supply
reliability objectives. Modern water efficiency standards also allow the City to develop more refined long -
term water demand projections by better reflecting the reduced indoor and outdoor water use characteristics
of contemporary development compared to historical development that occurred before current water
efficiency requirements.
CHAPTER 4: WATER USE CHARACTERIZATION
4.1 Introduction
This chapter describes the City’s historical potable water demands, current water use characteristics, and
projected future water demands through the UWMP planning horizon (2025-2050). The City’s potable water
demands are influenced by a variety of factors including population growth, land use patterns, climate
conditions, conservation practices, economic activity, seasonal irrigation demands, and water-efficient
development standards.
Water demand projections developed in this chapter are used to evaluate future water supply reliability,
drought preparedness, infrastructure planning, and compliance with the UWMP Act.
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This chapter also summarizes the City’s water loss auditing program, gross water use calculations, and per
capita water use metrics utilized for compliance with SWRCB requirements.
4.2 Demand Sector Definitions
Potable water demand in the City is comprised of several sectors5, consisting of the following:
• Single-family Residential: A single-family dwelling unit. A lot with a free-standing building
containing one dwelling unit that may include an attached or detached accessory dwelling
unit (ADU) or Junior ADU.
• Multi-family Residential: Multiple dwelling units contained within one building or several
buildings within one complex.
• Landscape: Water connections supplying water solely for landscape irrigation. Such
landscapes may be associated with multi-family, commercial, industrial, or
institutional/government sites, but are considered a separate water use sector if the
connection is solely for landscape irrigation.
• Commercial: A water user that provides or distributes a product or service.
• Industrial: A water user that is primarily a manufacturer or processor of materials as
defined by the North American Industry Classifications System (NAICS) code sectors 31
to 33, inclusive, or an entity that is a water user primarily engaged in research and
development.
• Institutional: A water user dedicated to public service. This type of user includes, among
other users, higher education institutions, schools, courts, churches, hospitals, government
facilities, and nonprofit research institutions.
• Distribution System Losses: Examples of system losses are provided in
• Table 4-4: Common Water Loss & Unbilled Consumption Types4.
4.3 Historical Water Demand
Historically, the City experienced high per capita potable water demands leading into the drought of the late
1980s and early 1990s. During this severe drought, the City implemented strict water conservation
measures intended to reduce potable water demand to preserve limited available water supplies. These
measures included mandatory conservation requirements, restrictions on outdoor irrigation, a set allotment
of water based on business type (for commercial properties) and number of residents (for residential
5 The City compiles commercial, industrial, and institutional accounts in one category known as “CII” consistent with
CWC 10608.12.
Examples of Water Loss & Unbilled Authorized Consumption Causes
Water Loss Mainline & Service Line
Leakage Meter Inaccuracies Data Handling
Errors
Overflow of
Storage Tanks
Unbilled
Authorized
Consumption
Treatment Plant and
Distribution System
Process Water
Mainline Flushing Fire Flow Testing Water Quality
Testing
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properties), and other demand reduction strategies. Although these efforts resulted in substantial reductions
in potable water use, much of the reduction observed during that period was associated with temporary
behavioral changes in response to drought conditions and City regulations, rather than long-term
permanent reductions in baseline water demand.
As drought conditions improved during the 1990s, potable water demand gradually increased again through
the late 1990s, where water demand ultimately plateaued from around 1997 through 2009. Around 2009-
2010 the City implemented significant water rate increases associated with construction and operation of
the Nacimiento Water Project at which point water demand again began to decrease leading into the 2012-
2015 drought period. The reduction of potable water demand became more pronounced during the 2012–
2015 drought and subsequent State and local drought response regulations. During the latter years of the
drought, the City implemented significant conservation measures and water use reduction requirements
consistent with statewide drought response efforts. Unlike prior drought periods, reductions in potable water
demand observed during and after the 2012–2015 drought appear to have been more permanent in nature.
Since approximately 2010, and particularly following the 2012–2015 drought, the City’s total potable water
demand has generally leveled off and has not increased at a rate directly proportional to population growth.
Although the City has continued to exper ience population growth over this period, increases in water
demand attributable to additional population have largely been offset by ongoing improvements in water
use efficiency within the City’s existing customer base. These improvements include installation of low-flow
plumbing fixtures and appliances, increased use of water-efficient landscaping and irrigation systems,
updated building and landscape development standards, implementation of water conservation programs,
and lasting changes in customer water use behavior. As a result, both per capita and overall potable water
demand have remained comparatively low and stable relative to historical pre -drought conditions.
Over the past 30 years, from 1996 through 2025, annual potable water demand in the City has ranged from
a high of 6,416 acre-feet in 2007 to a low of 4,520 acre-feet in 2016, a difference of more than 1,895 acre-
feet. In contrast, over the most recent ten-year period from 2016 through 2025, annual potable water
demand has ranged from a high of 5,019 acre-feet to a low of 4,520 acre-feet, a difference of approximately
499 acre-feet. This substantially narrower range in annual demand indicates that post -drought potable
water use has become more stable and less variable than historical pre -drought demand conditions. The
reduced variability in water demand also suggests that a significant portion of the conservation achieved
during and following the 2012–2015 drought represents lasting efficiency improvements and permanent
changes in water use behavior rather than temporary drought-response reductions alone. As a result, future
drought-related conservation measures may yield smaller reductions in overall potable water demand tha n
were achieved during previous drought periods when baseline water use levels were substantially higher.
4.4 Current Water Demand
Current potable water demand within the City is primarily comprised of residential, commercial, institutional,
industrial, irrigation, and distribution system water loss sectors. As shown in Table 4-1: 2025 Potable Water
Use by Sector, single-family residential demand represents the largest individual water use sector within
the City, accounting for approximately 40 percent of total potable water demand in 2025. Commercial,
industrial, and institutional uses collectively account for approximately 2 3 percent of total demand, while
multi-family residential demand represents approximately 24 percent of total potable water demand.
Dedicated landscape irrigation accounts for approximately 11 percent of total potable water demand.
Distribution system water loss accounted for approximately 7 percent of total potable water demand in
2025. Water loss includes both real losses, such as leakage from pipelines and appurtenances, and
apparent losses associated with meter inaccuracies or data handling issues. Additional discussion
regarding the City’s water loss auditing program and distribution system losses is provided in Section 4.6
of this chapter.
TABLE 4-1: 2025 POTABLE WATER USE BY SECTOR
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2025 Potable Water Use Sector
Single-
Family
Multi-
family
Commercial,
Industrial,
and Institutional
Dedicated
Irrigation
Distribution System
Water Loss
Total
Volume
Water Use (AFY) 1,917 1,193 1,033 306 384 4,833
% of 2025 total: 40% 25% 21% 6% 8% 100%
Source: City of San Luis Obispo Utilities Department, 2026.
4.5 Future Water Demand Projections
Future potable and non-potable water demand projections were developed for the 2025 UWMP planning
horizon to support long-term water supply reliability analysis, infrastructure planning, drought preparedness,
and compliance with the UWMP Act. The demand pr ojections presented in this section are used for long-
term planning purposes and are intended to evaluate whether the City’s existing and planned supplies are
sufficient to meet projected demands through 2050.
Future potable water demand projections were developed using the population methodology described in
Section 3.6 and the City’s long-term potable water demand planning value of 117 gallons per capita per
day (gpcd). This approach is consistent with the General Plan and WWE and provides a conservative basis
for evaluating long-term water supply reliability. The 117 gpcd planning value is based on the City’s
confirmed SB X7-7 water use target and is higher than the City’s current estimated potable water use o f 87
gpcd. Use of the higher 117 gpcd value provides a buffer for potential changes in future water use patterns,
land use, climate, hydrologic conditions, regulations, customer behavior, and other factors that may affect
demand over the multi-decade UWMP planning horizon.
The City’s long-term potable water demand projections are based on the population methodology described
in Section 3.6 and the City’s 117 gpcd water demand planning value. The projections are not reduced
further to separately quantify future water savings from plumbing codes, appliance standards, building
standards, landscape ordinances, transportation plans, or other adopted conservation -related policies. This
approach is conservative because the 117 gpcd planning value is higher than current estimated pot able
water use and does not assume additional future demand reductions beyond those already reflected in
existing customer water use patterns and the City’s long-term planning methodology. Applicable codes,
standards, ordinances, and plans that support ongoing water use efficiency include the California Plumbing
Code, California Green Building Standards Code, the Model Water Efficient Landscape Ordinance and City
landscape requirements, the City’s water waste prevention provisions, and the General Plan and WWE.
The long-term demand projections shown in this section are not intended to represent expected customer
water use during upcoming single-year assessment periods or the five-year drought risk assessment
outlined in this UWMP. Near-term operational reliability analyses are conducted for a different purpose and
use more current information, including recent actual water use, current population estimates, recent
seasonal demand patterns, dry-year adjustments, source availability, and known or anticipated
infrastructure constraints. These assumptions inform the City’s Water Projection Model, which is used to
assess near-term water supply availability and evaluate whether actual or anticipated conditions may result
in a shortage. This distinction is important as it allows the City to preserve a conservative long-term demand
forecast for General Plan consistency and multi-decade planning, while using more precise near-term
information when evaluating actual or anticipated shortage conditions.
The City’s projected water demands include anticipated residential and non-residential growth within the
City’s urban services area, including projected water use associated with lower-income housing identified
in the City’s Housing Element. California Water Code Section 10631.1(a) requires urban water suppliers to
include projected water use for single-family and multifamily residential housing needed for lower-income
households, as identified in the housing element of any city, county, or city and county within the supplier’s
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service area. The City’s adopted Housing Element identifies the City’s 6th Cycle Regional Housing Needs
Allocation, including 825 very-low-income (inclusive of 412 extremely-low-income) units and 520 low-
income units, for a total of 1,345 lower-income housing units. For informational purposes and consistency
with California Water Code Section 10631.1(a), the estimated water demand associated with lower-income
housing is approximately 430 acre-feet per year.6
Because the City’s water demand projections are based on projected population within the planning
timeframe through 2050, water demand associated with lower-income housing is included within the City’s
overall water demand forecast. The estimated annual 430 acre-feet of water demand for lower-income
residential units is included in single and multi-family residential water demand estimates presented in Table
4-2: Projected Future Potable Water Demand by Year below. This estimate demonstrates the scale of
projected water use associated with lower-income housing and confirms that such demand is included
within the City’s overall projected residential water demand.
Projected future potable water demand by sector is presented in Table 4-2: Projected Future Potable Water
Demand by Year below, with non-potable water demand shown separately in Table 4-3: Projected Future
Non-Potable Water Demand by Sector.
TABLE 4-2: PROJECTED FUTURE POTABLE WATER DEMAND BY YEAR
Potable Water Demand (Acre-Feet) by Year
2030 2035 2040 2045 2050
Single Family 2,804 2,973 3,125 3,285 3,452
Multi-Family 1,744 1,850 1,944 2,043 2,148
Dedicated Irrigation
/ Landscape 447 474 498 523 550
Commercial 1,381 1,464 1,539 1,617 1,700
Institutional 84 89 93 98 103
Industrial 47 50 52 55 58
Distribution System
Water Loss 562 596 627 659 692
Total Potable
Water Demand 7,068 7,496 7,879 8,281 8,703
Notes: Individual demand categories are displayed as whole numbers for readability; however, underlying
calculations are performed using values carried to additional decimal places. As a result, totals may not equal the
exact sum of the displayed values due to rounding.
TABLE 4-3: PROJECTED FUTURE NON-POTABLE WATER DEMAND BY SECTOR
Non-Potable Water Demand (Acre-Feet) by Year
2030 2035 2040 2045 2050
Landscape 293 343 393 443 493
Golf Course 33 33 33 33 33
6 Estimated water demand is based on 1,345 lower-income housing units, an average household size of 2.44 persons
per household, and the City’s conservative long-term planning assumption of 117 gallons per capita per day.
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Construction Water
Program Use 12 12 12 12 12
Water/Sewer Utility
Use 0.02 0.02 0.02 0.02 0.02
Total Non-Potable
Water Demand 338.02 388.02 438.02 488.02 538.02
Notes: Individual demand categories are displayed as whole numbers for readability; however, underlying
calculations are performed using values carried to additional decimal places. As a result, totals may not equal the
exact sum of the displayed values due to rounding.
4.6 Distribution System Water Loss
Senate Bill 555 (2015) requires retail water suppliers in California with more than 3,000 service connections
or annual deliveries exceeding 3,000 acre-feet to complete an annual water loss audit of their distribution
system. The standardized audit must be validated by a certif ied water loss auditor to ensure consistency
and accuracy in reporting. The City submitted its first validated water loss audit to the DWR in 2017 for
Calendar Year 2016 and has continued to complete annual audits thereafter.
The City performs annual water loss audits using the methodology outlined in the Water Audits and Loss
Control Programs Manual (M36) published by the American Water Works Association (AWWA). Water loss
audits for reporting years 2020, 2021, and 2022 were completed on a calendar -year basis. Following
submittal of the calendar year 2022 audit, the City transitioned to a fiscal-year reporting basis to better align
with internal financial, billing, and operational data systems. As a result of this transition, t he City has
included six water loss audits in this UWMP rather than five: Calendar Years 2020, 2021, and 2022, followed
by Fiscal Years 2022-23, 2023-24, and 2024-25. The Calendar Year 2022 and Fiscal Year 2022-23 audits
partially overlap due to the transition in reporting basis; however, including both audits provides a complete
and transparent record of the City’s submitted audits and ensures continuous coverage of the applicable
five-year period. Due to the change in reporting periods, there is no standa lone water loss audit
corresponding specifically to Calendar Year 2023. The change in reporting periods does not affect the City’s
overall evaluation of system water loss trends or compliance with State reporting requirements.
The results of the annual water loss audits are submitted to the State to comply with water loss reporting
requirements enacted pursuant to California Water Code Section 10631.1. In addition to the audit itself, the
City reports actions taken to improve the accuracy and validity of water loss data, reduce apparent losses,
and reduce real losses within the potable water distribution system.
Water losses can occur as the result of a variety of factors including , but not limited to, pipeline leaks,
service line leaks, meter inaccuracies, data handling errors, and storage facility overflows. Water loss is
distinct from unbilled authorized consumption, which includes approved operational uses of water that are
not billed by the City, such as mainline flushing, fire flow testing, water quality sampling, and treatment
process water. Losses that are neither billed nor metered are classified as appare nt losses and include
unauthorized consumption, metering inaccuracies, and systematic data handling errors. Common
examples of water loss and unbilled authorized consumption are summarized in
Table 4-4: Common Water Loss & Unbilled Consumption Types.
Examples of Water Loss & Unbilled Authorized Consumption Causes
Water Loss Mainline & Service Line
Leakage Meter Inaccuracies Data Handling
Errors
Overflow of
Storage Tanks
Unbilled
Authorized
Consumption
Treatment Plant and
Distribution System
Process Water
Mainline Flushing Fire Flow Testing Water Quality
Testing
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Water loss values noted in the UWMP may vary depending on the purpose and scope of the calculation.
The validated AWWA water loss audit values shown in
Table 4-4 are used for State water loss reporting and focus on the potable distribution system. Other values
presented in the UWMP may be developed for water demand, supply accounting, or operational planning
purposes and may include additional volumes such as water treatment plant process water, operational
uses, or losses occurring before treated water enters the distribution system. As a result, water loss values
presented in different sections of this UWMP should be interpreted in the context of the specific calculation
being used.
TABLE 4-4: COMMON WATER LOSS & UNBILLED CONSUMPTION TYPES
The AWWA M36 methodology utilizes the Infrastructure Leakage Index (ILI) as a primary performance
metric for evaluating real, or physical, water losses within a distribution system. The ILI is a unitless
benchmarking metric defined as the ratio of Current Annual Real Losses (CARL) to Unavoidable Annual
Real Losses (UARL). This metric allows comparison of leakage performance between water systems while
accounting for differences in system size, pressure, number of service connections, and pipeline length.
Unavoidable losses represent the theoretical minimum level of leakage expected in a distribution system
based on its physical characteristics and background leakage assumptions. A well -performing system
generally has an ILI value below 3.0, indicating that real losses are less than three times the u navoidable
leakage level, although interpretation of ILI values may vary depending on system characteristics and
operating conditions. The City’s average ILI for the most recent six water loss audits is 1.8, as shown in
Table 4-5: Water Loss Audit Data and Results.
TABLE 4-5: WATER LOSS AUDIT DATA AND RESULTS
Year
Billed
Authorized
Consumption
Unbilled
Authorized
Consumption
Apparent
Losses Real Losses
Infrastructure
Leakage
Index (ILI)
Real Water
Loss,
Gallon per
Connection
per Day
CY 2020 4,347.37 79.64 113.23 276.56 1.0 15.5
CY 2021 4,460.14 11.71 114.73 430.75 1.6 23.6
CY 2022 4,354.55 23.48 110.90 582.72 2.1 31.1
Examples of Water Loss & Unbilled Authorized Consumption Causes
Water Loss Mainline & Service Line
Leakage Meter Inaccuracies Data Handling
Errors
Overflow of
Storage Tanks
Unbilled
Authorized
Consumption
Treatment Plant and
Distribution System
Process Water
Mainline Flushing Fire Flow Testing Water Quality
Testing
Examples of Water Loss & Unbilled Authorized Consumption Causes
Water Loss Mainline & Service Line
Leakage Meter Inaccuracies Data Handling
Errors
Overflow of
Storage Tanks
Unbilled
Authorized
Consumption
Treatment Plant and
Distribution System
Process Water
Mainline Flushing Fire Flow Testing Water Quality
Testing
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FY 2023 4,099.50 23.13 83.12 707.43 2.6 39.1
FY 2024 4,294.48 14.16 86.92 368.34 1.3 19.4
FY 2025 4,447.78 11.66 89.98 561.86 2.0 29.3
Six-Year Average 1.8 26.3
NOTES:
1. 2020-2022 reports utilized a calendar year reporting period. Calendar reporting year was changed to fiscal year after
2022, which results in 2024 report being next sequential reporting period after the 2022 report.
Another metric utilized to evaluate water loss performance is gallons per connection per day (gal/conn/day),
which is used by the State Water Resources Control Board as a primary measure of system water loss
performance. The City’s average water loss in gal/conn/day is generally comparable to values reported by
other California urban water suppliers.
The State Water Resources Control Board has developed an economic model to establish system-specific
water loss performance standards for each urban retail water supplier. The model estimates the level of
leakage reduction that is economically feasible based on system characteristics and a lifecycle cost-benefit
analysis conducted over a 30-year planning horizon. Urban water suppliers are required to comply with
their assigned standards by 2028. The City’s current water loss standard is 21.0 gal/conn/day. T his
standard is based on the State’s economic model with an adjustment applied to account for data uncertainty
and system-specific conditions using water loss audit data submitted for the period 2017 through 2020.
The City plans to continue reducing water losses and maintaining compliance with State requirements
through implementation of Advanced Metering Infrastructure (AMI), improved testing and calibration of
large meters, continued leak detection efforts, replac ement of aging infrastructure, and ongoing system
maintenance programs. Complete water loss audit reports for the five-year reporting period are provided in
Appendix D.
CHAPTER 5: SB X7-7 BASELINES, 2020 TARGETS, AND 2025
REPORTING
5.1 Introduction and Regulatory Context
The Water Conservation Act of 2009 (SB X7-7) required urban retail water suppliers to establish baseline
water use, adopt urban water use reduction targets, and demonstrate compliance with those targets by
2020. The legislation established a statewide goal of reducing urban per capita water use by 20 percent by
2020, along with an interim target for 2015. The City established its SB X7-7 baseline and water use targets
as part of prior Urban Water Management Plans and reported compliance in the 2020 UWMP. Co nsistent
with current UWMP requirements, this chapter summarizes the City’s previously established baseline and
target values and confirms continued compliance with SB X7-7. This chapter also provides context for the
transition from SB X7-7 requirements to the State’s current Urban Water Use Objective (UWUO) framework.
5.2 Baseline and Target Summary
The City established its SB X7-7 urban water use target using Target Method 3, as explained in DWR’s
Methodologies for Calculating Baseline and Compliance Urban Per Capita Water Use . Under this method,
the target is based on the per capita water use goal assigned to the applicable hydrologic region, and urban
retail water suppliers may adopt a target equal to 95 percent of that regional value.
The City of San Luis Obispo is located within the Central Coast Hydrologic Region, which has relatively low
per capita water use compared to other regions of the State due to its coastal climate and historically
efficient water use patterns. Target Method 3 provides a regionally appropriate benchmark and allows for
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consistency among suppliers within the same hydrologic region.
As documented in the City’s prior UWMPs, the City selected Target Method 3 after evaluating all state-
approved methodologies. The City determined that baseline-based methods were not appropriate due to
long-standing investments in water conservation and already reduced per capita water use, which would
have made additional reductions from historical baseline conditions difficult and incredibly costly to achieve.
Consistent with Water Code Section 10608.20(g) and DWR guidance, the City continues to rely on the
previously established baseline and target values and has not modified its selected target method for the
2025 UWMP. The City’s baseline and target values are summarized in Table 5-1.
TABLE 5-1: SB X7-7 BASELINE AND TARGET SUMMARY
Metric Value
10-Year Baseline (1997-2006) 123 GPCD
5-Year Baseline (2004-2008) 124 GPCD
2015 Interim Target 120 GPCD
2020 Target 117 GPCD
2020 Reporting Year 94 GPCD
2025 Reporting Year 87 GPCD
5.3 SB X7-7 Compliance and 2025 Reporting
As documented in Table 5-1, the City met, exceeded, and continues to exceed its SB X7-7 water use
reduction target. The adopted target of 117 gallons per capita per day (gpcd) was achieved in 2020, with
an actual 2020 per capita water use of 94 gpcd. Since that time, the City has continued to maintain per
capita water use below the adopted target, with its most recent data from 2025 indicating a per capita water
use of 87 gpcd.
This level of performance reflects the City’s long-standing commitment to water conservation, including
implementation of demand management measures, system improvements, and sustained reductions in per
capita water use during and following recent drought periods. These efforts have resulted in consistently
lower per capita water use, and current demand trends remain aligned with these reduced levels.
For the 2025 UWMP, the City evaluated whether any changes since the 2020 UWMP would affect its
ongoing SB X7-7 compliance status. This evaluation included review of service area boundaries, population
data, and water use calculation methodologies. No significant changes were identified that would require
recalculation of baseline conditions or the 2020 target. Accordingly, the previously established target values
remain valid for 2025 reporting purposes.
While SB X7-7 established water use reduction requirements through 2020, ongoing water use efficiency
is now governed by State regulations establishing Urban Water Use Objectives (UWUO). The City will
continue to monitor water use trends and implement demand management measures, as described in
Chapter 9, to support long-term water use efficiency and compliance with current regulatory requirements.
Maintaining compliance with SB X7-7 and UWMP requirements is also necessary to ensure continued
eligibility for State water-related grants and loans. The City’s demonstrated compliance supports continued
eligibility for such funding opportunities. Supporting data for this chapter is provided in the UWMP Submittal
Tables within Appendix A.
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CHAPTER 6: NORMAL-YEAR WATER SUPPLY CHARACTERIZATION
6.1 Introduction
This chapter describes the City’s water supply portfolio and establishes the supply assumptions used to
evaluate water service reliability in Chapter 7. The chapter identifies the City’s existing and planned potable
and non-potable supplies, summarizes the legal, operational, and infrastructure basis for those supplies,
and presents projected normal-year supply availability through the UWMP planning horizon (2025-2050).
The City’s water supply portfolio includes local surface water supplies, planned groundwater production,
and recycled water. Potable supplies include Salinas Reservoir, Whale Rock Reservoir, Nacimiento
Reservoir, and groundwater. Recycled water is used for approved non-potable purposes and offsets
potable water demand where recycled water service is available and authorized.
The supply quantities presented in this chapter are planning values used for UWMP analysis. Actual annual
use from each source may vary based on hydrologic conditions, reservoir storage, water quality,
conveyance availability, treatment capacity, infrastructure conditions, regulatory requirements, seasonal
demand, and operational needs. Current-year use by source may also differ from normal-year supply
availability when temporary infrastructure limitations or operational constraints affect a supply, such as the
recent Nacimiento transmission system outage.
The chapter also describes the City’s water supply modeling and yield assessment methods, including the
combined safe annual yield analysis for Salinas and Whale Rock Reservoirs, Nacimiento Reservoir
reliability considerations, planned groundwater supply assumptions, and recycled water availability. These
analyses provide the basis for the projected normal-year supply volumes presented in this chapter and the
normal-year, single dry-year, multiple dry-year, and drought risk assessment analyses presented in Chapter
7.
6.2 Water Supplies
6.2.1 Salinas Reservoir
Salinas Reservoir (also known as Santa Margarita Lake) is
located on the upper Salinas River, approximately nine miles
southeast of the community of Santa Margarita. The project
was originally built by the Federal War Department to ensure
an adequate water supply for Camp San Luis Obispo, as well
as the City of San Luis Obispo. The dam and appurtenances were declared surplus by the War Department
on April 14, 1947 and the U.S. Army Corps of Engineers assumed responsibility for the facilities. On July
11, 1947, the Corps entered into an agreement with the San Luis Obispo County Flood Control and Water
Conservation District (District) for the operation and maintenance of the dam and related facilities. The City
has an agreement with the Corps for use of the reservoir, as well as a water rights permit to divert water
from the Salinas River for storage within the reservoir. The City is the only recipient of water stored in
Salinas Reservoir.
Immediately following construction of the Salinas Dam, the reservoir had an estimated storage capacity of
24,000 acre-feet, surface area of 793 acres, and a drainage area of 112 square miles. As a result of siltation
since the original construction, the reservoir capacity has been reduced to 22,508 acre-feet. A 2024 analysis
conducted by the County of San Luis Obispo indicates that the siltation rate at Salinas Reservoir is
approximately 46 acre-feet per year.
Salinas Reservoir
✓Potable Water Supply
✓Fills and Spills Frequently
✓Exclusively Used by City of SLO
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Operations and Distribution
Water is conveyed from Salinas Reservoir
through 9.2 miles of 24-inch diameter
reinforced concrete pipe to a three-million-
gallon forebay at the Santa Margarita booster
pump station near the northerly base of Cuesta
Grade adjacent to Highway 101. The pipeline
is designed to flow by gravity from the
Reservoir to the forebay when the lake level is
above the elevation of 1,267 feet. The pump
station at the base of the dam, consisting of
two horizontal centrifugal pumps, is capable of
maintaining the rated flow of 12.4 cubic feet
per second (cfs) when the water surface
elevation falls below 1,267 feet. Three
electrically driven, horizontal centrifugal
pumps at the Santa Margarita booster station
pump water through 6,810 feet of 24-inch
diameter reinforced concrete pipe to the
entrance portal of the Cuesta Tunnel, which
runs 5,327 feet through the mountains near
Cuesta Grade. From the outlet portal of the
tunnel, water is conveyed through an 18-inch diameter steel pipeline a distance of 5,133 feet to the City's
turnout point. From the turnout, an 18-inch diameter pipe runs 4,180 feet to the site of Reservoir #2 on
Stenner Creek Road. From there, a pipeline that varies from 24-inches to 30-inches in diameter conveys
the water by gravity to the water treatment plant 5,930 feet downstream.
The operation and maintenance of the dam and water conveyance system (to the City’s turnout) are the
responsibility of San Luis Obispo County Flood Control and Water Conservation District. The City pays all
operating, maintenance, and capital costs associated with the reservoir and transmission system (excluding
costs associated with recreational activities at the lake, which are funded by the County).
While the Salinas delivery pipeline is over 80 years old, most of the line is operated under low pressure, as
the largest segment running from the reservoir to the booster pump station’s forebay is gravity fed from the
reservoir. Only a small segment of pipe from the booster pump station to the Cuesta Tunnel is under
pressure from an on-site pump station, however, this section opens into the Cuesta Tunnel, decreasing the
risk of failure due to over pressurization or transient pressure surges. The Salinas pipeline has continually
provided the City with water deliveries, with a limited number of short-duration outage periods occurring
since its construction.
6.2.2 Whale Rock Reservoir
Whale Rock Reservoir is located along Old Creek approximately one-half mile east of the community of
Cayucos. The project was planned, designed, and constructed under the supervision of DWR. Construction
of the dam and conveyance infrastructure took place between October 1958 and April 1961. The reservoir
is jointly owned by the City, the California Men's Colony, and Cal Poly who collectively form the Whale Rock
Commission, which is responsible for operation and administration of the dam, reservoir, pipeline, pump
stations, and associated water deliveries. Day-to-day operation of the facility is provided by the City with
financial contributions towards operations and maintenance coming from all three commission member
agencies. When considering storage rights and ongoing cost coverage, the City owns 55.05 percent of the
water storage rights at the reservoir and is responsible for an equivalent percentage of costs . The remaining
water storage rights and costs are apportioned between the two State agencies with Cal Poly owning 33.71
SALINAS DAM SPILLWAY, FEBRUARY 2019
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percent and the California Men’s Colony owning the remaining 11.24 percent.
Operation and Distribution
Whale Rock Reservoir is formed by an earthen dam
and was able to store an estimated 40,662 acre-feet of
water at the time of construction. The dam is 266 feet
tall with a crest length of 850 feet and crest width of 30
feet. The top of dam elevation is 232.2 feet. The
Reservoir covers an area of 600 acres. The maximum
storage capacity as of 2025 is 38,967 acre-feet. Over
the life of the Whale Rock Reservoir and dam, the lake
has filled to capacity and spilled 14 times, last spilling
in 2024.
The project facilities consist of a 30-inch pipeline, two pumping stations, over two miles of trails and a fishing
access area, a maintenance facility and office, and a structure used as the Whale Rock Reservoir
Supervisor’s residence. City staff are responsible for ongoing maintenance and operation of this
infrastructure, including the inlet and outlet structures, reservoir monitoring instrumentation, access roads,
daily reservoir level readings and climatological data, reservoir patrol and security, pipelines and pumping
stations, water meters, cathodic protection systems, and other water storage and distribution-related
assets. Staff also monitor public access to the lake and perform watershed protection-related work.
Delivery turnouts from the pipeline exist for several private property owners adjacent to the reservoir, the
Cayucos Water Treatment Plant, the California Men’s Colony’s water treatment plant, and the City's water
treatment plant, which treats water for both the City and Cal Poly. In addition, water can be delivered to the
Dairy Creek Golf Course under terms of
an agreement between the California
Men’s Colony and the County of San Luis
Obispo.
The Whale Rock pipeline is
approximately 17 miles long, connecting
the reservoir to the member agencies,
and terminating at the City's Water
Treatment Plant. The design capacity of
the pipeline is 18.94 cubic feet per second
(approximately 8,500 gallons per minute).
The line consists of modified pre-stressed
concrete cylinder pipe at most locations.
Cement mortar lined steel pipe is used at
creek crossings and junctions. The
pipeline has surge protection consisting
of eight-inch, globe type, diaphragm-
actuated pressure relief valves and surge tanks, which protect the line from excessive pressure surges.
The cathodic protection system consists of sacrificial anodes and test stations located in areas subject to
galvanic corrosion. Previous inspections made during routine maintenance and repairs indicate the pipeline
is in good condition given its age.
Two pump stations transmit the water through the pipeline to member agencies. The first pump station is
located in Cayucos at Chaney Way (elevation 44 feet). The second station is located near Camp San Luis
Obispo, approximately six miles southeast of Morro Bay (elevation 181 feet). Each station has five -200
horsepower pumps capable of delivering various flow rates requested by member agencies. Whale Rock
generally uses one to three of the five available pumps, providing resiliency in case of infrastructure failure.
Upgrades to both pump stations, which included the addition of two pumps at each station, were completed
in August 1993. Whale Rock staff are currently under contract with a design engineer to complete a study
WHALE ROCK RESERVOIR, MAY 2026
Whale Rock Reservoir
✓Potable Water Supply
✓Low Annual Evaporation
✓Superior Water Quality
✓Reliable During Extended Drought
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of the condition of the existing pump stations, which will inform a future project to modernize and upgrade
the stations.
Spillway Inspections
In 2018, the City contracted with HDR Engineering, Inc. for inspection and assessment of the 850-foot long
Whale Rock Dam spillway. The investigation included:
1. Review of design, construction, inspection, analysis, operation and maintenance, and geologic
information, as provided by City.
2. Detailed visual, non-destructive inspection of the spillway slabs and walls from upstream of the
spillway crest to downstream of the stilling basin.
3. Video/camera inspection of accessible outfall drains and heel drains.
4. Geologic inspection of foundation material adjacent to the spillway.
5. Evaluation of original spillway design versus a modern spillway design.
6. Evaluation of operations, inspection, and surveillance practices.
7. Evaluation of performance of previous repairs.
A report was completed in March 2019 with recommendations
including maintenance and repair activities for the drainage
system and further engineering investigations. The City and
its Whale Rock partners, Cal Poly and the California Men’s
Colony, implemented repairs and a subsequent final
inspection, as recommended by DSOD, and the spillway is
functioning as designed.
Operating Agreements
Several agreements establish policies for the operation of the
Whale Rock system and actions of the member agencies. A
brief description of the existing agreements follows:
1. Agreement for the construction and operation of the
Whale Rock Project, 1957, set forth the project's
capital cost distribution to the member agencies.
2. A supplemental operating agreement, 1960,
established the Whale Rock Commission and
apportioned the operating costs.
3. Downstream water rights agreement (original 1958
agreement was amended and replaced with a new
agreement in April 1996) established water
entitlements for adjacent and downstream water
users. The downstream water users (Cayucos Area
Water Organization or CAWO) affected by this
agreement consist of three public water purveyors
and the cemetery. In addition to the agencies, water entitlements were identified for separate
downstream landowners (Error! Reference source not found.).
4. A decision and order by the Fish and Game Commission of the State of California, October 24,
1964, required the Whale Rock Commission to stock the reservoir with 17,500 rainbow trout
(between six and eight inches long) each year. The State Department of Fi sh and Game has
directed that no fish be planted in the reservoir to protect the existing fish population in the reservoir
(landlocked steelhead).
Downstream Water
Users
Allocation
(AF/Y)
Cayucos Area Water
Organization 600
Paso Robles Beach
Water Association 222
Morro Rock Mutual
Water Company 170
County Water District
#10A 190
Cayucos-Morro Bay
Cemetery District 18
Mainini 50
Ogle 14
Total Downstream
Entitlement: 664
TABLE 6-1: WHALE ROCK RESERVOIR
DOWNSTREAM ENTITLEMENTS
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5. Superior Court decision #36101, 1977, required the Whale Rock Commission to allow public entry
to the reservoir for fishing. In 1981, construction was completed on access trails and sanitary
facilities at the reservoir, and public fishing began at the lake .
6. An agreement for water allocation and operational policy between the agencies forming the Whale
Rock Commission. The agreement established accounting procedures to allow each agency to
carry over excess or deficit water each year. The operating policies we re most recently amended
in 2014 to allow agencies to utilize their water supplies in the reservoir as needed by their agency.
7. An agreement between the Whale Rock Commission and the California Men's Colony, 1990, to
establish maintenance and operation criteria for the Chorro Booster pumps. The Chorro Booster
pumps were installed by the Commission on the California Men's Colony tur nout from the Whale
Rock line to reduce system pressures required to provide full flow to the California Men's Colony
water treatment plant. Pump station maintenance, according to the agreement, is the responsibility
of the California Men's Colony.
8. An agreement between the Whale Rock
Commission and the County of San Luis Obispo
for connection to the Whale Rock pipeline, 1995,
allowed a pipeline connection to deliver water to
the Dairy Creek Golf Course. Typically, the golf
course uses reclaimed water from the California
Men’s Colony Wastewater Treatment Plant.
Water from Whale Rock Reservoir can be
delivered when reclaimed water is not available
under the terms of the agreement.
9. A consent to common use agreement, 1996,
between the Whale Rock Commission and the
County of San Luis Obispo. The agreement
allowed the installation of the State Water
pipeline at seven locations within the existing
Whale Rock pipeline easement.
10. An agreement, updated in 2018, for exchange of
water between the City of San Luis Obispo and
the San Luis Obispo County Service Area No.
10A. The agreement allows for the exchange of
up to 50 acre-feet per year of Nacimiento water
for water from Whale Rock Reservoir.
WHALE ROCK RESERVOIR, MARCH 2024
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6.2.3 Nacimiento Reservoir
In 1959, the San Luis Obispo Flood Control and Watershed Protection District entered into an agreement
with Monterey County Flood Control and Water Conservation District (now Monterey County Water
Resources Agency) to secure rights to 17,500 acre-feet of water per year from Nacimiento Reservoir.
Nacimiento Reservoir is located entirely within San Luis Obispo County, California (County), and was built
by Monterey County Flood Control and Water Conservation District who continues to control reservoir
ownership and operations. Nacimiento Reservoir has a storage capacity of 377,900 acre-feet and serves
the purpose of abating seawater intrusion in the groundwater aquifers of the Salinas River Valley. The
Nacimiento Reservoir also provides flood protection
and is a source of water supply for groundwater
recharge for the Salinas Valley. 1,750 AFY of the
County’s entitlement have been designated for uses
around the lake, leaving 15,750 AFY for allocation to
other areas within the County of San Luis Obispo.
The “dependable yield” from Nacimiento Reservoir is
the contractual amount of water that the City has rights
to from Nacimiento Reservoir. The original amount
contracted for was 3,380 acre-feet per year.
Engineering studies, environmental impact reports,
dependable yield analyses, and preliminary design
reports were undertaken in an effort to meet the various water needs within the County. In 2004, the County
requested interested agencies to approve the contractual agreements for participation in the Nacimi ento
Project. The four initial project participants included the cities of San Luis Obispo and Paso Robles, the
Atascadero Mutual Water Company, and the Templeton Community Services District. All of these agencies
executed participation agreements with San Luis Obispo County for entitlements of water which totaled
9,630 acre feet. On June 29, 2004, the City Council authorized participation in the Nacimiento Water Project
for the delivery of the original 3,380 acre-feet of water. In 2004, the County Service Area 10A in Cayucos
became a project participant (25 AFY).
The County began construction in 2007 on a 45 -mile pipeline project to deliver water from the Nacimiento
Reservoir to participating agencies and cities. The facilities consist of a multi-port intake structure, three
pump stations, three storage tanks, 45 miles of pipeline, four turnouts, a control center, and a Supervisory
Control and Data Acquisition (SCADA) and project control system. The Project budget was $176 million,
including design, construction, construction management, environmental permitting, an d right-of-way
acquisition. Pipeline construction and related water delivery facilities were completed in the fall of 2010 with
water deliveries to the City beginning in January of 2011.
