HomeMy WebLinkAbout04-04-2017 CAR - Study Session Regarding Inflow and Infiltration Reduction and Private Sewer Lateral ProgramMeeting Date: 4/4/2017
FROM: Carrie Mattingly, Utilities Director
Prepared By: David Hix, Utilities Deputy Director, Wastewater
Jennifer Metz, Utilities Projects Manager
Bud Nance, Wastewater Collection System Supervisor
SUBJECT: STUDY SESSION REGARDING INFLOW AND INFILTRATION
REDUCTION AND PRIVATE SEWER LATERAL PROGRAM
RECOMMENDATION
Receive a presentation on inflow and infiltration reduction, including a Private Sewer Lateral
Program, in a study session and provide feedback on reduction approaches.
DISCUSSION
Report-In Brief
Inflow and infiltration (I/I) results from rainwater entering structurally deficient private sewer
laterals, public sewer mains, and illegal connections. I/I flows in the City of San Luis Obispo are
significant and impact all users of the wastewater system in one way or another. Effective I/I
reduction is necessary to eliminate overflows and pipe surcharging, reduce the amount of I/I flow
to the Water Resource Recovery Facility (WRRF), and free up pipe capacity to serve planned
infill development. Achieving success will require both public and private investment.
In July 2016, the City signed a settlement agreement with California River Watch related to
alleged Clean Water Act violations. In alignment with the settlement agreement, this study
session will be introducing programs for consideration, such as private sewer lateral inspections
and offset programs. Staff is seeking direction on the scope of the program before finalizing it
for Council approval.
Background
Since October 2016 when the City
Council first received a presentation on
wastewater collection system capacity
constraints created by I/I (Attachment A),
there has been a lot of rain. Flows at the
WRRF have been extraordinary and
several overflows happened in the
collection system (see Table 1). For short
periods of time during wet weather
events, flows spike, as shown in Figure 1.
Table 1: 2016 and 2017 Sanitary Sewer
Overflows related to Inflow and Infiltration
Overflow Date Overflow Location
Overflow
Quantity
in gallons)
January 31, 2016 81 Broad 13,500
January 20, 2017 Broad and Murray 31,500
January 22, 2017 93 Broad 36,000
February 17, 2017 Ramona 3,500
February 21, 2017 Ramona 3,000
TOTAL: 87,500
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Figure 1. Water Resource Recovery Facility, Average and Peak Flows
NOTE: Flows in Figure 1 are in million gallons per day (MGD).
These spikes define needed capacity improvements in the collection system and at the WRRF.
The spikes also show the rapid movement of I/I entering poor condition pipes and creating
overflows and treatment problems. In a perfect system, there would be no difference in capacity
during wet weather events as the system would be entirely “closed loop.” A truly perfect system
is not practically realistic however, efforts can be made to minimize the amount of I/I entering
the City’s wastewater system.
Sanitary sewer overflows are a public health risk
and can result in NPDES (National Pollutant
Discharge Elimination System) Permit violations,
fines from the Central Coast Water Board, beach
closures by the San Luis Obispo County Public
Health Department, Clean Water Act third party
lawsuits, or a long-term enforcement agreement
referred to as a consent decree.
The City completed its Wastewater Collection
System Infrastructure Renewal Strategy
Renewal Strategy) in 2016. The Renewal
Strategy called attention to the fact that more
than 18 miles (13 percent) of the collection
system, along with most of the associated private
Sewage spills reaching San Luis Obispo Creek
may result in beach closures due to environmental
health concerns.
Source: KSBY.com January 2017
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sewer laterals connecting to those pipes, is at
least 75 years old. Private sewer laterals, those
pipes that run from the building all the way to
the publicly owned main sewer lines in the
street, are the responsibility of the property
owner, as shown in Figure 2. There are 172
miles of private sewer laterals that are rarely
inspected prior to failure. Private sewer laterals
are not the only source of I/I; however, with
more miles of private sewer laterals than public
sewer mains, holistically reducing I/I cannot be
as effective unless leaky private sewer laterals
are addressed in tandem with the efforts being
made on the public sewer mains.
Figure 2. Private Sewer Lateral Responsibility
I/I Reduction Goals
Reducing I/I has many benefits to the City including preventing overflows, reducing community
health risks and meeting required regulatory conditions. Some additional goals of I/I reduction
are:
1. Reclaim lost pipeline capacity in constrained areas that would allow new infill
development. Every gallon per minute of I/I reduces serviceable population by
approximately eight households.
