Radioactive materials, also called radionuclides, are both naturally occurring and human-made. Radionuclides from naturally occurring sources can get into groundwater and surface waters in Minnesota. When radionuclides break down (decay), they create radiation. Radionuclides are a natural part of our environment, and small amounts of radiation are common in the air, water, and soil around us. Coming in contact with too much radiation can cause health problems.

This information is also available as a PDF document: Radionuclides (Radium) in Drinking Water (PDF)

Different doses of radiation cause different health effects. Drinking water that has radionuclides in it puts you in contact with very low doses of radiation every day. You have a higher risk of getting cancer if you drink water with radionuclides in it every day for many years.

Additional information about radium exposure and health effects can be found at Radium in Drinking Water: Frequently Asked Questions About Health (PDF).

The U.S. Environmental Protection Agency’s (EPA) Radionuclides Rule has four federal standards for radionuclides in drinking water. Safe drinking water should have:

15 picocuries of alpha particles per liter of water (pCi/L) or less
5 pCi/L of combined radium 226/228 or less
20 pCi/L of uranium or less
4 millirem of beta/photon emitters per year (mrem/yr) or less

If you have a private well

The factors that contribute to the presence of radionuclides in Minnesota's well water are not well understood at this point. If you are concerned about radionuclides in your private well, you can pay to have it tested through an accredited laboratory. Contact a Minnesota Department of Health (MDH) accredited laboratory to get a sample container and instructions on how to submit a sample. You can also contact your county to see if they have any programs to make testing your water easier.

You can use the standards in the Radionuclides Rule for your private well. Home water treatment systems, like ion exchange water softeners and reverse osmosis systems, can reduce the levels of some radionuclides in your water. You can learn more about treatment systems at Home Water Treatment. Contact MDH (651-201-4700 or health.drinkingwater@state.mn.us) with questions.

If you are on a public water system

Community public water systems (systems serving where you live) test for radionuclides and ensure levels meet EPA standards. You can find the levels of radionuclides your community water system detected by reading their Water Quality Report (also known as a Consumer Confidence Report [CCR]). You can call your community water system to get a paper copy of your CCR, or you may be able to find it online at Find Your Local CCR.

Natural and human-made radiation surround you every day. About half of the radiation you come in contact with each year is from natural sources, like the sun, soil, and rock. The other half comes from human-made sources, like medical tests (x-rays) and treatments and building and road construction materials. Each source of radiation gives you a different dose of radiation. For example, a radiation medical treatment has an extremely high dose of radiation compared to the very low dose of radiation you get from drinking water with radionuclides. Your lifestyle can also affect how much radiation you come in contact with. Flying in airplanes, living at high altitude, living near a coal mine, and some jobs (like underground mining) put you in contact with higher doses of radiation.

Testing your home for radon (a radionuclide in gas form) and taking steps to reduce the radon level can be one of the most important things you can do to reduce your contact with natural radiation.

Learn more about radiation Doses in Our Daily Lives.

Radionuclides, such as radium, polonium, radon, and uranium, occur naturally in Minnesota and can be found in small amounts in Minnesota's groundwater. In general, surface water does not contain radionuclides at levels of concern.

In 2014, nine (1.2 percent) of Minnesota's municipal water systems (systems that serve homes in towns and cities) had levels of radium in treated water over the EPA standard. MDH studies found that the highest levels of radionuclides in source water occur in the Mount Simon-Hinckley and Jordan Aquifers in southeastern Minnesota. Treatment is required in communities with source water radionuclides levels greater than 5 pCi/L.

Very few of Minnesota's private wells have been tested for radionuclides.

Learn more about radionuclides in Minnesota's Water:

MDH regulates public water systems by:

Approving public water systems’ treatment plans
Enforcing the Safe Drinking Water Act
Testing public water supplies

MDH Environmental Monitoring Program makes sure radiation levels are safe around nuclear generating power plants in Minnesota through sampling water, milk, and air.

MDH conducted a study on the Distribution of Radium in Minnesota Drinking Water Aquifers. Currently, MDH is working on a Radionuclide Assessment Project to learn more about where polonium-210 (a radionuclide) occurs in Minnesota groundwater.

MDH also helps families stay safe from Radon in Minnesota Homes. MDH also provides information on:

Drinking Water Standards for Contaminants: Microbiological, Radiological, and Inorganic Contaminants

The EPA has many resources about radiation:

RadTown USA helps you learn about radiation in your town
Radiation: Facts, Risks and Realities
RadNet monitors the nation’s air, precipitation, and drinking water radiation.
Proposed Radon in Drinking Water Regulation
The U.S. Food and Drug Administration keeps record of Products that Emit Radiation.