In March 2016, the City Council approved the purchase of an additional 2,102 AFY from Nacimiento
Reservoir to bolster the City’s water supply portfolio. This addition brought the City’s total allocation to 5,482
AFY. With uncertainty of future climatic conditions, regulation and aging infrastructure, the additional supply
of Nacimiento water to the City’s portfolio reduces pressure on use of water supplies in the Whale Rock
and Salinas reservoirs. This additional volume would serve to extend these stored supplies in anticipation
of and during future critical water shortage periods.
Operations and Distribution
San Luis Obispo County operates, maintains, and administers capital improvement projects for the water
delivery system from Nacimiento Reservoir to participating agencies. The Nacimiento Project Commission
provides oversight of project operations, maintenance, and the project budget. The Commission is made
up of representatives from each of the four founding agencies’ governing boards and a County
Representative who is a member of the County Board of Supervisors who also sits on the Board of Directors
for the Flood Control District.
Nacimiento Reservoir
✓Potable Water Supply
✓5,482 acre-feet Available Annually
✓Contractual Supply
✓Reliable During Extended Drought
✓Currently Impacted by Broken Pipeline
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6.2.4 Groundwater
The principal source of groundwater for the City is the San Luis Obispo Valley Groundwater Basin (Basin).
The Basin is oriented in a northwest-southeast direction and is composed of unconsolidated or loosely
consolidated sedimentary deposits. It is approximately 14 miles long and 1.5 miles wide and covers a
surface area of about 12,700 acres, or 19.9 square miles. The Basin is bounded on the northeast by the
relatively impermeable bedrock formations of the Santa Lucia Range and on the southwest by the
formations of the San Luis Range and the Edna fault system. The bottom of the Basin is defined by the
contact of permeable sediments with the impermeable bedrock Miocene-aged and Franciscan Assemblage
rocks. The Basin is commonly referenced as being composed of two distinct valleys, with the San Luis
Valley in the northwest providing water to the City of
San Luis Obispo and the Edna Valley in the southeast
providing water to unincorporated areas of the county
and large agricultural operations.
Groundwater has historically been an intermittent
source of supply for the City. The City’s major sources
of water were groundwater and surface water from
local creeks until 1944, when the City began using
water from Salinas Reservoir. In 1943, the City pumped 1,380 acre-feet of groundwater, and groundwater
was used again during the summer of 1948, when 440 acre -feet was pumped. From that point until 1989,
most groundwater use within the City was associated with private agricultural use, with limited municipal
use for domestic consumption. With the onset of the 1986 drought and declining surface water supplies,
the City activated groundwater wells in 1989 to help meet water demand. From 1992 through 2015, the City
ceased use of its remaining wells for a variety of reasons, primarily related to reduced overreliance on
groundwater and localized contamination issues. Most recently, in April 2015, the City stopped utilizing its
last groundwater supply well, the Pacific Beach Well on Los Osos Valley Road, due to more stringent State
regulations for hexavalent chromium.
In the 2010 update of the General Plan WWE, the City removed groundwater from the water supply
calculation used as a basis for meeting long-term water demands. This approach was continued in the 2015
UWMP and 2020 UWMP because the City was not actively using groundwater as a regular municipal supply
and because water quality, infrastructure, and supply reliability considerations limited the City’s ability to
rely on groundwater for long-term planning purposes. As a result, previous UWMP planning did not include
groundwater as an available long-term supply source.
TABLE 6-2: SURFACE WATER RESERVOIR CHARACTERISTICS
Reservoir Watershed Size
(Square Miles)
Storage Capacity
(Acre-Feet)
Average Annual
Precipitation (Inches)
Average Annual
Evaporation (Inches)
Salinas 112.0 22,508 22.1 85.4
Whale Rock 20.3 38,967 18.7 61.6
Nacimiento 361.5 377,900 35-55 -
Notes:
1. Average annual precipitation and evaporation levels are based on the verified hydrologic data from the City’s safe
annual yield mode, 2018. See Appendix IV.
2. Due to the size of the Nacimiento Reservoir watershed area, average precipitation varies significantly throughout the
watershed area. Evaporation averages for Nacimiento Reservoir are not currently identified.
Groundwater Supply
✓Potable Water Supply
✓Estimated to be Available in FY 2027-28
✓Safe Annual Yield of 700 Acre-Feet/Year
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Since preparation of the 2020 UWMP, the City has gained substantial additional information regarding the
San Luis Obispo Valley Groundwater Basin through implementation of the Sustainable Groundwater
Management Act (SGMA), preparation and adoption of the San Luis Obispo Valley Basin Groundwater
Sustainability Plan (GSP), and associated hydrogeologic modeling and basin management efforts. These
efforts have improved the City’s understanding of groundwater conditions, sustainable yield, basin
management requirements, groundwater quality, and the role groundwater can play in the City’s long-term
water supply portfolio. Based on this additional information, groundwater is included in the 2025 UWMP as
a supplemental local supply source intended to improve supply diversification and resiliency.
The City has also advanced a groundwater cleanup project that is expected to restore the City’s ability to
physically extract and treat groundwater for potable use. The City completed a comprehensive
characterization of a tetrachloroethylene (PCE) plume th at underlies the most productive areas of the
groundwater basin and is implementing a groundwater cleanup program that includes installation of eight
new monitoring wells, two new extraction wells, and a treatment system utilizing granular activated carbon
for PCE removal. This project is supported by State grant funding and is expected to restore groundwater
as a supplemental potable water supply beginning in FY 2027-28. Once completed, the project is expected
to provide the City with wells and treatment facilities capable of producing and treating groundwater
consistent with the volumes identified through the GSP and related planning efforts. The City estimates that
the new groundwater wells could
increase available water supplies by
approximately 700 acre-feet per year.
Table 6-3: Groundwater Pumping
Volumes shows the City’s
groundwater production for 2021
through 2025. These production
amounts do not include agricultural or
private groundwater pumping by non-
City entities. As shown in Table 6-3:
Groundwater Pumping Volumes, the
City did not produce groundwater
during the current UWMP reporting
period.
Groundwater Sustainability Plan Adoption and Implementation
The San Luis Obispo Valley Groundwater Basin (Basin) is subject to SGMA regulations, which require high-
and medium-priority groundwater basins to be managed under a Groundwater Sustainability Plan. The City
of San Luis Obispo and the County of San Luis Obispo formed Groundwater Sustainability Agencies within
their respective jurisdictions to provide groundwater management coverage for the entirety of the Basin.
The San Luis Obispo Valley Basin GSP was recommended for adoption by the Groundwater Sustainability
Commission on October 20, 2021, adopted by both the City and County GSAs on December 7, 2021, and
submitted to DWR by the January 31, 2022 SGMA deadline. DWR approved the GSP on April 27, 2023 .
The GSP provides the framework for long-term sustainable management of the Basin and identifies
monitoring, reporting, and implementation actions intended to avoid undesirable results and achieve
groundwater sustainability. The City continues to participate in GSP implementation through coordination
with the County GSA and other basin stakeholders. Implementation activities include ongoing groundwater
level and water quality monitoring, preparation of annual reports, evaluation of basin conditions, and
coordination on management actions and projects identified in the GSP .
The City’s planned reinitiation of groundwater production is intended to be consistent with the GSP and the
long-term sustainable management of the Basin. Future groundwater use will be coordinated with GSP
implementation and will consider basin conditions, water quality, monitoring results, and applicable
management criteria established through the SGMA process. Groundwater is included in this UWMP as a
supplemental local supply because the City now has improved basin information from SGMA and G SP
TABLE 6-3: GROUNDWATER PUMPING VOLUMES
Basin Name 2021 2022 2023 2024 2025
San Luis Obispo
Valley (Basin 3-9) 0 0 0 0 0
Notes:
1. Water volumes are in acre-feet per year.
2. Department of Water Resources, Table 6-1.
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implementation and is advancing treatment and extraction infrastructure needed to restore groundwater
production for potable use. Restoration of City groundwater production would provide a supplemental local
supply that improves supply diversification and resiliency while remaining subject to GSP implementation
and applicable regulatory requirements. It is expected that City staff will propose a modification to the City’s
water supply accounting methodology as part of the next WWE update to include groundwater production
in future water supply availability calculations.
6.2.5 Recycled Water
The City produces recycled water at the WRRF located on Prado Road in the southern portion of the City.
Recycled water produced at the WRRF is utilized for non-potable beneficial uses and serves to offset
potable water demands within the community. The Cit y’s recycled water program is regulated pursuant to
Title 22, Division 4 of the California Code of Regulations and the City’s National Pollutant Discharge
Elimination System (NPDES) permit requirements administered by the RWQCB.
The City’s recycled water system was constructed as part of the City’s Water Reuse Project, which was
completed in 2006. The project included upgrades to the WRRF, construction of approximately eight miles
of recycled water distribution pipeline, recycled water storage facilities, and a recycled water pump station.
The recycled water distribution system was designed to
serve a single pressure zone and currently provides
recycled water primarily for landscape irrigation and
construction-related uses.
Recycled Water Coordination
The City owns and operates the wastewater collection
system, WRRF, recycled water treatment facilities,
storage and pumping facilities, and a dedicated
recycled water distribution system serving the City’s
recycled water customers. Because the City is both the wastewater collection/treatment agency and the
recycled water supplier within its service area, recycled water planning is coordinated internally among the
City’s wastewater treatment, water resources, and engineering sections. The City also coordinates recycled
water planning with applicable regulatory and planning agencies, including the Central Coast RWQCB and
DDW.
Wastewater Collection, Treatment, and Disposal
The City collects wastewater generated within its service area and conveys it to the WRRF for treatment.
The wastewater collection system serves residential, commercial, industrial, institutional, and governmental
customers within and adjacent to the City, including major institutional users such as Cal Poly and the
County Regional Airport. Wastewater is conveyed through the City’s collection system to the WRRF for
treatment, reuse, or discharge.
The WRRF provides tertiary treatment and disinfection prior to recycled water use or discharge. Following
recent facility upgrades completed in 2025, the WRRF has a treatment capacity of approximately 5.4 MGD
and is designed to produce high-quality tertiary treated effluent suitable for approved recycled water uses.
Treated effluent that is not used as recycled water is discharged to San Luis Obispo Creek in accordance
with the City’s applicable discharge permit requirements. The City is required to maintain minimum treated
effluent discharges of approximately 1.6 MGD to San Luis Obispo Creek to support downstream aquatic
habitat and fisheries resources. Because this environmental discharge requirement represents a n ongoing
operational commitment, not all treated effluent is available for recycled water use. The amount of recycled
water available for beneficial reuse therefore depends on wastewater influent flows, treatment plant
operations, required creek discharge volumes, recycled water storage and pumping capacity, and seasonal
customer demand. Table 6-4 documents the volume of wastewater received by the City in FY 2025, as well
as the volumes of recycled water sold to customers, discharged to the creek to meet environmental
regulations, and the remaining surplus volume after all commitments were met.
Recycled Water Supply
✓Non-Potable Water Supply
✓Over 1,000 acre-feet Available Annually
✓Reliable during 5-Year Drought
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Recycled water availability for planning purposes depends not only on the total volume of treated effluent
produced at the WRRF, but also on required San Luis Obispo Creek discharge, customer demand,
seasonal irrigation patterns, storage capacity, pumping capacity, and recycled water distribution
infrastructure. These factors are evaluated through the City’s Recycled Water Delivery Model, which is
discussed further in Section 6.3.5.
Current Recycled Water Use
The City currently delivers recycled water to parks, schools, roadway medians, common landscape areas,
Laguna Lake Golf Course, Caltrans landscape irrigation systems, construction water users, and other
authorized non-potable uses. Recycled water is distributed through a metered system and is primarily used
for landscape irrigation during the dry summer months. The City also maintains a construction water permit
program that allows contractors to use recycled water for dust control and soil compaction activ ities within
the community.
Recycled water use varies seasonally. Demands are highest during the summer irrigation season and
decline substantially during wetter winter months. As a result, there are periods when treated effluent
available after required creek discharge exceeds current beneficial reuse demand.
Projected and Potential Recycled Water Use
Projected recycled water use is based on existing metered recycled water use, anticipated development
within the recycled water service area, the City’s mandatory recycled water use ordinance, and planning
assumptions from the City’s 2017 Recycled Water Ma ster Plan. Future recycled water use is expected to
remain primarily irrigation-driven, with stable use associated with construction water and other authorized
non-potable uses where recycled water service is feasible.
The City’s recycled water projections assume continued growth in beneficial recycled water use over time
as additional customers connect to the recycled water system or increase use where service is available.
For planning purposes, the City assumes recycled water demand will increase by approximately 10 acre -
feet per year over the UWMP planning horizon. These projected uses are reflected in the normal-year non-
potable supply volumes presented in Section 6.4.3.
TABLE 6-4: TREATED WASTEWATER USES WITHIN CITY IN FY 2025 (IN ACRE-FEET)
Total Wastewater
Treated Required Creek Releases Recycled Water Demand Surplus Recycled Water
4,488 1,792 288 2,408
TABLE 6-5: FY 2025 RECYCLED WATER DEMAND BY CUSTOMER CLASS
Customer Class FY 2025 FY 2030 FY 2035 FY 2040 FY 2045 FY 2050
Landscape
Irrigation (excluding
golf course)
243 293 343 393 443 493
Golf Course
Irrigation 33 33 33 33 33 33
Construction Water 12 12 12 12 12 12
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In addition to forecasting and planning for the expanded use of non-potable recycled, the City has also
identified potential future recycled water opportunities that could increase beneficial reuse beyond currently
projected demands. These opportunities may include service to additional development areas, retrofit of
existing potable irrigation accounts, increased construction water use, expanded non -potable distribution
infrastructure, indirect potable reuse, direct potable reuse, or other beneficial reuse applications. These
potential uses would require additional technical analysis, infrastructure planning, regulatory review,
environmental evaluation, cost analysis, public engagement, and future City Council direction before being
implemented or relied upon as future water supplies.
Actions to Encourage and Optimize Future Recycled Water Use
The City will continue to evaluate opportunities to optimize and expand recycled water use where feasible.
The City has adopted a mandatory recycled water use ordinance codified in Municipal Code Chapter 13.24,
which authorizes the City to require recycled water use in lieu of potable water where recycled water service
is determined to be feasible. This ordinance supports continued expansion of irrigation -driven recycled
water use as development occurs within or near the recycled water service area.
The City’s 2017 Recycled Water Master Plan identified future recycled water expansion opportunities,
including service to planned development areas, retrofit of existing irrigation systems, hydraulic
improvements, storage considerations, and potential future beneficial reuse applications. The City will
continue to evaluate these opportunities based on infrastructure feasibility, seasonal demand, available
treated effluent after required creek discharge, customer readiness, cost, regulatory requirements, and
consistency with City planning objectives.
6.3 Water Supply Modeling and Yield Assessment
6.3.1 Overview of Water Supply Planning Methodology
Long-Term Water Supply Planning
The City uses related but different methods to evaluate long-term water supply reliability and near-term
operational reliability within the 2025 UWMP. These methods serve different purposes and rely on different
types of information.
For long-term water supply planning, the City relies on the policy framework established in the General Plan
and WWE. The WWE includes both a water resource availability calculation and a water supply accounting
framework. The water resource availability calculation identifies the City’s recognized water supply sources
and long-term planning adjustments. The WWE identifies the available yield from each water resource
based on the nature of that source, including safe annual yield for Salinas and Whale Rock Reservoirs,
contractual supply from Nacimiento Reservoir, prior-year recycled water use, and a long-term deduction for
expected reservoir siltation.
The WWE water supply accounting framework then evaluates the City’s available water resources in
relation to three community needs: primary water supply, reliability reserve, and secondary water supply.
Primary water supply represents the amount of water n eeded to serve the General Plan buildout population.
Reliability reserve provides a buffer for future unforeseen or unpredictable long-term impacts to the City’s
available water resources. Secondary water supply represents remaining water resources after a ccounting
for primary water supply and reliability reserve and is intended to help address peak demand periods or
short-term loss of City water supply sources.
For purposes of the 2025 UWMP, the City applies the WWE framework using the best available current
supply information and the planning horizon required for the UWMP. Long -term water resource availability
includes the City’s contractual supply from Nacimiento Reservoir, the combined safe annual yield of Salinas
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and Whale Rock Reservoirs, recycled water use as a non-potable supply, and a reduction in available
supply to account for future siltation in Salinas and Whale Rock reservoirs. The 2025 UWMP also evaluates
planned groundwater production as a future supplemental potable supply when available. Because
groundwater was not included as an available supply in prior UWMP accounting, this UWMP identifies
groundwater as a potential source of supply and explains the basis for including it in future reliability
analysis.
For UWMP presentation and reliability analysis, potable and non -potable supplies are shown separately
where appropriate. Salinas Reservoir, Whale Rock Reservoir, Nacimiento Reservoir, and planned
groundwater production are evaluated as potable supplies. Re cycled water is evaluated as a non-potable
supply that offsets potable demand where recycled water service is available, feasible, and authorized. This
presentation helps distinguish between supplies available to meet potable demands and recycled water
supplies available for approved non-potable uses, while remaining consistent with the WWE’s broader
water resource availability and supply accounting framework.
Near-Term Water Supply Planning
The City conducts near-term operational reliability analysis for upcoming single-year assessments, the five-
year drought risk assessment, and WSCP implementation using a different methodology because these
analyses serve a different purpose than long-term water supply planning. Rather than evaluating long-term
supply sufficiency for General Plan consistency, near-term analyses evaluate whether the City can meet
expected demands during a specific upcoming period and whether shortage response actions may be
needed.
For near-term operational reliability analysis, the City uses its Water Projection Model informed by current
or projected near-term conditions. Model inputs may include actual reservoir storage, groundwater
availability, recycled water availability, recent community water use, current population estimates, seasonal
demand patterns, known or anticipated infrastructure constraints, and dry -year hydrologic assumptions.
This approach is more appropriate for near-term evaluations because the City has better information about
actual operating conditions and expected customer demand over a one - to five-year period than would be
reflected by applying long-term buildout demand assumptions and long-term supply planning values that
were developed in order to plan for future community growth.
The City’s Water Projection Model is separate from, but complementary to, the City’s long -term supply
planning tools. The safe annual yield model for Salinas and Whale Rock Reservoirs estimates the long -
term reliable annual supply from the coordinated operation of the two reservoirs under historical and
modeled hydrologic conditions. The Water Projection Model is used as an operational and planning tool to
evaluate how current storage, projected demands, Nacimiento deliveries, groundwater availability, recy cled
water use, infrastructure constraints, and hydrologic assumptions may affect the City’s ability to meet
demands over a defined near-term period.
Using different methods for long-term planning and near-term operational analysis helps ensure that each
analysis is appropriately matched to its purpose. Applying current demands alone to long -term planning
could understate future needs and would not provide the conservative basis needed for General Plan
consistency and multi-decade water supply planning. Conversely, applying long-term buildout population
assumptions and the 117 gpcd planning value to near -term operational analyses could overstate expected
customer demand and misrepresent actual shortage risk during upcoming assessment periods.
6.3.2 Salinas and Whale Rock Safe Annual Yield Modeling and Reliability
The City utilizes a computer-based hydrologic and operational model to evaluate the coordinated operation
of Salinas Reservoir and Whale Rock Reservoir and to estimate the combined safe annual yield of the two
reservoirs. Safe annual yield represents the quantity of water that can be reliably withdrawn jointly from the
two reservoirs on a long-term basis while maintaining acceptable levels of reliability under varying
hydrologic conditions.
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Salinas Reservoir and Whale Rock Reservoir are operated
conjunctively because the two reservoirs have different
physical, hydrologic, and climatic characteristics. Salinas
Reservoir has a larger watershed and smaller storage
capacity than Whale Rock Reservoir, allowing it to respond
more quickly to runoff events and recover storage more
readily under favorable hydrologic conditions. However,
Salinas Reservoir is located farther inland, where warmer
temperatures and higher evaporation rates can cause stored
water to decline more quickly than at Whale Rock Reservoir.
On the converse, Whale Rock Reservoir has a smaller
watershed but approximately double the storage capacity.
Because of this, Whale Rock Reservoir generally requires more sustained rainfall and runoff to refill, but
once water is stored, the reservoir experiences lower evaporation rates due to its cooler coastal location.
These differences make the two reservoirs complementary. Salinas Reservoir provides operational
flexibility and the ability to recover storage more quickly during favorable hydrologic conditions, while Whale
Rock Reservoir provides larger carryover storage and lower evaporative losses to help sustain supplies
during extended dry periods.
The City’s joint operation of Salinas and Whale Rock Reservoirs is intended to maximize the reliability of
the combined reservoir system. Operational decisions consider reservoir storage levels, runoff conditions,
evaporation, seasonal demands, downstream release requirements, water quality, treatment and
conveyance limitations, and the long-term need to preserve supply reliability. In general, the City may
prioritize use of Salinas Reservoir when water is available, while Whale Rock Reservoir provides
supplemental supply and longer-term carryover storage benefits as part of the combined reservoir system.
The coordinated operation of Salinas and Whale Rock Reservoirs is evaluated through the City’s Safe
Annual Yield (SAY) model. The model simulates the combined operation of the two reservoirs under
historical hydrologic conditions and estimates the quantity of water that can be reliably withdrawn while
maintaining acceptable levels of reliability. Because the model reflects the conjunctive operation of the two
reservoirs, the resulting safe annual yield represents the combined reliable yield of the Salinas and Whale
Rock reservoir system rather than the independent yield of either reservoir.
The City’s SAY model was first developed in 1988. At that time, the 1946–1951 drought was the controlling
drought period. The model was updated in 1991 to incorporate the 1986 –1991 drought, which became the
new controlling condition for estimating safe annual yield. Based on that update, the City estimated the
combined SAY from Salinas and Whale Rock Reservoirs to be 6,940 acre-feet per year. This value was
used in prior City planning documents, including UWMPs prior to the 2020 UWMP and updates to the
General Plan WWE. Following the extended 2006–2016 drought period, the City initiated an update to the
SAY model. The update was intended to verify historical hydrologic input data, document and validate
model calculations, incorporate the full extent of the 2006–2016 drought period, and evaluate potential
climate change effects. The updated model incorporated verified historical data for reservoir inflows,
precipitation, evaporation, and downstream releases. The updated analysis resulted in a revised combined
SAY estimate of 4,910 acre-feet per year for Salinas and Whale Rock Reservoirs. This represented a
reduction of approximately 2,000 acre-feet per year from the previously used estimate of 6,940 acre-feet
per year. Two primary factors contributed to this reduc tion. First, updated historical evaporation data
showed evaporation losses approximately 30 percent higher than the prior model. Second, the updated
model incorporated the full 2006–2016 drought period, which was more severe than the 1986–1991 drought
and became the new controlling drought period for estimating SAY.
To provide flexibility, the updated model evaluated potential climate change scenarios using projections
from EPA’s Climate Resilience Evaluation and Awareness Tool, SLOCOG’s 2014 Regional Transportation
Plan, the Nature Communications Journal, and other published climate information. These scenarios
produced a range of potential future SAY values. EPA climate change scenarios resulted in modeled safe
annual yield values ranging from approximately 4,690 to 5,050 acre-feet per year, SLOCOG scenarios
Conjunctive use refers to the
coordinated operation of multiple water
supplies to improve overall system
reliability. The City operates Salinas and
Whale Rock reservoirs together by
balancing reservoir use based on
available storage, hydrologic conditions,
operational constraints, treatment needs,
and long-term supply reliability.
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ranged from approximately 4,050 to 5,070 acre-feet per year, and the Nature Communications Journal7
climate change scenario resulted in a modeled value of approximately 4,950 acre -feet per year.
Because of uncertainty regarding future precipitation, runoff, and evaporation patterns on the Central Coast,
the City uses the updated 4,910 acre-foot per year safe annual yield estimate as a conservative planning
value for Salinas and Whale Rock Reservoirs. The SAY model is intended to remain a planning and
operational tool that can be updated as additional hydrologic data become available. Continued
coordination between the City, Cal Poly, and other Whale Rock Reservoir stakeholders is important to
maintaining an accurate understanding of expected reservoir supply availability.
Updated Bathymetric Information and Safe Annual Yield Planning Assumptions
In 2024, the City received updated bathymetric information for Salinas Reservoir. The updated information
estimated the long-term reservoir storage loss due to siltation at approximately 46.27 acre-feet per year.
This value is generally consistent with the siltation assumptions used in prior water supply planning and
safe annual yield modeling efforts.
The City’s current combined SAY estimate for Salinas and Whale Rock Reservoirs is 4,910 acre-feet per
year, as described above. This value was developed through the City’s updated SAY model, which
incorporated verified historical hydrologic data, updated evaporation information, reservoir operations,
downstream release requirements, and the extended 2006 –2016 drought period. The 4,910 acre-foot per
year value remains the City’s current planning basis for the combined Salinas and Whale Rock Reservoir
supplies.
The updated 2024 bathymetric information does not result in an immediate change to the safe annual yield
value used in this UWMP. The City’s long-term water supply planning already includes a conservative 500
acre-foot per year reduction to account for future reservoir siltation. The updated Salinas Reservoir siltation
estimate of 46.27 acre-feet per year remains within the planning buffer provided by this reduction and does
not indicate a material change requiring immediate recalculation of the safe annual yield model.
The City will incorporate the 2024 Salinas Reservoir bathymetric information into the next comprehensive
updates of the WWE and SAY model. Future updates to the model may also incorporate additional
hydrologic data, updated evaporation information, reservoir storage information, climate-related
assumptions, operational considerations, and any updated bathymetric information for Whale Rock
Reservoir. This approach allows the City to maintain conservative and reliable water supply planning
assumptions while avoiding piecemeal annual revisions to the SAY estimate based on individual data
updates.
6.3.3 Nacimiento Water Supply Reliability
In 2002, the San Luis Obispo County Flood Control and Water Conservation District (District) retained the
services of Boyle Engineering Corporation to assess the ability of the Nacimiento Reservoir to reliably
provide the District’s entitlement of 17,500 AFY to the District contractors. As part of the analysis, the study
took into account the agreement with the Monterey County Water Resources Agency (MCWRA), which
owns and operates the Nacimiento Reservoir facilities, that stipulates that the District entit lement through
operational procedures will be “preserved” in the reservoir due to MCWRA being contractually obligated to
maintain a “minimum pool” for the benefit of the District. This enables the District to maintain deliveries to
the participating agencies even when reservoir levels are low, meaning that unless the water storage
capacity drops below the “dead pool” of the reservoir, the District’s entitlement will always be availa ble. The
2002 study took into account the following factors:
• Short-term power outages
• Delivery facility failure
7 Technical Memorandum, Salinas and Whale Rock Reservoirs Safe Annual Yield (Water Systems Consulting, January
2018)
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• Energy costs
• Drought
• Contamination of supply
• Environmental restrictions
Upon completion of the analysis, the 2002 study summarized that even though there have been several
periods of drought, both short-term and long-term, the total annual entitlement for the District could be
delivered consistently, even in periods of extended drought.
During the worst-case drought on record in the region (201 2 to 2015), Nacimiento Reservoir remained a
resilient water supply capable of providing a consistent and reliable source of water for San Luis Obispo
County, which includes the City’s contractual amount of 5,482 acre -feet per year. To confirm the prior
analysis with more recent data, the City reviewed rainfall and inflow data from 2013 which was the driest
year on record. Over that year, Nacimiento Reservoir received 35,000 acre-feet of inflow. Though this is
significantly below the average inflow into the reservoir, the District’s entitlement could still be met if inflow
remained at this level.
Based on the 2002 reliability analysis, the contractual minimum pool requirements, and more recent
drought-period inflow data, Nacimiento Reservoir is considered a reliable component of the City’s potable
water supply portfolio for purposes of the 2025 UWMP and associated drought planning.
In the short-term, recent damage to the Nacimiento
pipeline has resulted in reductions to available supplies
that should be considered when planning near-term
deliveries. In January 2023, atmospheric river storm
events caused significant flooding within the Salinas
River and damaged portions of the Nacimiento raw
water transmission pipeline. Following the storm
damage, deliveries of Nacimiento water to the City
were interrupted. A temporary pipeline was
subsequently installed in July 2025 to restore partial
deliveries of Nacimiento water to the City. The
temporary pipeline is capable of delivering
approximately 3.2 MGD to the City’s WTP; however,
operation of the temporary facility is prohibited during
periods when streamflow is present within the Salinas
River. The City continues to coordinate with
participating agencies regarding long-term repair and
restoration of the Nacimiento transmission system and
the pipeline, which is expected to be restored to full
capacity in FY 2027-28.
6.3.4 Groundwater Supply Reliability / Planned
Groundwater Supply
Groundwater is not currently relied upon to meet the
City’s existing potable water demands; however, the
City is implementing projects intended to restore
groundwater production as a supplemental potable
water supply. As described in Section 6.2.4, groundwater was not included as a long-term available supply
in prior planning documents because it was not an active potable source and had water quality and reliability
limitations. For the 2025 UWMP, planned groundwater production is included as a future supplemental
supply because the City has improved its understanding of the capacity and functionality of the groundwater
basin through development of the GSP. Accordingly, the City is currently constructing new groundwater
monitoring, extraction, and treatment infrastructure needed to restore potable groundwater use.
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The planned groundwater supply is expected to improve operational flexibility, diversify the City’s water
supply portfolio, and provide additional resiliency under drought or infrastructure -constrained conditions.
With this, groundwater would be operated as part of the City’s integrated water supply portfolio rather than
as an independent supply source. The City’s primary potable supplies would remain its three surface water
reservoirs, with groundwater production used to supplement these supplies, support reservoir storage
management, reduce reliance on surface water during certain conditions, and provide redundancy during
drought or infrastructure-related constraints.
Future City groundwater production will be coordinated with implementation of the San Luis Obispo Valley
GSP and will consider groundwater levels, water quality, basin management criteria, treatment capacity,
water level and water quality monitoring results, and other applicable regulatory requirements. The timing
and quantity of groundwater production would also be coordinated with Salinas and Whale Rock Reservoir
storage conditions, Nacimiento delivery availability, overall system demands, and the City’s long -term
supply reliability objectives.
For purposes of this UWMP, groundwater is assumed to become available beginning in FY 2027 –28 and
is projected to provide up to 700 acre-feet per year under normal planning conditions. This supply is
incorporated into the City’s projected water supply portfolio beginning with the 2030 planning increment,
the first five-year UWMP planning increment following anticipated implementation.
Consistent with the sustainable management criteria outlined in the Groundwater Sustainability Plan, the
City may apply source-specific dry-year adjustments to assumed groundwater availability to avoid or
minimize potential impacts to surface water flows and basin conditions. As a result, groundwater availability
may be lower during dry-year or multiple dry-year planning scenarios than under normal planning
conditions. These assumptions are reflected in the water service reliability analyses presented in Ch apter
7.
As the City completes groundwater treatment and extraction facilities and begins operating the restored
groundwater supply, staff anticipate recommending that future updates to the General Plan WWE and water
supply accounting methodology be revised to include groundwater production in future water supply
availability calculations, as appropriate.
6.3.5 Recycled Water Supply Reliability
Recycled water is an important non-potable supply that offsets potable water demand where recycled water
service is available. The City produces recycled water at the Water Resource Recovery Facility (WRRF),
where treated effluent is available for approved non-potable uses after accounting for required discharge
to San Luis Obispo Creek and applicable regulatory requirements. Recycled water is evaluated separately
from potable water because it is not available to meet drinking water demands and is limited b y customer
demand, seasonal irrigation patterns, storage capacity, pumping capacity, distribution infrastructure, WRRF
operations, and regulatory discharge obligations.
The City uses a Recycled Water Delivery Model to evaluate non-potable recycled water availability under
current and projected system conditions. The model considers expected wastewater influent flows, recycled
water production, storage tank capacity, pump station capacity, customer demand volumes, seasonal
demand patterns, and required discharge to San Luis Obispo Creek. The model is used to estimate the
amount of recycled water that can reasonably be made available for approved non -potable uses, rather
than simply reporting the total theoretical volume of treated effluent produced at the WRRF. This distinction
is important because recycled water reliability depends not only on the amount of treated effluent produced,
but also on the City’s ability to store, pump, distribute, and beneficially use recycled water when demand
occurs.
Based on recent modeling, recycled water availability is not limited by the total volume of treated wastewater
effluent available for reuse. Instead, the primary near-term limiting factor is the City’s current recycled water
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pumping capacity at the WRRF. Accordingly, the City distinguishes between total recycled water produced
and the amount of recycled water that can reasonably be stored, pumped, and delivered with existing
infrastructure. This distinction is important when evaluating recycled water availability for near-term
assessments and future planning.
For long-term UWMP planning, recycled water supply reliability is evaluated based on current recycled
water use, anticipated growth in recycled water demand, potential future customer connections, system
capacity, regulatory discharge requirements, and opportunities to expand beneficial reuse over time. The
City’s recycled water planning assumptions reflect continued growth in recycled water use, including an
estimated increase in customer demand of approximately 10 acre -feet per year as additional customers
connect to the recycled water system and existing uses expand where feasible.
The City currently produces recycled water in excess of existing customer demand, including during dry
periods when irrigation demand is higher. This provides a reliable non-potable resource for existing recycled
water customers and supports future opportunities to offset potable demand. However, the amount of
recycled water that can be used beneficially is constrained by the timing and location of demand, delivery
infrastructure, pump station capacity, storage capacity, and required San Luis Obispo Creek d ischarge.
Future increases in recycled water use will depend on the City’s ability to match available recycled water
supply with customers that can use recycled water when and where it is available. This may require
additional customer connections, distribution syst em improvements, pumping or storage capacity,
operational changes, or regulatory coordination.
The City will continue to evaluate recycled water system expansion, optimization of existing recycled water
deliveries, and future opportunities for increased beneficial use. These efforts may include additional non -
potable reuse, expanded customer connect ions, delivery system improvements, and continued evaluation
of potable reuse opportunities. Potable reuse is being studied and considered as a potential future water
supply strategy, but it is not relied upon as an existing or projected potable supply in this UWMP.
6.4 Current Year Water Use and Normal-Year Supply Availability
6.4.1 Current Year Water Supply and Demand
The City reports actual water supply volumes on a fiscal-year basis for purposes of this UWMP. In this plan,
the current year is reported as FY 2025, which represents the period from July 1, 2024 , through June 30,
2025. Accordingly, references to current-year actual water supply use in this section mean actual water
supply volumes used during FY 2024–25.
Actual water supply volumes used during FY 2025 differ from the City’s normal -year supply availability
because Nacimiento Reservoir deliveries were unavailable due to damage to the Nacimiento transmission
pipeline caused by 2023 storms. As a result, the City’s current-year water use by source does not reflect
the City’s expected normal-year supply portfolio when the Nacimiento transmission system is available.
The absence of Nacimiento deliveries in FY 2025 reflects a temporary conveyance limitation rather than a
permanent change in the City’s Nacimiento Reservoir entitlement or long -term supply planning
assumptions. Table 6-6 summarizes actual FY 2025 source use and does not represent the City’s normal-
year supply availability. Projected normal-year potable and non-potable supply volumes are presented in
Sections 6.4.2 and 6.4.3.
TABLE 6-6: FY 2025 ACTUAL WATER SUPPLY USE BY SOURCE
Water Supply Source Potable or Non-Potable FY 2025 Volume Used (acre-feet)
Salinas Reservoir Potable 2,385
Whale Rock Reservoir Potable 2,448
Nacimiento Reservoir Potable 0
Non-Potable Recycled Water Non-Potable 288
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Subtotal for Potable 4,833
Subtotal for Non-Potable 288
Total Use (Potable and Non-Potable) 5,121
Notes:
1. Nacimiento Reservoir was not utilized in FY 2025, as it was offline due to pipeline damage from 2023
storms.
2. Groundwater was not utilized as a water supply in FY 2025.
3. Values are rounded to nearest whole number.
6.4.2 Projected Normal-Year Potable Water Supply Volumes
Under normal operating conditions, the City’s potable water supply portfolio includes surface water from
Salinas Reservoir, Whale Rock Reservoir, and Nacimiento Reservoir, with planned groundwater production
expected to become available beginning in FY 2027-28. Projected normal-year potable water supply
volumes are shown in Table 6-7 and represent the City’s estimated potable supply availability over the
UWMP planning horizon based on existing water rights, ownership interests, contractual entitlements,
infrastructure capacity, treatment capacity, planned projects, and adopted water s upply planning
assumptions.
Salinas and Whale Rock Reservoirs are shown as a combined potable supply because the City evaluates
these reservoirs through a combined safe annual yield analysis. As described in Section 6.3.2, the City’s
safe annual yield model evaluates the coordinated operation of the two reservoirs using historical hydrology,
reservoir inflows, precipitation, evaporation, downstream releases, withdrawals, and minimum pool
constraints. The updated model, which incorporated the extended 2006–2016 drought period, resulted in a
revised combined safe annual yield of 4,910 acre-feet per year. For long-term planning purposes, the City
applies a 500 acre-foot per year adjustment to account for future reservoir siltation. Accordingly, the
projected normal-year potable supply volume shown in Table 6-7 for Salinas and Whale Rock Reservoirs
is 4,410 acre-feet per year.
Nacimiento Reservoir is shown at 5,482 acre-feet per year, reflecting the City’s contractual entitlement. The
projected normal-year volumes assume restoration of Nacimiento conveyance capacity following
completion of permanent pipeline repairs, currently estimated to occur in FY 2027-28.
Groundwater is shown as a planned future potable supply beginning with the 2030 planning increment.
Although groundwater was not used during FY 2025 and was not included as an available supply in the
2020 UWMP, the City is implementing projects intended to restore groundwater production as a
supplemental potable supply beginning in FY 2027 –28. For UWMP planning purposes, groundwater is
incorporated into projected normal-year supply availability beginning in 2030, the first five-year planning
increment after expected implementation.
TABLE 6-7: PROJECTED NORMAL-YEAR POTABLE WATER SUPPLY VOLUMES (IN ACRE-FEET)
Water Supply Source 2030 2035 2040 2045 2050
Salinas and Whale Rock Reservoirs 4,410 4,410 4,410 4,410 4,410
Nacimiento Reservoir 5,482 5,482 5,482 5,482 5,482
Groundwater 700 700 700 700 700
Total Potable Water Supply Availability 10,592 10,592 10,592 10,592 10,592
Notes:
1. Salinas and Whale Rock Reservoirs are shown combined because the City evaluates these reservoirs
through a combined safe annual yield analysis.
2. Nacimiento Reservoir projections assume restoration of conveyance capacity following completion of
permanent pipeline repairs, which are currently estimated to occur in 2027.
3. Groundwater production is planned to begin during FY 2027-28
4. Groundwater was not utilized as a water supply in FY 2025 or in the 2020 UWMP.
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6.4.3 Projected Normal-Year Non-Potable Water Supply Volumes
The City’s non-potable water supply consists of recycled water produced at the WRRF and delivered for
approved non-potable uses. Recycled water is evaluated separately from potable water because it is not
available to meet drinking water demands and is served through separate recycled water infrastructure.
