King County, WA Landscaping Rules: Grass Height Limits (2026)

King County Code does not impose a maximum grass height such as the 8-inch or 12-inch limits common in California or Arizona municipalities. In the Puget Sound wet marine climate, maintained lawns are a preference, not a legal requirement. Tall grass is only a code issue when it rises to a public nuisance under KCC Title 12 or 21A, harbors rodents subject to Public Health Seattle and King County rules, or creates an imminent fire hazard near occupied structures (addressed through the Fire Marshal). Rural Area (RA), Resource (F, A), and large unincorporated parcels are expressly expected to contain meadows, pasture, and natural vegetation consistent with the Growth Management Act and the 2016-2040 Comprehensive Plan. Noxious weeds designated on the King County Noxious Weed Control Board list (such as tansy ragwort, knotweed, and Scotch broom) must be controlled under RCW 17.10 and local noxious weed rules. Residents in denser Urban (UR, R) zones may hear from Code Enforcement if overgrowth produces complaints, but enforcement is complaint-driven rather than proactive mowing inspections.