Revised Water Supply Assessment — CleanPowerSF Sfpuc Commission, October 24, 2023

AGENDA ITEM
Public Utilities Commission
City and County of San Francisco

DEPARTMENT Water Enterprise
AGENDA NO.

7 MEETING DATE

October 24, 2023

Approve Water Supply Assessment: Regular Calendar
Project Manager: Paula Kehoe

Approve Revised Water Supply Assessment for the 3251 20 th Avenue (Stonestown) Project

Summary of
Proposed
Commission
Action:

Approve the Revised Water Supply Assessment for the proposed 3251 20 th Avenue (Stonestown) Project, pursuant to the State of California Water Code Section 10910, et seq. , California Environmental Quality Act (CEQA) S ection 21151.9, and CEQA Guidelines Section 15155.

Background: California’s Water Supply Assessment law (California Water Code (Water Code) Sections 10910-10915) provides a nexus between the regional land use planning process and the environmental review process. The law also reflects the growing awareness of the need to incorporate water supply and demand analysis at the earliest possible stage in the land use planning process. The core of this law is the requirement for a public water system, such as the San Francisco Public Utilities Commission (SFPUC),
to prepare a Water Supply Assessment (WSA) of
whether available water supplies are sufficient to serve the demand generated by projects of a specified size (water demand projects), as well as the reasonably foreseeable cumulative demand in the region over the next 20 years under a range of hydrologic conditions. The WSA, as explained bel ow, is subject to Commission approval.

The San Francisco Planning Department, which carries out the City’s lead agency responsibilities under CEQA, is preparing an Environmental Impact Report for the proposed 3251 20 th Avenue (Stonestown) Project, which would redevelop approximately 27 acres surrounding the existing Stonestown Galleria shopping mall into a master -planned, multi -phased, mixed- used residential and retail community in the Lakeshore area of southwest San Francisco. T he Project would include up to approximately 2,930 residential units; up to 160,000 square feet (sf) of new retail sales and service use space; up to 200,000 sf of new non- retail sales and service use; up to approximately 100,000 sf of hotel use; approximately 53,000 sf of institutional uses; approximately 4,250 parking spaces; 6 acres of open space; and infrastructure improvements.

One variant
would include development of the 0.8- acre parcel that is currently occupied by Authentic Church into an additional 561 residential units (3,491 residential units total); 104,000 sf less non- retail sales and service use (up to 96,000 sf total); additional 611 parking spaces (4,861 spaces total); and no hotel use.

The Planning Department identified the 3251 20th Avenue (Stonestown) Project Agenda Title: Approve Revised Water Supply Assessment for the 3251 20th Avenue (Stonestown) Project Commission Meeting Date: October 24, 2023

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as a water demand project, qualifying for the preparation of a WSA, because it is a mixed-use residential development that would include more than 500 dwelling units.

The content of a WSA is specified by the Water Code and includes identification of any existing water supply entitlements or contracts and detailed information about groundwater supplies. It assesses the adequacy of water supplies to serve the proposed project and cumulative demand.

The WSA must be completed by the public water supplie r that would serve the proposed project and be approved by its governing body at a public meeting.

Approval of a WSA is not approval of the development project for which the WSA is prepared. A WSA is an informational document required to be prepared for use in the City’s environmental review of a proposed project under CEQA.

The 3251 20
th Avenue (Stonestown) Project has already been accounted for in SFPUC’s water supply planning as described in the 2020 Urban Water Management Plan.

Furthermore, the SFPUC prepared an interim set of retail water demand projections to account for housing unit projections associated with the Housing Element 2022 Update. The Housing Element 2022 Update Environmental Impact Report, which supported the City’s adoption of the Housing Element in January 2023, assumed slightly higher housing unit projections than those used in the 2020 UWMP. Because the 3251 20
th Avenue (Stonestown) Project has already
been accounted for in the 2020 U rban W ater Management Plan, the Project is also accounted for in the 2023 Interim Water Demand Projections.

On October 24, 2022, by Resolution No. 22-0186, this Commission approved a WSA for this project. Staff has prepared the attached Revised WSA to account for (1) revisions to the proposed project variant resulting in additional residential units, less non-retail sales and service use, and no hotel use and (2) updates to the SFPUC’s projected total retail water demands associated with the adopted Housing Element 2022 Update . If a pproved by the Commission, the R evised WSA would supersede the previous WSA prepared for the proposed project.

The Revised WSA analyzes the sufficiency of long -term water supplies to serve the proposed proj ect and cumulative development over a 20- year projection. On December 12, 2018, the State Water Resources Control Board adopted amendments to the Water Quality Control Plan for the San Francisco Bay/Sacramento-San Joaquin Delta Estuary (Bay-Delta Plan Amendment). If the Bay-Delta Plan Amendment were to be implemented, it would result in significant water supply shortages during single dry and multiple dry years. The City, along with multiple other water agencies, filed suit in early 2019 challenging the validity of the Bay- Delta Plan Amendment. That lawsuit, which is consolidated with the other legal challenges, is currently pending in Sacramento Superior Court. Since 2019, SFPU C has participated in negotiations with the State and other stakeholders regarding a voluntary agreement that could ultimately be adopted as an alternative or substitute for the Bay - Delta Plan
Amendment. On March 1, 2019, in accordance with the State Water Resources Agenda Title: Approve Revised Water Supply Assessment for the 3251 20th Avenue (Stonestown) Project Commission Meeting Date: October 24, 2023

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Control Board’s instruction, SFPUC submitted to the State a proposed voluntary agreement (Proposed Voluntary Agreement) . On November 9, 2022, SFPUC signed a non- binding Memorandum of Understanding with various representatives of the State enviro nmental and resource agencies, outlining conceptual deal points for a Tuolumne River Voluntary Agreement. As of the date of this report, the Memorandum of Understanding remains in effect and the Voluntary Agreement negotiations are ongoing.

For these and other reasons described more fully in the attached Revised WSA and in the 2020 U rban Water Management Plan, whether the Bay -Delta Plan Amendment or the Proposed Voluntary Agreement will be implemented in the future is currently uncertain. Thus, the Revised WSA analyzes three scenarios:

1. S cenario 1 : No implementation of the Bay -Delta Plan Amendment or the Proposed Voluntary Agreement

2. Scenario 2: I mplementation of the Proposed Voluntary Agreement

3. Scenario 3: Implementation of the Bay-Delta Plan Amendment

The Revised WSA concludes that:

• During normal years, the SFPUC’s total projected water supplies will meet the projected demands of its retail customers, including those of the proposed project, existing customers, and foreseeable future development under Scenario 1, Scenario 2, and Scenario 3.
• D
uring single dry years and multiple dry years under Scenario 1 , the SFPUC can meet the projected demands of its retail customers, including those of the proposed project, existing customers, and foreseeable future development without the need for water use reduction beyond the level of service (LOS) goal of 20% system-wide water use reduction. • During single dry years and multiple dry years under Scenario 2, t he
SFPUC would still face a shortfall in single dry and multiple dry years, thus requiring water use reduction, but to a lesser degree and in closer alignment to the LOS goal of no more than 20% system-wide water use reduction compared to that which would occur under Scenario 3. Because negotiations in furtherance of the November 9, 2022 Voluntary Agreement Memorandum of Understanding continue in earnest, and litigation challenging the adoption of the Bay-Delta Plan Amendment remains pending, supply and demand that would result under Scenario 2 are more likely to occur than those projected in Scenario 3. • During single dry years and multiple dry years under Scenario 3, t he
SFPUC cannot reliably meet the projected demands of its retail customers, including the proposed project, existing customers, and foreseeable future development, without water use reduction at a level greater than that required to achieve the LOS goal of a maximum of 20% system-wide average water use reduction starting as soon as 2022. The SFPUC estimates it would impose up to 36% water use reductions across Agenda Title: Approve Revised Water Supply Assessment for the 3251 20th Avenue (Stonestown) Project Commission Meeting Date: October 24, 2023

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the retail service area.
• The SFPUC’s 2020 Water Shortage Contingency Plan describes allocation methods and processes that may be used in future droughts. For both residential and commercial customers, the SFPUC may implement varying levels of water use reductions based on the baseline level of water use, e.g. require less reduction from customers that use less water to begin with. For the proposed project specifically, these policies may result in lower levels of mandatory water use reduction as a result of the installation of water-efficient plumbing fixtures and non-potable water systems associated with new construction.
• Under Scenario 3, the relatively small volume of water demand generated by the proposed project itself would not exacerbate the projected shortfalls resulting from implementation of the Bay-Delta Plan Amendment. Regardless of whether the proposed project is constructed, with implementation of the Bay-Delta Plan Amendment, the SFPUC’s existing and planned water supplies will not meet the water demands of its retail service area in dry years without significant demand reductions.

Environmental
Review:

Approval of the Revised Water Supply Assessment is not considered approval of a project as defined in Section 15378 of the CEQA Guidelines. The Revised Water Supply Assessment is required by and prepared according to the CEQA Guidelines and is an informational document only. Approval of the Revised Water Supply Assessment does not constitute the Commission’s approval of the proposed 3251 20th Avenue (Stonestown) Project.

The Planning Department’s case number for this proposed project is 2021 - 012028ENV.

Attachment: 1. Revised Water Supply Assessment for t he 3251 20 th Avenue (Stonestown) Project

PUBLIC UTILITIES COMMISSION
City and County of San Francisco

RESOLUTION NO.

WHEREAS, Under the California Environmental Quality Act (CEQA) and California Water Code Section 10910(g)(1), the San Francisco Public Utilities Commission (SFPUC) is required to prepare and approve a Water Supply Assessment (WSA) for the cumulative water demands presented by the proposed 3251 20 th Avenue (Stonestown) Project, which would redevelop approximately 27 acres surrounding the existing Stonestown Galleria shopping mall into a master -planned, multi -phased, mixed- used residential and retail community in the Lakeshore area of southwest San Francisco; and
WHEREAS, The 3251 20 th Avenue (Stonestown) Project is required to comply with the City’s Non-potable Water Ordinance, Article 12C of the San Francisco Health Code, and as a result, the Project will offset its potable water use through the use of alternate water sources; and
WHEREAS, A WSA is an informational document that assesses the adequacy of water supplies to serve a proposed project and is required to be prepared as part of the CEQA environmental review process; and
WHEREAS, The water demand associated with the 3251 20
th Avenue (Stonestown)
Project is encompassed within the 2020 Urban W ater Management Plan water demand projections; and
WHEREAS, The water demand associated with the 3251 20 th Avenue (Stonestown) Project is also encompassed within the 2023 Interim Water Demand Projections, which the SFPUC prepared after the 2020 Urban Water Management Plan water demand projections to account for slightly higher housing unit projections associated with the Housing Element 2022 Updated adopted by the City in January 2023; and
WHEREAS, Approval of a WSA as an informational document is not considered an approval action as defined in section 15378 of the CEQA Guidelines; and WHEREAS, A WSA must be approved at a public meeting by the governing body of the public water supplier that would serve the proposed project; and WHEREAS, On October 24, 2022 by Resolution No. 22-0186, this Commission approved a WSA for the 3251 20
th Avenue (Stonestown) Project, which concluded that the SFPUC has adequate water supplies to meet the proposed project’s water demands through 2040; and
WHEREAS, Following this Commission’s approval of the WSA, the SFPUC updated its project total retail water demand projections to account for the adopted Housing Element 2022 Update; and
WHEREAS, Following this Commission’s approval of the WSA, the project description was revised to include more residential units, less non- retail sales and service use, and no hotel, resulting in higher water demand estimates for the current proposed project compared to those provided in the WSA approved on October 24, 2022; and

WHEREAS, The SFPUC staff prepared the attached Revised WSA for the proposed 3251 20 th Avenue (Stonestown) Project, analyzing water supply and demand under three scenarios: (1) No implementation of the Bay -Delta Plan Amendment or the Proposed Voluntary Agreement (Scenario 1), (2) Implementation of the Proposed Voluntary Agreement (Scenario 2), and (3) Implementation of the Bay-Delta Plan Amendment (Scenario 3); and WHEREAS, The Revised WSA concludes that the SFPUC ’s total projected water supplies through 2045 will (1) meet the demands of the proposed project in normal years under all three scenarios, (2) meet the demands of the proposed project in dry years without rationing beyond the SFPUC’s level of service ( LOS) goal of no more than 20% system -wide rationing under Scenario 1, (3) meet the demands of the proposed project in dry years but require rationing closer to the LOS goal under Scenario 2, and (4) not reliably meet the demands of the proposed project without rationing at a level greater than tha t required to achieve the LOS goal under Scenario 3; and
WHEREAS, In dry years, the proposed project may have lower levels of mandatory water use reduction compared to existing buildings because of the installation of water- efficient plumbing fixtures and non- potable water systems associated with new construction, and the relatively small volume of water demand generated by the proposed project itself would not exacerbate the projected shortfalls resulting from implementation of the Bay -Delta Plan Amendment; now, therefore, be it
RESOLVED, This Commission approves the attached Revised Water Supply Assessment for the proposed 3251 20
th Avenue (Stonestown) Project pursuant to California
Water Code Section 10910(g).

