Frequent Questions

What are the federally-enforced standards for Radon in Drinking Water?

Radon does not currently have any enforceable standards under the Safe Drinking Water Act. EPA has proposed to regulate radon in drinking water from community water suppliers. Community water systems are defined as water systems that serve 25 or more year-round residents. The proposed requirements would guide community water suppliers into ensuring that they provide water with radon levels no higher than 4,000 pCi/L, which contributes about 0.4 pCi/L of radon to the air in your home.  This requirement assumes that the State is also taking action to reduce radon levels in indoor air by developing EPA-approved, enhanced State radon in indoor air programs (called Multimedia Mitigation Programs).  This is because most of the radon you breathe comes from soil under the house.  This option gives States the flexibility to focus on the greatest problems, by encouraging the public to fix radon in indoor air problems and build homes that keep radon from entering. For states that do not choose to develop enhanced indoor air programs, community water systems in that State will be required to reduce radon levels in drinking water to 300 pCi/L.  This amount of radon in water contributes about 0.03 pCi/L of radon to the air in your home.  Even if a State does not develop an enhanced indoor air program, water systems may choose to develop their own local indoor radon program and meet a radon standard for drinking water of 4,000 pCi/L.

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