State guide
Backflow testing in Washington
Washington community water systems must run cross-connection control programs. Backflow assemblies that protect the public water system get tested when installed, after repairs, and every year. Testers must hold a Department of Health certificate; Washington Certification Services runs the exams.
What Washington requires
Every community water system in Washington must run a cross-connection control program. Backflow assemblies that protect the public water system must be tested by a state-certified tester when they are installed, after any repair or move, after a backflow incident, and every year after that. A water system can ask for tests more often at high-hazard sites or for assemblies that keep failing. Irrigation vacuum breakers (AVBs) are inspected, not tested. Each water system decides how test reports reach it, and a city can set stricter rules.
Run by Washington State Department of Health, Office of Drinking Water under WAC 246-290-490 (cross-connection control; testing in subsection 7), WAC 246-292-034 (duties of a backflow assembly tester), WAC 246-292-036 (what a test report must contain), DOH 331-680, Backflow Assembly Testing Requirements.
Source: app.leg.wa.gov · checked Oct 18, 2026
Who certifies testers
To test assemblies that protect a Washington water system, you need a Backflow Assembly Tester (BAT) certificate from the Department of Health. You pass a hands-on exam, then a computer exam, and renew every year. Washington Certification Services (WCS) runs the program for the state.
Source: wcs.greenriver.edu · checked Oct 18, 2026
Water utilities in Washington
Pick your water provider: it is the name on your water bill or on your test notice.
- BellevueCity of Bellevue UtilitiesSprinklers: every yearFiles in Backflow Assembly Testing PortalShut-off possibleTest every year.
- KentCity of Kent Water UtilitySprinklers: every yearShut-off possibleTest every year after the assembly is installed.
- RentonCity of Renton Water UtilitySprinklers: every yearFiles in iBackflowShut-off possibleTest every year.
- SeattleSeattle Public UtilitiesSprinklers: every yearFiles in SAMS Tester PortalShut-off possibleTest every year.
- SpokaneCity of Spokane Water and Hydroelectric ServicesSprinklers: every yearShut-off possibleTest every year.
- TacomaTacoma Water (Tacoma Public Utilities)Sprinklers: every yearShut-off possibleTest every year.
- VancouverCity of Vancouver Water Utility (Public Works, Water Quality)Sprinklers: every yearFiles in SAMSShut-off possibleTest every year.
Backflow testing in Washington: questions
Which Washington water utilities require yearly sprinkler backflow tests?
Of the 7 utilities on this site, all require a yearly test of lawn sprinkler backflow assemblies: Bellevue, Kent, Renton, Seattle, Spokane, Tacoma and Vancouver.
Who certifies backflow testers in Washington?
To test assemblies that protect a Washington water system, you need a Backflow Assembly Tester (BAT) certificate from the Department of Health. You pass a hands-on exam, then a computer exam, and renew every year. Washington Certification Services (WCS) runs the program for the state.
Can a Washington utility shut off my water for a missed backflow test?
All utilities on this site say they can: Bellevue, Kent, Renton, Seattle, Spokane, Tacoma and Vancouver. Each one sends notices first; see its page for the steps and fees.
Do fire sprinkler lines in Washington need backflow tests?
Yes, at Bellevue, Kent, Renton, Seattle, Spokane and Tacoma, every year. Check each utility's page for which fire lines are covered.