Overview page
Radon in water
How radon gets into water, who it affects most, how a water test differs from an air test, and how elevated water radon is treated.
Open the pageResourcesGuides by topic
Radon in household water
Radon in well and household water: when it matters, how a water test works, and treatment.
Water
What this topic covers
These pages cover radon in household water: private wells, how a water test differs from an air test, and how water treatment works.
“Sometimes radon enters the home through well water.”
EPA “Most of your risk from radon in water comes from radon released into the air when water is used for showering and other household purposes.”
EPA
Guides
Pages in Water
4 to read, the one to start with first.
- Overview page
Well water and radon
Why private wells are the main concern for waterborne radon, and what public water treatment changes about that risk.
- Overview page
Water testing for radon
How a water-specific radon test works, why it is different from an air test, and where to send a sample.
- Overview page
Water treatment for radon
How aeration and granular activated carbon systems reduce radon in water, and how they differ from soil-gas mitigation.
Short answers
Questions in Water
Each with its short answer.
Does radon come from well water?
It can: groundwater from wells normally carries more radon than surface water, and some of that radon escapes into the indoor air when the water is used for showers and other household purposes.
Read the full answerHow do you test for radon in well water?
Test the air first, then, if you have a private well, have the water tested: a sample is collected and sent to a lab that measures its radon, using different devices and procedures from an air test.
Read the full answerHow do you get radon out of water?
Radon is removed from water with point-of-entry treatment, which treats all the water before it reaches the taps, usually by aeration, which typically removes 95 to 99 percent, or a granular activated carbon filter, which typically removes 85 to 95 percent.
Read the full answer