King County, WA Parking Rules: Driveway Rules (2026)

Driveway construction and maintenance in unincorporated King County are governed by the King County Road Standards (adopted under KCC 14.42) and zoning code Title 21A. New driveways accessing a county road require a driveway permit from the Road Services Division, which reviews location for sight distance, drainage, and conflict with utilities. Residential driveways are generally required to be a minimum of 10 feet wide and a maximum of 20 feet wide at the right-of-way, though commercial and shared driveways have different standards. Surfacing requirements depend on zoning: in urban-zoned unincorporated areas, driveways must be paved with asphalt, concrete, or approved pervious surfaces; in rural zones, gravel may be allowed. Driveway slopes cannot exceed 15 percent within the first 20 feet from the road edge to prevent vehicles bottoming out and to allow safe ingress and egress. King County requires driveway culverts sized per the drainage standards where ditches exist, and property owners are responsible for maintaining culverts on their driveways. Illegal driveway connections, driveways that cause drainage problems onto neighboring properties, or driveways that block sight lines at intersections are common code enforcement issues. Driveways in Critical Areas (KCC 21A.24) or Shoreline Jurisdiction require additional review.