HomeMy WebLinkAbout11/20/2001, B4 - WATER USE OFFSET PROGRAM ALTERNATIVES. i
council Mn� Da
Nov.
20, 2001
ac,Enoa izEpont 13
CITY OF SAN LUI S O BI SPO
FROM: John Moss, Utilities Director
Prepared By: Ron Munds, Utilities Conservation Coordinator
SUBJECT: WATER USE OFFSET PROGRAM ALTERNATIVES.
CAO RECOMMENDATION
1. Terminate the Water Use Offset Program as of January 1, 2002 as previously directed
2. Do not implement a new water use offset program for land development at this time,
and
3. Direct staff to continue to research and develop new water efficiency programs in the
Utilities Conservation Office for implementation in the future as appropriate.
DISCUSSION
At the July 12, 2001 special City Council meeting regarding water issues, the Council made the
determination to end the mandatory retrofit program (Water Use Offset Program) as a condition
for new development on January 1, 2002. The Council directed staff to prepare an analysis to
determine if there were other alternative water conservation measures, other than toilet
retrofitting, that could be required as a condition for new development.
Staffs analysis of the options available for a new water use offset program included a complete
review of the various water conservation programs and technologies available at this time. Key
to this review was the consideration of the long-term reliability of any new program, since the
City would be granting development based upon the savings yielded, the ability(and desirability)
for a private contractor to implement the program, and finally the cost per unit of yield. Based on
the above criteria and staffs review of the conservation technologies available, staff is unable to
recommend a new water use offset program to Council at this time.
Although the focus of the current Water Use Offset Program was geared towards toilet and
showerhead retrofitting, staff also considered all retrofit opportunities proposed by the retrofit
contractors, such as commercial washing machine replacement and improved water recycling
equipment at car washes. Typically, these alternatives did not yield the amount of water savings
that a toilet retrofit would achieve at a comparable cost per acre-foot. When evaluating
alternative retrofits, staff takes into consideration the long-term reliability of the estimated water
savings before approving the water offset value.. The surety of the water savings is of utmost
importance when considering any alternative program for new development to undertake as part
of the building application process.
Attachment 1 is a detailed evaluation of water conservation technologies and program options,
primarily focused toward single-family residential customers. Table 1 is a summary of the
analysis. Though a significant number of toilets and showerheads have already been replaced
throughout the City, staff has provided the evaluation of those measures for comparison purposes
to the other conservation options. The "Savings in Acre Feet' represents an estimated water
� -1
Council Agenda Report—Water Offset Alternatives
Page 2
savings assuming 100% saturation of the measure is achieved. The reliability factor is based
partly on empirical information and partly on a subjective evaluation by staff. A rating of 5
means the measure is highly reliable and subsequently, the lower the number, the lower the
anticipated reliability. When a range of estimated costs are given, the low end of the range
assumes .the City would pay only a portion of the cost of the measure (rebate) and that the
customer would pay the difference. The high end of the range indicates the full cost of the
program is paid by the City.
Table 1: Water Conservation Technology Summary
Measure Savinus in Acre Cost p. Acre Reliability
Feet Feet Factor
Toilet Replacement 1035 $340 to $640 4.5
Showerhead 300 Included in 4.5
toilet cost
Graywater 336* Unknown 2.0
Hot Water Recirculating 87 to 222 $1,000 to 2.0
Systems $1,785
Landscape Irrigation 282** Unknown 2.0
Public Information Unknow_ n Unknown 2.0
High Efficiency Washing 120 $1,000 to 2.0
Machines $5,625
* Actual water savings may be a reduced amount because of the State Health
Department's restrictions on the use of graywater.
** Actual water savings may be higher depending on technologies used.
As indicated in Table 1, there is still potential for water savings from the conservation measures
evaluated. The primary concern with the measures, other than toilet and showerhead
replacement, is the reliability of the predicted water savings. This is not to say that in the future
programs should not be developed to encourage the use of the various measures but more
information is needed and additional analysis must be completed before considering the yield
from the programs as a part of the City's water supply.
