Radon in private well water

How it gets into the house

Radon can come in through well water as well as from the ground. When water runs from taps, showers, dishwashers and washing machines, some of the radon in it escapes into the air. The state health department says homes on a private well should test the well water for radon too.

Massachusetts' guideline

There's no federal limit for radon in private well water. MassDEP's Office of Research and Standards set a guideline of 10,000 pCi/L for radon in drinking water.

Treatment

MassDEP's guidance names two approaches: aeration, which strips radon from the water and vents it outside, and granular activated carbon (GAC) filters. It advises using carbon filters only where radon in the water is below 10,000 pCi/L, because the carbon can become too radioactive to dispose of cheaply.

Where to start

Test the air first; it's the simpler test. If the air is high and you're on a well, test the water too, so the fix addresses the right source.

Next: how to test the air · mitigation