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Building near the water in Nantucket, Massachusetts (wetlands rules)

Nantucket, Nantucket County · Bylaws checked 2026-10-03 · Reviewed · 13 cited sections

Allowed with board review

Any work within 100 feet of a wetland, beach, dune, coastal bank, pond or marsh needs a filing with the Nantucket Conservation Commission. The local regulations keep a 25-foot undisturbed buffer and a 50-foot structure-free zone, and new non-water-dependent structures must generally be at least 75 feet from coastal beaches, dunes, banks and salt marshes (50 feet with buffer enhancement).

Conservation Commission jurisdictionAll work within the 100-ft buffer zone needs an RDA or Notice of Intent [1]
Undisturbed vegetated buffer25 feet [2]
Structure-free buffer50 feet [2]
Notice of Intent requiredFor work within 50 ft of a resource area [3]
Structure setback from coastal bank (also beach, dune, salt marsh)75 feet for non-water-dependent structures [4]
Reduced setback optionDown to 50 ft if the undisturbed buffer is enhanced by 1.5x the structure area in the 50-75 ft band [5]
Buildings near coastal dunesNo new building on a dune or within 50 ft of one [6]
Tree cutting in viewshed corridorsNo tree over 4" DBH may be cut down [10]

Where the rules apply

These rules come from the Conservation Commission's Chapter 390 regulations as posted by the town (titled in effect as of January 1, 2025); they may have changed since. Nantucket's Conservation Commission regulations (Chapter 390, under the Ch. 136 Wetlands Bylaw) cover wetland resource areas such as coastal beaches, dunes, coastal banks, salt marshes, ponds and flood-prone land, plus a 100-foot buffer zone around them. A Request for Determination of Applicability or a Notice of Intent must be filed for all activities in the buffer zone [1].

Setbacks

  • The Commission generally requires a 25-foot undisturbed vegetated buffer and a 50-foot structure-free buffer [2]. Work within 50 feet requires a Notice of Intent [3].
  • Near coastal banks (and likewise coastal beaches, dunes and salt marshes), non-water-dependent projects keep the 25-foot buffer, may disturb no more than half of the 25-50 foot band, and structures must be at least 75 feet away [4]. Structures can come to 50 feet if the undisturbed buffer is enhanced by 1.5 times the structure area between 50 and 75 feet [5].
  • No building may be built on a coastal dune or within 50 feet of one, other than repairing an existing structure [6].
  • On eroding shorelines, buildings must sit back at least 20 times the average annual erosion rate or 100 feet, whichever is less [7].

Existing structures

Structures that predate the state act (1972) or local bylaw (1983) may continue, but can't be extended or modified unless the Commission finds no adverse impact [8].

Vegetation and views

New vista cutting needs a Commission permit [9]. Each house gets one view corridor [12], and no tree larger than 4 inches DBH may be cut down [10]. Small projects between 50 and 100 feet, such as native plantings, unpaved paths or permitted view pruning, may qualify for a cheaper Minor Activity permit [11].

Flood zones

In land subject to coastal storm flowage, building where it would face storm damage or high-tide flooding may not be permitted [13].

See how Nantucket compares with 8+ other Massachusetts towns on building near the water (wetlands rules) →

Next steps

  1. Find out whether your lot is within 100 feet of a wetland resource area by contacting the Nantucket Conservation Commission (see the town website for contact details).
  2. For work 50-100 feet away, ask whether it qualifies for a Minor Activity permit or needs a Request for Determination of Applicability.
  3. For work within 50 feet, or any building near a beach, dune, bank or marsh, hire a wetland consultant to flag resource areas and file a Notice of Intent.
  4. Check with the PLUS Building Office (508-325-7587) for zoning and building permits once you have Conservation Commission approval.

Common questions

Do I need approval to build near a wetland or beach in Nantucket, Massachusetts?
Yes. Any work within 100 feet of a wetland, beach, dune, coastal bank, pond or marsh needs a filing with the Conservation Commission.
How far from the beach or marsh must a new structure be in Nantucket, Massachusetts?
New non-water-dependent structures must generally be at least 75 feet from coastal beaches, dunes, banks and salt marshes (50 feet with buffer enhancement).
What buffers apply near wetlands in Nantucket, Massachusetts?
The local regulations keep a 25-foot undisturbed buffer and a 50-foot structure-free zone.
Can I cut trees in a viewshed corridor in Nantucket, Massachusetts?
No tree over 4" DBH may be cut down.

Massachusetts wetlands rules and the Conservation Commission

Massachusetts has no "shoreland zoning" like some states. Instead, the Wetlands Protection Act (M.G.L. c. 131, §40) and MassDEP's regulations (310 CMR 10.00) control work near water, and your local Conservation Commission enforces them.

What's protected:

  • Wetlands, banks, beaches, dunes, marshes, land under ponds and streams, and 100-year floodplains.
  • The riverfront area: 200 feet from a perennial river or stream, shrinking to 25 feet in certain dense urban areas.
  • The buffer zone: land within 100 feet of a wetland, bank, beach or similar resource area. Most work here needs Conservation Commission review.

How approval works:

  • Contact the Conservation Commission before starting any work in these areas. That includes additions, decks, sheds, driveways, regrading and clearing vegetation.
  • If you're unsure whether the law applies, file a Request for Determination of Applicability (RDA).
  • If the work will affect a resource area, file a Notice of Intent (NOI) with plans and a fee. A public hearing follows, and the commission issues an Order of Conditions approving (with conditions) or denying the project.
  • Applicants, abutters, groups of 10 residents or MassDEP can appeal to MassDEP.