Recycled water use offsets potable water demand where recycled water service is available, but the amount
of recycled water that can be beneficially used depends on customer demand, seasonal irrigation pa tterns,
distribution system capacity, pumping capacity, storage capacity, WRRF operations, and regulatory
discharge requirements.
For UWMP planning purposes, projected normal-year non-potable supply volumes represent the amount
of recycled water expected to be available for approved beneficial use during the planning horizon. These
projections consider existing recycled water use, anticipated growth in recycled water demand, potential
future customer connections, system capacity, and the City’s ongoing efforts to optimize recycled water
use within City limits.
The City uses a Recycled Water Delivery Model to evaluate recycled water availability under current and
projected system conditions. The model considers wastewater influent flows, recycled water production,
storage tank capacity, pump station capacity, customer demand volumes, seasonal demand patterns, and
required discharge to San Luis Obispo Creek. The model helps distinguish between the total volume of
treated effluent produced at the WRRF and the amount of recycled water that can reasonably be stored,
pumped, delivered, and used due to known infrastructure limitations.
Recent recycled water modeling indicates that recycled water availability is not limited by the total volume
of treated effluent produced at the WRRF. Instead, the primary near-term limiting factor is the City’s current
recycled water pumping capacity at t he WRRF. For this reason, near-term recycled water availability
estimates are based on the amount of recycled water that can reasonably be stored, pumped, and delivered
with existing infrastructure, rather than the larger volume of treated effluent that ma y be produced at the
WRRF.
For long-term UWMP planning, the City assumes continued growth in recycled water use over time. The
City’s recycled water planning assumptions include an estimated increase in customer demand of
approximately 10 acre-feet per year as additional customers connect to the recycled water system and
existing uses expand where feasible. Future increases in recycled water use will depend on the City’s ability
to match available recycled water supply with customers that can use recycled water when and where it is
available. This may require additional customer connections, distribution system improvements, pumping
or storage capacity, operational changes, or regulatory coordination. Table 6-8 summarizes the City’s
projected normal-year non-potable recycled water supply volumes through the UWMP planning horizon.
TABLE 6-8: PROJECTED NORMAL-YEAR NON-POTABLE WATER SUPPLY VOLUMES (IN ACRE-FEET)
Non-Potable Water Supply Source 2030 2035 2040 2045 2050
Recycled Water from City WRRF 1,296 1,296 1,296 1,296 1,296
6.4.4 Energy Use Information
California Water Code section 10631.2 requires urban water suppliers to include energy-related information
that can be readily obtained. The City’s water system uses energy to convey, treat, store, and distribute
potable and non-potable water. Energy use generally varies from year to year based on water demand,
source selection, reservoir levels, treatment requirements, demand patterns, actual water use, and other
operational conditions.
The City relies on multiple water supply sources, including Salinas Reservoir, Whale Rock Reservoir,
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Nacimiento Reservoir, and recycled water. Estimating source-specific raw water conveyance energy can
be difficult because several of the City’s water sources involve shared facilities, regional conveyance
systems, or jointly managed infrastructure that also serve or benefit other w ater purveyors. As a result, raw
water conveyance energy is not readily obtainable and is therefore not provided.
For this UWMP, the City provides readily available energy information associated with City -operated
potable water treatment and distribution facilities . The City’s Water Treatment Plant uses energy for
treatment processes, chemical feed systems, ozone generation, pumping, plant service water, monitoring
and control systems, and other facility operations. After treatment, additional energy is required to mo ve
water through portions of the City’s distribution system, including pump stations, pressure zones, s torage
facilities, and related control systems.
Energy use is closely related to water demand and system operations. Higher water demands generally
increase the amount of water that must be treated, pumped, stored, and delivered. However, annual energy
use may also vary depending on the mix of supplies used, the elevation and location of demands served,
reservoir operating conditions, water quality, recycled water production, groundwater availability, and
infrastructure constraints.
The City considers energy use as one factor in water system operations, infrastructure planning, capital
project development, and long-term resiliency planning. However, energy use is not evaluated
independently from water supply reliability, public health , treatment requirements, regulatory compliance,
infrastructure condition, emergency preparedness, cost, and operational flexibility. Detailed source -specific
energy intensity calculations are voluntary under DWR’s methodology and are not currently used as a
primary water supply planning metric by the City. The City will continue to evaluate readily available energy
information through water system operations, capital planning, and future UWMP updates. Table 6-9: FY
2025 Potable Water-Related Electricity Use documents readily available City-operated potable water
treatment and distribution electricity use during FY 2025.
TABLE 6-9: FY 2025 POTABLE WATER-RELATED ELECTRICITY USE
Water Treatment/Delivery
Function
Energy Demand
(kWh)
Water Produced/Delivered
(acre-feet) kWh/acre-foot
Water Treatment 1,804,616 4,832 373.47
Water Distribution 103,670 4,832 21.45
Total 1,908,286 4,832 394.93
Notes: Source water pumping data was not readily available at the time this report was prepared and is not
included in this table.
6.5 Planned Water Supply Projects and Programs
The City continues to implement and evaluate projects and programs intended to maintain and improve
water supply reliability, operational flexibility, and long-term resiliency. These efforts include restoration of
full Nacimiento Reservoir conveyance capacity, restoration of groundwater production, continued recycled
water system expansion, consideration of potable reuse, and studies related to regional desalination
feasibility.
Nacimiento Transmission System Restoration
The City is coordinating with Nacimiento Project participating agencies regarding long-term repair and
restoration of the Nacimiento transmission pipeline. Full restoration of the Nacimiento pipeline is expected
in FY 2027-28. Once full conveyance capacity is restored, the City expects Nacimiento Reservoir to
continue serving as a reliable component of the City’s potable water supply portfolio .
Planned Groundwater Production
As noted above, the City is implementing projects intended to restore groundwater as a supplemental
potable water supply. These efforts include groundwater cleanup, installation of new monitoring and
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extraction wells, treatment facilities, and related operational and regulatory coordination. Groundwater is
projected to become available in FY 2027-28 and is therefore included with the 2030 planning increment.
The projected groundwater supply volume is anticipated to be 700 acre-feet per year in normal-year
conditions, with reduced volumes available during dry-year conditions.
Recycled Water System Expansion
The City will continue to evaluate opportunities to optimize and expand recycled water use where feasible.
The City’s 2017 Recycled Water Master Plan identified future recycled water expansion opportunities and
included demand forecasts that assume continued growth in customer use of recycled water over time. For
planning purposes, those forecasts assume that recycled water demand will increase by approximately 10
acre-feet per year as additional customers connect to the recycled water system.
Potable Reuse
The City continues to evaluate potable reuse as a potential long-term water supply resiliency strategy.
Potable reuse could include indirect potable reuse, such as groundwater recharge or surface water
augmentation, or direct potable reuse, subject to appl icable State regulations, technical feasibility, public
health requirements, environmental review, infrastructure needs, cost, public engagement, and future City
Council direction. Potable reuse is being studied as a potential future supply opportunity and is not included
in the projected water supply volumes or reliability calculations presented in this UWMP.
Desalination
The City is monitoring and participating in regional discussions related to seawater desalination feasibility.
The San Luis Obispo County Flood Control and Water Conservation District is leading a regional
desalination feasibility planning effort to evaluate potential project alternatives, costs, constraints, and
implementation considerations. While desalination could potentially provide a drought -resilient regional
water supply in the future, it remains under study and is not included in the City’s project ed water supply
availability or reliability calculations in this UWMP.
6.6 Climate Change and Water Supply Considerations
Climate variability and climate-related uncertainty are important considerations in long-term water supply
planning. Potential climate-related effects relevant to the City’s water supply portfolio include changes in
precipitation patterns, increased frequency or severity of drought, changes in watershed runoff timing and
volume, increased evaporation, increased wildfire risk, degradation of raw water quality, and increased
stress on water infrastructure during extreme weather events.
Because the City relies primarily on surface water supplies from multiple watersheds, changes in rainfall,
runoff, reservoir inflows, evaporation, and watershed conditions may affect long-term supply availability.
The City’s revised safe annual yield analysis for Salinas and Whale Rock Reservoirs incorporates updated
historical hydrologic information, including the extended 2006–2016 drought period, and provides a
conservative basis for long-term supply planning. In addition, the City evaluated climate-related uncertainty
through separate climate sensitivity scenarios as part of the safe annual yield model update , allowing for
model runs to be conducted for a variety of climate scenarios .
The City’s safe annual yield model update evaluated potential climate change effects on Salinas and Whale
Rock Reservoirs using multiple climate projection sources, including EPA’s Climate Resilience Evaluation
and Awareness Tool, SLOCOG climate projections, and other published climate information. The climate
scenarios evaluated changes in precipitation, reservoir inflow, and evaporation. The resulting modeled safe
annual yield values ranged from approximately 4,050 acre -feet per year to 5,070 acre-feet per year,
depending on the climate scenario. These results demonstrate that future reservoir yield is sensitive to
changes in precipitation, runoff, and evaporation. They also support the City’s continued use of conservative
planning assumptions, including t he updated 4,910 acre-foot per year safe annual yield value, a separate
500 acre-foot planning adjustment for future reservoir siltation, and continued efforts to diversify the City’s
water supply portfolio.
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Climate-related uncertainty may also affect water quality, treatment operations, and infrastructure reliability.
Intense storm events can increase turbidity, organic matter, debris, and other water quality challenges in
surface water supplies. Extended dry periods may reduce reservoir inflows and degrade water quality within
each reservoir, most notably Salinas Reservoir due to its smaller storage volume and warmer inland
climate. Wildfire, watershed disturbance, and post-fire runoff may also affect reservoir water quality and
cause unanticipated reservoir capacity loss due to sedimentation.
These considerations reinforce the importance of maintaining a diversified supply portfolio, investing in
resilient water infrastructure, periodically updating hydrologic and operational models, and continuing
planning and feasibility efforts aimed at expa nding and diversifying the City’s water supply portfolio with
more drought-resilient supplies, such as potable reuse and/or participation in a regional desalination project,
subject to the discretion of the San Luis Obispo City Council.
6.7 Transfers and Exchanges
California Water Code section 10631(c) requires urban water suppliers to describe opportunities for
exchanges or transfers of water on a short-term or long-term basis. The City’s projected supply availability
in this UWMP is based on existing water rights, contractual entitlements, recycled water production, and
planned groundwater production. The City does not currently rely on additional short -term or long-term
water transfers or exchanges to meet projected normal-year demands identified in this UWMP.
The City participates in limited regional exchange and mutual aid arrangements that may provide
operational flexibility during emergencies or constrained supply conditions. The Whale Rock Commission,
of which the City is a member agency, has an agreement with the City of Morro Bay that provides a
framework for mutual aid during disruptions to water deliveries or lack of available water supplies. The City
also has an agreement with San Luis Obispo County Service Area No. 10A allowing for the exchange of
up to 50 acre-feet per year of Nacimiento water for water from Whale Rock Reservoir.
These agreements provide operational flexibility and emergency response options, but they are not
assumed to increase the City’s projected long-term water supply availability in this UWMP. The City may
evaluate future water transfer, exchange, or cooperative water management opportunities if they become
available and are consistent with applicable water rights, contractual obligations, infrastructure capacity,
treatment requirements, environmental requirements, and long-term water supply reliability objectives.
CHAPTER 7: WATER SERVICE RELIABILITY AND DROUGHT RISK
ASSESSMENT
7.1 Introduction
Chapter 7 evaluates the reliability of the City’s water supplies under the hydrologic conditions required by
the UWMP Act. The chapter includes both long-term water service reliability analysis and near-term drought
risk assessment.
Sections 7.4 through 7.6 evaluate long-term reliability under normal-year, single dry-year, and multiple dry-
year conditions using the demand forecasts described in Chapter 4 and the long-term water supply planning
values described in Chapter 6. These analyses evaluate whether the City’s existing and planned supplies
are sufficient to meet projected demands through the UWMP planning horizon.
Section 7.7 presents the five-year drought risk assessment, which is a near-term operational reliability
analysis supported by the City’s Water Projection Model. The five-year drought risk assessment evaluates
whether available supplies are sufficient during the near-term five-year drought risk period using current or
projected near-term conditions, including current reservoir storage, recent water use, current population
estimates, seasonal demand patterns, source availability, infrastructure constraints, groundwater project
status, recycled water availability, and dry-year assumptions.
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When conducting a drought risk assessment, if actual or projected conditions result in a water shortage,
the City would implement the shortage response actions identified in the Water Shortage Contingency Plan,
which is described in Chapter 8 and included as Appendix H.
7.2 Basis of Water Service Reliability Assessment
The City’s water service reliability analysis is based on projected water demands and projected water supply
availability for each required planning scenario. Because Chapter 7 includes both long -term reliability
analysis and near-term drought risk assessment, the City applies different methodologies based on the
purpose of each analysis.
For the long-term reliability assessments presented in Sections 7.4 through 7.6, the City uses the long-term
demand forecasts described in Chapter 4 and the long-term supply planning values described in Chapter
6. Long-term potable demand is based on the population methodology described in Section 3.6 and the
City’s 117 gpcd planning value. Long-term potable supply availability is based on established source -
specific planning values, including Nacimiento Reservoir contractual supply, the combined Salinas an d
Whale Rock Reservoir safe annual yield with the long-term siltation adjustment, and planned groundwater
production when available. Recycled water is evaluated separately as a non-potable supply that offsets
potable demand where recycled water service is available. This long-term method is consistent with the
General Plan and WWE and is intentionally conservative. It is used to evaluate supply sufficiency many
years into the future, when future population, customer water use, hydrologic conditions, regulat ory
requirements, infrastructure needs, climate conditions, and source availability may differ from current
conditions. The long-term method therefore provides a conservative planning basis for General Plan
consistency, infrastructure planning, and UWMP reliability analysis.
For the five-year drought risk assessment and upcoming single-year assessments, the City uses near-term
operational reliability analysis. This analysis is supported by the Water Projection Model and uses current
or projected near-term conditions, including reservoir storage, recent water use, current population
estimates, seasonal demand patterns, source-specific availability, infrastructure constraints, groundwater
project status, recycled water availability, and dry-year assumptions. This method is used because the
purpose of the five-year drought risk assessment and annual assessments is to determine whether the City
can meet expected near-term demands under reasonably anticipated operating conditions, not to evaluate
General Plan buildout demand.
Separate forecasting methodologies are used because long-term planning and near-term operational
analysis serve different purposes. Applying the General Plan demand methodology to near -term analyses
could overstate expected customer demand by using buildou t-oriented assumptions for a period when
actual population, recent water use, and current operating conditions are known with greater certainty.
Conversely, relying only on current demand for long-term planning could understate future needs and would
not provide the conservative basis needed for General Plan consistency and multi -decade water supply
planning.
7.3 Water Year Type Characterization
The UWMP Act requires urban water suppliers to evaluate water service reliability under normal-year, single
dry-year, and multiple dry-year conditions. For purposes of this UWMP, the City evaluates these conditions
using the source-specific planning assumptions described in Chapter 6, including the safe annual yield
analysis for Salinas and Whale Rock Reservoirs, Nacimiento Reservoir contractual supply reliability,
planned groundwater availability, recycled water availability, and known infrastructure constraints.
Because the City’s supply portfolio is based primarily on stored surface water and stored groundwater
supplies, availability is not characterized solely by selecting an average rainfall year or a single historical
dry year. Instead, the City applies assumptions that reflect how each source is planned and operated to
preserve supplies on a long-term basis. These assumptions are then applied to the UWMP’s required water
year types as described below.
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• Normal year: A normal year represents typical hydrologic and operational conditions used to
evaluate projected supply availability and demand. For the City, normal-year supplies are based
on adopted planning assumptions for each source, including the combined Salinas and Whale Rock
Reservoir safe annual yield, Nacimiento dependable yield, groundwater safe annual yield, and
recycled water availability.
• Single dry year: A single dry year represents one year of reduced hydrologic supply availability.
For water suppliers with surface water systems, this often includes reduced runoff, reduced
reservoir inflow, increased reliance on stored supplies, and the need to preserve r eservoir reliability
if dry conditions continue. For the City, these conditions are already reflected in the planning values
used for its primary surface water supplies. The Salinas and Whale Rock Reservoir supply is based
on safe annual yield modeling that evaluates the coordinated operation of the reservoirs through
historical hydrologic conditions, including drought periods. Nacimiento Reservoir supply availability
is based on the City’s contractual entitlement and prior dependable yield analyses that evaluated
the reliability of that supply during drought conditions. Because these dry -year effects are already
incorporated into the City’s surface water planning assumptions, the City does not apply a blanket
additional dry-year reduction to all supplies for the single dry-year scenario. However, to support
continued compliance with SGMA and avoid or minimize potential impacts to basin conditions and
interconnected surface waters, the City applies a reduction of available supply from 700 AFY to
300 AFY to available groundwater supplies during the single dry-year scenario.
• Multiple dry years: A multiple dry-year period represents five consecutive years of reduced
hydrologic supply availability. For water suppliers with surface water systems, this often includes
prolonged reductions in runoff and reservoir inflow, increased reliance on stored su pplies, and a
greater need to preserve long-term reservoir reliability. For the City, these conditions are already
reflected in the planning values used for its primary surface water supplies. The Salinas and Whale
Rock Reservoir supply is based on safe annual yield modeling that evaluates the coordinated
operation of the reservoirs through historical drought periods, including extended drought
conditions. Nacimiento Reservoir supply availability is based on the City’s contractual entitl ement
and prior dependable yield analyses that evaluated the reliability of that supply during drought
conditions. Because these drought-related effects are already incorporated into the City’s surface
water planning assumptions, the City does not apply a blanket additional dry-year reduction to all
supplies for the multiple dry-year scenario. However, to support continued compliance with SGMA
and avoid or minimize potential impacts to basin conditions and interconnected surface waters, the
City applies increasing annual reductions to available groundwater supplies during multiple dry -
year scenarios.
7.4 Normal-Year Water Service Reliability
Normal-year reliability compares projected water demand with projected available water supplies under
expected non-drought planning conditions. The City’s normal-year potable supplies include Salinas
Reservoir, Whale Rock Reservoir, Nacimiento Reservoir, and planned groundwater production. Recycled
water is evaluated separately as a non-potable supply.
The City’s normal-year reliability analysis demonstrates that projected potable supplies are sufficient to
meet projected potable demands through 2050, as shown in Table 7-1. The analysis also demonstrates
that projected recycled water supplies are sufficient to meet projected recycled water demands through
2050, as show in Table 7-2.
TABLE 7-1: NORMAL-YEAR POTABLE WATER RELIABILITY
Planning Year Potable Supply
(acre-feet)
Potable Demand
(acre-feet)
Potable
Surplus/Deficit
(acre-feet)
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2030 10,592 7,068 3,524
2035 10,592 7,496 3,096
2040 10,592 7,879 2,713
2045 10,592 8,281 2,311
2050 10,592 8,703 1,889
Notes: Demand values are based on the Section 3.6 population methodology and the City’s 117 gpcd
water demand planning value. Supply values are based on the long -term source availability and planning
assumptions described in Chapter 6.
TABLE 7-2: NORMAL-YEAR NON-POTABLE RELIABILITY
Planning Year
Non-Potable
Supply (acre-
feet)
Non-Potable
Demand
(acre-feet)
Non-Potable
Surplus/Deficit
(acre-feet)
2030 1,296 338 958
2035 1,296 388 908
2040 1,296 438 858
2045 1,296 488 808
2050 1,296 538 758
Notes:
7.5 Single Dry-Year Water Service Reliability
Single dry-year reliability evaluates the City’s ability to meet projected demands during one dry year. Dry -
year conditions may reduce runoff, reservoir inflows, or available surface water supply. The City’s supply
portfolio is designed to remain reliable under dry-year conditions through stored surface water supplies,
Nacimiento water, planned groundwater production, recycled water offsets, and demand management
measures as needed.
The City’s single dry-year analysis demonstrates that projected potable supplies are sufficient to meet
projected potable demands through 2050. Projected recycled water supplies are also sufficient to meet
projected recycled water demands through 2050, subject to the operational and regulatory considerations
described in Chapter 6. Single Dry-Year projections for the UWMP planning horizon can be seen in Table
7-1 and Table 7-2.
TABLE 7-3: SINGLE DRY-YEAR POTABLE WATER RELIABILITY
Planning Year Potable Supply
(acre-feet)
Potable Demand
(acre-feet)
Potable
Surplus/Deficit
(acre-feet)
2030 10,192 7,068 3,124
2035 10,192 7,496 2,696
2040 10,192 7,879 2,313
2045 10,192 8,281 1,911
2050 10,192 8,703 1,489
Notes: Demand values are based on the Section 3.6 population methodology and the City’s 117 gpcd
water demand planning value. Supply values are based on the long -term source availability and planning
assumptions described in Chapter 6.
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TABLE 7-4: SINGLE DRY-YEAR NON-POTABLE WATER RELIABILITY
Planning Year
Non-Potable
Supply (acre-
feet)
Non-Potable
Demand
(acre-feet)
Non-Potable
Surplus/Deficit
(acre-feet)
2030 1,296 371 925
2035 1,296 426 870
2040 1,296 481 815
2045 1,296 536 760
2050 1,296 591 705
Notes:
7.6 Multiple Dry-Year Water Service Reliability
Multiple dry-year reliability evaluates the City’s ability to meet projected demands during five consecutive
dry years. This analysis tests the City’s water supply portfolio under extended drought conditions and
determines whether projected supplies are sufficient over a multi-year dry period.
The City’s surface water planning assumptions are intended to preserve reliability over multiple years.
Salinas and Whale Rock Reservoir supplies are based on safe annual yield modeling that evaluates
reservoir operations over historical drought periods, including the extended 2006–2016 drought period.
Nacimiento supplies are based on the City’s contractual entitlement and reliability evaluations described in
Chapter 6. Planned groundwater production and recycled water supplies provide additional diversific ation
and operational flexibility, but their availability may vary under multiple dry -year conditions.
The City’s multiple dry-year analysis demonstrates that projected potable supplies are sufficient to meet
projected potable demands through 2050, as shown in Table 7-5. Projected recycled water supplies are
also sufficient to meet projected recycled water demands during the five-year dry sequence, as shown in
Table 7-6.
Groundwater availability is adjusted in the multiple dry -year analysis to reflect groundwater basin
management considerations and the City’s intent to avoid or minimize potential impacts to surface water
flows and other groundwater sustainability plan sustainable management criteria . Under normal planning
conditions, groundwater availability may be assumed at up to 700 acre-feet per year once groundwater is
available. During multiple dry-year planning scenarios, assumed groundwater availability is reduced to
volumes as low as 50 acre-feet per year. These reductions are reflected in the multiple dry -year reliability
tables.
TABLE 7-5: MULTIPLE DRY-YEAR POTABLE WATER RELIABILITY
2030 2035 2040 2045 2050
First year
Supply totals 10,192 10,192 10,192 10,192 10,192
Demand totals 7,068 7,496 7,879 8,281 8,703
Surplus/Deficit 3,124 2,696 2,313 1,911 1,489
Second year
Supply totals 10,092 10,092 10,092 10,092 10,092
Demand totals 7,139 7,571 7,958 8,364 8,790
Surplus/Deficit 2,953 2,521 2,134 1,728 1,302
Third year
Supply totals 10,042 10,042 10,042 10,042 10,042
Demand totals 7,210 7,647 8,037 8,447 8,878
Surplus/Deficit 2,832 2,395 2,005 1,595 1,164
Fourth year Supply totals 9,992 9,992 9,992 9,992 9,992
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Demand totals 7,283 7,724 8,118 8,532 8,967
Surplus/Deficit 2,709 2,268 1,874 1,460 1,025
Fifth year
Supply totals 9,942 9,942 9,942 9,942 9,942
Demand totals 7,355 7,801 8,199 8,617 9,056
Surplus/Deficit 2,587 2,141 1,743 1,325 886
Notes: Demand values are based on the Section 3.6 population methodology and the City’s
117 gpcd water demand planning value. Supply values are based on the long -term source
availability and planning assumptions described in Chapter 6.
TABLE 7-6: MULTIPLE DRY-YEAR NON-POTABLE WATER RELIABILITY
2030 2035 2040 2045 2050
First year
Supply totals 1,296 1,296 1,296 1,296 1,296
Demand totals 371 426 481 536 591
Surplus/Deficit 925 870 815 760 705
Second year
Supply totals 1,296 1,296 1,296 1,296 1,296
Demand totals 382 437 492 547 602
Surplus/Deficit 914 859 804 749 694
Third year
Supply totals 1,296 1,296 1,296 1,296 1,296
Demand totals 393 448 503 558 613
Surplus/Deficit 903 848 793 738 683
Fourth year
Supply totals 1,296 1,296 1,296 1,296 1,296
Demand totals 404 459 514 569 624
Surplus/Deficit 892 837 782 727 672
Fifth year
Supply totals 1,296 1,296 1,296 1,296 1,296
Demand totals 415 470 525 580 635
Surplus/Deficit 881 826 771 716 661
Notes:
7.7 Five-Year Drought Risk Assessment
The UWMP Act requires urban water suppliers to include a drought risk assessment that evaluates water
supply reliability for a five-consecutive-year drought period. For the 2025 UWMP, the five-year drought risk
assessment evaluates the City’s ability to me et projected demands during the near-term period from FY
2026-27 through FY 2030-31.
The five-year drought risk assessment is a near-term operational reliability analysis. Unlike the long-term
reliability tables presented in Sections 7.4 through 7.6, the five-year drought risk assessment does not use
General Plan buildout demand assumptions or the City’s 117 gpcd long-term water demand planning value
to estimate customer demand. Instead, the City uses its Water Projection Model and current or projected
near-term conditions to evaluate whether available supplies are sufficient during the fiv e-year drought risk
period. The Water Projection Model evaluates how current and projected near -term conditions may affect
the City’s ability to meet demands during the five-year drought risk period. Model inputs may include current
reservoir storage volumes, recent potable water use, current population estimates, recent seasonal
demand patterns, source-specific availability, dry-year hydrologic assumptions, Nacimiento conveyance
assumptions, groundwater project completion timing, recycled water availability, infrastructure constraints,
and applicable regulatory or operational limitations. The model provides an assessment of near -term water
supply availability and helps determine whether a shortage is anticipated and whether WSCP response
actions may be needed.
The five-year drought risk assessment considers historical drought hydrology, current and projected near -
term supply conditions, and locally applicable climate-related factors that could affect supplies or demands
during the assessment period. Climate change may affect the City’s water supplies through changes in
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precipitation timing, runoff efficiency, reservoir inflows, evaporation, drought duration and severity, wildfire
risk, watershed conditions, and source water quality. Climate-related demand effects may include changes
in seasonal irrigation demand, evapotranspiration, and customer water use patterns. These considerations
are incorporated qualitatively through the City’s selection of dry -year assumptions, evaluation of current
reservoir storage and source availability, assessment of infrastructure and operat ional constraints, and
ongoing use of the Water Projection Model.
The City does not apply a separate numerical climate change adjustment to projected demands or supplies
in the five-year drought risk assessment. Instead, the assessment uses current and projected near -term
conditions, drought-informed hydrologic assumptions, known infrastructure constraints, and source-specific
reliability information to evaluate potential shortage conditions.
For purposes of this five-year drought risk assessment, potable and non-potable supplies are evaluated
separately. Potable demands are compared against potable supplies available from Salinas Reservoir,
Whale Rock Reservoir, Nacimiento Reservoir, and planned groundwater production, as applicable during
the assessment period. Non-potable demands are compared against recycled water supplies available for
approved non-potable uses. Recycled water offsets potable demand where recycled water service is
available, feasible, and authorized, but it is not assumed to meet potable demands.
The five-year drought risk assessment incorporates known near -term conditions that may affect source
availability during the assessment period, including temporary Nacimiento transmission system
conveyance constraints, the anticipated timing of permanent Nacimiento pipeline repairs, the expected
timing of groundwater treatment and extraction facilities coming online, and other operational or
infrastructure limitations. As these conditions change, the City will reevaluate near -term supply availability
through the annual water supply and demand assessment process and implement the WSCP as needed.
As shown in Table 7-7 and Table 7-8, the City’s projected near-term supplies are sufficient to meet projected
potable and non-potable demands during the five-year drought risk assessment period. Based on the
assumptions used in this assessment, the City does not anticipate a water shortage during the five-year
drought risk assessment period. If actual conditions differ from the assumptions used in this assessment,
including changes in reservoir storage, hydrology, infrastructure availability, water quality, treatment
capacity, regulatory requirements, or customer demand, the City will re-evaluate water supply conditions
through its annual water supply and demand assessment process and implement the WSCP as needed.
Based on the assumptions used in this assessment, the City has sufficient supplies to meet projected
demands during the Five-Year Drought Risk Assessment period. Near-term reliability is supported by the
City’s diversified supply portfolio, local reservoir supplies, planned groundwater restoration, and recycled
water offsets. Drought Risk Assessment details for potable water and recycled water can be found in Table
7-7 and Table 7-8.
TABLE 7-7: FIVE-YEAR DROUGHT RISK ASSESSMENT - POTABLE WATER
Reporting Year Potable Demand Potable Supply Potable Surplus /
Shortage
FY 2026-27 5,355 6,481 1,126
FY 2027-28 5,451 10,357 4,906
FY 2028-29 5,506 10,307 4,801
FY 2029-30 5,561 10,257 4,696
FY 2030-31 5,616 10,207 4,591
Notes:
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TABLE 7-8: FIVE-YEAR DROUGHT RISK ASSESSMENT - NON-POTABLE WATER
Reporting Year Non-Potable Demand Non-Potable Supply Non-Potable Surplus /
Shortage
FY 2026-27 306 1,296 990
FY 2027-28 348 1,296 948
FY 2028-29 359 1,296 937
FY 2029-30 370 1,296 926
FY 2030-31 381 1,296 915
Notes:
7.8 Reliability Findings and Relationship to the WSCP
The water service reliability analysis demonstrates that the City’s projected potable supplies are sufficient
to meet projected potable demands under normal-year, single dry-year, and multiple dry-year conditions
through 2050. The analysis also demonstrates that projected recycled water supplies are sufficient to meet
projected recycled water demands through 2050.
The City’s reliability is supported by a diversified supply portfolio that includes local surface water supplies,
planned groundwater production, and recycled water. The City’s use of conservative planning assumptions,
including the safe annual yield for Salinas and Whale Rock Reservoirs, the long-term siltation planning
adjustment, drought-representative modeling, source-specific groundwater adjustments, and the separate
evaluation of recycled water as a non-potable supply, provides a reasonable basis for evaluating long-term
reliability.
Although this chapter demonstrates projected supply sufficiency, actual conditions may differ from the
assumptions used in the UWMP. Potential causes of reduced supply availability include extended drought,
infrastructure failure, wildfire or watershed disturbance, water quality impacts, regulatory changes,
treatment or conveyance limitations, groundwater production delays, groundwater basin management
constraints, reduced recycled water availability, or demand conditions that differ from projections. If su ch
conditions result in a projected or actual shortage, the City would implement the WSCP described in
Chapter 8.
The WSCP establishes the City’s shortage response framework, including shortage stages, demand
reduction actions, supply augmentation options, communication protocols, monitoring and reporting
procedures, and enforcement mechanisms. The WSCP allows the City to respond to changing conditions
while continuing to protect public health, safety, and essential water uses.
CHAPTER 8: WATER SHORTAGE CONTINGENCY PLANNING &
EMERGENCY SUPPLY RESILIENCY
8.1 Introduction
The City’s Water Shortage Contingency Plan (WSCP) provides the framework for identifying, declaring,
responding to, and recovering from water shortage conditions. A water shortage may result from drought,
infrastructure failure, seismic damage, wildfire impacts, water quality issues, regulatory limitations, power
outages, supply interruption, or other emergency conditions that affect the City’s ability to access, convey,
treat, or deliver water.
The UWMP Act requires urban water suppliers to prepare a WSCP that includes procedures for conducting
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an annual water supply and demand assessment, six standard water shortage levels, shortage response
actions, communication protocols, monitoring and reporting procedures, enforcement provisions, and other
actions necessary to address shortage conditions. The WSCP is adopted in coordination with the UWMP
and is included as an appendix to this Plan. Because the WSCP is intended to guide the City’s response
to actual or projected water shortage conditions, it may be reviewed separately from the UWMP and
updated over time as needed to reflect changes in State requirements, DWR guidance, City policy, water
supply conditions, system operations, or implementation experience.
The City’s WSCP is intended to function as an operational response plan. It does not replace the long-term
water supply reliability analysis presented in Chapter 7. Instead, the WSCP provides the response
framework the City would use if actual or projected near-term conditions indicate that available supplies
may be insufficient to meet expected demands. WSCP implementation is informed by near-term operational
reliability analysis, including current storage, recent water use, source availability, infrastruc ture constraints,
and the City’s Water Projection Model.
8.2 Potential Causes of Water Shortage Conditions
Water shortage conditions may result from a range of hydrologic, operational, infrastructure, regulatory, or
emergency conditions. While drought is often the primary long -term water supply reliability concern, the
City’s water supply availability could also be affected by conditions that limit the City’s ability to access,
convey, treat, or distribute otherwise available supplies.
Potential causes of water shortage conditions may include, but are not limited to:
• Prolonged drought or reduced runoff into surface water reservoirs;
• Damage to raw water transmission pipelines, pump stations, or other conveyance facilities;
• Seismic events that damage dams, reservoirs, pipelines, tanks, pump stations, treatment facilities,
or distribution system infrastructure;
• Wildfire impacts to watersheds, reservoir water quality, or treatment plant operations;
• Water quality conditions that reduce source availability or treatment capacity;
• Regulatory requirements affecting diversions, releases, discharges, or source operations;
• Power outages or energy supply constraints affecting pumping, treatment, or distribution;
• Treatment plant or distribution system failures; and
• Emergency conditions that increase water demand.
Because the City relies on multiple surface water reservoirs, raw water conveyance facilities, treatment
infrastructure, storage facilities, distribution system assets, recycled water facilities, and planned
groundwater infrastructure, water shortage planning must consider both the amount of water available from
each source and the City’s ability to physically deliver that water to customers. The WSCP provides the
City’s staged response framework for addressing actual or projected shortage conditions, regar dless of
whether the shortage is caused by drought, infrastructure limitations, emergency conditions, or another
supply interruption.
8.2.1 Seismic Risk Assessment and Mitigation
California Water Code section 10632.5(a) requires UWMPs to include a seismic risk assessment and
mitigation plan to assess and mitigate a water system’s seismic vulnerabilities. Pursuant to California Water
Code section 10632.5(c), an adopted Local Hazard Mitigation Plan or Multi-Jurisdictional Hazard Mitigation
Plan may be incorporated into a UWMP to satisfy this requirement if the plan addresses seismic risk.
In coordination with the County of San Luis Obispo and participating local agencies, the 2025-2030 San
Luis Obispo County Multi-Jurisdictional Hazard Mitigation Plan (MJHMP) was developed to assess regional
hazards, vulnerabilities, and mitigation strategies associated with natural and human -caused disasters. The
City of San Luis Obispo participated in the development of the MJHMP and incorporates the plan by
reference into this UWMP for purposes of complying with California Water Code section 10632.5.
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The MJHMP evaluates earthquake hazards, liquefaction susceptibility, critical facility vulnerabilities, utility
system impacts, and infrastructure mitigation strategies applicable to the City and surrounding region. The
MJHMP also identifies potential impacts to utility infrastructure, including water transmission pipelines,
storage facilities, pump stations, treatment facilities, and related systems that could be affected by seismic
activity. Accordingly, the MJHMP also identifies mitigation measures intended to improve infrastructure
resilience and emergency preparedness, including capital improvements, emergency response
coordination, infrastructure assessments, redundancy planning, and continued incorporation of seismic
considerations into facility design and maintenance activities. The City uses information contained in the
MJHMP to support emergency preparedness planning, capital improvement prioritization, infrastructure
resiliency efforts, and interagency coordination during emergency response and rec overy activities.
The City’s water system also benefits from operational flexibility associated with multiple water supply
sources, interconnected transmission facilities, emergency storage, backup power capabilities, mutual aid
coordination, and emergency response procedures maintained through the Utilities Branch’s Emergency
Operations Plan and related emergency response programs. These measures support the City’s ability to
prepare for, respond to, and recover from seismic events and other emergency conditions that could affect
water service.
The 2025-2030 San Luis Obispo County MJHMP is incorporated by reference into this UWMP and may be
amended or updated independently of the UWMP process in accordance with applicable federal, state, and
local requirements.
8.3 City Water Shortage Contingency Plan
The City’s WSCP is included as Appendix H to the 2025 UWMP. The WSCP establishes the procedures
and response actions the City would use to address water shortage conditions. It includes the City’s annual
assessment process, shortage stage framework, shortage response actions, communication procedures,
enforcement provisions, revenue and expenditure considerations, monitoring and reporting procedures,
and procedures for responding to catastrophic supply interruptions.
The WSCP includes six shortage stages that correspond to progressively increasing levels of water supply
shortage. These stages are intended to provide a structured framework for escalating response actions as
supply conditions worsen. The stages are gener ally aligned with shortage levels of up to 10 percent, 10 to
20 percent, 20 to 30 percent, 30 to 40 percent, 40 to 50 percent, and greater than 50 percent. The specific
response actions implemented during a shortage would depend on the cause, severity, dur ation, timing,
and expected progression of the shortage.
The City evaluates near-term water supply conditions through its annual water supply and demand
assessment process. This assessment considers current and projected near -term demands, source-
specific supply availability, reservoir storage, hydrologic conditions, infrastructure constraints, treatment
and conveyance limitations, recycled water availability, groundwater project status, and other relevant
operational conditions. The assessment is supported by the City’s Water Projection Model, which helps
evaluate the City’s ability to meet expected demands under actual or projected near -term conditions.
If the annual assessment or another operational evaluation indicates that available supplies may be
insufficient to meet expected demands, City staff would evaluate the appropriate WSCP stage and
recommended response actions. The City Council would declare the applicable water shortage stage and
authorize implementation of specific shortage response actions through resolution, ordinance, or other
appropriate action. The City may also implement emergency response actions as needed if a sudden supply
interruption, infrastructure failure, water quality issue, or other emergency require d immediate action.
WSCP response actions may include public outreach and education, voluntary or mandatory conservation
measures, outdoor irrigation restrictions, restrictions on water waste, limitations on certain discretionary
uses of water, expanded monitoring and reporti ng, increased enforcement, drought rates or financial
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response measures, and other actions necessary to reduce demand or protect public health and safety.
The City may tailor response actions to the specific circumstances of a shortage and is not required to
implement every action listed in the WSCP during every shortage event.
The WSCP is intended to remain flexible and implementable. Because water shortages may result from
different causes, the City must retain the ability to adjust response actions based on the nature of the
shortage. For example, a drought-related shortage may require sustained demand reduction over an
extended period, while an infrastructure failure may require targeted short-term restrictions, emergency
repairs, temporary supply measures, or localized operational changes. The WSCP provides the framework
for these decisions while preserving City Council discretion to respond to actual conditions.
