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Natural Radionuclides in Private Wells

Radiation Facts

More than 15 million Americans use private wells as their main source of drinking water. Those who use private wells should:

  • Test for radionuclides every three years.
  • Take appropriate steps if radionuclide levels are higher than the EPA’s limits.

About 15% of Americans use private wells as their main source of drinking water. Unlike public water systems, wells are usually not regulated or routinely inspected for radionuclides, though some states and cities do regulate private wells. As a result, well owners are responsible for making sure their drinking water is safe to drink. Well water should be tested on a regular schedule. Each year, well owners should test for contaminants such as bacteria, nitrates and viruses. Every three years, well owners should test for radionuclides.

On this page:
  • About Natural Radionuclides in Private Wells
  • What you can do
  • Where to learn more


About Natural Radionuclides in Private Wells

private well spouting water
Image of water flowing from an outdoor faucet. 
Source: U.S. Centers for Disease Control and Prevention

Uranium is a naturally-occurring radionuclide that decays over time and forms radium. Both elements are naturally present in rocks and soils. Radium breaks down further to form the radioactive gas radon. All three of these elements can dissolve in water, which means they can accumulate in wells. If the soil and rocks surrounding a well have high enough concentrations of radionuclides, the well water may contain levels that exceed the EPA’s standards.

Well water should be tested every three years for radionuclides. Kits for testing well water are available online, in hardware stores, and from many state governments.

This picture shows how a private well at a home pumps water from the groundwater aquifer into a pressure tank, which provides the water to a household or building.

There are different kinds of tests for different radionuclides in well water. Ask your local drinking water office or your local radiation control program for the tests that are most useful to your area. You can find contact information for your state’s radiation control program on the Conference of Radiation Control Program Directors (CRCPD) website.

If you discover that you need a treatment system, radionuclides can be removed from water by installing a treatment system at the tap. These filtration systems are called Point of Use (POU) systems. Several types of POU systems are available. Two types that the EPA has found to work well are ion exchange and reverse osmosis. Often, they collect too much radiation to be disposed of with ordinary trash. The company that installs the POU system or state radiation and solid waste offices will be able to help well owners with proper disposal guidelines.

What You Can Do

  • Treat your drinking well water if necessary. If your well water needs to be treated, there are several organizations that can help you pick the best treatment:
    • Water Quality Association
    • The National Groundwater Association
    • Wellowners.org

Where to Learn More

The U.S. Environmental Protection Agency (EPA)

The EPA is the United States’ regulatory agency for clean water. While the Agency does not regulate private wells, it maintains many resources that are available to better understand how different drinking water programs work.

Private Drinking Water Wells
This webpage provides information about private drinking water well issues like water safety, health risks, and where can you go for additional information.

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

Basic Information about Radionuclides in Drinking Water 
This webpage shows basic information about radionuclides in drinking water, including possible health risks of radionuclides and other contaminants.

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

Radon
This webpage provides links to resources, information, and the EPA guidance on radon in homes and businesses.

Radionuclide Basics: Radon
This webpage provides information about radon in the environment.

The U.S. Department of Health and Human Services (HHS), the Centers for Disease Control and Prevention (CDC)

Because of its role as a public health agency, the CDC maintains resources related to radon in drinking water on their website.

Radon and Drinking Water from Private Wells 
This webpage provides health-related information about radon and drinking water.

The U.S. Department of the Interior (DOI), the U.S. Geological Survey (USGS), National Water-Quality Assessment (NAWQA) Program

In 1991, Congress established the NAWQA to address where, when, why, and how the Nation's water quality has changed, or is likely to change in the future, in response to human activities and natural factors. This includes studies on natural radionuclides in groundwater.

Quality of Water from Domestic Wells in the United States 
This webpage provides information about the NAWQA program's water quality assessments.

Radium Frequently Asked Questions 
This webpage shares answers to frequently asked questions about radium in well water and discusses health effects, drinking water limits, testing for and how to remove radionuclides from well water.

The States

Each state has different policies on well water quality. Some states do not regulate private wells. Check with your local or state office of environmental protection to learn more.

Facts: Private Well Testing (PDF)(14 pp, 896.73 K, About PDF)
New Jersey Department of Health and Senior Services
This document offers information on contaminated private well water in the state of New Jersey and lists how to reduce contaminants if they are discovered.

Radium in Drinking Water
Illinois Department of Public Health
This webpage provides an overview of radium and drinking water concerns regarding radium.

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Last updated on August 9, 2021
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