2. Defer and/or reduce costly sewer main replacements needed to provide capacity for
I/I.
3. Incrementally reduce the treatment capacity at the WRRF resulting in cost savings on
everything from process equipment replacement to chemicals and energy (potentially
millions of dollars) and operating costs.
4. Reduce greenhouse gas emissions created by pumping, chemicals and treatment
needed for I/I.
Table 2: Public and Private Sewer
Infrastructure
Public Sewer Mains
City responsibility)
136 miles
Private Sewer Laterals
property owner responsibility)
172 miles*
Total: 308 miles
Note: The total miles of private sewer laterals is
estimated based on 14,000 laterals at an average of
65 feet per lateral.
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California River Watch Settlement Agreement
In July 2016, the City entered into a settlement agreement with California River Watch regarding
alleged Clean Water Act violations. The City agreed to further consider two Supplemental
Environment Programs intended to secure significant benefits to the local environment. The
following programs are excerpted from that agreement:
Lateral Inspection and Repair Program: Within one (1) year from the Effective Date
of this Agreement, the City staff shall recommend to the City Council an ordinance
establishing a program for the inspection, repair, and/or replacement of private
sewer laterals. The program proposed will use the following events as a basis or
trigger” for inspection, repair, and/or replacement:
1. Transfer of ownership of the property if no inspection or replacement of the
sewer lateral occurred within twenty (20) years prior to the transfer;
2. If two (2) or more sanitary sewer overflows are caused by the same private
sewer lateral within the immediate past two (2) years; or
3. Where the application for a building permit indicated the expected addition of
flow through the private lateral (e.g. addition of bathrooms, bedrooms,
addition living space).
Voluntary Private Lateral Replacement Rebate Program: The City staff shall
recommend a Voluntary Private Lateral Replacement Rebate Program. For three (3)
years from establishment, the Program will provide, on a first come, first served
basis, one thousand ($1,000) dollars toward the total replacement costs of a
residential private lateral, not to exceed a total of fifty thousand ($50,000) dollars
annually.
The settlement agreement with California River Watch does not mandate that the City adopt
either of these programs; but it does mandate that the City Council consider an ordinance to
establish such programs.
Ordinance to Establish a Private Sewer Lateral Program
To comply with the settlement agreement, staff will be bringing forward an ordinance for the
City Council to consider establishing a Private Sewer Lateral Program. The ordinance will
describe the three triggering events requiring a sewer lateral inspection (for laterals greater than
20 years old):
1. Transfer of Ownership;
2. Private Sewer Overflow; and
3. Application for a Building Permit.
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Some programs to address these triggering events are described at a high level below.
Transfer of Ownership
A seller of the real estate property would be required to demonstrate that their lateral does not
contribute I/I to the City at the time of property sale/property transfer. To demonstrate to the City
that a seller’s lateral will not contribute I/I the seller would provide either:
Evidence that the sewer lateral complies with existing City standards or was installed
after January 1, 1997; or
A copy of a plumbing permit for 100 percent installation or replacement of the lateral
after January 1, 1997.
The January 1, 1997 date is proposed to comply with the 20-year timeframe in the Settlement
Agreement. This timeframe corresponds to changes in City Engineering Standards that required
the use of plastic pipe fused with heat or glue, which prevents I/I getting into the pipe.
If the seller does not have the necessary documentation, they would have their sewer lateral
inspected. A California state licensed plumbing contractor can perform the inspection. If no
defects are found in the sewer lateral pipe, the City would confirm, provide the seller with
confirmation and store the information in the City’s data base. If repair or replacement are
necessary, the seller would complete them in accordance with a timeline, and then receive
confirmation from the City before the property could be sold.
Private Sewer Overflows
A property owner with two sewer overflows over two years would be required to demonstrate
that their lateral does not contribute to I/I. Multiple overflows suggest that the lateral is in poor
condition and may be contributing to I/I. Staff would work with and educate the owner about the
program. Timelines for repair and/or replacement of the lateral will be determined while working
with the owner.
Application for Building Permit
A property owner would be required to demonstrate that their lateral does not contribute I/I to the
City before receiving a building permit for the following:
Remodeling involving adding bedroom(s), plumbing fixtures including, but not
limited to, drains, sinks, toilets or faucets;
A change in water service is requested (increase in meter size or adding a second
meter);
To demonstrate that their lateral does not contribute to I/I the same process as the transfer of
ownership would be used. The timeline for repair or replacement, if required, would be
determined as part of the building permit process.
