Work Together or Fend for Yourself: New Rules Aim to Reduce Nitrogen from Cape Cod’s Septic Systems and Watersheds

New rules issued by MassDEP offer Cape Codders a choice for controlling nitrogen pollution. The problem is well-understood. When too much discharged nitrogen reaches coastal waters, excess plant and algae growth replaces desirable ecosystems, such as eelgrass. Excess nitrogen causes eutrophication, an environmental problem, and an economic problem that harms fishing, shellfishing, recreational opportunities, tourism, and real estate values. The source is primarily septic systems, but fertilizers, agricultural runoff, and stormwater runoff also contribute. As of July 7, 2023, MassDEP’s amendments to 310 CMR 15 (Title 5) and the new 310 CMR 21 (Watershed Permit) force a choice: either towns commit to long-term plans, or individual property owners will face expensive upgrades.

“Title 5” rules govern the construction and maintenance of septic systems and the transport of septic system waste. Title 5 regulations were previously limited to ensuring that septic systems did not jeopardize nearby drinking water sources. The amended Title 5 regulations will also protect “natural resource areas” from nitrogen overloading. There are two options for compliance. Communities may (alone or in conjunction with neighbors) obtain Watershed Permits that detail long-term plans to improve water quality, or owners of properties with septic systems must upgrade their systems with nitrogen-reducing technology.

MassDEP obtained community and public feedback for the rules with over 45 public meetings and briefed legislators and 32 municipalities prior to publishing draft regulations. Several hundred people attended nine additional public hearings or information sessions held after the draft regulations were published, and over 1,000 written and oral comments were received. While the draft regulations included off-Cape coastal towns, the final regulations focus only on Cape Cod. Cape Cod towns were already working together based on requirements of the Federal Clean Water Act, Section 208, which required regional wastewater management plans.

Certain watersheds draining to estuaries (tidal areas near river mouths) and embayments (recesses in coastlines), where freshwater rivers and streams meet saltwater seas, are designated in the new rules as “Nitrogen Sensitive Areas.” Healthy estuaries and embayments provide biologically productive habitat, recreational resources, flood storage, and buffers between land and ocean. The key criterion for NSA designation is the Total Maximum Daily Load (TMDL), a scientific determination of the maximum amount of a pollutant allowed to enter a water body that enables maintenance of water quality standards, approved by the United States Environmental Protection Agency for nitrogen. Watersheds subject to Section 208 that receive a nitrogen TMDL from EPA after July 7, 2023, will automatically get a NSA designation. MassDEP may designate NSAs without TMDLs, after public notice, public comment, and possibly public hearings in the affected community. Towns with NSAs may obtain “Watershed Permits” that outline long-term plans to restore and protect water quality; these permits offer more flexibility than simply implementing nitrogen-removing septic systems. If a town does not apply for a Watershed Permit within two years of NSA designation, owners of septic systems in that town have five more years to incorporate “Best Available Nitrogen Reducing Technology.”

Presently, 30 defined Cape Cod watersheds, flowing toward Nantucket Sound and covering 14 towns, have the NSA designation. Another NSA is slated for the Wellfleet Harbor watershed. Affected watersheds can be viewed here. Provincetown, which benefits from greater water flow around the tip of the Cape and a town sewer system, currently has no “Nitrogen Sensitive Areas.” The four Cape communities under the Pleasant Bay Watershed Permit (which was issued before the new regulations) can rely on the nitrogen reduction and removal solutions outlined in that permit. It incorporates plans to implement traditional wastewater management technologies, such as sewers, and non-traditional strategies, such as shellfish aquaculture and permeable reactive barriers, based on a 40-year design and financing horizon.

Other highlights relating to the new rules include:

• The Department may extend the compliance time limits for “good cause” including insufficient equipment or material supply or contractor unavailability.
• Individual septic systems upgraded within ten years prior to July 7, 2023, with Department-approved nitrogen removing technology systems are exempt from individual upgrade requirements.
• MassDEP reports that installation costs of nitrogen removal technologies for private septic systems range from $17,000 to $36,000. A commenter shared that they received quotes for new systems costing $60,000 to $90,000.
• Nitrogen removal systems have operation and maintenance costs with quarterly or annual monitoring.
• The Community Septic Management Loan Program provides funding using betterment agreements (low-cost loans that become part of a property tax bill). Barnstable County also has a septic loan program.

Relief may be on the way in the form of an increased state tax credit for septic system replacements and upgrades. Governor Maura Healey proposed to double it, and the Senate earlier this month approved tripling it to $18,000 in credits over five years. Later, but with no specific timeline, MassDEP anticipates drafting rules that include the islands and other southeastern coastal Massachusetts communities. With unusually long timeframes required by Watershed Permits and the large number of properties needing upgrades, these rules could be called the full employment act for the environmental consulting and engineering community. For a primer on nitrogen pollution and solutions, visit here.