Non-Potable Water Systems

In a dense, urban center like San Francisco, the use of on-site alternate water sources is key in protecting against future water shortages. This includes a range of approaches from rainwater harvesting for irrigation to blackwater treatment and reuse for toilet flushing. An example of a building employing these technologies is the San Francisco Public Utilities Commission (SFPUC) headquarters building located at 525 Golden Gate Avenue.

In September 2012, the San Francisco Board of Supervisors adopted an ordinance establishing (pdf) the Non-potable Water Program. Through this program, local regulations (pdf) are being developed and guidelines established (pdf).

The Non-potable Water Program includes a permitting process and operational requirements for any new commercial, multi-family, and mixed-use developments in San Francisco that collect, treat, and reuse water for toilet flushing, irrigation and other non-potable uses.

The process establishes a collaborative mechanism for input and oversight from the San Francisco Department of Public Health (SFDPH), the SFPUC and the San Francisco Department of Building Inspection (SFDBI) on the design, construction, and operation of an on-site water treatment system. The process from project conceptualization to startup is summarized below. More details are described in the step-by-step guidebook available on the SFPUC website and SFDPH's Rules and Regulations for On-site Non-potable Water Treatment and Use Systems (pdf).

Permit Process and Operational Requirements

1. Submit a Non-potable Project Application (pdf) to SFPUC


2. Submit an Application for Permit to Operate On-Site Non-Potable Water Treatment and Use System and Engineering Report along with the appropriate fee to SFDPH for review and approval.


3. Submit Plumbing Plans to SFDBI


4. Construct System


5. Submit a Construction Certification Letter to SFDPH


6. Have a certified specialist complete a cross-connection test


7. SFDPH will issue a permit to operate. Depending on source water, end uses and system design, each system progresses through one or more of the following three permit modes: Start-up, Temporary Use, and Final Use.


• Under the Start-up Mode Permit, operators fine tune and trouble-shoot the system. Non-potable water treated on-site bypasses to the sewer while potable water is supplied to all end use fixtures.


• Upon demonstration of the satisfactory performance of the system under the Start-up Mode Permit, SFDPH may issue a Temporary Use Mode Permit. The on-site water treatment system supplies treated water to approved, non-potable end use fixtures.


• Following verification of compliance with sampling, analysis and reporting requirements under the Temporary Use Mode Permit, if applicable, SFDPH may issue a Final Use Permit.


• Throughout all permit modes, the system operator conducts specified inspections and tests, submits routine monitoring and annual monitoring reports to SFDPH, and communicates system malfunctions to SFDPH in accordance with the rules and regulations and the permit requirements.

For questions or additional assistance, please email DPH.NonPotable@sfdph.org.