For Immediate Release: October 21, 1999

Radon Not Detected In MWRA Water

Responding to customer questions arising from the US Environmental Protection Agency’s recent announcement that it plans to regulate the amount of radon allowed in drinking water, MWRA today announced that testing results for radon performed in November, 1998 at five locations in the MWRA system all came up below detection limits. The level of detection used by MWRA for the testing process is approximately 40 picocuries per liter (pCi/l) (a measure of radioactive decay).

The EPA proposal, expected to be issued as a final regulation next August, calls for states to meet a 4,000 pCi/l of radon drinking water standard as long as states develop an "enhanced state program addressing radon in indoor air" in conjunction with the water program. Without such an aggressive air quality protection program, states or local water authorities would have to limit radon in drinking water to 300 pCi/l. Water systems such as MWRA where radon is already below 300 pCi/l would not have to take additional action.

Radon is a naturally occurring gas that comes from soil. The gas has been linked to thousands of cases of lung cancer. The National Academy of Sciences’ National Research Council reported last month that radon consumed in drinking water poses a relatively small cancer risk compared with radon inhaled from the air. Radon is found almost exclusively in groundwater.

Testing for radon is not mandatory and goes beyond the routine testing currently required by EPA under the Safe Drinking Water Act. MWRA routinely tests for 122 contaminants. These results were recently published in MWRA’s annual Report To Consumers on Your Drinking Water distributed to every household in MWRA’s water service area.

Full radon test results and copies of the Report To Consumers on Your Drinking Water are available by calling the MWRA Waterworks Division at (617) 242-5323 or visit MWRA on the web at


Go to: Front Page