Minimum Setback Distances

(1) All systems must conform to the minimum setback distance for septic tanks, holding tanks, pump chambers, treatment units and soil absorption systems, including reserve area, measured in feet and as set forth below. Where more than one setback applies, all setback requirements shall be satisfied. Septic Tank Soil Absorption System Holding Tank Pump Chamber Treatment Unit Grease Traps Property Line 10[5] 10[5] Cellar or Crawl Space Wall, Swimming Pool (inground), foundation drain Slab Foundation Water Supply Line (pressure) 10[1] 10[1] Surface Waters (except wetlands) Bordering Vegetated Wetland (BVW), Salt Marshes, Inland and Coastal Banks Surface Water Supply - Reservoirs and Impoundments Tributaries to Surface Water Supplies Wetlands bordering Surface Water Supply or Tributary thereto Certified Vernal Pools 100[2] Private Water Supply Well or Suction Line Public Water Supply Well (2) (2) Irrigation Well Open, Surface or Subsurface Drains which discharge to Surface Water Supplies or tributaries thereto Other Open, Surface or Subsurface Drains (excluding foundation drains) which intercept seasonal high groundwater table [3] Other Open, Surface or Subsurface Drains (excluding foundation drains) Leaching Catch Basins & Dry Wells Downhill Slope not applicable 15[4] [1] Disposal facilities shall be at least 18 inches below water supply lines. Wherever sewer lines must cross water supply lines, both pipes shall be constructed of class 150 pressure pipe and shall be pressure tested to assure watertightness. [2] The required setback shall be 50 feet where the applicant has provided hydrogeologic data acceptable to the Approving Authority demonstrating that the location of the soil absorption system is hydraulically downgradient of the vernal pool. Surface topography alone is not determinative. [3] Surface or subsurface drains which will regularly or periodically intercept the seasonal high groundwater table and carry that groundwater away from an area must meet the specified setbacks. [4] The setback distance shall be measured from a naturally-occurring downhill slope which is not steeper than 3:1 (horizontal:vertical). A minimum 15 foot horizontal separation distance shall be provided between the top of the two inch layer of c to ½ inch washed stone above the pipe, or the geotextile material above the pipe or the top of the chamber and the adjacent downhill slope. For a system located in an area with any adjacent naturally occurring downhill slope steeper than 3:1, slope stabilization shall be provided in accordance with best engineering practice which may include construction of a retaining wall designed by a Massachusetts Registered Professional Engineer. [5] Locating a system component or any part thereof beyond a property line of the facility, whether pursuant to an easement or otherwise, requires a variance issued in accordance with 310 CMR 15.410, except that the placement of fill or grading material beyond the property line of the facility, pursuant to an easement or otherwise, shall not require a variance under 310 CMR 15.410. (2) No system shall be constructed within a Zone I of a public water supply well or wellfield. No system shall be upgraded or expanded within a Zone I of a public water supply well or wellfield unless a variance is granted pursuant to 310 CMR 15.410 through 15.415. (3) All setback distances from water bodies shall be measured from the bank of the water body. All setback distances from wetlands shall be measured in accordance with the criteria of the Wetlands Protection Act and 310 CMR 10.00: Wetlands Protection, from the most landward edge of the following features: bordering vegetated wetland as defined in 310 CMR 10.55(2): Definition, Critical Characteristics and Boundary; salt marsh as defined in 310 CMR 10.32(2): Definitions; top of inland bank as defined in 310 CMR 10.54(2): Definition, Critical Characteristics and Boundary; or top of coastal bank as defined in 310 CMR 10.30(2): Definition. In the event of disputes concerning landward boundary of resources subject to the Wetlands Protection Act, the boundary shall be as delineated by the municipal Conservation Commission or the Department in accordance with 310 CMR 10.00: Wetlands Protection, and relevant interpretive guidance documents.