Based on annual property sales and permit activity, staff estimates that the lateral program would
result in modifications and/or repairs to approximately 100-250 private sewer laterals to bring
them into conformance with City standards. It is estimated 10,000 existing private sewer laterals
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do not meet current City standards or are older than 20 years.
Sewer Lateral Repair or Replacement Requirements
While repair and replacement criteria is still being developed; below are some conditions that
will likely be considered to determine if a lateral does not contribute to I/I.
Private sewer lateral does not meet current City standards, but is water tight. No
corrective measures are required.
Private sewer lateral must be repaired, rather than replaced, to be water tight due to
isolated cracks, root intrusion, or similar minor pipe failure.
Private sewer lateral must be replaced to be water tight due to extensive cracks, root
intrusion, or similar major pipe failure.
Voluntary Private Lateral Replacement Rebate Program Approach
Consistent with the settlement agreement, the City will be proposing a voluntary private lateral
replacement rebate program as part of the 2017-19 Financial Plan. Under this program, the City
could offer the rebate Citywide, focus on rebates to capacity constrained areas, and/or offer
larger rebates in capacity constrained areas. Funding collected from the offset program could be
used to increase rebates local to the project or in capacity constrained areas to encourage lateral
replacement. Rebates would be made available to those required to repair or replace sewer
laterals as well as anyone voluntarily replacing one. Through staff’s outreach efforts rebates have
been identified by stakeholders as critical to a successful lateral program. Should Council
provide direction to proceed with a program, the 2017-2019 budget would include funding and
staff would return with future guidelines for the use of the funds for any voluntary program.
Other Non-Settlement Related I/I Programs
Accelerated I/I Reduction Approach
The Private Sewer Lateral Program will incrementally help the City make progress toward I/I
reduction. However, unacceptable I/I will continue for many years. As an estimated 10,000
private laterals may require inspection, repair or replacement this approach would accelerate
progress toward the I/I reduction goals. The cost to have a plumbing contractor inspect a private
sewer lateral is approximately $250. The cost for full replacement of a lateral, including City
permit fees described below, is approximately $8,000.
To increase sewer lateral inspection, repair, and replacement beyond what can be achieved
through change in ownership and permit activity per the programs discussed above, the City
could develop a proactive program designed to achieve an accelerated reduction of inflow and
infiltration.
Currently, San Luis Obispo Municipal Code § 13.08.390.D requires all sewer laterals to be “…in
a safe and sanitary condition; and all devices or safeguards which are required for the operation
thereof shall be maintained in a good working order.” However, absent a program such as those
discussed above, knowledge of the condition of a lateral is usually unknown unless it fails.
Staff could develop an ordinance for City Council consideration that a certain set of sewer
laterals (i.e. all houses constructed before January 1, 1997, and/or all houses in a capacity
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constrained area of the City, etc.) be inspected to determine if the lateral contributes I/I. Based
on set criteria, repairs and/or replacement would need to be made within an established
timeframe. The City has had success with similar programs, such as the Unreinforced Masonry
Hazard Mitigation Program, where deadlines for inspection and repairs were identified. An
accelerated I/I reduction program would likely require, at a minimum, additional funding for
rebates should Council desire to offer them.
Wastewater Flow Development Offset Program
Wet weather capacity constraints were identified in the wastewater collection system in the
Renewal Strategy presented to the City Council on January 19, 2016. The Renewal Strategy
estimated the total cost to fix this problem at $30 million. Development projects and inquiries are
taking place in areas that are the most impacted by I/I and staff has required wastewater flow
offsets as a condition of development to allow the projects to move forward.
Although I/I is widespread throughout the City, Attachment C shows areas most impacted by
existing capacity deficiencies in the wastewater collection system during wet weather. The areas
include:
Laguna Lake,
North and south of Foothill west of Santa Rosa Road,
North of South Street south of the downtown core,
South of Pismo Street east of Santa Barbara Road and north of the Union Pacific
Railroad tracks.
These areas of the collection system experience “surcharging,” a condition where the sewer pipe
is so full the wastewater flow starts backing up in the pipe and sometimes up into the manholes.
