The Carlisle Mosquito Online

Friday, October 17, 2008

New septic regulations allow easier living space expansion

At the Board of Health meeting October 2, a home at 883 East Street received approval to expand living space under new town regulations reducing the septic capacity required for additional bedrooms. The application to allow finishing of a master bedroom and den was approved by the four members in attendance, Chair Jeff Brem, Chris Deignan, Michael Holland and Bill Risso. Leslie Cahill was not present. A deed restriction disallowing future addition of a garbage grinder was part of the application.

Bill Risso, reached at home, noted the capacity requirement change was based on “a lot of research” and the board “discussed it for a year.” Regulations drawn up 15 to 20 years ago were found to be too conservative, as the addition of bedrooms did not add septic demand on a linear scale. In addition, over-large septic systems can endanger the biomass necessary to decompose materials as there may be insufficient nutrients. The complete regulations can be found on the town website, ∆

Carlisle New Soil Absorption System Design Flow Requirements

Bedrooms GPD* Required GPD Required GPD Required

per Bedroom w/o Garbage Grinder w/ Garbage Grinder

Three 165 495 495

Four 150 600 660

Five 125 625 825

Six 110 660 990

>Six** 110 110 per bedroom 165 per bedroom

The minimum design flow requirement is 495 GPD.

*GPD is Gallons per day

**To a maximum 2000 GPD

© 2008 The Carlisle Mosquito