Contaminants in 20 Percent of U.S. Private Wells

More than 20 percent of private domestic wells sampled across the nation contain at least one contaminant at levels of potential health concern. About 43 million people — or 15 percent of the Nation’s population — use drinking water from private wells, which are not regulated by the Federal Safe Drinking Water Act. USGS scientists sampled about 2,100 private wells in 48 states and found that the contaminants most frequently measured at concentrations of potential health concern were inorganic contaminants, including radon and arsenic. These contaminants are mostly derived from the natural geologic materials that make up the aquifers from which well water is drawn. Complete findings are available at http://water.usgs.gov/nawqa/studies/domestic_wells/. For more information, listen to a podcast interview with USGS scientist Leslie DeSimone on this report at Contamination in U.S. Private Wells or contact Leslie at ldesimon@usgs.gov or (508) 490-5023.