Glossary of Drinking Water Tests

(Maximum Contaminant Level = 0.010 mg/L)

Arsenic occurs naturally in New Hampshire and other areas of New England. In fact, arsenic was mined commercially in New England during the 1800s. Arsenic also occurs as a result of human activities. Activities that could have left arsenic residual include orchard spraying (pesticide usage) and coal ash disposal. Generally is not possible to predict if will have elevated arsenic. Arsenic has no smell, taste or coloration when dissolved in water, even at higher concentrations. Only water quality testing can determine its presence and concentration in water.

Arsenic has been classified by the EPA as a human carcinogen (cancer causing agent). Long term exposure to arsenic has been linked to cancer, cardiovascular disease, immunological disorders, diabetes and other medical issues. The MCL for arsenic is 0.010 mg/L which became enforceable on all public water systems as of January 2006. The NH DES recommends that at least two tests be conducted before concluding the well’s arsenic concentration, as well water quality can change due to many factors.

Download our Fact Sheet on Arsenic