The following is a summary of the water conservation measures evaluated in Attachment 1.
Section 1: Ultra-Low Flush Toilets (ULF) Reliability Factor: 4.5
As previously stated, toilet replacement was included in the evaluation for comparison purposes
since a majority of the water savings has already been realized. The 1,035 acre feet of water
savings for toilet replacement assumes that all the toilets in the City have been retrofitted. Staff
estimates that there are approximately 39,000 toilets in both the commercial and residential
sectors. As of October 2001, approximately 75% or 29,700 toilets have been replaced which
represents about 780 acre feet of water savings on an annual basis. As can be seen in Table 1,
toilet replacement yields the highest amount of water savings at the least cost per acre foot and
Council Agenda Report—Water Offset Alternatives
Page 3
has a high level of reliability in terms ongoing water savings. That is why toilet replacement has
been and.will continue to be the highest priority of the water conservation program.
Section 2: Low-Flow Showerheads Reliability Factor: 4.5
Showerhead replacement, as with toilet retrofitting, was included in the evaluation for
comparison purposes. It is estimated that over 90% of the showerheads in the City have been
replaced which means a majority of the 300 acre feet of water savings is being realized. Again,
this is a highly reliable, high water saving and low cost water conservation measure.
Section 3: Graywater Reliability Factor: 2.0
Back in the early 1990's, graywater, which includes water from bathtubs, showers, bathroom
washbasins, and water from clothes washing machines and laundry tubs, seemed to be the next
"frontier" in terms of water conservation technology. In the height of the drought, several local
health agencies, including San Luis Obispo County, approved the use of graywater on a limited
basis. Up until that time, the use of graywater for outdoor irrigation was illegal. By 1994 the
State legalized the use of graywater but under very stringent application conditions. There were
many companies and individuals that built an array of graywater systems, from very basic to fully
automated. Since 1994, the regulations have become even more stringent and most of the
companies, which built the systems, have gone out of business making it difficult to determine
the cost of systems built today.
The 336 acre feet savings, noted in Table 1, assumes all the graywater that is generated is needed
and would actually be an offsetting use for irrigation, including above surface applications such
as turf. Since above surface irrigation is not permitted per the regulations, the actual amount of
graywater that could be utilized would be significantly less than the 336 acre feet identified. The
reliability factor of 2.0 is based on the wide range of water savings estimates from the various
sources of graywater, the ability of the user to discontinue the use of the systems, the limitations
placed on graywater use by State law, and the degree of commitment from the user to properly
operate and maintain the system.
Section 4: Hot Water Recirculating Systems Reliability Factor: 2.0
Hot water recirculating systems work on the principal of providing instant hot water on demand
at all locations in a house. There are several variables, which affect the amount of water savings
that can be derived from these systems. The variables include:
• Size of household
• Plumbing layout
■ Square footage of dwelling
■ Customer habits
Of these variables, plumbing layout is the most significant. After consulting with plumbing
professionals, it is estimated that less than 50% of the existing homes in the City would benefit
from the installation of Hot Water Recirculating systems. Because of the number of variables, it ,/
Council Agenda Report—Water Offset Alternatives
Page 4
is difficult to derive a reliable water savings amount from these systems. This results in a wide
range of water savings estimated from these systems (87 to 222 acre feet per year) and a
reliability ranking of 2.0..
Section S: Landscape Programs Reliability Factor:2.0
Predicting water savings from landscape efficiency programs can be difficult. For instance, water
savings can vary from 30% to 70% when conventional landscapes are replaced with water
efficient plants. Another, often less expensive component of a landscape efficiency program is
improved irrigation management and upgrades of irrigation hardware. Based on the most current
information and the City's water use data from the years 1996, 1997 and 1998, approximately
282 acre feet per year could be achieved through an irrigation efficiency program.
