Drinking Water Requirements for States and Public Water Systems

Radionuclides Rule

Rule Summary

The Environmental Protection Agency (EPA) regulates radionuclides in drinking water to protect public health. Radionuclides in water at amounts greater than the drinking water standards may cause health problems.

On December 7, 2000, EPA published the Radionuclides Final Rule. The new rule revised the radionuclides regulation, which had been in effect since 1977. The revisions set new monitoring requirements for community water systems (CWS). This ensured customers receive water meeting maximum contaminant levels (MCL) for radionuclides in drinking water.

For more information on radionuclides in drinking water see the Basic Information page.

Radionuclides Rule Quick Reference Guide

This document provides a simple and straightforward description of the Rule. The guide includes critical deadlines and requirements for PWSs and states, and information on monitoring requirements.

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Rule History

In 2000, EPA revised the radionuclides regulation, which had been in effect since 1977. The revisions set new monitoring provisions for community water systems (CWS). This ensured that all customers of CWSs receive water meeting the maximum contaminant levels (MCL) for radionuclides in drinking water.

EPA also issued a standard for uranium, as required by the Safe Drinking Water Act (SDWA) Amendments of 1986. The current standards are:

  • Combined radium 226/228 of 5 pCi/L;
  • A gross alpha standard for all alphas of 15 pCi/L (not including radon and uranium);
  • A combined standard of 4 mrem/year for beta emitters.

The new MCL for uranium is 30 µg/L.

Federal Register Notices and Documents Pertaining to the Radionuclide Rule History

The Office of Ground Water and Drinking Water's (OGWDW’s) Technical Support Center (TSC) develops analytical methods. These methods help determine the concentrations of chemical and microbial contaminants in drinking water.

EPA issued a final rule with three additional analytical methods. These include inductively coupled plasma mass spectrometry (ICP-MS) technology for compliance determinations of uranium.

In 2004, EPA published minor corrections to the Radionuclides Rule. The correction identified a detection limit for uranium and clarified Rule language.

EPA published a Notice of Data Availability (NODA). The NODA included new information that had become available since the 1991 proposed revisions to the 1976 Radionuclides Rule. The Agency also developed a technical support document to accompany the NODA.

This document provides background information and further describes the analyses discussed in the NODA. The document also contains a Preliminary Health Risk Reduction and Cost Analysis, which presents the analyses of:

  • Projected impacts,
  • Costs,
  • Risk reductions, and
  • Benefits for the uranium National Primary Drinking Water Rule (NPDWR) and the new monitoring requirement for radium-228.

Documents pertaining to the NODA

In 1997, EPA held a public meeting to discuss regulatory issues associated with the 1991 Radionuclides Rule proposal.

In 1991, EPA proposed revisions to the July 9, 1976 Radionuclides Rule. The final Rule published in 2000 finalized this 1991 proposal.


EPA has developed materials to assist drinking water system owners and operators, as well as States and Primacy Agencies. The links on this page will redirect to guidance and tools for the Radionuclide Rule.

Compliance for Public Water Systems

Compliance for Primacy Agencies

Additional Tools and Resources

Radiation Protection Programs

EPA's Agency-wide Radiation Protection Program comprises seven groups of projects and issue-specific programs. You can find descriptions of the programs, as well as program contacts and news, on their webpage. The webpage also includes information on:

  • laws and regulations,
  • publications 
  • and technical materials.

EPA's Radiation Protection Program

Radionuclide Rule Presentations

Question and Answer Fact Sheet

2007 Radionuclide Implementation Workshops