Log in links for this page

Massachusetts Ocean Sanctuaries

Find information on these specified marine areas that are protected from actions that would alter or endanger their ecology and appearance.

The Massachusetts Ocean Sanctuaries Act establishes five Ocean Sanctuaries in state waters and defines prohibited and allowed activities in these areas. The Act also requires the Executive Office of Energy and Environmental Affairs (EEA) and its agencies to protect the Ocean Sanctuaries from exploitation, development, or activities that would significantly alter or otherwise endanger their ecology or appearance when authorizing activities under jurisdiction. The Massachusetts Office of Coastal Zone Management (CZM) is responsible for the care, oversight, and control of Ocean Sanctuaries and works with EEA agencies to implement the Ocean Sanctuary regulations at 301 CMR 27.00.

This web page provides an overview of the Ocean Sanctuaries program, organized into the following topic areas: Authorities, Ocean Sanctuary Boundaries, Allowed and Prohibited Activities, History of Ocean Sanctuaries, and Ocean Outfalls.


Ocean Sanctuary Boundaries

There are five Ocean Sanctuaries: Cape Cod, Cape Cod Bay, Cape and Islands, North Shore, and South Essex. These Ocean Sanctuaries include most of Massachusetts marine waters except for Mount Hope Bay and an area of Massachusetts Bay from the Lynn/Swampscott border to Brant Rock in Marshfield. The seaward boundary of the sanctuaries is the limit of state waters, generally three miles offshore. The landward boundary is the mean low water mark along the shore—but in all rivers, bays, harbors, and coves, the landward boundary extends to where the distance across the water body narrows to 200 yards, measured at the mean low water lines. The boundaries are described at M.G.L. c. 132A, § 13. Official maps of the Ocean Sanctuaries are developed and maintained by CZM.

Allowed and Prohibited Activities

The history of Ocean Sanctuaries in Massachusetts stretches back to 1970 (see History of Ocean Sanctuaries below), and the allowed and prohibited activities in the sanctuaries have evolved over time. The lists below summarize the current allowed and prohibited activities in Ocean Sanctuaries. For a complete list of allowed and prohibited activities, refer to the regulations at 301 CMR 27.05.


  • Transient, vessel-based activities.
  • Commercial and recreational fishing.
  • The operation and maintenance of existing municipal, commercial, or industrial facilities.
  • A new or modified discharge of municipal wastewater.
  • Discharges from vessels, except sewage.
  • Dredging for navigational purposes.
  • The extraction of sand and gravel for beach nourishment.
  • The harvesting and propagation of fish and shellfish in all forms.
  • Temporary educational and scientific activities.
  • The construction and operation of offshore or floating renewable energy generating facilities, except in the Cape Cod Ocean Sanctuary.
  • The laying of cables approved by the Department of Public Utilities or the Department of Telecommunications and Cable.
  • Channel and shore protection projects.
  • Navigational projects and aids.
  • Projects authorized under M.G.L. c. 91 and 310 CMR 9.00 deemed to be of public necessity and convenience, including but not limited to natural gas lines, water mains, and wastewater and stormwater pipes.

Prohibited Unconditionally

  • Drilling or removal of gases or oils.
  • Commercial advertising, where advertising is the primary intent.
  • Incineration of refuse on, or in, vessels.

Prohibited with Exceptions

  • The dumping or discharge of commercial, municipal, domestic, or industrial wastes except as allowed in Ocean Sanctuary regulations 301 CMR 27.05(2). This includes discharges from facilities covered by the U.S. Environmental Protection Agency and Massachusetts Department of Environmental Protection National Pollutant Discharge Elimination System Groundwater Remediation General Permits and Wastewater General Permits.
  • The drilling or removal of minerals, including sand and gravel, except for beach nourishment.
  • The construction or operation of offshore or floating electric generating stations except renewable energy facilities.
  • The building or laying of structures on the seabed or subsoil, except as allowed in the Ocean Sanctuary regulations at 301 CMR 27.05(2).

History of Ocean Sanctuaries

The original intent of the first Ocean Sanctuary designation in 1970 was to protect the designated area from any exploitation, development, or activity that would seriously alter or otherwise endanger the ecology or the appearance of the ocean or seabed or the adjacent Cape Cod National Seashore. Then Governor Sargent stated to the Secretary of the Commonwealth that the establishment of this sanctuary was an emergency law to “protect the unique scenic and natural resources of the outer Cape by preventing careless exploitation of the seabed,” in part in response to interest in exploring oil and gas reserves off the coast of Massachusetts. The nearshore boundary of the Ocean Sanctuary was mean low water and the offshore boundary was the state/federal boundary.

The Massachusetts Ocean Sanctuaries boundaries and activities prohibited and allowed within them have been modified over the years, as summarized below.

