Wholesale Demand and Conservation Savings

conservation

BY ELLEN R. LEVIN, WILLIAM O. MADDAUS,

NICOLE M. SANDKULLA, AND HEATHER POHL

FORECASTING Wholesale Demand and Conservation Savings

he San Francisco Public Utilities Commission (SFPUC) is a department of the City and County of San Francisco that provides water and wastewater services, and municipal power to the city. Under contrac- tual agreements, 28 wholesale water agencies (SFPUC wholesale cus- T tomers) in Alameda, San Mateo, and Santa Clara counties also purchase water from the SFPUC (Figure 1). The Bay Area Water Supply and Conservation Agency (BAWSCA) is a special district that was created to represent the interests of 26 cities and water districts and two private utilities in the three counties that purchase wholesale water from the SFPUC regional water system. INFORMATION ABOUT FUTURE WATER In all, nearly 2.4 million people rely at least partially on water supplied by the SFPUC regional water system to meet their daily water demands. DEMANDS HELPS WHOLESALE Nearly 85% of the SFPUC water supply is provided by the Tuolumne CUSTOMERS ASSESS OPTIONS River watershed via Hetch Hetchy reservoir in Yosemite National Park, 167 mi east of the San Francisco Bay Area. The remaining 15% of the SFPUC water AND DETERMINE WATER NEEDS. supply comes from Bay Area watersheds including Alameda Creek, Pilarcitos Creek, San Andreas Creek, and the San Mateo Creek watersheds via local Bay Area reservoirs (Figure 2). About 32% of SFPUC’s water supply goes to retail customers in the city; the remaining 68% is provided to wholesale customers and large retail customers outside the city. In general, the wholesale customers are located throughout the Bay Area’s different microclimates; some are in the cool coastal areas, and others are in the warmer inland areas. The wholesale customer service areas vary dramatically in size and character. Los Trancos County Water District, for example, encompasses 4.5 sq mi and serves approximately 270 residential

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102 FEBRUARY 2006 | JOURNAL AWWA • 98:2 | PEER-REVIEWED | LEVIN ET AL FIGURE 1 SFPUC wholesale customer service area

1 City and County of San Francisco 2 City of Brisbane 3 City of Burlingame 4a CWS, Bear Gulch District 4b CWS, Mid-Peninsula District 4c CWS, South San Francisco District 5 Coastside County Water District 6 Daly City 7 City of East Palo Alto 8 Estero MID/Foster City 9 Guadalupe Valley MID 10 City of Hayward 11 Town of Hillsborough 12 Los Trancos County Water District 13 City of Menlo Park 14 Mid-Peninsula Water District 15 City of Millbrae 16 City of Milpitas 17 City of Mountain View 18 North Coast County Water District 19 City of Palo Alto 20 Purissima Hills Water District 21 Redwood City 22 City of San Bruno 23 City of San Jose (portion of north San Jose) 24 City of Santa Clara Source: BAWSCA 25 Skyline County Water District 26 Stanford University BAWCSA—Bay Area Water Supply and Conservation Agency, CWS—California Water 27 City of Sunnyvale Service (company), MID—Municipal Improvement District, SFPUC—San Francisco 28 Westborough Water District Public Utilities Commission accounts. Alameda County Water future water demands, water con- wholesale customers better assess District encompasses approximately servation potential, and recycled their options for meeting future water 103 sq mi and serves 77,000 resi- water potential in its retail and needs and decide how much water dential, commercial, industrial, and wholesale customer service areas. they plan to purchase from SFPUC’s institutional accounts. In addition These studies were aimed at assist- regional water system in the future. to collectively using 68% of the ing the SFPUC in making long-term In addition, the results of these stud- SFPUC’s water supply to meet their water system–planning decisions for ies yield useful information to the total demands, many of the SFPUC’s wholesale customers have This study is one of the largest water demand other sources of sup- forecasting and conservation evaluation projects ply, such as local groundwater or water that has been undertaken in the United States. from another local wholesale water agency. the region and at gaining a better commission in terms of the potential SFPUC is currently implementing understanding of the total demand for developing incentive programs to the Water System Improvement Pro- needs of its customers. The structure encourage further conservation and gram (WSIP), a capital improvement of SFPUC’s individual contracts with water recycling in the wholesale cus- program to increase the reliability of its wholesale customers does not pro- tomer service areas. the regional water system and reduce vide the commission the authority to The studies for forecasting future its risk of failure. WSIP includes pro- impose local water supply–planning water demands, conservation poten- jects to repair and replace existing measures or alternative water sup- tial, and recycled water potential transmission and storage facilities ply use on its wholesale customers. were completed with considerable that are critical to providing a reliable These alternative water supplies interaction among the SFPUC whole- water supply to SFPUC customers. could include using locally produced sale customers, BAWSCA, and envi- In Fall 2002, the SFPUC recycled water or implementing con- ronmental groups concerned with the embarked on a number of compre- servation measures. The results of necessity of additional water supplies hensive planning studies to assess these studies were intended to help to meet future customer demands.

