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MassDEP Targets Cape Cod’s Nitrogen Pollution with New Watershed and Septic System Regulations

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MassDEP Targets Cape Cod’s Nitrogen Pollution with New  Watershed and Septic System Regulations MASS-DEP

The Massachusetts Department of Environment Protection (“MassDEP”) has amended its Septic System (“Title 5”) Regulations (310 CMR 15.000) and its Watershed Permit Regulations (314 CMR 21.00).

These new regulations were promulgated in tandem and took effect the same day—July 7, 2023. There are some stressed watershed designations effective immediately, timetables and options for actions applicable to Cape Cod towns, and retrofit requirements that will apply to septic system owners depending on what town you are in, what watershed, and what is your septic systems level of nitrogen compliance.

The target of these new rules is Cape Cod nitrogen pollution well documented in waterbodies. Basically, MassDEP using its state Clean Water Act authority has required the 11 towns on the Cape to remediate the excess nitrogen in Cape Cod waters. In communities that do not do so, owners of septic systems will have new obligations to meet within deadlines a few years out.

These new rules arose out of a settlement of a court case brought by the Conservation Law Foundation of New England, Inc. (CLF) against the Towns of Barnstable and Mashpee for alleged non-compliance with laws governing discharges of sewage. MassDEP agreed to develop and promulgate these regulations, which it has done after several months of drafting, consultation and public comment.

These two sets of regulations work together as carrot and stick, with the Watershed Permit Regulations as the carrot and the Title 5 Regulations as the stick. Communities must follow the steps outlined in the amended Watershed Permit Regulations. Otherwise, requirements are triggered for newly constructed and existing septic systems.


The Massachusetts Clean Water Act, M.G.L. c, 32, §§ 26 through 53, charges the MassDEP with the duty to protect public health and enhance the quality and value of the water resources in the Commonwealth. Under this statute, groundwater is included as a protectable water of the Commonwealth. MassDEP fulfills its duty regarding this publicly protected resource in part by regulating septic systems and issuing watershed permits.

A watershed is an area of land that drains into a specific body of water. Massachusetts is divided into 32 major watersheds, and many smaller watersheds. Cape Cod is its own large watershed (it all drains to the ocean) plus there are many smaller watersheds in it. MassDEP’s new Septic System Regulations and Watershed Permit Regulations only affect Cape Cod (for now).

The catalyst for the new regulations is nitrogen pollution in Cape Cod coastal estuaries and embayments, which is a problem also affecting the Islands and Southeastern Massachusetts. Septic systems are the major contributor of nitrogen polluting groundwater and waterbodies. On Cape Cod, 85% of waste water systems are septic systems.

Excess nitrogen in waterbodies produces eutrophication (excessive and premature aging), which causes plant life in the water (algae and invasive plants and weeds) to increase so much so that animals in the water die due to a lack of oxygen. Today, many of the bays and estuaries on Cape Cod violate state water quality standards for nitrogen based on the waterbodies’ use.

Until now there were no state regulatory requirements to reduce nitrogen from septic systems except near drinking water wells. Title 5 regulations long ago set certain limitations on the amount of nitrogen that a Title 5 system can discharge in those areas. Specifically, Title 5 designated Nitrogen Sensitive Areas to protect drinking water under 310 CMR 15.214 and 15.215.

The recent revisions to Title 5 do not change those existing drinking water protections. They will, however, regulate a new type of Nitrogen Sensitive Area, summarized below. The amended regulations are intended to reduce nitrogen loads that impact coastal waters.

Nitrogen Sensitive Areas

The new regulations amend the existing Title 5 regulations to reduce nitrogen from Title 5 systems in newly designated “Nitrogen Sensitive Areas” unless the community is exempt from that requirement because it files a Notice of Intent (to secure a Watershed Permit), an application for a Watershed Permit, or a De Minimis Nitrogen Load Exemption.

