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Natural Radionuclides in Public Drinking Water

Radiation Facts
  • Public drinking water systems test and filter out contaminants, including radionuclides.
  • The EPA sets limits, called Maximum Contaminant Levels (MCLs), for radionuclides in public drinking water under the Safe Drinking Water Act.

Public drinking water systems in the United States must ensure that the water they provide to their customers meet all federal, state, and local drinking water standards. Natural radionuclides are a potential hazard.

On this page:

  • About Natural Radionuclides in Public Drinking Water
  • What you can do
  • Where to learn more

About Natural Radionuclides in Public Drinking Water


Public drinking water suppliers make sure that the water they deliver to the public is safe for consumption. They regularly test the water and use filters or other methods to remove chemicals and natural radionuclides that can get into water from the soil.

Flocculation tanks. Clicking on this image links to a larger version of the image.
This picture shows a large red building behind a large rectangular pond of water, called a flocculation tank. Flocculation tanks are used to help filter drinking water.

Many of the contaminants found in public drinking water sources occur naturally. For example, radioactive radium and uranium are found in small amounts in almost all rock and soil, and can dissolve in water. Radon, a radioactive gas, created through the decay of radium, can also naturally occur in groundwater. If it is not removed, radon in water can be released into the air as you shower or use water for other tasks like washing dishes or doing laundry.

Drinking water suppliers prevent water sources from becoming contaminated by:

Clicking on this image links to a larger version of this image.
Water treatment plant worker. 
  • Identifying the path that water travels to reach the drinking water system to determine areas where drinking water could become contaminated.
  • Preparing for emergencies, such as a flood or spill that could threaten the drinking water supply.
  • Participating in voluntary programs that help keep contaminants out of drinking water. These programs include educating the public and helping businesses understand how to properly dispose of wastes that could contaminate water.

What You Can Do

  • Stay informed. Public water systems follow laws that protect the public from radionuclides in drinking water. Stay informed by reading your public water system's annual Consumer Confidence Reports. These reports will help you understand where your water comes from. In addition, it should explain whether radionuclides have been detected in your water and how the water supplier treats and delivers water to your household.

Where to Learn More

The U.S. Environmental Protection Agency (EPA)

The EPA is the United States’ regulatory agency for clean water. Many resources are available to better understand how different drinking water programs work.

Public Drinking Water Systems Programs
This webpage provides information and links to additional resources regarding drinking water safety standards.

Summary of the Clean Water Act
This webpage shows the history and a summary of the Clean Water Act (CWA) and provides links to information regarding the EPA’s role in CWA enforcement.

Drinking Water Contaminants: Radionuclides
This webpage shows basic information about contaminants in drinking water, including possible health risks of radionuclides.

Safe Drinking Water Act
This webpage contains links to basic information and fact sheets on the Safe Drinking Water Act.

A Regulators Guide to the Management of Radioactive Residuals from Drinking Water Treatment Technologies 
This document provides insight into the various technologies and practices that are used to manage radioactive drinking water wastes.

Radon
This webpage provides information about radon and provides answers to frequently asked questions about radon, including what you can do about high radon levels in your home.

The Conference of Radiation Control Program Directors (CRCPD)

CRCPD is a nonprofit non-governmental professional organization dedicated to radiation protection. 

State Radiation Protection Programs 
This webpage provides links and contact information for each state's Radiation Control Program office.

The National Radon Safety Board (NRSB)

The NRSB certification program offers independent certification, accreditation, and approval for various categories of radon service providers.

Welcome to the National Radon Safety Board 
This webpage links to radon-related websites, including information on radon detecting services and devices.

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Last updated on May 8, 2023
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