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LEVIN ET AL | PEER-REVIEWED | 98:2 • JOURNAL AWWA | FEBRUARY 2006 103 FIGURE 2 SFPUC water system

San Francisco Lake Eleanor Lake Cherry Reservoir Reservoir

Pacific Hayward Ocean O‘Shaughnessy Service Area Dam

Harry W. Livermore Hetch Tracy San Francisco Bay Filter Plant San Joaquinpipelines Tuolumne Hetchy River Reservoir Foothill San Andreas Tesla Tunnel Reservoir Portal Bay Division Pipelines San Antonio Numbers 1 and 2 Reservoir Pilarcitos Yosemite Crystal Springs Dam Coastal Range Reservoir National Park Tunnel Crystal Sunol Valley Springs Filter Plant Reservoir

Calaveras Palo Alto Reservoir

Bay Division Pipelines Numbers 3 and 4

SFPUC—San Francisco Public Utilities Commission

STUDY APPROACH SUPPORTS forecasting approaches in that it uses the benefits (potential water sav- CUSTOMER DECISIONS growth in number of accounts and ings) and costs of implementing var- It was critical to SFPUC as a water a complete breakdown of water uses ious water conservation measures wholesaler that the results of this by account type (end uses) to fore- into the future. study support the wholesale cus- cast water demands. Using an end- tomer’s decisions about how much use model also allows more consid- CURRENT WATER USE water to purchase from the commis- eration of the effects of targeted AND CONSERVATION sion in the future. Similarly, the conservation measures than is pos- EFFORTS DESCRIBED SFPUC needed a greater under- sible with a per capita or land use In 2001 and 2002, SFPUC’s standing of the potential for water demand model. wholesale customers collectively pur- conservation in the wholesale service The study approach involved the chased two thirds of their water sup- area. SFPUC representatives were res- following four steps: ply needs—approximately 170 mgd olute in forecasting future water (1) Develop baseline water (BAWUA, 2002)—from the regional demands while being able to assess demand by investigating current water system to serve a residential the effects of both passive and active water use and breaking it down into population of nearly 1.7 million peo- conservation. end uses. ple in a 460-sq-mi area. The remain- Because the SFPUC was interested (2) Investigate current and past ing demands in the wholesale service in (1) incorporating the effects of water conservation activities to area were met through a combina- existing plumbing codes and current understand the effects of such activ- tion of locally developed water sup- water conservation efforts in the ities on the baseline water demand. plies, groundwater, State Water Proj- wholesale service area into its (3) Apply the end-use model to ect and Central Valley Project water, demand forecast and (2) under- forecast future water demands while and reclaimed water. standing the potential for water con- incorporating the effects of the The SFPUC wholesale customers servation, an end-use model was con- plumbing codes and past conserva- have been practicing water conser- sidered the most appropriate tool for tion practices. vation since the mid-1970s. Water developing water demand projec- (4) Incorporate water conserva- conservation is an integral part of tions. This type of model differs from tion practices into the end-use a long-term water management straight per capita or land use–based model demand forecasts to assess strategy for the wholesale customers