To allow development to proceed in these areas, staff has utilized an offset mitigation strategy
whereby private sewer laterals can be replaced to eliminate I/I and offset the new development’s
additional wastewater flows.
Staff will return and recommend a Wastewater Flow Offset Program to create wet weather
capacity in a pipeline by rehabilitating private sewer laterals in the affected area. The wastewater
flow offset would be required to achieve a flow rate reduction greater than the incremental
increase generated by development. This offset program could be extended to mitigate I/I
citywide anywhere wet weather flows cause problems in the system.
Permit Cost Recovery
The City’s permit cost for replacement of a private sewer lateral is about $1,500. These fees
include the encroachment fee for working in the street, the plumbing permit for inspection of the
lateral installation on private property and the installation of the “wye”, which connects the
private lateral to the public main. Stakeholders have expressed support for a reduced fee and
believe it would contribute to the success of the Private Sewer Lateral Program. These fees have
been recently revised in the updated costs of services study and cover the costs of general and
sewer fund services. The City could consider less than 100 percent cost recovery for permit fees
associated with private sewer lateral replacement. Because of the net increase in lateral repairs
and/or replacements and the collection of the related fees, anything less than 100 percent
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recovery could at a minimum, have a neutral fiscal impact on the wastewater fund.
Outreach Efforts and Implementation
In addition to this Study Session, staff has engaged the development community to discuss the
scope of capacity constraints in the collection system and the Private Sewer Lateral Program at
the Developer’s Roundtable. Staff has also met with Realtors related to the inspection
requirement. Discussions with local plumbers about a lateral program and its important aspects
are ongoing. Consideration of the Private Sewer Lateral Program is on the City Council’s agenda
for May 16, 2017.
Ongoing outreach and education will be critical to the successful implementation of the lateral
program and staff has begun to schedule, brainstorm and engage to develop successful outreach.
Discussion with other agencies that have similar programs or requirements and what they have
learned will also help shape the outreach program.
Because aspects of the programs will require some time to achieve meaningful outreach and
discussion and ideas regarding inspection, repair and/or replacement are in the primary phases, a
phased implementation approach is being considered. Below is a possible implementation
schedule.
ENVIRONMENTAL REVIEW
No environmental review is required for a study session.
FISCAL IMPACT
This is a study session and there is no fiscal impact associated with it. Fiscal impacts will be
developed for consideration with the Private Sewer Lateral Ordinance for City Council
consideration.
7/1/17
Begin
wastewater
flow offset
program
8/15/17
Begin
rebate
program
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FOCUSED QUESTIONS FOR CITY COUNCIL DIRECTION
Yes No
1. ACCELERATED REDUCTION APPROACH
To reduce inflow and infiltration:
Should the City develop an accelerated I/I reduction
program?
2. WASTEWATER FLOW DEVELOPMENT OFFSET
PROGRAM
To reduce inflow and infiltration:
a. Should the development offset program be Citywide?
b. Should the development offset program be focused on
capacity constrained areas?
3. LATERAL REBATE PROGRAM AND COST RECOVERY
To reduce inflow and infiltration:
a. Should program funding be available citywide?
b. Should larger rebates be offered to the capacity constrained
areas?
c. Should there be restrictions on property types eligible for
rebates?
d. Should the City consider less than 100 percent cost recovery
for permit fees associated with private sewer lateral
replacement?
Attachments:
a - October 2016 Council Agenda Report
b - California River Water Settlement Agreement, July 6, 2016
c - Capacity Constrained Areas
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Meeting Date: 10/4/2016
FROM: Carrie Mattingly, Utilities Director
Prepared By: David Hix, Deputy Director, Wastewater
Jennifer Metz, Utilities Project Manager
SUBJECT: WASTEWATER COLLECTION SYSTEM CAPACITY CONSTRAINTS
RECOMMENDATION
Receive a presentation on the impact of inflow and infiltration on the City’s wastewater collection
system and current capacity constraints.
DISCUSSION
Wet weather capacity constraints were identified in the wastewater collection system during the
Wastewater Collection System Infrastructure Renewal Strategy presented to City Council on
January 19, 2016. Currently development inquiries are taking place in areas that are impacted by
these system capacity constraints. Measures which are being required by the City to create wet
weather capacity in these problem areas are causing some confusion and concern. Raising general
community awareness about these collection system capacity constraints and communicating, at a
high level, what is being done to address the problem is the goal of this study session.