The reliability factor of 2.0 is based on lack of quantitative data regarding water savings, the fact
that landscape plant materials can be changed to higher water using plants depending on
customer preference, and that the efficiency of irrigation systems can vary depending on the
customer's irrigation knowledge and management practices utilized in the operation and
maintenance of their system.
Section 6. Information and Education Program Reliability Factor: 2.0
The informational and educational component of the water conservation program provides an
essential service to our citizens by offering educational materials and assistance on how to save
water. Though water planning professionals agree these types of programs are necessary to
promote water efficiency, quantitative data is not available to predict reliable water savings and
determine a cost per acre foot for water saved through this type of program.
Section 7:High Efficiency Washing Machines Reliability Factor: 2.5
A high efficiency washing machine can save a significant amount of water and energy when
compared to conventional models. The average estimated savings per single family household
using a high efficiency washing machine is approximately 5,100 gallons of water per year
(California Urban Water Conservation Council) or about 120 acre feet per year if all residential
customers used this type of washing machine.
The reliability factor of 2.5 is due to the likelihood of the washing machine to leave the
community if a customer moves from the area.
Summary
Based on the above analysis of reliability and feasibility of available water conservation
technologies as new potential water use offset programs, staff does not recommend the
development and implementation of any of the remaining technologies as a water use offset
program at this time.
/�_A
l �
Council Agenda Report—Water Offset Alternatives
Page 5
As previously noted, the potential water savings versus the quantitative reliability of the
measures evaluated is very low. Staff believes that it would not be prudent to allow new
development to proceed using a technology that does not provide a high level of surety that the
water savings will be maintained over the long term. Though staff will pursue programs using
some of the options evaluated, having developers as the interface with the end user of the
technology is also not recommended at this time.
Additionally, to develop and implement a water use offset program based on technologies, other
than toilets and showerheads, would be staff intensive and require significant additional work to
develop a revised tracking system. Staff believes that it would be better to devote conservation
staff'time to the research and development of new programs and services provided by the
Conservation Office, and strengthen the programs already in place.
As new programs are implemented by the Utilities Conservation Office, their reliability will be
evaluated in terms of affect on the City's total actual water use. If over time trends show a
reliable lowering of the City's actual water use, the Council may wish to reconsider the City's per
capita use rate and/or the long term viability of these new programs. In fact, the per capita use
rate will be further discussed as various water policy issues are explored with the Planning
Commission in early 2002.
ALTERNATIVES
Select a conservation measure(s) and direct staff to develop a new water use offset program
based on that measure.
The Council could select a water conservation measure or measures, such as landscape irrigation,
and direct staff to develop a 'program to be implemented by developers. The advantage of
proceeding with this alternative would be that new program(s) would be developed and
implemented by local developers/contractors. The disadvantages are 1) the technologies
currently available do not produce quantitative, reliable water savings and 2) the technologies
evaluated are not as straight-forward and are more complicated in terms of installation and
operation by the user than a toilet. For these reasons, this alternative is not recommended. As
previously stated, many of the programs evaluated may be further assessed for implementation at
a future date as more complete information becomes available.
FISCAL IMPACT
There is no direct fiscal impact with the recommended action. Should Council choose to direct
staff to develop one or more of the identified conservation program options(alternative 1), Staff
will complete an analysis of the cost to develop, implement and administer the program and will
return to Council for funding and program approval.
ATTACHMENTS
Attachment 1- Water Conservation Evaluation
�_S
i
1
Attachment 1
WATER CONSERVATION EVALUATION
The following evaluation is based on an accumulation of information from multiple
sources and staff's past experiences with the various technologies. In evaluating the
water savings potential from water conservation technologies and programs, the
reliability of the potential savings is one of the most important considerations when
deciding to implement a program. Many components of a comprehensive water
conservation program have not been adequately studied to determine reliable water
savings. Staff has attempted to objectively evaluate the potential for each technology or
program and then determine the reliability of the estimated savings. Staff has developed
a rating system to measure the reliability of each component. The reliability factor is
based partly on empirical information and partly on subjective evaluation by staff. The
rating system is based on the following criteria:
• Availability of quantitative data
■ Ongoing, long term dependability of the water efficiency measure
■ Public acceptance of the water efficiency measure
The reliability factor uses a scale of one to five and reflects the criteria previously
outlined. A factor of five means that the savings can be definitely counted on as
permanent ongoing water savings.