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104 FEBRUARY 2006 | JOURNAL AWWA • 98:2 | PEER-REVIEWED | LEVIN ET AL and BAWSCA. All of the SFPUC wholesale customers implement some degree of water conservation. Measures Used to Evaluate Thirteen SFPUC wholesale customers, representing 74% of the total water purchased from the com- Service Area Conservation Potential mission by its wholesale customers, are signatories to the California Provide: Urban Water Conservation Coun- • residential water surveys cil’s (CUWCC’s) Memorandum of • residential retrofit kits to pre-1992 homes Understanding Regarding Urban • large landscape conservation audits Water Conservation in California • water budgets for large landscape areas (MOU). This MOU was developed • public information programs in 1991 among urban water agencies • commercial water audits to encourage the implementation of • home leak detection and repair program water conservation best manage- • Xeriscape education and staff training at retail garden/irrigation ment practices (BMPs). In addition, supply houses BAWSCA, also a signatory to the • free installation of restaurant spray rinse nozzles CUWCCC MOU, is committed to • free water audits to hotels/motels implementing water conservation • financial assistance to hotels for retrofits BMPs. The BMPs include • rebates to businesses that replace inefficient water-using equipment • interior and exterior water • onresidential customers with rebates for irrigation upgrades audits and incentive programs for single-family and multifamily resi- Rebate: dential customers; • high-efficiency residential clothes washers • residential plumbing retrofits; • commercial ultralow-flush toilets (ULFTs) and urinals • system water audits and leak • residential ULFTs detection and repair; • 6/3 dual flush or 4-L toilets • metering with commodity rates • residential evapotranspiration controller installation for all new connections and retrofit • high-efficiency multifamily clothes washers of existing connections; Require: • large landscape conservation • 1.6-gal/flush toilets be installed at the time of sale of existing buildings programs; • submetering multifamily units • horizontal-axis washing ma- • 0.5-gal/flush urinals in new buildings chine rebate programs; • dedicated irrigation meter for new nonresidential accounts • public information; • school education programs; Offer: • commercial, industrial, and • incentives for replacement of clothes washers in coin-operated laundries institutional water conservation; • incentives for retrofitting submetering multifamily units • wholesale agency assistance • financial incentives for complying with water use budgets 1 programs; Sponsor: • conservation pricing; • homeowner irrigation classes • employing a conservation • award program for water savings by businesses coordinator; • water waste prohibition; and Promote: • a residential ultralow-flush toi- • water-efficient plantings at new homes let rebate program. Enforce: Conservation in the areas served • landscape requirements for new landscaping systems (turf limita- by the SFPUC wholesale customers is tions/regulations) implemented in a coordinated fashion that reflects the uniqueness of the Encourage: service area. The wholesale customers • participation in the US Environmental Protection Agency’s Water retain primary responsibility for Alliances for Voluntary Efficiency program for hotels implementing conservation in their Create: service areas and implement a major- • water utility/city department water reduction goals ity of conservation programs inde-

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LEVIN ET AL | PEER-REVIEWED | 98:2 • JOURNAL AWWA | FEBRUARY 2006 105 been cost-effective or feasible other- FIGURE 3 Schematic of decision support system model as applied wise. Large agencies with well-devel- to an urban water agency or regional area oped water conservation programs also benefit from the assistance program because it allows them to con- Customer Billing Data serve more water at even lower cost.

Single-family Multifamily CommercialIndustrial Institutional DSS METHODOLOGY HELPS residential OBTAIN DEMAND PROJECTIONS

Demographic Standardized water use To determine future demand, the data Indoor/outdoor data by account type (national publications) SFPUC employed an end-use model; US Census water use the Demand Side Management Legend Input data Least-cost Planning Decision Sup-

Users per Water use Model process port System (DSS) model developed account by end use Output/results by a local water management com- Calibration Calibration pany.2 A DSS model was developed Fixture and Fixture for each wholesale customer to fore- replacement models Base-year conditions data Demand forecasting cast its 2030 water demands in its respective service area.

