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Natural Radionuclides in Public Drinking Water

  • Public drinking water plants test for contaminants and filter them out, including radionuclides.
  • EPA sets limits for radionuclides in public drinking water through the Safe Drinking Water Act. Local water suppliers must follow these limits.

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About Natural Radionuclides in Public Drinking Water

Although the water treatment process varies slightly at each facility, the basic process is the same.
Source: Scottsdale, AZ

Water treatment plants take precautions to protect drinking water before supplying it to the public. 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.

Many of the contaminants found in public drinking water sources occur naturally. For example, the minerals radium and uranium are found in small amounts in almost all rocks, soil and water. Radon, a radioactive gas, can be another natural contaminant in water. It comes from the breakdown of radium in soils, rocks and water. If it were not removed, radon in water could be released from into the air as you shower or use water for other household tasks like washing dishes or doing laundry.

However, a much more common source of radon in the home is in the air itself. Radon moves up from the ground into buildings through openings in floors or walls that are in contact with the ground. Radon can accumulate in buildings over time and may pose a health hazard. Any home or building may have high levels of radon, including new and old homes, well-sealed and drafty homes, and homes with or without basements.

Drinking water suppliers prevent water sources from becoming contaminated by:

  • Identifying the path that water travels to reach the drinking water intake and determining areas where drinking water could become contaminated.
  • Participating in voluntary programs that help keep contaminants out of drinking water. These programs could help educate the public or help businesses learn how to properly dispose of wastes that could contaminate water.
  • Preparing for emergencies, such as a flood or spill that could threaten the drinking water supply.

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Rules and Guidance

U.S. Environmental Protection Agency (EPA)

Under the Safe Drinking Water Act, EPA sets limits for radionuclides in public drinking water. Local water suppliers must follow these limits. They are also required to inform citizens about the level of radon and other radionuclides in their water. This is usually done through annual drinking water reports. EPA provides guidance to drinking water treatment plants and state regulatory agencies on meeting the limits.

The States

Most states have set drinking water standards that meet the requirements set by EPA under the Safe Drinking Water Act. The states enforce those standards and set monitoring programs. Find your state radiation program contact exit EPA.

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What you can do

Stay informed. Public water systems follow laws that protect the public from radiation in drinking water. Stay informed by reading your public water system's annual report card to see how well the water system in your area meets EPA's contaminant limits for drinking water.

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Where to learn more

Public Drinking Water Systems Programs
U.S. Environmental Protection Agency, Ground Water & Drinking Water
This webpage provides information and links to additional resources regarding drinking water safety standards.
Summary of the Clean Water Act
U.S. Environmental Protection Agency 
This webpage shows a summary of the Clean Water Act and provides links to information regarding the history and EPA's role in enforcement.
Drinking Water Contaminants: Radionuclides
U.S. Environmental Protection Agency
This webpage shows basic information about radionuclides in drinking water, including possible health risks of radionuclides and other contaminants.
A Regulators Guide to the Management of Radioactive Residuals from Drinking Water Treatment Technologies (PDF) (81pp, 559Kb)
U.S. Environmental Protection Agency 
This document provides insight into the various technologies and practices that are used to manage radioactive drinking water wastes.
Safe Drinking Water Act
U.S. Environmental Protection Agency 
This page contains links to basic information and fact sheets on the Safe Drinking Water Act.
State Radiation Programs exit EPA
Conference of Radiation Control Program Directors.
This page provides links to contacts for and information about state radiation protection programs.
U.S. Environmental Protection Agency
This webpage provides information about radon and shares answers to frequently asked radon questions, including what you can do about high radon levels in your home.  
Welcome to the National Radon Safety Board exit EPA
National Radon Safety Board
This webpage links to radon-related websites, including information on radon detecting services and devices.

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