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Onsite Water Reuse

Contact Email: nonpotable@sfwater.org

IMPORTANT: Draft Rules & Regulations Now Open for Public Review
The San Francisco Department of Public Health (SFDPH) has published draft Rules and Regulations Regarding the Operations of Onsite Treated Non-potable Water Systems. The public comment period runs from September 24 to October 26, 2026.

JOIN OUR PUBLIC WORKSHOP: SFPUC and SFDPH will host a public workshop on Wednesday, October 14, 2026, at 10:30am PT at 525 Golden Gate Ave and available virtually. The workshop will provide an overview of the Rules and Regulations and an opportunity to ask questions and submit public comments.

View the draft Rules and Regulations, submit comments, and RSVP for the workshop.
 

Purpose

The Onsite Water Reuse Program allows for the collection, treatment, and use of alternate water sources for non-potable applications in individual buildings and at the district-scale.

Who Must Comply?

Onsite water reuse systems are required for new development projects of 100,000 gross square feet or greater in San Francisco.

technician adjusting a pipe fitting

Onsite water reuse systems represent a significant opportunity to transform the way water is managed in buildings. By matching alternate water sources with the right end use, such as irrigating landscapes and flushing toilets and urinals, onsite water reuse systems offset valuable potable water supplies and unlock the potential for more resilient and sustainable water management. The SFPUC administers the Onsite Water Reuse Program, which allows for the collection, treatment, and use of alternate water sources for non-potable applications in individual buildings and at the district-scale. Properties with onsite water reuse systems are required to obtain a permit from San Francisco Department of Public Health. San Francisco is also part of a national effort through the National Blue Ribbon Commission to overcome barriers to onsite water reuse.

Requirements

Onsite water reuse systems are required for new, large development projects in San Francisco. Recently amended in 2021, Article 12C of the San Francisco Health Code (commonly known as the Non-potable Water Ordinance) requires the following:

  • New development projects that apply for a site permit after January 1, 2022 of 100,000 gross square feet or more are required to install and operate an onsite water reuse system.
  • New development projects of 40,000 gross square feet or more are required to submit water budget calculations assessing the supply available from the required alternate water sources and the demand from required non-potable uses, outlined above. It is not required to install and operate an onsite water reuse system.

Required Alternate Water Sources and Uses

Building TypeRequired Alternate Water SourcesRequired Non-potable Uses
Commercial
  • Onsite Wastewater
  • Condensate
  • Toilet and Urinal Flushing
  • Drain Trap Priming
Residential and Mixed-Use
  • Graywater
  • Condensate
  • Toilet and Urinal Flushing
  • Drain Tap Priming
  • Irrigation
  • Clothes Washing (cold water only)

Note: Requirements for projects that submitted a site permit after January 1, 2022

Diagram of a multi-story residential building illustrating onsite water reuse sources. Arrows point from labeled sources into the building: (1) condensate—water vapor collected from air conditioning systems; (2) rainwater—precipitation collected from roofs and above-grade surfaces; (3) stormwater—precipitation collected from at or below grade surfaces; (4) foundation drainage—nuisance groundwater from dewatering operations; (5) graywater—wastewater from clothes washers, bathtubs, showers, and bathroom sinks; and (6) onsite wastewater—wastewater from toilets, urinals, and kitchen sources such as sinks or dishwashers, commingled with graywater. The building section shows multiple floors with plumbing connections indicating collection and reuse pathways.

Interface with DBI's Building Permit Process 
Development projects planning to install an onsite water reuse system must submit their Water Budget Documents to SFPUC prior to submitting a building permit application to DBI. Learn more by reading about the two submittal processes.

Grant Program
SFPUC’s Onsite Water Reuse Grant Program provides funding to support the implementation of onsite water reuse systems in the city. Depending on expected water savings, projects may be eligible for grant funding from $200,000 to $1,000,000, depending on potable offset. For more details, read the Grant Program Rules.

Applications will be temporarily paused as of August 1st, 2026, while program rules are updated; the grant program is expected to reopen by late 2026.

 

Capacity Charges and Excess Use Charges

Effective February 1, 2017, customers with onsite water reuse systems may receive an adjusted water and wastewater capacity charge. This adjustment will accurately assess capacity charges for buildings with onsite water reuse systems by charging new users only for the demand placed on SFPUC water and wastewater systems.

SFPUC also implements the NPO Excess Use Charge Program for new development projects required to comply with Article 12C. More info can be found at sfpuc.gov/NPOExcessUse.

For more guidance on how to implement an onsite water reuse system in San Francisco, please see the Onsite Water Reuse Program Guidebook.

Read the SF Onsite Water Reuse Guidebook.