Arsenic in Private Wells in Connecticut

The colors on this map identify the estimated percentage of private wells in Connecticut with water containing arsenic concentrations greater than 10 micrograms per liter, the U.S. Environmental Protection Agency’s maximum contaminant level for arsenic in drinking water supplies. These percentages were determined based on an analysis of water samples from more than 2,000 private wells in the state as well as underlying geology, with bedrock types indicative of arsenic concentrations in groundwater. The black symbols identify arsenic concentrations in water from sampled wells. White areas on the map, representing 1.9% of the state, indicate geologic units from which no arsenic samples are available. Well locations are approximate.