I hereby certify that the foregoing resolution was adopted by the Public Utilities Commission at it’s meeting of October 24, 2023.

Secretary, Public Utilities Commission

OUR MISSION: To provide our customers with high-quality, efficient and reliable water, power and sewer services in a manner that values environmental and community interests and sustains the resources entrusted to our care.
525 Golden Gate Avenue, 13th Floor
San Francisco, CA 94102
T 415.554.3155
F 415.554.3161
TTY 415.554.3488
Septembe
r 26, 2023
TO: C
ommissioner Newsha K. Ajami, President
Commissioner Sophie Maxwell, Vice President
Commissioner Tim Paulson
Commissioner Anthony Rivera
Commissioner Kate H. Stacy
THRO
UGH: Dennis J. Herrera, General Manager
FROM: S
teven R. Ritchie, Assistant General Manager, Water
RE: Revi
sed Water Supply Assessment for the 3251 20th Avenue
(Stonestown) Project
Summary
Introduction
The California Water Code (Sections 10910 through 10915) requires urban water suppliers like the San Francisco Public Utilities Commission (SFPUC) to furnish a Water Supply Assessment (WSA) to the city or county that has jurisdiction to approve the environmental documentation for certain qualifying projects (as defined in W ater Code Section 10912(a)) subject to the California Environmental Quality Act (CEQA).

The WSA process typically relies on inf ormation contained in a water supplier’s Urban Water Management Plan (UWMP) and involves answering specific questions related to the estimated water demand of the proposed project. This memo serves as the WSA for the proposed 3251 20th Avenue (Stonestown) Project (proposed project), for use in the preparation of an environmental impact report by t he San Francisco Planning Department (case no. 2021-012028ENV, San Francisco Planning Department).

This WSA is a revision to and supersedes the WSA that was previously prepared for the same proposed project dated September 29, 2022 and approved on October 24, 2022 (Resolution No. 22-0186). This WSA was revised to account for (1) revisions to the
proposed project variant resulting in additional residential units, less non-retail sal
es and service use, and no hotel use compared to the original variant; and (2) recent changes to San Francisco retail water demand projections reflecting the adopted Housing Element 2022 Update described in the next section.

1.1.1 20 20 Urban Water Management Plan and 2023 Interim Water Demand Projections
The Commission, by Resolution No. 21-0100, adopted the SFPUC’s current 2020 UWMP. The water demand projections in the UWMP incorporated housing unit growth projections from the Housing Element 2022 Update objective and employment growth projections from the 2017 Land Use Allocation (LUA 2017); San Francisco Planning Department provided both projections. Since the SFPUC’s adoption of the 2020 UWMP in June 2021, the Planning Commission certified the Housing Element 2022 Update Environmental Impact Report (Housing Element EIR) in November 2022. The Housing Element EIR, which supported the City’s adoption of the Housing Element in January

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Revised WSA for 3251 20th Avenue (Stonestown) Project
September 26, 2023

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2023, assumed slightly higher housing unit projections than those used in the 2020 UWMP, but was still in line with the objective to produce an average of 5,000 housing units per year. Nonetheless, as a result of the slightly higher housing unit projections associated with the Housing Element EIR, the SFPUC determined that its 2020 UWMP no longer accounted for all projected retail water demands.

The SFPUC will not be updating its UWMP until 2025. Therefore, during this interim period, the SFPUC has prepared the 2023 Interim Water Demand Projections (Attachment A) to document the SFPUC’s projected retail water supplies when compared to projected retail water demands associated with the adopted Housing Element 2022 Update. The San Francisco Planning Department provided the updated housing unit projections for SFPUC to update its water demand projections. The water demand projections are presented in five-year increments through 2045, meeting Water Code requirements.

Growth associated with the proposed project was encompassed within the growth projections used in the 2020 UWMP, and therefore encompassed within the updated growth projections used in the 2023 Interim Water Demand Projections. Consequently, water demand associated with the proposed project was encompassed within the water demand projections in the 2020 UWMP, and therefore encompassed within the 2023 Interim Water Demand Projections. In other words, the proposed project has already been accounted for in SFPUC’s water supply planning.

The WSA for a qualifying project within the SFPUC’s retail service area 1 may use information from the UWMP and, as applicable, the 2023 Interim Water Demand Projections. Therefore, the 2020 UWMP and 2023 Interim Water Demand Projections are incorporated by reference throughout this WSA, as shown in bold, italicized text. The 2020 UWMP and 2023 Interim Water Demand Projections may be accessed at www.sfpuc.org/uwmp.

As described in detail in Section 7.3.1 of the UWMP, in December 2018, the State Water Resources Control Board (SWRCB) adopted amendments to the Water Quality Control Plan for the San Francisco Bay/Sacramento-San Joaquin Delta Estuary (Bay- Delta Plan Amendment). The City, along with multiple other water agencies, filed suit in early 2019 challenging the validity of the Bay-Delta Plan Amendment. That lawsuit, which is consolidated with other legal challenges, is currently pending in Sacramento Superior Court. In January 2021, the SWRCB moved to implement the Bay-Delta Plan Amendment on the Tuolumne River by issuing a water quality certification under Section 401 of the Clean Water Act in the Federal Energy Regulatory Commission (FERC) licensing proceedings for the hydropower projects associated with the New Don Pedro and La Grange dams. The City and other water users on the Tuolumne River have filed pending legal and administrative challenges to these SWRCB actions.

FERC has not yet reissued a license for the New Don Pedro Hydropower Project, and the legal challenges to the water quality certification are pending and remain unresolved. Alongside the water quality certification, on August 8, 2022, the SWRCB issued a CEQA Notice of Preparation for an alternative means of implementing the Bay-Delta Plan Amendment.

Recognizing the obstacles to implementing the Bay-Delta Plan Amendment, the SWRCB, by Resolution No. 2018-0059 adopting the Bay-Delta Plan Amendment, directed staff to help complete a “Delta watershed-wide agreement, including potential flow measures for the Tuolumne River” by March 1, 2019, and to incorporate such

1 SFPUC’s “retail service area” refers to water customers inside the City and County of San Francisco (City), as well as select areas outside of the City.

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agreements as an “alternative” for a future amendment to the Bay-Delta Plan to be presented to the SWRCB “as early as possible after December 1, 2019.” In accordance with the SWRCB’s instruction, on March 1, 2019, the SFPUC, in partnership with other key stakeholders, submitted a proposed project description for the Tuolumne River that could be the basis for a voluntary substitute agreement with the SWRCB (Proposed Voluntary Agreement). Since 2019, SFPUC has participated in negotiations with the State and other stakeholders regarding the Proposed Voluntary Agreement. On November 9, 2022, SFPUC signed a non-binding Memorandum of Understanding with various representatives of the State environmental and resource agencies, outlining conceptual deal points for a Tuolumne River Voluntary Agreement. As of the date of the issuance of this Water Supply Assessment, those negotiations remain ongoing.

Implementation of the Bay-Delta Plan Amendment is uncertain given the ongoing negotiations, litigation, and regulatory proceedings; these are further described in Section 7.3.1 of the UWMP. Given the current uncertainty regarding the extent and timing of the implementation of the Bay-Delta Plan Amendment, this WSA analyzes water supply and demand through 2045 under three scenarios: (1) No implementation of the Bay-Delta Plan Amendment or the Proposed Voluntary Agreement (Scenario 1), (2) Implementation of the Proposed Voluntary Agreement (Scenario 2), and (3) Implementation of the Bay-Delta Plan Amendment (Scenario 3).

1.1.2 Basis for Requiring a WSA for the Proposed Project Except for the WSA approved on October 24, 2022 (Resolution No. 22-0186), which is superseded by this revised WSA, the proposed project has not been the subject of a previous WSA, nor has it been part of a larger project for which a WSA was completed.

The proposed project qualifies for preparation of a WSA under Water Code Section 10912(a) because it is a mixed-use residential development that includes more than 500 dwelling units. The proposed project is characterized further in Section 1.2.

1.2 Proposed Project Description
The proposed project is located on an approximately 41-acre site in the Lakeshore area in southwest San Francisco. The project sponsor (Brookfield Properties Development) proposes to redevelop the approximately 27 acres surrounding the existing on-site Stonestown Galleria shopping mall into a master-planned, multi- phased, mixed-use residential and retail community. Under the proposed project, the existing 760,000-square-foot (sf) Stonestown Galleria shopping mall would remain, with changes to the façade, entrances, and exits. The existing parking garage in the southwest corner of the project site, the vacant theater at the northwest corner of the site, and the CitySports and commercial building at the northeast corner of the site would be demolished and redeveloped as part of the proposed project.

Overall, the proposed project would include up to approximately 2,930 residential units; up to 160,000 sf of new retail sales and service use space; up to 200,000 sf of new non-retail sales and service use; up to approximately 100,000 sf of hotel use; approximately 53,000 sf of institutional uses to include an approximately 15,000- square-foot childcare facility and space for community use; approximately 4,250 parking spaces; 6 acres of open space; and infrastructure improvements.

One variant to the proposed project is also under consideration, which would include the development of the 0.8-acre parcel that is currently occupied by Authentic Church at 3355 19
th Avenue, adjacent to the project site between Eucalyptus and Winston drives. Under the variant, the redevelopment of the 27 acres surrounding the Stonestown Galleria would be the same as the proposed project; however, the Memo to Commissioners
Revised WSA for 3251 20th Avenue (Stonestown) Project
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additional 0.8-acre Authentic Church parcel would be developed with an additional 561 residential units (3,491 residential units total); 104,000 sf less non-retail sales and service use (up to 96,000 sf total); additional 611 parking spaces (4,861 spaces total); and no hotel use.

For the purpose of the WSA, only the variant is assessed for water supply as it would result in a higher water demand estimate and would encompass the proposed project demands. Refer to Attachment B for additional details on both the proposed project and variant. All subsequent references to the “proposed project” in this memo refer to the variant unless otherwise noted.

Project construction would occur in six phases over the course of approximately eight years, from 2024 to approximately 2032. The first operational year is assumed to be 2027. By 2030, construction of Phases 1 through 3 is assumed to be completed, consisting of up to approximately 1,893 residential units (1,867,500 sf), up to 66,000 sf of new retail sales and service use space; up to 12,000 sf of new non-retail sales and service use; and up to approximately 21,000 sf of institutional uses.

For additional details on the proposed project, see Attachment B.

2.0 Water Supply
This section reviews San Francisco’s existing and planned water supplies.

2.1 Regional Water System
See Section 3.1 of the UWMP for descriptions of the San Francisco Regional Water System (RWS), Section 6.1 of the UWMP for water rights held by City and County of San Francisco, and Section 7.1 of the UWMP for the SFPUC Water System Improvement Program (WSIP).

2.2 Existing Retail Supplies
Retail water supplies from the RWS are described in Section 6.1 of the UWMP.

Local groundwater supplies, including the Westside Groundwater Basin, are described in Section 6.2.1 of the UWMP.

Local recycled water supplies, including the Harding Park Recycled Water Project and Pacifica Recycled Water Project, are described in Section 6.2.1 of the UWMP.

2.3 Planned Retail Water Supply Sources
The San Francisco Groundwater Supply Project is described in Section 6.2.1.1 of the UWMP.

The Westside and Treasure Island Recycled Water Projects are described in Section

6.2.2 of the UWMP.

2.4 Summary of Current and Future Retail Water Supplies A breakdown of water supply sources for meeting SFPUC retail water demand through 2045 in normal years is provided in Section 6.2.5 of the UWMP. For dry years, see the next section.

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2.5 Dry-Year Water Supplies
A description of dry-year supplies developed under WSIP is provided in Section 7.2 of the UWMP.

2.6 Additional Water Supplies
The SFPUC is increasing and accelerating its efforts to acquire additional water supplies and explore other projects that would increase overall water supply resilience through the Alternate Water Supply Program. A description of the Alternative Water Supply Program and the supplies being studied is provided in Section 7.4 of the UWMP.

3.0 Water Demand
This section reviews the projected retail water demands and the demand associated with the proposed project.

3.1 Projected Retail Water Demand
The projected retail water demand through 2045 is described in Section 4.1 of the UWMP and updated in the 2023 Interim Water Demand Projections (Attachment A). This section of the UWMP also describes the methodology used for demand projections and the factors considered. Updates specific to the to the change in housing unit projections are described in the 2023 Interim Water Demand Projections.

3.2 Proposed Project Water Demand
The project sponsor’s consultants provided a memo describing the methods and assumptions used to estimate the water demand of the proposed project, along with the resulting demand (Attachment B).

