Module 3 Footnotes
1 Calculated from a decay rate table provided in Appendix 1 of Septic Tank Siting to Minimize the Contamination of Ground Water by Microorganisms from Office of Groundwater Protection, Washington, D.C., June, 1987.
Section 15.214: Nitrogen Loading Limitations
(1) No system serving new construction in Nitrogen Sensitive Areas designated in 310 CMR 15.215 shall be designed to receive or shall receive more than 440 gallons of design flow per acre except as set forth at 310 CMR 15.216 (aggregate flows) or 15.217 (enhanced nitrogen removal).
(2) No system serving new construction in areas where the use of both on-site systems and drinking water wells is proposed to serve the facility shall be designed to receive or shall receive more than 440 gallons of design flow per day per acre from residential uses except as set forth at 310 CMR 15.216 (aggregate flows) or 15.217 (enhanced nitrogen removal).
3 Actually leaching pits and deeper leaching structures are not prohibited in the code, however since only two feet of the sidewall area can be used for credit, they have essentially lost favor with most engineers and installers.
4 Note: Some old copies of the revised code contain an error in these setback distances.
5 The Natural Heritage and Endangered Species Program, administered by The Massachusetts Department of Wildlife creates yearly updated maps for each area that depict vernal pools. Conservation Commissions maintain the maps in their offices for public viewing. The program can be contacted at Rte 135, Westborough, MA 01581.
6 Section 15.211[2} states "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".
7 Section 15.405: Contents of Local Upgrade Approval (1)(h) Reduction of system location setbacks from water supply lines, private water supply wells (but not within 50 feet of the well),.....
8 There is a minimum Zone 1 of 100 ft.
9 15.212. Depth to Groundwater The minimum vertical separation distance of the bottom of the stone underlying the soil absorption system above the high ground-water elevation shall be (a) four feet in soils with a recorded percolation rate of more than two minutes per inch; (b) five feet in soils with a recorded percolation rate of two minutes or less per inch.
10 (g) any portion of the soil absorption system that is within the velocity zone or regulatory floodway is a leaching bed or trench system or any other system constructed in accordance with the wetlands protection act and 310 CMR 10.00.