Grant County, WA Noise Ordinances: Aircraft Noise (2026)

645, the Airport Safety Overlay (ASO), layers noise and height restrictions on top of the underlying zoning district for land near seven named airports: Grant County International Airport, Ephrata Municipal Airport, Grand Coulee Dam Airport, Quincy Municipal Airport, Desert Aire Airport, Warden Municipal Airport, and Moses Lake Municipal Airport. The ASO boundaries follow the FAA's Part 77 Airport Imaginary Surfaces and each airport's Runway Protection Zones, as mapped in that airport's master plan. An allowed-outright use inside the ASO can proceed without a separate application only if the Administrative Official can confirm it will not exceed 35 feet, will not penetrate the FAR Part 77 approach or transitional surfaces, sits outside a mapped Runway Protection Zone, and is not within an identified future 65 Ldn (Interior Day-Night Average Sound Level) aircraft noise impacted area shown on an airport master plan or FAA-approved layout plan.

Anything that fails one of those tests, along with every discretionary or conditional use in the ASO, needs a separate application that includes a technical noise attenuation analysis: an acoustical engineer must show the construction meets prescribed interior noise level requirements, and if windows must stay closed to hit that target, the design has to specify how the building will still be ventilated and cooled. Applicants also need statements from the airport manager, the Washington State Department of Transportation Aviation Division, and the FAA on how the use affects airport operations and safety.

Existing uses in place before the ASO was adopted are grandfathered and do not have to change to comply, so long as they do not become more nonconforming.