Water Conservation Technologies
Water conservation technologies have advanced significantly over the last several years.
The California Urban Water Conservation Council (CUWCC), in which the City is a
member, has been funding studies to quantify various conservation measures from a
reliable water savings perspective, as well as from cost to benefit viewpoint. Many of the
studies are either in progress and have not been completed or are in the process of being
initiated. This analysis is limited to technologies which are associated with the largest
uses of water; indoor water use, graywater systems, landscape and public information
programs,which can potentially yield reliable water savings:
Technology Reliability Factor
Section 1: ULTRA-LOW FLUSH TOILETS 4.5
Section 2: LOW-FLOW SHOWERHEADS 4.5
Section 3:`GRAYWATER SYSTEMS 2.0
Section 4. HOT WATER RECIRCULATING SYSTEMS 2.0
Section 5: LANDSCAPING 2.0
Section 6: INFORMATION& EDUCATION 2.0
Section 7:HIGH EFFICIENCY WASHING MACHINES 2.5
Water Conservation Evaluation Attachment 1
Page 2
Section 1 ULTRA-LOW FLUSH TOILETS (ULF) Reliability Factor: 4.5
As of January 1993, all toilets sold in the State of California must meet the ULF standard
of 1.6 gallons per flush or less. A study was completed in June 1992, funded by the
Metropolitan Water District of Southern California, to evaluate toilet replacement
programs and establish reliable water savings projections. This study has been endorsed
by the CUWCC and is now recognized as a statewide standard for toilet replacement
programs. The reliability rating of 4.5 is based on the quantitative data available from the
Metropolitan Water District's ULF toilet replacement study completed in June 1992, the
20 plus year operational life of a toilet and the public's approval of the technology derived
from a City survey conducted in 1991.
Table 1: ULF Estimated Water Savin
ULTRA-LOW FLUSH TOILET
Estimated Water Savings(acre feet per year)
Single Family l/ 350 afy Assumes 41.9 gallons/dcoAousehold
multiplied by 7,500 households.
Multi-Family 1/ 325 afy Assumes 53 gallons/day/dwelling
multiplied by 5,500 dwellings.
All Others 2/ 360 afy Assumes 27 gallonslper toiletlper day
multiplied by 12,000 toilets.
TOTAL 1035 acre feet per year("afy")
Notes:
l/Single family and multi-family gallons/day/household derived from information contained in the
Metropolitan Water District.toilet replacement study.Households and dwellings based estimated pre-1992
construction.
2/Based on average water use factors for retrofitted ULF toilets.Number of toilets estimate based on study by
the CUWCC.
Based on the figures provided in the study, it is estimated that the water savings at 100%
toilet retrofit in the City is 1035 acre feet(af) per year as summarized in Table 1. In
performing the cost evaluation, staff examined the total amount of capital required to
fund the current Retrofit Rebate Program to 100% completion of retrofitting and the cost
of a program where the City pays the full cost of the toilet retrofit. Table 2 summarizes
the results of the analysis, which includes the cost per acre-foot to the City.
Water Conservation Evacuation Attachment 1
Page 3
Table 2: ULF Program Com letion Cost/Acre Feet
ULTRA-LOW FLUSH TOILET
Cost Evaluation
Assumptions: (installation costs do not include floor covering changes or sub floor rehabilitation.)
1. Cost per toilet $85 to$300
2. Cost for installation $50 to$100
Alternative A. Voluntary Retrofit Rebate Program
(Assumes 75%change-out of existing toilets as of 10/01 and$100 rebate)
Total $800,000
Cost per acre foot $340 over a ten year period
Alternative B: Mandatory Retrofit Program
(Assumes 75%change-out of existing toilets as of 10/01 and the City pays all costs;cost to replace
standard toilet and labor is estimated at$185/toilet. Costs for flooring changes and additional
charges for custom toilets not included.)
