Arsenic is a naturally occurring chemical element that widely exists in the Earth’s crust. Arsenic is found in water, air and soil and levels vary depending on the environment.

Arsenic levels tend to be higher in groundwater sources, such as wells, than from surface sources, such as lakes or reservoirs.

The maximum level of inorganic arsenic permitted in U.S. drinking water is 10 parts per billion (ppb).

Download the arsenic fact sheet