ISDS 



Dartmouth Board of Health regulations and policy relating to ISDS installation and 

 maintenance reference the overlay and aquifer protection districts, are quite rigorous, and 

 have been appUed successfully since the mid- 1970's. The Dartmouth ISDS regulations are 

 reproduced in Appendix 2.1. 



Falmouth, Massachusetts 



Falmouth aquifer protection by-laws prohibit a wide range of site uses in designated areas, 

 permit certains uses under specified conditions, and establish strict design requirements to 

 control non-point contamination of the aquifer. For permitted uses, applicants must 

 demonstrate that all proposed uses will not degrade current or future public water supplies. 

 Development-induced runoff loadings must be calculated, and are used as input to a 

 mathematical drainage-impact formula which predicts loading to the aquifer. Applicants 

 must adjust design specifications to stay within impact limitations. 



Falmouth requires that, where feasible, ISDS be located outside the aquifer protection 

 district Sewage loadings are specifically limited by lot area to 7.5 gpd per 1000 square 

 feet of lot area. 



Plymouth, Massachusetts 



Plymouth uses a zoning overlay district to control development of areas having poorly 

 drained soils, barrier beaches, and tidal flats. Strict conditions are attached to permits 

 issued. Regulations prohibit filling of wedand to obtain sufficient area for leachfield 

 construction, or to raise the leaching area. "The filling of land in order to provide the four 

 foot minimum distance between the bottom of the disposal system and the maximum 

 groundwater elevation is not considered an acceptable practice, and such lands are 

 considered as not suitable from a sanitary point of view for human habitation." 



Idaho 



Panhandle Health District 



A growth management approach developed by the Panhandle Health District, a multi- 

 county health district in northern Idaho, guides implementation of policies and programs 

 via the use of contractual agreements. It is based on the strong local perception that future 

 growth should pay for itself. 



Although the mechanism was developed to control ISDS contamination of the sole 

 source aqmfer shared by Kootenai County and Spokane, Washington, it could be applied 

 to several other non-point categories of concern in the Narragansett Bay watershed as well, 

 including release of VOCs into aquifers, retrofitting of dry wells for control of storm water 

 contamination of groundwater, implementation of underground storage tank controls, and 

 establishment of hazardous materials handling controls. 



On the basis of results of an in-depth 16 month private well monitoring program which 

 revealed high nitrate contamination levels, the PHD developed general aquifer protection 

 regulations, drawing on its dual authorities to protect pubhc water supplies and to issue 

 ISDS construction permits. The regulations were design to limit dense development to 

 areas which could be effectively sewered, and to ensure that, in unsewered areas, lot sizes 



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