8.4 Water Shortage Contingency Plan Adoption, Submittal, and Availability
The City’s WSCP was adopted by the City Council alongside the 2025 UWMP on June 16, 2026 by
Resolution No.______. The adopted WSCP is included as Appendix H to this UWMP.
Following adoption, the City will submit the WSCP to DWR together with the adopted UWMP through the
required online submittal process. The City will also make the adopted WSCP available for public review
on the City’s website and at applicable City offices, consistent with UWMP Act requirements.
Because the WSCP may need to be updated more frequently than the UWMP, the City may amend the
WSCP independently of the UWMP if needed to respond to changes in State law, DWR guidance, City
policy, water supply conditions, system operations, emergency response procedures, or implementation
experience. Any future amendment to the WSCP would be completed in accordance with applicable legal
requirements, including public noticing, City Council consideration, and submittal to DWR as required.
CHAPTER 9: DEMAND MANAGEMENT MEASURES
9.1 Introduction
Demand management measures are water conservation programs, policies, incentives, operational
practices, and regulatory measures that reduce water waste and promote the reasonable and efficient use
of available water supplies. Demand management is an important component of the City’s long-term water
supply strategy because it helps reduce potable water demands, improve drought resilience, support
compliance with State water use efficiency requirements, and extend the reliability of existing supplies.
The City’s water conservation program supports both long-term water supply reliability and day-to-day
customer water use efficiency. The program includes operational measures such as metering, billing data
review, Advanced Metering Infrastructure, water loss control, and recycled water use; customer-oriented
measures such as outreach, audits, rebates, complimentary devices, and landscape water budgets; and
regulatory measures such as water waste enforcement, plumbing retrofit requirements, Model Water
Efficient Landscape Ordinance implementation, Urban Water Use Objective reporting, and UWMP and
Water Shortage Contingency Plan compliance.
The City’s demand management measures are guided in part by the City’s 2023 Water Conservation and
Efficiency Plan. That plan provides a proactive framework for reducing water demand, improving water use
efficiency, reducing water loss and waste, and supporting responsible land management practices. The
2023 plan distinguishes these proactive conservation efforts from the City’s Water Shortage Contingency
Plan, which identifies actions taken in response to drought or other shortage conditions.
This chapter describes the City’s demand management measures and summarizes the nature and extent
of implementation during the 2021 through 2025 UWMP reporting period, consistent with Water Code
section 10631(e). The measures described in this chapter support the water demand projections presented
in Chapter 4, the water supply reliability analysis presented in Chapter 7, and the shortage response
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framework described in Chapter 8.
9.2 Water Conservation Program Goals and Objectives
The City’s water conservation program is intended to support reliable water service, reduce unnecessary
water use, comply with State and federal requirements, and promote responsible water use practices
throughout the community. The City’s 2023 Water Conservation and Efficiency Plan identifies five primary
objectives:
1. Develop cost-effective water conservation measures that maximize opportunities to meet the future
water needs of the community;
2. Offset or delay the need to construct additional water supplies or upsize treatment and distribution
infrastructure;
3. Offset or reduce ratepayer costs associated with the treatment and delivery of safe drinking water
and the treatment of wastewater;
4. Meet applicable State and federal water conservation mandates; and
5. Foster environmental stewardship through responsible and innovative water use practices.
These objectives reflect the City’s approach to conservation as both a long -term water supply reliability
strategy and a practical tool for improving day-to-day water use efficiency. By reducing inefficient water use
and improving the City’s ability to understand customer demand patterns, the City can better manage
existing supplies, improve system resiliency, and support sustainable community growth.
9.3 Historical Conservation Efforts
Water conservation has been a core component of the City’s water management strategy for decades.
Conservation was first referenced in the City’s water management policies in 1973, and in 1985 the City
adopted the Annual Water Operational Plan policy, which identified conservation as a tool for extending
available supplies during projected water shortages. Since that time, conservation has evolved from a
primarily drought-response measure into an ongoing water resource management strategy that supports
long-term supply reliability, infrastructure planning, regulatory compliance, and responsible water use.
The City’s conservation program has historically included a combination of regulatory requirements,
customer assistance programs, operational practices, and public education. These efforts have included
water waste prohibitions, water use surveys and audits, plumbing fixture replacement requirements, public
outreach, conservation-oriented pricing, recycled water use, landscape water efficiency standards, water
loss auditing, meter replacement, and customer assistance programs. Together, these measures have
helped reduce inefficient water use while allowing the City to continue meeting community water needs.
The effectiveness of the City’s long-term conservation efforts is reflected in the City’s water use trends. The
City’s 2023 Water Conservation and Efficiency Plan notes that total water demand has not increased at the
same rate as population growth, and that community-wide water use declined from a high of approximately
182 gallons per capita per day in 1987 to approximately 92 gallons per capita per day in FY 2023. The 2023
Water Conservation and Efficiency Plan received Platinum recognition from the Allia nce for Water
Efficiency, the highest recognition level available, reflecting the City’s continued commitment to
comprehensive and forward-looking conservation planning.
This history demonstrates that conservation is not only a temporary response to drought or shortage
conditions. For the City, conservation functions as a continuing water supply reliability strategy by reducing
avoidable demand, preserving stored supplies, delaying or reducing the need for new infrastructure,
supporting regulatory compliance, and helping customers use water efficiently under both normal and dry -
year conditions.
9.4 Demand Management Measure Implementation (2021-2025)
The UWMP Act requires retail urban water suppliers to describe the nature and extent of demand
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management measures implemented during the prior five years. For the 2025 UWMP, this reporting period
covers 2021 through 2025. The required demand management measure categories include water waste
prevention ordinances, metering, consumption-based pricing, public education and outreach, programs to
assess and manage distribution system loss es, water conservation program coordination and staffing
support, and other significant demand management measures.
During the 2021 through 2025 reporting period, the City continued implementing a broad conservation
program intended to reduce water waste, improve customer water use efficiency, support regulatory
compliance, and maintain long-term water supply reliability. These efforts included ongoing water waste
enforcement, customer water use reviews, public outreach, recycled water program management,
consumption-based rates, landscape efficiency review, water loss auditing, meter replacement, and
implementation planning for Advanced Metering Infrastructure.
The City also advanced programs to prepare for new State water use efficiency requirements, including
Urban Water Use Objective reporting, commercial, industrial, and institutional performance measures,
dedicated irrigation meter tracking, large landscape water budgets, and future non-functional turf
implementation. These efforts are part of the State’s broader Making Conservation a California Way of Life
framework and are expected to shape the City’s conservation program over the next UWMP cycle.
The City’s 2023 Water Conservation and Efficiency Plan provided a more detailed evaluation of long -term
conservation measures using the Alliance for Water Efficiency Conservation Tracker Tool. The plan
evaluated potential water savings, costs, staffing needs, and customer participation opportunities, and
identified a conservation program intended to maximize practical water savings using available funding and
staff resources. The City’s subsequent conservation program planning has focused on implementation of
selected measures, refinement of conservation review methods, rebate program adjustments,
Waterfluence landscape budgets, AMI rollout, land-based demand projections, MWELO reporting, and
preparation for UWUO and water loss reporting.
TABLE 9-1: DEMAND MANAGEMENT MEASURE IMPLEMENTATION SUMMARY (2021-2025)
Demand Management
Measure Implementation During 2021-2025 Planned Continuation
Water Waste Prohibition
Continued enforcement of water waste prohibitions
and response to suspected leaks, runoff, and
inefficient use.
Continue; update
procedures as needed.
Metering and AMI Continued monthly metering and billing; advanced
phased AMI implementation.
Continue AMI rollout and
customer data
improvements.
Consumption-Based Pricing
Continued use of metered, consumption-based
water rates developed through cost-of-service
principles.
Continue future cost-of-
service review and rate
updates.
Public Education and
Outreach
Continued use of website information, direct
customer communication, public outreach,
conservation messaging, and program promotion.
Continue and tailor
outreach for AMI, CII,
UWUO, and non-
functional turf.
Distribution System Loss
Reduction
Continued annual water loss audits, infrastructure
replacement, meter replacement, leak detection,
and water loss control activities.
Continue and integrate
AMI data as available.
Program Coordination and
Staffing
Continued conservation program coordination
across Water Resources, Utility Billing, Water
Distribution, and Planning sections/functions.
Continue coordinated
implementation and
reporting.
Other Significant DMMs
Continued recycled water program, rebates,
complimentary devices, customer audits,
plumbing retrofit, MWELO, and landscape water
budgets.
Continue and refine
based on cost-
effectiveness,
participation, and
regulatory needs.
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9.5 Water Waste Prevention Ordinances
The City’s water waste prevention requirements are a core component of its demand management
program. Water waste prevention helps reduce unnecessary demand, supports responsible use of potable
supplies, and provides the City with a regulatory mechanism to respond to inefficient or unreasonable water
use.
The City’s Municipal Code prohibits water waste, including waste caused by leaks, faulty fixtures, excessive
irrigation, and runoff. City staff respond to reports of water waste, review potential violations, conduct field
inspections when needed, and work with customers to correct inefficient or wasteful water use. Water waste
response is intended to achieve correction through education and customer assistance whenever practical,
while retaining enforcement authority when voluntary compliance is not achieve d.
The City’s water waste regulations also support implementation of the City’s WSCP during water shortage
conditions. While water waste prohibitions apply during normal conditions, additional restrictions may be
implemented during declared shortage stages to reduce demand and protect available supplies.
9.6 Metering, Billing, and Advanced Metering Infrastructure
The City meters potable and non-potable water service connections and uses metered consumption data
for billing, customer service, water conservation, water loss auditing, and demand forecasting. Metering
supports conservation by linking water use to customer billing and by providing the data needed to identify
leaks, high-use accounts, and unusual consumption patterns. The City also meters water supply sources,
including surface water, groundwater, and recycled water sources, which supports system -wide water
accounting and water loss analysis.
The City reads and bills meters monthly. Monthly billing data provides a regular source of customer
consumption information and allows the City to identify potential leaks or abnormal consumption through
routine billing and consumption reviews.
The City has begun implementing Advanced Metering Infrastructure (AMI) to improve water use monitoring,
leak detection, customer service, and demand management. AMI will provide more timely and granular
water use data, improve the City’s ability to identify continuous use and potential leaks, reduce inefficiencies
associated with manual meter reading, and provide customers with better access to water use information.
It is anticipated that the addition of AMI capabilities will result in significant behavioral changes to water use
within a customer’s home due to added oversight and awareness by water users.
As of 2025, approximately 5,000 meters had been equipped with radio communication endpoints as part of
the City’s phased transition to a full AMI system, which is anticipated to be completed in 202 8.
9.7 Conservation Pricing and Water Rate Structure
The City uses metered, consumption-based water rates for monthly water and sewer billings. Consumption-
based rates support water use efficiency by charging customers based on the amount of water used and
by reinforcing the relationship between water use and the total cost of water service. The City’s water rates
are developed through cost-of-service analysis and adopted through applicable public review and approval
processes. Water rate setting must be consistent with cost-of-service requirements and applicable law,
including Proposition 218. The City will continue to evaluate water rates through future cost-of-service
studies to ensure that rates recover the cost of providing water service, remain legally defensible, and
support efficient water use.
9.8 Public Education, Outreach, and Technical Assistance
Public education and outreach are important tools for promoting water conservation, preventing water
waste, and helping customers understand how to use water efficiently. The City has used public education
and outreach to support conservation since the 1970s. Public outreach is used to support both ongoing
conservation and implementation of new conservation-related regulatory requirements. During normal
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conditions, outreach may focus on efficient irrigation, leak detection, fixture efficiency, recycled water,
landscape efficiency, rebates, complimentary devices, and responsible water use. During water shortage
conditions, outreach may also include information about shortage stages, restrictions, enforcement,
conservation targets, and available customer assistance.
The City’s outreach methods include website updates, City news articles, e -notifications, attendance at
local events, informational materials, newsletters, social media advertising, welcome emails for new
customers, billing inserts, online how-to videos, direct mail campaigns, and meetings with business groups
and homeowners associations. The City is also expanding outreach to support commercial, industrial, and
institutional water use efficiency. Planned and ongoing efforts include contacting high -use CII customers,
identifying large landscapes, providing information about rebates and complimentary devices, and directing
customers to irrigation scheduling training and water efficiency resources.
9.9 Programs to Assess and Manage Distribution System Losses
The City has completed annual AWWA water loss audits since 2009 and conducts annual water loss audits
and implements programs to reduce real and apparent losses within the potable water distribution system.
Water loss management supports water supply reliability by reducing avoidable losses, improving system
efficiency, and helping prioritize infrastructure replacement and maintenance.
The City’s water loss control efforts include service line replacement, meter replacement, valve exercising
to ensure effective system isolation during emergency leak repairs , capital project planning and delivery,
acoustic leak detection, meter testing and calibration, and regularly scheduled billing audits.
The City will continue to reduce real and apparent losses through the measures outlined above and through
expansion of its AMI infrastructure. Chapter 4 provides additional information regarding the City’s reported
distribution system water loss.
9.10 Water Conservation Program Coordination and Staffing
The City’s demand management measures are implemented through coordination among multiple Utilities
work groups. Water Resources staff coordinate conservation planning, customer outreach, water waste
response, conservation reviews, regulatory reporting, MW ELO support, rebate and complimentary device
programs, recycled water coordination, and long-term demand management planning. Utility Billing
supports meter reading, billing review, customer account data, and customer communication. Water
Distribution supports meter replacement, AMI implementation, leak detection, water loss control, valve
exercising, and infrastructure maintenance.
The City’s Water Resources section, which leads the water conservation programs, is staffed by the Water
Resources Program Manager, Water Conservation Specialist, Water Resource Technician, Recycled
Water Specialist. Program responsibilities include UWMP and WSCP work, water supply and demand
assessments, conservation reporting, UWUO work, water loss reporting, AMI coordination, MWELO
reviews, rebate program administration, conservation reviews, public outreach, plumbing retrofit reviews,
complimentary devices, water waste violations, Waterfluence budget development, and recycled water
program implementation.
This coordinated staffing approach allows the City to connect customer-facing conservation programs with
utility operations, billing, recycled water management, regulatory compliance, and long-term planning. The
City may also use professional services, regional partnerships, or consultant support for specialized
program needs such as land-based demand projections, outreach campaigns, irrigation system training,
water loss validation, regulatory reporting, or conservation program evaluation.
9.11 Other Significant Demand Management Measures
In addition to the demand management measure categories described above, the City implements other
programs that have a significant effect on water use and long-term water supply reliability, as noted below.
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9.11.1 Recycled Water Use
Recycled water offsets potable water use for approved non-potable applications and is an important
component of the City’s demand management strategy. The City has used recycled water as part of its
water supply portfolio since 2006. Recycled water is used primarily for landscape irrigation and construction
water, and it provides a local, non-potable supply that is less dependent on surface reservoir inflows than
the City’s potable surface water supplies. The City serves recycled water to over 50 recycled water users
in the City. Each site is required to have a site supervisor who receives training and completes quarterly
reports identifying water waste runoff and system deficiencies. In total, recycled water accounts for
approximately five percent of the City’s water demand each year, offsetting water demand from local
reservoirs.
9.11.2 Conservation Reviews, Audits, and Customer Support
The City provides water conservation-related assistance to residential and non-residential customers who
have high water use, suspected leaks, water waste violations, or an interest in reducing water consumption.
Staff may review historical water use, evaluate property conditions, confirm meter func tionality, identify
potential leaks, review irrigation practices, and provide information on low -flow fixtures and other water
saving opportunities.
Staff typically attempt to work with customers by phone or email first after discovering abnormal water use
at a property. If staff are unable to contact the customer, staff may conduct a site visit and make contact in
person or leave a door hanger if unable to make personal contact. The City’s newer conservation program
planning efforts include streamlining monthly conservation reviews through automated calls or pre -set
emails, proactively providing monthly water use data to certain buildings and large lan dscapes, and
annually contacting or scheduling site visits with high -use commercial customers. These contacts may
include information about high-use status, current rebates, complimentary items, cost-effectiveness tools,
and irrigation scheduling training.
9.11.3 Complimentary Devices and Rebate Programs
The City provides complimentary water conservation devices to help customers reduce inefficient water
use. Complimentary devices include items such as low-flow showerheads, faucet aerators, flow meter bags,
five-minute shower timers, dish squeegees, leak detection dye tablets, hose nozzles, soil moisture meters,
water conservation posters, and lawn signs.
Additionally, the City uses rebates and financial incentives to encourage customers to replace inefficient
fixtures, equipment, irrigation systems, or other water -using devices with more efficient alternatives. In
2022, the City Council authorized $30,000 to launch an up dated rebate program. Beginning in 2023, the
City offered rebates for high-efficiency toilets and urinals, large landscape smart irrigation controllers, and
water-efficient restaurant dipper wells. Rebate funding was allocated among single -family residential, multi-
family residential, and CII account holders to support equitable access to program funds. For a period the
City also entered into a partnership with Rachio through the California Water Efficiency Partnership to offer
discounted smart irrigation controllers to single-family residential customers.
The City’s plumbing retrofit program has been in place since the 1990s. This program has helped to create
long-term indoor water savings by requiring inefficient fixtures to be replaced over time. The City adopted
plumbing retrofit regulations in 1992 requiring existing residential and CII structures to be retrofitted with
low-water-use plumbing fixtures upon sale, change of use, or expansion of use. The program was most
recently amended on December 7, 2021, to require indoor toilets, faucets, showerheads, and urinals to
meet California Civil Code section 1101.3. The City documents the use of this program through an online
mapping tool showing properties certified as having low-flow fixtures. This program has reduced the City’s
long-term water demand by an estimated 1,500 acre-feet per year since its inception.
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9.11.4 MWELO, Landscape Water Budgets, and CII Water Use
Landscape water use remains an important focus of the City’s demand management program. The City
implements water-efficient landscape requirements through the plan review process for new development.
These requirements help reduce irrigation demand by requiring efficient irrigation systems, appropriate
plant selection, water budgets, and landscape documentation for applicable projects. Landscapes adhering
to MWELO irrigation requirements are estimated to use 80 percent less water than traditional landscapes .
For its existing customer base, the City is developing and implementing landscape water budgets for City
parks, recycled water sites, and selected CII properties with dedicated irrigation meters. These budgets will
help identify customers that are over budget and allow the City to offer assistance to improve irrigation
system performance and management.
Additionally, staff are in the beginning stages of drafting a plan to support the community with the State of
California’s Non-Functional Turf Irrigation Ban. This state-mandated regulation is anticipated to reduce
irrigation demand for existing CII accounts as restrictions on the use of potable water for irrigating non -
functional turf are phased in beginning in 2027. The non-functional turf restrictions apply to turf that is
ornamental and not regularly used for recreation, civic, or community purposes. Th e restrictions do not
prohibit irrigation of functional turf, such as sports fields, school fields, picnic areas, or other turf areas
regularly used for recreation or public gathering, and they do not prohibit irrigation of trees or other non -turf
plantings. The restrictions also apply only to potable water irrigation and do not prohibit the use of recycled
water where recycled water service is available and otherwise authorized. The City’s implementation
approach is expected to include identification of potentially affected properties, communication with CII
customers and large landscape customers, stakeholder meetings, direct mail or electronic notices,
customer assistance, and coordination with related City programs. Where necessary, the City may also
coordinate with urban forestry, stormwater, sustainability, and regional water conservation partners to
support turf conversion, climate-ready landscaping, tree preservation, green infrastructure, and irrigation
scheduling training. These efforts are intended to help customers comply with State requirements while
reducing potable irrigation demand and supporting broader community sustainability goals .
9.12 Planned Demand Management Measures and Performance Tracking
The City will continue implementing demand management measures to support long-term water supply
reliability, reduce avoidable water waste, and comply with evolving State water use efficiency requirements.
Planned demand management efforts include all of the City’s current DMMs, with additional measures as
the City completes its AMI implementation.
The City’s planned conservation efforts are informed by the 2023 Water Conservation and Efficiency Plan,
which evaluated long-term conservation measures using the Alliance for Water Efficiency Conservation
Tracker Tool. The plan evaluated water savings pot ential, cost-effectiveness, staffing needs, available
funding, and public input to identify a practical water conservation program that could be implemented using
available City resources. The plan emphasizes conservation as one of the City’s most cost -effective tools
for meeting current and future water needs while reducing pressure on water supplies, treatment facilities,
and distribution infrastructure.
Over the first 5-year UWMP planning period (2026-2030), the City expects to focus on measures that
improve both customer water use efficiency and the City’s ability to understand and manage demand.
These efforts may include continued deployment of AMI, expanded use of customer water use data,
refinement of conservation review procedures, implementation of landscape water budgeting tools, updated
rebate and complimentary device programs, continued water loss reporting, and development of customer
support programs related to CII water use efficiency and non-functional turf restrictions.
The City’s conservation program planning also identifies several near -term priorities related to new State
requirements, including Urban Water Use Objective reporting, water loss reporting, CII best management
practices, disclosable building water use data requests, large landscape tracking, and non-functional turf
implementation. These efforts are expected to require continued coordination among Water Resources,
Utility Billing, Water Distribution, recycled water staff, Community Development, Sustainabilit y, Urban
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Forestry, Stormwater, and regional conservation partners.
The City will also continue to track program effectiveness using performance measures. Key performance
indicators may include:
1. Monthly Citywide GPCD and residential GPCD;
2. Monthly water use for high-use CII and residential properties;
3. Monthly water use for CII dedicated irrigation meters, large landscapes, and disclosable buildings;
4. Actual urban water use compared with the calculated Urban Water Use Objective;
5. Estimated real water losses in gallons per connection per day; and
6. Participation in workshops, programs, rebates, and complimentary device offerings.
These performance indicators will help the City evaluate whether conservation measures are effective,
identify customers or sectors that may benefit from additional outreach or technical assistance, support
State reporting requirements, and guide future pr ogram adjustments. Performance tracking will become
increasingly important as AMI implementation progresses and more detailed customer water use data
becomes available.
9.13 Relationship to Water Supply Reliability and Shortage Planning
The City’s demand management measures support both long-term water supply reliability and short-term
shortage response. During normal conditions, conservation programs reduce avoidable demand, improve
customer water use efficiency, reduce system losses, and help preserve stored supplies. These ongoing
savings support the demand projections and supply reliability analysis presented in Chapters 4 and 7.
Demand management measures also provide a foundation for the City’s Water Shortage Contingency Plan.
Programs such as water waste enforcement, customer outreach, high -use customer review, irrigation
efficiency support, recycled water use, and landscape wat er budgeting can be expanded or intensified
during shortage conditions. This allows the City to build upon existing programs rather than creating entirely
new response measures during a drought or emergency.
The 2023 Water Conservation and Efficiency Plan distinguishes the City’s ongoing conservation efforts
from demand reduction measures identified in the WSCP by explaining that the conservation plan identifies
actions the City will take to conserve water on an ongoing basis, while the WSCP identifies actions that
may be implemented in response to various degrees of drought or water shortage. This distinct ion is
important because long-term conservation helps reduce baseline demand, while the WSCP provides the
staged response framework needed when additional temporary reductions are necessary.
CHAPTER 10: ADOPTION, SUBMITTAL, AND IMPLEMENTATION
10.1 Introduction
This chapter documents the City’s process for public review, adoption, submittal, and implementation of the
2025 UWMP and the 2025 WSCP. The UWMP Act requires urban water suppliers to provide notice, make
the plan available for public inspection, hold a public hearing, adopt the plan, submit the adopted plan to
the California Department of Water Resources, and make the adopted plan available for public review.
The City prepared the 2025 UWMP and 2025 WSCP in accordance with the Urban Water Management
Planning Act, applicable provisions of the California Water Code, and DWR’s 2025 UWMP Guidebook.
Documentation of the City’s notice, public hearing, adoption, and submittal process is included in Appendix
C.
10.2 Notice of Plan Preparation and Agency Coordination
California Water Code section 10621(b) requires an urban water supplier, at least 60 days before the public
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hearing on the plan, to notify any city or county within which the supplier provides water that the supplier is
reviewing the plan and considering amendments or changes. The City provided the required notice to
applicable agencies before the public hearing. This notice is provided in Appendix C.
10.3 Public Review Draft and Availability for Public Inspection
California Water Code section 10642 requires an urban water supplier to encourage active involvement of
diverse social, cultural, and economic elements of the population within the service area before and during
preparation of the plan. The section also requires the supplier to make the plan available for public
inspection and hold a public hearing before adoption.
The City made the Public Review Draft of the 2025 UWMP and WSCP available for public inspection before
the public hearing. The Public Review Draft was made available on June 1, 2026, through the City’s website
at www.slocity.org and the Utilities Branch’s website at https://www.slocity.org/government/department-
directory/utilities-department.
The City provided notice of the public hearing in accordance with Water Code section 10642 and applicable
noticing requirements. The public hearing notice identified the date, time, and location of the hearing and
the availability of the Public Review Draft.
Notice of the public hearing was published in [INSERT PUBLICATION] on [INSERT DATE(S)].
Copies of the public hearing notice and proof of publication are included in Appendix C.
10.4 Public Hearing and Adoption
The City provided opportunities for public participation and comments on the 2025 UWMP development at
a City Council public hearing on June 16, 2026. The City further encouraged involvement of the public
through its website, social media posts, and two public notices. Two public hearing notifications were
published in The New Times (the local area newspaper). A copy of the published notices are included in
Appendix C. The hearing process provided an opportunity for City water users and interested parties to
become familiar with the UWMP and ask questions regarding the City’s water resources and long-term
planning efforts. The process also allowed the public to provide comments regarding the City’s continued
efforts to maintain a reliable, safe, and high-quality water supply.
The City Council held a public hearing on June 16, 2026, to receive public comments and consider adoption
of the 2025 UWMP and WSCP. During the public hearing, the City Council considered the adoption of the
2025 UWMP and the 2025 WSCP, while receiving and filing the Annual Water Supply and Demand
Assessment. Following the public hearing, the City Council adopted the 2025 UWMP by Resolution No.
______ and the WSCP by Resolution No. ______.
The adopted resolution for the UWMP is included in Appendix C, while the adopted resolution for the
WSCP can be found in Appendix H.
10.5 Submittal of Adopted UWMP and WSCP
Following adoption, the City will submitted the adopted 2025 UWMP, WSCP, standardized tables, and
required supporting documentation to DWR through the WUEdata Portal. DWR requires 2025 UWMPs and
WSCPs to be submitted within 30 days of adoption and no later than July 1, 2026.
California Water Code section 10644 also requires submittal of the adopted UWMP and WSCP to the
California State Library and to applicable cities and counties within 30 days after adoption.
Table 10-1: Required Post-Adoption Submittals provides comprehensive documentation of all UWMP and
WSCP submittal requirements.
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TABLE 10-1: REQUIRED POST-ADOPTION SUBMITTALS
Requirement Recipient/Location Required Timing Date Submitted Method
Submit
Adopted
UWMP and
WSCP
California Department of
Water Resources
Within 30 days after
adoption and no later
than July 1, 2026
[TO BE ADDED
AFTER ADOPTION]
Online via
DWR’s
WUEdata Portal
Submit
adopted
UWMP and
WSCP
California State Library Within 30 days after
adoption
[TO BE ADDED
AFTER ADOPTION]
Submitted in
accordance with
State Library
filing
requirements
Submit
adopted
UWMP and
WSCP
County of San Luis
Obispo
Within 30 days after
adoption
[TO BE ADDED
AFTER ADOPTION] Email / Web Link
Make adopted
UWMP and
WSCP
available for
public review
Online at www.slocity.org
and printed at 879 Morro
Street, San Luis Obispo
Within 30 days after
filing with DWR
[TO BE ADDED
AFTER ADOPTION]
Posted online
and made
available for
review at 879
Morro Street,
San Luis Obispo
10.6 Public Availability After Filing
California Water Code section 10645 requires an urban water supplier, not later than 30 days after filing a
copy of its plan with DWR, to make the plan available for public review during normal business hours. After
filing the adopted 2025 UWMP and WSCP with DWR, the City will make the adopted documents available
for public review.
The adopted 2025 UWMP and WSCP will be made available on the City’s website at www.slocity.org and
during normal business hours at the Public Works and Utilities Department, Utilities Branch Administrative
Office at 879 Morro Street in San Luis Obispo, California. Because this action occurs after adoption and
filing with DWR, the final public availability date will be documented after filing is complete.
10.7 Plan Implementation
Implementation of the 2025 UWMP is the responsibility of the City’s Public Works and Utilities Department,
Utilities Branch. Key staff responsible for overseeing implementation include the Director of Public Works
and Utilities, Assistant Director of Utilities, Deputy Director of Utilities (Water), and Water Resources
Program Manager.
The UWMP is intended to serve as an ongoing water resources planning and management document that
supports long-term water supply reliability, regulatory compliance, infrastructure planning, and drought
preparedness. Information contained in the UWMP will be used to support future water resource planning
efforts, infrastructure investment decisions, environmental review processes, and ongoing evaluation of
water supply and demand conditions.
Annual updates regarding UWMP implementation, water supply conditions, and other water resource
issues are provided to the City Council as part of the City’s annual Water Supply and Demand Assessment
in accordance with the General Plan WWE Policy A5.3.1, and applicable California regulations. Additional
water supply planning and operational information is also documented in the City’s annual Water Supply
and Demand Assessment documents provided in Appendix F.
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California Water Code section 10643 requires an urban water supplier to implement the plan adopted
pursuant to the UWMP Act in accordance with the schedule set forth in the plan. The City will implement
the 2025 UWMP through the water supply planning, demand management, water shortage planning, and
reporting actions described in this plan.
Implementation actions include continued monitoring of water supply conditions, preparation of Annual
Water Supply and Demand Assessments, implementation of the WSCP when needed, implementation of
demand management measures, continued water loss reporting, recycled water planning, groundwater
project implementation, and future UWMP updates as required by the UWMP Act.
10.8 Amendments to the Adopted Plan
The UWMP Act allows an adopted UWMP to be amended. If the City amends the 2025 UWMP or WSCP
after adoption, the City will follow the applicable Water Code requirements for notice, public hearing,
adoption, submittal, and public availability.
The City may amend the UWMP or WSCP if significant changes occur in water supply availability, demand
projections, regulatory requirements, infrastructure conditions, land use assumptions, shortage response
actions, or other planning factors.
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APPENDICES
Appendix A – DWR Standardized Submittal Tables
No
Volume of
Water Supplied
2025
(AF)
4010009 City of San Luis Obispo 17,297 5,120
17,297 5,120
NOTES: Volume of water supplied includes potable water and recycled water.
Submittal Table 2-1 Retail: Public Water Systems
Total
Add additional rows as needed
DWR NOTES:
Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as
reported in Submittal Table 2-3. This table identifies the unit of measure selected in Table
2-3.
Has there been a change in the number of affiliated Public Water
Systems since the 2020 UWMP? (OPTIONAL)
Public Water System
Number
Public Water System
Name
Number of Municipal
Connections 2025
Water Supplier is also a member of a
SB X7-7 Regional Alliance
NOTES:
Name of Regional Alliance or
RUWMP (Drop Down List)
Submittal Table 2-2: Plan Identification
Select
One or
Both
Type of Plan
Individual UWMP
Regional Urban Water Management Plan
(RUWMP)
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Supplier is a wholesale supplier
Supplier is a retail supplier
UWMP Tables are in calendar years
UWMP Tables are in fiscal years
Unit AF
Submittal Table 2-3: Supplier Identification
Type of Supplier (select one or both)
Fiscal or Calendar Year (select one)
If using fiscal years provide month and date that the fiscal
year begins (mm/dd)
Units of measure used in UWMP
(Select from the drop down list).
7/1
DWR NOTES:
Units of measure (AF, CCF, MG) must remain consistent
throughout the UWMP as reported in Submittal Table 2-3.
NOTES:
Submittal Table 2-4 Retail: Water Supplier Information Exchange
Water Code Section 10631(h)
The retail Supplier has informed the following wholesale supplier(s) of
projected water use in accordance with Water Code Section 10631 (h).
Wholesale Water Supplier Name
Add additional rows as needed
San Luis Obispo County
NOTES:
10631(h) An urban water supplier that relies upon a wholesale agency for a
source of water shall provide the wholesale agency with water use projections
from that agency for that source of water in five-year increments to 20 years or
as far as data is available.
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2025 2030 2035 2040 2045 2050(opt)
49,849 53,934 57,200 60,118 63,184 66,407
Submittal Table 3-1 Retail: Population - Current and Projected
Water Code Section 10631(a)
Population
Served
NOTES: Population data for 2025 from State of California, Department of Finance, E-5
Population and Housing Estimates for Cities, Counties and the State. Population for
2030 and 2035 are based on City of San Luis Obispo General Plan Build Out
Projections. Population for 2040, 2045, and 2050 is developed utilizing a 1% annual
growth rate from from City 2035 build out population of 57,200.
Use Type
Volume
(AF)
Single Family Potable 1,917
Multi-Family Potable 1,193
Landscape Potable 306
Commercial Potable 944
Institutional/Governmental Potable 32
Industrial Potable 57
Distribution System Water Loss Potable 384
Landscape Recycled Water Non-Potable 243
Landscape Recycled Water - Golf Course Non-Potable 33
Commercial Recycled Water - Construction Non-Potable 12
Institutional/Governmental Recycled Water - Utilities Non-Potable 0
4833
288
5,120Total
Submittal Table 4-1 Retail: 2025 Actual Total Uses for Potable and Non-Potable Water
Water Code Section 10631(d)(1)
NOTES:
DWR NOTES: Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in
Submittal Table 2-3. This table identifies the unit of measure selected in Submittal Table 2-3.
2025 Actual Water Use
Add additional rows as needed
Level of Treatment
When Delivered
(OPTIONAL)
Drop down list
Additional Description
(as needed)
Drop down list
May select each use multiple times
These are the only use types that will be
recognized by the WUEdata online submittal tool
Subtotal Potable
Subtotal Non-Potable
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Use Type
2030 2035 2040 2045 2050 (opt)
(AF)(AF)(AF)(AF)(AF)
Single Family Potable 2,804 2,973 3,125 3,285 3,452
Multi-Family Potable 1,744 1,850 1,944 2,043 2,148
Landscape Potable 447 474 498 523 550
Commercial Potable 1,381 1,464 1,539 1,617 1,700
Institutional/Governmental Potable 84 89 93 98 103
Industrial Potable 47 50 52 55 58
Distribution System Water Loss Potable 562 596 627 659 692
Landscape Recycled Water Non-Potable 293 343 393 443 493
Landscape Recycled Water - Golf Course Non-Potable 33 33 33 33 33
Commercial Recycled Water -
Construction Non-Potable 12 12 12 12 12
Institutional/Governmental Recycled Water - Utilities Non-Potable 0.02 0.02 0.02 0.02 0.02
7,068 7,496 7,879 8,281 8,703
338 388 438 488 538
7,406 7,884 8,317 8,768 9,241
NOTES:
Total
DWR NOTES: Units of measure (AF, CCF, MG ) must remain consistent throughout the UWMP as reported in Submittal Table 2-3. This table identifies the unit of
measure selected in Submittal Table 2-3.
Subtotal Non-Potable
Subtotal Potable
Add additional rows as needed.
Drop down list
May select each use multiple times
These are the only Use Types that will be
recognized by the WUEdata online submittal tool
Additional Description
(as needed)Level of Treatment
When Delivered
(OPTIONAL)
Drop down list
Submittal Table 4-2 Retail: Total Uses of Potable, and Non-Potable Water - Projected
Water Code Section 10631(d)(1)
Projected Water Use
(Report To the Extent that Records are Available)
Are Future Water Savings Included in Projections?
(Refer to Appendix K of UWMP Guidebook)
Drop down list (y/n)
No
If "Yes" to above:
State the section or page number, in the cell to the right, where citations of
the codes, ordinances, or otherwise are utilized in demand projections are
found.
OPTIONAL Suppliers may complete Optional Submittal Table 4-4 R to quantify
the expected savings.
Are Lower Income Residential Demands Included In Projections?
(Refer to Appendix K of UWMP Guidebook)
Drop down list (y/n)
Yes
OPTIONAL If the method for accounting Lower Income Residential Demands
has been included, provide page number where this accounting can be found.
(An example is included in Appendix K.)
Submittal Table 4-3 Retail: Inclusion in Water Use Projections
Water Code Section 10631 (a), 10631 (d)(4)(A), and 10631 (d)(4)(B)
NOTES:
Page 367 of 476
DRAFT2025 Urban Water Management Plan
78
Public Water System ID #
Reported in Table 2-1 R Reporting Period
Submitted to DWR Water
Loss Audit Program
(yes/no)
2020 (CY)Yes
2021 (CY)Yes
2022 (CY)Yes
2022-23 (FY)Yes
2023-24 (FY)Yes
2024-25 (FY)Yes
Submittal Table 4-5 Retail: Water Loss Audit Reporting
Water Code Section 10631(d)(3)(A)
DWR NOTES: Suppliers will provide a link to the WUEdata submittals of their
Water Loss Audit Reports.
NOTES: The City submitted annual water loss audits on a calendar-year basis
for 2020, 2021, and 2022. Beginning with the 2022-23 reporting period, the City
transitioned to fiscal-year water loss audits to align with the City’s UWMP
reporting basis and other water supply planning documents. As a result, six
audit periods are shown in this table rather than five. Including all six audits
provides continuous coverage of the most recent five-year period while
documenting the City’s transition from calendar-year to fiscal-year reporting.
Report submittal status for all five years for each Public Water System as
available.
Add rows as needed
CA-4010009
Volume of Total Real
Loss (from AWWA
Water Loss Audit)
Volume of Total
Apparent Loss
(from AWWA Water
Loss Audit)
(AF)
(AF)
CA-4010009 Yes 17.7
Gallons per
Service
Connection per
Day (GPSCD)
17101 561.863 29.3 8.2
Gallons per
Service
Connection per
Day (GPSCD)
17101 89.98 4.7
Submittal Table 4-6 Retail: Progress Towards 2028 Water Loss Standard
Water Code Section 10631(d)(3)(C)
Public Water
System ID #
Reported in
Submittal Table 2-
1 R
Did the Water Board Calculate a Water
Loss Standard for this Public Water
System? (y/n)
If no, Supplier will not complete this
row.
Real Water Loss Apparent Water Loss
State Water Board Standard Most Recent AWWA Water Loss Audit
Real Water
Loss Per Unit
per Day
State Water Board Standard Most Recent AWWA Water Loss Audit
Apparent Water
Loss Per Unit per
Day
2028 Real Water Loss
Standard per Unit per
day
Units for Real
Water Loss
Drop down list
Number of Units
(Connections or
Miles corresponding
with units selected)
2028 Apparent
Water Loss Standard
per Unit per Day
Units for
Apparent Water
Loss
Number of
Connections
Add additional rows as needed.
