Home › Radon in well water
Radon in Well Water: Testing, Risk and Treatment
Some links on this page are affiliate links. If you buy through them we may earn a commission at no extra cost to you. How we make money.
How radon gets into water
Vermont's Department of Health says radon comes from the decay of uranium found naturally in the Earth's crust. It can get into drinking water if a well is drilled into or near rock formations that contain uranium. EPA says a radon-in-water problem is more likely when the source is ground water, and is usually not a problem when the source is surface water.
Radon in water adds to the radon in your indoor air. Vermont says showers, laundry and running the dishwasher can release radon into the air.
Step 1: test the air
EPA says the soil is the main source of indoor radon, so start with an air test. See our test kit guide and the result checker.
Step 2: test the water if you have a private well
- Use a certified lab. Vermont says you cannot see, smell or taste radon, and testing is the only way to know. Water test kits are different from air test kits.
- Radon in well water can vary during the year, so Vermont says it can help to test more than once at different times of the year.
- Vermont's own advisory level for radon in water is 4,000 pCi/L. Below that, it says you do not need to treat your water and should test again in five years. That is Vermont's rule. Other states may differ, so ask your state radon program.
- On a public water supply that uses ground water, EPA says to contact your water supplier. Some public systems treat their water to reduce radon.
- EPA's Safe Drinking Water Hotline is (800) 426-4791.
Step 3: treatment options
| Option | How it works | Cautions (EPA, Vermont) |
|---|---|---|
| Aeration (point of entry) | Mixes the water with air in a tank and vents the air and radon outdoors, using a fan. | EPA says GAC usually costs less than aeration devices. |
| Granular activated carbon filter (point of entry) | A charcoal filter removes the radon from the water. | Filters can collect radioactivity and may need special disposal (EPA). Vermont discourages GAC for radon and says to use a filter with NSF/ANSI Standard 53 certification if you choose one. |
| Point-of-use filter (at one tap) | Treats a small portion of the water, such as drinking water. | Does not reduce the risk from breathing radon released by all the water used in the home (EPA). |
Retest the water after any treatment system is installed to make sure levels are below the health advisory level (Vermont). Contact a certified water treatment specialist.
We did not find a sourced installed price for radon-in-water treatment from a government or extension page, so we do not quote one.
Other well water problems
For testing schedules, filtration and common problems like sulfur smell, iron and hard water, see our sister site Well Water Plan.
Start with the air test
Testing is the only way to know your radon level. A mail-in kit is a low-cost way to start, and our guide shows how to place it so the result is reliable.
How to use a radon test kitBrowse radon test kitsCommon questions
Should I test my well water for radon?
EPA says to test the air in your home first. If you have tested for radon in air, found elevated levels and your water comes from a private well, have your water tested. EPA notes that devices and procedures for testing water are different from those for air.
Is radon in water as dangerous as radon in air?
EPA says radon entering through the soil is usually a much larger risk than radon entering through water. Most of the risk from radon in water comes from radon released into the air when water is used for showering and other household purposes. Vermont's health department adds that drinking radon in water also poses a risk of stomach cancer over a lifetime, but says the major danger is breathing the radon released into the air.
How do I remove radon from well water?
EPA says point-of-entry treatment can effectively remove radon from water before it enters the home. It usually uses granular activated carbon (GAC) filters or aeration devices. Point-of-use devices treat only a small part of your water and do not reduce the risk from breathing radon released by all water used in the home.
Why do some health departments discourage carbon filters?
EPA says GAC filters usually cost less than aeration devices, but filters can collect radioactivity and may require a special method of disposal. Vermont's health department discourages GAC systems for radon because the radon collected on the filter could create a radiation hazard.
Related guides
- Radon test kits
- How radon mitigation systems work
- What radon is and the health risk
- Find a certified contractor
Free printable: Radon Test Day Checklist
EPA's testing steps in one page, plus what your result means. Download the one-page PDF now, or get it by email along with a short series of five helpful emails.