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Water: Basic Information about Regulated Drinking Water Contaminants

Basic Information about Regulated Drinking Water Contaminants and Indicators

Drinking water, including bottled water, may reasonably be expected to contain at least small amounts of some contaminants. The presence of contaminants does not necessarily indicate that water poses a health risk. EPA sets standards for approximately 90 contaminants and indicators in drinking water. The presence of indicators at a level outside of specified limits may reflect a problem in the treatment process or in the integrity of the distribution system.

The fact sheets posted on this page update fact sheets published previously, and add new ones. For historical purposes, the original versions are available in PDF format on this page: Drinking Water Contaminants.

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