COULD THERE BE RADON IN MY WATER?
Yes, radon can dissolve in the groundwater and be released into the air of the home when it is used for showers, laundry, and other purposes. Most dissolved radon is quickly released when water meets the air.
The concern with radon in water is not widespread and is primarily associated with homes whose water comes directly from groundwater wells.
Municipal water supplies, aerated during purification, pose little or no health concern from radon.
The major concern is not with drinking the water, but rather the additional amount of radon added to the breathing space in a home, school, or workplace. Normal radon-in-air tests will measure this contribution, if the house is occupied and water used routinely during testing. It takes a lot of radon in the water to have a measurable effect on the indoor radon level of a home. As a rule of thumb, it takes 10,000 pCi/L in the water to add one pCi/L to the air.
EPA recommends testing the air first, before becoming concerned about radon in the water. If radon in the air is below the recommended action level, then radon in the water is not a cause for concern. A radon-testing professional should be able to provide additional guidance if needed.
MORE INFORMATION ABOUT RADON IN WATER
Radon in the ground can dissolve into water that finds its way to a well. When well water that contains radon is brought directly into a building, the dissolved gas is released indoors as the water leaves the faucet, showerhead, or other outlet.
The amount of radon brought into the building will depend upon the amount of water used and the amount of radon in the water. Given typical water usage rates and radon concentrations found in wells, this entry mechanism only accounts for about 1-2% of the radon that enters homes in the U.S.
Most indoor radon comes from the soil. Thus, most remediation efforts concentrate on reducing the entry of radon from soil rather than water.
As a rule of thumb, it takes 10,000 pCi/L of radon in the water, to add 1pCi/L of radon to the air in the home, after the radon dilutes and dissipates within the large volume of air indoors. This is above and beyond the amount of radon that comes from the soil.
The US EPA has recommended maximum contaminant levels (MCL) ranging from a low of 300 pCi/L to as high as 4,000 pCi/L of water in community water supplies. The regulation, as proposed, would not impact private wells, and no firm implementation date has been set.
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