Portland, ME Environmental Rules: Boat Dock Permits (2026)

Article 11 of the Land Use Code, the Shoreland Overlay Zone, governs all piers, docks, wharves, bridges and shoreline stabilization within 250 feet of the normal high-water line of a river or the upland edge of a wetland. 2 defines a temporary structure as one in or over the water less than seven months in any 12-month period, and a permanent one as seven months or more. No more than one pier, dock, wharf or similar structure below the normal high-water line is allowed on a single lot, except in the Working Commercial, Eastern Waterfront and Western Waterfront zones.

On non-tidal waters, a new permanent pier or dock is barred unless the applicant proves a temporary structure is not feasible and has already obtained a Maine DEP permit under the Natural Resources Protection Act. § 480-C, and may also need Army Corps of Engineers or Board of Harbor Commissioners approval if it sits in navigable waters. New buildings placed on, over or abutting a pier, wharf or dock cannot exceed 20 feet in height above that structure, cannot be converted to residential dwelling units in any zone, and a structure built on a float is prohibited unless it is registered with the Maine Department of Inland Fisheries and Wildlife as a watercraft.

Every applicant for a site plan or building permit in the Shoreland Overlay Zone must submit a written application with a scaled boundary-survey plan to the Building Authority, plus preconstruction and postconstruction shoreline photographs within 20 days of completion.