Arsenic

Category: inorganic

Written by WaterFilterMatch Editorial TeamApril 2026

EPA MCL

0.01 mg/L

Status

EPA Regulated

NSF Standard

NSF/ANSI 53 (arsenic V only), NSF/ANSI 58

Health Effects

Skin damage, circulatory system problems, increased risk of skin, bladder, lung, kidney, and liver cancer. Long-term exposure at low levels is associated with cardiovascular disease and diabetes.

Source: EPA National Primary Drinking Water Regulations

Where It Comes From

Natural deposits in rock and soil are the primary source. Also from erosion of natural deposits, runoff from orchards, and runoff from glass and electronics production waste.

Where It's Commonly Found

Groundwater in the western U.S., parts of New England, and the upper Midwest. Private wells in areas with naturally high arsenic geology are particularly at risk.

Approximately 2,200 community water systems have reported arsenic levels above EPA's MCL. An estimated 43 million Americans rely on domestic wells, many in areas with naturally elevated arsenic.