Arsenic in Public Water and Health

arsenic in public water

Arsenic is a toxic chemical element that is found naturally in the Earth's crust in soil, rocks, and minerals. The levels of arsenic found in drinking water systems and private water supplies across the United States vary widely. The maximum contaminant level (MCL) for Arsenic is 10 mcg/L.

Exposure and Risk

The majority of health risks from arsenic in the United States are from long term exposures. Although short-term exposures to high doses may cause adverse effects in people, a high dose of arsenic is about a thousand times higher than the drinking water standard. Arsenic exposures do not occur from EPA-regulated public water supplies in the United States that comply with the arsenic MCL.

Possible health effects include:

  • thickening and discoloration of the skin
  • stomach pain
  • nausea
  • vomiting
  • diarrhea
  • liver effects
  • cardiovascular (heart) effects
  • pulmonary (lung) effects
  • immunological (ability to fight infections) effects
  • neurological (brain) effects such as numbness and partial paralysis
  • reproductive effects
  • endocrine effects such as diabetes and
  • cancer
    • bladder
    • lungs
    • skin
    • kidney
    • nasal passages
    • liver and
    • prostate


Public Water Systems are already being tested for arsenic. If you think your drinking water is contaminated, call your water supplier or state drinking water program. You can locate these agencies or find information on drinking water in general from EPA's Safe Drinking Water Hotline at (800) 426-4791.

In Iowa, if you use a private well, you can contact a local county sanitarian and have your water tested for arsenic. Otherwise, contact an environmental laboratory in your area and have your water tested for arsenic for a small fee.