Final demand The DSS model is similar to other Population and Account projections employment growth end-use models such as IWR-Main, projections projections developed by the US Army Corps of Engineers, and the end-use model FIGURE 4 Total SFPUC wholesale customer area water demand the SFPUC has used for more than a projection decade to forecast water demand in its retail service area. The DSS model was selected for this study because it 360 Without plumbing code yields a more accurate representa- With plumbing code tion of changing conditions such as 340 7.8% the future effect of plumbing and 320 appliance codes on demand and

mgd additional planned conservation. The 300 DSS model also allows evaluation 280 of the effects of multiple conservation measures run at the same time 260 and targeted at the same end use Total Demand— 240 without the risk of double-counting water savings. 220 The DSS model (Figure 3) arrives 200 at future water demand projections 2000 2005 2010 2015 2020 2025 2030 2035 through two steps: (1) establishing Year base-year water demand at the end- SFPUC—San Francisco Public Utilities Commission use level (such as toilets and showers) and calibrating the model to initial conditions and(2) forecast- pendently. In addition, as BAWSCA Effective water conservation pro- ing the demand from the existing members, many of the SFPUC whole- grams are one of the key tools avail- water service accounts and from sale customers take advantage of able to BAWSCA’s members to growth in the number of water ser- regional conservation programs address the water supply challenges vice accounts. offered by BAWSCA and other and limitations they face. Both large Base-year water demand. The base- regional and state entities. and small agencies participate in year water demand at the end-use BAWSCA’s enabling legislation BAWSCA conservation programs. level is established by breaking down speaks directly to the need for coor- Small agencies take advantage of the total historical water use for each dinated planning and implementa- administrative resources BAWSCA type of water service account (such as tion of systematic, rational, cost-effec- provides, allowing them to imple- single-family, multifamily, commer- tive water conservation programs. ment programs that would not have cial, and irrigation) to specific end

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106 FEBRUARY 2006 | JOURNAL AWWA • 98:2 | PEER-REVIEWED | LEVIN ET AL uses (such as toilets, faucets, showers, and irrigation). After studying the FIGURE 5 Percentage breakdown of SFPUC wholesale customer water consumption by customer billing category SFPUC region’s water use data, 2001 was selected as the base year for the modeling. The year 2001 provided Other 13 the most recent water use data in a Single-family nondrought year and did not show Industrial 44 the effects of the slowing economy 9 (which caused some sectors of water use to decline). Future water demand. To forecast future water demand, the growth in Commercial 16 the number of water service accounts in a wholesale customer service area is determined based on published Multifamly population and employment fore- 18 casts for each city and county within the service areas. The demographic Source: SFPUC wholesale customer billing records forecasts were used to develop ser- SFPUC—San Francisco Public Utilities Commission vice-area-specific population and Base year-2001. Other category includes miscellaneous, institutional, municipal, employment growth projections. and irrigation/landscape uses where these water uses are metered separately. Each of the 28 wholesale customers agreed to these projections for their respective service areas. Using the rerun assuming that no water-efficient category between residential and non- DSS model, the projections were plumbing fixtures were in place. These residential uses. Figure 5 shows the applied to the appropriate water ser- results were also summed to obtain a 2001 (base-year) average water use of vice accounts and their end water total water demand projection without SFPUC’s wholesale customers by typ- uses to project future water demands. fixture replacement (Figure 4). Results ical customer-billing category. Figure The project team worked directly of this study can be found in SFPUC 6 shows the 2030 projections from with the 28 wholesale customers in Wholesale Customer Water Demand the DSS model by customer-billing setting up the base-year water use Projections (URS Corp., 2004a). category. A comparison of Figures 5 conditions in the model and in devel- Results of the DSS model for the and 6 reveals a slight decrease in the oping the service-area-specific demo- 2001 base year demonstrate a percentage of residential water use graphic forecasts. weighted average for the SFPUC (4%) and a slight increase in the per- The DSS model also incorporates wholesale customers’ residential water centage of nonresidential water use the effects of the plumbing and appli- use of 108 gpcd and 75 gpcd for sin- (4%) from 2001 to 2030. ance codes for fixtures and appli- gle-family and multifamily residen- ances, including toilets (1.6 gal/flush), tial accounts, respectively. For the CONSERVATION MEASURES showerheads (2.5 gpm), and wash- projected year 2030, before any addi- EVALUATED ing machines (lower water use) on tional conservation measures were In evaluating the wholesale cus- existing and future accounts. implemented, the weighted averages tomer service area conservation The aggregate results of the DSS of residential water use are 102 gcd potential, an initial list of 75 conser- model indicate that total 2030 water and 67 gcd for single-family and mul- vation measures was considered. This demands are expected to increase by tifamily residential accounts, respec- list included (1) rebate and other only 19% despite a projected 19% tively. Nearly all of the 2030 reduc- incentive programs for installing increase in population and a 31% tion is in indoor usage as a result of water-saving devices, (2) city/county increase in employment. This results the effects of the plumbing code. Fur- ordinances requiring the installation from the effect of the plumbing code, ther 2030 reductions in projected use of water-saving devices, and (3) edu- which reduces future projected de- after implementing additional con- cational outreach and award pro- mands by 7.8%. servation practices were identified as grams that promote water use reduc- Figure 4 shows the total water part of the conservation evaluation, tions in businesses and landscaping. demand projection as a sum of all described later in this article. The following qualitative criteria were wholesale customers, regardless of The rates of increase from 2001 to used to screen the list of measures. water supply. To gauge the effect of 2030 in population (19%) and • Does the product (water-using the plumbing codes and natural fixture employment (31%) shift the water fixture) work well, and is it readily replacement, each DSS model was use percentages by customer-billing available?

