Seattle, WA
Backflow testing in Seattle
Updated · Editorial team; not yet technically reviewed
Short answer
Seattle Public Utilities requires backflow assemblies to be tested every year, by the anniversary of the previous year's test, by a Washington State-certified Backflow Assembly Tester who submits the results to SPU. Missing a test can bring non-compliance charges and, ultimately, water shutoff.
What's different in Seattle
After installation and initial testing, Seattle customers must have backflow preventers tested every year. [1]
Tests must be done by a Washington State-certified Backflow Assembly Tester (BAT), with results submitted to Seattle Public Utilities, by the anniversary date of the previous year's test. [1]
SPU sends reminders, but it's the water service owner's responsibility to test on time; SPU may assess non-compliance charges and possibly terminate water service if testing isn't done. [1]
SPU's backflow program can be reached at [email protected] or (206) 684-3536. [1]
Your deadline is your anniversary date
Seattle doesn't use one citywide deadline. Each assembly is due by the anniversary of its last test, so if you tested late last year, your deadline moved too. Putting the date on your calendar, or booking the same month every year, avoids non-compliance charges.
Staying compliant
Find your due date
Check last year's report or SPU's reminder for the anniversary date.
Hire a Washington-certified BAT
Only a state-certified Backflow Assembly Tester's results are accepted.
Confirm the report was filed
The tester submits results to SPU; ask for a copy.
Repair and retest if it fails
A failed assembly isn't compliant until it passes.
Seattle irrigation and seasonal systems
Many Seattle sprinkler systems sit idle through the wet season, but the annual test still follows the anniversary date, not the irrigation season. Drain assemblies before hard freezes, which do occur in Seattle. For what a backflow preventer does, the device types and how a test works anywhere, see backflow testing.
Further reading: How backflow happens and which devices homes use.
Common questions
When is my Seattle backflow test due?
By the anniversary date of last year's test. Each assembly has its own date.
Who can test a backflow assembly in Seattle?
A Washington State-certified Backflow Assembly Tester (BAT), who submits the results to SPU.
What if I miss my Seattle backflow test?
SPU may assess non-compliance charges and can terminate water service if testing isn't completed.
Does SPU remind me about backflow testing?
SPU sends reminders, but meeting the deadline is the water service owner's responsibility.
How do I contact SPU's backflow program?
Email [email protected] or call (206) 684-3536.
Does my Seattle sprinkler need testing if I don't use it in winter?
Yes. The annual test follows your anniversary date regardless of when the system runs.
Do I get a new deadline if I test late?
The anniversary is based on the previous year's test, so test on time to avoid charges.
Can my landscaper test my Seattle backflow device?
Only if they're a Washington State-certified Backflow Assembly Tester.
Should I drain my backflow assembly in a Seattle winter?
Yes, before hard freezes, to avoid cracked bodies and failed tests.
Who fixes a failed backflow assembly in Seattle?
A certified tester or licensed plumber; then it must pass a retest.
More plumbing help in Seattle
- Sewer Line Repair in SeattleSeattle side sewer rules: owners maintain the entire side sewer, when you need an SDCI permit, emergency repair rules, typical permit fees, and shared lines.
- Water Line Repair in SeattleSeattle water lines: owners install and maintain the private line from the city union to the house, and how SPU's leak adjustments treat city-side and.
- Sewer Backup in SeattleSeattle sewer backups: most backup calls trace to the privately owned side sewer, when SPU claims apply, and the backwater valves that protect basements.
- Toilet Installation in SeattleSeattle toilet replacement: the Saving Water Partnership's $100 rebate for replacing pre-2004 toilets, free toilets for income-qualified homeowners.
- Drain backing up in SeattleWhy Seattle drains back up: grease causes about a third of the city's sewer backups, the foods it comes from, safe checks, and when it's the side sewer instead.
- Backflow Testing: the full guideWhat backflow is, which homes and businesses need backflow preventers, how annual backflow testing works, and what happens if a device fails.
- Plumbing in SeattleLocal water, housing and climate conditions, and the calls Seattle homes need most.
How other cities handle it
- Backflow testing in AustinAustin Water's backflow testing rules: who may test, the 5-day report deadline, online filing, and the irrigation rebates that pair with an upgrade.
- Backflow testing in San AntonioSAWS backflow testing rules for San Antonio: the June 30 annual deadline, the codes behind it, reminder notices, and what a 10-day notice means.
- Backflow testing in DenverDenver Water's backflow rules: annual testing, the May–September irrigation testing season, required device types, 30-day reminders, and where results go.
- Backflow testing in PortlandPortland Water Bureau backflow rules: yearly testing by a state-certified tester, the spring timing it prefers, reminder letters with labels, and shutoff risk.
- Backflow testing in CharlotteCharlotte Water backflow rules: residential irrigation tested every 3 years, residential domestic yearly, approved testers, and RP assemblies on irrigation.
- Backflow testing in RaleighRaleigh Public Utilities backflow rules: residential irrigation tested by July 1 every three years, commercial yearly, owner-paid certified testing, and contacts.
- Backflow testing in TampaCity of Tampa Water Department backflow rules: residential tests every two years, commercial yearly, certified technicians, and the 7-day online reporting rule.
- Backflow testing in Salt Lake CitySalt Lake City Public Utilities backflow rules: tests within 10 days of installation and yearly after, which homes need protection, and secondary water.
- Backflow testing in Colorado SpringsColorado Springs Utilities backflow rules: who must test annually, the July 1 deadline, the $405 fine, licensed testers entering results, and single-family guidance.
- Backflow testing in Fort WorthFort Worth backflow rules: annual tests for commercial and health-hazard assemblies, a three-year cycle for low-hazard irrigation, and registered testers.
- Backflow testing for JEA customers in JacksonvilleJEA residential backflow rules: testing at least every two years by JEA Qualified Vendors, dual checks replaced every five years, and reclaimed-water irrigation.
- Backflow testing in Fort LauderdaleFort Lauderdale backflow rules: residential irrigation tested every two years, commercial yearly, only PVB or RP devices on irrigation meters, and certified testers.
- Backflow testing in DallasDallas backflow rules: lawn irrigation assemblies don't need annual tests, only when new, repaired or replaced; high-hazard assemblies need annual registered tests.
- Backflow testing in HoustonHouston backflow testing: testing companies must register with the city, testers need TCEQ licenses, and gauges need annual calibration reports filed with Houston.
- Backflow testing in PhoenixPhoenix backflow rules: assemblies tested at least yearly, 60 days to test after the reminder letter, then a 72-hour disconnection notice. Who needs one at home.
- Backflow testing in PhiladelphiaPWD backflow rules: test at installation, after any repair and yearly by a City-certified technician, file Form 79-770 within 48 hours.
Sources (1)
- Seattle Public Utilities, Backflow Assembly Testing · checked 2026-10-03