  • The Cape Cod Ocean Sanctuary was the first Ocean Sanctuary, established by Chapter 542 of the Acts of 1970. This act established the lists of prohibited and allowed activities in Ocean Sanctuaries and set the nearshore boundary at mean low water.
  • Chapter 742 of the Acts of 1971 established the Cape Cod Bay and Cape and Islands Ocean Sanctuaries. The prohibited activities in Ocean Sanctuaries were amended to allow an exception for the discharge of industrial liquid coolant wastes associated with the generation of electrical power.
  • Chapter 130 of the Acts of 1972 established the North Shore Ocean Sanctuary.
  • Chapter 369 of the Acts of 1976 established the South Essex Ocean Sanctuary. The language establishing this sanctuary created a new prohibition on the construction of electric generating stations in all five sanctuaries. This law also specifically allowed discharges from municipal waste treatment facilities that were constructed prior to January 1, 1978, so long as the discharge was in accordance with state requirements.
  • Chapter 897 of the Acts of 1977 clarified how to establish the nearshore boundary of the Ocean Sanctuaries. This act stated that mean low water is the “arithmetic mean of the low-water heights observed over a specific 19-year Metonic cycle (the National Tidal Datum Epoch) and shall be determined using the nautical charts, harbor charts series (1:50,000 and larger) prepared by the National Ocean Survey, U.S. Department of Commerce.” This act also declared that Ocean Sanctuaries “shall include all islands lying within the aforementioned boundaries seaward of the mean low-water lines of each such island.” In addition, this act prohibited the construction or operation of offshore or floating electric generating stations in Ocean Sanctuaries.
  • Chapter 120 of the Acts of 1981 allowed the City of Gloucester an exception to the prohibition on wastewater facility construction and discharges after 1978. This exception allowed the City to receive a waiver from secondary wastewater treatment requirements from the U.S. Environmental Protection Agency (EPA). Through this waiver, the City was allowed special dispensation from upgrading its facility to a higher treatment capacity so long as it extended its outfall beyond the inner harbor.
  • Chapter 369 of the Acts of 1984 provided special dispensation to the Town of Dartmouth to improve its wastewater treatment facility and outfall and increase the volume of its ocean discharge to Buzzards Bay, provided that there was no other disposal method, including land application, that could be approved by the agencies; that such improvements and increase were consistent with sections 13-18 of MGL C. 132A (the Oceans Act) and were of equal or greater effectiveness in avoiding degradation of water quality in the sanctuary as well as surface and ground waters; and that the discharge would have, at a minimum, secondary treatment.
  • Chapter 728 of the Acts of 1989 officially named Massachusetts General Law (MGL) Chapter 132A Sections 12B-16E and Section 18 as the Ocean Sanctuaries Act and introduced new elements to the Ocean Sanctuaries including: 1) if certain conditions were met, the state could issue a variance allowing a new or modified municipal wastewater treatment discharge to an Ocean Sanctuary; 2) the application of treated wastewater to an upland area needed to be evaluated and was preferred (an ocean outfall would only receive a variance if land application was not feasible); and 3) discharges to estuaries or embayments were prohibited. The seaward boundary of the Plymouth-Kingston-Duxbury embayment was formally delineated as a line from Gurnet Point to Rocky Point in Plymouth, thereby excluding any new or modified outfalls landward of that line. Also, the Town of Gosnold was given special dispensation to build a primary wastewater treatment facility that could discharge to the Cape and Islands Ocean Sanctuary.
  • Chapter 114 of the Acts of 2008, also called An Act Relative to Oceans, made several significant changes to the Ocean Sanctuaries Act. First, it created the Ocean Resources and Waterways Trust Fund to accept fees that compensate for ocean development projects and whose uses are to restore or enhance marine habitat and resources impacted by the project. The Act also established an ocean planning area (PDF, 5 MB), beginning 0.3 nautical mile from the Massachusetts mean high water line to the state/federal boundary. In addition, the Act required the state to create an integrated ocean management plan to balance responsible ocean development with the protection of existing uses and resources. Lastly, the Act allowed for renewable energy generating facilities in all Ocean Sanctuaries except the Cape Cod Ocean Sanctuary. See Massachusetts Ocean Management Plan for details.
  • Chapter 259 Sections 28-45 of the Acts of 2014 allowed for new or modified municipal wastewater discharges to any Ocean Sanctuary, without a variance, but only after specific requirements were met, including tertiary treatment and dechlorinated effluent at new or modified discharges in Cape Cod, Cape and Islands, and Cape Cod Bay Ocean Sanctuaries, as well as modeling and marine studies to ensure that new discharges protect the appearance, ecology, and marine resources of the Ocean Sanctuary (301 CMR 27.06). This act maintained the prohibition on new municipal wastewater discharges to Plymouth-Kingston-Duxbury Bay.

Ocean Outfalls

The following is a list of permitted discharges to Massachusetts Ocean Sanctuaries and the water bodies they discharge to.

North Shore Ocean Sanctuary

  • Newburyport Water Pollution Control Facility - Merrimack River
  • Rockport Wastewater Treatment Facility - Sandy Bay

South Essex Ocean Sanctuary

  • Gloucester Water Pollution Control Facility - Massachusetts Bay
  • Manchester Wastewater Treatment Plant - Salem Sound
  • South Essex Sewerage District - Salem Sound

Cape Cod Bay Ocean Sanctuary

  • Plymouth Wastewater Treatment Plant - Plymouth Bay
  • Plymouth Nuclear Power Station – Cape Cod Bay
  • Canal Station – Cape Cod Canal

Cape Cod Ocean Sanctuary

  • No wastewater discharges

Cape and Islands Ocean Sanctuary

  • Massachusetts Maritime Academy - Cape Cod Canal
  • Dartmouth Water Pollution Control Facility - Buzzards Bay
  • New Bedford Wastewater Treatment Facility - Buzzards Bay

There are other wastewater treatment facilities in the coastal zone, but they either discharge to tributaries upstream of an Ocean Sanctuary (Amesbury, Salisbury, The Governor’s Academy, Ipswich, Residences at Shorecliff, Wareham, Marion, Fairhaven), or discharge to marine waters that have not been designated as an Ocean Sanctuary (Lynn, Massachusetts Water Resources Authority, Hull, Cohasset, Scituate, Marshfield, Fall River, Somerset, Taunton).

Help Us Improve Mass.gov  with your feedback

Please do not include personal or contact information.