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LEVIN ET AL | PEER-REVIEWED | 98:2 • JOURNAL AWWA | FEBRUARY 2006 107 as part of the water demand–pro- FIGURE 6 Percentage breakdown of SFPUC wholesale customer water jections study as described previ- consumption by customer billing category ously and by URS (2004a). To evaluate each conservation measure in the individual wholesale customer- Other 16 Single-family service areas, it was necessary to 42 determine the potential “market” Industrial 9 within which the conservation measure could be implemented. The applicable market for each of 32 conservation measures was based on Commercial the unique characteristics of each 17 service area. Data were collected for each wholesale customer’s service area, including number and types of toilets; number and size of large Multifamly 16 landscape areas (i.e., parks, school grounds, athletic fields, golf courses, SFPUC—San Francisco Public Utilities Commission and cemeteries); number of hotels/ Projected year 2030; “other” category includes miscellaneous, institutional, municipal, motels and number of rooms; num- and irrigation/landscape uses where these water uses are metered separately. ber of dine-in restaurants; and number of coin-operated laundries; among others. The data were used to FIGURE 7 Example of present value of utility costs versus water saved determine the market for each conservation measure. 0.6 In addition to the data collected, assumptions were also made about 0.5 water use for particular usage cate-

mgd gories within the wholesale cus- Program C 0.4 Program B tomers’ service area, such as the Program A amount of commercial water used 0.3 by hotels or the average amount of Plumbing codes irrigable land per park, school, and 0.2 commercial site, for example. This information was also used 0.1

Cumulative Water Saved— to estimate the total cost of implementing conservation measures. For 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 example, knowing the number of hotel rooms in a wholesale cus- Value—$ millions tomer’s service area allows costs to 30-year analysis from 2001 be developed for a conservation measure that retrofits a certain number of hotel rooms in that area. • Would the measure have wide- to evaluate the cost-effectiveness of Costs are further discussed later in spread application in the Bay Area? each of the 32 measures and the cost- this article. • Will the retail customer partic- effectiveness of three different pack- In addition to examining the mar- ipate in the measure or use the prod- ages of the measures (conservation ket potential for each measure, the uct, and is the measure applied fairly programs) for each wholesale cus- project team identified several vari- to the different customer types? tomer. The model also yielded a range ables associated with cost and imple- • Among similar measures that of water savings associated with pro- mentation of each conservation mea- accomplish the same objective, is this gram implementation over a 30-year sure, including the best one? planning period. • targeted water use, Thirty-two conservation measures The conservation-potential eval- • the market penetration goal for passed the qualitative screening and uation used the same service-area- a measure, made up the final list (see sidebar on specific, calibrated, end-use water • potential water savings from page 105). The DSS model was used demand DSS models that were used implementing a measure,

