County level domestic well population with arsenic greater than 10 micrograms per liter based on probability estimates for the conterminous U.S.
Approximately 43 million people (about 14 percent of the U.S. population) rely on domestic wells as their source of drinking water. Unlike community water systems, which are regulated by the Safe Drinking Water Act, there is no comprehensive national program to ensure that the water is tested to ensure that is it safe …