Automatically designated as Nitrogen Sensitive Areas are 30 watersheds on Cape Cod with nitrogen levels above those listed in the MassDEP water quality standards as areas where the discharge of nitrogen through septic systems would be detrimental to the environment or public health. Here is an online tool which MassDEP has created to find out which areas are so designated as of July 7, 2023. View Nitrogen Sensitive Area Tool >>

Watersheds which are designated in the future as Nitrogen Sensitive Areas will be subject to the same Title 5 requirements after the initial community application period expires.

A Watershed Permit when issued will be valid for 20 years. It will establish performance standards, authorized activities, and a management framework to achieve nutrient load reductions that are necessary to meet specific water and habitat quality goals in order to comply with water quality standards set for the waterbody. Obtaining a Watershed Permit will exempt a watershed from a mandatory Title 5 five-year upgrade of septic systems and allow the community to take different and more flexible approaches to address nitrogen concerns.

On the other hand, rather than a Notice of Intent or Watershed Permit, communities may apply for a De Minimis Nitrogen Load Exemption if they meet the eligibility requirements set forth in 314 CMR 21.12.

Septic System Upgrades

Septic system owners within Nitrogen Sensitive Areas already designated in these regulations will need to add nitrogen removal to their Title 5 systems within seven years from when these regulations took effect.

This bears repeating. The upgrade requirement starts in two years, and owners have five years from then to upgrade their septic systems (a total of seven years from July 7, 2023).

For septic systems within Nitrogen Sensitive Areas which are designated in the future, the same timeline applies with the seven years beginning to run on the date of designation.


Now is the time for homeowners, businesses, industry, developers, builders, engineers, consultants, lenders, investors, brokers, real estate attorneys, and public and private facilities on septic systems to get acquainted with these new regulations. Learn whether your local government intends to submit a Notice of Intent, file an application for a Watershed Permit, or seek a De Minimis Nitrogen Load Exemption. These are the three municipal options to suspend the septic system upgrade deadlines.

Rather than wait to find out what the towns will do, where your properties are located, or whether your properties become located within a later-designated Nitrogen Sensitive Area, you could plan for and make arrangements to upgrade, replace or install the nitrogen-treatment type of systems that are required under the amended Title 5. Or you could learn about and maybe facilitate connections to available or planned public or private sewerage systems (POTW).

It is better to anticipate environmental requirements this way and plan ahead for the physical, financial, engineering and construction impacts. This is especially so if you wish your properties to remain productive, enhance their values, stay out of trouble, be marketable, and avoid the extra costs and hassles of trying to comply in a rush.

Visit the MassDEP website for more information at:
Septic Systems (Title 5) >>
Watershed Permit Regulations >>
Community Septic Management Loan Program >>


Read 1458 times Last modified onTuesday, 11 July 2023 11:52
Caroline E. Smith, Esq.

CAROLINE SMITH, ESQ. is an Associate Attorney at McGregor Legere & Stevens PC.  She is a member of the Massachusetts and Boston Bar Associations and the Real Estate Bar Association for Massachusetts. She is active with several environmental, land use, alumnae, and law related organizations.

Ms. Smith is a graduate of Saint Michael’s College (VT) and New England Law | Boston. She participated in the Justice Sandra Day O’Connor Honors Program at New England Law | Boston and graduated magna cum laude.

While in law school, Ms. Smith joined the New England Law Review as an associate member during her 2L year and then served as Business Managing Editor during her 3L year. She also participated in the Environmental Law Society. 

Also while in law school, Ms. Smith served as judicial intern for the Honorable Judge Casper at the United States District Court for the District of Massachusetts; judicial intern for the Honorable Justice Gaziano at the Massachusetts Supreme Judicial Court; 3:03 Certified Student Practitioner at the New England Law | Boston Clinical Law Office; and intern at the Massachusetts Division of Administrative Law Appeals.

Ms. Smith has authored papers and publications on contractual remedies, sovereign immunity, and attorneys’ fees on civil litigation. She is fluent in using Westlaw, LexisNexis, HeinOnline, Bloomberg Law, and Relativity.

Prior to attending law school, Ms. Smith worked as a paralegal at Campbell Conroy & O’Neil, P.C. in Boston, MA.

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