Water Board's Calculated Water Loss Standards
DWR NOTES: Units of measure (AF, CCF, MG) for Water Loss MUST remain consistent with units reported in Submittal Table 2-3. The units reported in Submittal Table 2-3 are used in this table's calculations.
NOTES:
Page 368 of 476
DRAFT 2025 Urban Water Management Plan
79
Actual 2025 GPCD
(From SB X7-7
Compliance Form)
Did Supplier meet
the 2020 Target in
2025?
No Individual
Target 117 94 Yes NA
DWR NOTES:
Suppliers calculating a 2025 GPCD will need to complete and submit SB X 7-7 Compliance Tables to verify the use of SB X7-7
Methodologies.
Suppliers that were part of a merger or consolidation since 2020 see Chapter 5 and Appendix P for guidance.
NA=Not ApplicableNOTES:
Submittal Table 5-1 Retail: SB X7-7 2020 Target Progress
Water Code Section 10608.40
Check the box if the Supplier was not an Urban Water Supplier during or before the 2020 UWMP reporting cycle.
Proceed to the next table.
Was Supplier part
of a merger or
consolidation since
2020?
Regional
Alliance Target
or Individual
Target?
Drop down list
2020 Target Actual 2020
GPCD
Did Supplier
Achieve Targeted
Reduction for
2020?
Only for suppliers that did not meet
the Target in 2020
See DWR NOTES below.
2021 2022 2023 2024 2025
(AF) (AF) (AF) (AF) (AF)
0 0 0 0 0
Add additional rows as needed
Submittal Table 6-1 Retail: Groundwater Volume Pumped
Water Code Section 10631(4) and 10631(4)(c)
DWR NOTES:
Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in Submittal Table 2-3. This table
identifies the unit of measure selected in Submittal Table 2-3.
NOTES
Total
Check the box if the Supplier does not pump groundwater.
Proceed to the next table.
Check the box if all or part of the groundwater described below is desalinated. (OPTIONAL)
Groundwater Type
Drop Down List
May use each category
multiple times
Water Type
(OPTIONAL)
Drop down list
Location or Basin Name
Page 369 of 476
DRAFT2025 Urban Water Management Plan
80
100%
100%
Volume of
Wastewater
Collected from
UWMP Service
Area 2025
(AF)
City of San Luis Obispo Metered 4,488 San Luis Obispo WWTP, Place
ID 255380 Yes
4,488
Check the box if there is no wastewater collection system.
Proceed to the next table.
NOTES:
Submittal Table 6-2 Retail: Wastewater Collected Within Service Area in 2025
Water Code Section 10633(a)
Percentage of 2025 service area population served by wastewater collection
system (OPTIONAL)
Percentage of 2025 service area served by wastewater collection system
(OPTIONAL)
DWR NOTES: Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported
in Submittal Table 2-3. This table identifies the unit of measure selected in Submittal Table 2-3.
Additional Guidance. See Appendix M, Section M.21 for detailed guidance on this table.
Wastewater Collection Recipient of Collected Wastewater
Total Wastewater Received from UWMP
Service Area in 2025:
Wastewater
Volume
Metered or
Estimated?
OPTIONAL
Drop Down List
Name of Wastewater
Treatment Plant (WWTP) and
Place ID Number
Drop down list
Is WWTP
Located Within
UWMP Area?
Drop Down List
Add additional rows as needed
Name of Wastewater
Collection Agency
Volume Volume Volume Volume Volume
(AF)(AF)(AF)(AF)(AF)(AF)(AF)
San Luis Obispo
WWTP, Place ID Yes 4488 4,488 Tertiary 288 Tertiary 2408 Tertiary 1792
4,488 4,488 288 0 2,408 1,792 0
2025 Outcomes of Treated Wastewater
Check the box if no wastewater is treated or disposed of within the UWMP service area.
Proceed to the next table.
Does This
Plant Treat
Wastewater
Generated
Outside the
UWMP Service
Area?
(OPTIONAL)
Drop down list
Wastewater
Treatment Plant
Name and Place ID
Number
Drop down list
Treatment
Level
Drop down list
Treatment
Level
Drop down list
Treatment
Level
Drop down list
Treatment
Level
Drop down list
Treatment
Level
Drop down list
Name of other
entity
Total 2025
Volume of
Water
Treated
NOTES:
Total
2025 Volume
of Wastewater
Received from
UWMP Service
Area
(As Reported
in Submittal
Table 6-2 R )
Water Recycled Within
UWMP Service Area
(enter data as applicable)
Submittal Table 6-3 Retail: Wastewater Treatment and Outcomes Within UWMP Service Area in 2025
Water Code Section 10633(a)
DWR NOTES:
Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in Submittal Table 2-3. This table identifies the unit of measure selected in Submittal Table 2-3.
IPR: Indirect Potable Reuse would have the treatment level of its end use requrement in the Level of Treatment drop-down.
Additional Guidance. See Appendix M, Section M.21 for detailed guidance on this table.
Water Recycled Outside
of UWMP Service Area
(enter data as applicable)
Effluent Discharge that
is not a Permitted
Recycled Water Use
(enter data as applicable)
Required Discharge for
Instream Flow
(enter data as applicable)
Delivered to Another Entity for Additional
Treatment
(enter data as applicable)
Add additional rows as needed
Page 370 of 476
DRAFT 2025 Urban Water Management Plan
81
2025 2030 2035 2040 2045 2050 (opt)
(AF)(AF)(AF)(AF)(AF)(AF)Volume Narrative page number
(OPTIONAL)
Landscape irrigation (exc golf
courses)Non-Potable General Landscape
Irrigation Use 243 293 343 393 443 493 0
Golf course irrigation Non-Potable Golf Course Irrigation 33 33 33 33 33 33 0
Commercial use Non-Potable Construction Water 12 12 12 12 12 12 0
Other (Description Required)Non-Potable Water/Sewer Utility Use 0 0 0 0 0 0 0
288 338 388 438 488 538 0 0
Check box if recycled water is not used and is not planned for use within the service area of the supplier. The supplier will only complete the column
on "Potential Recycled Water Use" and submit an accompanying narrative on the feasibility of that potential recycled water use.
Submittal Table 6-4 Retail: Recycled Water Direct Beneficial Uses Within Service Area
Water Code Section 10633 (c)(e)
Total
Use Type
Drop down list
Water Type
(after treatment if
treated)
(OPTIONAL)
Drop down list
Additional Information
(as needed)
Potential Recycled Water Use
Add additional rows as needed
DWR NOTES: Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in Submittal Table 2-3. This table identifies the unit of measure selected in
Submittal Table 2-3.
Additional Guidance. See Appendix M, Section M.21 for detailed guidance on this table.
Potential recycled water use - a description of the feasibility of these uses must be included in the narrative.
Multiple Producers: If you have multiple recycled water producers, submit a separate table for each.
NOTES: Potential recycled water use volumes are represented as "0" in column J, as projected growth is included in volumes listed for 2025, 2030, 2035, 2040, 2045, and 2050.
San Luis Obispo WWTP, Place ID 255380
City of San Luis Obispo
Name(s) of Facility/ies Producing (Treating) the Recycled Water (OPTIONAL) :
Name of Supplier Operating the Recycled Water Distribution System (OPTIONAL) :
Supplemental Water Added in 2025 (volume) Include units (OPTIONAL) :
Source of 2025 Supplemental Water (OPTIONAL) :
2020 Projection
for 2025
2025 Actual
Use
(AF)(AF)
410 243
10 33
25 12
0 0
445 288
NOTES: Commercial use is water used for dust control and compaction on construction
sites. Other is water used by Utilities Department.
Total
DWR NOTES:
Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in
Submittal Table 2-3. This table identifies the unit of measure reported in Submittal Table 2-3
Additional Guidance. See Appendix M, Section M.21 for detailed guidance on this table.
Use Type
Drop Down list
Golf course irrigation
Commercial use
Other (Description Required)
Submittal Table 6-5 Retail: 2020 UWMP Recycled Water Use Projection
Compared to 2025 Actual
Water Code Section 10633 (e)
Check the box if recycled water was not used in 2025 nor
previously projected for use in 2020.
Proceed to the next table.
Add additional rows as needed
Landscape irrigation (exc golf courses)
Page 371 of 476
DRAFT2025 Urban Water Management Plan
82
Expected Increase in Recycled
Water Use
(AF)
Mandatory Use Ordinance Ordinance requiring use if developing within an
area that can be served recycled water 250
Sale of Seasonal Surplus Under Study
Potable Reuse Under Study
(AF)250
250
NOTES: The City has an adopted policy that that has been in place since it began utilizing recycled water requiring recycled water to be utilized
for new developments if it is available for use in the specific area. It is estimated that this ordinance will continue to increase recycled water
demand by 250 acre-feet through 2050. The City is in ongoing discussions with multiple parties related to the sale of surplus recycled water for
agricultural or environmental use, which could equal approximately 500 acre-feet per year. The volume of expected increases would be
dependent upon contract terms. The City is also continually examining the feasibility of potable reuse, volumes associated with such use
would depend upon whether the City pursued groundwater recharge or direct potable reuse. A groundwater recharge project could utilize up
to 1,000 acre-feet of water per year. Values for potable reuse and surplus sales are not included as these projects are uncertain.
Submittal Table 6-6 Retail: Methods to Encourage Future Recycled Water Use
Water Code Section 10633 (f)
Check the box if the Supplier does not plan to expand recycled water use in the future. Supplier will not complete
the table below but will provide narrative explanation.
Provide page location of narrative in the UWMP
Add additional rows as needed
Total
Name of Action Description
Unit Conversion to AF
Planned Implementation
Year
2006
Unknown
Unknown
51-52
(AF)
Groundwater Program No Potable 2028 All Year Types 50-700
Recycled Water
Expansion No Non-Potable 2026 Single-Dry Year 10 AF/Year
Additional Description
(as needed)
Water Type
(after treatment
if treated)
(OPTIONAL)
Drop Down list
Planned for Use
in Year Type
Drop Down List
NOTES:
Submittal Table 6-7 Retail: Expected Future Water Supply Projects or Programs
Water Code Section 10631 (f)
DWR NOTES:
Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in Submittal Table 2-3. This table identifies the unit of
measure reported in Submittal Table 2-3.
Check the box if some or all of the supplier's future water supply projects or programs are not compatible with this table and
are described in a narrative format.
Check the box if there are no expected future water supply projects or programs that provide a quantifiable increase to the
agency's water supply.
Procees to the next table.
Planned
Implementation
Year
Add additional rows as needed
Joint Project with other
suppliers?Expected
Increase in
Water Supply
to Supplier
(This may be a
range)
Provide page location of narrative in the UWMP
Name of Future
Projects or Programs Drop Down
List
(yes/no)
If Yes, Supplier Name
Page 372 of 476
DRAFT 2025 Urban Water Management Plan
83
Water Supply
Actual Volume
Total Entitlement
(OPTIONAL)
See "DWR Notes" below
(AF)(AF)
Surface water (not desalinated)Salinas Reservoir Potable 2,385
Surface water (not desalinated)Whale Rock Reservoir Potable 2,448
Recycled Water Non-Potable 288
4,833 0
288 0
5,121 0
Submittal Table 6-8 Retail: Water Supplies — 2025 Actual
Water Code Section 10631 (b)
2025
NOTES: While the City does have a 5,482 acre-foot per year entitlement to water from Nacimiento Reservoir, the pipeline was
offline due to damage in FY 2024-25 and not used, therefore it is not represented in this table.
DWR NOTES:
Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in Submittal Table 2-3. This table
identifies the unit of measure selected in Submittal Table 2-3.
Total Entitlement: e.g. Water Right, Groundwater Allocation, Contracted Amount.
Add additional rules as needed
Total
Subtotal Potable
Subtotal Non-Potable
Drop down list
May use each category multiple
times. These are the only water
supply categories that will be
recognized by the WUEdata online
submittal tool
Additional Description
(as needed)
Water Type
(after treatment if
treated)
(OPTIONAL)
Drop Down list
Water Supply
Reasonably
Available
Volume
Total
Entitlement
(OPTIONAL)
See "DWR Notes"
below
Reasonably
Available
Volume
Total
Entitlement
(OPTIONAL)
See "DWR Notes"
below
Reasonably
Available
Volume
Total
Entitlement
(OPTIONAL)
See "DWR Notes"
below
Reasonably
Available
Volume
Total
Entitlement
(OPTIONAL)
See "DWR Notes"
below
Reasonably
Available
Volume
Total
Entitlement
(OPTIONAL)
See "DWR Notes"
below
(AF)(AF)(AF)(AF)(AF)(AF)(AF)(AF)(AF)(AF)
Purchased or Imported
Water Nacimiento Potable 5,482 5,482 5,482 5,482 5,482
Surface water (not
desalinated)
Whale Rock
and Salinas
Reservoirs
Potable 4,410 4,410 4,410 4,410 4,410
Groundwater (not Potable 700 700 700 700 700
Recycled Water Non-Potable 1,296 1,296 1,296 1,296 1,296
10,592 0 10,592 0 10,592 0 10,592 0 10,592 0
1,296 0 1,296 0 1,296 0 1,296 0 1,296 0
11,888 0 11,888 0 11,888 0 11,888 0 11,888 0
2050 (opt)
Add additional rows as needed
Total
NOTES:
2030 2035 2040 2045
Subtotal Non-Potable
Subtotal Potable
DWR NOTES:
Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in Submittal Table 2-3.
Total Entitlement: e.g. Water Right, Groundwater Allocation, Contracted Amount.
Submittal Table 6-9 Retail: Water Supplies — Projected
Water Code Section 10631 (b)
Projected Water Supply (Report to the Extent Practicable)
Drop down list
May use each category
multiple times. These are the
only water supply categories
that will be recognized by the
WUEdata online submittal
tool
Additional
Detail on
Water
Supply
Water Type
(after treatment if
treated)
(OPTIONAL)
Drop Down list
Page 373 of 476
DRAFT2025 Urban Water Management Plan
84
2030 2035 2040 2045 2050 (Opt)
(AF)(AF)(AF)(AF)(AF)
Supply totals
(autofill from Submittal
Table 6-9 R)
11,888 11,888 11,888 11,888 11,888
Use totals
(autofill from Submittal
Table 4-2 R)
7,406 7,884 8,317 8,768 9,241
Surplus/(shortfall)4,482 4,004 3,571 3,120 2,647
WSCP - supply
augmentation benefit
WSCP - use reduction
savings benefit
Revised Surplus/(shortfall)
OPTIONAL Planned WSCP Actions
Submittal Table 7-2 Retail: Normal Year Supply and Use Comparison
Water Code Section 10635 (a)
NOTES:
DWR NOTES : Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported
in Submittal Table 2-3.
2030 2035 2040 2045 2050 (Opt)
(AF)(AF)(AF)(AF)(AF)
Supply totals
(autofill from Submittal
Table 6-9 R)
10,592 10,592 10,592 10,592 10,592
Use totals
(autofill from Submittal
Table 4-2 R)
7,068 7,496 7,879 8,281 8,703
Surplus/(shortfall)3,524 3,096 2,713 2,311 1,889
WSCP - supply
augmentation benefit
WSCP - use reduction
savings benefit
Revised Surplus/(shortfall)
OPTIONAL Submittal Table 7-2 Retail: Normal Year Supply and Use Comparison -
POTABLE
OPTIONAL Planned WSCP Actions
NOTES:
Page 374 of 476
DRAFT 2025 Urban Water Management Plan
85
2030 2035 2040 2045 2050 (Opt)
(AF)(AF)(AF)(AF)(AF)
Supply totals
(autofill from Submittal
Table 6-9 R)
1,296 1,296 1,296 1,296 1,296
Use totals
(autofill from Submittal
Table 4-2 R)
338 388 438 488 538
Surplus/(shortfall)958 908 858 808 758
WSCP - supply
augmentation benefit
WSCP - use reduction
savings benefit
Revised Surplus/(shortfall)
OPTIONAL Submittal Table 7-2 Retail: Normal Year Supply and Use Comparison -
NON-POTABLE
OPTIONAL Planned WSCP Actions
NOTES:
2030 2035 2040 2045 2050 (Opt)
(AF)(AF)(AF)(AF)(AF)
Supply totals 11,488 11,488 11,488 11,488 11,488
Use totals 7,439 7,922 8,360 8,817 9,294
Surplus/(shortfall)4,049 3,566 3,128 2,671 2,194
WSCP - supply
augmentation benefit
WSCP - use reduction
savings benefit
Revised
Surplus/(shortfall)
Submittal Table 7-3 Retail: Single Dry Year Supply and Use Comparison
Water Code Section 10635(a)
OPTIONAL Planned WSCP Actions
DWR NOTES : Units of measure (AF, CCF, MG) must remain consistent throughout the
UWMP as reported in Submittal Table 2-3.
NOTES: Totals include potable and non-potable water supplies and demands.
Page 375 of 476
DRAFT2025 Urban Water Management Plan
86
2030 2035 2040 2045 2050 (Opt)
(AF)(AF)(AF)(AF)(AF)
Supply totals 10,192 10,192 10,192 10,192 10,192
Use totals 7,068 7,496 7,879 8,281 8,703
Surplus/(shortfall)3,124 2,696 2,313 1,911 1,489
WSCP - supply
augmentation benefit
WSCP - use reduction
savings benefit
Revised
Surplus/(shortfall)
OPTIONAL Submittal Table 7-3 Retail: Single Dry Year Supply and Use
Comparison - POTABLE
OPTIONAL Planned WSCP Actions
DWR NOTES : Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP
as reported in Submittal Table 2-3.
NOTES
2030 2035 2040 2045 2050 (Opt)
(AF)(AF)(AF)(AF)(AF)
Supply totals 1,296 1,296 1,296 1,296 1,296
Use totals 371 426 481 536 591
Surplus/(shortfall)925 870 815 760 705
WSCP - supply
augmentation benefit
WSCP - use reduction
savings benefit
Revised
Surplus/(shortfall)
OPTIONAL Submittal Table 7-3 Retail: Single Dry Year Supply and Use
Comparison - NON-POTABLE
OPTIONAL Planned WSCP Actions
DWR NOTES : Units of measure (AF, CCF, MG) must remain consistent throughout the
UWMP as reported in Submittal Table 2-3.
NOTES
Page 376 of 476
DRAFT 2025 Urban Water Management Plan
87
2030 2035 2040 2045 2050 (Opt)
(AF)(AF)(AF)(AF)(AF)
Supply totals 11,488 11,488 11,488 11,488 11,488
Use totals 7,439 7,922 8,360 8,817 9,294
Surplus/(shortfall)4,049 3,566 3,128 2,671 2,194
WSCP - supply
augmentation benefit
WSCP - use reduction
savings benefit
Revised
Surplus/(shortfall)
Supply totals 11,388 11,388 11,388 11,388 11,388
Use totals 7,521 8,008 8,449 8,910 9,392
Surplus/(shortfall)3,867 3,380 2,939 2,478 1,996
WSCP - supply
augmentation benefit
WSCP - use reduction
savings benefit
Revised
Surplus/(shortfall)
Supply totals 11,338 11,338 11,338 11,338 11,338
Use totals 7,603 8,095 8,540 9,005 9,491
Surplus/(shortfall)3,735 3,243 2,798 2,333 1,847
WSCP - supply
augmentation benefit
WSCP - use reduction
savings benefit
Revised
Surplus/(shortfall)
Supply totals 11,288 11,288 11,288 11,288 11,288
Use totals 7,686 8,182 8,631 9,100 9,591
Surplus/(shortfall)3,602 3,106 2,657 2,188 1,697
WSCP - supply
augmentation benefit
WSCP - use reduction
savings benefit
Revised
Surplus/(shortfall)
Supply totals 11,238 11,238 11,238 11,238 11,238
Use totals 7,770 8,271 8,723 9,197 9,691
Surplus/(shortfall)3,468 2,967 2,515 2,041 1,547
WSCP - supply
augmentation benefit
WSCP - use reduction
savings benefit
Revised
Surplus/(shortfall)
OPTIONAL WSCP Actions Second year
Third year
Fifth year
DWR NOTES: Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in Submittal
Table 2-3.
OPTIONAL Planned WSCP Actions
OPTIONAL Planned WSCP Actions
OPTIONAL Planned WSCP ActionsFourth year
NOTES:
First year
Submittal Table 7-4 Retail: Multiple Dry Years Supply and Use Comparison
Water Code Section 10635(a)
OPTIONAL Planned WSCP Actions
Page 377 of 476
DRAFT2025 Urban Water Management Plan
88
2030 2035 2040 2045 2050 (Opt)
(AF)(AF)(AF)(AF)(AF)
Supply totals 10,192 10,192 10,192 10,192 10,192
Use totals 7,068 7,496 7,879 8,281 8,703
Surplus/(shortfall)3,124 2,696 2,313 1,911 1,489
WSCP - supply augmentation
benefit
WSCP - use reduction
savings benefit
Revised Surplus/(shortfall)
Supply totals 10,092 10,092 10,092 10,092 10,092
Use totals 7,139 7,571 7,958 8,364 8,790
Surplus/(shortfall)2,953 2,521 2,134 1,728 1,302
WSCP - supply augmentation
benefit
WSCP - use reduction
savings benefit
Revised Surplus/(shortfall)
Supply totals 10,042 10,042 10,042 10,042 10,042
Use totals 7,210 7,647 8,037 8,447 8,878
Surplus/(shortfall)2,832 2,395 2,005 1,595 1,164
WSCP - supply augmentation
benefit
WSCP - use reduction
savings benefit
Revised Surplus/(shortfall)
Supply totals 9,992 9,992 9,992 9,992 9,992
Use totals 7,283 7,724 8,118 8,532 8,967
Surplus/(shortfall)2,709 2,268 1,874 1,460 1,025
WSCP - supply augmentation
benefit
WSCP - use reduction
savings benefit
Revised Surplus/(shortfall)
Supply totals 9,942 9,942 9,942 9,942 9,942
Use totals 7,355 7,801 8,199 8,617 9,056
Surplus/(shortfall)2,587 2,141 1,743 1,325 886
WSCP - supply augmentation
benefit
WSCP - use reduction
savings benefit
Revised Surplus/(shortfall)
OPTIONAL Submittal Table 7-4 Retail: Multiple Dry Years Supply and Use Comparison -
POTABLE
First year OPTIONAL Planned WSCP Actions
Second
year OPTIONAL WSCP Actions
Third
year
OPTIONAL Planned WSCP Actions
Fourth
year OPTIONAL Planned WSCP Actions
Fifth
year
OPTIONAL Planned WSCP Actions
DWR NOTES: Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in Submittal
Table 2-3.
NOTES:
Page 378 of 476
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2030 2035 2040 2045 2050 (Opt)
(AF)(AF)(AF)(AF)(AF)
Supply totals 1,296 1,296 1,296 1,296 1,296
Use totals 371 426 481 536 591
Surplus/(shortfall)925 870 815 760 705
WSCP - supply augmentation
benefit
WSCP - use reduction savings
benefit
Revised Surplus/(shortfall)
Supply totals 1,296 1,296 1,296 1,296 1,296
Use totals 382 437 492 547 602
Surplus/(shortfall)914 859 804 749 694
WSCP - supply augmentation
benefit
WSCP - use reduction savings
benefit
Revised Surplus/(shortfall)
Supply totals 1,296 1,296 1,296 1,296 1,296
Use totals 393 448 503 558 613
Surplus/(shortfall)903 848 793 738 683
WSCP - supply augmentation
benefit
WSCP - use reduction savings
benefit
Revised Surplus/(shortfall)
Supply totals 1,296 1,296 1,296 1,296 1,296
Use totals 404 459 514 569 624
Surplus/(shortfall)892 837 782 727 672
WSCP - supply augmentation
benefit
WSCP - use reduction savings
benefit
Revised Surplus/(shortfall)
Supply totals 1,296 1,296 1,296 1,296 1,296
Use totals 415 470 525 580 635
Surplus/(shortfall)881 826 771 716 661
WSCP - supply augmentation
benefit
WSCP - use reduction savings
benefit
Revised Surplus/(shortfall)
OPTIONAL Submittal Table 7-4 Retail: Multiple Dry Years Supply and Use
Comparison - NON-POTABLE
First year OPTIONAL Planned WSCP Actions
Second
year OPTIONAL WSCP Actions
DWR NOTES: Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported
in Submittal Table 2-3.
NOTES:
Third
year
OPTIONAL Planned WSCP Actions
Fourth
year OPTIONAL Planned WSCP Actions
Fifth
year
OPTIONAL Planned WSCP Actions
Page 379 of 476
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Total
Total Water Use (AF)5,661
Total Supplies (AF)7,777
2,116
WSCP - supply augmentation benefit (AF)0
WSCP - use reduction savings benefit (AF)0
2,116
Total
Total Water Use (AF)5,799
Total Supplies (AF)11,653
5,854
WSCP - supply augmentation benefit
(AF)
0
WSCP - use reduction savings benefit (AF)0
5,854
Total
Total Water Use (AF)5,864
Total Supplies (AF)11,603
5,739
WSCP - supply augmentation benefit (AF)0
WSCP - use reduction savings benefit (AF)0
5,739
Total
Total Water Use (AF)5,930
Total Supplies (AF)11,553
5,623
WSCP - supply augmentation benefit (AF)0
WSCP - use reduction savings benefit (AF)0
5,623
Total
Total Water Use (AF)5,997
Total Supplies (AF)11,503
5,506
WSCP - supply augmentation benefit (AF)0
WSCP - use reduction savings benefit (AF)0
5,506
2030
Surplus/Shortfall w/o WSCP Action
Surplus/Shortfall w/o WSCP Action
Surplus/Shortfall w/o WSCP Action
Revised Surplus/(shortfall)
Revised Surplus/(shortfall)
Surplus/Shortfall w/o WSCP Action
NOTES: The City reports UWMP data on a fiscal-year basis. For DWR Submittal
Table 7-5, reporting years 2026 through 2030 correspond to FY 2026-27 through FY
2030-31, respectively. Each fiscal year begins July 1 and ends June 30.
DWR NOTES: Units of measure (AF, CCF, MG) must remain consistent throughout
the UWMP as reported in Submittal Table 2-3.
Submittal Table 7-5 Retail: Five-Year Drought Risk Assessment
Water Code Section 10635(b)(3)
OPTIONAL Planned WSCP Actions (use reduction and supply augmentation)
OPTIONAL Planned WSCP Actions (use reduction and supply augmentation)
OPTIONAL Planned WSCP Actions (use reduction and supply augmentation)
OPTIONAL Planned WSCP Actions (use reduction and supply augmentation)
OPTIONAL Planned WSCP Actions (use reduction and supply augmentation)
Revised Surplus/(shortfall)
Surplus/Shortfall w/o WSCP Action
Revised Surplus/(shortfall)
2026
Revised Surplus/(shortfall)
2027
2028
2029
Page 380 of 476
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Total
Total Water Use (AF)5,355
Total Supplies (AF)6,481
1,126
WSCP - supply augmentation benefit (AF)0
WSCP - use reduction savings benefit (AF)0
1,126
Total
Total Water Use (AF)5,451
Total Supplies (AF)10,357
4,906
WSCP - supply augmentation benefit (AF)0
WSCP - use reduction savings benefit (AF)0
4,906
Total
Total Water Use (AF)5,506
Total Supplies (AF)10,307
4,801
WSCP - supply augmentation benefit (AF)0
WSCP - use reduction savings benefit (AF)0
4,801
Total
Total Water Use (AF)5,561
Total Supplies (AF)10,257
4,696
WSCP - supply augmentation benefit (AF)0
WSCP - use reduction savings benefit (AF)0
4,696
Total
Total Water Use (AF)5,616
Total Supplies (AF)10,207
4,591
WSCP - supply augmentation benefit (AF)0
WSCP - use reduction savings benefit (AF)0
4,591
OPTIONAL Submittal Table 7-5 Retail: Five-Year Drought Risk Assessment
- POTABLE
DWR NOTES: Units of measure (AF, CCF, MG) must remain consistent
throughout the UWMP as reported in Submittal Table 2-3.
NOTES: The City reports UWMP data on a fiscal-year basis. For DWR Submittal
Table 7-5, reporting years 2026 through 2030 correspond to FY 2026-27 through FY
2030-31, respectively. Each fiscal year begins July 1 and ends June 30.
Revised Surplus/(shortfall)
2030
Surplus/Shortfall w/o WSCP Action
OPTIONAL Planned WSCP Actions (use reduction and supply augmentation)
Revised Surplus/(shortfall)
OPTIONAL Planned WSCP Actions (use reduction and supply augmentation)
Revised Surplus/(shortfall)
2029
Surplus/Shortfall w/o WSCP Action
OPTIONAL Planned WSCP Actions (use reduction and supply augmentation)
Surplus/Shortfall w/o WSCP Action
OPTIONAL Planned WSCP Actions (use reduction and supply augmentation)
Revised Surplus/(shortfall)
2028
Surplus/Shortfall w/o WSCP Action
2026
Surplus/Shortfall w/o WSCP Action
OPTIONAL Planned WSCP Actions (use reduction and supply augmentation)
Revised Surplus/(shortfall)
2027
Page 381 of 476
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Total
Total Water Use (AF)306
Total Supplies (AF)1,296
990
WSCP - supply augmentation benefit (AF)0
WSCP - use reduction savings benefit (AF)0
990
Total
Total Water Use (AF)348
Total Supplies (AF)1,296
948
WSCP - supply augmentation benefit (AF)0
WSCP - use reduction savings benefit (AF)0
948
Total
Total Water Use (AF)359
Total Supplies (AF)1,296
937
WSCP - supply augmentation benefit (AF)0
WSCP - use reduction savings benefit (AF)0
937
Total
Total Water Use (AF)370
Total Supplies (AF)1,296
926
WSCP - supply augmentation benefit (AF)0
WSCP - use reduction savings benefit (AF)0
926
Total
Total Water Use (AF)381
Total Supplies (AF)1,296
915
WSCP - supply augmentation benefit (AF)0
WSCP - use reduction savings benefit (AF)0
915Revised Surplus/(shortfall)
DWR NOTES: Units of measure (AF, CCF, MG) must remain consistent
throughout the UWMP as reported in Submittal Table 2-3.
NOTES: The City reports UWMP data on a fiscal-year basis. For DWR
Submittal Table 7-5, reporting years 2026 through 2030 correspond to
FY 2026-27 through FY 2030-31, respectively. Each fiscal year begins July
1 and ends June 30.
OPTIONAL Submittal Table 7-5 Retail: Five-Year Drought Risk
Assessment - NON-POTABLE
OPTIONAL Planned WSCP Actions (use reduction and supply augmentation)
Revised Surplus/(shortfall)
2030
Surplus/Shortfall w/o WSCP Action
OPTIONAL Planned WSCP Actions (use reduction and supply augmentation)
2026
Surplus/Shortfall w/o WSCP Action
OPTIONAL Planned WSCP Actions (use reduction and supply augmentation)
Revised Surplus/(shortfall)
2027
Surplus/Shortfall w/o WSCP Action
OPTIONAL Planned WSCP Actions (use reduction and supply augmentation)
Revised Surplus/(shortfall)
2028
Surplus/Shortfall w/o WSCP Action
OPTIONAL Planned WSCP Actions (use reduction and supply augmentation)
Revised Surplus/(shortfall)
2029
Surplus/Shortfall w/o WSCP Action
Page 382 of 476
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Standard
Shortage
Levels
Percent
Shortage Range
Suppliers
Shortage
Levels
Percent
Shortage
Range
1 Up to 10%Watch Stage Up to 10%
2 Up to 20%Warning
Stage Up to 20%
3 Up to 30%Alert Stage Up to 30%
4 Up to 40%Severe Stage Up to 40%
5 Up to 50%Extreme
Stage Up to 50%
6 >50%Critical Stage >50%
Submittal Table 8-1: Cross-reference for Standard vs
Supplier Shortage Levels
Water Code Section 10632(a)(3)(B)
Check the box if the Supplier uses the
Standard six levels of water shortage.
Proceed to the next table.
NOTES:
Yes
Shortage Gap
Reduction Value
(May be a range)
(AF)
1 - Watch Percentage 0
2 - Warning Percentage 0
3 - Alert Percentage 0
4 - Severe Percentage 0
5 - Extreme Percentage 0
6 - Critical Percentage 0
Submittal Table 8-2 Retail: Supply Augmentation and Other Actions
Water Code Section 10632(a)(4)(A),(C) and (E)
Is the Supplier completing this table using the standard six levels? (yes/no)
Shortage
Level
Supply Augmentation Methods and
Other Actions by Water Supplier
Drop down list
These are the only categories that will
be accepted by the WUEdata online
submittal tool
How much is this going to reduce the
shortage gap? Additional
Explanation or
Reference
(OPTIONAL)
Volume or
Percentage
Drop down
Add additional rows as needed
DWR NOTES: Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in
Submittal Table 2-3. NOTES: The City of San Luis Obispo does not have any identified supply augmentation projects that have an
implementation dependent upon Water Shortage Contingency Plan Stage.
Page 383 of 476
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Yes
Shortage Gap
Reduction Value
(May be a range)
(AF)
1 Expand Public Information
Campaign Percentage 5.00%No
1 Offer Water Use Surveys Percentage 1.00%No
1 Provide Rebates on Plumbing
Fixtures and Devices Percentage 0.50%No
1 Increase Water Waste Patrols Percentage 1.00%Yes
1 Provide Rebates for Landscape
Irrigation Efficiency Percentage 0.50%No
1 Decrease Line Flushing Percentage 1.00%No
1 Reduce System Water Loss Percentage 1.00%No
2 Expand Public Information
Campaign Percentage 5.00%No
2 Increase Water Waste Patrols Percentage 3.00%Yes
2 Landscape - Limit landscape
irrigation to specific times Percentage 1.50%Yes
2 CII - Restaurants may only serve
water upon request Percentage 0.25%Yes
2
Water Features - Restrict water use
for decorative water features, such
as fountains
Percentage 0.25%Yes
3 Moratorium or Net Zero Demand
Increase on New Connections Percentage 0.25%
Initiate new
connection
offset program
Yes
3 Expand Public Information
Campaign Percentage 5.75%No
3 Increase Water Waste Patrols Percentage 3.00%Yes
3 Landscape - Limit landscape
irrigation to specific days Percentage 1.00%4 Days Per Week Yes
4 Other Percentage 8.75%
Initiate Water
Allotment
Program
Yes
4 Landscape - Limit landscape
irrigation to specific days Percentage 1.00%Three Days Per
Week Yes
4 Moratorium or Net Zero Demand
Increase on New Connections Percentage 0.25%
Intensify ratio of
new connection
offset program
Yes
5 Landscape - Limit landscape
irrigation to specific days Percentage 1.00%Two Days Per
Week Yes
5 Other Percentage 9.00%
Increase Water
Allotment
Program
Severity
Yes
6 Landscape - Prohibit all landscape
irrigation Percentage 5.00%Yes
6 Other Percentage 5.00%
Increase Water
Allotment
Program
Severity
Yes
6 Moratorium or Net Zero Demand
Increase on New Connections Percentage 0.00%Yes
Submittal Table 8-3 Retail: Demand Reduction Actions
Water Code Section 10632(a)(4)(B) and (E)
Is the Supplier completing this table using the standard six levels? (yes/no)
Shortage
Level
Demand Reduction Actions
Drop down list
These are the only categories that will
be accepted by the WUEdata online
submittal tool. Select those that apply.
How much is this going to
reduce the shortage gap? Additional
Explanation or
Reference
(OPTIONAL)
Penalty,
Charge, or
Other
Enforcement?
For Retail Suppliers
Only
Drop Down List
Volume or
Percentage
Drop down
Add additional rows as needed
DWR NOTES: Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in
Submittal Table 2-3.
NOTES:
1. During Stage 6, Cessation of New Connections is represented as resulting in a 0% decrease in water demand, as
this cessation will not reduce current water use, rather it aims to reduce future water demand attributed to new
development.
2. Demand reduction actions are intended to be cumulative. Actions implemented at a lower shortage level are
assumed to remain in effect at higher shortage levels unless modified, suspended, or replaced by City Council
action.
Page 384 of 476
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City Name 60 Day Notice
Drop Down (yes/no)
Notice of Public
Hearing
Drop Down (yes/no)
County Name
Drop Down List
60 Day Notice
Drop Down (yes/no)
Notice of Public
Hearing
Drop Down (yes/no)
San Luis Obispo
County Yes Yes
Submittal Table 10-1 Retail: Notification to Cities and
Counties
Water Code Section 10621(b) and 10642
Add additional rows as needed
Add additional rows as needed
NOTES: Verbal notice provided to County staff prior to 60-day
deadline. Formal written notice provided 5/9/2026.
Page 385 of 476
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Appendix B – DWR UWMP Compliance Checklist
Retail
(x =
required)
Wholesale
(x = required)
2025
Guidebook
Location
Water Code
Section Summary as Applies to UWMP Subject
Relevant
Submittal
Table
2025
UWMP
Location
x x Chapter 1 10615
A plan shall describe and evaluate sources of supply, reasonable and
practical efficient uses,
reclamation and demand management activities.
Introduction and
overview n/a
Executive Summary, pp. 8-9; Ch. 1,
pp. 10-13; Ch. 4, pp. 23-28; Ch. 6, pp.
31-53; Ch. 9, pp. 63-70.
x x Chapter 1 10630.5
Each plan shall include a simple description of the Supplier’s plan
including water availability,
future requirements, a strategy for meeting needs, and other pertinent
information.
Additionally, a Supplier may also choose to include a simple description
at the beginning of each
chapter.Plan preparation n/a
Executive Summary and Lay
Description, pp. 8-9; Ch. 1, pp. 10-13.
x x Section 2.1 10620(b)
Every person that becomes a Supplier shall adopt UWMP within one year
after it has become a
Supplier.Plan preparation n/a
Not applicable — City is an existing
urban water supplier.
x n/a Section 2.5 10644
Supplier shall report the Public Water Systems number, volume of
delivered water, and number
of connections that are included in this UWMP.Plan preparation 2-1
Appendix A; DWR Submittal Table 2-
1.
x x Section 2.5 10644
Supplier shall report if this UWMP is an individual UWMP and whether the
Supplier belongs to a
regional UWMP or regional alliance.Plan preparation 2-2
Appendix A; DWR Submittal Table 2-
2.
x x Section 2.5 10644
Supplier shall report whether the data is in fiscal or calendar years and
the units of measure
used for reporting water volumes.Plan preparation 2-3
Section 2.3, p. 14; Appendix A; DWR
Submittal Table 2-3.
x x Section 2.4 10642
Provide supporting documentation that the Supplier has encouraged
active involvement of
diverse social, cultural, and economic elements of the population within
the service area prior to
and during the preparation of the plan and contingency plan.Plan preparation n/a
Sections 2.2, p. 14; 10.2-10.4, pp. 71;
Appendix C.
x x Section 2.4.2 10620(d)(3)
Coordinate the preparation of its plan with other appropriate agencies in
the area, including
other Suppliers that share a common source, water management Plan preparation n/a
Section 2.1, pp. 13-14; Section 10.2,
p. 71; Appendix C.
x n/a Section 2.4.1 10631(h)
Retail Suppliers will include documentation that they have provided their
Wholesale
Supplier(s)—if any—with water use projections from that source.Plan preparation 2-4 R Section 2.1, pp. 13-14, Appendix C.
n/a x Section 2.4.1 10631(h)
Wholesale Suppliers will provide their Suppliers with identification and
quantification of the
existing and planned sources of water available from the Wholesale
Supplier to the Supplier
during various water year types.Plan preparation 2-4 W
Not applicable — City is a retail
supplier, not a wholesale supplier.
x x Chapter 3.0 10631(a)Describe the Supplier service area.System description n/a Sections 3.1-3.2, pp. 15-16.
x x Section 3.3 10631(a)Describe the climate of the Supplier’s service area.System description n/a
Section 3.3, pp. 16-17; Table 3-1, p.
