FAQ > Water Quality Issues > How much radon is too much?
The Radon Air limit is 4.0 pCi/L. If your result is near that level it is recommended you retest at least a month later before purchasing treatment. Radon is a gas, and many factors affect the amount of radon in the sample taken, such as: temperature, atmospheric pressure, prior well pumping, and the level of saturated soil above the bedrock. It would be best to get an average of your radon levels over different conditions for a more representative result.
At this time New Hampshire Department of Environmental Services, and the EPA, have not set a standard for Radon levels in the water. Proposed amounts have been: 300 pCi/L, 2,000 pCi/L, and 4,000 pCi/L. Over 95% of NH wells exceed 300 pCi/L. Nearby states have adopted their own limits, which vary greatly: Maine 4,000 pCi/L; Massachusetts 10,000 pCi/L; Vermont 5,000 pCi/L. It is not expected the EPA would use a limit above 4,000 pCi/L.
You can read more in the Fact Sheet Radon in the Air and Water and Radium, Radon, and Uranium
