Dock, pier and float rules in Plymouth, Massachusetts
A private pier, dock or float in Plymouth needs a permit from the Conservation Commission, because driving piles or placing docks and floats in water counts as altering a protected resource area. On great ponds, a swim raft or moored float needs a Harbormaster mooring permit, can be no larger than 100 sq ft, must stay within 100 feet of shore, and must be out of the water from December 1 to May 1.
| Town approval | Conservation Commission permit (Notice of Intent) for piers, docks, floats and pilings [1] |
| Pond raft max size | 100 sq ft surface area [4] |
| Pond raft / mooring distance | No more than 100 ft from shore [6] |
| Seasonal removal (ponds) | Out by December 1, not replaced until May 1 [6] |
| Who can apply (ponds) | Waterfront owner, or someone with the owner's permission, for a spot next to the property [3] |
Conservation Commission review
Under Plymouth's wetlands regulations, "altering" a protected area includes driving piles, erecting buildings and placing obstructions or objects in water [2], and obstructions in water are defined to include piers, docks, pilings, slips and floats [1]. The wetlands bylaw requires a Notice of Intent and a permit before any regulated activity [5], so a new or rebuilt private dock, pier or float on the ocean, a river or a pond needs Conservation Commission approval.
Floats and rafts on great ponds
The Harbormaster's Official Waterway Regulations (effective December 16, 2025) cover moorings, floats and rafts in town waterways. On great ponds, only a waterfront owner, or someone with the owner's permission, can apply for a mooring permit for a temporary bottom-moored float, raft or boat next to the property, and these structures must be removed before December 1 and not put back until May 1 [3][6]. A raft, meaning a free-floating dock anchored to the bottom and not connected to shore, may be no larger than 100 sq ft, must be within 100 feet of shore and can't be painted with toxic coatings [4].
Harbor and state permits
The town's harbor bylaw (Chapter 81) deals with town floats, piers, ramps and moorings, not private pier permits. The local documents we reviewed don't set size limits for shore-connected private piers; those are governed by state Chapter 91 waterways licensing for tidelands and great ponds and, in navigable waters, U.S. Army Corps of Engineers permits.
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Next steps
- Talk to the Plymouth Conservation Commission about your dock or pier plan, then file a Notice of Intent with plans and the fee.
- Apply to MassDEP for a Chapter 91 waterways license (tidelands or great ponds) and check whether you need an Army Corps permit.
- For a swim raft or moored float on a great pond, apply to the Harbormaster with a parcel map, GPS location, owner information and gear specs; keep it under 100 sq ft and within 100 ft of shore.
- Remove pond moorings and rafts before December 1 and don't reinstall until May 1.
Common questions
- Do I need a permit to build a dock in Plymouth, MA?
- Yes. A private pier, dock or float in Plymouth needs a Conservation Commission permit (Notice of Intent), because driving piles or placing docks and floats in water counts as altering a protected resource area. State Chapter 91 and Army Corps permits may also apply.
- How big can a swim raft be on a pond in Plymouth, Massachusetts?
- On great ponds, a raft can be no larger than 100 sq ft, must be within 100 feet of shore, can't be painted with toxic coatings, and needs a Harbormaster mooring permit.
- When do docks and rafts have to come out of ponds in Plymouth, MA?
- Pond moorings, floats and rafts must be removed before December 1 and can't be put back until May 1.
- Who can apply for a pond mooring permit in Plymouth, Massachusetts?
- Only a waterfront owner, or someone with the owner's permission, for a spot next to the property.
Massachusetts state rules for docks and piers
A private dock in Massachusetts usually needs several layers of approval beyond local zoning.
Chapter 91 waterways license (MassDEP): any structure, regardless of size, permanent or seasonal, in tidal waters, in a great pond (a pond over 10 acres in its natural state), or in certain navigable rivers needs Chapter 91 authorization (M.G.L. c. 91; 310 CMR 9.00). For small residential docks there are simpler routes:
- a General License certification for pile-supported residential docks, piers, ramps and floats with no fill or dredging, outside ACECs and Designated Port Areas (310 CMR 9.29)
- a Simplified License for residential docks up to 600 sq ft below the high-water line (310 CMR 9.10)
Licenses must be recorded at the Registry of Deeds, and Chapter 91 protects public rights to fish, fowl and navigate.
Conservation Commission: dock work in or near wetlands, banks or land under water needs an Order of Conditions under the Wetlands Protection Act (c. 131, §40).
Harbormaster: bottom-anchored moorings, floats and rafts (no pilings) can be authorized by an annual permit from the local harbormaster instead of a Chapter 91 license (c. 91, §10A). Mooring fees can't discriminate based on residence.
U.S. Army Corps of Engineers: work in navigable waters may also need federal approval. Small private piers and floats are often covered by the Corps' Massachusetts General Permits, which can involve self-verification or pre-construction notification.
What the bylaw says
- Section 5 Definitions, Obstructions or Objects in Water, Rules and Regulations for Plymouth Wetlands Protection Bylaw (Current Version 2025, incl. FTM 2024 Art. 8 vernal pool revision), p. 11
Obstructions or Objects in Water means but is not limited to dams, weirs, sluice gates, jetties, groins, breakwaters, piers, docks, sea walls, bulkheads, pilings, dolphins, marine railways, slips and floats.
- Section 5 Definitions, Alter (5), Rules and Regulations for Plymouth Wetlands Protection Bylaw (Current Version 2025, incl. FTM 2024 Art. 8 vernal pool revision), p. 8
5. Driving of piles or erection of buildings, placing of obstructions or objects in water (other than boats, fish, or shellfish traps, pens or trays used in conjunction with aquiculture, or aids to navigation).
- V. Mooring Regulations - Great Ponds, E.1, Official Waterway Regulations (approved December 16, 2025), p. 8
1. Applicants requesting a mooring permit for a bottom moored temporary float, raft or boat mooring shall own or have permission from a waterfront landowner to apply for a mooring directly adjacent to the property.
- V. Mooring Regulations - Great Ponds, G. Rafts, Official Waterway Regulations (approved December 16, 2025), p. 9
1. Rafts are defined as any free-floating dock anchored to the bottom and not connected to shore. 2. No raft will be larger than 100 square feet in surface area.
- § 196-8.A Notice of intent, General Bylaws Chapter 196, Wetlands Protection, p. 7
No activities regulated hereunder shall commence without a permit issued pursuant to this chapter.
- V. Mooring Regulations - Great Ponds, F.3, Official Waterway Regulations (approved December 16, 2025), p. 8
3. All temporary structures (moorings) must be removed prior to December 1st and not replaced until May 1st of each calendar year. 4. No mooring or raft shall be placed further than 100’ from shore.