ENSURING DOMESTIC WELL WATER QUALITY IN THE OSSIPEE AQUIFER REGION OF CENTRAL NEW HAMPSHIRE

The Ossipee Aquifer, located in East Central New Hampshire, is the largest stratified drift aquifer in the state. The vast majority (>70%) of residents in this area rely on private wells for their drinking water. While public water systems are required to monitor water quality on a regular basis, there are no such regulations for domestic wells. The lack of regulations, together with the high cost of analyses, means that most people in the region are unaware of the quality of their water supply.

To address this issue, the Green Mountain Conservation Group (GMCG), a nonprofit environmental organization, partnered with Smith College’s Department of Geosciences to test over 200 private wells in 2009, 2016 and 2019. These studies were conducted to establish baseline water quality data for the watershed. Well water samples were analyzed for all major cations, anions and silica, together with a suite of trace metals and stable isotopes. In addition, samples from the 2016 campaign were also analyzed for VOC’s. The results have shown that wells in the region are susceptible to both anthropogenic and natural sources of contamination. Road salt has had the largest impact, with an increasing number of wells impacted each year. Approximately 30% of the wells sampled (88) in 2019 showed road salt impacts with Cl concentrations ranging from <1 mg/L to over 500mg/L and an average of 44 mg/L. Natural contaminants are associated with the regions bedrock geology. Although many wells in southeastern NH have high concentrations of naturally occurring arsenic, none of the wells in the Ossipee region had arsenic concentrations in excess of 4 ppb. However, many of the wells in this area have corrosive water and are therefore susceptible to high lead and copper leached from water pipes. In addition, uranium concentrations exceeded the 30ppb MCL in almost 10% of the 88 samples analyzed in 2019.

This groundwater research informs the educational programs GMCG hosts to alert homeowners of potential contamination sources and encourage water testing. In addition, GMCG established the Ossipee Aquifer Advisory Committee with members from the 7 towns that lie within the Ossipee Aquifer. This group advises towns on aquifer issues and Best Management Practices. Through these efforts, it is hoped that local residents can be protected from groundwater contamination.