Skip to page contents
City of Bellingham, WA
Contact Us Site Map
You are here: Home) Services ) Utilities ) Water Quality) Cross-Connection Control) Backflow Requirements and Types

Backflow Requirements and Types

Backflow Preventer

The City of Bellingham requires a backflow preventer on any cross-connection or potential cross-connection. The backflow preventer may be required on the water service line, within the building, or in both locations. The backflow preventer you choose must be listed on the Washington State Department of Health's Approved Backflow Prevention Assembly List. Assemblies not currently listed must have been listed at the time of the original installation.

After the initial inspection and testing of all newly installed backflow preventers, the water customer is required to have the backflow preventer tested on an annual basis by a certified Backflow Assembly Tester (BAT).

Backflow Preventer Types

What type do you need?

The level of protection required is determined by the degree of hazard as outlined in the Washington Administrative Code (WAC) for specific types of use. The general guidelines include:

High Hazards: City of Bellingham accepts Air Gaps(AG) and Reduce Pressure Backflow Assemblies (RPBA) as protection for different types of high hazards including the following:

Low Hazards: For low hazards including fire systems and irrigation systems, City of Bellingham accepts double check detector and double check valve assemblies, pressure vacuum breaker assemblies and atmospheric vacuum breakers as types of protection.

Backflow Preventer Inspection

City of Bellingham inspects backflow assemblies upon installation and conducts periodic re-inspections on all existing assemblies. New assemblies must be tested by a State of Washington certified Backflow Assembly Tester prior to putting into service. A copy of the test report must be provided to the City of Bellingham.

 Backflow Preventer Annual testing

All backflow preventers must be tested annually and after repair, relocation, or replacement by a State of Washington certified Backflow Assembly Tester (BAT). A copy of the test report must be provided to the City of Bellingham. 

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

M 9/16/2015

Top of Page ^ Top of page