Backflow Testing Moses Lake WA

Certified Backflow Assembly Testing in Moses Lake, WA

Clean, potable drinking water is essential for public health. To prevent non-potable contaminants—such as lawn fertilizers, weed killers, stagnant irrigation water, and industrial chemicals—from being siphoned back into the public water supply, plumbing regulations require approved backflow prevention assemblies at all cross-connection hazard points.

In Moses Lake, where residential underground sprinkler systems are ubiquitous due to dry summer weather and agricultural industries operate across Grant County, backflow assemblies must be inspected and certified annually by a state-certified Backflow Assembly Tester (BAT). Washington Plumbing provides prompt, thorough testing, on-site repairs, and automated reporting to City of Moses Lake water purveyors. Call our team at (253) 201-3775 to schedule your test.

Why Annual Backflow Testing Is Mandatory

Backflow occurs through two hydraulic phenomena: backsiphonage (caused by a sudden drop in municipal main pressure, such as from a nearby fire hydrant opening or a ruptured water line) and backpressure (when private equipment generates higher pressure than the supply line).

Backflow prevention assemblies rely on internal springs, rubber disc seals, and check valves that are constantly under water pressure. Over time, Moses Lake's mineral-laden hard water creates scale deposits on valve seats, while grit and thermal stress fatigue the internal springs. Without regular testing, an assembly can fail silently, exposing your family and neighbors to hazardous contaminants. Under Washington Administrative Code (WAC 246-290-490), annual certification is a legal requirement.

Types of Backflow Devices We Test and Service

Our licensed technicians are certified to test, repair, and install all commercial and residential backflow assemblies approved in Washington:

• Double Check Valve Assemblies (DCVA): Most common on residential underground lawn sprinkler systems and fire sprinkler lines, featuring two independently acting internal check valves.
• Reduced Pressure Backflow Assemblies (RPBA / RPZ): Required for high-hazard commercial applications, car washes, boiler feeds, and chemical injection systems, featuring a hydraulic relief valve between two checks that dumps water if either fails.
• Pressure Vacuum Breakers (PVB): Installed on elevated irrigation supply lines to protect against backsiphonage conditions.

What Happens During a Certified Backflow Inspection?

When our certified tester arrives at your property, we conduct a standardized diagnostic protocol:

1. We connect calibrated differential pressure gauges to the assembly's precision test cocks.
2. We isolate the assembly and measure the exact opening and closing pressure of each internal check valve, verifying they hold minimum required PSI differentials.
3. For RPBA devices, we verify that the differential relief valve opens reliably before backpressure can force water through the upstream check.
4. If the device passes, we affix a certified inspection tag to the unit and submit the official compliance paperwork directly to the City of Moses Lake Water Department or Grant County water purveyor.
5. If an assembly fails due to mineral scale, debris, or a worn rubber seal, our trucks carry rebuild kits to restore compliance during the same visit.

Serving Moses Lake and Grant County Communities

We test residential irrigation and commercial backflow assemblies across all Moses Lake neighborhoods, including Peninsula waterfront properties, Downtown Moses Lake commercial centers, Knolls Vista, and industrial facilities near Grant County International Airport and along the I-90 corridor. We also serve neighboring agricultural and residential centers like Ephrata, Warden, and Othello detailed in our Service Areas directory. In cases of sudden backflow device ruptures or freezes, call our emergency plumbing team right away.

Backflow Testing FAQ