Background
Clean water is critical for sustaining life and the health of any community, yet people often take
for granted the flow of used water (wastewater) out of their homes or businesses. Wastewater, once
it disappears down sinks, toilets, floor drains or other outlets, flows through a network of
underground sewer pipes (known as the wastewater collection system) making its way to water
resource recovery facilities where it is cleaned and safely reused and/or released back to the
environment.
The City of San Luis Obispo’s wastewater collection system includes 137 miles of sewer lines and
2,900 manholes with the majority of the City’s collection system being six-inch clay pipe.
Depending on the topography, wastewater flows to the water resource recovery facility either by
gravity or with the assistance of lift stations. Like many older cities, portions (about 13%) of the
City’s sewer pipe inventory pre-dates World War II. 18 miles of pipeline currently in service was
installed prior to 1940. Some pipe installed in 1910 is still in service, well beyond its expected
service life.
In addition to the main lines, there are 14,000 private sewer laterals (approximately 172 miles in
length) that connect individual properties within the City to the wastewater collection system.
These private sewer laterals are the property owner’s responsibility and are not maintained or
replaced by the City.
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Inflow and Infiltration
With Council’s and the ratepayers’ support over the past 25 years, progress has been made in
reducing sanitary sewer overflows and service interruptions. Between 2007 and 2015 the
community has invested over $25 million in replacement and repair projects that benefit the
wastewater collection system. Ongoing comprehensive maintenance activities continue to improve
the function of the wastewater collection system.
Despite these investments, the City’s collection system and the Water Resource Recovery Facility
WRRF) continue to experience problems associated with excessive wet weather inflow and
infiltration. Flows into the City’s collection system and, ultimately, to the WRRF increase from an
average of 3.5 million gallons to over 25 million gallons a day when it rains. While it may be of
little comfort, this problem is not unique to San Luis Obispo as there are many communities in
California, and across the country, dealing with similar inflow and infiltration issues. Additionally,
the drought may be exacerbating the problem as tree roots searching for a water source can open
up ever-larger cracks in pipes.
Because of inflow and infiltration’s impact on the community’s ability to safely convey and
adequately treat its wastewater, the City’s Water and Wastewater Element of the General Plan has
policies and programs to address it. Inflow and infiltration, often referred to as I&I, describes two
distinct mechanisms for how stormwater enters the sewer system.
Inflow is water that enters the City’s wastewater collection system at points of direct
connection and is usually induced by a rain event. Private residences may have roof,
yard area, or foundation drains inappropriately and illegally connected to sanitary
sewers. Any extra water flowing into wastewater collection systems from above-
ground sources, either intentionally or unintentionally, is referred to as inflow.
Infiltration is water that flows through the ground that can seep, trickle, or flow into
the wastewater collection system through cracks in sewer mains and/or private
sewer laterals. These cracks may be caused by age-related pipe deterioration, loose
pipe joints, poor design, installation or maintenance errors, damage, or root
infiltration. Water can enter these cracks wherever sewer lines lie beneath
groundwater tables or the soil above the sewer system becomes
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saturated.
High rates of I&I into sewer pipes exceed the capacity of the wastewater collection system which
leads to system backups and/or overflows. Overflows occur at manholes and usually flow to nearby
storm drains or creeks. Overflows can also occur at private homes or businesses resulting in
property damage. Overflows are of considerable concern to the City and our regional regulatory
partners.
I&I impacts the efficiency of treatment at the City’s WRRF. Peak wet weather flows require
treatment processes and equipment to be sized large enough to handle the peak flows. The
biological treatment processes become less effective when these large amounts of water come
through into the WRRF thereby increasing the chance of NPDES (National Pollutant Discharge
Elimination System) permit effluent violations.
Past Studies and Programs
A study conducted by the City’s wastewater collection
system operators in the early 1990s found that private
sewer laterals connected to the City’s wastewater
collection system contributed to significant I&I problems.
The study’s findings indicated that failures were mostly
due to poor installation and pipe construction materials
including Orangeburg pipe (a coal tar impregnated wood
fiber pipe) or joint failure in clay pipe. Due to I&I
problems, the City’s lateral construction standard changed
during the 1980s to no longer allow the use of Orangeburg
pipe for private sewer laterals.
In 1996, to help combat I&I problems, Council approved the Voluntary Service Lateral
Investigation and Rehabilitation Program. The program provided around 1,000 reimbursements
Sewer Lateral Ownership.