Because the proposed project must comply with San Francisco’s Non-potable Water Ordinance (Article 12C of the San Francisco Health Code), estimates for both potable and non-potable demands were submitted as part of the WSA request. The Non- potable Water Ordinance requires new development projects with 100,000 square feet or more of gross floor area, that apply for a site permit after January 1, 2022, to install and operate an onsite non-potable water system. Commercial buildings must meet their toilet and urinal flushing and drain trap priming demands through the collection, treatment, and use of available blackwater and condensate. Residential and mixed-use buildings must meet their toilet and urinal flushing, irrigation, clothes washing, and drain trap priming demands through the collection, treatment, and use of available graywater and condensate. While not required, residential and mixed-use projects may use treated blackwater if desired. As indicated in the water demand memo provided on behalf of the project sponsor in Attachment B, the proposed project would exceed the requirements of the Non-potable Water Ordinance by also using non-potable water to meet heating and cooling demands, in additional demands for toilet and urinal flushing, irrigation, clothes washing, and drain trap priming.

Both potable and non-potable demands for the project were estimated using the SFPUC’s Non-potable Water Calculator and supplemented with additional calculations for heating and cooling demands and alternate estimates of persons per household.

The SFPUC reviewed the memo to ensure that the methodology is appropriate for the types of proposed water uses, the assumptions are valid and thoroughly documented along with verifiable data sources, and a professional standard of care was used. The SFPUC concluded that the demand estimates provided on behalf of the project Memo to Commissioners
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sponsor are reasonable. Water demand associated with the proposed project over the 20-year planning horizon is shown in the following Table 1.

The non-potable demand estimates in Table 1 are based on building uses anticipated at the time the WSA was requested, i.e., during the planning and environmental review stage of the proposed project. It is understood that these estimates will likely change as the proposed project’s design progresses, and information submitted for the WSA request is not part of the proposed project’s compliance with the Non-potable Water Ordinance. City review and approval of a proposed onsite water system must be performed separately through the Non-potable Water Program. However, the intent of providing a breakdown of potable and non-potable demand estimates in this WSA is to demonstrate that the proposed project will incorporate water reuse per City requirements and the proposed project’s sustainability goals, if any. As noted earlier, the total demand of the proposed project, regardless of non-potable use, is already encompassed in the 2023 Interim Water Demand Projections. Furthermore, total demand represents the most conservative estimate and accounts for back-up potable supplies that must be provided by the SFPUC in the event that non-potable supplies serving the proposed project are unavailable.

Table 1: Water Demand Based on Project Phasing (mgd)
2025 2030 2035 2040 2045
Potable Demand -- 0.103 0.191 0.191 0.191
Non-potable Demand -- 0.075 0.118 0.118 0.118
Total Demand -- 0.178 0.309 0.309 0.309
Potential Potable Water
Savings as Percentage of Total
Demand
-- 40% 38% 38% 38%
mgd = million gallons per day

Notes:

Total demand conservatively assumes that all demands are met with potable supplies.

The San Francisco Planning Department has determined that the proposed project is encompassed within the housing projections described in the Housing Element 2022 Update and the employment projections from LUA 2017, as indicated in the letter from the Planning Department to the SFPUC (Attachment A). Therefore, the demand of the proposed project is also encompassed within the San Francisco retail water demands that are presented in the 2023 Interim Water Demand Projections, which considers retail water demand based on the housing and employment projections provided by the Planning Department. The following Table 2 shows the demand of the proposed project relative to total retail demand.

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Table 2: Proposed Project Demand Relative to Total Retail Demand 2025 2030 2035 2040 2045
Total Retail Demand (mgd)1 71.3 73.0 75.0 77.9 81.1
Total Demand of Proposed
Project (mgd) -- 0.178 0.309 0.309 0.309
Total Demand of Proposed
Project as Percentage of
Total Retail Demand2 -- 0.24% 0.41% 0.40% 0.38%
Notes:

1. Retail water demands per Table 3 of the 2023 Interim Water Demand Projections.

2. The proposed project is accounted for in the housing and employment projections provided by the Planning Department; therefore, total demands associated with the proposed project are accounted for in the 2023 Interim Water Demand Projections.

4.0 Conclusion

4.1 Comparison of Projected Supply and Demand
For all scenarios presented here, local supplies (i.e., supplies not from the RW S) correspond to those in Table 6-5 of the UWMP. Procedures for determining RWS supply availability per the SFPUC’s Water Shortage Allocation Plan (WSAP) are described in Section 8.2.4 of the UWMP.

As explained previously in Section 3.2, water demands associated with the proposed project are already captured in the retail demand projections presented in the UWMP.

The proposed project is expected to represent up to 0.41% of the total retail water demand. Total retail demands correspond to those in Table 3 of the 2023 Interim Water Demand Projections and reflect both passive and active conservation, onsite water reuse savings, and water loss.

4.1.1 Scenario 1: No Implementation of the Bay-Delta Plan Amendment or the Proposed Voluntary Agreement
Table 3 below is adapted from Table 5 of the 2023 Interim Water Demand Projections and compares the SFPUC’s retail water supplies and demands through 2045 during normal year, single dry-, and multiple dry-year periods under Scenario 1.

As shown in Table 3, under Scenario 1 without implementation of the Bay-Delta Plan Amendment, existing and planned supplies would meet all projected RWS demands in all years. Even though system-wide shortages of RWS supplies would occur in the 4 th
and 5th years of a multi-year drought at 2045 projected levels of demand, retail customers would reduce their demands by 5% as required by the Water Supply Agreement between SFPUC and its Wholesale Customers. To achieve a small reduction such as this, the SFPUC may prohibit certain discretionary outdoor water uses and/or call for voluntary water use reduction by its retail customers pursuant to its Water Shortage Contingency Plan (Appendix K of the UWMP). The required level of water use reduction is well below the SFPUC’s RWS level of service (LOS) goal of limiting water use reduction to no more than 20% on a system-wide basis (i.e., an average throughout the RWS) in drought years. In 2008, by Resolution No. 08-0200, the Commission adopted this goal.

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September 26, 2023

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4.1.2 Scenario 2: Implementation of the Proposed Voluntary Agreement A Voluntary Agreement has yet to be accepted by SWRCB as an alternative to the Bay-Delta Plan Amendment and thus the shortages that would occur with its implementation are not known with certainty. However, given that the objectives of the Proposed Voluntary Agreement are to provide fishery improvements while protecting water supply through flow and non-flow measures, the RWS supply shortfalls under the Proposed Voluntary Agreement would be less than those under the Bay-Delta Plan Amendment, and therefore would require water use reductions of a lesser degree than that which would occur under Scenario 3. The degree of water use reduction would also more closely align with the SFPUC’s RWS LOS goal of limiting water use reduction to no more than 20% on a system-wide basis in drought years.

4.1.3 Scenario 3: Implementation of the Bay-Delta Plan Amendment Table 4 below provides projected supplies and demands under Scenario 3. The RWS is projected to experience significant shortfalls in single dry and multiple dry years through 2045, regardless of whether the proposed project is constructed. These significant shortfalls are a result of implementation of the Bay-Delta Plan Amendment and not attributed to the incremental retail demand associated with the proposed project. Shortfalls would range from about 11 to 29 mgd, corresponding to water use reduction in the retail service area ranging from 15-36%, over the next 20 years.

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Revised WSA for 3251 20th Avenue (Stonestown) Project
September 26, 2023

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Table 3: Projected Supply and Demand Comparison Under Scenario 1 (No Implementation of the Bay-Delta Plan Amendment or the Proposed Voluntary Agreement) (mgd)

Normal
Year
Single
Dry Year1
Multiple Dry Years2
Year 1 Year 2 Year 3 Year 4 Year 5
2025
Total Retail Demand3 71.3 71.3 71.3 71.3 71.3 71.3 71.3 Total Retail Supply4 71.3 71.3 71.3 71.3 71.3 71.3 71.3 Shortfall 0.0 0.0 0.0 0.0 0.0 0.0 0.0
Shortfall as % of Demand 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 2030
Total Retail Demand3 73.0 73.0 73.0 73.0 73.0 73.0 73.0 Total Retail Supply4 73.0 73.0 73.0 73.0 73.0 73.0 73.0 Shortfall 0.0 0.0 0.0 0.0 0.0 0.0 0.0
Shortfall as % of Demand 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 2035
Total Retail Demand3 75.0 75.0 75.0 75.0 75.0 75.0 75.0 Total Retail Supply4 75.0 75.0 75.0 75.0 75.0 75.0 75.0 Shortfall 0.0 0.0 0.0 0.0 0.0 0.0 0.0
Shortfall as % of Demand 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 2040
Total Retail Demand3 77.9 77.9 77.9 77.9 77.9 77.9 77.9 Total Retail Supply4 77.9 77.9 77.9 77.9 77.9 77.9 77.9 Shortfall 0.0 0.0 0.0 0.0 0.0 0.0 0.0
Shortfall as % of Demand 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 2045
Total Retail Demand3, 5 81.1 81.1 81.1 81.1 81.1 77.0 77.0 Total Retail Supply4 81.1 81.1 81.1 81.1 81.1 81.1 81.1 Shortfall 0.0 0.0 0.0 0.0 0.0 4.1 4.1
Shortfall as % of Demand 0.0% 0.0% 0.0% 0.0% 0.0% 5.3% 5.3% Notes:

1. During all single dry years, no RWS system-wide shortages are in effect.

2. During multiple dry years, no RWS system-wide shortages are in effect until years 4 and 5 at 2045 levels of demand. During those years, a 10% system-wide shortage is in effect.

3. Total retail demands correspond to those in Table 3 of the 2023 Interim Water Demand Projections.

4. Local supplies (i.e., supplies not from the RWS, including groundwater and recycled water) correspond to those in Table 6-5 of the UWMP. Local supplies are assumed to be used before RWS supplies to meet retail demand.

5. As amended in 2018, the WSAP Tier One Allocation Plan requires retail customers to conserve a minimum of 5% during droughts. If, during a declared water shortage, retail demands on the RWS are lower than the retail allocation in a dry year, retail demands on the RWS will be reduced by 5%. This provision is in effect in years 4 and 5 of a multi-dry year sequence at 2045 levels of demand.

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Revised WSA for 3251 20th Avenue (Stonestown) Project
September 26, 2023

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Table 4: Projected Supply and Demand Comparison Under Scenario 3 (Implementation of the Bay-Delta Plan Amendment) (mgd)

Normal
Year
Single
Dry
Year1
Multiple Dry Years2
Year 1 Year 2 Year 3 Year 4 Year 5
2025
Total Retail Demand3 71.3 71.3 71.3 71.3 71.3 71.3 71.3 Total Retail Supply4 70.7 59.5 59.5 51.5 51.5 51.5 51.5 Shortfall 0.0 -11.8 -11.8 -19.8 -19.8 -19.8 -19.8
Shortfall as % of Demand 0.0% -16.5% -16.5% -27.8% -27.8% -27.8% -27.8% 2030
Total Retail Demand3 73.0 73.0 73.0 73.0 73.0 73.0 73.0 Total Retail Supply4 72.4 61.4 61.4 53.4 53.4 53.4 53.4 Shortfall 0.0 -11.6 -11.6 -19.6 -19.6 -19.6 -19.6
Shortfall as % of Demand 0.0% -15.9% -15.9% -26.8% -26.8% -26.8% -26.8% 2035
Total Retail Demand3 75.0 75.0 75.0 75.0 75.0 75.0 75.0 Total Retail Supply4 74.5 63.8 63.8 55.5 55.5 55.5 51.4 Shortfall 0.0 -11.2 -11.2 -19.5 -19.5 -19.5 -23.6
Shortfall as % of Demand 0.0% -14.9% -14.9% -26.0% -26.0% -26.0% -31.5% 2040
Total Retail Demand3 77.9 77.9 77.9 77.9 77.9 77.9 77.9 Total Retail Supply4 77.4 66.4 66.4 57.9 57.9 52.0 52.0 Shortfall 0.0 -11.5 -11.5 -20.0 -20.0 -25.9 -25.9
Shortfall as % of Demand 0.0% -14.8% -14.8% -25.7% -25.7% -33.2% -33.2% 2045
Total Retail Demand3 81.1 81.1 81.1 81.1 81.1 81.1 81.1 Total Retail Supply4 80.6 60.1 60.1 60.1 60.1 52.1 52.1 Shortfall 0.0 -21.0 -21.0 -21.0 -21.0 -29.0 -29.0
Shortfall as % of Demand 0.0% -25.9% -25.9% -25.9% -25.9% -35.8% -35.8% Notes:

1. During a single dry year, system-wide shortages of 30 – 40% are in effect (see Table 8-3 of the 2020 UWMP). For this analysis, shortages greater than 20% are considered to have the same retail/wholesale allocation as the maximum Stage 4, 16-20% system-wide shortage in the Water Shortage Allocation Plan (WSAP).