Total $1.5 million
Cost per acre foot $640 over a ten year period
Section 2: LOW-FLOW SHOWERHEADS Reliability Factor: 4.5
The current State standard for low-flow showerheads is a flow rate of 2.5 gallons per
minute. In order to calculate long-range water savings from showerhead replacement, the
projected savings are based on water use and population figures from 1993, the year the
state standard changed to 2.5 gallons per minute.
It is estimated that 300 acre feet per year of water savings will be achieved at 100%
retrofit of showerheads. Table 3 summarizes the total estimated water savings and
assumptions used to calculate the estimated water savings.
Table 3: Low Flow Showerheads Estimated Water Savffigs
LOW-FLOW SHOWERHEADS
Estimated Water Savings
1993 Population 43,415
Average savings *6.2 gallons/person/day
TOTAL Estimated.savings 300 af/year
(*based on Rocky Mountain Institute data)
O
Water Conservation Evaluation `_Ji Attachment 1
Page 4
The CARE Program, (joint effort with PG&E)initiated in 1987 and implemented in
1988, replaced an estimated 27% of the showerheads in the City during that year.
Since1988, low-flow showerheads have been a requirement in new construction and
thousands were replaced during mandatory water conservation. It is estimated that 80%
to 90% of the showerheads in the City are currently low-flow which means the City has
already captured the majority of the water savings associated with these fixtures.
Section 3: GRAYWATER Reliability Factor: 2.0
Graywater is defined as untreated household wastewater, which includes water from
bathtubs, showers, bathroom washbasins, and water from clothes washing machines and
laundry tubs. It does not include water that has come into contact with toilet waste,
kitchen sinks, dishwashers or laundry water from soiled diapers. Up until 1989, the use
of graywater was not regulated in the State of California and was viewed as an illegal use
of household wastewater by local health agencies.
During 1989/1990, several counties and cities, including San Luis Obispo, legalized the
use of graywater as a drought emergency measure. In July 1992 legislation was passed
which directed the Department of Water Resources (DWR) to develop graywater use
regulations. DWR working with the Department of Health Services and other concerned
organizations and individuals, spent 18 months developing standards designed to protect
public health while establishing a uniform set of statewide standards.
On March 8, 1994 the California Building Standards Commission approved the
Graywater Standards as part of the California Plumbing Code and restricted the
application of graywater to single family dwellings. In 1997, the Building and Standards
Commission revised the standards to include commercial, industrial and multi-family
projects. In 2000, the Department of Health Services required that any property using a
graywater system install an approved backflow prevention device to eliminate the
possibility of contamination to the domestic potable water supply in the event of a cross
connection between the two systems.
Even though the regulations have changed to include a wider range of potential users,
realistically the only practical use of graywater is still in the single-family residential
sector given the restriction and system design standards. The following analysis is based
on this assumption for graywater use.
The reliability factor of 2.0 is based on the wide range of water savings estimates from
the various sources of graywater, the ability of user to discontinue the use of the systems,
the limitations placed on graywater use by State law and the degree of commitment from
the user to maintain the systems. Table 4 summarizes the assumptions and results of the
analysis.
�-9
Water Conservation Evacuation Attachment 1
Page 5
Table 4: Graywater Estimated Water Savings
GRAYWATER
Estimated Water Savings
EXISTING SINGLE FAMILY U
Assumes a total of 7,500 single-family dwellings. Slab foundations are assumed on 75%of the
dwellings and raised foundations on 25%of the dwellings. (75%of 7,500=5,625; 25%of 7,500
= 1,875)
Raised Foundation 2205 afy 2/ Assumes 105 gallons/day/household
multiplied by 1,875 dwellings.
Slab Foundation 2835 afy 3/ Assumes 45 gallons/day/household
multiplied by 5,625 dwellings.
