Cross Connection Control Program & Backflow Testing

What is cross-connection?
A cross-connection is any actual or potential connection between the public or consumer’s potable water system and any non-potable source or substance that presents a hazard to the quality of the public or consumer’s potable water system. Therefore, cross-connection control is the management or “control” of these cross-connections to protect public safety by preventing backflow incidents within the public or water consumer’s potable water system.

What is backflow?
Typically, water will flow from the public water supply to the consumer’s plumbing distribution system. Backflow is the undesirable reversal of this flow of water and undesirable substances from the non-potable source to the potable source.

Annual Testing of Backflow Prevention Assemblies
The City of Davis requires all backflow devices be tested annually by a certified backflow prevention tester and be repaired if necessary (City of Davis Municipal Code Article 39.04 and the State of California Cross Connection Control Handbook). This annual testing helps eliminate actual or potential cross connections into public water supplies. 

Each year, notice letters are sent to customers with backflow prevention assembly to notify them of the testing deadline and how to work with a certified tester to submit the Test and Maintenance Report. 

The City of Davis has partnered with Backflow Solutions, Inc (BSI) to assist in with State required cross-connection/backflow tracking regulations, including sending notifications and managing required data on behalf of the City.  

As of June 15, 2025, all completed backflow prevention tests must be submitted to BSI through their website: https://bsionline.com/. The City will no longer accept tests after this date. Please note that testers must register with BSI before submitting any reports. 

Backflow Solutions Inc. (BSI) resources

• Tester Company Login Portal
• Water Customer Portal
• BSI Online Blog
• Backflow Academy

Below, please find some Backflow Testing Frequently Asked Questions.

I received a letter that I am required to test my backflow prevention assembly, but I can only have it tested by a "certified tester." Where can I find that list? 

In California, only certified backflow assembly testers can test the assembly and submit the Test and Maintenance Report to BSI. A list of certified testers is provided by BSI on their website:

I received a letter that I am required to test my backflow prevention assembly, but I don't know why I've received this letter // no longer have the assembly on my property // there's an error in the letter. What do I do?

If you no longer have the assembly on your property, if you do not know why you received the letter regarding backflow assembly testing, or you would like to notify the City of an error in the letter, please contact Jared Davis, Water Distribution Programs Supervisor, with the City of Davis Public Works Utilities & Operations Department at 530-757-5686 or pwweb@cityofdavis.org. 

I've had my backflow assembly tested, and I've been told it's not functioning properly. What do I do?

You will be required to repair or replace the assembly as necessary (based on the findings of the certified tester) and have the assembly re-tested. Failure to comply with the program may result in termination of water service.

If you have a question that is not included above, please contact the City of Davis Public Works Utilities & Operations at 530-757-5686 or pwweb@cityofdavis.org.