| Arsenic in Drinking Water |
| The Safe Drinking Water Act of 1974 required the Environmental Protection Agency (EPA) to revise the then-existing standard for arsenic in drinking water. The new standard protects against possible adverse health effects from exposure to arsenic in drinking water and reflects the statutory evaluation of whether the costs are justified by the benefits. The process for revising the standard is complex, and the EPA had to consider a range of scientific, economic, and programmatic factors. In 1975, the EPA established the current maximum contaminant level (MCL) for arsenic in drinking water at 50 micrograms per liter (µg/L), or parts per billion (ppb). This arsenic in drinking water standard is based on the drinking water standard set by the Public Health Service in 1943. Home Page | FAQs | Glossary | Contact Us |