Dock, pier and float rules in Dennis, Massachusetts
Possibly, with a Conservation Commission Order of Conditions plus state approvals. Dennis allows docks as water-dependent uses but won't permit new or bigger docks that would harm shellfish habitat. Docks need at least 3 feet of water at mean low tide without dredging, piers and walkways can be no wider than 4 feet and cross no more than 150 feet of marsh or flats, and floats can be no wider than 10 feet.
| Town approval | Conservation Commission (Notice of Intent, Order of Conditions); engineer-stamped plans [1] |
| Minimum water depth | 3 ft at mean low water without dredging [2] |
| Pier/ramp/boardwalk width and length over marsh/flats | Max 4 ft wide; cross no more than 150 ft of saltmarsh, wetlands, flats or shellfish areas [3] |
| Float width | Max 10 ft [4] |
| Construction | Open pile only, no solid fill; no creosote or CCA lumber [5] |
| Shellfish habitat | New/expanded docks not permitted if they harm shellfish or aquaculture areas [6] |
| Moored float not attached to shore | Harbormaster Type 4 (10A float) permit [7] |
These rules come from the Conservation Commission's 2011 regulations, the version the town posts, and may have been amended since.
Conservation Commission review
Docks, piers, ramps, floats and boardwalks are "dock facilities" under Section 3 of the Conservation Commission's Rules and Regulations. They need an Order of Conditions under the Dennis Wetlands Protection Bylaw. Plans must be stamped by a Professional Engineer and show property lines and one-foot bathymetric contours [1]. Copies go to the Shellfish Constable and Harbormaster, who have 10 working days to comment. Docks count as water-dependent uses, so they are exempt from the Commission's 50-foot no-disturb rule. Zoning also lets docks and boathouses sit within the 50-foot water setback.
Design limits
- Water depth: at least 3 feet at mean low water, without dredging [2].
- Size: piers, ramps and boardwalks may cross no more than 150 feet of saltmarsh, vegetated wetland, mud flats or mapped shellfish habitat. They may be no wider than 4 feet and must be raised at least 1 foot for each foot of width [3]. Floats may be at most 10 feet wide [4].
- Construction: open-pile only, with no solid fill and no creosote or CCA-treated lumber [5]. Fabricate in an upland area when practicable. Passage along the shore must be kept open at all tide levels.
Shellfish protection
New or enlarged dock facilities won't be permitted if building or using them would harm shellfish, shellfish habitat or aquaculture areas, including through boat traffic. The Commission may allow it only if mitigation would actually enhance protection [6]. This is the most common reason docks are denied.
Moored floats and other approvals
A floating dock moored offshore (not attached to land) is a "10A float" and needs a Harbormaster Type 4 permit [7]. Docks in tidal or great-pond waters also need state Chapter 91 licensing and federal permits (see the state section). North of Route 6, freshwater seasonal docks can get an Old King's Highway exemption once all other permits are in hand.
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Next steps
- Contact the Dennis Conservation Commission and Harbormaster early to check shellfish areas, water depth, and channel distance at your site.
- Hire a Professional Engineer to prepare stamped plans with property lines, one-foot bathymetry, and shellfish/eelgrass survey data.
- File a Notice of Intent with the Conservation Commission; copies go to the Shellfish Constable and Harbormaster.
- Apply for state Chapter 91 (MassDEP) and federal (Army Corps) authorizations; for a moored float, apply to the Harbormaster for a 10A float permit.
Common questions
- Do I need a permit to build a dock in Dennis, MA?
- Yes. A dock needs a Conservation Commission Order of Conditions under the Dennis Wetlands Protection Bylaw, with engineer-stamped plans, plus state Chapter 91 and federal Army Corps approvals.
- How big can a dock be in Dennis, Massachusetts?
- Piers, ramps and walkways can be no wider than 4 feet and cross no more than 150 feet of marsh, wetlands, flats or shellfish areas. Floats can be no wider than 10 feet, and docks need at least 3 feet of water at mean low tide without dredging.
- Why are docks denied in Dennis, MA?
- Most often for shellfish protection. Dennis won't permit new or bigger docks that would harm shellfish, shellfish habitat or aquaculture areas unless mitigation would actually enhance protection.
- Do I need a permit for a moored float in Dennis, Massachusetts?
- Yes. A floating dock moored offshore and not attached to shore needs a Harbormaster Type 4 (10A float) permit.
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 3.1(a) General Conditions, Conservation Commission Rules & Regulations (effective May 19, 2011), p. 12
All dock facilities plans shall be prepared and stamped by a Professional Engineer as deemed appropriate by the Commission. All plans shall show property lines and bathymetric information at one foot contour intervals.
- Section 3.1(d), Conservation Commission Rules & Regulations (effective May 19, 2011), p. 13
All docking and loading facilities shall require a minimum of three (3) foot depth at mean low water without benefit of dredging.
- Section 3.2(c) Construction Requirements (sentence continues onto p.14), Conservation Commission Rules & Regulations (effective May 19, 2011), p. 13
Piers, ramps and boardwalks shall cross no more than one hundred fifty (150) feet of saltmarsh, vegetated wetlands, mud flats or mapped shellfish/shellfish habitat areas, shall be no wider than four feet and elevated a minimum of one foot in height for each one foot of width above existing grade.
- Section 3.2(d), Conservation Commission Rules & Regulations (effective May 19, 2011), p. 14
Floats shall be limited to a maximum width of ten feet.
- Section 3.2(a)-(b), Conservation Commission Rules & Regulations (effective May 19, 2011), p. 13
Dock facilities shall not be constructed with materials containing creosote or CCA. b. Piers, ramps and boardwalks shall be limited to open pile supported construction. No solid fill shall be used.
- Appendix B: New or Expanded Dock Facilities, Conservation Commission Rules & Regulations (effective May 19, 2011), p. 22
In order to maximize protection of shellfish and associated habitat areas recognized by the Town of Dennis to be significant to public resources, the construction of new and/or the enlargement of existing dock facilities shall not be permitted if their construction or use would result in any adverse effect/significant effect to shellfish, habitat and/or aquaculture areas.
- Section 7(C)(4) Mooring permit types, Waterways Regulations (Select Board; adopted Jan 5, 2016, amended through Jan 7, 2020), p. 12
Type 4 – 10A Float: A Type 4 permit may be issued to an individual for a moored floating dock not connected to the shore and shall allow the permit holder to moor their float at a location designated by the Harbormaster.