MEMORANDUM
DATE: April 30, 2026
TO: Commissioner Joshua Arce, President
Commissioner Stephen E. Leveroni, Vice President
Commissioner Avni Jamdar
Commissioner Kate H. Stacy
Commissioner Meghan Thurlow
THROUGH: Dennis J. Herrera, General Manager
FROM: Steven R. Ritchie, Assistant General Manager, Water
SUBJECT: Onsite Water Reuse Program Update – FY 24/25
Onsite Water Reuse Program Key Updates
The City and County of San Francisco implements an oversight and management program of onsite non- potable water systems to ensure the safe design, installation, and ongoing operation of these systems.
The San Francisco Public Utilities Commission (SFPUC) actively participates in the permitting program by approving water budget applications, managing the Cross -connection Control Program, and providing technical assistance on navigating the permitting process. The SFPUC also develops partnerships with the private sector to educate and assist with the implementation of onsite water systems. Onsite water systems are contributing to the SFPUC’s OneWaterSF approach to manage our resources efficiently.
Notable program highlights led by SFPUC for FY 24-25 include:
• Updated several resources published on www.sfpuc.gov/npo:
o Onsite Water Reuse Lessons Learned Guidebook: Tips
and Recommendations from the Field for Successful
Design, Operations, Maintenance, & Implementation
o Case Studies of Innovative Water Reuse and Resource
Recovery Projects
o Onsite Water Reuse Guidebook
o Guidebook for Commissioning an Onsite Water Treatment System
• Published the Independent Advisory Panel Report on Single- Family Water Reuse Applications Report
• Hosted and presented a webinar on Findings from the
Independent Advisory Panel for Single-Family Reuse Applications Report
• Created and published the Water Resources Division Fiscal Year 2024-2025 Annual Report
Background: San Francisco’s Onsite Water
Reuse Program
In September 2012, the City and County of San Francisco adopted the Non-potable Water Ordinance, adding Article 12C to the San Francisco Health Code. San Francisco is the first municipality to establish an ordinance and mandate the
collection, treatment, and use of alternate water sources such as graywater, rainwater, stormwater, blackwater, and
foundation drainage for non-potable applications such as toilet flushing and irrigation.
The ordinance established the roles and responsibilities of the SFPUC, San Francisco Department of Public Health
(SFDPH), San Francisco Department of Building Inspection (SFDBI), and San Francisco Department of Public Works
(SFPW) in the oversight of onsite non- potable water systems in buildings.
The ordinance requires new development projects that apply for a site permit after January 1, 2022 of 100,000 gross square feet or more to install and operate an onsite water reuse system. The required alternate water sources and required non-potable uses are based on development project type. For commercial buildings, the project must meet its toilet and urinal flushing and drain trap priming demands through the collection, treatment, and use of available blackwater and condensate. For residential and mixe d-use buildings, the project must meet its toilet and urinal flushing, irrigation, clothes washing, and drain trap priming demands through the collection, treatment, and use of available graywater and
condensate. The requirements apply to both development
projects consisting of a single building or multiple buildings.
New development projects that have applied for a site permit before January 1, 2022 of 250,000 gross square feet or more are still required to install and operate an operate water reuse system. For the required building types, the project must meet its toilet and urinal flushing and irrigation demands through the collection, treatment, and use of available graywater,
rainwater, and foundation drainage.
To continuously improve inter -agency collaboration, the SFPUC and SFDPH meet monthly to review the status of
onsite water reuse projects and all four City agencies meet quarterly to share updates.
For more information, visit www.sfpuc.gov/npo.
Onsite Water Reuse Project Case Studies
Figure 1. Salesforce Tower
Salesforce Tower at 415 Mission Street:
Salesforce Tower is a 61- story office building and the second- tallest building in California. Salesforce Tower has a rainwater harvesting system as well as a 30,000 gallon per day
blackwater recycling system. Both water reuse systems are used for toilet and urinal flushing water, irrigation of trees on the plaza and landscape on the 5th floor, and cooling tower make-up water. The system is in operation and estimated to save 5.6 million gallons of water annually.