2. During multiple dry years, system-wide shortages of 30 – 55% are in effect (see Table 8-3 of the 2020 UWMP). For this analysis, shortages greater than 20% are considered to have the same retail/wholesale allocation as the maximum Stage 4, 16-20% system-wide shortage in the WSAP.

3. Total retail demands correspond to those in Table 3 of the 2023 Interim Water Demand Projections.

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September 26, 2023

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4.2 Potential for Shortages in SFPUC Service Area
The inflow to SFPUC reservoirs can vary greatly from year to year, based on the hydrology of the region. When inflows are low during dry years, the potential exists for water supply shortages in the SFPUC service area. The occurrence of shortages depends on the magnitude and duration of dry conditions, and also on the system demand for water supply.

• In an evaluation of historical hydrology (1920 – 2017) combined with 2020 system demand, the potential for water supply shortages due to dry hydrology is low.
• When projected system demand in 2045 (an increase over 2020 demand) is evaluated along with historical hydrology, the potential for shortage increases but remains relatively low.
• W hen large increases in instream flow requirements (such as those associated with the Bay-Delta Plan update) are included in either of the above evaluations, the potential for water shortages in the SFPUC system increases markedly.

The instream flow requirements are analogous to an increase in demand in this evaluation.

4.3 Water Use Reduction Implications to the Proposed Project While the levels of water use reduction described above apply to the retail service area as a whole (i.e., 15-36% under Scenario 3), the SFPUC may allocate different levels of water use reduction to individual retail customers based on customer type (e.g., dedicated irrigation, single family residential, multi-family residential, commercial) to achieve the required level of retail system-wide demand reduction. Allocation methods and processes that have been considered in the past and may be used in future droughts are described in the SFPUC’s 2020 Water Shortage Contingency Plan (Appendix K of the UWMP). For both residential and commercial customers, the SFPUC may implement varying levels of water use reductions based on the baseline level of water use, e.g., require less reduction from customers that use less water to begin with. Under the 2020 Water Shortage Contingency Plan, the allocation method or combination of methods that would be applied during water shortages caused by drought would be subject to the discretion of the General Manager.

In accordance with the Water Shortage Contingency Plan, the level of water use reduction that would be imposed on the proposed project would be determined at the time of a drought or other water shortage and cannot be established with certainty prior to the shortage event. However, newly constructed buildings, such as the proposed project, have water-efficient fixtures and non-potable water systems that comply with the latest regulations and should be better prepared than older buildings to meet the required reductions.

4.4 Findings
Regarding the availability of water supplies to serve the proposed project beginning in 2027, the SFPUC finds, based on the entire record before it, as follows:

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September 26, 2023

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• During single dry years and multiple dry years under Scenario 2— Implementation of a Voluntary Agreement—the SFPUC would still face a shortfall in single dry and multiple dry years, thus requiring water use reduction, but to a lesser degree and in closer alignment to the LOS goal of no more than 20% system-wide water use reduction compared to that which would occur under Scenario 3. Because negotiations in furtherance of the November 9, 2022 Voluntary Agreement Memorandum of Understanding continue in earnest, and litigation challenging the adoption of the Bay-Delta Plan Amendment remains pending, SFPUC further finds that the supply and demand that would result under Scenario 2 are more likely to occur than those projected in Scenario 3.
• During single dry years and multiple dry years under Scenario 3— Implementation of the Bay-Delta Plan Amendment—the SFPUC cannot reliably meet the projected demands of its retail customers, including the proposed project, existing customers, and foreseeable future development, without water use reduction at a level greater than that required to achieve the LOS goal of a maximum of 20% system-wide average water use reduction. The SFPUC estimates it would impose up to 36% water use reductions across the retail service area.
• The SFPUC’s 2020 Water Shortage Contingency Plan describes allocation methods and processes that may be used in future droughts. For both residential and commercial customers, the SFPUC may implement varying levels of water use reductions based on the baseline level of water use, e.g., require less reduction from customers that use less water to begin with. For the proposed project specifically, these policies may result in lower levels of mandatory water use reduction as a result of the installation of water-efficient plumbing fixtures and non-potable water systems associated with new construction.
• Under Scenario 3, the relatively small volume of water demand generated by the proposed project itself would not exacerbate the projected shortfalls resulting from implementation of the Bay-Delta Plan Amendment. Regardless of whether the proposed project is constructed, with implementation of the Bay- Delta Plan Amendment, the SFPUC’s existing and planned water supplies will not meet the water demands of its retail service area in dry years without significant demand reductions.

Approval of this WSA by the Commission is not equivalent to approval of the development project for which the WSA is prepared. A WSA is an informational document required to be prepared for use in the City’s environmental review of a project under CEQA. It assesses the adequacy of water supplies to serve the proposed project and cumulative demand.

Furthermore, this WSA is not a “will serve” letter and does not verify the adequacy of existing distribution system capacity to serve the proposed project. A “will serve” letter and/or hydraulic analysis must be requested separately from the SFPUC City Distribution Division to verify hydraulic capacity.

While this WSA contains information provided by or on behalf of the project sponsor regarding the proposed project’s plans for onsite water reuse and demand estimates using the SFPUC’s Non-potable Water Calculator, any information submitted to the SFPUC for preparation of this WSA does not fulfill the requirements of the Non-potable Water Ordinance. City review and approval of a proposed onsite water system must be performed separately through the Non-potable Water Program.

If there are any questions or concerns, please contact Steve Ritchie at (415) 934- 5736 or [email protected].

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Revised WSA for 3251 20th Avenue (Stonestown) Project
September 26, 2023

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Attachments: Attachment A, 2023 Interim Water Demand Projections Attachment B, 3251 20th Avenue (Stonestown) Project Demand Memo

Attachment A –
2023 Interim Water Demand Projections

2023 Interim Water Demand
Projections
for the City and County of San Francisco

Prepared by:

San Francisco Public Utilities Commission

September 2023

San Francisco Public Utilities Commission

2023 Interim Water Demand Projections i
Table of Contents

1.0 Introduction ......................................................................................................................................... 1

1.1 Purpose of Water Supply Assessments ........................................................................................ 1

1.2 Purpose of this Document ............................................................................................................. 1

1.3 What this Document Does and Does Not Address ....................................................................... 1

2.0 Housing Unit Projections ................................................................................................................... 2

3.0 Retail Water Demands ........................................................................................................................ 2

4.0 Water Supply and Demand Comparisons ........................................................................................ 5

4.1 With Bay-Delta Plan Amendment .................................................................................................. 5

4.2 Without Bay-Delta Plan Amendment............................................................................................. 5

List of Tables
Table 1: Housing Unit Projections ................................................................................................................. 2 Table 2: Multi-Family Residential Water Demands (million gallons per day [mgd]) ..................................... 3 Table 3: Retail Water Demands (mgd) ......................................................................................................... 4 Table 4: Retail Supply and Demand Comparison for Projected Normal & Dry Year Scenarios With Bay- Delta Plan Amendment (mgd) ....................................................................................................................... 6 Table 5: Retail Supply and Demand Comparison for Projected Normal & Dry Year Scenarios Without Bay- Delta Plan Amendment (mgd) ....................................................................................................................... 8

List of Appendices
Appendix A: San Francisco Planning Memorandum
Appendix B: Woodard & Curran Memorandum

San Francisco Public Utilities Commission

2023 Interim Water Demand Projections 1

1.0 Introduction

1.1 Purpose of Water Supply Assessments
The California Water Code (Sections 10910 through 10915) requires urban water suppliers to evaluate water supply availability to inform environmental review for qualifying projects ("water demand projects") defined in Water Code Section 10912(a). Water Code Section 10910 requires the preparation of a "water supply assessment" (WSA) for water demand projects that include a determination of whether available water supplies are sufficient to serve the demand generated by the project, as well as reasonably foreseeable cumulative demand over a 20 year period, including years of normal precipitation, single dry, and multiple dry years. If the water supplies needed by a water demand project were accounted for in the water supplier's most recently adopted Urban Water Management Plan (UWMP), under Water Code Section 10910(c)(2), the water supplier may incorporate the requested information from the UWMP in preparing a WSA for a water demand project.

1.2 Purpose of this Document
The SFPUC most recently adopted the 2020 UWMP update for the City and County of San Francisco in June 2021. As described in the 2020 UWMP, Section 4.1.2, Projected Retail Demands, the 2020 UWMP relied on the San Francisco Planning Department's (SF Planning) housing projections based on the Housing Element 2022 Update, which was still under development when the 2020 UWMP was adopted.

One of the objectives of the Housing Element 2022 Update was to produce an average of 5,000 housing units per year with adjustments for certain large development plans. Since the SFPUC’s adoption of the 2020 UWMP in June 2021, the Planning Commission certified the Housing Element 2022 Update Environmental Impact Report (Housing Element EIR) in November 2022. The Housing Element EIR, which supported the City’s adoption of the Housing Element in January 2023, assumed slightly higher housing unit projections than those used in the 2020 UWMP, but was still in line with the objective to produce an average of 5,000 housing units per year. Nonetheless, as a result of the slightly higher housing unit projections associated with the Housing Element EIR, the SFPUC determined that its 2020 UWMP no longer accounted for all projected retail water demands.

The SFPUC will not be updating its UWMP until 2025. Therefore, during this interim period, the SFPUC has prepared the 2023 Interim Water Demand Projections herein to document the SFPUC’s projected retail water supplies when compared to projected retail water demands associated with the adopted Housing Element 2022 Update. This document also adjusts the retail water supply projections to meet the updated retail water demands.

The information in this document, in concert with the background information provided in the 2020 UWMP that are not superseded by the 2023 Interim Water Demand Projections herein, can be used in the development of WSAs for pending water demand projects.

1.3 What this Document Does and Does Not Address
This document only updates the following items from the 2020 UWMP as they are directly related to the change in housing unit projections:
• Retail water demand projections, specifically demands of the in-City multi-family residential sector, through 2045
• Retail water supply and demand comparisons (i.e., surpluses and shortfalls) during normal, single dry, and multiply dry years through 2045
San Francisco Public Utilities Commission

2023 Interim Water Demand Projections 2
This document does not update the following items from the 2020 UWMP as they are not directly related to the change in housing unit projections:
• Population projections associated with the Housing Element 2022 Update • Employment projections associated with the Housing Element 2022 Update • Retail water demands for the single family residential and non-residential sectors • Retail water loss
• Retail water savings associated with Conservation and Onsite Water Reuse programs • Suburban retail water demands
• Wholesale water demands
• Status of water supply projects

2.0 Housing Unit Projections
SF Planning provided updated housing unit projections in alignment with the Housing Element EIR in a memorandum to the SFPUC dated August 18, 2023 (Appendix A). Per SF Planning’s recommendation, it is assumed that the number of single-family detached houses will not increase from existing stock and that all future net housing growth will take the form of multi-family structures.

Table 1 compares the updated housing unit projections to those used in the 2020 UWMP in 5-year increments from 2025 to 2045. SFPUC used the updated housing unit projections as inputs to the same water demand forecasting model (i.e., econometric model) that was developed for the 2020 UWMP, described in the next section.

Table 1: Housing Unit Projections
2025 2030 2035 2040 2045
Used in 2020 UWMP 425,118 450,923 476,728 502,533 528,338 2023 Update 432,667 458,333 483,600 509,000 534,000
Net Change 7,549 7,410 6,872 6,467 5,662

3.0 Retail Water Demands
As described in the 2020 UWMP, Section 3.2, Retail Service Area, retail customers include the residents, businesses, and industries located within City limits, referred to as the in-City retail service area. Retail service is also provided to a patchwork of customers located outside the City, such as the Town of Sunol, San Francisco International Airport, Lawrence Livermore National Laboratory, and Castlewood County Service Area. These areas are not contiguous and are collectively referred to as the suburban retail service area.

The SFPUC uses econometric models to project the demands for its in-City single family residential, multi-family residential, and commercial/industrial sectors. Other in-City non-residential demands (i.e., irrigation and municipal) and suburban retail demands are estimated based on historical consumption and supplement the demands projected by the econometric models. Water loss is forecasted separately. For San Francisco Public Utilities Commission

2023 Interim Water Demand Projections 3
more information about how retail water demand projections were developed for the 2020 UWMP, refer to Section 4.1.2, Projected Retail Demands, of the 2020 UWMP.

The SFPUC, with the support of its consultant team that developed the econometric models used for the 2020 UWMP, re-ran the model specific to the multi-family residential sector using the updated housing unit projections described in the previous section. No other model inputs were changed from those that were used for the 2020 UWMP. The resulting model outputs are detailed in Appendix B and summarized in Table 2 below. Multi-family residential demands increased by about 0.5 to 0.6 mgd, or 1.5 to 2.5%, compared to those in the 2020 UWMP.

