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Water: Radionuclides Rule

Radionuclides in Drinking Water

Most drinking water sources have very low levels of radioactive contaminants ("radionuclides"), most of which are naturally occurring, although contamination of drinking water sources from human-made nuclear materials can also occur.  Most radioactive contaminants are at levels that are low enough to not be considered a public health concern. At higher levels, long-term exposure to radionuclides in drinking water may cause cancer. In addition, exposure to uranium in drinking water may cause toxic effects to the kidney.

To protect public health, EPA has established drinking water standards for several types of radioactive contaminants combined radium 226/228 (5 pCi/L); beta emitters (4 mrems); gross alpha standard (15 pCi/L); and uranium (30 µg/L).

This web site is designed to provide you with information about radionuclides in drinking water and provide guidance materials to help the states and water systems comply with the standard.

  • Basic Information - Learn more about the sources of radionuclides, health effects and frequently asked questions.
  • Radionuclides Rule - Get updated information on the radionuclides rule, including quick reference guides.  The history of the rule-making is also featured.
  • Compliance Help - If you are a public water system or state, visit this page to get available tools and training information on how to comply with the rule.

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