Plymouth County, MA Environmental Rules: Coastal Development (2026)
Key Facts
- License
- Chapter 91 from MassDEP
- Applies To
- Docks, piers, seawalls, fill
- Trigger
- Work below high-water mark
- Also Required
- Conservation commission order
Summary
Building a dock, pier, seawall, or placing fill below the high-water mark along Plymouth County's coast requires a Chapter 91 waterways license from MassDEP. Coastal wetlands, beaches, and dunes are also protected under the Wetlands Protection Act.
The department may license and prescribe the terms for the construction or extension of a dam, road, bridge, or other structure, or the filling of land
Full Breakdown
Plymouth County's Cape Cod Bay and Buzzards Bay shorelines, from Plymouth, Duxbury, Marshfield, and Scituate to Wareham, Marion, and Mattapoisett, sit on public tidelands. Under Chapter 91, MGL c.91 §12, MassDEP licenses structures and the filling of land in these waterways, including docks, piers, floats, seawalls, and revetments. Any work below the mean high-water mark needs a Chapter 91 license, and most coastal projects also need an order of conditions from the conservation commission under the Wetlands Protection Act. Filling tidelands without authorization is treated as a public nuisance the state can order removed.
Violations & Fines
Building a dock, seawall, or fill in tidelands without a Chapter 91 license is an unauthorized encroachment on public trust land. MassDEP can order removal and impose penalties, and the structure is a public nuisance.
Frequently Asked Questions
Do I need a license to build a dock in Plymouth County?
What happens to unlicensed coastal structures?
Sources & Official References
Other rules in Plymouth County
Compare Plymouth County to another location·View the Massachusetts environmental rules overview
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