What is the purpose of a backflow assembly?

To protect the public health. The Washington state Department of Health (DOH) requires a backflow assembly to protect public or private water systems from contamination which may cause illness and possible death of the people who use the water from that potable water system. (WAC 26-290). It’s the law according to Washington administrative code.


What does a backflow assembly do?

It prevents water from flowing backwards. A backflow assembly may have one to three check valves which allow water to flow in only one direction. The assembly, also called a backflow preventer, prevents the undesirable reversal of water or other substances into the potable water system.


Why does the backflow assembly need to be tested and how often?

To insure that it is functioning properly. Backflow prevention assemblies must be tested annually, when installed, after repair, relocation, or replacement. (WAC 246-290-490(7))


Who may test and repair backflow assemblies?

The certified Backflow Assembly Tester (BAT) is certified by the state of Washington to inspect, test, and monitor backflow prevention assemblies. (WAC 240-290-490)