16.
x x Section 3.4.1 10631(a)
Provide the current and projected service area populations for 2030,
2035, 2040, 2045 and
optionally 2050.System description 3-1
Sections 3.5-3.6, pp. 20-22; Table 3-3,
p. 22; Appendix A; DWR Submittal
Table 3-1.
x x Section 3.4.2 10631(a)
Describe other social, economic, and demographic factors affecting the
Supplier’s water System description n/a
Section 3.5, pp. 20-21; Table 3-2, p.
21.
x x Section 3.5 10631(a)
Describe the land uses within the service area… include the current and
projected land uses
within the existing or anticipated service area affecting the Supplier’s
System description
and baselines n/a Section 3.7, pp. 22-23.
x Optional
Sections 4.2.3
and
4.2.4 10631(d)(1)
Quantify past, current, and projected water use, identifying the uses
among water use sectors.System water use 4-1 and 4-2
Sections 4.1-4.5, pp. 23-27; Tables 4-
1 through 4-3, pp. 25, 27; Appendix A;
DWR Tables 4-1 and 4-2.
x Optional Section 4.3.1
10631(d)(3)(
A)
Report the distribution system water loss for each of the five years
preceding the plan update.System water use 4-5
Section 4.6, pp. 28-29; Table 4-5, p.
29; Appendix D, p. 77; Appendix A;
DWR Table 4-5.
x n/a Section 4.3.2
10631(d)(3)(
C)
Retail Suppliers shall provide data to show the distribution loss standards
were met.System water use 4-6
Section 4.6, pp. 28-29; Table 4-5, p.
29; Appendix D, p. 77; Appendix A;
DWR Table 4-6.
x n/a Section 4.2.5.4 10631.1(a)
Include projected water use needed for lower income housing projected
in the service area of
the Supplier.System water use 4-3
Section 4.5, pp. 26-27; Table 4-2, p.
27; Appendix A; DWR Table 4-3.
x n/a Section 4.2.5.3
10631(d)(4)(
A)
In projected water use, include estimates of water savings from adopted
codes, plans, and
other policies or laws.System water use 4-3
Section 3.7, p. 23; Section 4.5, p. 26;
Section 9.11.4, p. 69; Appendix A;
DWR Table 4-3.
x n/a Section 4.2.5.3
10631(d)(4)(
B)
Provide citations of codes, standards, ordinances, or plans used to make
water use projections.System water use 4-3
Section 3.7, p. 23; Section 4.5, p. 26;
Section 9.11.4, p. 69; Appendix A, p.
74; DWR Table 4-3.
x n/a Section 4.2.5.3
10631(d)(4)(
B)(ii)
To the extent that a Supplier reports the information described in
subparagraph (A), an urban
water Supplier shall… Indicate the extent that the water use projections
consider savings from
codes, standards, ordinances, or transportation and land use plans.
Water use projections that
do not account for these water savings shall be noted of that fact.System water use 4-3
Section 4.5, p. 26; Appendix A; DWR
Table 4-3.
x x Section 4.2.5.6 10635(b)
Demands under climate change considerations must be included as part
of the drought risk
assessment.System water use n/a
Section 6.6, pp. 52-53; Section 7.7,
pp. 58-60.
n/a x Section 5.1 10608.36
Wholesale Suppliers shall include an assessment of present and
proposed future measures,
programs, and policies to help their Retail Suppliers achieve targeted
water use reductions.
Baselines and
targets n/a
Not applicable — City is a retail
supplier, not a wholesale supplier.
Page 386 of 476
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Retail
(x =
required)
Wholesale
(x = required)
2025
Guidebook
Location
Water Code
Section Summary as Applies to UWMP Subject
Relevant
Submittal
Table
2025
UWMP
Location
x n/a Section 5.2 10608.40
Retail Suppliers shall report on their compliance in meeting their water
use targets. Reporting
requirements will vary depending on whether the Supplier:
- Was considered an urban retail water supplier in 2020,
- Met its 2020 target in 2020, or
- Was part of a merger or consolidation since 2020.
Chapter 5 Subsections 5.2.1, 5.2.2, and 5.2.3 address each of these
situations.
Baselines and
targets 5-1
Sections 5.1-5.3, pp. 30-31; Table 5-1,
p. 30; Appendix A; DWR Table 5-1.
x x Section 6.1 10631(b)(2)
When multiple sources of water supply are identified, describe the
management of each supply
in relationship to other identified supplies.System supplies n/a
Sections 3.4.1, p. 17; 6.2, pp. 32-42;
6.3.1, pp. 42-43; 6.4.2-6.4.3, pp. 49-
50.
x x
Sections 6.1
and
6.2 10631(b)(1)
Provide a discussion of anticipated supply availability under a normal,
single dry year, and a
drought lasting five years, as well as more frequent and severe periods of
drought, including
changes in supply due to climate change.System supplies n/a
Sections 6.1-6.7, pp. 31-53; Ch. 7, pp.
53-60; Section 7.7, pp. 58-60; Section
6.6, pp. 52-53.
x x Section 6.2.2
10631(b)(4)(
C)
Indicate whether groundwater is an existing or planned source of water
available to the
Supplier. If groundwater is identified as an existing or planned source of
water… (include) a
detailed description and analysis of the location, amount and sufficiency
of groundwater
pumped by the Supplier for the past five years.
Water supplies and
recycled water 6-1
Section 6.2.4, pp. 38-39; Section
6.3.4, pp. 46-47; Table 6-3, p. 39;
Appendix A; DWR Table 6-1.
x x Section 6.2.2
10631(b)(4)(
A)
Indicate whether a groundwater sustainability plan or groundwater
management plan has been
adopted by the Supplier or if there is any other specific authorization for
groundwater
management. Include a copy of the plan or authorization.System supplies n/a
Section 6.2.4, pp. 38-39; Section
6.3.4, pp. 46-47.
x x Section 6.2.2
10631(b)(4)(
B)Describe the groundwater basin.System supplies n/a
Section 6.2.4, pp. 38-39; Section
6.3.4, pp. 46-47.
x x Section 6.2.2
10631(b)(4)(
B)
Indicate if the basin has been adjudicated and include a copy of the court
order or decree and a
description of the amount of water the Supplier has the legal right to
pump.System supplies n/a
Section 6.2.4, pp. 38-39; Section
6.3.4, pp. 46-47.
x x Section 6.2.2
10631(b)(4)(
B)
For unadjudicated basins… (include) information as to whether DWR has
identified the basin as
a high- or medium-priority basin in the most current official departmental
bulletin…
Water supplies and
recycled water n/a
Section 6.2.4, pp. 38-39; Section
6.3.4, pp. 46-47.
x x Section 6.2.2
10631(b)(4)(
B)
For unadjudicated basins… describe efforts by the Supplier to coordinate
with sustainability or
groundwater agencies to achieve sustainable groundwater conditions.
Water supplies and
recycled water n/a
Section 6.2.4, pp. 38-39; Section
6.3.4, pp. 46-47.
x x Section 6.2.2.
10631(b)(4)(
C)
If groundwater is identified as an existing or planned source of water…
(include) a detailed
description and analysis of the location, amount and sufficiency of System supplies n/a
Section 6.2.4, pp. 38-39; Table 6-3, p.
39.
x x Section 6.2.2
10631(b)(4)(
D)
Provide a detailed description and analysis of the amount and location of
groundwater that is
projected to be pumped.System supplies 6-9
Section 6.2.4, pp. 38-39; Section
6.3.4, pp. 46-47; Table 6-7, p. 49;
Appendix A; DWR Table 6-9.
x x Section 6.1 10631(b)
Identify and quantify the existing and planned sources of water available
for 2025, 2030, 2035,
2040, 2045 and optionally 2050.System supplies 6-8 and 6-9
Sections 6.2-6.4.3, pp. 32-50; Tables
6-6 through 6-8, pp. 48-50; Appendix
A; DWR Tables 6-8 and 6-9.
x x Section 6.2.7 10631(c)
Describe the opportunities for exchanges or transfers of water on a short-
term or long-term System supplies n/a Section 6.7, p. 53.
x n/a Section 6.2.5 10633(a)
Describe the wastewater collection and treatment systems in the
Supplier’s service area with
quantified amount of collection and treatment and the disposal methods.
System supplies
(recycled water)6-2
Section 3.4.4, p. 20; Section 6.2.5, pp.
40-42; Table 6-4, p. 41; Appendix A;
DWR Table 6-2.
x x Section 6.2.5 10633(b)
Describe the quantity of treated wastewater that meets recycled water
standards, is being
discharged, and is otherwise available for use in a recycled water project.
System supplies
(recycled water)6-3
Section 3.4.4, p. 20; Section 6.2.5, pp.
40-42; Table 6-4, p. 41; Appendix A;
DWR Table 6-3.
x x Section 6.2.5 10633(c)
Describe the recycled water currently being used in the Supplier's service
area.
System supplies
(recycled water)6-4
Section 3.4.4, p. 20; Section 6.2.5, pp.
40-42; Table 6-5, p. 41; Appendix A;
DWR Table 6-4.
x x Section 6.2.5 10633(d)
Describe and quantify the potential uses of recycled water and provide a
determination of the
technical and economic feasibility of those uses.
System supplies
(recycled water)6-4
Section 6.2.5, pp. 40-42; Section
6.3.5, p. 47; Appendix A, p. 74; DWR
Table 6-4
x x Section 6.2.5 10633(e)
Describe the projected use of recycled water within the Supplier's service
area at the end of 5,
10, 15, and 20 years, and describe the actual use of recycled water in
comparison to uses
previously projected.
System supplies
(recycled water)6-4 and 6-5
Section 6.2.5, pp. 40-42; Section
6.3.5, p. 47; Table 6-8, p. 50; Appendix
A; DWR Tables 6-4 and 6-5.
x x Section 6.2.5 10633(f)
Describe the actions that may be taken to encourage the use of recycled
water and the
projected results of these actions in terms of acre-feet of recycled water
used per year.
System supplies
(recycled water)6-6
Section 6.2.5, pp. 40-42; Section
6.3.5, p. 47; Section 6.5, pp. 51-52;
Appendix A; DWR Table 6-6.
x x Section 6.2.5 10633(g)
Provide a plan for optimizing the use of recycled water in the Supplier's
service area.
System supplies
(recycled water)n/a
Section 6.2.5, pp. 40-42; Section
6.3.5, p. 47; Section 6.5, pp. 51-52;
Section 9.11.1, p. 68.
x x Section 6.2.6 10631(g)Describe desalinated water project opportunities for long-term supply.System supplies 6-7
Section 6.5, pp. 51-52; Appendix A;
DWR Table 6-7.
x x Section 6.2.10 10631(f)
Describe the expected future water supply projects and programs that
may be undertaken by
the water Supplier to address water supply reliability in average, single-
dry, and for a period of
drought lasting five consecutive water years.System supplies 6-7
Section 6.5, pp. 51-52; Sections 6.3.3-
6.3.5, pp. 45-47; Appendix A; DWR
Table 6-7.
x x
Section 6.3 and
Appendix O 10631.2(a)
The UWMP must include energy information, as stated in the code, that a
Supplier can readily
obtain.
System suppliers,
energy intensity
O-1A, O-1B,
O-1C, and O-
2
Section 6.4.4, pp. 50-51; Table 6-9, p.
51.
x Section 7.1 10634
Provide information on the quality of existing sources of water available to
the Supplier and the
manner in which water quality affects water management strategies and
supply reliability.
Water supply
reliability
assessment n/a
Sections 3.4.2, pp. 18-19; 6.6, pp. 52-
53; 7.2, p. 54; 7.7, pp. 58-60; 8.2, p.
61.
x x Section 7.2 10635(a)
Service Reliability Assessment: Assess the water supply reliability during
normal, dry, and a
drought lasting five consecutive water years by comparing the total water
supply sources
available to the Supplier with the total projected water use over the next
20 years.
Water supply
reliability
assessment
7-2, 7-3, and
7-4
Sections 7.1-7.6, pp. 53-58; Tables 7-
1 through 7-6, pp. 56-58; Appendix A;
DWR Tables 7-2, 7-3, and 7-4.
Page 387 of 476
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98
Retail
(x =
required)
Wholesale
(x = required)
2025
Guidebook
Location
Water Code
Section Summary as Applies to UWMP Subject
Relevant
Submittal
Table
2025
UWMP
Location
x x Section 7.2.3 10620(f)
Describe water management tools and options to maximize resources
and minimize the need to
Water supply
reliability n/a
Sections 6.3.1, pp. 42-43; 6.5, pp. 51-
52; 7.2, p. 54; 9.13, p. 70.
x x Section 7.3 10635(b)
Provide a drought risk assessment as part of information considered in
developing the demand
Water supply
reliability n/a
Section 7.7, pp. 58-60; Tables 7-7 and
7-8, pp. 59-60.
x x Section 7.3 10635(b)(1)
Include a description of the data, methodology, and basis for one or more
supply shortage
conditions that are necessary to conduct a drought risk assessment for a
Water supply
reliability
assessment n/a
Section 7.7, pp. 58-60; Tables 7-7 and
7-8, pp. 59-60.
x x Section 7.3 10635(b)(2)
Include a determination of the reliability of each source of supply under a
variety of water
Water supply
reliability n/a
Sections 6.3.2-6.3.5, pp. 43-47;
Section 7.7, pp. 58-60; Tables 7-7 and
x x Section 7.3 10635(b)(3)
Include a comparison of the total water supply sources available to the
Supplier with the total
Water supply
reliability 7-5
Section 7.7, pp. 58-60; Tables 7-7 and
7-8, pp. 59-60; Appendix A, p. 74;
x x Section 7.3 10635(b)(4)
Include considerations of the historical drought hydrology, plausible
changes on projected
supplies and demands under climate change conditions, anticipated
Water supply
reliability
assessment n/a
Sections 6.6, pp. 52-53; 7.7, pp. 58-
60.
x x Chapter 8 10632(a)
Provide a water shortage contingency plan (WSCP) with specified
elements below.
Water shortage
contingency n/a Chapter 8, pp. 60-63; Appendix H.
x x Chapter 8 10632(a)(1)
Provide an analysis of water supply reliability (from Guidebook Chapter 7)
in the WSCP.
Water shortage
contingency
planning n/a Section 7.2, pp. 54.
x x Section 8.2
10632(a)(2)(
A)
Provide the written decision-making process and other methods that the
Supplier will use each
year to determine its water reliability.
Water shortage
contingency
planning n/a Section 7.2, pp. 54.
x x Section 8.2
10632(a)(2)(
B)
Provide data and methodology to evaluate the Supplier’s water reliability
for the current year
and one dry year pursuant to factors in the code.
Water shortage
contingency
planning n/a
Section 7.2, pp. 54, Section 7-7 pp. 58-
60.
x x Section 8.3
10632(a)(3)(
A)
Define six standard water shortage levels of 10%, 20%, 30%, 40%, 50%
shortage, and greater
than 50% shortage. These levels shall be based on supply conditions,
including percent
reductions in supply, changes in groundwater levels, changes in surface
elevation, or other
conditions. The shortage levels shall also apply to a catastrophic
interruption of supply.
Water shortage
contingency
planning n/a
Section 8.3, pp. 62-63; Appendix A;
DWR Table 8-1; Appendix H.
x x Section 8.3
10632(a)(3)(
B)
Suppliers with an existing WSCP that uses different water shortage
levels must cross reference
their categories with the six standard categories.
Water shortage
contingency
planning 8-1
Section 8.3, pp. 62-63; Appendix A;
DWR Table 8-1; Appendix H.
x x Section 8.4
10632(a)(4)(
A)
Suppliers with WSCPs that align with the defined shortage levels must
specify locally
appropriate supply augmentation actions.
Water shortage
contingency
planning 8-2
Appendix A; DWR Table 8-2; Appendix
H.
x x Section 8.4
10632(a)(4)(
B)
Specify locally appropriate demand reduction actions to adequately
respond to shortages.
Water shortage
contingency
planning 8-3
Appendix A; DWR Table 8-3; Appendix
H.
x x Section 8.4
10632(a)(4)(
C)Specify locally appropriate operational changes.
Water shortage
contingency
planning 8-2
Appendix A, p. 74; DWR Table 8-2;
Appendix H.
x x Section 8.4
10632(a)(4)(
D)
Specify additional mandatory prohibitions against specific water use
practices that are in
addition to State-mandated prohibitions are appropriate to local
conditions.
Water shortage
contingency
planning Table 8-3 Appendix H.
x x Section 8.4
10632(a)(4)(
E)
Estimate the extent to which the gap between supplies and demand will
be reduced by
implementation of the action.
Water shortage
contingency
planning 8-2 and 8-3
Appendix A, p. 74; DWR Tables 8-2
and 8-3; Appendix H.
x x Section 8.4.6 10632.5 The UWMP shall include a seismic risk assessment and mitigation plan.
Water shortage
contingency plan n/a
Section 8.2.1, pp. 61-62; Appendix G,
p. 80.
x x Section 8.5
10632(a)(5)(
A)
Suppliers must describe that they will inform customers, the public and
others regarding any
current or predicted water shortages.
Water shortage
contingency
planning n/a Appendix H
x x Section 8.5
10632(a)(5)(
B),
10632(a)(5)(
C)
Suppliers must describe that they will inform customers, the public and
others regarding any
shortage response actions triggered or anticipated to be triggered and
other relevant
communications.
Water shortage
contingency
planning n/a Appendix H
x n/a Section 8.6 10632(a)(6)
Retail Supplier must describe how it will ensure compliance with and
enforce provisions of the
WSCP.
Water shortage
contingency
planning n/a Appendix H
x x Section 8.7
10632(a)(7)(
A)
Describe the legal authority that empowers the Supplier to enforce
shortage response actions.
Water shortage
contingency
planning n/a Appendix H
x x Section 8.7
10632(a)(7)(
B)
Provide a statement that the Supplier will declare a water shortage
emergency per Water Code
Chapter 3. Water Shortage Emergencies.
Water shortage
contingency
planning n/a Appendix H
x x Section 8.7
10632(a)(7)(
C)
Provide a statement that the Supplier will coordinate with any city or
county within which it
provides water for the possible proclamation of a local emergency.
Water shortage
contingency
planning n/a Appendix H
x x Section 8.8
10632(a)(8)(
A)
Describe the potential revenue reductions and expense increases
associated with activated
shortage response actions.
Water shortage
contingency
planning n/a Appendix H
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Retail
(x =
required)
Wholesale
(x = required)
2025
Guidebook
Location
Water Code
Section Summary as Applies to UWMP Subject
Relevant
Submittal
Table
2025
UWMP
Location
x x Section 8.8
10632(a)(8)(
B)
Provide a description of mitigation actions needed to address revenue
reductions and expense
increases associated with activated shortage response actions.
Water shortage
contingency
planning n/a Appendix H
x n/a Section 8.8
10632(a)(8)(
C)
Retail Suppliers must describe the cost of compliance with Water Code
Chapter 3.3, Excessive
Residential Water Use During Drought.
Water shortage
contingency
planning n/a Appendix H
x n/a Section 8.9 10632(a)(9)
Retail Suppliers must describe the monitoring and reporting requirements
and procedures that
ensure appropriate data are collected, tracked, and analyzed for
purposes of monitoring
customer compliance.
Water shortage
contingency
planning n/a Appendix H
x x Section 8.10 10632(a)(10)
Describe reevaluation and improvement procedures for monitoring and
evaluation the WSCP to
ensure risk tolerance is adequate and appropriate water shortage
mitigation strategies are
implemented.
Water shortage
contingency
planning n/a Appendix H
x n/a Section 8.11 10632(b)
Analyze and define water features that are artificially supplied with water,
including ponds,
lakes, waterfalls, and fountains, separately from swimming pools and
spas.
Water shortage
contingency
planning n/a Appendix H
x x Section 8.12 10632(c)
Make available the WSCP to customers and any city or county where it
provides water within 30
days after adoption of the plan.
Water shortage
contingency
planning n/a
Sections 8.4, p. 63; 10.5-10.6, pp. 71-
72; Appendix H.
x n/a Sections 9.1 10631(e)(1)
Retail Suppliers shall provide a description of the nature and extent of
each demand
management measure implemented over the past five years. The
description will address
specific measures listed in code.
Demand
management
measures n/a Chapter 9, pp. 63-70; Table 9-1, p. 65.
n/a x Sections 9.2 10631(e)(2)
Wholesale Suppliers shall describe specific demand management
measures listed in code, their
distribution system asset management program, and Supplier assistance
program.
Demand
management
measures n/a
Not applicable — City is a retail
supplier, not a wholesale supplier.
x n/a Chapter 10 10608.26(a)
Retail Suppliers shall conduct a public hearing to discuss adoption,
implementation, and
economic impact of water use targets (recommended to discuss
compliance).
Plan adoption,
submittal, and
implementation n/a Chapter 10, pp. 70-73; Appendix C.
x x Section 10.2.1 10621(b)
Notify, at least 60 days prior to the public hearing, any city or county within
which the Supplier
provides water that the Supplier will be reviewing the UWMP and
considering amendments or
changes to the plan.
Plan adoption,
submittal, and
implementation 10-1
Sections 10.2 and 10.5, pp. 71-72;
Table 10-1, p. 72; Appendix C.
x x Section 10.4 10621(f)
Each urban water Supplier shall update and submit its 2025 plan to DWR
by July 1, 2026.
Plan adoption,
submittal, and
implementation n/a
Section 10.5, pp. 71-72; Table 10-1, p.
72; Appendix C.
x x
Sections 10.2.2,
10.3, and 10.5 10642
Provide supporting documentation that the Supplier made the UWMP and
WSCP available for
public inspection, published notice of the public hearing, and held a public
hearing about the
UWMP and WSCP.
Plan adoption,
submittal, and
implementation n/a
Sections 10.3-10.5, pp. 71-72;
Appendix C.
x x Section 10.2.2 10642
The Supplier is to provide the time and place of the hearing to any city or
county within which
the Supplier provides water.
Plan adoption,
submittal, and
implementation 10-1
Section 10.2, p. 71; Table 10-1, p. 72;
Appendix C.
x x Section 10.3.2 10642
Provide supporting documentation that the UWMP and WSCP has been
adopted as prepared or
modified.
Plan adoption,
submittal, and
implementation n/a Section 10.4, p. 71; Appendix C.
x x Section 10.4 10644(a)
Provide supporting documentation that the Supplier has submitted their
UWMP to the California
State Library.
Plan adoption,
submittal, and
implementation n/a
Section 10.5, pp. 71-72; Table 10-1, p.
72; Appendix C.
x x Section 10.4 10644(a)(1)
Provide supporting documentation that the Supplier has submitted their
UWMP to any city or
county within which the Supplier provides water no later than 30 days
after adoption.
Plan adoption,
submittal, and
implementation n/a
UWMP Table 10-1, pp. 72. Appendix
C.
x x
Sections 10.4.1
and
10.4.2 10644(a)(2)
The UWMP, or amendments to the UWMP, submitted to DWR shall be
submitted electronically.
Plan adoption,
submittal, and
implementation n/a
Section 2.4, p. 15; Sections 10.5 and
10.8, pp. 71-73; Table 10-1, p. 72.
x x Section 10.7.2 10644(b)
If revised, submit a copy of the WSCP to DWR within 30 days of
adoption.
Plan adoption,
submittal, and
implementation n/a Section 10.8, p. 73; Appendix H.
x x Section 10.5 10645(a)
Provide supporting documentation that, not later than 30 days after filing a
copy of its UWMP
with DWR, the Supplier has or will make the plan available for public
review during normal
business hours.
Plan adoption,
submittal, and
implementation n/a
Sections 10.6-10.7, pp. 72-73; Table
10-1, p. 72.
x x Section 10.5 10645(b)
Provide supporting documentation that, not later than 30 days after filing a
copy of its WSCP
with DWR, the Supplier has or will make the plan available for public
review during normal
business hours.
Plan adoption,
submittal, and
implementation n/a
Sections 8.4, p. 63; 10.6-10.7, pp. 72-
73; Table 10-1, p. 72.
x x Section 10.6 10621(c)
If Supplier is regulated by the Public Utilities Commission, include its plan
and contingency plan
as part of its general rate case filings.
Plan adoption,
submittal, and
implementation n/a
Not applicable — City is not regulated
by the California Public Utilities
Commission.
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Appendix C – Public Notices, Agency Coordination, and Adoption Documentation
This appendix will be updated with appropriate notices when the final report is compiled.
Page 390 of 476
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Page 391 of 476
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102
RESOLUTION NO. _____ (2026 SERIES)
A RESOLUTION OF THE CITY COUNCIL OF THE CITY OF SAN LUIS
OBISPO, CALIFORNIA, ADOPTING THE 2025 URBAN WATER
MANAGEMENT PLAN
WHEREAS, the California Legislature enacted Assembly Bill 797 during the 1983-1984 Regular
Session, and as amended subsequently, which mandates that every supplier providing water for municipal
purposes to more than 3,000 customers or supplying more than 3,000 acre-feet of water annually, prepare
an Urban Water Management Plan; and
WHEREAS, the City is an urban water supplier providing more than 3,000 acre-feet water annually
to approximately 17,000 customers; and
WHEREAS, the City’s Urban Water Management Plan shall be periodically reviewed at least once
every five years, and that the City shall make any amendments or changes to its plan which are indicated
by the review; and
WHEREAS,the 2025 Urban Water Management Plan must be adopted, after public review and
hearing, and filed with the California Department of Water Resources by July 1, 2026;and
WHEREAS, the City has therefore prepared for public review a draft 2025 Urban Water
Management Plan, and a properly noticed public hearing regarding the Plan was held by the City Council
on June 16, 2026.
NOW, THEREFORE, BE IT RESOLVED by the Council of the City of San Luis Obispo as follows:
SECTION 1. Adoption of the 2025 Urban Water Management Plan. The 2025 Urban Water
Management Plan for the City of San Luis Obispo, consisting of text, tables, and appendices presented to
the City Council on June 16, 2026, on file at the City Clerk’s Office, is hereby adopted.
SECTION 2.The Public Works and Utilities Director or Assistant Utilities Director are hereby
directed to distribute the 2025 Urban Water Management Plan to the California Department of Water
Resources, the California State Library, and the County of San Luis Obispo,and make available for public
review as prescribed by state law.
SECTION 3. California Environmental Quality Act. The adoption of the City’s 2025 Urban Water
Management Plan is hereby determined to be statutorily exempt from the requirements of the California
Environmental Quality Act (CEQA) pursuant to State CEQA Guidelines Section 15282(v), the preparation
of Urban Water Management Plans pursuant to the provisions of Section 10652 of the Water Code.
Upon motion of Council Member ___________, seconded by Council Member ___________, and
on the following roll call vote:
AYES:
NOES:
ABSENT:
Page 392 of 476
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103
The foregoing resolution was adopted this _____ day of _______________ 20 26.
___________________________
Mayor Erica A. Stewart
ATTEST:
______________________
Teresa Purrington
City Clerk
APPROVED AS TO FORM:
______________________
J. Christine Dietrick
City Attorney
IN WITNESS WHEREOF, I have hereunto set my hand and affixed the official seal of the City of San Luis
Obispo, California, on ______________________.
___________________________
Teresa Purrington
City Clerk
Page 393 of 476
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Appendix D – Water Loss Audit Documentation
The City prepares annual validated water loss audit reports in accordance with State reporting requirements
and submits those reports to the California Department of Water Resources through the State’s Water Use
Efficiency data reporting system. Water loss audits are used to evaluate water supplied, authorized
consumption, apparent losses, real losses, and related water loss performance indicators for the City’s
potable water distribution system.
Rather than reproducing each full water loss audit report in this appendix, the City provides direct links to
the submitted audit files available through the State’s Water Use Efficiency reporting portal. This approach
avoids duplicating lengthy documents that are already maintained through the State’s reporting system
while still providing access to the supporting audit records used in this UWMP. The City also maintains
copies of the submitted audit files in its administrative records.
2025 UWMP Water Loss Audit Documentation
Reporting Year Reporting Year Basis Report Link
2025 Fiscal Year FY 2024-25 Water Loss Audit
2024 Fiscal Year FY 2023-24 Water Loss Audit
2023 Fiscal Year FY 2022-23 Water Loss Audit
2022 Calendar Year CY 2022 Water Loss Audit
2021 Calendar Year CY 2021 Water Loss Audit
2020 Calendar Year CY 2020 Water Loss Audit
Notes:
1. Water loss audit reports are available through the State’s Water Use Efficiency data reporting system.
2. The City transitioned from calendar-year water loss audit reporting to fiscal-year reporting following the
Calendar Year 2022 audit.
3. If a direct portal link changes, the audit may be accessed by searching for the City of San Luis Obispo in
the State’s water loss audit reporting portal at https://wuedata.water.ca.gov/awwa_plans.
Page 394 of 476
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Appendix E – Safe Annual Yield Technical Memorandum
This appendix will be added when final report is compiled.
Page 395 of 476
DRAFTTechnical Memorandum
City SAY Model Update TM
Date: 1/8/2018
To: Mr. Aaron Floyd
City of San Luis Obispo – Public Utilities
San Luis Obispo, California
Prepared by: Adam Rianda, P.E.
Reviewed by: Jeroen Olthof, P.E.
Project: Safe Annual Yield Analysis Update
SUBJECT: SALINAS AND WHALE ROCK RESERVOIRS SAFE ANNUAL YIELD
Section 1: Background
The City of San Luis Obispo (City) maintains a diversified portfolio of water supply sources that it can use to meet
potable water demand. Two of these sources are Salinas Reservoir, also known as Santa Margarita Lake, and
Whale Rock Reservoir, located near the town of Cayucos. Whale Rock Reservoir is a shared‐use reservoir serving
the City, the California Polytechnic State University (Cal Poly), the California Men’s Colony (CMC), and the town
of Cayucos. The City, Cal Poly, and CMC comprise the Whale Rock Commission, which governs reservoir
operation. Some characteristics of the two reservoirs are shown in Table 1.
Table 1. Reservoir Attributes
Reservoir Watershed Size
(Square Miles)
Storage Capacity
(Acre Feet)
Average Annual
Precipitation
(Inches)1
Average Annual
Evaporation
(Inches)1
Salinas 112.0 23,843 22.1 85.4
Whale Rock 20.3 38,967 18.7 61.6
1Average annual precipitation and evaporation depths are based on the verified hydrologic data discussed in Section 2.
Salinas Reservoir and Whale Rock Reservoir are located in different climate regions and have differing
characteristics. Whale Rock Reservoir has a larger storage volume than Salinas, but it has a smaller watershed to
provide natural recharge. Salinas Reservoir receives more runoff each year, but it also experiences higher
temperatures and higher evaporation rates, and it spills more frequently. To maximize the available supply from
these two reservoirs, the City has developed operational strategies that recognize the differences between the
reservoirs. In general, the strategies involve withdrawing water from Salinas Reservoir when it is available, and
using Whale Rock Reservoir as‐needed to supplement the supply from Salinas.
To assist with the management of the City’s water resources and understand the available supply from Salinas
and Whale Rock Reservoirs, the City maintains an Excel‐based model that estimates a safe annual yield (SAY)
based on historical climatic conditions and reservoir operations. For each reservoir, the model sums the inputs
and outputs to calculate the reservoir volume on a monthly time step. As inputs, the model uses the historical
106
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City SAY Model Update TM
record of inflows, evaporation, precipitation, and downstream releases. The model then calculates, over the
period of record, the maximum amount that could be withdrawn each year without drawing the reservoir below
its minimum pool constraint. This maximum allowable annual withdrawal is considered to be the SAY.
The City’s Excel‐based model of the two reservoirs was first developed in 1988. At that time, the critical drought
period that controlled the SAY was the 1946‐1951 drought. In 1991 the model was updated to incorporate the
hydrologic conditions experienced during the 1986‐1991 drought. That drought was the most severe in the
historical record to that point and became the new controlling condition for estimating SAY. The City estimated
the combined SAY from the two reservoirs as 6,940 acre‐feet per year (AFY). This estimate included the
anticipated loss of storage volume due to siltation through the year 2010. This estimate has been reported in
previous City planning documents, including the 2015 Urban Water Management Plan (UWMP) and the 2016
update to the General Plan Water and Wastewater Management Element. The 2015 UWMP, published in June
of 2016, was prepared during a period of extended drought, and it noted that the City planned to re‐calculate
the SAY when the on‐going drought came to an end.
During the winter of 2016‐2017, California received enough precipitation to provide some drought relief, and
the Department of Water Resources phased out its mandatory conservation guidelines. However, the state is
still in a period of below‐average precipitation. Figure 1 shows historical precipitation recorded at Salinas and
Whale Rock Reservoirs. For each month, the graph shows the average precipitation for the previous five‐year
period. This rolling five‐year average can be compared to the long‐term average, in this case the period from
1962 to 2016. The 1986‐1991 drought was preceded by a period of above‐average rainfall, and when the
drought ended the subsequent years had above‐average rainfall. By contrast, the current dry period has had a
much longer duration. Since 2003, the rolling average has been at or below the long‐term average, and at the
end of 2016 the rolling average reached the lowest value ever at Whale Rock. It remains to be seen whether
future years will bring enough precipitation to bring the rolling five‐year average back to its historical levels.
107 Page 397 of 476
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City SAY Model Update TM
Figure 1. Rolling Five-Year Average Precipitation at Salinas and Whale Rock
In early 2017, the City contracted with Water Systems Consulting, Inc. (WSC) to update the SAY model. The
update was intended to verify the historical input data, validate and document the calculations in the model,
incorporate the full extent of the 2006‐2016 drought, and generate scenarios that accounted for potential
climate change impacts.
Section 2: Model Updates
In January 2017, the City and Cal Poly began an update of the SAY model. Two major objectives of the project
were to update and verify the hydrologic input data and to develop scenarios that accounted for climate change
impacts. The SAY model was last updated in early 2015; therefore, the model that was used as the starting point
for this project is referred to as the 2015 model.
Verification of Input Data and Extension of Input Data Through January 2017
The 2015 model contained hydrologic input data for Whale Rock Reservoir and Salinas Reservoir through
February of 2015. While this data set contained values beginning in October of 1943, the source of the data had
not been documented. Furthermore, the construction of Whale Rock Reservoir was not completed until April of
1961, so there was nearly 18 years of data that predated the reservoir. According to the City’s records, the
(30.0)
(20.0)
(10.0)
0.0
10.0
20.0
30.0
0.0
10.0
20.0
30.0
40.0
50.0
60.0
Annual Inches of Rain at Whale RockAnnual Inches of Rain at Salinas. Salinas Rolling Five‐Year Average Salinas Average 1962 ‐ 2016
Whale Rock Rolling Five‐Year Average Whale Rock Average 1962 ‐ 2016
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hydrologic data predating the reservoir was generated through correlations between Salinas and Whale Rock
Reservoir lake levels and precipitation.
In order to load the model with verified historical hydrologic data, the City compiled the information that could
be traced to verified sources. Table 2 presents the data sets collected for this update as well as the start date of
each data series. All data sets were compiled through January of 2017, when the drought of 2006‐2016 had
subsided.
Table 2. Verified Hydrologic Data Start Date
Reservoir Precipitation Evaporation Inflow1 Downstream Releases
Salinas 7/1/1948 7/1/1970 4/1/1942 7/1/1942
Whale Rock 1/1/1962 10/1/1963 2/1/1962 2/1/1962
1Inflow for Whale Rock Reservoir calculated by Damsaver begins 6/1/1987. Inflow from 1962 to 1987 was calculated using paper records
compiled by City staff.
The inflow data for Whale Rock Reservoir came from two sources: Damsaver and paper records. Damsaver is
an Excel‐based tool that the City began to use in June 1987 to record and report Whale Rock Reservoir
hydrologic data, including the computation of monthly inflow. Prior to 1987, the City utilized a paper form to
record monthly precipitation, evaporation, reservoir elevation, reservoir storage, and water releases. To
generate a complete data set extending back to 1962, WSC performed mass balance1 calculations using data
from the paper records. The calculated inflows were validated using a 2.5‐year overlap period, 1987 to 1989,
when the City utilized both Damsaver and the paper forms. While there was variation from month to month, the
total calculated inflows over the 2.5‐year period were within 10 percent of the total produced using the
Damsaver software. Therefore, the pre‐1987 inflows calculated from the paper forms were considered
acceptable for use in this evaluation.
In general, the verified historical data compiled for this update was not significantly different than the input data
in the 2015 model. The exception was in recorded evaporation rates. For this update, historical evaporation
data was available for the period beginning July 1, 1970. The historical data in the previous model and the data
compiled for this study are shown in Figure 2 and Figure 3.
1 The mass balance calculation was based on the fact that monthly change in storage volume will be determined by the
inputs (precipitation and inflow) and outputs (evaporation and downstream releases) during that month. Historical data for
reservoir levels were used to calculate change in storage, and historical data was available for precipitation, evaporation,
and downstream releases. The team then solved for the only unknown variable, monthly inflow.
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Figure 2. Cumulative Evaporation Data for Salinas Reservoir, 1970-2015
Figure 3. Cumulative Evaporation Data for Whale Rock Reservoir, 1970-2015
For both reservoirs, the updated historical data show consistently higher evaporation rates than the data used in
the 2015 model. The difference results in evaporation losses approximately 30 percent higher than the 2015
model, leading to a reduction in the calculated SAY.
Climate Change Impacts
Although previous versions of the model included several scenarios with adjusted climatic patterns, they were
based on simple modifications to relatively short data sets. As part of this model update, a range of new
scenarios was added based on varying climate change projections identified by the U.S. Environmental
Protection Agency (EPA) and the San Luis Obispo Council of Governments (SLOCOG). The estimated changes in
climate associated with these scenarios were applied to the historical data set for inflows, precipitation, and
evaporation. The model was then used to calculate a revised SAY assuming that these conditions had prevailed
during the historical period of record.
