Radon in well water

Soil is the most common source of radon in your home, but well water that contains radon can raise the level of radon in your home's air too.^[1]

How radon gets into water

Radon comes from the decay of uranium, which is found naturally in the Earth's crust. It can get into your drinking water if your well is drilled into or near rock formations that contain uranium.^[1] Showers, laundry and running the dishwasher can release radon from the water into the air.^[1]

Testing your water

You can't see, smell or taste radon; testing is the only way to know if it's in your water.^[1]

• Order a radon in water test kit for $25 from the Health Department Laboratory.^[1][2] You can also call the Lab at 802-338-4724.^[3]
• Or use another certified drinking water lab.^[1][4]
• The Lab is running a study on radon in water that provides free test kits for wells and springs. A limited number of tests are available.^[1][5]

Radon in well water can vary through the year, so testing more than once at different times of year can help.^[1]

Test your air too. The Health Department says you need your radon in air result to fully understand your risk, and if you haven't tested your air, to do that before deciding how to reduce radon.^[1] If your air result is 4.0 pCi/L or higher and you're on a well, it recommends testing your water.^[6]

What your water result means

The Health Department's advisory level for radon in water is 4,000 pCi/L.^[1]

• Below 4,000 pCi/L: you don't need to treat your water. Test again in five years.^[1]
• At or above 4,000 pCi/L: take action to reduce radon levels in your home. The radon contribution calculator can estimate how much of your indoor air radon comes from your water versus your foundation, which helps you pick the right fix.^[1][7]

Treatment options

• Aeration: uses a fan to mix water with air in a tank, then vents the radon outdoors. Estimated at around $7,000 installed.^[1][6]
• Granular activated carbon (GAC): a charcoal filter. The Health Department discourages GAC for radon because radon collected on the filter could create a radiation hazard. If used, it says to choose a system with NSF/ANSI Standard 53 certification. Estimated at around $2,000.^[1][6]

Retest your water after any treatment system is installed.^[1] To find a certified water treatment specialist, the Health Department points to the Water Quality Association directory.^[1][8] Funding may be available to help pay for water treatment or repairs.^[1][9]