Table 2: Multi-Family Residential Water Demands (million gallons per day [mgd]) 2025 2030 2035 2040 2045
Used in 2020 UWMP 23.7 25.6 27.9 30.3 33.0
2023 Update 24.3 26.2 28.4 30.9 33.5
Difference 0.6 0.6 0.6 0.5 0.5
% Difference from 2020 UWMP 2.5% 2.3% 2.0% 1.8% 1.5%

Total retail water demand projections are shown in Table 3, which supersedes Table 4-1 of the 2020 UWMP. These projections comprise the updated multi-family residential demands from Table 2 and the unchanged demands for the remaining sectors. The demands of the remaining sectors are not updated as they are not directly related to the change in housing unit projections. Total retail demands increased by about 0.6 to 0.8% compared to those in the 2020 UWMP.

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2023 Interim Water Demand Projections 4
Table 3: Retail Water Demands (mgd)
Retail Sector or Use Type
Actuala Projectedb
2020 2025 2030 2035 2040 2045
In-City Retail
Single-Family Residential 14.5 13.7 13.5 13.4 13.5 13.5 Multi-Family Residential 22.9 24.3 26.2 28.4 30.9 33.5
Non-residential 20.9 22.9 22.9 22.8 23.1 23.6
Water Lossc 7.2 6.0 6.0 6.0 6.0 6.0
Subtotal In-City Retail Demand 65.3 66.9 68.6 70.6 73.5 76.7 Suburban Retail
Single-Family Residentiald 0.1 0.1 0.1 0.1 0.1 0.1
Non-Residential 3.1 4.0 4.0 4.0 4.0 4.0
Groveland CSDe 0.3 0.3 0.3 0.3 0.3 0.3
Water Lossc 0.0 0.0 0.0 0.0 0.0 0.0
Subtotal Suburban Retail Demand 3.5 4.4 4.4 4.4 4.4 4.4 Total Retail Demand 68.8 71.3 73.0 75.0 77.9 81.1
% Difference from 2020 UWMP N/A 0.8% 0.8% 0.8% 0.7% 0.6% a Actual consumption data are obtained from customer billing data. b Single family residential and multi-family residential demand projections are from an econometric model developed for the SFPUC. Non-residential demands include commercial/industrial demands, which are also from an econometric model, as well as municipal and irrigation demands, which are assumed to remain constant at the previous five-year average level.
c Water losses include both apparent and real losses. Suburban retail water losses are considered to be negligible. Actual water loss in 2020 is based on SFPUC’s July 2019 – June 2020 water loss audit. d Suburban retail residential demands are for single family only as no multi-family residential buildings are served.
e Groveland Community Services District (CSD) is accounted for as a retail customer for the purpose of this table and subsequent retail supply and demand comparisons in the 2020 UWMP. Demand projections were provided by Groveland CSD based on its population projections and assumed per capita water use of 107 GPCD (projections are subject to change as part of its UWMP process). In the corresponding standardized tables in UWMP 2020 Appendix B, Groveland CSD is not reported as retail, but rather wholesale.

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2023 Interim Water Demand Projections 5

4.0 Water Supply and Demand Comparisons
This section compares the SFPUC’s retail water supplies (unchanged from the 2020 UWMP) and demands (updated in Table 3) through 2045 during normal, single dry, and multiple dry years. The supply and demand comparisons are presented for two Regional Water System (RWS) supply scenarios: (1) with full implementation of the Bay-Delta Plan Amendment and (2) without implementation of the Bay- Delta Plan Amendment. For more information about these scenarios and how their corresponding supplies were estimated, refer to Section 8, Water Supply Reliability Assessment, of the 2020 UWMP1.

4.1 With Bay-Delta Plan Amendment
The instream flow requirements of the Bay-Delta Plan Amendment would impact the RWS supplies in single dry years and multiple dry years. The comparison of retail demands and supplies under the Bay- Delta Plan Amendment is presented in Table 4, which supersedes Table 8-4 of the 2020 UWMP and demonstrates the following:
• Normal Years: During normal hydrologic years, the SFPUC will have adequate supplies to meet its projected retail water demands. This is unchanged from the 2020 UWMP. • Single Dry Year: During single dry years, there would be an anticipated 30 to 40% shortage of RWS supplies. When the supplies available to retail customers (RWS plus local supplies) are compared to the projected retail demands, a retail supply shortfall of 15% to 26% (11 to 21 mgd) is expected in single dry year conditions. These shortfalls are less than 1%, or 1 mgd, higher than estimated in the 2020 UWMP.
• Multiple Dry Years: If a multiple dry year event occurs, there would be anticipated shortages in RWS supplies of 30 to 49%, depending on demand levels. When the supplies available to retail customers (RWS plus local supplies) are compared to the projected retail demands, there is an anticipated shortfall of almost 36%, or 29 mgd, by the fifth dry year at 2045 projected levels of demand. This shortfall is less than 1%, or 1 mgd, higher than estimated in the 2020 UWMP.

4.2 Without Bay-Delta Plan Amendment
Without implementation of the Bay-Delta Plan Amendment, existing and planned supplies would meet all projected RWS demands in all years except deep into a multi-year drought at 2045 projected levels of demand. The comparison of retail demands and supplies is presented in Table 5, which supersedes Table 8-6 of the 2020 UWMP and demonstrates the following:
• Normal Years: During normal hydrologic years, the SFPUC will have adequate supplies to meet its projected retail water demands. This is unchanged from the 2020 UWMP. • Single Dry Year: During single dry years, there are no anticipated shortages of RWS supplies.

This is unchanged from the 2020 UWMP.
• Multiple Dry Years: In the multiple dry year scenario, the SFPUC would only experience system- wide shortages in RWS supplies of 10% during years 4 and 5 of an extended drought at 2045

1 Section 7.3.1, page 7-5, of the 2020 UWMP states, “Although the [State Water Resources Control Board] has stated it intends to implement the Bay-Delta Plan Amendment on the Tuolumne River by the year 2022, given the current level of uncertainty, it is assumed for the purposes of this draft UWMP that the Bay-Delta Plan Amendment will be fully implemented starting in 2023.” To date, the Bay-Delta Plan Amendment has not been implemented and the SFPUC currently does not have an anticipated date for implementation.

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2023 Interim Water Demand Projections 6
levels of demand. In a 10% shortage, retail customers would reduce their demands by 5% as required by the Water Supply Agreement between SFPUC and its Wholesale Customers. As a result of this demand reduction, there is a projected surplus of 5.3%, or 4.1 mgd, which is 0.1 mgd greater than that estimated in the 2020 UWMP.

Table 4: Retail Supply and Demand Comparison for Projected Normal & Dry Year Scenarios With Bay-Delta Plan Amendment (mgd)

Normal
Year
Single
Dry
Yeara
Multiple Dry Yearsb
Year 1 Year 2 Year 3 Year 4 Year 5
2025
Total Retail Demand 71.3 71.3 71.3 71.3 71.3 71.3 71.3
Baseline Retail Demandc 71.3 71.3 71.3 71.3 71.3 71.3 71.3 5% Retail Demand Reductiond N/A N/A N/A N/A N/A N/A N/A Total Retail Supply 70.7 59.5 59.5 51.5 51.5 51.5 51.5
Retail Groundwatere 1.4 1.4 1.4 1.4 1.4 1.4 1.4
Retail Recycled Waterf 2.1 2.1 2.1 2.1 2.1 2.1 2.1
RWS Supply Utilized by Retailg 67.2 56.0 56.0 48.0 48.0 48.0 48.0 Difference (Supply Surplus or Shortfall) 0.0 -11.8 -11.8 -19.8 -19.8 -19.8 -19.8 Difference as Percentage of Demand 0.0% -16.5% -16.5% -27.8% -27.8% -27.8% -27.8% 2030
Total Retail Demand 73.0 73.0 73.0 73.0 73.0 73.0 73.0
Baseline Retail Demandc 73.0 73.0 73.0 73.0 73.0 73.0 73.0 5% Retail Demand Reductiond N/A N/A N/A N/A N/A N/A N/A Total Retail Supply 72.4 61.4 61.4 53.4 53.4 53.4 53.4
Retail Groundwatere 2.4 2.4 2.4 2.4 2.4 2.4 2.4
Retail Recycled Waterf 2.5 2.5 2.5 2.5 2.5 2.5 2.5
RWS Supply Utilized by Retailg 67.5 56.5 56.5 48.5 48.5 48.5 48.5 Difference (Supply Surplus or Shortfall) 0.0 -11.6 -11.6 -19.6 -19.6 -19.6 -19.6 Difference as Percentage of Demand 0.0% -15.9% -15.9% -26.8% -26.8% -26.8% -26.8% 2035
Total Retail Demand 75.0 75.0 75.0 75.0 75.0 75.0 75.0
Baseline Retail Demandc 75.0 75.0 75.0 75.0 75.0 75.0 75.0 5% Retail Demand Reductiond N/A N/A N/A N/A N/A N/A N/A Total Retail Supply 74.5 63.8 63.8 55.5 55.5 55.5 51.4
Retail Groundwatere 3.4 3.4 3.4 3.4 3.4 3.4 3.4
Retail Recycled Waterf 2.5 2.5 2.5 2.5 2.5 2.5 2.5
RWS Supply Utilized by Retailg 68.6 57.9 57.9 49.6 49.6 49.6 45.5 Difference (Supply Surplus or Shortfall) 0.0 -11.2 -11.2 -19.5 -19.5 -19.5 -23.6 Difference as Percentage of Demand 0.0% -14.9% -14.9% -26.0% -26.0% -26.0% -31.5%

San Francisco Public Utilities Commission

2023 Interim Water Demand Projections 7

Normal
Year
Single
Dry
Yeara
Multiple Dry Yearsb
Year 1 Year 2 Year 3 Year 4 Year 5
2040
Total Retail Demand 77.9 77.9 77.9 77.9 77.9 77.9 77.9
Baseline Retail Demandc 77.9 77.9 77.9 77.9 77.9 77.9 77.9 5% Retail Demand Reductiond N/A N/A N/A N/A N/A N/A N/A Total Retail Supply 77.4 66.4 66.4 57.9 57.9 52.0 52.0
Retail Groundwatere 4.4 4.4 4.4 4.4 4.4 4.4 4.4
Retail Recycled Waterf 2.5 2.5 2.5 2.5 2.5 2.5 2.5
RWS Supply Utilized by Retailg 70.5 59.5 59.5 51.0 51.0 45.1 45.1 Difference (Supply Surplus or Shortfall) 0.0 -11.5 -11.5 -20.0 -20.0 -25.9 -25.9 Difference as Percentage of Demand 0.0% -14.8% -14.8% -25.7% -25.7% -33.2% -33.2% 2045
Total Retail Demand 81.1 81.1 81.1 81.1 81.1 81.1 81.1
Baseline Retail Demandc 81.1 81.1 81.1 81.1 81.1 81.1 81.1 5% Retail Demand Reductiond N/A N/A N/A N/A N/A N/A N/A Total Retail Supply 80.6 60.1 60.1 60.1 60.1 52.1 52.1
Retail Groundwatere 4.4 4.4 4.4 4.4 4.4 4.4 4.4
Retail Recycled Waterf 2.5 2.5 2.5 2.5 2.5 2.5 2.5
RWS Supply Utilized by Retailg 73.7 53.2 53.2 53.2 53.2 45.2 45.2 Difference (Supply Surplus or Shortfall) 0.0 -21.0 -21.0 -21.0 -21.0 -29.0 -29.0 Difference as Percentage of Demand 0.0% -25.9% -25.9% -25.9% -25.9% -35.8% -35.8% Normal, single dry, and multiple dry year conditions are on a water year basis. a During a single dry year, system-wide shortages of 30 – 40% are in effect (see Table 8-3 of the 2020 UWMP). For this analysis, shortages greater than 20% are considered to have the same retail/wholesale allocation as the maximum Stage 4, 16-20% system-wide shortage in the Water Shortage Allocation Plan (WSAP). b During multiple dry years, system-wide shortages of 30 – 55% are in effect (see Table 8-3 of the 2020 UWMP). For this analysis, shortages greater than 20% are considered to have the same retail/wholesale allocation as the maximum Stage 4, 16-20% system-wide shortage in the WSAP.
c Total retail demands correspond to those in Table 3 and reflect passive and active conservation, onsite water reuse savings, and water loss. Demands for Groveland Community Services District is included in the table above. d As amended in 2018, the WSAP Tier One Allocation Plan requires retail customers to conserve a minimum of 5% during droughts. If, during a declared water shortage, retail demands on the Regional Water System (RWS) are lower than the retail allocation in a dry year, retail demands on the RWS will be reduced by 5%. An N/A on this row means that either this 5% rationing requirement doesn't apply (i.e. no declared water shortage), or retail customers are already rationing greater than 5%.
e Groundwater supplies are assumed to be equivalent to projected demands for the San Francisco Groundwater Supply Project (ramping up to 4 mgd by 2040) and Castlewood County Service Area (0.4 mgd). Groundwater availability would not be affected by dry year conditions.
f Recycled water supplies are assumed to be equivalent to projected demands related to the Westside Recycled Water Project (1.6 mgd by 2021 and 1.8 mgd by 2030), Harding Park and Fleming Golf Courses (0.23 mgd), and Sharp Park Golf Course (up to 0.1 mgd) and Treasure Island (0.2 mgd by 2025 and 0.4 mgd by 2030). Recycled water availability would not be affected by dry year conditions.
g Procedures for RWS allocations and the WSAP are described in Section 8.3 of the 2020 UWMP. Groundwater and recycled water are assumed to be used before RWS supplies to meet retail demand. However, in normal years, if groundwater and recycled water supplies are not available, up to 81 mgd of RWS supply could be used.