‐
500
1,000
1,500
2,000
2,500
3,000
3,500
4,000
4,500
1970 1975 1981 1986 1992 1997 2003 2008 2014Cumulative Evaporation (inches)Salinas Cumulative Evaporation, Previous Model (inches)
Salinas Cumulative Evaporation, Verified Historical Data (inches)
‐
500
1,000
1,500
2,000
2,500
3,000
1970 1975 1981 1986 1992 1997 2003 2008 2014Cumulative Evaporation (inches)Whale Rock Cumulative Evaporation, Previous Model (inches)
Whale Rock Cumulative Evaporation, Verified Historical Data (inches)
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Section 3: Scenario Modeling
Scenario 1: 2015 Model
Scenario 1 runs the model using the hydrologic input data used in the 2015 model. As discussed previously, the
source of this hydrologic input data was not documented.
Scenario 2: Verified Historical Data
Scenario 2 utilizes the historical hydrological data set compiled for this update. Because this input data has been
verified against historical records, Scenario 2 is considered to be the baseline estimate for future conditions.
Scenarios 3 through 8: EPA CREAT Climate Change Projections
Scenarios 3 through 8 are based on climate change projections identified in the EPA’s Climate Resilience
Evaluation and Awareness (CREAT) Projection Map. CREAT was prepared by the EPA, specifically for drinking
water, wastewater and stormwater utility owners and operators, as an informational tool to assist in
understanding and addressing climate change risks. Projected changes in CREAT were derived from the
evaluation of thirty‐eight Global Climate Models recognized by the Intergovernmental Panel on Climate Change
(IPCC). Results from each model were recorded on a 0.5‐ by 0.5‐degree (approximately 34‐ by 34‐mile) grid basis
and compared to three statistical targets based on the distribution of the models. The five models closest to
each target were averaged to generate each projected temperature and precipitation change. The three targets
are defined as:
Hot/dry future conditions – Nearest to the 5th percentile of precipitation and 95th percentile of
temperature projections;
Central future conditions – Nearest to the 50th percentile of both precipitation and temperature
projections; and
Warm/wet conditions – Nearest to the 95th percentile of precipitation and 5th percentile of temperature
projections.
Projections are presented for two planning horizons: 2035, the midpoint of a range from 2024 to 2045, and
2060, the midpoint of a range from 2050 to 2070.
For the SAY model, it is assumed that the change in inflow is directly proportional to the change in precipitation.
Because of the uncertainty about the exact relationship between higher temperatures and increased
evaporation, future evaporation rates were assumed to be five percent higher than the verified historical data.
Projected changes are applied to the entire verified historical data set in Scenario 2.
Scenarios 9 through 12: SLOCOG Climate Change Projections
Scenarios 9 through 12 are based on climate change projections identified in the San Luis Obispo Council of
Governments (SLOCOG) 2014 Regional Transportation Plan. SLOCOG climate change projections reflect the
continuation of current energy‐subsidy policies, implying relatively high energy consumption and high
greenhouse gas (GHG) emissions. Per the SLOCOG report, this scenario closely followed the global emissions
path of the late 1990s. The SLOCOG report states that given a sharp rise in emissions since 2000, the climate
projections reflected may underestimate actual climate change.
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Like EPA’s CREAT tool, the SLOCOG projections are based on IPCC recognized Global Climate Models. However,
the SLOCOG study focuses specifically on three models: CSIRO (from Australia), MIROC (from Japan), and
HadCM (from the UK). The United States Department of Agriculture (USDA) Forest Service Mapped Atmosphere‐
Plant‐Soil System (MAPSS) team at the Pacific Northwest Research Station then converted the model output to a
locally‐relevant scale of 8 kilometers (km) using local temperature and precipitation pattern data.
As with the EPA CREAT projections, SLOCOG projections are presented as a percent difference in precipitation
and degree difference in temperature, and are assigned to two planning horizons, 2035 to 2045 and 2075 to
2085. The SLOCOG projections, however, are presented as a range for each window of time. Therefore, a
scenario was created for the climatic lower bound and upper bound for each planning horizon.
As with Scenarios 3 through 8, Scenarios 9 through 12 apply the respective climate change projections to the
verified historical data set (Scenario 2) and adjust the inflow proportionally to the change in precipitation, while
evaporation rates were assumed to be five percent higher than historical values.
Scenario 13: Nature Climate Change Evaluation
Nature Communications, a peer‐reviewed open access scientific journal published by the Nature Publishing
Group, published an article in in July of 2017 that presented an overview of various climate models and their
predictions for future precipitation in California. This work found that under future conditions, California could
receive more precipitation in response to global warming. It found that the anticipated changes in air circulation
patterns were reminiscent of an El Nino event, which can lead to an increase in storm track activity in the east
Pacific.
The article concluded that central California could expect on the order of three inches per year in additional
rainfall attributable to global warming. The historical average annual rainfall at Salinas Dam is approximately 23
inches, while the annual average at Whale Rock Reservoir is approximately 19 inches. As a conservative
estimate, it was assumed that under this scenario, precipitation and runoff values would increase 15 percent
over their historical values. Evaporation rates were assumed to be 5 percent higher than historical values.
Section 4: Model Results
The updated spreadsheet model is intended to be a tool that the City can use to evaluate SAY under potential
future conditions. Several simulations were run during the development of the spreadsheet, and the results are
summarized in the following tables. These preliminary results are intended to show the range of potential
values under differing input assumptions. As discussed further in the Appendix, the model is set up to account
for loss of reservoir capacity due to siltation up to, and including, the designated simulation year. The model
results presented in Tables 3 through 5 account for the estimated siltation through 2017.
The model was first used to determine the impact of using verified historical data as inputs. The results are
summarized in Table 3. For consistency with previous estimates, these results do not include the 2006 ‐ 2016
drought. These results are presented for comparison with previously reported values of SAY. Using the raw
input data from the 2015 model, the updated model showed that an annual withdrawal of 6,940 AFY could be
sustained. With the incorporation of the updated evaporation data, the corresponding value is 6,590 AFY.
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Table 3. Safe Annual Yield Model Outputs with Verified Historical Data
2015 Model SAY
(AFY)
Updated Model SAY with Verified
Historical Data (AFY)
SAY (Period of record ending 2006; does not
include the 2006‐2016 drought)
6,940 6,590
Note: These results are the combined City SAY from Salinas and Whale Rock Reservoirs, based on a
joint operating strategy
The model was then used to calculate an updated SAY for the entire period of record, including the 2006 – 2016
drought. These results are shown in Table 4. This drought was more severe than the 1986‐1991 drought, and it
has become the new controlling condition for the estimation of SAY. The estimated SAY is 4,910 AFY,
approximately 2,000 AFY less than the previously used estimate of 6,940 AFY.
Table 4. Safe Annual Yield Model Outputs Incorporating 2006 – 2016 Drought
Updated Model SAY with Verified
Historical Data (AFY)
SAY (Period of record through 2016; includes the 2006‐2016
drought)
4,910
Note: These results are the combined City SAY from Salinas and Whale Rock Reservoirs, based on a
joint operating strategy
Finally, the model was used to simulate a range of potential climate change scenarios. These estimates are
summarized in Table 5. There is considerable uncertainty about how climate change will impact the
precipitation and evaporation patterns on the Central Coast. The range of values provides an indication of
potential future conditions that might occur, but it is not yet feasible to identify an expected value for future
SAY.
Table 5. Safe Annual Yield Model Outputs for Climate Change Scenarios
Range of SAY
under EPA
Climate Change
Scenarios (AFY)
Range of SAY
under SLOCOG
Climate Change
Scenarios (AFY)
Nature Climate
Change
Scenario (AFY)
SAY (Period of record through 2016; includes the
2006‐2016 drought)
4,690 – 5,050 4,050 – 5,070 4,950
Note: These results are the combined City SAY from Salinas and Whale Rock Reservoirs, based on a joint
operating strategy
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Section 5: Conclusion
The City’s spreadsheet model for estimating SAY from Salinas and Whale Rock Reservoirs was updated to
incorporate verified historical data and the full extent of the most recent drought (2006 – 2016). The revised
estimate for the SAY from these reservoirs is 4,910 AFY, approximately 2,000 AFY less than the value of 6,940
AFY used in previous planning documents. Two factors contributed to this decline. First, the historic
evaporation data in the model were revised to match currently available records. Second, the updated model
includes the full extent of the 2006‐2016 drought. This dry period was more severe than the 1986‐1991
drought, and it is the new controlling period for estimating SAY.
The updated spreadsheet model can be used to estimate the SAY under a variety of scenarios. The spreadsheet
can also be used to demonstrate the advantages of coordinating the use of the City’s water supply sources,
rather than analyzing each source in isolation. It is recommended that the City and Cal Poly continue to
coordinate their analyses of the expected supply from Whale Rock. The model should also be kept up‐to‐date
with additional hydrological data, as it becomes available.
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Appendix A: Model Layout
The updated model has been restructured to provide a more user‐friendly and transparent interface. This
appendix briefly describes key tabs in the spreadsheet model.
Dashboard Tab
The primary components of the Dashboard tab, circled in blue in Figure A‐1, are the Modeled Scenario
dropdown list, the City Withdrawal Mode selection, and the Solve buttons. The Modeled Scenario dropdown list
allows the user to select the scenario of interest. The City Withdrawal Mode allows the user to calculate
separate SAY’s for Salinas and Whale Rock Reservoir, or to model them as joint, or coordinated, use. When Joint
Use is selected, the model prioritizes withdrawal from Salinas Reservoir and provides a single SAY for the two
reservoirs. The Solve buttons allow the user to run the model without having to manually iterate to the desired
solution. The Solve buttons count down the SAY from 100,000 AFY until the total unmet demand is equal to zero
over the entire time series.
Just above the Modeled Scenario dropdown list is a summary of assumptions and input data. These assumptions
and inputs have been discussed with the City and Cal Poly, and therefore likely will not change on a regular
basis, but they should always be reviewed prior to a model run.
Figure A-1. Dashboard Tab Screenshot
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Scenario Tab
As discussed in Section 2, a suite of new scenarios has been incorporated into the updated model. All scenarios
are defined on the Scenarios tab, including the scenario number and respective percent change in inflow,
precipitation, and evaporation. While a temperature change in degrees Fahrenheit is listed, it is not currently
being included in the calculations. All future scenarios are expected to have higher temperatures, which will lead
to increased evaporation, but there is uncertainty about how much evaporation will increase. In addition to
defining the scenario criteria, this tab is used to manually record the calculated SAY for each scenario.
Bathymetry Tab
The Bathymetry tab houses the stage‐storage‐area relationships for the two reservoirs. For Salinas Reservoir,
the relationship is based on the Salinas Reservoir Bathymetric survey conducted in 1990. The annual siltation
was estimated to reduce available storage in Salinas Reservoir by 40 AFY, based on the 1990 bathymetric survey.
For Whale Rock Reservoir, the relationship is based on the Whale Rock Reservoir Bathymetry survey conducted
in 2013. As part of the 2013 bathymetric survey, the annual siltation was estimated to reduce available storage
by 32.6 AFY. These siltation rates can be found on the Dashboard tab along with the year of the associated
bathymetric survey.
The user can select a year to run the simulation, and the model will reduce the full capacity of each reservoir to
account for the expected siltation between the date of the respective bathymetric survey and the simulation
year. The City’s water supply planning policy already includes an expected reduction in future water supply of
500 AFY to account for reservoir siltation. Therefore, the model simulations run for this project used a
simulation year of 2017 to estimate the SAY under current conditions.
Demand Patterns Tab
The Demand Patterns tab defines the monthly demand multipliers for the City, Cal Poly, CMC, and Cayucos
water deliveries. For the updated model, the City demand pattern has remained the same as in the previous
model. The State demand pattern has been split into two new Cal Poly demand patterns, domestic and
agricultural, and an evenly distributed demand pattern for the CMC. Cal Poly provided domestic and agricultural
usage data from 1992 through 2016, which was used to refine the Cal Poly demand patterns. The demand
patterns are shown in Figure A‐2.
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Figure A-2. Demand Patterns
Calculations Tab
The Calculations tab has inputs and formulas organized in a progression from left to right, with one row for
every month. Row 7 on the Calculations tab defines whether a column is an input value or a formula. Input
values are historical monthly hydrologic inputs including natural inflow volume, precipitation depth, and
evaporation depth. Input values should be added to the model as new data is collected over time. As input
values are added, the remainder of the cells in that row should be populated by dragging down the formulas
from the cell above.
Column Descriptions Tab
This tab contains descriptions for each column on the Calculations tab. Column descriptions include a written
description and a display of the respective formula. This tab provides more detailed information about the
calculations embedded in the spreadsheet.
0.00%
2.00%
4.00%
6.00%
8.00%
10.00%
12.00%
14.00%
16.00%
18.00%
123456789101112Monthly Demand MultiplierMonth
City Monthly Demand Multiplier Cayucos Deliveries Monthly Demand Multiplier
Cal Poly AG Monthly Demand Multiplier Cal Poly Domestic Monthly Demand Multiplier
CMC Monthly Demand Multiplier
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Appendix F – Annual Water Supply and Demand Assessments
The City prepares Annual Water Supply and Demand Assessments to evaluate near -term water supply
availability, projected demands, infrastructure constraints, and potential shortage conditions. These
assessments support implementation of the City’s Water Shortage Contingency Plan and provide annual
updates regarding water supply conditions. Because the assessments are prepared annually and may be
updated independently of the UWMP, this appendix provides a summary and public links to the assessment
documents rather than reproducing each full assessment within the UWMP.
2022-2026 Water Supply and Demand Assessment Documentation
Assessment Year Council Date Report Link
2026 June 16, 2026 Link to be provided following the June 16, 2026,
City Council Meeting
2025 May 20, 2025 2025 Water Supply and Demand Assessment
2024 June 4, 2024 2024 Water Supply and Demand Assessment
2023 May 16, 2023 2023 Water Supply and Demand Assessment
2022 May 3, 2022 2022 Water Supply and Demand Assessment
Notes: A link to the 2026 WSCP link will be provided in this UWMP following the June 16, 2026 City Council
meeting where the 2026 Water Supply and Demand Assessment, 2025 Urban Water Management Plan, and 2025
Water Shortage Contingency Plan will be brought before the City Council for review and/or adoption.
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Appendix G – Seismic Risk / Hazard Mitigation Plan Reference
Purpose
California Water Code section 10632.5 requires urban water suppliers to include a seismic risk assessment
and mitigation plan as part of the Urban Water Management Plan. Pursuant to California Water Code
section 10632.5(c), an adopted Local Hazard Mitigation Plan or Multi-Jurisdictional Hazard Mitigation Plan
may be incorporated into an Urban Water Management Plan to satisfy this requirement if the plan
addresses seismic risk.
The City of San Luis Obispo satisfies this requirement by incorporating by reference the 2025 –2030 San
Luis Obispo County Multi-Jurisdictional Hazard Mitigation Plan (MJHMP), including the applicable City of
San Luis Obispo jurisdictional annex and related hazard mitigation materials.
Incorporated Document
•Document Title: 2025–2030 San Luis Obispo County Multi-Jurisdictional Hazard Mitigation Plan
•Lead Agency: County of San Luis Obispo
•Participating Jurisdiction: City of San Luis Obispo
•UWMP Reference Section: Chapter 8, Section 8.2.1, Seismic Risk Assessment and Mitigation
•Public Access: The full MJHMP, jurisdictional annexes, and supporting appendices are available
through the County of San Luis Obispo Office of Emergency Services website.
Incorporation by Reference
The 2025–2030 San Luis Obispo County MJHMP is incorporated by reference into the City’s 2025 UWMP
for purposes of complying with California Water Code section 10632.5. The MJHMP evaluates regional and
local hazards, including earthquake and liquefaction hazards, and identifies mitigation strategies intended
to reduce risk to people, property, infrastructure, and essential services.
The MJHMP includes information relevant to the City’s water system, including seismic hazards,
liquefaction susceptibility, critical facility vulnerabilities, utility system impacts, emergency response
coordination, infrastructure resilience, and mitigation planning. The City uses information contained in the
MJHMP to support emergency preparedness planning, capital improvement prioritization, infrastructure
resiliency efforts, and interagency coordination during emergency response and recovery.
Relationship to the UWMP
Chapter 8 of the City’s 2025 UWMP summarizes the City’s seismic risk assessment and mitigation
approach and identifies the MJHMP as the planning document incorporated by reference to satisfy
California Water Code section 10632.5. The UWMP also describes the City’s Water Shortage Contingency
Plan, emergency supply resiliency considerations, and potential causes of water shortage conditions,
including seismic events that could affect dams, reservoirs, pipelines, tanks, pump stations, treatment
facilities, or distribution system infrastructure.
Document Availability
The full MJHMP is not reproduced in this appendix due to its size and because it is maintained as a separate
County-led regional planning document. Instead, the MJHMP is incorporated by reference and made
available through the County of San Luis Obispo Off ice of Emergency Services website.
•Public link: 2025 Multi-Jurisdictional Hazard Mitigation Plan
Version Control
If the 2025–2030 San Luis Obispo County MJHMP is amended, updated, or replaced after adoption of this
UWMP, the City may continue to rely on the most current adopted hazard mitigation planning document,
as applicable, for emergency preparedness, infrastruc ture resiliency, and seismic risk mitigation planning.
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Updates to the MJHMP may occur independently of the UWMP process in accordance with applicable
federal, state, and local requirements.
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Appendix H – Water Shortage Contingency Plan
The City’s WSCP is available for review and comment at https://www.slocity.org/government/department-
directory/utilities-department/documents-and-files. Following adoption of the UWMP and WSCP, the
WSCP will be added as appendix H.
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Contingency Plan
(PUBLIC REVIEW DRAFT)
This plan was adopted on __________, 2026
pursuant to San Luis Obispo City Council
Resolution No. ________ (2026 series)
San Luis Obispo City Council
Erica A. Stewart, Mayor
Emily Francis, Vice Mayor
Jan Marx
Michelle Shoresman
Michael R. Boswell
Plan Prepared by:
City of San Luis Obispo, Public Works and Utilities Department
Utilities Branch
879 Morro Street
San Luis Obispo, CA 93401
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TABLE OF CONTENTS
SECTION 1: INTRODUCTION .......................................................................................................................... 5
SECTION 2: WATER SUPPLY RELIABILITY ANALYSIS & ANNUAL ASSESSMENT PROCESS .............................. 5
2.1 Relationship to the UWMP & Water Supply and Demand Assessment ...................................... 5
2.2 Annual Water Supply & Demand Assessment ............................................................................. 6
2.3 Five-Year Drought Risk Assessment ............................................................................................ 8
2.4 Water Supply Reliability Findings ................................................................................................ 8
SECTION 3: WATER SHORTAGE RESPONSE FRAMEWORK ............................................................................ 8
3.1 Relationship to State Standard Shortage Levels.......................................................................... 9
3.2 City Council Declaration & Implementation .............................................................................. 10
SECTION 4: WATER SHORTAGE STAGES AND RESPONSE ACTIONS ............................................................ 10
4.1 Overview .................................................................................................................................... 10
4.2 Water Shortage Response Stage: Monitor ................................................................................ 11
4.3 Water Shortage Response Stage: Watch ................................................................................... 11
4.4 Water Shortage Response Stage: Warning ............................................................................... 13
4.5 Water Shortage Response Stage: Alert .....................................................................................14
4.6 Water Shortage Response Stage: Severe .................................................................................. 15
4.7 Water Shortage Response Stage: Extreme ................................................................................ 15
4.8 Water Shortage Response Stage: Critical .................................................................................. 16
SECTION 5: COMMUNICATION, COMPLIANCE, AND ENFORCEMENT ........................................................ 16
5.1 Communication Protocols ......................................................................................................... 16
5.2 Customer Compliance & Enforcement ...................................................................................... 17
5.3 Legal Authorities ........................................................................................................................17
SECTION 6: WATER BUDGETS, EXEMPTIONS, AND APPEALS ...................................................................... 17
6.1 Water Budgets & Allotments ..................................................................................................... 17
6.2 Exemptions & Adjustments ....................................................................................................... 18
6.3 Appeals ...................................................................................................................................... 19
SECTION 7: REVENUE AND EXPENDITURE IMPACTS ................................................................................... 19
SECTION 8: MONITORING, REPORTING, AND REFINEMENT PROCEDURES ................................................ 20
SECTION 9: CATASTROPHIC WATER SUPPLY INTERRUPTION ..................................................................... 20
9.1 Seismic Risk and Hazard Mitigation Planning ............................................................................ 21
9.2 Emergency Response and Mutual Aid ....................................................................................... 21
9.3 Emergency Response Actions .................................................................................................... 21
SECTION 10: ADOPTION, SUBMITTAL, AND AVAILABILITY ......................................................................... 22
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APPENDIX I: STANDARDIZED TABLES .......................................................................................................... 23
APPENDIX II: PUBLIC HEARING NOTICE ...................................................................................................... 27
APPENDIX III: ADOPTION RESOLUTION ....................................................................................................... 29
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WSCP-5
SECTION 1: INTRODUCTION
The City’s Water Shortage Contingency Plan (WSCP)
establishes the framework the City will use to prepare for and
respond to water shortage conditions. A water shortage may
occur when available water supplies are insufficient to meet
anticipated customer demands or when operational, regulatory,
environmental, or emergency conditions limit the City’s ability
to access, convey, treat, or deliver water supplies.
Water shortages may result from drought, climate change,
infrastructure failure, water quality impacts, regulatory restrictions, power outages, seismic events, wildfire,
flooding, or other emergency conditions. Because shortage conditions can vary in cause, severity, duration,
and timing, this WSCP is intended to provide a flexible and implementable framework for reducing demand,
extending available water supplies, protecting public health and safety, and maintaining essential water
service.
This WSCP is prepared in coordination with the City’s 2025 Urban Water Management Plan (UWMP). The
UWMP evaluates the City’s water supply reliability under normal-year, single dry-year, multiple dry-year,
and five-year drought risk assessment conditions. This WSCP describes the shortage response procedures
and actions the City may implement if the annual Water Supply and Demand Assessment, the City’s Water
Projection Model, or another operational evaluation
indicates that available supplies may be insufficient to meet
expected demands.
The City’s Water Conservation Ordinance, Chapter 13.07
of the San Luis Obispo Municipal Code, establishes
regulations and procedures related to water conservation
and water shortage response. The City may also implement
shortage response actions through City Council resolution,
ordinance, emergency declaration, or other appropriate
legal authority depending on the nature and severity of the
shortage.
The City’s water supply reliability is supported by a diverse portfolio of potable and non -potable supplies,
including Salinas Reservoir, Whale Rock Reservoir, Nacimiento Reservoir, recycled water, and planned
groundwater extraction. The City has also invested in conservation programs, water treatment facilities,
conveyance and distribution infrastructure, storage, backup power, and emergency response capabilities
that improve the City’s ability to manage those supplies effectively. Together, these investments reduce
overreliance on any single source of supply and provide operational flexibility during droughts, infrastructure
disruptions, and other water supply challenges. However, the City must retain the ability to respond to
changing conditions if actual or projected supplies decline, demands exceed expected levels, or operational
constraints limit the City’s ability to access, treat, or deliver water.
SECTION 2: WATER SUPPLY RELIABILITY ANALYSIS & ANNUAL
ASSESSMENT PROCESS
2.1 Relationship to the UWMP & Water Supply and Demand Assessment
Water supply reliability is the City’s ability to meet customer water demands under varying hydrologic,
operational, regulatory, infrastructure, and demand conditions. The City evaluates water supply reliability
through several related planning documents, including the UWMP, the annual Water Supply and Demand
Assessment, and this WSCP. Each document serves a different purpose, but together they support the
City’s evaluation of water supply conditions and potential shortage response needs.
The California Department of Water
Resources defines drought as:
“A deficiency of precipitation over an
extended period of time resulting in a
water shortage for some activity,
group, or environmental sector.”
TABLE 1: RESERVOIR STORAGE
Reservoir Percent of
Capacity
Salinas 100%
Whale Rock 86%
Nacimiento 61%
Notes: Reservoir volumes are as of May 2026.
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➢The UWMP provides a detailed assessment of the City’s long-term and short-term water supply
reliability;
➢The annual Water Supply and Demand Assessment evaluates water supply reliability for the
upcoming fiscal year and supports the City’s annual shortage determination; and
➢The WSCP establishes the staged actions the City may take if shortage conditions occur in the
upcoming year or future years.
2.2 Annual Water Supply & Demand Assessment
The annual Water Supply and Demand Assessment evaluates the City’s water supply reliability for the
current year and one upcoming dry year. The City may evaluate additional dry-year conditions at its
discretion if doing so would assist with water supply planning, drought preparedness, or City Council
decision-making.
The UWMP provides the City’s primary water supply reliability analysis. It forecasts the City’s ability to meet
projected water demands under normal-year, single dry-year, multiple dry-year, and five-year drought risk
assessment conditions. The UWMP distinguishes between methodologies used for long-term water supply
planning and shorter-term reliability analysis.
For long-term water supply planning, the UWMP evaluates whether the City’s planned water supply portfolio
is sufficient to meet projected demands over the UWMP planning horizon from 2025 through 2050. This
analysis is informed by the policy framework established in the General Plan and Water and Wastewater
Element. Long-term demand planning is based on General Plan population assumptions and the City’s 117
gallons per capita per day planning value. Long-term supply planning is based on established planning
values for the City’s water supply portfolio, including Nacimiento Reservoir, Salinas and Whale Rock
Reservoirs, recycled water use, planned groundwater when available, and long-term planning adjustments
such as the 500 acre-foot reservoir siltation planning adjustment. This long-term analysis is intended to
evaluate the City’s ability to serve projected growth and demands through the UWMP planning horizon.
The UWMP also includes shorter-term reliability analyses required by the Urban Water Management
Planning Act, including single dry-year, multiple dry-year, and five-year drought risk assessment analyses.
These analyses evaluate how the City’s supplies are expected to perform under dry conditions and other
reliability assumptions. The five-year drought risk assessment evaluates whether supplies are expected to
be sufficient if the City were to experience five consecutive dry years during the required assessment
period. Unlike the long-term General Plan and Water and Wastewater Element planning methodology, the
five-year drought risk assessment uses current and projected near-term conditions to evaluate supply
reliability. These conditions may include current and projected reservoir storage, recent demand, source
availability, infrastructure constraints, recycled water availability, groundwater project status, dry-year
assumptions, and Water Projection Model results.
The annual Water Supply and Demand Assessment serves a related but more focused purpose. Prepared
annually by City staff, the assessment evaluates whether available supplies are sufficient to meet
anticipated demands during the upcoming fiscal year, referred to as the assessment period. The annual
assessment is a near-term operational and water supply reliability analysis that supports the City’s annual
determination of whether a water shortage is anticipated and whether response actions under this WSCP
may be needed. Like the UWMP’s five-year drought risk assessment, the annual Water Supply and
Demand Assessment relies on current and projected near-term conditions rather than long-term General
Plan buildout assumptions.
This WSCP is an implementation and response document. It does not duplicate all of the UWMP’s reliability
tables or the detailed analysis included in the annual Water Supply and Demand Assessment. Instead, it
incorporates the UWMP’s reliability analysis by reference, including the long-term reliability findings and
shorter-term drought reliability analyses, and relies on the annual Water Supply and Demand Assessment
and Water Projection Model to support near-term shortage determinations. Together, these documents
help determine whether the City should remain in normal operations or consider implementation of staged
response actions under this WSCP.
This structure keeps each document in its proper role:
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The City’s annual assessment process includes the following general steps:
1.Review current water supply conditions.
Staff review current reservoir storage, precipitation, hydrologic conditions, source -specific
availability, water quality conditions, regulatory considerations, and other factors that may affect
the City’s ability to access, treat, convey, or deliver water.
2.Estimate current-year unconstrained demand.
Staff estimate anticipated customer demand for the assessment period before applying any new
shortage response actions triggered by that year’s assessment. This estimate may consider recent
potable and non-potable water use, seasonal demand patterns, weath er, population, expected
near-term growth, land use changes, customer class trends, prior conservation levels, and other
factors that may influence demand.
3.Quantify current-year available supply.
Staff quantify available supplies from each applicable source, including Salinas Reservoir, Whale
Rock Reservoir, Nacimiento Reservoir, recycled water, and groundwater, if available. The
assessment considers hydrologic and regulatory conditions for the cur rent year and one dry year,
as well as source-specific operational limitations.
4.Evaluate infrastructure capabilities and plausible constraints.
Staff evaluate whether existing infrastructure can access, treat, convey, store, and distribute the
water supplies identified in the assessment. This may include consideration of treatment capacity,
transmission and conveyance limitations, pump station availability, reservoir operations,
distribution system constraints, groundwater project status, temporary outages, planned
maintenance, emergency repairs, and other operational limitations. Temporary conveyance
constraints may be incorporated when applicable.
5.Apply dry-year assumptions.
Staff evaluate available supplies under applicable dry-year assumptions. These assumptions may
include reduced reservoir inflows, increased evaporation, reduced precipitation, higher seasonal
demand, reduced source availability, water quality limitations, o r other conditions that could affect
supply reliability during a dry year.
6.Use locally applicable evaluation criteria.
The City will consistently rely on locally applicable evaluation criteria to determine whether shortage
conditions may exist. These criteria may include projected monthly supply and demand balances,
total projected annual surplus or shortage, estimated years of available water supply remaining,
reservoir storage conditions, source-specific operational availability, infrastructure constraints,
recycled water availability, groundwater availability, and whether projected conditions correspond
to a WSCP shortage stage.
7.Evaluate results using the Water Projection Model.
The City uses its Water Projection Model to support the annual assessment. The model evaluates
projected demand, available supplies, source-specific assumptions, infrastructure constraints, dry -
year conditions, and the estimated number of years of available water supply remaining under the
input conditions. The model allows the City to evaluate near-term reliability based on actual and
expected conditions rather than relying solely on long-term planning assumptions.
8.Determine whether WSCP response actions may be needed.
If the annual assessment indicates that projected supplies are sufficient to meet projected demands
and that available supplies are expected to remain above the City’s established years -of-supply
thresholds, no shortage response action may be required. If the assessment indicates that supplies
may be insufficient, or that available supplies have declined below a WSCP stage threshold, staff
may recommend that the City Council declare the applicable shortage stage and implement
appropriate response actions.
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9.Report findings and submit required information to the State Department of Water
Resources (DWR).
Staff will generally present the annual assessment to the City Council in May or June of each year.
Following review, the City will submit the required annual water shortage assessment information
to DWR by July 1, consistent with California Water Code requirements.
The annual assessment is intended to provide a consistent decision-making process while allowing the City
to account for changing hydrologic, operational, regulatory, infrastructure, and demand conditions. Because
actual conditions may vary from year to year, the assessment may result in a recommendation to remain
in normal operations, declare a WSCP shortage stage, modify previously adopted response actions, or take
other actions necessary to protect public health, safety, and essential water service.
2.3 Five-Year Drought Risk Assessment
The Urban Water Management Planning Act requires that the City conduct a five-year Drought Risk
Assessment as part of the UWMP. The assessment evaluates whether the City’s projected water supplies
would be sufficient to meet projected water demands during a period simulating five consecutive dry years.
This analysis provides a shorter-term reliability outlook than the UWMP’s long-term planning horizon and
helps identify whether potential shortage conditions could occur during the five-year assessment period.
This assessment is particularly relevant to this WSCP because the City’s shortage response framework is
structured around years-of-supply thresholds. These thresholds are intended to help the City identify
potential shortage conditions before supplies are exhausted and before more severe response actions
become necessary. By evaluating supply reliability across a five-year dry period, the assessment helps to
determine whether available supplies are sufficient to maintain normal operations or whether the City may
need to consider staged response actions under this WSCP.
2.4 Water Supply Reliability Findings
The City’s 2025 UWMP and conclude that the City’s diversified water supply portfolio, planned groundwater
restoration, recycled water program, conservation efforts, and ongoing infrastructure investments provide
a reliable basis for meeting projected water demands through the 2025-2050 UWMP planning horizon. The
City’s reliability analyses show that projected supplies are expected to be sufficient to meet projected
demands under normal-year, single dry-year, multiple dry-year, and five-year drought risk assessment
conditions.
Actual conditions may differ from the assumptions used in the UWMP or annual assessment. Potential
causes of reduced supply include extended drought, infrastructure failure, wildfire, water quality impacts,
regulatory changes, treatment or conveyance limitations, groundwater production delays, groundwater
basin management constraints, reduced recycled water availability, or demand conditions that differ from
projections. If such conditions result in a projected or actual shortage, the City may implement this WSCP.
Identifying a potential shortage multiple years in advance is a responsible water management practice.
Early identification provides time for the City to implement phased demand reduction measures, increase
public outreach, adjust operations, preserve reservoir storage, evaluate supplemental supplies, and avoid
more abrupt or disruptive restrictions later. Early identification also allows the City Council, staff, customers,
and regional partners to respond in a measured and coordinated manner before shortage conditions
become more severe.
SECTION 3: WATER SHORTAGE RESPONSE FRAMEWORK
The City’s water shortage response stages provide a structured framework for escalating response actions
as water supply conditions worsen. The stages are intended to reduce demand, extend available supplies,
preserve water for public health and safety, and provide time for additional rainfall, supplemental supplies,
infrastructure repairs, or operational adjustments to improve supply conditions.
The City’s local shortage stages are informed by the Water Projection Model’s estimate of the number of
years of available water supply remaining based on defined inputs. This years-of-supply approach reflects
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the City’s local water supply planning framework and allows the City to identify potential shortage conditions
before supplies are insufficient to meet demand. To maintain consistency with State reporting requirements,
the City maps each local stage to the State’s six standard shortage levels, which are expressed as
percentage shortage ranges. When declaring a shortage stage and selecting response actions, the City
Council would consider the Water Projection Model results, the applicable local shortage stag e, the
corresponding State shortage level, and the specific supply, demand, infrastructure, and operational
conditions causing the potential shortage.
3.1 Relationship to State Standard Shortage Levels
California Water Code Section 10632 requires six standard water shortage levels corresponding to
progressive shortage ranges of up to 10 percent, 20 percent, 30 percent, 40 percent, 50 percent, and
greater than 50 percent. The City’s WSCP includes a Monitor Stage that represents normal conditions
where greater than five years of water supply are available and the City’s ongoing conservation program is
in place. The six shortage levels required by the Water Code begin with the City’s Watch Stage and
progress through the Critical Stage, as shown in Table 2.
The City’s shortage stages are intended to operate cumulatively. Unless modified, suspended, or replaced
by City Council action, actions implemented during a lower shortage stage would remain in effect when the
City moves to a higher shortage stage. For example, actions implemented during the Watch Stage would
remain in effect during the Warning Stage, and the Warning Stage would add additional measures intended
to further reduce demand. As a result, the percentage shortage ranges shown in Table 2 represent
cumulative shortage-response targets, while the measures described for each stage generally identify the
additional actions that may be implemented as conditions worsen.
TABLE 2: Water Shortage Response Stages Quick Reference Guide
STAGE WATER SUPPLY
STATUS1 CITY ACTIONS
Monitor 5+ years of available
water supply
City maintains existing water conservation staffing levels and budget that
supports meeting internal water efficiency goals and regulatory
requirements for water conservation, including ongoing public outreach.
Watch
< 5 years of available
water supply
(up to 10% water
shortage)
City increases programs that encourage voluntary water conservation
including public outreach, rebate programs, and water efficient fixture
giveaways. City examines available alternative water sources (groundwater
expansion, recycled water filling stations, water purchase agreements, etc.),
City modifies internal operations to focus on decreasing water loss and
prepares for subsequent WSCP stages. City ceases any short-term outside-
City water sales/leases.
Warning
< 4.5 years of
available water
supply
(up to 20% water
shortage)
City implements time of use irrigation restrictions (7:00 PM – 7:00 AM). City
increases staffing, budget, and outreach to achieve additional voluntary
conservation savings while preparing for Alert-Critical stages.
Alert
< 4 years of available
water supply
(up to 30% water
shortage)
City requires mandatory conservation measures including outdoor irrigation
restrictions (four day a week watering) and considers a Water Offset
Program for new connections.
Severe
< 3.5 years of
available water
supply
City implements Water Allotment Program. Water Offset Program for new
connections may be increased (1.5:1 or 2:1 offset ratio). Allowable irrigation
reduced to three days per week.
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(up to 40% water
shortage)
Extreme
< 3 years of available
water supply
(up to 50% water
shortage)
City continues to implement a Water Allotment Program with reduced
allotment levels. Water Offset Program for new connections may be
increased (3:1 or 4:1 offset ratio). Allowable irrigation reduced to two days
per week with optional additional measures limiting turf and spray irrigation.
Critical
< 2.5 years of
available water
supply
(>50% water
shortage)
City continues to implement a Water Allotment Program at further reduced
levels (minimum for public health and safety). Irrigation no longer permitted.
Water Offset Program to cease and no new connections permitted.
If the annual assessment, five-year drought risk assessment, or another operational evaluation indicates
that available supplies may be insufficient to meet expected demands, City staff would evaluate the
appropriate WSCP stage and provide recommended response actions to the City Council for consideration.
The City Council would then declare the applicable water shortage stage1 and authorize implementation of
specific shortage response actions through resolution, ordinance, emergency declaration, or other
appropriate action.Outside of potential drought conditions, the City may also implement emergency
response actions through the same process if a sudden supply interruption, infrastructure failure, water
quality issue, power outage, or other emergency resulted in the need for immediate action to protect public
health, safety, or essential water service.
NOTE: The City’s Water Supply Status is informed by the Water Projection Model described in Section 2 of this Water
Shortage Contingency Plan.
3.2 City Council Declaration & Implementation
The City is not required to implement every action listed in a stage during every shortage event, nor is the
list of actions in this WSCP intended to be exclusively relied upon. Response actions may be tailored to the
specific circumstances of the shortage, including hydrologic conditions, reservoir storage, infrastructure
constraints, treatment capacity, customer demand, time of year, and expected shortage duration.
SECTION 4: WATER SHORTAGE STAGES AND RESPONSE ACTIONS
4.1 Overview
The City’s water shortage response may combine demand reduction measures, public outreach,
operational changes, supply augmentation, enforcement, financial measures, and administrative actions.
Response actions generally increase in intensity as shortage conditions become more severe.
Outdoor irrigation restrictions are an important component of the City’s response strategy because a
substantial portion of seasonal demand is associated with landscape irrigation. Outdoor water uses are
often discretionary, visible, and easier to monitor than many indoor uses. However, the City may also
implement indoor water efficiency measures, customer-specific water budgets, water allotments, water
waste enforcement, and other measures as needed.
The response actions described in this section are cumulative unless otherwise directed by the City Council.
