Backflow Prevention & Testing

Beginning July 1, 2023

The City has partnered with Backflow Solutions Inc or BSI Online, a third party contractor to manage the Backflow/Cross Connection Control Program.  BSI Online provides a web-based tracking program and a more efficient and cost effective means of managing the inventory and state testing and reporting requirements of backflow prevention assemblies.

Backflow Prevention

To protect the public water mains from potential contamination by non-potable "used water" that could be drawn in from the private customer, the City requires installation of a backflow prevention device on new services.


All installed devices must be tested annually by a certified backflow prevention tester and immediately repaired if necessary. During backflow testing, a certified plumber will open and close the valves of the backflow prevention device or assembly to make sure it is functioning as it should. The plumber will assess the valves for leakage, gauge movement and other telltale indicators of a malfunction.

If the valves are working correctly, you'll be all set - if not, the plumber can most likely do some quick repairs to keep your home's water safe and clean. Notice letters are sent to customers each year regarding this testing requirement by Backflow Solutions Inc. These notices and additional device information are also available on their Customer Portal available at

Your certified tester will need to upload the test report to your customer account to BSI online . There is a fee associated with uploading. Testers can also provide additional information on the device if a failure occurs or if the device has to be replaced.

If you are unsure what testers are certified for the City of Cotati, please contact BSI Online at 888-966-6050 for an updated list of certified testers within the City.

Untested Devices

Devices that are not tested by the deadlines as outlined within the letter provided will be tested by the City.  The cost of the test and any repairs needed for the device is billed to the customer plus additional administrative processing fees. 


For more information, call BSI Online at 888-966-6050 or Administrative Services at 707-665-3631.