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108 FEBRUARY 2006 | JOURNAL AWWA • 98:2 | PEER-REVIEWED | LEVIN ET AL TABLE 1 Example summary of SFPUC conservation evaluation results by measure

Water Utility Cost Cost Utility Customer Annual of Savings Net to Utility Conservation Benefit– Benefit– Water per Unit Utility for First Measure Cost Cost Savings* Volume Benefit 5 Yrs Number Ratio Ratio mgd $/mil gal $† $

Residential water surveys, 1 0.7 1.3 0.182 1,117 (728,051) 582,863 Large landscape conservation, 3 0.7 0.6 0.085 1,125 (371,822) 308,092 Clothes washer rebate, 5 1.2 2.1 0.058 689 78,689 482,097 Commercial water audits, 7 1.6 2.1 0.227 480 698,967 742,507 Residential ULFT rebate, 9 0.5 0.2 0.503 1,475 (4,005,159) 5,155,240 Rebates for 6/3 dual flush or 4-L toilets, 12 0.8 0.6 0.467 908 (769,295) 2,778,748 ET controller rebates, 13 0.5 0.4 0.092 1,343 (657,871) 450,424 Incentives for retrofitting submetering, 18 1.7 1 0.016 444 57,097 46,853 Financial incentives for irrigation upgrades, 30 1.3 0.7 0.006 562 10,018 11,074

ET—evapotranspiration, SFPUC—San Francisco Public Utilities Commission, ULFT—ultralow-flow toilet

*30-year average. †Results shown in parentheses indicate a negative value.

• length of time the measure is BENEFITS AND COSTS • Annual water savings, averaged implemented to reach desired mar- ANALYZED over the 30-year planning period and ket penetration, The DSS model output presents expressed in million gallons per day. • length of time the water sav- how much water the measures would • Annual utility administration ings will last from implementing a save, how much each measure would costs, payment of rebates, or pur- measure, cost to implement, and the bene- chases of devices or services as spec- • costs associated with implement- fit–cost ratios that would result if the ified in the measure design. Cost can ing the conservation measure, and measures were run on a stand-alone be expressed as present value, as first • measurement of savings decay. basis (i.e., without interaction or five years of estimated costs, and as Using these data, the DSS model overlap from other measures that cost per unit water saved (in dollars estimates the potential for future might address the same end use or per million gallon). water savings and calculates associ- uses). Benefits and costs for selected ated costs and benefits of the con- measures using an example SFPUC POTENTIAL CONSERVATION servation measures and programs wholesale customer are summarized PROGRAMS DEVELOPED through the following key steps: in Table 1 and include To identify the range of water con- • calculating the water savings • Benefits and costs that the util- servation savings that are reasonable for each year in which the measure is ity would receive or spend. and cost-effective, the conservation implemented using the end-use esti- • Utility–customer benefits and measures were grouped together into mates from the water demand fore- costs, which encompass the sum of util- programs. Each wholesale customer casting, additional service area char- ity benefits plus retail customer energy selected measures based on the fol- acteristics, the unit water savings, benefits (cost to heat water), and the lowing factors: cost-effectiveness of and the projected market penetra- sum of utility and retail customer costs. the individual measure; potential tion associated with each measure, • Water savings benefits based on water savings for individual mea- • calculating the cost of the mea- assigning a typical unit value for sures; service-area water use charac- sure for each year of implementation avoided cost of water. In this in- teristics; retail customer behavioral based on the unit costs and the num- stance, a cost of $3,033/mil gal was patterns; budgetary considerations; ber of participating accounts, and utilized for SFPUC purchases, at the and ease of implementation. To • computing the benefits to the time reflecting the commission’s most account for any overlap in water sav- wholesale customer based on the recent reporting on the cost of water ings and benefits and provide esti- water savings accumulated for each in 2015 following implementation mates of combined savings and ben- year of implementation. of the WSIP. Those wholesale cus- efits, a DSS model evaluation for each The benefits calculated for this tomers with alternate supplies were of the three programs was completed. study include avoided cost of water given the option to utilize a blended In general, the programs con- and reduced hot water use. cost of water for 2015. tained between 5 and 15 measures.

LEVIN ET AL | PEER-REVIEWED | 98:2 • JOURNAL AWWA | FEBRUARY 2006 109 TABLE 2 Evaluation results for SFPUC wholesale customer service area conservation program

Water Water 2030 Total Utility Utility 2030 Outdoor Cost Potential 2030 Benefit– Costs, Present Water Water of Water Water Conservation Cost Value* Savings† Savings† Saved* Savings Program Ratio* $1,000 mgd mgd $/mil gal mgd

Plumbing code‡ NA NA NA NA NA 25.4 Program A 1.95 62,601 7.65 3.52 860 33.1§ Program B 2.35 93,385 14.53 7.77 720 40.0** Program C 2.50 117,866 19.59 10.56 690 45.0††

NA—not applicable, SFPUC—San Francisco Public Utilities Commission

*Over a 30-year period. †Resulting from conservation programs. ‡Plumbing code savings are not a conservation program, but represent water use savings associated with the natural replacement of plumbing fixtures with water- efficient models (i.e., toilets, showerheads, or washing machines). §Includes plumbing code savings and savings from program A **Includes plumbing code savings and savings from programs A and B ††Includes plumbing code savings and savings from programs A, B, and C

TABLE 3 Conservation savings as a percentage of total new demand for SFPUC wholesale customer service area

2001 DSS 2030 DSS Base Year Projected 2030 Water Savings§ Water Savings** Customer Water Water 2030 mgd % Service Demand* Demand† New Area mgd mgd Demand‡ A B C A B C

SFPUC wholesale 272 324 52 7.65 14.53 19.59 15 28 38

DSS—decision support system, SFPUC—San Francisco Public Utilities Commission

*URS, 2004a †Includes plumbing code savings ‡Demand increase from 2001 §Resulting from conservation programs **As a percentage of 2031 new demand

The programs were structured so that spent over time. A comparison of the expenditure. In general, as more program A reflected what the cus- the cumulative costs of the programs conservation measures are added, a tomers were implementing or plan- over a 30 year timespan from pro- point is reached beyond which the ning to implement in the immediate gram A to C (including the plumbing water savings increase only margin- future; program B contained pro- code) with the additional water sav- ally in response to spending more gram A plus additional measures con- ings achieved is useful for evaluat- money. For the example wholesale sidered to be implementable in the ing whether adding measures in pro- customer shown in Figure 7, mov- future; and program C contained grams B and C is cost-effective. ing from program B to program C is programs A and B plus additional Figure 7 shows this relationship for not cost-effective. measures representing the full extent an example wholesale customer and of measures that appeared to be includes baseline plumbing code sav- CONSERVATION EVALUATION implementable and cost-effective. The ings in addition to savings associ- RESULTS EXAMINED three programs define the range of ated with programs A, B, and C after The results of the SFPUC whole- conservation that appeared to be rea- 30 years. The slope of the line sale service area conservation poten- sonable and cost-effective for each between the programs is indicative of tial evaluation are published in wholesale customer. The programs the cost-effectiveness of moving to another URS Corporation report, are not intended to be rigid but rather the next increasing program. For SFPUC Wholesale Customer Water to demonstrate the range in savings example, if the slope of the line is Conservation Potential (2004b). that could be generated if selected flat, the water savings are small com- Tables 2 and 3 summarize the con- measures were run together. pared with the amount of money servation evaluation results tabulated Figure 7 illustrates the increasing spent. If the slope of the line is steep, for the entire wholesale customer- level of water savings for money the savings are great compared with service area. As the tables show, the

