Part 1 of a 2-Part Series on the Validity of the CLF Lawsuit
In June 2021, the Conservation Law Foundation (CLF) filed suit against the Mass. Department of Environmental Protection (DEP) and the Towns of Barnstable and Mashpee, charging them with violating the state’s Title 5 regulations, specifically targeting the passages on limiting nutrient discharge in “Nitrogen Sensitive Areas.” The CLF suit alleges that state and local government leaders have “known for decades that nitrogen and phosphorus were contaminating Cape waterways yet continued to permit conventional septic systems without regard to the danger.” [Source: Cape Cod Times]

As homeowners on Shoestring Bay, a beautiful but dangerously nutrient-compromised embayment shared by Cotuit [Town of Barnstable] and Mashpee, we got to thinking: Is our property located in an official “Nitrogen Sensitive Area” [NSA]? A good question without an easy answer. In the original 1995 Title 5 regs., the DEP unhelpfully advised that it was “the duty of the [home]owner” to figure out if their property was in an endangered area. And to help homeowners “figure it out” the DEP committed to mapping designated NSA’s “based on scientific evaluations of the affected water body and adopted through parallel public processes.” But good luck finding any such mapping, tables, or even proposals for defining areas as “Nitrogen Sensitive” on either the Commonwealth of Massachusetts or the DEP web sites.
The closest Title 5 regulations get to defining a Nitrogen Sensitive Area is:
An area of land and/or natural resource area so designated by the Department in accordance with 310 CMR 15.215.
In other words, it is what we say it is, but we’re not saying what it is. No one really knows the definition of NSA’s under DEP’s circular regulations. It seems like the only way to fix this confusing mess was to sue the DEP. Enter the CLF!
Question: How Should We Define “Nitrogen Sensitive Area”?
Thankfully, DEP is in the midst of re-defining Nitrogen Sensitive Areas. In a draft revision to 310 CMR 15.215, the proposed language we could find online defines the areas as:
An area that is in close proximity to any nutrient compromised body of water…one that
Proposed MA-DEP definition of Nitrogen Sensitive Area
contains an abundance of Nitrogen compounds exceeding its clearly defined total maximum daily load (TMDL) of Nitrogen.
Unfortunately, the term “close proximity” is awfully vague; we suggest that DEP adopt the language from the Town of Bourne, MA—within 150 feet of a Nitrogen Sensitive Area.
So, yes, many homes along Shoestring Bay and the Three Bays area are clearly in close proximity to an NSA and many likely exceed Title 5’s acceptable flow rates for effluent. Barnstable’s one-size-fits-almost-all solution is sewering. But when the sewer arrives in Cotuit in 20+ years (measured from 2019) per the Town of Barnstable’s CWMP, some of these Bays will likely be near death, or become a toxic, putrid mud puddle. Imagine what that will do to tourism, public health, and property values!
Next Question: Is Your Title 5 System Legal?
Without getting into the weeds on the math to determine if your Title 5 septic system within an NSA is legal, the short answer is: probably not.

- The proposed DEP standard for discharge of nitrogen into the groundwater within Nitrogen Sensitive Areas is less than 10 PPM of Nitrogen (1 ppm = approximately 1 mg/L)
- Your Title 5 system discharges between 80 and 120 MG/L of Nitrogen into the groundwater. Because Title 5 systems remove NONE of the Nitrogen, your septic system is emitting 8 to 10 times the maximum proposed standard!
Who’s To Blame for Your Illegal Septic System?

Not You! The fault lies with those on whom property owners rely—the Town Health Departments and Civil Engineers that approved your Title 5 system. That’s because your Town doesn’t calculate your home’s theoretical effluent flow rate on the amount of water you use [which would be the logical way.] Instead, the Town calculates flow rate based on the number of bedrooms! Never mind that a three-bedroom house could have 8-10 people showering every day! Not to mention all the dish washing, toilet use, and clothes washing. The Towns keep approving waterfront McMansions without regard to a home’s actual water use—and that’s wrong.
…To be continued. Next Up: How do we fix this mess?