Dock, pier and float rules in Mount Desert, Maine
In the Shoreland Residential districts, a permanent pier, dock or wharf needs conditional use approval from the Mount Desert Planning Board. Only one marine structure is allowed per lot, floats are capped at 400 sq ft, and the whole pier, ramp and float can't be more than 225 ft long. A small seasonal structure under 10 ft long needs only a Code Enforcement Officer permit, though state and federal permits may still apply.
| Approval (Shoreland Residential, Residential, Rural/Woodland, Shoreland Commercial, Conservation) | Planning Board conditional use approval [1] |
| Districts where prohibited | Village Residential 1-2, Village Commercial, Resource Protection, Stream Protection [1] |
| Small seasonal structure (under 10 ft, in the water under 7 months a year) | CEO permit only; state and federal permits may still be needed [2] |
| Seasonal vs permanent | Permanent = in or over the water 7 months or more in any 12 [3] |
| Max length of pier, ramp and float combined | 225 ft (or the length needed to reach 6 ft of water at mean lower low water, if less) [6] |
| Max length of permanent parts | 150 ft [6] |
| Max width of pier walkway or ramp | 6 ft [6] |
| Max float area (single owner) | 400 sq ft [6] |
| Shallow tidal flats | No permanent structure seaward of the upland edge of the coastal wetland where high water to mean lower low water is more than 160 ft [9] |
| Number per lot | 1 marine structure [7] |
| Temporary non-commercial dock width | 6 ft max [4] |
Who approves it
The use table lists permanent piers, docks, wharves and other structures over or below the normal high-water line as needing Planning Board conditional use approval in the Residential, Shoreland Residential, Rural/Woodland, Shoreland Commercial and Conservation districts [1]. They're prohibited in Village Residential 1 and 2, Village Commercial, Resource Protection and Stream Protection. In Village Residential 3 they're allowed only with a hotel or motel. Marine structures under 10 ft long that are in the water less than 7 months a year need only a CEO permit, though state and federal permits may still be needed [2].
Seasonal vs permanent
A structure is temporary if it stays in or over the water less than 7 months in any 12-month period, and permanent if it stays 7 months or more [3]. A temporary non-commercial pier or dock can't be wider than 6 ft [4]. On non-tidal waters (ponds and lakes), a new permanent pier needs proof to the Planning Board that a temporary one isn't feasible, plus a Maine DEP permit [5].
Size limits
The structure must be no larger than needed and can't span more than one-third of the width of the water body. Specific limits [6]:
- 225 ft total for pier, ramp and float, or the length needed to reach 6 ft of water at mean lower low water, if less
- 150 ft for permanent parts, 75 ft for ramp and float
- 6 ft maximum width for pier walkway and ramp
- 400 sq ft of floats (800 for two owners sharing, 1,200 for three or more)
Where the flats are wide (more than 160 ft from the high-water line to mean lower low water), no permanent pier is allowed past the upland edge of the coastal wetland, so you'd be limited to a ramp and float [9]. Outside Shoreland Commercial, structures on a pier can't be taller than 20 ft above the deck [10].
Only one marine structure is allowed per lot [7]. Structures on a pier are limited to those that need water access, and existing ones can't be turned into homes. The Planning Board or CEO may require an environmental impact assessment.
Harbor rules
The Harbor Ordinance's mooring rules say all floats (commercial and private) and lobster cars must be registered with the Harbor Master and have a mooring on each end [8]. That rule appears aimed at moored floats; ask the Harbor Master whether a float attached to your pier must also be registered. In a designated mooring area, the Planning Board asks the Harbor Master for comments.
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Next steps
- Confirm your district and whether the structure will be seasonal (under 7 months a year) or permanent.
- Prepare plans showing pier, ramp and float dimensions, water depth at mean lower low water and distance to neighboring structures.
- Apply to the Mount Desert Planning Board through Code Enforcement / Planning (207-276-5731) for conditional use approval, or for a CEO permit if it's a small seasonal structure under 10 ft.
- Apply for state and federal permits (Maine DEP and U.S. Army Corps of Engineers) and register any moored float with the Harbor Master.
Common questions
- Do I need a permit to build a dock in Mount Desert, Maine?
- Usually. A permanent pier, dock or wharf needs Planning Board conditional use approval in the Residential, Shoreland Residential, Rural/Woodland, Shoreland Commercial and Conservation districts. State and federal permits may still apply.
- Can I put a small seasonal dock in without Planning Board approval in Mount Desert, Maine?
