The 1996 Safe Drinking Water Act Amendments required EPA to establish several new, health-based drinking water regulations. The first of these set requirements for microbial and disinfection byproducts.  The multimedia proposal for radon will be the second of these health-based drinking water regulations.

Radon in the indoor air of homes is the primary public health risk from radon, contributing to about 20,000 lung cancer deaths each year in the United States, according to a landmark report this year by the National Academy of Sciences (NAS) on radon in indoor air. Radon is the second leading cause of lung cancer in the United States. Based on a second NAS report on radon in drinking water, EPA estimates that radon in drinking water causes about 168 cancer deaths per year, 89 percent from lung cancer caused by breathing radon released from water, and 11 percent from stomach cancer caused by drinking radon-containing water.

Proposed Regulations

EPA is proposing new regulations to reduce the public health risks from radon.  The proposed standards would apply only to community water systems that regularly serve 25 or more people and that use ground water or mixed ground and surface water (e.g., systems serving homes, apartments, and trailer parks).  They would not apply to systems that rely on surface water where radon levels in the water are very low. They also would not apply to private wells, because EPA does not regulate them.

The proposal will provide states flexibility in how to limit exposure to radon by allowing them to focus their efforts on the greatest radon risks -- those in indoor air -- while also reducing the risks from radon in drinking water.

The unique multimedia framework for this proposed regulation is outlined in the Safe Drinking Water Act, as amended in 1996.

First Option:
States can choose to develop enhanced state programs to address the health risks from radon in indoor air -- known as Multimedia Mitigation (MMM) programs -- while individual water systems reduce radon levels in drinking water to 4,000 pCi/L (picoCuries per liter, a standard unit of radiation). EPA is encouraging States to adopt this option because it is the most cost-effective way to achieve the greatest radon risk reduction.

Second Option:
If a state chooses not to develop an MMM program, individual water systems in that state would be required to either reduce radon in their system's drinking water to 300 pCi/L or develop individual local MMM programs and reduce levels in drinking water to 4000 pCi/L. Water systems already at or below the 300 pCi/L standard will not be required to treat their water for radon.

The proposed regulation identifies four criteria that MMM program plans would be required to meet to be approved by EPA:

• Public involvement in the development of the MMM plan;
• Quantitative goals for reducing radon in existing and new homes;
• Strategies for achieving these quantitative goals; and
• A plan for tracking and reporting results.

EPA sought extensive input from the states, water systems, environmental groups, and the general public in a series of public meetings over the past two years to design the proposed approach.

EPA is soliciting formal comment by publishing the proposed regulation in the Federal Register for a 60 day review and comment period. Comments must be received 60 days after publication of the notice. For specific instructions, see the Federal Register notice's section. A copy of the Federal Register notice of the proposed regulation can be obtained by contacting the Safe Drinking Water Hotline at (800) 426-4791. It is also posted on EPA's Drinking Water website.

For More Information

For general information on radon in drinking water, visit EPA's Radon in Drinking Water website or contact the Safe Drinking Water Hotline, at 800.426.4791. The Safe Drinking Water Hotline is open Monday through Friday, excluding Federal holidays, from 9:00 a.m. to 5:30 p.m. Eastern Time. For more information on radon in indoor air, contact the National Safety Council's Environmental Health Center hotline at (800) SOS-RADON. Or, visit EPA's radon in indoor air web site at http://www.epa.gov/iaq/radon for more information.