What levels of radon are dangerous?
The Safe Drinking Water Act Amendment of 1996 requires that the EPA (Environmental Protection Agency) set safe drinking water standards to protect public health. For each chemical, two standards are set, the Maximum Contaminant Level Goal (MCLG) and the Maximum Contaminant Level (MCL). The MCLG is the ideal level below which there is no known health risk. The MCL is set as close as feasible to the MCLG, taking into account the use of technology and the costs associated with treatment. These standards only apply to community water supplies, not private water systems. As far as radon is concerned, there are no federal regulations for radon in air or water, yet. Since radon is a known carcinogen, the MCLG is expected to be zero. The EPA recommends that radon in the air not exceed 4 pCi/L (picocuries per liter). A 1995 Wisconsin DNR publication stated that the radon in water MCL is 20,000 pCi/L, but recommended taking treatment actions at levels of 5,000 pCi/L.1 However, the EPA withdrew i