- A marine structure under 10 ft long that is in the water less than 7 months a year needs only a Code Enforcement Officer permit. State and federal permits may still be needed.
- How long can a dock be in Mount Desert, Maine?
- Pier, ramp and float together can be at most 225 ft, or the length needed to reach 6 ft of water at mean lower low water, if less. Permanent parts are capped at 150 ft, and walkways and ramps at 6 ft wide.
- How many docks can I have per lot in Mount Desert, Maine?
- One marine structure per lot. Floats are capped at 400 sq ft for a single owner.
State and federal rules for docks and piers
DEP permit (Natural Resources Protection Act): Building, repairing or altering a permanent structure in, on or over a great pond, river, stream or coastal wetland needs a DEP permit. "Permanent" means the structure stays in place more than 7 months in any 12-month period. A seasonal dock that comes out each year generally isn't a permanent structure.
State shoreland minimums (your town's ordinance applies these):
- Only one pier, dock or wharf per lot, unless the lot has at least twice the minimum shore frontage.
- A temporary, non-commercial dock on fresh water can be no wider than 6 ft.
- A new permanent dock on fresh water is allowed only if a temporary dock isn't feasible and DEP has issued a permit.
- No living space on or attached to a dock.
State-owned bottom: Below the low-water mark in tidal waters and in great ponds, the bottom belongs to the state. Permanent structures of any size, and large temporary ones, need a lease or easement from the Bureau of Parks and Lands. Non-permanent structures under 500 sq ft don't need one.
Federal and harbor rules: In tidal waters, docks and floats also need U.S. Army Corps of Engineers approval. Moorings are handled by your town's harbormaster under local ordinance (38 M.R.S. §7).
What the ordinance says
- Sec. 3.4, Permitted, Conditional, and Excluded Uses by District (table), Land Use Zoning Ordinance, p. 19
Extending over or X C C C X C C X X C12 below the Normal
- Sec. 3.4, table footnote 13, Land Use Zoning Ordinance, p. 20
Marine structures that are less than 10 feet in length and which remain in or over the water for less than seven (7) months in any period of twelve (12) consecutive months only require a permit from the Code Enforcement Officer (state and federal permits may still be needed).
- Sec. 8, Definitions: Piers, Docks, Wharves, Land Use Zoning Ordinance, p. 117
Temporary: Structures which remain in or over the water for less than seven (7) months in any period of twelve (12) consecutive months. Permanent: Structures which remain in or over the water for seven (7) months or more in any period of twelve (12) consecutive months.
- Sec. 6C.7.4, Size, Land Use Zoning Ordinance, p. 87
A temporary pier, dock or wharf shall not be wider than six feet for non-commercial uses.
- Sec. 6C.7.6, New permanent piers and docks, Land Use Zoning Ordinance, p. 87
New permanent piers and docks on non-tidal waters shall not be permitted unless it is clearly demonstrated to the Planning Board that a temporary pier or dock is not feasible, and a permit has been obtained from the Department of Environmental Protection, pursuant to the Natural Resources Protection Act.
- Sec. 6C.7.12, Dimensional limits, Land Use Zoning Ordinance, p. 88
Maximum length of entire marine structure (i.e., pier, ramp and float combined) 225 feet 1 Maximum length of all permanent structures 150 feet Maximum length of all non-permanent structures (i.e., ramp and float) 75 feet 2 Maximum width of pier walkway 6 feet Maximum width of ramp 6 feet Maximum square footage of floats 400 square feet
- Sec. 6C.7.14, Limit on number, Land Use Zoning Ordinance, p. 88
There shall be no more than one marine structure on a lot.
- Harbor Ordinance Sec. 7.5(i), Floats and Lobster Cars, Harbor Ordinance (as amended May 5, 2026), p. 12
Floats and Lobster Cars - All floats (commercial and private) and lobster cars must be registered with the Harbor Master's office and shall have a mooring on each end that meets the minimum mooring specification in this Ordinance.
- Sec. 6C.7.12, Dimensional limits, Land Use Zoning Ordinance, p. 88
Notwithstanding the dimensional limits below, in areas where the horizontal distance from the normal high-water line to the mean lower low water is in excess of 160 feet, no permanent structure will be allowed seaward of the upland edge of a coastal wetland.
- Sec. 6C.7.8, Height limit, Land Use Zoning Ordinance, p. 87
Except in the Shoreland Commercial District, structures built on, over or abutting a pier, dock, wharf, or other structure extending below the normal high-water line of a water body or within a wetland shall not exceed twenty (20) feet in height above the pier, wharf, dock, or other structure.