Radon in Well Water
Radon dissolved in well water can be released into indoor air. Learn how waterborne radon is tested, and which treatment options reduce it.
If your home uses a private well, radon can be dissolved in the water — and released into the air whenever water is agitated, especially in showers, washing machines and dishwashers. For homes on municipal surface water, this route is generally not a concern because treatment aerates the water first.
How waterborne radon reaches you
- Inhalation is the main pathway: radon escapes from water into indoor air as you shower or run appliances.
- Ingestion is a smaller pathway, but the EPA notes that some risk comes from swallowing water with dissolved radon.
The EPA’s rule of thumb: the larger your airborne radon problem, the more important it is to test the water.
Testing
Water testing is separate from air testing and uses its own sample kit, usually analysed by a laboratory. If you have a private well, test the water as well as the air — especially if an air test is elevated or if you are thinking about mitigation.
Treatment options
| Method | Notes |
|---|---|
| Aeration | Removes radon by bubbling air through water and venting it; typically the most effective, needs more maintenance |
| Granular activated carbon | Adsorbs radon onto carbon; simpler, but the filter becomes radioactive waste and must be handled correctly |
The right choice depends on your water use, radon concentration and the system’s maintenance requirements — a water-treatment professional or your state radon programme can advise.
Water treatment and air mitigation are separate jobs. If your indoor air level is high, fix that first: it usually accounts for most of your exposure. See how to reduce radon.
Frequently asked questions
Is radon in water a problem for city water?
Does a water softener remove radon?
Will an air test show radon coming from water?
Sources
- Radon in Drinking Water — U.S. EPA
- A Citizen's Guide to Radon — U.S. EPA