Onsite Water Reuse

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.

NEW 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. 
• 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 mixed-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 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.

Capacity Charges and Excess Use Charges

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

Additionally, the SFPUC is currently implementing 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.