What is a safe level of water radon?
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 recommends treating the water when the radon concentration in the water is 4,000 pCi/L or greater.
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.