Figure 2. Energy Center San Francisco – BART Foundation Drainage Project
Energy Center San Francisco – BART Foundation
Drainage Project:
Energy Center San Francisco (ECSF) is a district steam
heating system operator. It provides steam for heating hot water and provides process steam to hotels and buildings in
downtown San Francisco. Driven by their commitment to
water use efficiency, ECSF partnered with BART on a project to reclaim foundation drainage at the Powell Street BART station and redirect it to its District Energy Plant, located nearby on Jessie Street, where it could be used in the district “steam loop,” the network of underground pipes. ECSF’s
onsite water treatment system includes a raw water collection tank with a coarse strainer, microfiltration (MF), and closed- circuit reverse osmosis (CCRO). The water also undergoes softening to remove minerals that interfere with the process of steam production. The system is in operation and saves over 30 million gallons of water annually.
Figure 3. San Francisco Museum of Modern Art
San Francisco Museum of Modern Art:
The San Francisco Museum of Modern Art (SFMOMA) is a
world-renowned modern art museum. The museum’s onsite
water system captures rainwater and treats it through a 50- micron filtration filter and a 20- micron bag type filter. After treatment, the water is disinfected and distributed for non- potable applications, which includes toilet flushing, make- up water for the cooling towers, and drip irrigation of the gardens and living wall. Overall, the system saves 365,000 gallons of potable water annually.
Additional case studies that feature San Francisco’s onsite water reuse projects, as well as other innovative water
recycling and resource recovery projects across the globe are available at www.sfpuc.gov/npo.
Potable Water Offsets
To date, there are 121 total water budget applications
approved by the SFPUC for onsite water systems. As of
November 2025, there are 58 operating onsite water systems, the majority of which are capturing, treating, and using rainwater, stormwater, and/or condensate for non- potable demands such as toilet flushing and/or irrigation. 7 of the operating systems are graywater treatment systems. There are 2 operating blackwater treatment systems, one at the Salesforce Tower and another at Mission Rock. There are 2 operating foundation drainage reuse systems, one at Moscone Center and another at Energy Center San Francisco. More information on these projects and others can be found in the case studies report posted on www.sfpuc.gov/npo.
The current potable water offset for the Onsite Water Reuse Program is 65,637,410 gallons per year, which is equivalent to
0.16 million gallons per day (MGD). This is equivalent to offsetting the average annual home water use of 3,967 San Franciscans, which is the equivalent of filling 98 Olympic-sized pools. By 20 50, the expected potable water offset will be approximately 1.55 MGD, which is equivalent to offsetting the average annual home water use of 30,000 San Franciscans.
An estimated 69% of the total number of operational projects are implementing stormwater or rainwater harvesting systems to comply with the Stormwater Management Ordinance
(SMO). Figures 5 and Table 1 provide an overview of San Francisco’s onsite water reuse projects.
Figure 5. San Francisco's Voluntary, Mandatory, and Grant -Supported Onsite Water Reuse Projects as of FY 24-25
Onsite Water Reuse Grant Program
The SFPUC’s Onsite Water Reuse Grant Program provides
grant funding to encourage retail water users to reduce SFPUC water supply usage by collecting, treating, and using alternate water sources including rainwater, stormwater, graywater, foundation drainage, air conditioning condensate, and blackwater for non- potable uses such as toilet flushing, irrigation, and cooling tower makeup.
Grant applicants must demonstrate the ability to achieve at least one of the following thresholds to eligible for grant funding:
• Projects that replace at least 450,000 gallons of
SFPUC water per year are eligible for grant funding up
to $200,000; or
• Projects that replace at least 1,000,000 gallons of
SFPUC water per year are eligible for grant funding up
to $500,000; or
• Projects that replace at least 3,000,000 gallons of
SFPUC water per year are eligible for grant funding up
to $1,000,000.