TOTAL 504 acre feet per year("afy")
Less Seasonal Demand 336 acre feet per year 4/
(4 Months)
Notes:
1/ Multi-Family,institutional and commercial excluded.
2/ Assumes 35 gal/person/day and an average of 3 persons per household for al_graywater
sources(this is an average of the State's published guidelines and a study performed by
LADWP completed in June 1993.
3/ Based on the recently adopted State guidelines for graywater use for laundry wash water
(15 gallons per person per day)since this is the only practical graywater source for slab
foundations.
4/ These savings assume that all the graywater is needed for irrigation for 8 months of the
year;that this amount of potable water would have been used and that all potential
Locations are able to use graywater.
The regulations greatly restrict the application of graywater. The primary limitations are
1) the water application setback requirements from adjoining properties, 2) application
can only be sub-surface, 3) soil conditions must allow for adequate infiltration without
puddling or runoff, and 4) water application must be at a sufficient distance above the
groundwater level to avoid potential water contamination.
Additionally, a property using graywater must have backflow protection at or in close
proximity to the water meter and must be inspected annually. As noted in the Table 4, the
336 acre feet savings assumes all the graywater generated is needed for irrigation,
including above surface applications such as turf, and is actually offsetting the use of
potable water for that purpose. Since above surface irrigation is not permitted per the
I��
Water Conservation Evaivation - Attachment 1
Page 6
regulations and 100% use of all graywater is not likely,the actual amount of graywater
that could be utilized would be significantly less than the 336 acre feet identified.
Cost Evaluation
When the expanded use of graywater became more prevalent during the early 1990's,
innovative graywater systems became available. At that time, systems ranged from a cost
of around $400 for low-tech systems to upwards of$3,000 for fully automated systems.
The most.recent information regarding graywater systems cost comes from a 1997/98
study funded by the Department of Water Resources. The low-tech system costs
approximately$1,200 to install with the resident providing much of the labor. The
higher-tech system costs about $5,400. The increase in costs from earlier systems can be
attributed to the restrictive regulations now in place. Additionally, since the 1997/98
study, the regulations have changed so that systems must include a backflow prevention
device which adds to the cost. Based on the results of the study, graywater systems are
not cost effective in terms of payback to the customer unless subsidized by the water
utility.
In researching local companies that install graywater systems, it was discovered that the
closest installer specializing in graywater systems is in Santa Barbara and all the
companies that developed automated systems in the early 1990's have gone out of
business. This means that locally, systems could cost substantially more since each
system would have to be designed and built on a project-by-project basis.
Other Concerns: Although the State had developed regulations to allow the use of
graywater, the City's Utilities Director considers graywater use to be an unmanaged and
understudied use of wastewater and recommends against programs encouraging its use.
Section 4. HOT WATER RECIRCULATING SYSTEMS Reliability Factor: 2.0
Hot water recirculating systems work on the principal of providing instant hot water on
demand at all locations in a house. By drawing hot water from the hot water heater and
recirculating the cold water from the hot water line back to the heater, a significant
amount of water may be saved. There are several variables which affect the amount of
water savings which can be derived from these systems. The variables include:
■ Size of household
■ Plumbing layout
■ Square footage of dwelling
■ Customer habits
Of these variables,plumbing layout is the most significant. After consulting with
plumbing professionals, it is estimated that less than 50% of the existing homes would
benefit from the installation of this type of system. Most older homes are not plumbed
Water Conservation Evacuation Attachment 1
Page 7
with complete looping of hot and cold water lines which means more than one of these
systems would be required to recirculate all the hot and cold water within the dwelling:
Table 7 summarizes the results of the potential water savings analysis.
Table 7: Hot Water Recirculating Systems Estimated Water Savings
HOT WATER RECIRCULATING SYSTEMS
Estimated Water Savings
Based on manufacturer information and discussions with plumbing contractors and product
users,the following water savings may be achieved:
Existing Single Family 43 to 105 Assumes 10 to 25 gallons/da)Aousehold
afy saved; 50%of existing dwellings.