San Francisco Public Utilities Commission

2023 Interim Water Demand Projections 8

Table 5: Retail Supply and Demand Comparison for Projected Normal & Dry Year Scenarios Without Bay-Delta Plan Amendment (mgd)

Normal
Year
Single
Dry
Yeara
Multiple Dry Yearsb
Year 1 Year 2 Year 3 Year 4 Year 5
2025
Total Retail Demand 71.3 71.3 71.3 71.3 71.3 71.3 71.3
Baseline Retail Demandc 71.3 71.3 71.3 71.3 71.3 71.3 71.3 5% Retail Demand Reductiond N/A N/A N/A N/A N/A N/A N/A Total Retail Supply 71.3 71.3 71.3 71.3 71.3 71.3 71.3
Retail Groundwatere 1.4 1.4 1.4 1.4 1.4 1.4 1.4
Retail Recycled Waterf 2.1 2.1 2.1 2.1 2.1 2.1 2.1
RWS Supply Utilized by Retailg 67.8 67.8 67.8 67.8 67.8 67.8 67.8 Difference (Supply Surplus or Shortfall) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Difference as Percentage of Demand 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 2030
Total Retail Demand 73.0 73.0 73.0 73.0 73.0 73.0 73.0
Baseline Retail Demandc 73.0 73.0 73.0 73.0 73.0 73.0 73.0 5% Retail Demand Reductiond N/A N/A N/A N/A N/A N/A N/A Total Retail Supply 73.0 73.0 73.0 73.0 73.0 73.0 73.0
Retail Groundwatere 2.4 2.4 2.4 2.4 2.4 2.4 2.4
Retail Recycled Waterf 2.5 2.5 2.5 2.5 2.5 2.5 2.5
RWS Supply Utilized by Retailg 68.1 68.1 68.1 68.1 68.1 68.1 68.1 Difference (Supply Surplus or Shortfall) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Difference as Percentage of Demand 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 2035
Total Retail Demand 75.0 75.0 75.0 75.0 75.0 75.0 75.0
Baseline Retail Demandc 75.0 75.0 75.0 75.0 75.0 75.0 75.0 5% Retail Demand Reductiond N/A N/A N/A N/A N/A N/A N/A Total Retail Supply 75.0 75.0 75.0 75.0 75.0 75.0 75.0
Retail Groundwatere 3.4 3.4 3.4 3.4 3.4 3.4 3.4
Retail Recycled Waterf 2.5 2.5 2.5 2.5 2.5 2.5 2.5
RWS Supply Utilized by Retailg 69.1 69.1 69.1 69.1 69.1 69.1 69.1 Difference (Supply Surplus or Shortfall) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Difference as Percentage of Demand 0.0% 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

San Francisco Public Utilities Commission

2023 Interim Water Demand Projections 9

During those years, a 10% system-wide shortage is in effect. c Total retail demands correspond to those in Table 3 and reflect passive and active conservation, onsite water reuse savings, and water loss. Demands for Groveland Community Services District is included in the table above. d As amended in 2018, the Water Shortage Allocation Plan (WSAP) Tier One Allocation Plan requires retail customers to conserve a minimum of 5% during droughts. If, during a declared water shortage, retail demands on the Regional Water System (RWS) are lower than the retail allocation in a dry year, retail demands on the RWS will be reduced by 5%. An N/A on this row means that either this 5% rationing requirement doesn't apply (i.e. no declared water shortage), or retail customers are already rationing greater than 5%.
e Groundwater supplies are assumed to be equivalent to projected demands for the San Francisco Groundwater Supply Project (ramping up to 4 mgd by 2040) and Castlewood County Service Area (0.4 mgd). Groundwater availability would not be affected by dry year conditions.
f Recycled water supplies are assumed to be equivalent to projected demands related to the Westside Recycled Water Project (1.6 mgd by 2021 and 1.8 mgd by 2030), Harding Park and Fleming Golf Courses (0.23 mgd), and Sharp Park Golf Course (up to 0.1 mgd) and Treasure Island (0.2 mgd by 2025 and 0.4 mgd by 2030). Recycled water availability would not be affected by dry year conditions.
g Procedures for RWS allocations and the WSAP are described in Section 8.3 of the 2020 UWMP. Groundwater and recycled water are assumed to be used before RWS supplies to meet retail demand. However, in normal years, if groundwater and recycled water supplies are not available, up to 81 mgd of RWS supply could be used.

San Francisco Public Utilities Commission
2023 Interim Water Demand Projections
Appendix A – San Francisco Planning Memorandum

August 18, 2023

Paula Kehoe
Director of Water Resources, SFPUC
525 Golden Gate Street, 10th Floor
San Francisco, CA 94102

Re: Projections of growth for San Francisco through 2050

Dear Paula:

On October 27, 2020, the Planning Department provided SFPUC household and job growth projections to inform the citywide water demand projections in the 2020 update of the SFPUC’s Urban Water Management Plan (UWMP). The SFPUC adopted the 2020 UWMP in June 2021. Since that time, the Planning Commission certified the Housing Element 2022 Update Environmental Impact Report (Housing Element EIR or EIR) in November 2022. The EIR, which supported the City’s adoption of the Housing Element in January 2023, assumed slightly higher household projections than those used in the UWMP . As you requested, this memo provides the EIR’s household projections1 to inform a minor update to SFPUC’s water demand projections.

Citywide Growth Projections

Table 1 shows the Planning Department’s housing projections for the years 2020-2050. We recognize that the 2020 UWMP water planning horizon extends only to 2045.

Table 1: Development Projections
2020 2025 2030 2035 2040 2045 2050
Housing Units 407,000 432,667 458,333 483,600 509,000 534,000 559,000

The Housing Element update is required to be adopted every eight years by state law and was approved by the Board of Supervisors in January 2023 and certified by the state Department of Housing and Community Development on February 1, 2023. One of the primary goals of the Housing Element 2022 Update is to improve housing affordability by increasing the rate of housing production compared with the past several decades. The projections are based on the Housing Element objective of producing an average of approximately 5,000

1 The Housing Element EIR assumed slightly less job growth than that assumed in the Planning Department’s October 27, 2020 memo used to inform the 2020 UWMP water demand projections (i.e., EIR assumed 869,000 jobs in 2045 whereas October 2020 memo assumed 894,255 jobs). Given that the 2020 UWMP water demand projections used more conservative (i.e., slightly higher) job growth assumptions, there is no need to update the water demand projections to account for the Housing Element EIR job growth assumptions.

2 housing units per year, with adjustments for certain large development plans. These projections were analyzed in the Housing Element EIR. (The projections can be found in Appendix C of the EIR.) The Housing Element EIR considered two projection years – 2035 and 2050. For the purposes of generating the 5-year incremental projections required by the SFPUC through 2045, the Planning Department assumes a constant, straight-line average pace of housing production for the periods of 2020-2035 and 2035-2050.

Regarding the typology of projected new housing stock, our memo provided to SFPUC dated October 27, 2020, to inform preparation of the 2020 UWMP , contained analysis supporting a Planning Department recommendation that the SFPUC assume for the purposes of modelling citywide projected housing development in San Francisco that the number of single-family detached houses will not increase from existing stock and that all future net housing growth will take the form of multi-family structures. This recommendation is unchanged.

Sincerely,

Joshua Switzky
Acting Director of Citywide Planning

cc:

Fan Lau, SFPUC
Lisa Gibson, Planning
Wade Wietgrefe, Planning
Debra Dwyer, Planning
Julie Moore, Planning
Scott Edmondson, Planning
Peter Miljanich, City Attorney
Andrea Ruiz-Esquide, City Attorney

San Francisco Public Utilities Commission

2023 Interim Water Demand Projections

Appendix B – Woodard & Curran Memorandum

SFPUC 1 Woodard & Curran, Inc.

SFPUC Demand Forecast Model Re-Run with Updated Housing Unit Forecast August 25, 2023

TECHNICAL MEMORANDUM
TO: Paula Kehoe, Director of Water Resources, San Francisco Public Utilities Commission Fan Lau, Water Resources Division, San Francisco Public Utilities Commission PREPARED BY: Chris Hewes, Woodard & Curran
REVIEWED BY: Katie Cole, Woodard & Curran
DATE: August 25, 2023
RE: SFPUC Demand Forecast Model Re-Run with Updated Housing Unit Forecast

In 2020, the San Francisco Public Utilities Commission ( SFPUC) engaged The Brattle Group to develop an econometric-based water demand forecast model (Model) to generate retail water demands for the SFPUC’s 2020 Urban Water Management Plan (UWMP). A key input to the Model was household development forecasts provided b y the San Francisco Planning Department (October 27, 2020 memo from Joshua Switzky, Land Use & Community Planning Program Manager) . At the time, these forecasts were in draft form, developed during preparation of the city’s General Plan Housing Element (Ho using Element 2022 Update). Since June 2021 when the 2020 UWMP was published, the Planning Commission certified the Housing Element 2022 Update Environmental Impact Report (EIR) in November 2022. The EIR, which supported the City’s adoption of the Housing Element in January 2023, assumed slightly higher household forecasts than those used in the UWMP.

Woodard & Curran worked with the Model developers to re-run it with the updated housing development forecasts provided by the San Francisco Planning Department (see Section 1 – Updated Model Inputs). The resulting Model outputs (water demands) were combined with other values external to the Model that together provide full retail water demand for SFPUC (see Section 2 – Updated Results).

1. UPDATED MODEL INPUTS
See Table 1 for the updated housing development forecast provided by the San Francisco Planning Department ( August 18, 2023 memo from Joshua Switzky, Acting Director of Citywide Planning ). Per SFPUC's guidance in the previous Model effort, and re-confirmed by the San Francisco Planning Department for the current Model effort, it was assumed that there will not be an increase in the number of single-family detached houses from the existing stock. Therefore, the water demand forecast for the single-family sector is the same as the prior outputs. All future housing growth is expected to occur in the multi-family residential sector. No other inputs to the Model were changed (e.g., employment forecast, econometric variables, etc.).

Table 1: Housing Development Forecast
Housing Units 2020 2025 2030 2035 2040 2045
For 2020 UWMP 399,313 425,118 450,923 476,728 502,533 528,338 For 2023 Update 407,000 432,667 458,333 483,600 509,000 534,000

SFPUC 2 Woodard & Curran, Inc.

SFPUC Demand Forecast Model Re-Run with Updated Housing Unit Forecast August 25, 2023

2. UPDATED RESULTS
See Table 2 for the updated outputs directly from the Model. Table 3 shows the updated multi -family residential sector forecast details. Tables 2 and 3 contain rows that specify the water savings associated with the Onsite Water Reuse Program. These savings were esti mated for the 2020 UWMP but are not updated for this memo as (1) they are estimated separately from the Model and (2) the types of new multi -family residential projects and their participation in the Onsite Water Reuse Program are currently unknown.

See Table 4 for a comparison of the previous and updated multi-family residential sector forecasts.

See Table 5 for the updated retail demand forecast, which incorporates additional information that is external to the Model, as it was presented in the 2020 UWMP (e.g., municipal and irrigation demands in the “non-residential” sector, as well as Suburban Retail demands).

SFPUC 3 Woodard & Curran, Inc.

SFPUC Demand Forecast Model Re-Run with Updated Housing Unit Forecast August 25, 2023 Table 2: Model Outputs (mgd)

Notes:

FY2019-20: This column is a forecast that assumes no COVID -19 pandemic and average weather conditions. Actual demand for FY2019-20 is shown in Table 5 of this memo.

Unadjusted Baseline Demand: This is the raw output of the statistical forecast model.

Conservation Adjustments: These estimates are the output of the SFPUC Conservation model and have not been updated in this memo.

Multifamily Residential Fire Accounts: These values were supplied by SFPUC and have not been updated in this memo.

Commercial and Industrial: These forecasts are unchanged from the previous forecasts.

Grand Total: This row does not include water losses, suburban accounts, irrigation accounts , or municipal accounts.

The volumes from these additional sector types are included in Table 5 of this memo and are unchanged from the previous forecasts.

SFPUC 4 Woodard & Curran, Inc.

