Radon in Private Wells

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Radon can be transported into a home through the plumbing of homes receiving water from a well. The concern with high levels of radon in water is that it can elevate the levels of radon in the home’s air. When testing water for radon, it is important to know that the data result, the number value, is viewed differently.


The NC Radon Program recommends that you first test your air for elevated radon levels. Should your radon test for the air indicated an elevated radon level, testing for radon in your well-water maybe helpful to determine if the home’s plumbing is the pathway in which the radon is entering your home.


The NC Radiation Protection Section advises homeowners with private wells to follow the recommendations set forth by the North Carolina Radon-in-Water Advisory Committee. These recommendations, found on page 5 of the final report, are as follows:


Private wells with radon concentrations at or above 10,000 pCi/L: Treatment of water should be considered in conjunction with a radon in air mitigation system.


Private wells with radon concentrations between 4,000 and 10,000 pCi/L: Treatment of water should be considered optional.


This recommendation is made recognizing that the radon-concentration in water is to help determine whether water is a significant contributor to existing indoor air radon levels. Inhalation of radon in air poses a greater health risk than ingestion of radon through water. The recommendation seeks to address the combined sources of radon from soil gas and radon released from water. The goal is to limit the combined radon exposure in the home to no more than the Environmental Protection Agency (EPA) recommended level of 4 pCi/L. As a general rule, 10,000 pCi/L radon in water will contribute 1 pCi/L radon to the air in the home.


The risk of radon in drinking water has been estimated by the EPA to cause 168 cancer deaths per year in the United States. The majority of these deaths (about 89%) are caused by breathing in radon that has gassed out of the water while washing dishes or showering, which leads to lung cancer. Overall, lung cancer deaths from airborne radon are estimated to be about 20,000 per year in the U.S. For this reason, it is always recommended that homeowners test for airborne radon in their home, as this presents the greater risk.


Testing for radon in air or water is easy and affordable. There are a number of radon test kits available online or in your local home improvement store for $20 or less.



North Carolina Radiation Protection Section

5505 Creedmoor Rd, Suite 100, Raleigh, NC 27612

1645 MSC, Raleigh NC 27699-1645


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