Measures implemented during earlier shortage stages are expected to remain in effect during later shortage
stages, with additional or more restrictive measures added as needed to address the increasing shortage
level. Accordingly, references to an “additional” reduction in later stages are intended to describe the
1 When required by applicable conditions, the City Council shall declare a water shortage emergency in accordance
with California Water Code Chapter 3, Section 350. The City shall coordinate with the County of San Luis Obispo and
any other applicable local agency regarding the possible proclamation of a local emergency, as defined in Government
Code Section 8558.
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incremental savings sought from the new measures added at that stage, not the total cumulative reduction
target.
4.2 Water Shortage Response Stage: Monitor
The City of San Luis Obispo has made water conservation an integral part of the community’s values,
culture, and policy context for managing its water resources. The community has demonstrated a high
commitment to reducing its water usage during and outside of water shortages. Although not an actual
declaration of a water shortage, the Water Shortage Contingency Plan’s Monitor Stage remains in place at
all times along with voluntary conservation.
This stage is focused on achieving voluntary water savings, as opposed to mandatory demand reduction
programs. To ensure the City is using water responsibly and remaining in compliance with water efficiency
goals and regulations, the City continually assesses available water supply levels, monitors customer water
demand trends, conducts water loss audits, and evaluates potential supplemental supply projects. The
following are examples of demand management measures that may be taken to maintain water use
efficiency goals:
1.Implement public outreach and communication programs (bill stuffers, social media, etc.).
2.Participate in trade shows, home shows, and special community events.
3.Offer complimentary water audits.
4.Identify and notify customers of possible leaks and inefficient uses of water .
5.Encourage the use of drip irrigation and drought tolerant plants.
6.Implement school (K-12) education programs related to water conservation.
7.Enforce the water efficiency retrofit program (toilet retrofit upon sale program).
Actions at the Monitor Stage would also include active enforcement of the City’s water waste prohibitions,
such as those from Chapter 13.07 of the City’s Municipal Code, which defines water waste as follow s:
4.3 Water Shortage Response Stage: Watch
When the City’s available water supply would provide less than five years of water, staff would recommend
to the City Council that they adopt a resolution declaring a water shortage and to enter the Watch Stage
and urge the public to reduce water use by approximately ten percent.
During the Watch Stage, the demand management measures utilized during the Monitor Stage above will
increase along with a continued focus on voluntary water use reduction. The City will also increase public
outreach, implement system and operational changes, increase enforcement actions and patrols, and
City of San Luis Obispo, Municipal Code
13.07.20 – Water runoff prohibited.
A.No person shall cause any water delivered by the city water system to flow away
from property owned, occupied or controlled by such person in any gutter, ditch or
in any other manner over the surface of the ground, so as to constitute water waste
runoff.
B.“Water waste runoff” is water flowing away from property and which is caused by
excessive application(s) of water beyond reasonable or practical flow rates, water
volumes or duration of application, or due to faulty systems that have not been repaired
within seventy-two hours of written notice from the city. (Ord. 1734 § 7, 2024; Ord. 1704
§9, 2021; Ord. 1089 § 1, 1987)
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undertake other administrative actions. These program expansion and changes may include:
1.Water Demand Reduction Programs:
A.Accelerate water audit programs for all customer classes
B.Identify largest water users in each sector and contact for complimentary water audits
C.Increase water waste patrols
D.Conduct water use surveys
E.Implement rebate programs
F.Consider the use of irrigation limitations
G.Host workshops on effective irrigation practices
2.Public Outreach Programs:
A.Issue a press release following Watch Stage declaration
B.Include information in quarterly Resource Newsletter
C.Evaluate outreach effectiveness and expand outreach for non-English languages as needed
D.Update City website and create a page dedicated to information on details of WSCP Watch Stage
E.Use billing inserts to notify public of current situation and needs
F.Coordinate with regional partners on messaging and outreach
G.Increase outreach to Cuesta and Cal Poly students and at public events such as Farmers Market,
SLO Home Show, homeowners association board meetings, meetings with hospitality industry, etc.
H.Focus social media platforms on issues consistent with needed demand reductions
3. System and Operational Changes:
A.Cease any short-term water sales.
B.Reduce water usage for water main flushing and hydrant flushing
C.Reduce distribution system pressure where feasible
D.Increase leak detection, water meter testing, and water meter replacement
E.Require use of non-potable water sources for all street sweeping and hydrocleaning
F.Activate the Drought Taskforce
4.Enforcement Actions:
A.First Violation: Customer Notification and Education
Staff will notify the customer of the particular violation observed, and the demand reduction
programs currently in place. Staff will assist the customer in determining resources necessary to
comply with requirements. Examples of notification include: door tags containing educational
information, mailed letter, and/or personal phone call by staff.
B.Second Violation: Issuance of Notice of Violation
Customer will be issued a written notice of violation (NOV), notifying the customer of specific
violation, date and time the violation was observed, and consequences of subsequent violations.
C.Subsequent Violations: Customer may be issued a penalty/fine for violation.
5.Other Administrative Actions:
A.Begin drafting ordinance revisions and code changes that would go into effect in subsequent water
shortage stages.
B.Plan for the funding and implementation of specific conservation programs launched in subsequent
water shortage stages.
C.Review potential fiscal impacts of drought (i.e., increased water supply, operational, and capital
costs); and demand reductions (reduced revenue).
D.Identify and plan for the need for additional staff. In planning for additional staff, consideration
should be given to funding, available office space, vehicles, training, and other needed supplies
and support.
E.Consider need for drought surcharge to stabilize revenue.
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F.Consider deferring previously scheduled capital projects as necessary to invest in acquisition of
needed water supply sources and demand reductions.
G.Review available supplemental water supply options, such as increased use of groundwater,
utilization of potable reuse, and implementation of residential recycled water filling stations for
landscape irrigation.
4.4 Water Shortage Response Stage: Warning
When the City’s available water supply would provide less than 4.5 years of water, staff would recommend
to the City Council that they adopt a resolution to enter the Warning Stage and urge the public to reduce
water use by an additional 10 percent including mandatory conservation measures.
The water conservation measures described in the Monitor and Watch Stages above may increase during
the Warning Stage, with an increased focus on limiting outdoor water uses. System and operational
changes would remain in place. These increases and additions to programs may include:
1.Water Demand Reduction Programs:
A.Continue implementation of and possible increase of all demand reduction programs listed in Watch
Stage.
B.Limit outdoor watering to between the hours of 7:00 PM and 7:00 AM.
C.Require restaurants to only serve water upon request.
D.Restrict use of decorative2 water features and fountains.
2.Public Outreach Programs:
A.Continue implementation of and possible increase of all public outreach programs listed in Watch
Stage.
B.Issue a press release following Warning Stage declaration.
C.Target outreach to customers with large landscapes regarding irrigation restrictions.
D.Use of billing inserts, social media, postcards, and direct mail pieces to inform customers of new
requirements and prohibitions.
E.Coordinate with local business groups such as the Chamber of Commerce and landscaping
associations to help encourage conservation among commercial customers.
F.Coordinate with homeowners associations, property rental agencies, and other local groups to help
encourage conservation among residential customers.
3.Enforcement Actions (Same as previous stage)
4.Other Administrative Actions:
A.Continue implementation of and possible increase of all other administrative actions listed in Watch
Stage.
B.Begin preparing for the Alert Stage.
5.Optional Implementation of a Water Demand Offset Program:
During the Warning Stage, staff will begin updating the Water Demand Offset Program and messaging
about the program to the development community and general public. The City may consider
implementing a water demand offset program during this stage. Water demand offset programs are
designed to require new development that causes increased water demand to offset such demand
through conservation or acquisition/development of new water supplies. The goal of an offset program
is to ensure that new development does not increase current wa ter demands. It should be noted that
2 For purposes of this WSCP, decorative or recreational water features include artificially supplied ponds, lakes,
waterfalls, fountains, and similar features. These features are distinct from swimming pools and spas, as defined in
Health and Safety Code Section 115921. The City may restrict or prohibit the use of potable water for decorative water
features during shortage stages, while separately evaluating restrictions applicable to swimming pools and spas based
on public health, safety, evaporation, leakage, and other relevant considerations.
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offset programs simply expedite water efficiency measures and thus create water savings in the short
term. Depending on the nature of the offset, long-term savings may not be realized.
At the Warning Stage the City may choose to implement a “net neutral” offset program, requiring that
new demands offset usage at a rate of 1:1. Future stages of the WSCP may suggest a more aggressive,
“net positive” water demand offset program. A “net positive” water demand offset program would require
a positive offset of a project’s water demand. An example of this would be a project required to offset
its water demand at a ratio higher than 1:1, such as 2:1 or 3:1.
There are several types of offset programs in use across California and the United States. Examples
of potential offset programs are listed below.
A.Toilet replacements
B.Smart irrigation controllers
C.Submetering
D.In-lieu fees (fees are used to support new water supply projects)
E.Irrigation system retrofits
F.Waterless urinals
G.Rainwater capture
H.Recycled Water Retrofit Projects
4.5 Water Shortage Response Stage: Alert
When the City’s available water supply would provide less than four years of water,staff would recommend
to the City Council that they adopt a resolution to enter the Alert Stage and urge the public to reduce water
use by an additional 10 percent including mandatory conservation measures.
The water conservation measures described in the stages above may increase during the Alert Stage, with
an increased focus on limiting outdoor water uses. System and operational changes would remain in place.
These increases and additions to programs may include:
1.Water Demand Reduction Programs:
A.Limit outdoor watering to four days a week and only between the hours of 7:00 PM and 7:00 AM.
B.Defer landscape installations for new development or require development to install landscaping
that provides a 50 percent reduction in Maximum Applied Water Allowance (MAWA). This would
not apply to sites irrigated with recycled water.
2.Public Outreach Programs:
A.Continue implementation of and possible increase of all public outreach programs listed in previous
stages.
B.Issue a press release following Alert Stage declaration
C.Utilize water use allocation software to identify inefficient water users and make direct contact with
these properties.
3.Enforcement Actions (Same as previous stage)
4.Other Administrative Actions:
A.Continue to implement and possibly increase all other administrative actions listed in prior stages.
B.Prepare utility billing system and bill format for water allocations and reductions listed in subsequent
stages.
C.Establish appeals committee for customers who exceed allotments in subsequent stages, request
health and safety variances, or receive fines from violating water waste prohibitions.
D.Increase utility billing training and support to address additional requirements of future stages.
E.Begin preparing for Severe Stage.
5.Implementation of a Water Demand Offset Program:
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At the Alert Stage the City may implement a “net neutral” offset program or increase a previously approved
program to a “net positive” program (ex: 1.5:1 or 2:1 offset ratio). Future stages of the WSCP may suggest
a more aggressive, “net positive” water demand offset program.
4.6 Water Shortage Response Stage: Severe
When the City’s available water supply would provide less than 3.5 years of water, staff would recommend
to the City Council that they adopt a resolution to enter the Severe Stage and urge the public to reduce
water use by an additional 10 percent.
At this water shortage response stage, the City would continue implementation of demand reduction
measures previously adopted by City Council, public outreach, enforcement, and other responses and
programs described in prior stages. System and operational changes would remain in place. At the Severe
Stage, a water offset program may increase to a “net positive” program, such as 1.5:1 or 2:1 rat io.
Previous Water Demand Reduction Programs should be increased to include:
•Limit outdoor watering to three days a week and only between the hours of 7:00 PM and 7:00 AM.
During the Severe, Extreme, and Critical stages of the WSCP the City Council may adopt a Water Allotment
Program, restricting the water use on an account -by-account basis. The following allotment method may
be used:
Customer Classification Severe Stage Allotment
Single-family Residential and Multi-family
Residential
A per capita allotment allowing for indoor use and a
minimal outdoor irrigation budget. Verification of persons
per household may be requested
Commercial and Institutional Baseline allocation or allocation based on percent
reduction from normal usage
Landscape Meters Allocation based on percent reduction from normal usage
4.7 Water Shortage Response Stage: Extreme
When the City’s available water supply would provide less than three years of water, staff would
recommend to the City Council that they adopt a resolution to enter the Extreme Stage and urge the public
to reduce water use by an additional 10 percent.
At this water shortage response stage, the City would continue implementation of demand reduction
measures previously adopted by City Council, public outreach, enforcement, and other responses and
programs described in prior stages. System and operational changes would remain in place. At the Extreme
Stage, a water offset program may increase to a higher proportional “net positive” program, such as 3:1 or
4:1 ratio.
Previous Water Demand Reduction Programs should be increased to include:
•Limit outdoor watering to two days a week and only between the hours of 7:00 PM and 7:00 AM.
•Optional implementation of additional restrictions on turf and/or spray irrigation.
Customer Classification Extreme Stage Allotment
Single-family Residential and
Multi-family Residential
A per capita allotment allowing for indoor use and a reduced outdoor
irrigation budget versus the Severe Stage. Verification of persons per
household may be requested
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Commercial and Institutional Reduced baseline allocation or allocation based on percent reduction
from normal usage
Landscape Meters Reduced allocation based on percent reduction from normal usage
At this stage, due to the limited water supplies that remain, the City could consider removal of the “courtesy
notification.”
4.8 Water Shortage Response Stage: Critical
When the City’s available water supply would provide less than 2.5 years of water, staff would recommend
to the City Council that they adopt a resolution to enter the Critical Stage and urge the public to reduce
water use by an additional approximately 10 percent.
At this water shortage response stage, the City would continue implementation of demand reduction
measures adopted by City Council, public outreach, enforcement, and other responses and programs
described in prior stages. System and operational changes would remain in place. Due to the limited water
supplies that remain, the City Council would consider the cessation of new connections to the City’s water
system while the Critical State is in effect.
Previous Water Demand Reduction Programs should be increased to include:
•Cessation of irrigation for all customers, minus specific exemptions.
Customer Classification Critical Stage Allotment
Single-family Residential and
Multi-family Residential
A per capita allotment allowing for indoor water use. Irrigation not
permitted. Verification of persons per household may be requested
Commercial and Institutional Reduced baseline allocation or allocation based on percent
reduction from normal usage. Irrigation not permitted.
Landscape Meters Not permitted.
SECTION 5: COMMUNICATION, COMPLIANCE, AND ENFORCEMENT
5.1 Communication Protocols
The City will communicate water shortage conditions and response actions to customers, the public,
interested parties, and local, regional, and state agencies. Communication efforts will be scaled to the
severity of the shortage and may include but not be limited to:
A.City Council meetings and staff reports;
B.Press releases and media briefings;
C.City website updates;
D.Utility bill inserts or bill messages;
E.Direct mailers and postcards;
F.Physical postings in community facilities and areas;
G.Email notifications;
H.Social media;
I.Newsletters;
J.Community workshops;
K.Targeted outreach to organizations and support networks for disadvantaged communities;
L.Targeted outreach to high-use customers;
M.Outreach to homeowners associations, property managers, business groups, school districts,
institutional customers, and landscape professionals;
N.Coordination with regional agencies and partner organizations;
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O.Multilingual outreach materials as needed; and
P.Emergency notifications if conditions require immediate public action.
Communications will identify the current or anticipated shortage condition, the applicable WSCP stage,
required or requested customer actions, implementation dates, enforcement procedures, available
assistance, and where customers can obtain additional information.
5.2 Customer Compliance & Enforcement
The City may enforce water shortage response actions through the Municipal Code, City Council
resolutions, ordinances, administrative procedures, or other applicable legal authorities. Enforcement may
increase in intensity as shortage conditions become mor e severe or as repeated violations occur. Where
feasible, the City will prioritize education and communication with residents to encourage compliance before
relying on penalties or fines.
Potential enforcement actions include:
A.Courtesy notices;
B.Written warnings;
C.Notices of violation;
D.Administrative citations or penalties;
E.Installation of flow restrictors, where legally authorized and appropriate;
F.Termination of service for severe or repeated violations, where legally authorized and necessary;
G.Referral for additional enforcement; and
H.Other remedies authorized by law.
The City may use monthly meter reads, Advanced Metering Infrastructure (AMI) data when available,
customer reports, staff observations, water waste patrols, and billing system data to monitor compliance
with shortage response actions.
5.3 Legal Authorities
The City’s legal authorities for implementing and enforcing this WSCP may include, but are not limited to:
A.California Water Code Sections 350 et seq. related to water shortage emergencies;
B.California Water Code Section 10632 and related UWMP Act provisions;
C.California Water Code Section 10632.1 related to annual water supply and demand assessments;
D.California Water Code Chapter 3.3 related to excessive residential water use during drought;
E.San Luis Obispo Municipal Code Chapter 13.07, Water Conservation;
F.City Council resolutions declaring shortage stages or authorizing response actions;
G.City Council ordinances establishing mandatory restrictions, penalties, rates, surcharges, or other
measures;
H.Water service rules, regulations, and customer service requirements;
I.Emergency powers available under local or state law; and
J.Contractual authorities, where applicable.
When required by applicable conditions, the City Council shall declare a water shortage emergency in
accordance with California Water Code Chapter 3, Section 350. The City shall coordinate with the County
of San Luis Obispo and any other applicable local agency regarding the possible proclamation of a local
emergency, as defined in Government Code Section 8558.
SECTION 6: WATER BUDGETS, EXEMPTIONS, AND APPEALS
6.1 Water Budgets & Allotments
During advanced shortage stages, the City may implement water budgets or water allotments to reduce
demand and allocate available supplies in a manner that protects public health, safety, sanitation, fire
protection, and other essential uses. Water budgets and allotments may be implemented by customer class,
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individual account, property type, historical use, irrigated area, or another method approved by the City
Council.
Water budgets or allotments may be based on one or more of the following:
A.Customer class;
B.Historical water use;
C.Household size;
D.Irrigated landscape area;
E.Aerial imagery or parcel data;
F.Business or institutional function;
G.Health and safety needs;
H.Fire protection requirements;
I.Functional landscape needs;
J.Recycled water availability;
K.Seasonal demand patterns; and
L.Other relevant and legally supportable criteria.
The City may use aerial imagery, parcel data, customer account information, water meter data, AMI data
when available, or other available information to establish water budgets or allotments. Water budgets may
be adjusted by the City,as needed,to reflect updated information, customer appeals, approved exemptions,
corrected account information, or changing shortage conditions.
6.2 Exemptions & Adjustments
The City may allow limited exemptions or adjustments from specific water shortage response actions when
necessary to protect public health, safety, sanitation, fire protection, essential community functions, or long -
term community resources. Exemptions and adjustments are intended to address unique circumstances
and do not exempt any customer from the City’s general water waste prohibitions, including prohibitions on
water waste caused by substandard, leaky or faulty fixtures or devices, irrigation runoff, or other avoidable
waste of water.
Requests for exemptions from water use restrictions shall be processed in accordance with San Luis
Obispo Municipal Code Section 13.07.100 and any applicable rules and procedures adopted by City
Council resolution. Section 13.07.100 establishes the Water Conservation Adjustment Board and
authorizes the Board to grant exceptions for uses of water otherwise prohibited by Section 13.07.070. The
Board consists of the directors of the City’s Finance, Utilities,3 and Community Development Departments,
or their designees.
Exemptions may be limited in duration, conditioned on corrective actions, or subject to monitoring and
reporting requirements. The City may revoke or modify an exemption if conditions change, if the basis for
the exemption no longer applies, or if the customer fails to comply with applicable conditions.
Potential exemption or adjustment categories may include:
Recycled Water Use:
Sites using recycled water for irrigation or other approved non -potable uses may be exempt from potable
water irrigation restrictions because these uses do not rely on the City’s potable water supply. Recycled
water use remains subject to applicable recycled water regulations, permits, site requirements, and
operational limitations. Recycled water exemptions do not authorize wasteful use, runoff, or use
inconsistent with recycled water rules or permit conditions.
Public Parks, Schools, and Community Recreation Areas:
The City may allow limited irrigation adjustments for public parks, schools, athletic fields, and other
community recreation areas when necessary to protect public health and safety, preserve functional
recreational areas, or avoid hazardous conditions. Th ese adjustments may be limited to specific facilities,
3 Recognized as the Director of the Public Works and Utilities Department.
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irrigation schedules, turf renovation periods, or other conditions established by the City. Such adjustments
would apply only to the specific shortage measures identified by the City and would not exempt the facility
from water waste prohibitions or leak repair requirements.
Tree Preservation:
The City may allow limited irrigation necessary to preserve established trees, recognizing that trees provide
long-term environmental, community, shade, habitat, stormwater, and economic benefits. Tree irrigation
adjustments may be limited to hand watering , drip irrigation, soaker hoses, or other efficient methods
approved by the City. This exemption is intended to preserve trees and does not authorize turf irrigation,
runoff, overspray, or other wasteful water use.
Health, Safety, and Essential Uses:
Hospitals, healthcare facilities, care facilities, schools, food service establishments, critical businesses, and
other customers with water needs related to public health, safety, sanitation, or essential operations may
request an exemption or adjustment on a case-by-case basis. The Public Works and Utilities Director or
designee may approve an exemption when the customer demonstrates that strict application of a shortage
requirement would create a health, safety, sanitation, or essential service concern.
Other Case-by-Case Adjustments:
The City may consider other case-by-case exemptions or adjustments based on unique circumstances,
including medical needs, fire protection needs, establishment of newly installed drought -tolerant
landscaping if allowed by the applicable shortage stage, doc umented billing or classification errors, or other
circumstances determined by the Public Works and Utilities Director or designee to be consistent with the
purpose of the WSCP.
6.3 Appeals
Appeals related to exemption requests, water use restrictions, water budgets, allotments, penalties, or
enforcement actions shall be processed in accordance with San Luis Obispo Municipal Code Section
13.07.100 and any applicable City Council-adopted rules or procedures.
Section 13.07.100 establishes the Water Conservation Adjustment Board for the purpose of appealing
water conservation-related regulations and associated fines and penalties. The Board consists of the
directors of the City’s Finance, Utilities,4 and Community Development Departments, or their designees.
Appeal procedures will be communicated to customers when water budgets, allotments, penalties, or other
appealable requirements are implemented. Appeals may consider the customer’s circumstances, water use
history, customer classification, health and safety needs, documented leaks or repairs, and consistency
with the City’s adopted shortage response actions.
Filing an appeal does not relieve a customer from the obligation to comply with applicable water waste
prohibitions, repair leaks, prevent runoff, or comply with emergency restrictions necessary to protect public
health, safety, sanitation, or fire protection, unless otherwise authorized by the City.
SECTION 7: REVENUE AND EXPENDITURE IMPACTS
Implementation of the WSCP may affect City revenues and expenditures. Water conservation and demand
reduction may reduce water sales revenue, while shortage response actions may increase costs related to
staffing, public outreach, enforcement, customer service, billing system changes, emergency repairs,
supplemental supply development, and operational adjustments.
The City may evaluate revenue and expenditure impacts during each shortage stage and may recommend
financial response measures to the City Council as needed. Potential financial measures may include use
of reserves, budget adjustments, deferral or reprioritization of capital projects, temporary drought rates or
surcharges, increased penalties for water waste or violations, grants, loans, emergency funding, cost
4 Recognized as the Director of the Public Works and Utilities Department.
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recovery for emergency response actions, adjustments to conservation program funding, or other financial
tools authorized by law.
During the 2012–2015 drought, the City utilized a drought surcharge to help address revenue shortfalls
related to mandatory conservation measures. Any future drought surcharge, rate adjustment, or other
financial measure would be evaluated based on actual shortage conditions, projected revenue impacts,
implementation costs, legal requirements such as Proposition 218, and City Council direction.
During a declared water shortage, the City will monitor monthly water consumption, revenue, expenditures,
enforcement activity, outreach needs, and program implementation costs. Staff may recommend program
refinements or financial actions to the City Council as conditions evolve.
As required by California Water Code Section 10632(a)(8)(C), the City has considered the potential cost of
compliance with Chapter 3.3 of Division 1, commencing with Section 365, related to excessive residential
water use during drought. Potential compliance-related costs that the City may incur include billing system
programming, printing and delivery of customer notices, tracking and reporting excessive use, appeal
processing, enforcement documentation, staff time, legal review, and customer service suppo rt. The
amount of these costs would depend on the shortage stage, the requirements triggered, the number of
affected accounts, and the enforcement approach approved by the City Council.
SECTION 8: MONITORING, REPORTING, AND REFINEMENT
PROCEDURES
The City reads water meters monthly to collect water consumption data for billing, tracking, analysis, and
state reporting.Collection of monthly water use data allows the City to evaluate demand trends, identify
potential changes in customer behavior, monitor compliance, and determine whether projected demands
remain consistent with actual use.
Monitoring and reporting are fundamental to water shortage planning and implementation. During shortage
conditions, the City may monitor reservoir storage, source availability, precipitation and hydrologic
conditions, water treatment and conveyance conditions, recycled water availability, groundwater project
status and production, customer demand by class, total potable and non -potable water use, water loss,
compliance with restrictions, enforcement activity, public outreach effectiveness, revenue and expen diture
impacts, and Water Projection Model results.
The City may update the Water Projection Model as conditions change and may reevaluate whether the
current WSCP stage remains appropriate. Staff may recommend that the City Council maintain, intensify,
reduce, or terminate shortage response actions based on updated supply conditions, customer demand,
compliance levels, weather, infrastructure status, or other relevant factors.
Each year, in compliance with California State regulations, the City will compile a Water Supply and
Demand Assessment to determine if supplies are sufficient to meet demands in the upcoming year. Staff
will provide this information to the City Council each year, generally in May or June, allowing for the
information to be submitted to DWR by July 1, as required by the California Water Code.
SECTION 9: CATASTROPHIC WATER SUPPLY INTERRUPTION
Catastrophic water supply interruptions may occur with little or no warning and may require immediate
action to protect public health, safety, sanitation, and fire protection. Potential causes include earthquake,
wildfire, flooding, major pipeline failure, water quality contamination, regional power outage, treatment plant
failure, cyberattack, dam or reservoir emergency, or other events that may affect the City’s ability to access,
treat, convey, or distribute water.
The shortage levels established in this WSCP apply to catastrophic interruptions of water supplies, including
regional power outages, earthquakes, and other emergency events. Because emergency conditions can
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differ significantly from drought-related shortages, the City may implement targeted emergency actions,
operational changes, public notifications, or temporary restrictions that differ from the drought response
measures listed in this WSCP, while using the shortage levels as an organizing framework when
appropriate.
9.1 Seismic Risk and Hazard Mitigation Planning
The City participates in regional hazard mitigation planning through the San Luis Obispo County Multi -
Jurisdictional Hazard Mitigation Plan (MJHMP). The MJHMP evaluates hazards, vulnerabilities, and
mitigation strategies associated with natural and human-caused disasters, including seismic risk. The City
incorporates the MJHMP by reference in the UWMP to support compliance with California Water Code
Section 10632.5.
The City’s water system benefits from multiple water supply sources, interconnected transmission lines,
emergency storage, backup power capabilities, mutual aid coordination, and emergency response
procedures. These measures support the City’s ability to prepare for, respond to, and recover from seismic
events and other emergencies that could affect water service.
9.2 Emergency Response and Mutual Aid
The City maintains emergency response procedures and coordinates with local, regional, and state partners
during emergency conditions. The City may use emergency response plans, emergency operations
procedures, mutual aid agreements, and coordination with public safety agencies to respond to catastrophic
interruptions.
The City is a member of the Water Agency Response Network (WARN), a statewide mutual aid network
that supports water and wastewater agencies during emergencies. The City may also coordinate with
regional partners, including agencies associated with Whale R ock Reservoir, Nacimiento Reservoir, the
County of San Luis Obispo, neighboring cities, and other water agencies.
The City may use onsite and portable generators to support water treatment, pumping, storage, and
distribution functions during power outages. The City may also implement operational changes, emergency
repairs, temporary demand restrictions, interconnections, emergency procurement, public notifications,
bottled water distribution, or other emergency actions as needed.
As part of the City’s planned groundwater extraction project, the City has considered emergency response
functionality in the siting and design of the two new groundwater wells. In addition to serving as future
supplemental potable water supply sources, the wells are located in an area that provides relative ly
convenient vehicle access and is proximate to existing City facilities.
During a catastrophic event or severe emergency, such as a major earthquake, wildfire, extended power
outage, large transmission main failure, or other event that interrupts water service or otherwise limits the
City’s ability to convey or distribute water through the normal system, the groundwater well sites could
provide an accessible location for emergency water distribution. Depending on the nature of the emergency,
regulatory requirements, treatment system status, water quality conditions, staffing, traffic control, and
public safety considerations, the City may use these sites to support filling of emergency water containers,
water tenders, or other approved distribution methods.
The ability to use the groundwater well sites as emergency filling stations would provide an additional layer
of resiliency by creating a potential local water access point outside of the normal distribution system. This
capability would not replace the City’s broader emergency response procedures, mutual aid coordination,
backup power planning, or water distribution system restoration efforts, but it would provide another tool to
support emergency water access during catastrophic supply interruptions.
9.3 Emergency Response Actions
Potential actions during a catastrophic water supply interruption may include:
A.Activate emergency operations procedures;
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B.Notify City leadership, emergency management, and affected agencies;
C.Evaluate system damage and operational status;
D.Prioritize water for public health, safety, sanitation, and fire protection;
E.Issue public notifications, advisories, or emergency instructions;
F.Implement temporary water use restrictions;
G.Isolate damaged facilities or pipelines;
H.Deploy backup power or portable generators;
I.Coordinate emergency repairs;
J.Request mutual aid through WARN or other agreements;
K.Coordinate with public health and regulatory agencies;
L.Provide temporary water supplies where feasible;
M.Use available alternative sources, if operationally and legally feasible;
N.Monitor water quality and system pressure;
O.Update the City Council and public; and
P.Transition to appropriate WSCP stages if the interruption results in an ongoing shortage.
SECTION 10: ADOPTION, SUBMITTAL, AND AVAILABILITY
This WSCP is prepared and adopted in coordination with the City’s 2025 UWMP and is included as an
appendix to the UWMP. The WSCP may be amended separately from the UWMP if necessary to address
changing conditions, regulatory requirements, operational needs, emergency response proce dures, or City
policy direction, provided that applicable notice, public hearing, adoption, and submittal requirements are
satisfied.
Following adoption, and no later than July 1, 2026, the City will submit the adopted WSCP, together with
the 2025 UWMP as applicable, to DWR, the California State Library, and applicable cities and counties
within which the City provides water supplies. In any event, the City will complete required post-adoption
submittals and make the adopted WSCP available to customers, the public, and applicable cities and
counties no later than 30 days after adoption. The adopted WSCP will be made available through the City’s
website, and copies will be available at the City’s Utilities Administration Office at 879 Morro Street in San
Luis Obispo.
If the City amends the WSCP in the future, the City will follow applicable public review, hearing, adoption,
and submittal requirements.
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APPENDIX I: STANDARDIZED TABLES
Submittal Table 8-1: Cross-reference for Standard vs
Supplier Shortage Levels
Water Code Section 10632(a)(3)(B)
Check the box if the Supplier uses the
Standard six levels of water shortage.
Proceed to the next table.
Standard
Shortage
Levels
Percent
Shortage
Range
Suppliers
Shortage
Levels
Percent
Shortage
Range
1 Up to 10% Watch Stage Up to 10%
2 Up to 20%Warning
Stage Up to 20%
3 Up to 30% Alert Stage Up to 30%
4 Up to 40%Severe Stage Up to 40%
5 Up to 50% Extreme
Stage Up to 50%
6 >50%Critical
Stage >50%
NOTES: N/A
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Submittal Table 8-2 Retail: Supply Augmentation and Other Actions
Water Code Section 10632(a)(4)(A),(C) and (E)
Yes Is the Supplier completing this table using the standard six levels? (yes/no)
Shortage
Level
Supply Augmentation Methods
and Other Actions by Water
Supplier
Drop down list
These are the only categories that will
be accepted by the WUEdata online
submittal tool
How much is this going to reduce the
shortage gap? Additional
Explanation or
Reference
(OPTIONAL)
Volume or
Percentage
Drop down
Shortage Gap
Reduction Value
(May be a range)
(AF)
Add additional rows as needed
1 - Watch Percentage 0%
2 - Warning Percentage 0%
3 - Alert Percentage 0%
4 - Severe Percentage 0%
5 - Extreme Percentage 0%
6 - Critical Percentage 0%
DWR NOTES: Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in
Submittal Table 2-3.
NOTES: The City of San Luis Obispo does not have any identified supply augmentation projects that have an
implementation dependent upon Water Shortage Contingency Plan Stage.
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Submittal Table 8-3 Retail: Demand Reduction Actions
Water Code Section 10632(a)(4)(B) and (E)
Yes Is the Supplier completing this table using the standard six levels? (yes/no)
Shortage
Level
Demand Reduction Actions
Drop down list
These are the only categories that will
be accepted by the WUE data online
submittal tool. Select those that apply.
How much is this going to
reduce the shortage gap? Additional
Explanation or
Reference
(OPTIONAL)
Penalty,
Charge, or
Other
Enforcement?
For Retail
Suppliers Only
Drop Down List
Volume or
Percentage
Drop down
Shortage Gap
Reduction
Value
(May be a range)
(AF)
Add additional rows as needed
1 Expand Public Information
Campaign Percentage 5.00% No
1 Offer Water Use Surveys Percentage 1.00% No
1 Provide Rebates on Plumbing
Fixtures and Devices Percentage 0.50% No
1 Increase Water Waste Patrols Percentage 1.00% Yes
1 Provide Rebates for Landscape
Irrigation Efficiency Percentage 0.50% No
1 Decrease Line Flushing Percentage 1.00% No
1 Reduce System Water Loss Percentage 1.00% No
2 Expand Public Information
Campaign Percentage 5.00% No
2 Increase Water Waste Patrols Percentage 3.00% Yes
2 Landscape - Limit landscape
irrigation to specific times Percentage 1.50% Yes
2 CII - Restaurants may only serve
water upon request Percentage 0.25% Yes
2
Water Features - Restrict water use
for decorative water features, such
as fountains
Percentage 0.25% Yes
3 Moratorium or Net Zero Demand
Increase on New Connections Percentage 0.25%
Initiate new
connection
offset program
Yes
3 Expand Public Information
Campaign Percentage 5.75% No
3 Increase Water Waste Patrols Percentage 3.00% Yes
3 Landscape - Limit landscape
irrigation to specific days Percentage 1.00% 4 Days Per
Week Yes
4 Other Percentage 8.75%
Initiate Water
Allotment
Program
Yes
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4 Landscape - Limit landscape
irrigation to specific days Percentage 1.00% Three Days Per
Week Yes
4 Moratorium or Net Zero Demand
Increase on New Connections Percentage 0.25%
Intensify ratio
of new
connection
offset program
Yes
5 Landscape - Limit landscape
irrigation to specific days Percentage 1.00% Two Days Per
Week Yes
5 Other Percentage 9.00%
Increase Water
Allotment
Program
Severity
Yes
6 Landscape - Prohibit all landscape
irrigation Percentage 5.00% Yes
6 Other Percentage 5.00%
Increase Water
Allotment
Program
Severity
Yes
6 Moratorium or Net Zero Demand
Increase on New Connections Percentage 0%
Cessation of
New
Connections
Yes
DWR NOTES: Units of measure (AF, CCF, MG) must remain consistent throughout the UWMP as reported in
Submittal Table 2-3.
NOTES:
1.During Stage 6, Cessation of New Connections is represented as resulting in a 0% decrease in water demand,
as this cessation will not reduce current water use, rather it aims to reduce future water demand attributed
to new development.
2.Demand reduction actions are intended to be cumulative. Actions implemented at a lower shortage level are
assumed to remain in effect at higher shortage levels unless modified, suspended, or replaced by City
Council action.
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APPENDIX II: PUBLIC HEARING NOTICE
Public hearing notices for the City’s 2025 Water Shortage Contingency Plan will be included in this appendix once they
have been published.
At the time of the preparation of the Draft Water Shortage Contingency Plan, all public hearing notices had not yet been
published. The City will publish notice of the public hearing in accordance with applicable requirements prior to adoption
of the Water Shortage Contingency Plan. Following publication, copies of the public hearing notices, including the date
of publication and noticing information, will be added to this appendix.
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APPENDIX III: ADOPTION RESOLUTION
A copy of the signed WSCP adoption resolution will be provided after the June 16, 2026 City Council
meeting.
RESOLUTION NO. _____ (2026 SERIES)
A RESOLUTION OF THE CITY COUNCIL OF THE CITY OF SAN LUIS
OBISPO, CALIFORNIA, ADOPTING THE 2025 WATER SHORTAGE
CONTINGENCY PLAN
WHEREAS, the California Legislature enacted Assembly Bill 797 during the 1983-1984 Regular
Session, and as amended subsequently, which mandates that every supplier providing water for municipal
purposes to more than 3,000 customers or supplying more than 3,000 acre-feet of water annually, prepare
an Urban Water Management Plan and separate Water Shortage Contingency Plan; and
WHEREAS, the City is an urban water supplier providing more than 3,000 acre-feet water annually
to approximately 17,000 customers; and
WHEREAS, the 2025 Water Shortage Contingency Plan includes planned response actions during
six water shortage levels to manage and mitigate potential water supply shortages; and
WHEREAS, the 2025 Water Shortage Contingency Plan includes the written process the City will
use each year to determine its water supply reliability; and
WHEREAS, the 2025 Water Shortage Contingency Plan must be adopted, after public review and
hearing, and submitted to the California Department of Water Resources by July 1, 2026; and
WHEREAS, the City has therefore prepared for public review a draft 2025 Water Shortage
Contingency Plan, and a properly noticed public hearing regarding the Plan was held by the City Council
on June 16, 2026.
NOW, THEREFORE, BE IT RESOLVED by the Council of the City of San Luis Obispo as follows:
SECTION 1. Adoption of the 2025 Water Shortage Contingency Plan. The 2025 Water Shortage
Contingency Plan for the City of San Luis Obispo, consisting of text, tables, and appendices presented to
the City Council on June 16, 2026, on file at the City Clerk’s Office, is hereby adopted.
SECTION 2. The Public Works and Utilities Director or Assistant Utilities Director are hereby
directed to distribute the 2025 Water Shortage Contingency Plan to the California Department of Water
Resources, the California State Library, and the County of San Luis Obispo, and make available for public
review as prescribed by state law.
SECTION 3. California Environmental Quality Act. The adoption of the City’s 2025 Water
Shortage Contingency Plan is hereby determined to be statutorily exempt from the requirements of the
California Environmental Quality Act (CEQA) pursuant to Section 10652 of the Water Code.
Upon motion of Council Member ___________, seconded by Council Member ___________, and
on the following roll call vote:
AYES:
NOES:
ABSENT:
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The foregoing resolution was adopted this _____ day of _______________ 20 26.
___________________________
Mayor Erica A. Stewart
ATTEST:
______________________
Teresa Purrington
City Clerk
APPROVED AS TO FORM:
______________________
J. Christine Dietrick
City Attorney
IN WITNESS WHEREOF, I have hereunto set my hand and affixed the official seal of the City of San Luis
Obispo, California, on ______________________.
___________________________
Teresa Purrington
City Clerk
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