The SFPUC is also promoting innovation through the Grant Program. For example, the SFPUC is providing grant funds to breweries to collect, treat, and reuse process water generated onsite. Collecting and reusing process water onsite can provide significant offsets to potable water usage as breweries use large quantities of water for cleaning tanks, bottles, and equipment. The SFPUC’s water recycling program specifically for breweries includes guidance and requirements for water characterization, treatment, and ongoing monitoring to ensure the water is safe for the intended reuse.
Additionally, the SFPUC is incentivizing the implementation of wastewater heat recovery systems within development
projects installing onsite water reuse systems. The Grant Program requires all applicants to estimate the potential energy offset that can be achieved with wastewater heat recovery. In addition, mixed- used and multi -family buildings that are grant recipients are required to implement wastewater heat recovery. SFPUC’s is in the process of gathering more information about the potential benefits of these systems in terms of how they can reduce the overall energy demands of buildings with onsite water systems. SFPUC is also in process of revising its Grant Program Rules to encourage greater program participation.
555 Bryant is the most recent recipient of an onsite water reuse grant. The new development project has completed
construction and will be undergoing the Conditional Start -Up Phase before Final Operation. The project has installed a graywater treatment system to meet non- potable water
demands for toilet flushing, irrigation, and clothes washing.
The project will offset approximately 3.6 million gallons of SFPUC water each year. The project will also install a
wastewater heat recovery system, which will reduce the
energy consumption of the onsite water treatment system by using the extracted thermal energy to pre -heat the potable water supplied to the building’s water heater.
National Blue Ribbon Commission for Onsite
Water Systems
The SFPUC has been on the forefront of innovation in
advancing onsite water reuse in North America. As chair of the National Blue Ribbon Commission for Onsite Water Systems
(NBRC), the SFPUC is leading a collaborative of utilities and public health agencies from 15 states, the District of Columbia, the city of Toronto, the city of Vancouver, US EPA, and US Army Engineer Research and Development Center.
Supported by the WateReuse Association, the NBRC has
developed resources to support implementation of onsite water systems and foster strong collaborations between water and wastewater utilities and public health agencies. The NBRC has made significant research contributions as well as advanced policies and regulations for onsite water reuse nationally.
The NBRC embraces a risk -based framework to onsite water reuse by addressing not only log reduction targets and
appropriate treatment trains, but critical control point monitoring, permitting, and oversight and management.
Building on the N BRC’s 2023 document Health Risk -based Benchmarks for Onsite Treatment of Water , the NBRC
published a new document in 2025 titled Recommended
Pathogen Reduction Targets for Onsite Water Systems . T he 2025 document is an update to the NBRC’s 2017 guidance for onsite water systems used in commercial, multi -family, and mixed-use buildings for landscape irrigation and indoor non- potable use. The NBRC’s 2025 recommendations for LRTs
reflect updated information on reference pathogens and the most current reference pathogen dose- response models. The updated LRTs are available for consideration by jurisdictions seeking to adopt new OWS oversight
and management programs.
In addition, the SFPUC continued to co-chair Building
Infrastructure Locally for Decentralized Water Systems (BILD).
BILD is a partnership among NBRC, WateReuse Association, US EPA, regulators, utilities, design engineers, product manufacturers, operators, non- governmental organizations, and academia working together in the spirit of collaboration to implement decentralized water infrastructure.
For more information about the NBRC and BILD, visit
www.watereuse.org/nbrc and www.watereuse.org/nbrc/bild.
cc: Taylor Nokhoudian, SFPUC
Megan Zheng, SFPUC
Ken Payne, SFPUC-WQD
Mark Johnson, SFPUC-WQD
Steve Panelli, SFDBI-PID
David Gordon, SFDBI-PID
Doug Obana, SFDPH-EH
Rochelle Yap Veloso, SFDPH-EH
Eleanor Tang, SFPW
Jon Kwong, SFPW