SFPUC Demand Forecast Model Re-Run with Updated Housing Unit Forecast August 25, 2023 Table 3: Multi-Family Demand Forecast Details

Notes:

FY2019-20: This column is a forecast that assumes no COVID -19 pandemic and average weather conditions. Actual demand for FY2019-20 is shown in Table 5 of this memo.

Unadjusted Baseline Demand: This is the raw output of the statistical forecast model.

Conservation Adjustments: These estimates are the output of the SFPUC Conservation model and have not been updated in this memo.

Table 4: Multi-Family Residential Water Demand Forecast (mgd) Multi-Family Residential Actuala Projectedb
2020 2025 2030 2035 2040 2045
From 2020 UWMP 22.9 23.7 25.6 27.9 30.3 33.0
From 2023 Update (from Table 3) 22.9 24.3 26.2 28.4 30.9 33.5 Difference 0.0 0.6 0.6 0.6 0.5 0.5
a Actual consumption data are obtained from customer billing data. b Multi-family residential demand projections are from an econometric model developed for the SFPUC.

SFPUC 5 Woodard & Curran, Inc.

SFPUC Demand Forecast Model Re-Run with Updated Housing Unit Forecast August 25, 2023 Table 5: Retail Water Demand Forecast (mgd)
Retail Sector or Use Type Actuala Projectedb
2020 2025 2030 2035 2040 2045
In-City Retail
Single-Family Residential 14.5 13.7 13.5 13.4 13.5 13.5 Multi-Family Residential 22.9 24.3 26.2 28.4 30.9 33.5
Non-residential 20.9 22.9 22.9 22.8 23.1 23.6
Water Lossc 7.2 6.0 6.0 6.0 6.0 6.0
Subtotal In-City Retail Demand 65.3 66.9 68.6 70.6 73.5 76.7 Suburban Retail
Single-Family Residentiald 0.1 0.1 0.1 0.1 0.1 0.1
Non-Residential 3.1 4.0 4.0 4.0 4.0 4.0
Groveland CSDe 0.3 0.3 0.3 0.3 0.3 0.3
Water Lossc 0.0 0.0 0.0 0.0 0.0 0.0
Subtotal Suburban Retail Demand 3.5 4.4 4.4 4.4 4.4 4.4 Total Retail Demand 68.8 71.3 73.0 75.0 77.9 81.1
a Actual consumption data are obtained from customer billing data. b Single family residential and multi-family residential demand projections are from an econometric model developed for the SFPUC. Non-residential demands include commercial/industrial demands, which are also from an econometric model, as well as municipal and irrigation demands, which are assumed to remain constant at the previous five -year average level.
c Water losses include both apparent and real losses. Suburban retail water losses ar e considered to be negligible.

Actual water loss in 2020 is based on SFPUC’s July 2019 – June 2020 water loss audit. d Suburban retail residential demands are for single family only as no multi-family residential buildings are served. e Groveland Community Services District (CSD) is accounted for as a retail customer for the purpose of this table and subsequent retail supply and demand comparisons in the 2020 UWMP. Demand projections were provided by Groveland CSD based on its population projections and assumed per capita water use of 107 GPCD (projections are subject to change as part of its UWMP process). In the corresponding standardized tables in UWMP 2020 Appendix B, Groveland CSD is not reported as retail, but rather wholesale.

Attachment B –
3251 20th Avenue (Stonestown) Project Demand Memo

September 18, 2023

To: Fan Lau, P.E. – San Francisco Utilities Commission
From: Florentina Craciun, AICP – Environmental Planning

Re: 3251 20th Avenues (Stonestown) Water Supply Assessment Request Planning Department File No. 2021-012028ENV

The purpose of this memorandum is to request that the San Francisco Public Utilities Commission (SFPUC) prepare a revised Water Supply Assessment (WSA) for the proposed project at 3251 20th Avenue (Stonestown), in compliance with CEQA Guidelines Section 15155 and Sections 10910 through 10915 of the California Water Code. A prior Project Water Demand Memo and WSA analysis was prepared for the project and was reviewed and approved by the SFPUC Commission on October 24, 2022. This Project Water Demand Memo request provides updated information based on current requirements for a modified project at 3251 20th Avenue (Stonestown Mall).

The project sponsor (Brookfield Properties Development) proposes to redevelop the approximately 27 acres of surface parking surrounding the existing Stonestown Galleria shopping mall into a master-planned, multi-phased, mixed-use residential and retail community. Under the Revised Variant, the existing 775,000-square-foot mall would remain, with changes to the façade, entrances, and exits. Overall, the proposed project would include up to approximately 3,491 residential units; up to 160,000 square feet of new retail sales and service use space; up to 96,000 square feet of non-retail sales and service use; approximately 63,000 square feet of institutional uses; approximately 4,700 parking spaces; 6 acres of open space; and infrastructure improvements.

The project sponsor provided project information intended to meet the requirements outlined in the SFPUC guidance memo dated January 13, 2022. A summary of the project description, average daily water demands, and supporting tables prepared by the project sponsor’s consultant (based on the SFPUC District Scale Non-Potable Water Calculator Version 9.1), are attached.

Should you have questions or need additional information from the Planning Department or the project sponsor, please contact me at 628.652.7510 or [email protected].

Sincerely,

Florentina Craciun, AICP

575 Market Street
Suite 3700
San Francisco, CA 94105
415.896.5900 phone
415.896.0332 fax

esassoc.com

memorandum
date July 28, 2023
to Florentina Craciun, San Francisco Planning Department, Environmental Planning

from Susan Yogi and Jill Feyk-Miney, ESA
subject Revised Stonestown Development Project Demand Memorandum for Preparation of Water Supply Assessment Case No. 2021-012028ENV

This memorandum presents the revised project description and project information regarding water demand in order for the San Francisco Public Utilities Commission (SFPUC) to prepare a Water Supply Assessment (WSA) for the Stonestown Development Project (proposed project). The SFPUC prepared the WSA for the proposed project based on the 2020 Urban Water Management Plan for the City and County of San Francisco. As described on page 2 of this memorandum, the original proposed project included a variant (original variant), which considered additional development. The previous WSA calculator was prepared using the original variant’s projected demand because it represents the most conservative buildout for the project site from a water demand perspective. The SFPUC approved the WSA for the proposed project by Resolution No. 22-0186 on October 24, 2022. Since then, the project sponsor has revised the original variant to add residential units and reduce non-retail sales and service and hotel uses (herein referred to as the “revised variant”). The “proposed project” as described in this memorandum refers to the original and revised variant. This memorandum is expected to be attached to the revised WSA as an appendix and referenced in the WSA as needed. Table 1 provides the basic information of the proposed project.

Revised Variant Description
The proposed Stonestown Development project is located on an approximately 41-acre site in the Lakeshore area in southwest San Francisco. The project sponsor (Brookfield Properties Development) proposes to redevelop the approximately 27 acres surrounding the existing on-site Stonestown Galleria shopping mall into a master- planned, multi-phased, mixed-use residential and retail community. Under the proposed project, the existing 760,000-square-foot Stonestown Galleria shopping mall would remain, with changes to the façade, entrances, and exits. The existing parking garage in the southwest corner of the project site, the vacant theater at the northwest corner of the site, and the CitySports and commercial building at the northeast corner of the site would be demolished and redeveloped as part of the proposed project.

Revised Stonestown Development Project Demand Memorandum for Preparation of Water Supply Assessment Case No. 2021-012028ENV 2 TABLE 1

PROJECT INFORMATION
Project Name Stonestown Development Project
Case No. 2021-012028ENV
Estimated Construction Completion 2032
Project Contact Florentina Craciun – 628.652.7510, [email protected] Current Land Use(s) Retail Sales and Services (shopping mall) Parking Lots
Institutional
Proposed Land Use(s) Residential
Retail Sales and Services
Non-Retail Sales and Services
Parking Lots
Hotel (the revised variant does not include hotel uses) Institutional
Project Address 3251 20th Avenue
Block/Lot 7295/Lots 2, 4, 6, 7, 35, 37, 38; 7296/Lots 5, 6, 7, 8, 9, 10 Project Site Size 1,781,604 square feet (40.9 acres)
Days In Operation Per Year 365 residential days; 365 retail days; 260 general office days, 260 childcare days

Overall, the proposed project would include up to approximately 2,930 residential units; up to 160,000 square feet of new retail sales and service use space; up to 200,000 square feet of new non-retail sales and service use1; up to approximately 100,000 square feet of hotel use; approximately 53,000 square feet of institutional uses to include an approximately 15,000-square-foot childcare facility and space for community use; approximately 4,250 parking spaces; 6 acres of open space; and infrastructure improvements. The original variant would include the development of the 0.8-acre parcel that is currently occupied by Authentic Church (Block/Lot 7295/002) at 3355 19th Avenue, adjacent to the project site between Eucalyptus and Winston drives. Under the original variant, the redevelopment of the 27 acres surrounding the Stonestown Galleria would be the same as the proposed project; however, the additional 0.8-acre Authentic Church parcel would be developed with an additional 150 residential units; 10,000 square feet of institutional use; and 200 parking spaces in a partially below grade parking structure.

However, as compared to the original variant, the revised variant would include 3,491 residential units (an additional 411 residential units including 200 senior housing units), an additional 411 parking spaces, 104,000 square feet less non-retail sales and service use, and no hotel use. Table 2 presents the existing, original variant, revised variant, and net change from the original variant.

The WSA calculator prepared for the land uses proposed under the revised variant provide a conservative estimate of water demand for the proposed project (see Attachment 1).

1 “Non-Retail Sales and Service Use” includes business services, catering, commercial storage, design professional, general office, laboratory, life science, non-retail professional service, trade office, wholesale sales, and wholesale storage (San Francisco Planning Code section 102, herein referred to as “planning code”).

Revised Stonestown Development Project Demand Memorandum for Preparation of Water Supply Assessment Case No. 2021-012028ENV 3 TABLE 2
PROJECT CHARACTERISTICS: ORIGINAL AND REVISED VARIANT
Project Characteristics Existing
Proposed Project Including
Authentic Church Variant
(Original Variant) Revised Variant
Net Change
from Original
Variant
Residential Use 0 3,200,000 sf Up to 3,534,000 +334,000 Retail Sales and Services Usea 760,000 sf mall
13,300 sf, 30-foot-
tall vacant theater
15,000 sf, 15- to
30-foot-tall
commercial
building
Up to 160,000 sf
710,000
d sf of the existing mall
retained
13,300 sf vacant theater,
50,000 sf CitySports building,
and 15,000 sf commercial
building to be demolished
81,700 sf net new
Up to 160,000 sf
710,000d sf of the existing mall
retained
13,300 sf vacant theater,
50,000 sf CitySports building,
and 15,000 sf commercial
building to be demolished
81,700 sf net new
No Change
Non-Retail Sales and Service
Useb
0 Up to 200,000 net new sf Up to 96,000 -104,000
Hotel 0 Up to 100,000 sf (200 rooms)
net new
0 -100,000 (-200
rooms)
Institutional Usec 30,000 sf, 30-foot-
tall church
Up to 63,000 sf
30,000 sf church demolished
33,000 sf net new; including an
approximately 15,000-square-
foot childcare facility
Up to 63,000 sf
30,000 sf church demolished
33,000 sf net new
; including an
approximately 15,000-square-
foot childcare facility
No change
Proposed Total Dwelling
Units (Approximate Number)
0 3,080 3,491 +411
Proposed Parking Number (approximate)
Vehicle parking spaces: 3,400 4,450 4,861 +411
Car-Share parking spaces 0 82 82 No Change
Open Space Area
Publicly accessible open space 1.6 acres Approximately 6 net new acres No Change Private residential open space N/A Approximately 36 square feet per unit if located on balcony, or approximately 48 square feet per unit if commonly accessible to residents, or as otherwise refined in the planning code.

No Change
Building Characteristics
Stories 1 to 3 stories 3 to 18 stories No Change
Height 15 to 65 feet 30 to 190 feet No Change
Ground floor Retail sales and
service
All blocks would include ground floor active uses, which could include any combination of retail sales and service, non-retail sales and service, institutional, or residential space facing the street No Change
NOTES
a. “Retail Sales and Service Use” is a use category that includes, but not limited to: the sale of goods, typically in small quantities, or services directly to the ultimate consumer or end user with some space for retail service on site, excluding Retail Entertainment Arts and Recreation, and Retail Automobile Uses and including, but not limited to: Adult Business, Animal Hospital, Bar, Cannabis Retail, Chair and Foot Massage, Tourist Oriented Gift Store, General Grocery, Specialty Grocery, Gym 2 Hotel, Jewelry Store, Kennel, Laundromat, Liquor Store, Massage Establishment, Mortuary (Columbarium), Motel , Non- Auto Sales, Pharmacy, Restaurant, Limited Restaurant, General Retail Sales and Service, Financial Service, Fringe Financial Service, Limited Financial Service, Health Service, Personal Service, Retail Professional Service, Self -Storage, Tobacco Paraphernalia Establishment, and Trade Shop (planning code section 102).
b. “Non-Retail Sales and Service Use” includes the sale of goods or services to other businesses rather than the end user, or that does not provide for direct sales to the consumer on site. Uses in this category include, but are not limited to: Business Services, Catering, Commercial Storage, Design Professional, General Office, Laboratory, Life Science, Non-Retail Professional Service, Trade Office, Wholesale Sales, and Wholesale Storage (planning code section 102).
c. “Institutional Use” includes Child Care Facility, Community Facility, Private Community Facility, Hospital, Job Training, Medical Cannabis Dispensary, Religious Institution, Residential Care Facility, Social Service or Philanthropic Facility, Post -Secondary Educational Institution, Public Facility, School, and Trade School (planning code section 102).
d. The 50,000 sf CitySports building would be demolished and is subtracted from the existing mall square footage to be retained.

