Radon and Drinking Water from Private Wells

What is radon?

Radon is a colorless, tasteless, odorless, radioactive gas. It occurs naturally and is produced by the breakdown of uranium in soil, rock, and water. It can also dissolve into our water supply.

For more information about radon illness and treatment, please visit CDC’s radon page.

Where and how does radon get into drinking water?

While most radon-related deaths are due to radon gas accumulated in houses from seepage through cracks in the foundation, 30 to 1,800 deaths per year in the United States are attributed to radon from household water. High levels of dissolved radon are found in the groundwater in some areas flowing through granite or granitic sand and gravel formations. If you live in an area with high radon in groundwater it can get into your private well. Showering, washing dishes, and laundering can disturb the water and release radon gas into the air you breathe.

Radon can build up in water from underground sources (groundwater). Radon is not a concern in water from lakes, rivers, and reservoirs (called surface water). Groundwater is the source used in private wells and in some public water supplies. If you have questions or concerns about radon in groundwater, contact EPA using this formexternal icon.

How can I find out whether there is radon in my drinking water?

If you suspect a problem and your drinking water comes from a private well, you may contact your state certification officerexternal icon for a list of laboratories in your area that will perform tests on drinking water for a fee.

How do I remove radon from my drinking water?

Radon can be removed from water by one of two methods:

  • Aeration treatment – spraying water or mixing it with air and then venting the air from the water before use, or
  • GAC treatment – filtering water through granular activated carbon. Radon attaches to the carbon and leaves the water free of radon. Disposing of the carbon may require special handling if it is used at a high radon level or if it has been used for a long time.

In either treatment, it is important to treat the water where it enters your home (point-of-entry device) so that all the water will be treated. Point-of-use devices such as those installed on a tap or under the sink will only treat a small portion of your water and are not effective in reducing radon in your water. It is important to maintain home water treatment units properly. Failure to do so can lead to other water contamination problems. Some homeowners use a service contract from the installer to provide carbon replacement and general system maintenance. Remember to have your well water tested regularly, at least once a year, after installing a treatment system to make sure the problem is controlled.