Homeowners across the Tri-Cities are used to thinking about sprinkler shutoff this time of year — when to blow out the lines, when the irrigation district turns off the water. There's a separate, easy-to-miss requirement tied to that same system: an annual backflow preventer test, required by state law, that has nothing to do with winterizing your lawn and everything to do with keeping lawn water out of your drinking water.
Skip it, and the penalty isn't a frozen pipe. In West Richland, it's your household water getting shut off.
Why cities require this
Any home with an irrigation system tied to city water has a backflow prevention assembly somewhere near the meter or hose bib. Its job is to stop water from siphoning backward — out of a sprinkler line, a chemical injector or a pool — into the pipes that supply drinking water. The requirement comes from Washington Administrative Code 246-290-490, and Kennewick, Pasco and West Richland all run local cross-connection control programs built on that state rule, according to each city's own program pages (West Richland).
Kennewick's program isn't an abstraction. The city says it dates to 1978, when an unprotected cross connection between city water and irrigation water was suspected of causing several people to be hospitalized, according to the city's Cross Connection page. Kennewick now monitors more than 1,800 backflow prevention assemblies citywide under Kennewick Municipal Code 15.41, per the city's Backflow Incidents page.
What's required, city by city
Kennewick. The city says water customers are responsible for making sure their backflow devices are operated, maintained and tested under its Cross Connection Control Regulations. For pressure vacuum breaker assemblies — the common type on residential irrigation lines supplied by city water — state rules require annual testing by a state-certified tester, according to Kennewick's PVBA page. The city posts an official test report form and a list of certified testers residents can hire.
Pasco. The city runs a comparable Cross Connection program, citing federal law and state regulation to protect the domestic water supply from contamination, most often when domestic water is used for yard irrigation, according to the city's water protection page. Residents with questions can call Pasco's Cross Connection line at (509) 545-3464.
West Richland. This city spells out the consequences most clearly. Backflow assemblies are required on any irrigation system connected to city water, and those assemblies must be tested annually. The city's Cross Connection Specialist, Brandon Dawkins, sends a reminder letter 30 days before each property's test is due, according to the city's FAQ. Miss the deadline, and the city says it may terminate water service entirely until the test is completed and results are turned in — not just irrigation water, but the whole connection. Residents with questions can reach Dawkins at 509-967-5434. The city also keeps an updated list of certified backflow testers, current as of Aug. 31, 2026, including Backflow Tri-Cities (509-940-7746) and Piche Backflow Testing (509-539-1703).
West Richland has one additional wrinkle worth knowing about. Properties tied into both city water and an irrigation district — Kennewick Irrigation District or Columbia Irrigation District — need a Reduced Pressure Backflow Assembly instead of the simpler device, and it has to be inspected by the city's Cross Connection Specialist before a certified tester signs off, according to the city's cross-connection FAQ. If your lot backs up to a KID or CID lateral and also has city water, that's the category to check.
Richland. The city almost certainly runs an equivalent program under the same state rule, but Richland's specific deadline language, contact number and enforcement policy weren't available in city documents checked for this story. Homeowners there should call Richland Public Works directly to confirm their test schedule rather than assume Kennewick's or West Richland's timeline applies.
How this fits with your fall sprinkler shutoff
The backflow test is a separate requirement from turning off your irrigation water for winter, which Tri-Cities Today has covered by provider. You can have your system blown out and winterized and still be out of compliance on the annual backflow test, because the test checks the device itself, not whether water is flowing through it this week.
Quick checklist
- Find your backflow assembly's test due date — check for a postcard or letter from your city, or call the numbers above.
- Confirm which assembly type you have: a standard pressure vacuum breaker, or a Reduced Pressure Backflow Assembly if you're also on an irrigation district.
- Hire a certified tester from your city's list, not just any plumber.
- Submit the test report to your city before the deadline. In West Richland, missing it can mean your water gets shut off, not just your sprinklers.
- If you winterize before testing, make sure the tester can still access the assembly.
Frequently asked questions
Do I need a backflow test if my irrigation runs off a well, not city water? No. Kennewick's rule specifically applies to pressure vacuum breaker assemblies on irrigation systems supplied by city water, per the city's PVBA page. Wells and irrigation-district-only connections fall outside that particular city requirement, though irrigation districts may have their own rules.
What happens if I skip the test? In West Richland, the city says it may terminate water service until the test is done and the results are submitted, according to its FAQ. Kennewick and Pasco both frame testing as a customer responsibility under their cross-connection ordinances, though exact penalty language for those two cities wasn't detailed in the pages reviewed for this story.
Can I test the backflow assembly myself? No. All three cities require testing by a state-certified backflow tester, not the homeowner. Each city maintains its own list of certified testers residents can hire — Kennewick's is here, West Richland's updated list is here.
I'm on both city water and an irrigation district. Does that change anything? Yes, at least in West Richland. Properties connected to both city water and Kennewick Irrigation District or Columbia Irrigation District need a Reduced Pressure Backflow Assembly, which the city's Cross Connection Specialist must inspect before a certified tester can sign off, according to the city's FAQ.
