WHAT IS A SAFE LEVEL OF WATER RADON?
The EPA answers the question “What is a safe level of water radon in the following way:
The “EPA believes that any radon exposure carries some risk – no level of radon is safe.” -Citizens Guide.
WHAT DO I USE FOR A LIMIT NOW?
The State of Maine has set an maximum exposure guideline (MEG) for water. The current State of Maine MEG for water is 4,000 pCi/L.
WHAT IS THE EPA DOING ABOUT SETTING AN MCL FOR WATER RADON?
In 1996 Congress amended the Safe Drinking Water Act (SDWA) to commission the National Academy of Sciences (NAS) to conduct a risk assessment study of radon in water. This report, published in 1998, agreed with previous risk assessments performed by the EPA. The study supported the EPA’s assumption that for every 10,000 pCi/L of radon in water an increase in the indoor air radon as a result of using this water will be 1 pCi/L and the assumption that outdoor radon level averages .4 pCi/L. This report recommended an alternative MCL of 4,000 pCi/l for public drinking water supplies. In 1999 the EPA proposed an MCL of 300 pCi/l and an alternative MCL (AMCL) of 4,000 pCi/L. At present, these are still in the proposal stage.
For more information see the following:
Consumer’s Guide to Radon Reduction , Radon Gas Mitigation , Radon Gas Mitigation Basics , Removal of Radon from Water , Radon and Real Estate Transaction in Maine , Radon in Your Water – from the Experts in Radon Mitigation , What is a Safe Level of Water Radon? , Radon Mitigation Using Air to Air Heat Exchangers