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for lateral repair or replacement due to troublesome Orangeburg pipe, structural deficiencies, and
root intrusion. The voluntary program provided free construction permits, free technical advice
and a rebate of one-half the cost of replacement or repair up to a maximum of $1,000 per property.
Funding for this program was discontinued in 2011 to focus resources on conducting a flow study
of the collection system, identifying the areas most impacted by I&I, and completing a holistic
strategy (including prioritized pipeline replacements) for the management of the City’s wastewater
collection system’s infrastructure.
Recent Studies
The City concluded two years of flow monitoring and data collection with the completion of the
Sanitary Sewer Flow Monitoring and Inflow/Infiltration Study in March 2012. This study
identified base flows, peaking factors, and capacity issues, such as where surcharging (flow in the
pipe is more than the pipe can accommodate) is evident and overflows are possible. Incorporating
the flow monitoring data from the study and twenty years of maintenance and pipeline condition
data collected in its asset management database, the City completed the Wastewater Collection
System Infrastructure Renewal Strategy (Renewal Strategy) and hydraulic modeling in January
2016.
The Renewal Strategy presents a fact-based strategy to guide policy, operations, and asset
management planning decisions in an efficient and cost effective manner. The Renewal Strategy
included the City’s first hydraulic model of the collection system to evaluate growth, based on
growth level ‘realistic’ numbers, planned under the 2014 update to the Land Use Element. The
hydraulic model is a useful tool to incorporate changes to the infrastructure and test the impacts of
actual wastewater generation volumes proposed by new
development as opposed to the planning numbers. The Renewal
Strategy and the hydraulic model identified that in some areas of the
community, I&I is limiting existing capacity in the collection
system to safely accommodate additional “normal” wastewater flow
that could otherwise be accommodated in the wastewater collection
system.
The Renewal Strategy estimated the total cost to upsize sewer mains
to address peak wet weather capacity deficiencies at $30 million
Attachment A). The total cost to address all wastewater collection
system pipeline deficiencies was estimated at over $47 million.
So how does something like this I&I problem, that happens only
when it rains, impact the ability to accommodate additional
normal” wastewater flows, especially given the reduced “normal”
wastewater flows related to water conservation measures?
The City’s wastewater system is highly regulated by state and federal agencies. The City is
mandated by the State of California and regulated under a statewide General Waste Discharge
Requirement to implement a Sewer System Management Plan that requires the collection system
have adequate capacity to convey peak wet weather sewage flows. The City has been making that
assurance through an aggressive maintenance, inspection, and capital program that has invested a
In some areas of the
community inflow and
infiltration impacts may
limit the ability for the
wastewater collection
system to safely
accommodate
additional “normal”
wastewater flow.
based on 2016
Renewal Strategy data
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total of $37.8 million on wastewater collection system and WRRF capital improvements from
2007 to 2015 with another $19.5 million currently underway. These efforts have reduced the
number of overflows resulting from stoppages and rainwater I&I in the past 25 years (with 53
stoppages in 1990 and 21 stoppages in 2015). Progress is being made, but evidence of significant
I&I continues to be of concern and private sewer laterals are known major contributors to the I&I
problem.
In contrast to City sewer mains, privately owned laterals generally are not maintained until they
fail. The City’s Municipal Code requires the following maintenance:
D. Maintenance of House Sewer Connections. The property owner will be
responsible for all construction, maintenance, improvements and repairs of the
sewer lateral including all house connections, industrial sewers, private sewage
disposal systems and appurtenances thereto, now existing or hereafter constructed.
Laterals shall be maintained by the owner of the property in a safe and sanitary
condition; and all devices or safeguards which are required for the operation
thereof shall be maintained in a good working order. If a property owner fails to
maintain the abovementioned wastewater facilities in a safe and sanitary condition,
the director may order and require termination of water service to the parcel and
all structures connected to the sewer outlet subject to these conditions. The water
service shall not be reinstated until the maintenance or installation of appropriate
wastewater disposal facilities has been approved by the director. (Ord. 1598 § 1
part), 2014)
Enforcement of private sewer lateral maintenance is difficult because they met the building code
when installed, are primarily “out of sight, out of mind,” and while impacting the City with I/I,
may result in no maniantence or service issues to the homeowner.
