Shoreline, WA Environmental Rules: Boat Dock Permits (2026)

Shoreline Municipal Code § 20.230.170 governs piers and docks within shoreline jurisdiction. A proposal is allowed only when it satisfies conditions A through K: the public's need for the structure must be clearly demonstrated consistent with the public trust doctrine, avoidance of impacts to critical saltwater habitat by an alternate location must be infeasible, and the project must result in no net loss of ecological function. Private, noncommercial joint or community docks may be authorized only if the same no-net-loss and infeasibility findings are met, and applicants must show mooring buoys are not a feasible alternative before shared dock moorage is approved.

Materials for submerged piles, floats, or decking must be concrete or steel per WDFW and U.S. Army Corps of Engineers best management practices; treatment with herbicides, fungicides, paint, or pentachlorophenol is barred, and arsenate compounds or creosote are prohibited outright. Pilings must clear a minimum of two feet above extreme high tide and a maximum of five feet above the ordinary high-water mark, and floats cannot rest on the substrate. To limit shading of nearshore habitat, docks, piers, floats, and lifts cannot exceed six feet in width, and shared docks serving two lots are capped at 700 square feet, rising to 1,000 square feet for three or more lots.

All new piers and docks must be fully grated, with at least 40 percent open decking so that 60 percent ambient light reaches the water beneath the structure. Repair or replacement rules in the adjoining § 20.230.175 require that any repair touching 50 percent or more of an existing deck upgrade the entire structure to the same grating standard, and expansion of existing over-water structures is flatly prohibited.