Backflow Laws: Washington
Washington State Backflow Prevention Laws, Regulations, and Compliance Requirements
Washington State has one of the most detailed and codified backflow prevention frameworks in the nation. WAC 246-290-490 establishes comprehensive cross-connection control program requirements for all public water systems, administered by the Washington State Department of Health (DOH). DOH issues two distinct certifications: Backflow Assembly Tester (BAT) and Cross-Connection Control Specialist (CCS). Annual testing is mandatory statewide. DOH-approved assemblies are those on the USC-FCCCHR list. Seattle Public Utilities, Tacoma Public Utilities, and other major utilities use SPU's field test report form and WAC 246-292-036 requirements. SwiftComply is widely used for test report submission. This guide covers Washington's full regulatory framework and major utility programs.
Washington State Regulatory Framework
Washington’s cross-connection control requirements are established in Washington Administrative Code (WAC) 246-290-490 — Cross-Connection Control, administered by the Washington State Department of Health (DOH), Office of Drinking Water. Washington holds EPA primacy under the federal Safe Drinking Water Act. WAC 246-290-490 is one of the most detailed state CCC regulations in the nation, covering program elements, hazard assessment, premises isolation requirements, backflow preventer approval, testing and maintenance, and records.
WAC 246-290-490 requires every public water system to: (1) Include a written description of its cross-connection control program in the water system plan; (2) Ensure cross-connections are eliminated or controlled by approved backflow preventers commensurate with hazard; (3) Conduct initial hazard evaluations and periodic reevaluations of consumer premises; (4) Take corrective action including water service denial or discontinuance for non-compliance; and (5) Notify the authority having jurisdiction before denying or discontinuing service (except in emergencies).
Approved backflow prevention assemblies: Washington defines these as RPBA, RPDA, DCVA, DCDA, PVBA, or SVBA models approved by DOH. Assemblies that appear on the USC-FCCCHR approved list are considered approved by DOH. Annual testing is required under WAC 246-290-490(7)(b) and WAC 51-56-0603.4.2 for all backflow assemblies after installation, reinstallation, relocation, or repair.
Washington DOH — Two Certifications: BAT and CCS
Washington DOH administers two separate certifications under chapter 246-292 WAC:
Backflow Assembly Tester (BAT): An individual certified under WAC 246-292 to inspect, field test, maintain, and repair backflow prevention assemblies, devices, and air gaps that protect the public water system. BAT certification is required for all backflow assembly testing in Washington. BAT certification and licensing requirements for each backflow assembly scenario are detailed in DOH Publication 331-680 (Backflow Assembly Testing Requirements).
Cross-Connection Control Specialist (CCS): An individual certified under chapter 246-292 WAC to develop and implement a cross-connection control program for a water system. Water purveyors are required to employ or contract with a CCS for their program administration.
Test Report Requirements — WAC 246-292-036
Backflow assembly testers in Washington must submit field test reports that comply with WAC 246-292-036 (field test report content requirements). DOH has developed a Sample Backflow Preventer Inspection and Field Test Report to complement the rule. Reports must contain all information required by WAC 246-292-036. Individual utilities may have their own forms that comply with the WAC standard. Seattle Public Utilities uses SPU’s Backflow Preventer Inspection and Field Test Report form. Test reports are commonly submitted electronically — many Washington utilities use SwiftComply as the test report management platform.
Washington's Cross-Connection Control Summary Report Requirement
Under WAC 246-290-490, water purveyors must submit a cross-connection control summary report (defined in WAC 246-290-010(61)) documenting the status of their cross-connection control program. This annual report to DOH covers survey activities, testing compliance, enforcement actions, and program administration. Washington’s annual reporting requirement places it in the high-regulation tier nationally — similar to Michigan’s EGLE annual report requirement and Massachusetts’s MassDEP sanitary survey system.
Major Water Purveyors in Washington
Seattle Public Utilities (SPU)
Seattle Public Utilities serves approximately 1.4 million people directly and through wholesale agreements across the greater Seattle metro area. SPU’s backflow assembly testing program requires all assemblies to be tested by a State of Washington Certified Backflow Assembly Tester (BAT). Test reports must comply with WAC 246-292-036 and be submitted using SPU’s Backflow Preventer Inspection and Field Test Report form. Submit reports and certification documents to SPU_Backflow@Seattle.gov or (206) 684-3536. Annual testing is required.
Tacoma Public Utilities — Water Division
Tacoma Public Utilities Water Division serves the Tacoma area and wholesale customers across Pierce County. Annual testing by Washington DOH-certified BATs is required. Tacoma’s water system is notable as one of Washington’s major utilities with its own cross-connection control specialist and active CCC program. WSC customers are required to have assemblies tested annually by a state-certified tester.
Puget Sound Energy — Washington Water
Washington Water (subsidiary of Puget Sound Energy) serves portions of the Puget Sound region. Annual testing by state-certified testers is required under WAC 246-290-490. Test reports are submitted to Washington Water per their filing procedures.
Spokane Public Works and Utilities
Spokane’s water system serves eastern Washington’s largest city. Annual testing by Washington DOH-certified BATs is required. Spokane has an active cross-connection control program aligned with WAC 246-290-490.
Everett Water Division
Everett’s water system serves the Snohomish County seat and surrounding communities. Annual testing is required. Everett uses SwiftComply or similar electronic platforms for test report submission.
Water Districts and Smaller Systems
Washington has hundreds of Group A public water systems (15+ service connections or 25+ people for 60+ days/year) each required to have a written cross-connection control program under WAC 246-290-490. The DOH provides a CCC Guidance Manual for Small Water Systems (Publication 331-234) to help smaller utilities implement compliant programs.
SwiftComply Adoption Across Washington
Multiple Washington water utilities have adopted SwiftComply (a cloud-based backflow assembly compliance platform) for test report management. BATs testing in Washington should check whether the specific utility they are working in uses SwiftComply or another platform (such as Aqua Backflow, The Compliance Engine, or direct email/portal submission) and register with that platform before submitting test reports.
Property Owner Compliance Summary for Washington
Washington DOH BAT: All testing must be by Washington State-certified Backflow Assembly Tester (BAT) under chapter 246-292 WAC.
Annual testing: Required under WAC 246-290-490(7)(b) and WAC 51-56-0603.4.2.
WAC 246-292-036 reports: Test reports must contain all required fields per WAC 246-292-036.
Platform: Confirm whether your utility uses SwiftComply, SPU’s form/email, or another platform before scheduling.
Assemblies: USC-FCCCHR approved assemblies required.
Find a Certified Backflow Tester in Washington
Find Washington DOH-certified BATs at getyourbackflowtested.com/backflow-testing-near-me/washington-backflow-testing or through the DOH BAT certification list — covering Seattle, Tacoma, Spokane, Everett, Bellevue, Redmond, and all major Washington communities.
Washington Regulatory Reference Links
| Resource / Agency | URL / Link Target |
|---|---|
WA DOH — Cross-Connection Control and Backflow Prevention | |
WAC 246-290-490 — Cross-Connection Control (full text) | |
WAC 246-292 — BAT and CCS Certification Requirements | |
DOH Publication 331-680 — Backflow Assembly Testing Requirements | |
DOH — CCC Rules 331-355 | |
Seattle Public Utilities — Backflow Assembly Testing | |
Washington Water (WWSC) — Cross-Connection Control |