General Information

Notice: If you have recently been notified that you are required to install a backflow prevention device, visit our Backflow Installation Instructions page for instructions and other information to help you through the process!  Special information for private well owners is also included.

Backflow Prevention Device and Who Needs One

Backflow devices are an integral part of the City’s Cross Connection Control Program. They help to ensure that no contaminants of any kind (chemicals, debris, reclaimed water, etc.) enter the potable water system. 

Backflow devices are owned by the customer and regulated by the State through the City of Palo Alto.  While it is primarily business customers who are required to have these devices, some residential properties need them, also. 
The State of California Department of Health Services provides regulations for the City and our customers through California Code of Regulations, Title 17. These regulations spell out the types of services that require backflow devices. 

Check out our general guide to understanding and installing backflow prevention devices.

Visit our "Go Green" page to understand important backflow issues related to using stormwater "rain barrels", recycled "gray water" and solar water heaters.

Backflow Device Testing Procedures

Once backflow devices are installed, the devices must be tested on an annual basis and test results must be submitted to the City. Your City approved tester will place a serialized, color-coded, metal tag on your device that will be changed out each year.

The City will only accept test reports from testers who have registered with the City of Palo Alto and have provided the Cross Connection Control Program with copies of their State certification and calibration reports. Please see our list of registered testers

Testers wishing to register with the City may contact the Cross Connection Control Program office at (650) 496-5926 or via email.

All tests results must be submitted on a City of Palo Alto test form.

Questions about the backflow prevention device survey, testing, or test reporting? Please contact the City's Cross-Connection Control Office at (650) 496-5926.

Trying to install a backflow prevention device?

If you have already looked for the correct location for your device but still need further assistance, our Building Department can assist you. Please contact one of our two inspectors (but not both!) with your specific questions:

  • Brent Hipsher (email or phone (650) 617-3173)   or
  • Paul Schultz (email or phone (650) 617-3110)

Please do not ask plumbers bidding on your job to contact the inspectors.  Only you or a plumber who is already contracted for the work should be in contact with the inspectors.  This eliminates confusion and allows our staff to give you more efficient service.

Please take a look at the City’s Backflow Rules and Regulations.

Backflow Standards