110 FEBRUARY 2006 | JOURNAL AWWA • 98:2 | PEER-REVIEWED | LEVIN ET AL range in potential water savings in how much water they plan to pur- ABOUT THE AUTHORS 2030 in the wholesale customer-ser- chase from the commission. Ellen R. Levin vice area is approximately 7.7–19.6 The individual wholesale cus- (to whom mgd, in addition to about 25.4 mgd tomers, SFPUC and BAWSCA, have correspondence savings gained from the existing used the results of the conservation should be plumbing codes. Table 3 illustrates evaluation in multiple ways. The addressed) is the that this corresponds with a range SFPUC requested that the individual director of of approximately 15–38% in water wholesale customers and SFPUC retail water resources savings as a percent of 2030 demand customers, as a group, provide a 2030 and supply at increase from 2001 (i.e., new water projection of purchases from the com- SFPUC, 1145 Market Street, Ste. needed to accommodate planned mission’s regional water system. In 401, San Francisco, CA 94103; e- growth across the wholesale cus- making their purchase projections, mail [email protected]. She has a tomer-service area). the customers considered the results BS in conservation and resource As one can deduce from Table 2, of the conservation evaluation studies from the College of Natural about half the conservation program because it quantified potential con- Resources at the University of Cali- savings accrue from indoor water use servation savings that could be con- fornia at Berkeley and an MS in reduction. The indoor water use sav- sidered an additional source of supply. land resources from the Institute ings are in addition to to the savings SFPUC is also using the information for Environmental Studies at the resulting from the plumbing codes. to investigate developing a financial University of Wisconsin in Madi- The programs have an overall bene- incentives program that encourages son. In 1998, she was awarded a fit–cost ratio of 1.95–2.5 to 1, ren- the use of recycled water and the fellowship from the US Environ- dering them cost-effective. The cost of implementation of conservation mea- mental Protection Agency’s water saved, ranging from $690 to sures to increase the regional water National Network for Environ- $860/mil gal is lower than the current system’s supply reliability. mental Management Studies. Dur- cost of SFPUC water and consider- This study is one of the largest ing her 5-year tenure with the ably lower than the future projected water demand forecasting and con- SFPUC, she represented the com- cost of SFPUC water. The costs for servation evaluation projects that mission’s wholesale interests at the achieving these water savings are con- has been undertaken in the United California Urban Water Conserva- siderable, however, ranging from a States. More than 100 people tion Council before becoming present value of about $60 million– worked on the project for 2 years. involved in resources planning and $120 million over the 30-year study The end result is a wholesale cus- policy analysis in her current posi- period. tomer service area range of conser- tion. Bill O. Maddaus is the princi- vation potential savings through pal of Maddaus Water Manage- RESULTS USED IN MULTIPLE WAYS 2030. This is for SFPUC use in long- ment in Alamo, Calif. Nicole M. Understanding future water term regional water system planning, Sandkulla is a senior water demand, including demand manage- solidified through individual whole- resources engineer for Bay Area ment potential through water con- sale customer participation and con- Water Supply and Conservation servation programs, is an important currence of results. Agency in San Mateo, Calif., and aspect in planning for wholesale Heather Pohl is an engineering pro- water system reliability improve- ACKNOWLEDGMENT ject manager at the URS Corpora- ments. The results of this study help The authors offer special thanks to tion in Oakland. the SFPUC to make long-term re- all the SFPUC wholesale customers gional water system planning deci- for their contributions and commit- FOOTNOTES 1The Wholesale Water Agency Assistance Pro- sions and enable wholesale customers ment to this project. The success of grams require wholesale water agencies such as to better assess their options for meet- this project would not have been pos- the SFPUC to provide technical and/or financial assistance to its wholesale customers. ing future water needs and deciding sible without their support. 2Maddaus Water Management, Alamo, Calif.

REFERENCES BAWUA (Bay Area Water Users Association), 2002. Bay Area Water Users Association Annual Survey, FY 2001–02, December. BAWUA, San Francisco. URS Corporation, 2004a. SFPUC Wholesale Customer Water Demand Projections. Technical report. URS, San Francisco. If you have a comment about this URS Corporation, 2004b. SFPUC Wholesale Customer Water Conservation Potential. Technical article, please contact us at report. URS, San Francisco. [email protected].

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