New Construction 44 to 117 Assumes 3 to 8 gallons/day/household; and
afy additional population--13,100--at build out.
TOTAL 87 to 222 acre feet per year("afy")
Because of the number of variables, it is difficult to derive a reliable water savings
amount from this type of system. Table 8 summarizes the cost analysis for both a rebate
program and a program where the City pays for the system and installation.
Table 8: Hot Water Recirculatin S stems Cost Evaluation
HOT WATER RECIRCULATING SYSTEMS
Cost Evaluation
Assumption: The cost of a retrofu hot water circulating system is approximately$300. Installation cost is estimated at
approximately$150 to$250 depending on the location of the unit. The calculations use$200 for labor. Estimates are
based on 50%of existing homes.
Alternative A: Rebate Program-E)dsting Single Family (Estimated program cost:City paid rebate of$300).
TOTAL $300 X 3,750 dwellings $1;125,000
Cost per Acre Foot $1,000 based on 105 afy savings
Alternative B: Full cost paid by City
TOTAL $500 X 3,750 dwellings $1,875,000
Cost per Acre Foot $1,785 based on 105 afy savings
Section 5: LANDSCAPE PROGRAMS Reliability Factor:. 2.0
Predicting water savings from landscape efficiency programs can be difficult. For
instance, water savings can vary from 30% to 70% when conventional landscapes are
��z
Water Conservation Evaluation Attachment 1
Page 8
replaced with water efficient plants (RMI Water Efficient Landscaping 1994). Another,
often less expensive component of a landscape efficiency program is improved irrigation
management and upgrades of irrigation hardware. Water savings from landscape
irrigation improvements is estimated to be about 15% (California Urban Water
Conservation Council). To date, landscaping programs do not provide readily predictable
or measurable water savings due to lack of data on projects that have been carried out and
the difficulties in distinguishing landscape water savings from those caused by indoor
water efficiency projects and behavioral changes in reaction to drought situations (RMI
1994).
The reliability factor of 2.0 is based on lack of quantitative data regarding water savings,
the fact that landscape plant materials can be changed to higher water using plants
depending on customer preference, and that the efficiency of irrigation systems can vary
depending on the customer's irrigation knowledge and management practices. Water
efficient landscape programs, though difficult to predict water savings, should be a
component of an aggressive ongoing water conservation program implemented by the
City Utilities Conservation Office.
Landscape Water Use
In order to establish a baseline for landscape water use, staff analyzed water use
information from 1995, 1996, and 1997 actual billing information. This analysis
indicated the following:
Residential Landscape Water Use 1,070 acre feet/year
Multi-family Landscape Water Use 300 acre feetlyear
Dedicated Landscape Meters 510 acre feet/year
Total 1,880-acre feet/year
Using an estimated water savings of 15% from irrigation efficiency measures would
equate to a potential savings of about 282 acre feet per year from an irrigation efficiency
program. This assumes that all landscapes and irrigation systems are currently inefficient
and can be improved to meet the projected water savings goal. Staff believes the 15%
saving estimation is low and that additional water savings above the 282 acre-feet per
year is possible. Table 9 summarizes the results of the landscape irrigation water use
analysis.
Ll -/3
Water Conservation Evacuation Attachment 1
Page 9
Table 9: Landscape- Estimated Water Savings
Landscape Water Use and
Estimated Water Savings
Single Family 1,070 afy
Multi-Family 300afy
Dedicated Landscape 510 afy
Total 1,880 afy
15%reduction due to irrigation efficiency 282 afy
TOTAL savings due to 282 afy
irrigation efficiency
Commercial and Institutional Landscape Water Use
Additional water savings can be achieved in the commercial and institutional sectors that
have both domestic and landscape water uses on a single meter. Staff will be analyzing
this potential water savings as part of implementing Best Management Practice (BMP)
regarding large landscape irrigation efficiency.
