CityOfBoston Official An official website of the City of Boston

This is the website for the City of Boston’s new Planning Department, which launched on July 1. The staff and many responsibilities of the Boston Planning & Development Agency have moved to the Planning Department of the City of Boston including planning & zoning, urban design, development review, and real estate divisions. Please excuse any misalignment you may see on our site as we transition to the City. Learn more

The Site Compliance team works closely with the State to review and manage projects that are subject to the State’s Public Waterfront Act (MGL Chapter 91) and approved Municipal Harbor Plans (MHPs). Chapter 91 and MHPs provide direction for future waterfront development, detailed below.

Chapter 91, The Massachusetts Public Waterfront Act

Chapter 91, The Massachusetts Public Waterfront Act, was created in 1866 to regulate waterways within the Commonwealth. Its purpose is to preserve and protect the rights of the public, establish priority for water-dependent uses, and guarantee that private uses in tidelands and along waterways serve a proper public purpose. The original legislation focused on the public’s right to fishing, fowling, and navigation on waterways but has been expanded to include filled tidelands and to promote a broad spectrum of water-dependent activities.

Non Water-dependent uses are those projects that may be located on waterfront property, but do not require close proximity to water to maintain functionality. As per the regulating legislation, if any portion of a project is deemed non water-dependent, the entire project will be considered as a non water-dependent use. To ensure that non water-dependent use projects serve a proper public purpose, they must provide a net benefit to the public’s rights in waterways. The non water-dependent use standards with which most developments must comply are:¹

  1. Building Height: Within 100’ of the MHHW, buildings are restricted to 55’ in height, with an additional 1’ of height allowed for every two additional feet of horizontal distance from the project shoreline.
  2. Water-Dependent Use Zone: For projects with a water-dependent use zone, standards must be met to provide a water-dependent use on site, such as water taxi or HARBORWALK.
  3. Open Space: Generally, there is a 1:1 ratio required for open space. That is, for ever square foot of built land on the parcel, one square foot of open space should be created on site.
  4. Facilities of Public Accommodation: Facilities of Public Accommodation are required on the ground level of all building on Commonwealth tidelands.

The State Department of Environmental Protection administers Chapter 91 through the Code of Massachusetts Regulations, 310 CMR 9.00 Waterways.


Within the Commonwealth, Chapter 91 covers the following geographies:²

  1. Flowed Tidelands - Any project located in, on, over or under tidal waters seaward of the present mean high water (MHW) shoreline. Jurisdiction in this case extends seaward three miles, to the state limit of territorial jurisdiction.
  2. Filled Tidelands - The limit on filled tidelands is: A.) Outside Designated Port Areas, the first public way or 250 feet from mean high water, whichever is farther landward and B.) Inside Designated Port Areas, the historic MHW shoreline (i.e., all filled areas).
  3. Great Ponds - Any project located in, on, over or under the water of a great pond. A great pond is defined as any pond or lake that contained more than 10 acres in its natural state. Ponds or lakes presently larger than 10 acres are presumed to be great ponds, unless the applicant provides unequivocal evidence to the contrary. Ponds 10 or more acres in their natural state, but which are now smaller, are still considered great ponds.
  4. Non-Tidal Rivers and Streams - Projects located in, on, over, or under any non-tidal, navigable river or stream on which public funds have been expended either upstream or downstream within the river basin, except for any portions not normally navigable during any season by any vessel. Additionally, the Connecticut River, the Merrimack River and portions of the Westfield River are within jurisdiction.

Landlocked tidelands, which are filled tidelands that as of January 1, 1984 were entirely separated from flowed tidelands by a public way, are generally not within Chapter 91 jurisdiction.

Special Conditions

For land subject to Chapter 91, there are special cases under which the regulations may differ. Designated Port Areas and areas subject to Municipal Harbor Plans contain additional regulations that govern use and dimensional restrictions for a project site.

Designated Port Areas

Designated Port Areas (DPAs) are areas delineated by the Office of Coastal Zone Management for the purpose of limiting shoreline development to protect water-dependent industrial uses. As per CZM, DPAs have three key attributes:³

  1. Waterway and associated waterfront developed to accommodate commercial navigation or other industrial utilization of the water.
  2. Landside space with physical and use character that supports siting of industrial facilities/operations.
  3. Appropriate land-based transportation routes and utilities for industrial use.

Allowable uses within DPAs are specific to the needs of industrial areas. Allowable uses within DPAs include water-dependent industrial uses, accessory uses, temporary uses, supporting DPA uses, and compatible public access that does not interfere with industrial needs.

DPAs occupy 2% of the Massachusetts coastline, and a significant portion of the coastline of Boston. There are ten total Designated Port Areas within the Commonwealth, five of which apply to the Boston area:

  • Mystic River DPA
  • Chelsea Creek DPA
  • East Boston DPA
  • South Boston DPA and;
  • Weymouth Fore River DPA

Municipal Harbor Plans

Municipal Harbor Plans (MHPs) are a tool used to promote long term waterfront planning goals within specified boundaries. MHPs are documents that allow for alterations to the Chapter 91 standards in an effort to implement community vision in waterfront areas, including but not limited to the creation of new civic and cultural amenities, open space, and the provision of water transportation infrastructure.

MHPs must be approved by the State, and are part of a voluntary planning process. MHPs create approved substitute provisions to replace Chapter 91 standards from non water-dependent projects. These substitute provisions must be offset by activating the waterfront to a greater degree than under the general standards of Chapter 91.

To view existing Municipal Harbor Plans visit the Planning Initiatives page.


For questions regarding Ch. 91 projects, contact [email protected]

¹This is not a complete list of regulations. For a complete list, see 310 CMR 9.00

²Subsequent text from

³Text from MA Designated Port Area Slides