San Francisco Cross Connection Control Program


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

Cross-Connection Control (Backflow Prevention) At a Glance

To protect the City’s drinking water system from contamination caused by backflow. 

Who Must Comply?
Owners of properties with potential unprotected cross connections and/or
backflow prevention assemblies. 

Municipal Code
Health Code, Article 12A 

Rules and Regulations Governing Water Services to Customers: Section G – Cross-Connection Control

See our frequently asked questions. 

Cross-Connection Control Program
(650) 652-3199 

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. 

If you are a backflow prevention assembly tester, scroll down further on this web page to “I’m a backflow prevention assembly tester.”

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 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: