Yes, if your sprinkler system connects to a public water supply. Washington requires the backflow prevention assembly to be tested at least once every 12 months by a state-certified Backflow Assembly Tester, with results filed with your water purveyor. A residential test in the Spokane area typically runs $60 to $120 per assembly as of 2026.
Skipping the test can lead to notices from your purveyor and, eventually, water service issues. Spring startup is a natural time to schedule it.
More: Backflow testing for Spokane sprinkler systems.
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