City water utility · Washington
Backflow testing in Seattle, WA
Seattle Public Utilities's rules: who must test, when it's due, testers, filing and penalties.
Seattle requires a yearly test of every installed backflow assembly (sprinklers, fire lines, businesses, some homes) by a state-certified tester, who files the report online at no charge. Skipped tests bring fees and possible water shutoff.
- Who
- Lawn sprinkler systems: every year
- Fire sprinkler lines: every year
- Businesses: every year (some)
- Homes (other than sprinklers): every year (some)
- Due
- Test every year.
- Testers
- Hire a tester certified by the state of Washington.
- Filing
- Your tester files online in SAMS Tester Portal. Fee: No fee.
- If late
- Water can be shut off. Reminder letter, per assembly (no proof of a passing test 30 days after the first notice): $105 each backflow preventer.
Who must have a backflow test
Every backflow assembly on a Seattle water service must be tested once a year, plus after any repair or replacement and before a new one goes into service. Which type you need depends on the hazard. High-hazard businesses need a reduced pressure assembly at the meter. Sprinkler, fire and tall-building lines can use lower-level assemblies.
- Lawn sprinkler systemsRequiredevery year
Applies to the assembly on the sprinkler line. Devices that cannot be tested follow separate rules; call SPU if yours is one.
- Fire sprinkler linesRequiredevery year
Approved flow-through fire systems are not counted as cross-connections.
- BusinessesSomeevery year
Required where SPU finds a cross-connection hazard. High-hazard sites such as hospitals, labs, car washes, laundries and food plants need a reduced pressure assembly just after the meter. Buildings over 3 stories or 30 feet can use a lower-level assembly.
- Homes (other than sprinklers)Someevery year
Only homes where SPU has required an assembly, for example for a boiler, pool or spa, pump, well or other second water source, or gray water system.
Assemblies tested: Reduced pressure assembly (RP or RPZ), Reduced pressure detector assembly (fire lines), Double check valve assembly, Double check detector assembly (fire lines), Pressure vacuum breaker, Spill-resistant vacuum breaker. What these are
Source: seattle.gov · checked Oct 18, 2026
When the test is due
Test every year. SPU sends a notice when your test is due. Send in proof of a passing test within 30 days of getting it. If SPU has no proof by then, it sends a reminder with a charge.
Notices: SPU sends a test-due notice to the water service owner. The notice has a Letter Code that your tester uses to file the report. If you never get a notice, SPU may not have your assembly on record, so call to add it.
Source: seattle.gov · checked Oct 18, 2026
Finding a tester
Hire a tester certified by the state of Washington. Pick your county on the state list, then call a few testers to compare price and timing. The tester must have a state certificate and test kit calibration papers on file with SPU before a report can be filed.
Source: seattle.gov · checked Oct 18, 2026
Filing the test report
- Who files
- Your tester
- How
- Online in SAMS Tester Portal
- Fee
- No fee
- Form
- Test report form
Since August 17, 2026, reports must be entered in the SAMS tester portal. SPU no longer takes them by email. The tester needs the Letter Code from your notice, or the assembly's exact serial number. Ask your tester to confirm the report was filed and keep a copy for your records.
Source: seattle.gov · checked Oct 18, 2026
If the test is late or fails
Seattle sends reminders, but the owner is responsible for getting the test done on time. If it is not done, SPU can charge fees and can shut off water. SPU's charge list (in effect since January 2025) shows $105 per assembly for a reminder letter, $155 for a late-test shutoff notice, and $120 each to shut off and turn the water back on. Call SPU to confirm current amounts.
- Reminder letter, per assembly (no proof of a passing test 30 days after the first notice): $105 each backflow preventer
- Late assembly test shutoff notice: $155
- Water shutoff, and turning the water back on, for a cross-connection problem (each trip): $120 each
Rule: Seattle Municipal Code § 21.04.070 (Cross-connections)
Source: seattle.gov · checked Oct 18, 2026
For testers working in Seattle
Testers must register with Seattle Public Utilities before their reports are accepted.
- Current Washington BAT certification (validation card) on file with SPU
- Test kit calibration certificate on file with SPU
- Company, each tester and each test kit registered in the SAMS tester portal
- Letter Code from the customer's notice, or the assembly's exact serial number, to file a report
- A different email address for each company if you test for more than one
Register your company in the SAMS tester portal, then add yourself as a tester and add each test kit. Upload your BAT card and your calibration certificate. Reports cannot go in until these are in the system. Reports are entered in the portal only; SPU does not charge to file them, so do not pass on a filing fee to customers.
Source: seattle.gov · checked Oct 18, 2026
The rules behind it
- Seattle Municipal Code § 21.04.070: Water service can be denied or discontinued for a customer who does not install, maintain, test or inspect required assemblies. SPU can also charge the account for its costs, including service calls.
- WAC 246-290-490: State cross-connection control rule.
- WAC 246-292-036: What a test report must contain.
Contact Seattle Public Utilities
Source: seattle.gov · checked Oct 18, 2026
Backflow testing in Seattle: questions
Do I need a backflow test for my sprinkler system in Seattle?
Yes. Seattle Public Utilities requires backflow assemblies on lawn sprinkler systems to be tested every year. Applies to the assembly on the sprinkler line. Devices that cannot be tested follow separate rules; call SPU if yours is one.
When is my backflow test due in Seattle?
Test every year. SPU sends a notice when your test is due. Send in proof of a passing test within 30 days of getting it. If SPU has no proof by then, it sends a reminder with a charge. SPU sends a test-due notice to the water service owner. The notice has a Letter Code that your tester uses to file the report. If you never get a notice, SPU may not have your assembly on record, so call to add it.
How do I find a backflow tester in Seattle?
Hire a tester certified by the state of Washington. Pick your county on the state list, then call a few testers to compare price and timing. The tester must have a state certificate and test kit calibration papers on file with SPU before a report can be filed.
Who sends the backflow test report to Seattle Public Utilities?
Your tester files the test report in SAMS Tester Portal. Filing fee: No fee. Since August 17, 2026, reports must be entered in the SAMS tester portal. SPU no longer takes them by email. The tester needs the Letter Code from your notice, or the assembly's exact serial number. Ask your tester to confirm the report was filed and keep a copy for your records.
What happens if I skip my backflow test in Seattle?
Seattle sends reminders, but the owner is responsible for getting the test done on time. If it is not done, SPU can charge fees and can shut off water. SPU's charge list (in effect since January 2025) shows $105 per assembly for a reminder letter, $155 for a late-test shutoff notice, and $120 each to shut off and turn the water back on. Call SPU to confirm current amounts.
Every fact on this page comes from Seattle Public Utilities's own pages, forms or code, checked Oct 18, 2026. Rules change: your notice and the utility have the final word. Spot a mistake? Tell us.