Impacted Areas
Although I/I is wide spread throughout the City, Attachment A shows areas most impacted by
existing capacity deficiencies in the wastewater collection system during peak wet weather. They
include the Laguna Lake area, the areas north and south of Foothill west of Santa Rosa Road, areas
north of South Street south of the downtown core, areas south of Pismo Street east of Santa Barbara
Road and north of the Union Pacific Railroad tracks. These areas of the collection system
experience “surcharging”, a condition where the gravity sewers are overloaded beyond its pipe full
flow capacity. (See Attachment B)
New development may be proposed in these areas of the City that are currently experiencing
surcharging of the collection system due to I&I. In some of these cases, the City would not be able
to permit the development unless additional capacity is created in the system. While the collection
systems for these areas were designed to accept normal flows, the model shows that peak wet
weather flows have the potential to overwhelm the system creating system overflows. When these
situations occur, the City will work with developers to identify projects, such as sewer lateral
replacements, that mitigate the impact of new wastewater flows. In addition, projects that the City
may undertake, such as upsizing sewer mains or other capacity building projects, could
accommodate wet weather flows and create additional capacity in these impacted areas. In any
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case, when new development is proposed, the City will evaluate that development to make sure
that a given project’s anticipated “normal” wastewater generation will fit in the pipe during wet
weather and not further exacerbate a known surcharge condition. Currently, the City is working
on a variety of solutions, and is tracking the capacity created by new infrastructure projects so that
information about capacity in the wastewater collection system can be shared with property owners
and developers.
If a project cannot reasonably offset its incremental impacts on the wastewater collection system,
the City would not be able to issue permits to allow construction of the project as allowing such a
connection would be in violation of the City’s State Waste Discharge Requirements.
Next Steps
There is no quick fix for I&I. This will be a long-term, multi-generational, work effort. The work
done to-date provides the foundation for a successful path forward and provides tools that allow
for adjusting the plan as more information becomes known. A method to efficiently track metrics
that will show to what extent I&I is being impacted by efforts taken must be developed. Staff will
be submitting CIP recommendations from the Renewal Strategy and its pipeline repair
prioritization for consideration during the upcoming financial planning process.
According to the Environmental Protection Agency, private lateral inspection and
repair/replacement programs can be an effective way of addressing I&I. Several programs were
reviewed as part of the Renewal Strategy. Through a settlement agreement with a third party, staff
will be recommending an ordinance requiring inspections of private laterals which may lead to
their repair or replacement. These inspections would be triggered by:
1. The sale or transfer of ownership of a property,
2. If two or more overflows within a year occur at a property, or
3. Where an applicant for a planning or building project indicates the addition of sewer
flow such as a bedroom or bathroom addition.
Staff will also be requesting a voluntary lateral replacement rebate program to assist homeowners
with needed or required repairs or replacements for the 2017-19 Financial Plan.
Once multiple options to reduce I&I from private laterals have been identified and developed to a
point allowing for meaningful discussion, community stakeholder engagement will occur prior to
bringing recommendations to Council. In the meantime, the Utilities Department will work with
applicants proposing development in impacted areas to identify ways to create additional peak wet
weather capacity in the collection system so projects can move forward. The following table
provides the range of potential options that Staff will be evaluating to comprehensively address
the I&I issue.
Table 1: Inflow and Infiltration Reduction Measures
Short-term Measures:
Work with developers to create peak wet weather capacity to accommodate new
development in capacity constrained areas
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Continue to require inspection of private sewer laterals as condition of approval on
discretionary projects that generate wastewater
Moderate-term Measures:
Develop private sewer lateral rehabilitation program for Council consideration.
Develop ordinance identifying additional triggering events for private sewer lateral
inspections for Council consideration.
Develop options or requirements for new development to mitigate new wastewater
flows.
Long-term Measures:
Sewer main replacement to address capacity constraints as part of Sewer Fund capital
improvement program
Continued monitoring of wastewater flows
FISCAL IMPACT
This is a study session and there is no fiscal impact associated with it. Fiscal impacts will be
developed in conjunction with any I&I program developed for Council consideration.
