10 licensed plumbers

Backflow Testing & Annual Certification in Seattle

Every plumber listed offers backflow testing and is verified active with the Washington State Department of Labor & Industries.

About this service

Typical cost
$65 - $100

Professional backflow testing in Seattle certifies that your backflow preventer assembly works correctly. A backflow preventer is a mechanical assembly installed on water lines to prevent non-potable water, chemicals, or sewage from siphoning backward into the public drinking water supply. Annual testing is required by law. Standard residential backflow testing in Seattle ranges from $65 to $80, while testing in deep vaults or hard-to-access locations costs $100.

Primary Cause of Failure

  • •Wear and tear of internal check valves, springs, or rubber seals over time

If neglected

The public water supply can become contaminated with chemical fertilizers, stagnant water, or pathogens.

Probability of a DIY fix for Backflow Prevention Testing and Certification?

Zero. Washington State law mandates that backflow assemblies must be inspected and certified annually by a Department of Health (DOH) certified Backflow Assembly Tester (BAT). DIY testing is strictly prohibited.

Insurance coverage

Insurance does not cover annual testing fees, but a failure to perform annual testing can result in the local water utility shutting off water service.

Licensed plumbers offering backflow testing