Seattle, WA Fence Regulations: Permit Requirements (2026)

King County Code (KCC) Title 16 (Building and Construction Standards) adopts the Washington State Building Code (IBC/IRC) administered by the King County Department of Local Services, Permitting Division (206-296-6600). A building permit is required for any fence more than 6 feet in height above grade, measured from the lowest adjacent grade. Retaining walls over 4 feet from the bottom of the footing to the top of the wall, or any retaining wall supporting a surcharge (such as a driveway, swimming pool, or structure), also require a permit. Fences located within Critical Areas regulated by KCC Title 21A.24 (wetlands, fish and wildlife habitat conservation areas, steep slopes, landslide hazard areas, and shorelines) may require additional review even when under 6 feet, because they can interrupt wildlife corridors and salmon habitat. Waterfront and shoreline fences within 200 feet of a salmon-bearing stream or marine shoreline are subject to the Shoreline Master Program and may require a Shoreline Exemption. Permit fees are based on valuation, and applications require a site plan, property lines or a survey, and elevation drawings.