Attachments:
a - Pipes Over Capacity
b - Capacity Constrained Areas
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Inflow and Infiltration Reduction and
Private Sewer Lateral Program
Study Session
April 4, 2017
Within the presentation we have identified the
material related to Focus Questions with this icon
City's Wastewater Collection System
136 miles of pipeline
Well-documented .
condition
Regularly maintained
and repaired
Primarily located -
under streets
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Private Sewer Laterals
172 miles /-14,000
connections
Condition largely
unknown
Repaired or replaced
after complete failure
Primarily located
under yards
Private Sewer Laterals
Cracked Clay Lateral with Roots
Y
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4/5/2017
Private Sewer Laterals
STANDARD SPECIFICATIONS S
ENGINEERING STANDARDS
JANUA 2016
PUBLIC WORKS DEPARTMENT
ENGINEERING DMSION
919 vaM 6Yae1
9m Lw OtiWo, A9Ja91
190511AI 1LIp
Inflow and Infiltration
77-3.02A(5) Sewer Latera! Pipe
New and repaired ,ewer €aterrl pipe may be:
1. PVC SDR 35
2_ P'IC Schedule 40
3. HDPE SDR 17
4_ ABS Schedule 40
Inflow and Infiltration
Studies completed in 2012 and 2016 show that 1/1 is wide
spread, but certain areas affected more than others
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6
5
4
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2
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2azzoo
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L7, iz M M I I
Capacity Constraints during Wet Weather
L.g..d
lo.
T.
CITY OF SRI) LUIS OBISPO
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Capacity Constraints during Wet Weather
North and south
of Foothill west
of Santa Rosa
Road
Laguna Lake j
South of Pismo Street
east of Santa Barbara
Road and north of the
Union Pacific Railroad
tracks
ve -2
6f t
North of South
Street south of the
downtown come
Inflow and Infiltration Reduction
Benefits and Goals
i
4/5/2017
5
Settlement Agreement
City entered into Settlement Agreement -- '
with California River Watch included
triggers for a sewer lateral inspections
Sale or transfer of ownership of a
property
If two or more overflows occur at a
property; or
Building permit applications for
projects that will add sewer flow
Rebate Program
Staff will be proposing Voluntary Sewer Lateral
Rebate Program in the 2017-19 Financial Plan
w
ai
4/5/2017
D
Other Inflow and Infiltration
Reduction Programs
What could an Accelerated Reduction Program look like?
Inspection, repair, and replacement deadline for different uses
Identification of possible target areas
Monitoring and reporting progress
Other Inflow and Infiltration
Reduction Programs
Wastewater Flow Development Offset Program
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Other Inflow and Infiltration
Reduction Programs
Plumbing Permit $225
Encroachment Permit $800
Wye Installation 500
Total Estimated Permit Cost $1,525
Outreach Efforts
INFLOW AND INFILTRATION
Send Now!
4/5/2017
n
Implementation Timeline
May 16, 2017 — Present Private Sewer
Lateral Program Ordinance to City Council
May 22, 2017 — Continue Private Sewer
Lateral Program Outreach
July 1, 2017 — Begin Wastewater Flow
Offset Program
August 15, 2017 — Begin Rebate Program
January 1, 2018 — Begin Transfer of
Ownership Private Sewer Lateral Program
c O
ti(0
Questions and Feedback
4/5/2017
a
Focused Questions for City Council Direction
va do
LACCELERATED REDUCTION APPROACH
Th rcdncc innow and infiltration:
Should The City develop an accelerated 1/1 reduction
roam?
2. WASTEWATER FLOW DEVELOPMENT OFFSET
PROGRAM
To reduce inflow and infiltration: _
a. Should the davclopmant offset program he Citywide?
b- Should the development offset program be focused on
capacity constrained areas?
3. LATERAL REBATE PROGRAM AND COST RECOVERY
To reduce inflow and infiltration: _
a. Should program funding be available citywide?
b. Should larger rebates be offered to the capacity constrained
areas?
c- Should there be re5imuonF on property types eligible for
rcbatc{' _
d. Should the Cily considrr leu than 100 percent cost recovery
for permit fees associated with private sewer lateral
replporment?
Wastewater Flow Offset through
Private Lateral Rehabilitation
Flow Offset example for a 20 -unit Multi -Family Residential Project:
20 units Proposed multi -family residential units
110 gallons wastewater generation in gallons per multi -family unitperunit
330 gallons peak flow in gallons per multi -family unit (peaking factor of 3) per unit
6,600 gallons Peak flow to be offset by private lateral rehabilitation
791.20 feet Total length of private lateral to be rehabilitated (at 17 gallons per foot)
5.97 laterals Total number of private laterals to be rehabilitated (at an average of 65
feet per lateral)
6 laterals Rounded number of laterals to be rehabilitated
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