Revised Stonestown Development Project Demand Memorandum for Preparation of Water Supply Assessment Case No. 2021-012028ENV 4 Project construction would occur in six phases over the course of approximately eight years, from 2024 to approximately 2032 (see Table 3). The first operational year is assumed to be 2027. By 2030, construction of Phases 1–3 is assumed to be completed, consisting of up to approximately 1,893 residential units (1,867,500 square feet), up to 66,000 square feet of new retail sales and service use space; up to 12,000 square feet of new non-retail sales and service use;2 and up to approximately 21,000 square feet of institutional uses.3 The revised variant would have the same construction schedule as the original variant for Phases 1 through 5, but would extend Phase 6 by approximately 3 months.

TABLE 3

PRELIMINARY ORIGINAL AND REVISED ESTIMATED CONSTRUCTION SCHEDULE Construction Phase Start Finish Duration (Months)
Phase 1 4/1/2024 1/11/2028 45
Phase 2 4/1/2025 12/22/2028 44
Phase 3 6/1/2026 10/1/2028 28
Phase 4a 4/1/2027 12/1/2030 44
Phase 5 4/1/2028 11/1/2031 43
Phase 6 4/1/2029 4/1/2032 (original)
6/30/2032 (revised)
36 (original)
39 (revised)
Total 4/1/2024 4/1/2032 (original)
6/30/2032 (revised)
96 (original)
99 (revised)
SOURCE: Brookfield Properties Development, 2022 and 2023.

NOTE:
a. The construction of the Authentic Church Variant would be accommodated within Phase 4.

The original and revised variant would meet the requirements of all applicable City and County of San Francisco ordinances related to water conservation and resources, including:
• The original and revised variant would construct potable water distribution pipelines to serve the new uses.

The existing potable water pipeline in the segments of 20th Avenue and Buckingham Way would be relocated to the proposed alignments of these streets. To reduce potable water demand, high-efficiency fixtures and appliances would be installed in new buildings comply with the state’s Title 24 requirements and the City’s Residential Water Conservation Ordinance (San Francisco Housing Code, Ch. 12A) and Commercial Water Conservation Ordinance (San Francisco Building Code, Ch. 13A). • The project site is located within a designated recycled water use area, and the original and revised variant would provide the piping needed to distribute recycled water when it becomes available, as required under San Francisco's Recycled Water Use Ordinance (San Francisco Public Works Code, Article 22). • The original and revised variant would comply with San Francisco’s Non-potable Water Ordinance (San Francisco Health Code, Article 12C) and would include the diversion and reuse of water from HVAC/cooling systems, graywater, blackwater (from commercial uses only), and rainwater for toilet and urinal flushing, cooling towers, residential laundry, drain trap priming, and irrigation or landscaped areas.

2 “Non-Retail Sales and Service Use” includes business services, catering, commercial storage, design professional, general office, laboratory, life science, non-retail professional service, trade office, wholesale sales, and wholesale storage (planning code section 102). 3 Brookfield Properties Development, 2023, Stonestown Program Summary Spreadsheet, February 7, 2023.

Revised Stonestown Development Project Demand Memorandum for Preparation of Water Supply Assessment Case No. 2021-012028ENV 5 • Landscaped areas would be installed, constructed, operated, and maintained in accordance with the Water Efficient Irrigation Ordinance (San Francisco Administrative Code, Ch. 63).

Revised Variant Water Demand
Table 4 shows the estimated daily and annual water demand for the original and revised variant by land use category. As shown, the total water use for the revised variant would be approximately 309,400 gallons per day (gpd), or 112.92 million gallons per year (gpy). Of the total water demand, 104.06 million gpy would be for indoor water use and 8.85 million gpy would be for irrigation and HVAC/cooling purposes. In addition, because the revised variant would comply with the City’s Non-potable Water Ordinance and Recycled Water Use Ordinance, other water saving measures involving water efficient fixtures and onsite reuse, could result in the availability of up to

56.38 million gpy of non-potable water to offset projected water demand. Approximately 42.94 million gpy or 38 percent of revised variant demand is expected to be met by non-potable supply. The calculations were developed using the SFPUC District Scale Non-Potable Water Calculator, Version 9.1.

TABLE 4

ORIGINAL AND REVISED VARIANT ESTIMATED WATER DEMAND
Proposed Use
Original Variant
Estimated Daily
Water Demand (gpd)
Original Variant
Estimated Annual
Water Demand (gpy)
Revised Variant
Estimated Daily
Water Demand (gpd)
Revised Variant
Estimated Annual
Water Demand (gpy)
Commercial water demand (indoor) 15,746 5,747,220 6,288 2,295,041 Multi-Family water demand (indoor)a 209,507 76,469,901 278,813 101,766,679 Landscape irrigation demand (outdoor) 6,259 2,284,409 6,259 2,284,409 HVAC/Cooling demand (outdoor)b 17,091 6,238,215 18,003 6,570,986 Total 248,700 90,739,800 309,400 112,917,200
NOTES:
a. The persons per household value of 2.36 was used instead of the default value of 2.01 in the WSA calculator. The WSA calculator’s default is based on the 2011 Retail Demand Model Update, while the 2.36 persons per household value is based on the latest U.S. Census data and consistent with the population analyzed in the environmental impact report.
b. The HVAC/Cooling demands are calculated by applying demand factors for each land use and typical usage percentages by month. This is based on the project area’s typical climate and the project sponsor’s data.

Table 5 summarizes water volumes reported in units of million gallons per day (mgd) for the original and revised variant. Note that the revised variant would not vary demands based on water year type.

Revised Stonestown Development Project Demand Memorandum for Preparation of Water Supply Assessment Case No. 2021-012028ENV 6 TABLE 5

WATER DEMAND BASED ON PROJECT PHASING FOR THE ORIGINAL AND REVISED VARIANTS (MGD) Demand (mgd) 2025a 2030 2035 2040 2045
Original Variant
Potable Demand 0 0.083 0.152 0.152 0.152
Non-potable Demand 0 0.064 0.097 0.097 0.097
Total Demand 0 0.147 0.249 0.249 0.249
Potential Potable Water Savings as Percentage of Total Demand — 41% 39% 39% 39% Revised Variant
Potable Demand 0 0.103 0.191 0.191 0.191
Non-potable Demand 0 0.075 0.118 0.118 0.118
Total Demand 0 0.178 0.309 0.309 0.309
Potential Potable Water Savings as Percentage of Total Demand — 40% 38% 38% 38% SOURCE: SFPUC District Scale Non-Potable Water Calculator, Version 9.1 NOTES:
a. Assumes first operational year is 2027.

NON-POTABLE WATER CALCULATOR
Project Summary Sheet Stonestown
Project Contact: Christie Donnelly
510-816-0761
[email protected]
Total Gross Square Footage: 5,467,863 Estimated Final Site/Building Permit Issuance Date: 1/1/2024

1. Demand and Supply Summary
Demand Met by Non-Potable Supply (gallons/year): 42,940,015 38% of total Total Annual Water Demand (gallons/year): 112,917,200
6-Month Compliance Periods
January - June July - December
Potable Make-Up Allocation (gallons/period): 1,814,459 1,822,444

2. Building Information Summary
Site 1 Site 2 Site 3 Project Total
Project / Building Name: Stonestown Stonestown
Project Address: 3251 20th Avenue 3251 20th Avenue
San Francisco, CA
Assessor's Block & Lot No. / APN: 7295-004, 005, 035, 037, 038 & 7296 - Date of Completion: 2038 -
Building Type: Mixres MIPS MIPS -
Total Building Size (GSF): 5,467,863 0 0 5,467,863
Total Lot Size (ft2): 1,432,940 0 0 1,432,940
Number of Residential Units: 3,491 0 0 3,491
Impervious Surface Above Grade (ft2): 664,590 0 0 664,590 Impervious Surface Below Grade (ft2): 436,030 0 0 436,030 Irrigated Landscaped Area (ft2): 242,870 0 0 242,870

3. Summary of Non-Potable Demands and Supplies for the Project Non-Potable Supply Estimates
Annual Supply (gpy)
Onsite Alternate Water Sources Site 1 Site 2 Site 3 Project Total Graywater: 0 0 0 0
Blackwater: 55,494,848 0 0 55,494,848 (includes GW)
Condensate: 887,083 0 0 887,083
Rainwater/Stormwater: 0 0 0 0
Other Supplies: 0 0 0 0
TOTAL: 56,381,931 0 0 56,381,931
Non-Potable Demand Estimates
Annual Demand (gpy)
Project Non-Potable Demands Site 1 Site 2 Site 3 Project Total Toilets/Urinals: 20,516,371 0 0 20,516,371
Drain Trap Priming: 0 0 0 0
Irrigation: 2,284,409 0 0 2,284,409
Clothes Washing: 13,568,249 0 0 13,568,249
HVAC/Cooling: 6,570,986 0 0 6,570,986
Other Demands: 0 0 0 0
TOTAL: 42,940,015 0 0 42,940,015
7/5/2023 7. Project Summary Page 1 of 2

4. Project Phasing
SITE 1: Stonestown SITE 2: SITE 3: Project Total
15-Year Timeframe
(enter dates on Tab 1)
NP Offset
Supplies
(gpy)
Selected NP
Demand
(gpy)
NP Offset
Supplies
(gpy)
Selected NP
Demand
(gpy)
NP Offset
Supplies
(gpy)
Selected NP
Demand
(gpy)
NP Offset
Supplies
(gpy)
Selected NP
Demand
(gpy)
Re-Used Non-
Potable Supplies
(gpy)
2038 56,381,931 42,940,015 0 0 0 0 56,381,931 42,940,015 42,940,015 2039 56,381,931 42,940,015 0 0 0 0 56,381,931 42,940,015 42,940,015 2040 56,381,931 42,940,015 0 0 0 0 56,381,931 42,940,015 42,940,015 2041 56,381,931 42,940,015 0 0 0 0 56,381,931 42,940,015 42,940,015 2042 56,381,931 42,940,015 0 0 0 0 56,381,931 42,940,015 42,940,015 2043 56,381,931 42,940,015 0 0 0 0 56,381,931 42,940,015 42,940,015 2044 56,381,931 42,940,015 0 0 0 0 56,381,931 42,940,015 42,940,015 2045 56,381,931 42,940,015 0 0 0 0 56,381,931 42,940,015 42,940,015 2046 56,381,931 42,940,015 0 0 0 0 56,381,931 42,940,015 42,940,015 2047 56,381,931 42,940,015 0 0 0 0 56,381,931 42,940,015 42,940,015 2048 56,381,931 42,940,015 0 0 0 0 56,381,931 42,940,015 42,940,015 2049 56,381,931 42,940,015 0 0 0 0 56,381,931 42,940,015 42,940,015 2050 56,381,931 42,940,015 0 0 0 0 56,381,931 42,940,015 42,940,015 2051 56,381,931 42,940,015 0 0 0 0 56,381,931 42,940,015 42,940,015 2052 56,381,931 42,940,015 0 0 0 0 56,381,931 42,940,015 42,940,015 This offset analysis assumes the full year of supplies is available to offset non-potable demands. Some scenarios may require storage to allow excess supplies from one part of the year to be used in later months with available demand.
0 10,000,000
20,000,000
30,000,000
40,000,000
50,000,000
60,000,000
2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 Gallons per Year
Year
Onsite Supplies and Non-Potable Demand Over 15-Year Timeframe Total Onsite Supply Total Non-potable Demand
0 1,000,000
2,000,000
3,000,000
4,000,000
5,000,000
6,000,000
January February March April May June July August September October November December Gallons Per Month
Selected Onsite Supply vs. Selected Non-Potable Demand (All Sites On-Line) Total Onsite Supply Total Non-potable Demand
7/5/2023 7. Project Summary Page 2 of 2

CleanPowerSF Sfpuc CommissionOctober 24, 2023

CleanPowerSF Sfpuc Commission
October 24, 2023