This is a proposed updated Action Plan in the Buzzards Bay CCMP 2024 Update.

Managing Onsite Wastewater Disposal Systems

Problem

While there have been efforts to sewer more areas in the Buzzards Bay watershed, sewering efforts have been gradual in many areas, and homes in the less densely developed areas will continue to use onsite wastewater disposal systems (“septic systems”) for years to come. The widespread use of conventional septic systems poses a threat to many embayments and freshwater ponds in the Buzzards Bay watershed. Failed and inadequate septic systems also remain a source of pathogens contributing to water quality impairments. Even properly designed and operated conventional onsite septic systems are important source of nitrogen pollution to coastal watersheds. The 1996 updates to the states sanitary code (Title 5) required both new standards and the inspection and replacement of inadequate systems at the time of property transfer. These regulations have eliminated many problem systems. However, many properties have not changed hands since 1995, and many inadequate systems remain in place. Moreover, the 1995 did not address nitrogen loading to coastal embayments. In July 2023, MassDEP amended Title 5 to reduce nitrogen loads to coastal estuaries and embayments on Cape Cod. Under the revised regulations, for nitrogen sensitive areas, municipalities have the option of implementing a local watershed plan to comply with nitrogen TMDLs, or the MassDEP will require the upgrade of all onsite wastewater systems to Best Available Nitrogen Reducing Technology. Both strategies pose financial and administrative challenges to municipal government that must be addressed.

The nutrient impacts of septic systems are also addressed in Action Plan 1 Managing Nitrogen Sensitive Embayments.

Goals and Objectives

Changes: Some objectives were re-worded improve clarity and readability. Four new objectives were added to clarify actions needed to meet stated goals.

Goal 5.1. Prevent public health threats and environmental degradation from on-site wastewater disposal systems.
Objective 5.1. Enforce the provisions contained in Title 5 regulations such as siting and design, inspection and upgrades, training, maintenance, mapping, and mitigation of nitrogen sensitive areas.
Objective 5.2. Support local watershed plans and encourage boards of health to adopt local regulations to ensure and/or improve environmental and public health protection to meet local needs.
Objective 5.3. Improve management and oversight by municipalities of onsite wastewater disposal systems.
Objective 5.4. In areas where advanced nutrient removal is required, evaluate and compare the benefits of centralized sewering, community scale satellite treatment systems, and individual alternative systems.
Objective 5.5. Encourage towns to track septic tank pumping frequencies and to remind homeowners to pump their septic tanks at appropriate frequencies. (New)
Objective 5.6. Encourage and promote ongoing research on new alternative onsite wastewater disposal systems that more effectively remove nutrients. (New)
Objective 5.7. In areas around freshwater ponds, where excess phosphorus is causing reductions in surface water quality, promote strategies and technologies to reduce the phosphorus loading to the pond. (New)
Objective 5.8. Encourage research on innovative strategies to remove or sequester excessive phosphorus loading from eutrophic freshwater pond sediments. (New)