Cesspools and failing septic systems must be replaced to meet designated T1 or T2 standard based on site conditions, location in critical resource area, and location in wetland buffer by December 31, 2005. Septic Systems Tank improvements in T1 treatment zones are designed to enhance primary treatment. The large majority of systems will need to install these low-cost, low tech improvements. T2 performance standards are designed to safeguard the quality of individual wells, to ensure system longevity on difficult sites, and to protect the future qualtiy of public drinking water supplies and shellfishing habitat from cumulative effects of onsite systems. A Treatment level map was created to identify critical resource areas and approximate location of treatment zones based on general soil types.
Site investigation is essential to determine the requried treatment level.
Peckham, Sands and Fresh Ponds. In other wellhead areas - E. Searles Ball, Ministers Lot, and Harbor area and Great Salt Pond watershed ONLY where site vulnerability is high to extreme. This includes water table less than 4 feet or where water table is less than 6 feet and has either percolation rate slower than 40 minutes per inch, restrictive permeability less than 0.2 inches per hour, or excessively rapid permeability. Additional restricitons apply in wetland buffers. Requriements for T2 treatment are less restricitve outside of critical areas.