Arsenic in Private Wells in Connecticut (IMAGE) U.S. Geological Survey Caption 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. Credit USGS Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.