[HISTORY: Section 3 of the Plainville Board of Health Regulations. Amendments noted where applicable.]
These rules and regulations have been adopted to protect the water supplies of the residents of Plainville from excessive contamination of nitrate and other harmful chemicals resulting from the subsurface discharge of wastewater effluent. Nitrate contamination of drinking water is a serious public health problem. Nitrate also may serve as an indicator of other groundwater degradation associated with the use of household and industrial chemicals, pesticides, solvents, and other toxic substances. Therefore, the presence of those other substances may be presumed to be present also, when more than natural background levels of nitrate occur. Subsurface wastewater disposal, without nitrogen removal, is a major source of nitrate-nitrogen loading in the groundwater and surface waters.
These rules and regulations shall also protect surface water and groundwater from excessive nitrate-nitrogen and other nutrient loading and will retard the process of eutrophication of the lakes and ponds.
By requiring sufficient dilution of nitrates as well as these other by-products of human activity, they may be decreased to a level which does not constitute a threat to the public health. Adequate land area surrounding a subsurface sewage disposal system will result in the dilution of the subsurface sewage discharge to levels of contaminants that will not constitute a threat to public or environmental health.
The Town of Plainville derives its water supply from groundwater. The groundwater supplies both the public water system and individual on-site wells. The groundwater of the Town of Plainville, and the surface waters which contribute to the groundwater, constitute its water supply. Therefore, this regulation shall apply to any subsurface wastewater disposal system located within the zone of contribution of a public water supply well, located in an area of private well supplies, located within the watershed of Turnpike Lake, Mirimichi Lake, or any other pond in the Town of Plainville, or within the watershed of any stream which drains into said lakes and ponds.
This regulation shall not apply for the repair of existing septic systems where there is no increase in wastewater flow or there is no change of use. It shall not apply where there is connection to Town sewer.
The applicant for construction of any subsurface wastewater system in the Town, except for repairs of existing systems which have failed and are not being enlarged to provide for additional building construction or use, shall submit a groundwater impact report (GIR) to the Board of Health. In the case of a subdivision, the GIR shall be submitted at the time of submittal of the preliminary plan. In case of lots not requiring approval as a subdivision, the GIR shall be submitted at the time of application for a disposal works construction permit.
The GIR shall be based on the following methodology for determination of nitrate loading which is based on procedures that have been accepted by and have been adopted and used by governmental planning agencies, enforcement agencies, and the U.S. Geological Survey. The GIR shall determine whether or not the proposed project will cause unacceptable groundwater quality at the project boundary limits for the proposed use, based on the expected nitrate-nitrogen loading. The calculations shall follow the guidelines contained herein, using data which is appropriate for the Town of Plainville.
The maximum allowable calculated concentration of nitrate-nitrogen within each project boundary shall be five milligrams per liter in Zone II of the public water supply and areas of private on-site well water supplies. It shall be 7 1/2 milligrams per liter in all other areas within the Town.