Important Updates to State Septic Regulations

On July 7, 2023, new state regulations governing the design, construction, repair and upgrade of on-site septic systems went into effect.  These regulations focus on Cape Cod watersheds, and are intended to address nitrogen pollution and other water-quality issues across the South Coast.  

What does this mean for the average Mashpee homeowner?

Under the new state regulations, beginning July 8, 2024, all new construction must include Best Available Nitrogen Reducing Technology, as defined in the regulations.  July 7, 2025 begins a five-year mandatory upgrade to Best Available Nitrogen Reducing Technology for any remaining conventional or non-conforming septic systems throughout the Town.  These enhanced treatment requirements for both existing systems and new construction will be suspended if the Town files a Notice of Intent or a Watershed Permit application with the state before July 7, 2025.  

A Watershed Permit is a 20-year agreement that will allow the Town to delay these wide-scale septic system upgrades.  Mashpee's Watershed Permit application, which is currently being drafted, will outline the Town's Nitrogen Management Plan to meet the approved TMDLs, by designating areas that will be connected to centralized sewer, along with those areas where on-site systems will require enhanced treatment.  TMDL stands for "Total Maximum Daily Load", which is a calculation of the maximum amount of a pollutant that a waterbody can accept and still meet the state's water quality standards for public health and healthy ecosystems.

Please direct any questions regarding the status of the Town's Watershed Permit application to the Office of the Town Manager at 508-539-1401.

Mashpee has a local Board of Health regulation which has similar enhanced treatment requirements for any system that is within 300' of surface water, at four thresholds: 1) new construction; 2) failure of the existing on-site system; 3) proposed increase in flow (adding bedrooms); 4) tear down and rebuild of the existing dwelling.  The Board of Health also has a regulation which requires enhanced treatment for any system with a design flow in excess of 600 gallons per day (i.e. more than 5 bedrooms).  These regulations will remain in effect unless amended or rescinded, regardless of whether the Town applies for a Watershed Permit:

Please direct any questions regarding these Board of Health regulations to the Mashpee Health Department at 508-539-1426.