Cost Evaluation Summary
Staff has not been able to establish a cost associated with water efficient landscape
programs because of lack of a quantitative data and conclusive studies.
It is recommended that a strong educational program be established and that additional
research be conducted to evaluate the feasibility of a monetary incentive program geared
towards water efficient irrigation hardware. Hardware currently being evaluated by the
CUWCC includes:
■ Soil moisture sensors
■ Rain shut-off valves
■ Evapo-Transpiration irrigation controllers
In order to develop cost effective irrigation and landscape programs, more information is
needed to substantiate reliable water savings.
Water Conservation Evaivation Attachment 1
Page 10
Section 6: INFORMATIONAL&EDUCATIONAL PROGRAMS Reliability Factor: 2.0
During mandatory water conservation, the informational and educational component of
the water conservation program provided an essential service to our citizens by offering
educational materials and assistance on how to save water: Though water-planning
professionals agree these types of programs are necessary to promote water efficiency,
quantitative data is not.available to predict reliable water savings. Because reliable water
savings cannot be determined, cost of such support programs should be factored into the
total cost of an over-all water conservation program.
The City has a very comprehensive public relations program, which includes the
following:
■ Public Workshops
■ In-school programs
■ Media advertising&promotion
■ Water efficient landscape awareness
Public event participation
■ Consumer product information
■ Indoor\irrigation water audits
■ Free printed information/brochures
Cost Evaluation Summary
Staff has not been able to determine a water savings value to perform a cost per acre-foot
analysis.
Section 7:HIGH EFFICIENCY WASHING MACHINES Reliability Factor: 2.0
A high efficiency washing machine can save a significant amount of water and energy
when compared to conventional models. The average estimated savings per single-family
household using a high efficiency washing machine is approximately 5,100 gallons of
water per year(California Urban Water Conservation Council). Most machines are front-
loading models, however there are a very small number of top-loading models that could
qualify.
The reliability factor of 2.5 is due to the likelihood of a washing machine to leave the
community if a customer moves from the area.
Water Conservation Evaivation Attachment 1
Page 11
Table 10: High efficiency Washin .Machine Estimated Water Savings
HIGH EFFICIENCY WASHING MACHINE
Estimated Water Savings
Based on average annual water savings per washer established by CUWCC:
Single Family Residential 120 afy Assumes 5,100 gallons/year/machine;
7,500 SF existing dwellings.
TOTAL 120 acre feet per year("afy")
Cost Evaluation Summary
Table I I summarizes the cost analysis for both a rebate program and a program where the
City pays for the washing machine.
Table 11: High Efficiency Washin Machine.Cost Evaluation
High Efficiency Wasting Machine
Cost Evaluation
Assumption: The cost of a high efficiency washing machine is approximately$800 to$1000.
Alternative A: Rebate Program-Existing Single Family (Estimated program cost:City paid rebate of$150).
TOTAL $150 X 7;500 dwellings $1,125,000
Cost per Acre Foot approx.$1000 based on 120 afy savings
Alternative B: Full cost paid by City
TOTAL $900 X 7,500 dwellings $6,750,000
Cost per Acre Foot $5,625 based on 120 afy savings
Section 8: SUMMARY
Table 12 summarizes the information contained in this evaluation. Though some of the measures
cannot be quantified as to cost effectiveness at this point in time, many warrant further evaluation to
determine if programs can be developed and implemented to achieve the estimated water savings in a
cost effective manner..
Water Conservation Evaluation Attachment 1
Page 12
Measure Savings in Acre Cost per Acre Reliability
Feet Feet Factor
Toilet Replacement 1035 $340 to $640 4.5
Showerhead 300 Included in 4.5
toilet cost
Gra water 336* Unknown 2.0
Hot Water Recirculating 87 to 222 $1,000 to 2.0
Systems $1,785
Landscape Irrigation 282** Unknown 2.0 _
Public Information Unknown Unknown 2.0
High Efficiency Washing 120 $1,000 to 2.0
Machines $5,625
Table 1: Water Conservation Technology Summary