Local bylaws can be stricter. Many towns have their own wetlands bylaw with larger buffers or no-build zones, and the Conservation Commission enforces those too.

State sources: M.G.L. c. 131, §40 (Wetlands Protection Act) · 310 CMR 10.00, Wetlands Protection Act Regulations · MassDEP, Protecting Wetlands in Massachusetts

What the bylaw says

Exact text from Nantucket's published bylaws. Section numbers are as printed in the source.

  1. § 390-23. Findings; RDA or NOI required, Chapter 390: Wetlands Protection Regulations (Conservation Commission), in effect as of January 1, 2025, p. 49
    Therefore, a request for determination of applicability or notice of intent must be filed for all activities proposed within the buffer zone to these resource areas.
  2. § 390-26. Filing requirements and buffer zone setbacks, Chapter 390: Wetlands Protection Regulations (Conservation Commission), in effect as of January 1, 2025, p. 49
    Based on available information, the Commission has determined that, generally, maintenance of a twenty- five-foot undisturbed vegetative buffer zone and a fifty-foot structure-free buffer zone will serve to protect most wetland resource areas from adverse impacts related to development elsewhere within the buffer zone.
  3. § 390-26. Filing requirements and buffer zone setbacks, Chapter 390: Wetlands Protection Regulations (Conservation Commission), in effect as of January 1, 2025, p. 49
    Work proposed within 50 feet of a wetland resource area shall require the filing of a notice of intent.
  4. § 390-10B(5). Coastal banks, performance standards, Chapter 390: Wetlands Protection Regulations (Conservation Commission), in effect as of January 1, 2025, p. 30
    Proposed projects which are not water dependent shall maintain a 25-foot undisturbed buffer zone with no greater than 50% of the area between the twenty-five-foot buffer zone and fifty-foot setback disturbed. All structures which are not water dependent shall be located at least 75 feet from a coastal bank.
  5. § 390-7B(6). Coastal beaches, performance standards (Exception), Chapter 390: Wetlands Protection Regulations (Conservation Commission), in effect as of January 1, 2025, p. 25
    Exception: Structures shall be permitted down to the 50-foot setback provided that the undisturbed buffer zone is enhanced by 1.5X the structural area between the 50’ setback and 75’ setback in a manner contiguous with the undisturbed buffer zone.
  6. § 390-8B(7). Coastal dunes, performance standards, Chapter 390: Wetlands Protection Regulations (Conservation Commission), in effect as of January 1, 2025, p. 28
    No activity shall be permitted, other than the maintenance and repair of a structure existing on the effective date of these regulations, that will result in construction of a building upon a coastal dune or within 50 feet of any coastal dune.
  7. § 390-7B(7). Coastal beaches, performance standards, Chapter 390: Wetlands Protection Regulations (Conservation Commission), in effect as of January 1, 2025, p. 25
    In areas of eroding shoreline, the distance from all buildings to the coastal beach shall be at least 20 times the average annual shoreline erosion or 100 feet, whichever is less.
  8. § 390-2. Definitions, Grandfathering/Preexisting Use, Chapter 390: Wetlands Protection Regulations (Conservation Commission), in effect as of January 1, 2025, p. 8
    1) Existing structures, uses and/or alterations of land may not be extended and/or modified unless such extension or modification is permitted by a finding of the Commission that such alteration or modification shall have no adverse impact on the resource areas and interests protected by the Town of Nantucket Wetlands Protection Bylaw.
  9. Appendix D, Viewshed Management Guidelines, Chapter 390: Wetlands Protection Regulations (Conservation Commission), in effect as of January 1, 2025, p. 57
    No new vista cutting is allowed without first receiving a permit from the Nantucket Conservation Commission.
  10. Appendix D, Viewshed Management Guidelines, Trees (1), Chapter 390: Wetlands Protection Regulations (Conservation Commission), in effect as of January 1, 2025, p. 58
    1. No tree greater than 4” DBH (diameter at breast height) shall be cut down. Any tree to be removed must be reviewed by Commission staff.
  11. § 390-3G. Minor Activities, Chapter 390: Wetlands Protection Regulations (Conservation Commission), in effect as of January 1, 2025, p. 17
    Applicability: Minor projects are defined as those that occur outside of the 50’ setback but inside the 100’ buffer zone or within the Great Pond Area.
  12. Appendix D, Viewshed Management Guidelines, General Guidelines (1), Chapter 390: Wetlands Protection Regulations (Conservation Commission), in effect as of January 1, 2025, p. 57
    1. Each residential structure shall be allowed one viewshed corridor. Corridors may be no more than 15 feet from top to bottom and shall be 20’ wide at the end closest to the structure and 25 feet on the resource area side of the corridor.
  13. § 390-15B(4). Land subject to coastal storm flowage, Chapter 390: Wetlands Protection Regulations (Conservation Commission), in effect as of January 1, 2025, p. 37
    4) Building upon areas subject to coastal storm flowage and sea-level rise in locations where such structure would be subject to storm damage or high-tide flooding may not be permitted.
This page summarizes Nantucket's posted bylaws as of 2026-10-03. Bylaws are amended, and individual lots can have overlays, subdivision covenants, or HOA rules that are stricter. Confirm with Planning & Land Use Services (PLUS) - Building Office (508-325-7587) before you build. Spot an error?