Backflow Prevention Assembly Testing Notice of Grace Period
In response to the novel coronavirus (COVID-19) emergency, WQD extended testing deadlines by one month or until 30 days after the lifting of the city’s Shelter-In-Place Order. Now that the order’s restrictions are being eased, due dates for February through May have been extended to July 31, but starting with June, due dates have reverted to the end of the test month. Please email questions to backflow@sfwater.org. Stay safe.
Annual testing of backflow prevention assemblies is essential for the protection of the public water supply, and backflow prevention assembly testers are considered essential workers. Like all California residents, testers are required to follow social distancing guidelines while outside their homes and must maintain a distance of at least 6 feet away from other people. If you have concerns about social distancing during the testing of your assembly/ies, please contact your testing company or email backflow@sfwater.org.
Information about the coronavirus emergency can be found at the following websites:
If you have questions, please email backflow@sfwater.org, and we will respond as soon as we are able.

The City and County of San Francisco has a cross-connection control program to protect the City’s drinking water distribution system from contamination caused by backflow. This program was established through the City’s Backflow Prevention Ordinance, adopted in 1984. Under normal conditions, water from the distribution system flows into a consumer’s premises. When backflow occurs, water from the consumer’s premises flows into the distribution system. If that water is contaminated because of activities on the consumer’s premises (for example, addition of rust-inhibiting chemicals to a boiler or use of photo-processing chemicals), the water can carry contaminants into the distribution system, possibly causing illness or even death.
The City’s cross-connection control program is administered by the Water Quality Division of SFPUC and the Environmental Health Branch of the San Francisco Department of Public Health, in coordination with the Plumbing Inspection Division of the Department of Building Inspection.
Do the requirements apply to me?
If your property has a potential cross-connection or hazard (for example, boiler, chemical feed equipment, dedicated irrigation, an interconnected fire sprinkler system, or building height 40 or more feet above the point of connection/water meter), then the requirements of the Backflow Prevention Ordinance apply to you. You are required to install an approved backflow prevention assembly and have it tested annually.
How do I comply?
All potential cross-connections must be protected with an approved backflow prevention assembly. To be approved for use in San Francisco, an assembly must be on the “Approved Backflow Prevention Assemblies” list developed by the University of Southern California Foundation for Cross-Connection Control and Hydraulic Research. The assembly may not be modified or installed in a manner that differs from the configuration tested and approved. New assemblies must be tested immediately after installation and once a year thereafter. After the initial test, Water Quality Division will send you a notice when annual testing is due. All testing must be performed by an authorized backflow prevention assembly tester.
For additional information about backflow prevention, see the Consumer Guide to Backflow Prevention and other resources listed at the bottom of this web page.
I’m a backflow prevention assembly tester. What do I need to know?
Testers must be permitted by the Department of Public Health. Certification requirements are listed on its website.
Need help?
Be sure to check the Consumer Guide to Backflow Prevention and additional program resources listed below.
If you have questions or need additional assistance, contact the Cross-Connection Control Program at
backflow@sfwater.org or (650) 652-3199 between 8 AM and 5 PM.
These resources are available to help you comply with San Francisco’s Cross-Connection Control requirements:
Consumers and Contractors
Backflow Prevention Assembly Testers and Test Companies: