Backflow & Cross Connection Control

Cross Connection control is a vital part of protecting our drinking water. As water passes through the distribution system to all buildings within that system, it is important to ensure it is safe. A cross-connection (i.e., opportunity for substances other than drinking water to enter the plumbing) can threaten the quality of our drinking water in the distribution system. The City of Bainbridge Island requires that all cross-connections or potential cross-connections have a backflow preventer installed and tested annually.

General Information

General information may be found on our Cross Connection Control webpage.

Backflow Preventer Choices & Requirements

Visit the Backflow Preventer Choices and Requirements page for information on types of backflow preventers and specific applications.

City Hired Backflow Testing Program

The City provides annual testing for backflow devices at a lesser cost than contracting a tester privately.  The City's contracted tester will provide testing services and report back to the City as well as the home owner what the results of testing were.  The cost is then billed directly to the customer through their regular water bill the month after testing occurs.  This is the most economical and convenient way to maintain backflow assembly certification. 

(Note: due to placement of some backflow devices inside buildings, the City's contracted tester may need to contact the home/business owner to make an appointment for testing.)

Regulations & Forms

State regulations, required permits, state certified testers, backflow assembly test report form.

View Regulations, & Forms page for:

• COBI Backflow Assembly Test Report Form
• Hold Harmless Agreement
• Washington State Certified Backflow Assembly Testers List

Testing Questions & Answers

Check out frequently asked questions about cross connection control.

Stay in the Know

Sign-up for the City's Notify Me listserv to stay on top of program requirements, changes, testing schedules, etc., and select Backflow Testing.

More Information

For answers to specific cross-connection control questions, please contact the cross connection control specialists at Operations and Maintenance by email or phone (206.842.1212).