Cross Connection Control FAQ

Why an annual test on the backflow prevention assembly?

Backflow prevention assemblies are installed to protect our drinking water from potential source of contamination. The Washington State Administrative Code requires testing by a certified Backflow Assembly Tester ( BAT ) to ensure that they are functioning as designed.

Who can test backflow prevention assemblies?

Only a State of Washington certified Backflow Assembly Tester (BAT) can perform the test. Certified testers can be found on websites and in publications such as the yellow pages. An Official listing of certified testers is kept by Washington Certification Services.

Each tester is responsible for providing the City with copies of their current State certification and test equipment calibration certificates. We cannot accept test reports from testers that have not provided this information. 


for 1) Partial List of Local Certified BAT's, 2) COBI Backflow Assembly Test Report Form, 3) Hold Harmless Agreement.

What will happen if I don't test my backflow prevention assembly?

To ensure that your backflow prevention assemblies are functioning as designed, it is important to the City's water system to have testing performed annually. Failure to test an assembly increases the risk that the assembly will fail to protect our water supply.

The City of Bainbridge Island send out reminder notifications about backflow assembly testing requirements to it's water customers. However, it is the water service customer who is responsible for ensuring that the assemblies are tested on time. 

More Information

For answers to specific cross-connection control questions, contact the cross connection control specialists at the Operations Division of the Public Works Department or email.
Operations & Maintenance
7305 NE Hidden Cove Road
Bainbridge Island, WA 98110