Proposed Radon in Drinking Water Rule
The 1996 Safe Drinking Water Act Amendments required EPA to establish
several new, health-based drinking water regulations, including a multimedia
approach to address the public health risks from radon.
Breathing 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 1999 landmark report this year by
the National Academy of Sciences (NAS) on radon in indoor air (BEIR
VI). 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.
EPA proposed new regulations to reduce the public health risks from radon
on November 2, 1999 in the Federal Register (64 FR 59246).
The proposed standards will 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 will not apply to systems that rely on surface water
where radon levels in the water are very low. They also will 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
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 or lower (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 300 pCi/L standard would 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. To read summaries of these
EPA solicited formal comment by publishing the proposed regulation in the
Federal Register for a review and comment period. The public comment
period was open until February 4, 2000. For further information, see the
Federal Register Notice or contact the Safe Drinking Water Hotline, at
1 (800) 426-4791.
Additional Background Information
EPA published a Health
Risk Reduction and Cost Analysis (HRRCA), signed on February 5, 1999,
in the Federal Register for public comment. The HRRCA provided a neutral
and factual analysis of the costs and benefits, and other impacts of controlling
radon levels in drinking water. EPA received many comments and provided
responses to significant comments in the proposed rule. The HRRCA has been
revised and is now part of the "Regulatory Impact Analysis and Revised
Health Risk Reduction and Cost Analysis" document. This document is available
for review in the OW Docket (hard copy and electronic PDF file).
A report, released September 15, 1998, by the National Academy of Sciences,
"Risk Assessment of Radon in Drinking Water", is the most comprehensive accumulation
of scientific data on the public health risks of radon in drinking water.
The report provided scientific basis for EPA's development of the proposed
drinking water standard for radon.
EPA withdrew the 1991 proposed MCL for radon on August 6, 1997 (Federal
Register: Volume 62, Number 151, page 42221-42222).
For More Information
The Safe Drinking Water Hotline is open Monday through Friday, 10:00 am to 4:00 pm eastern. The Hotline is closed on Federal holidays, except Veteran’s Day. The Hotline is open on Veteran’s Day but closed the day after Thanksgiving.
For more information on radon in indoor
air, contact the National Safe Council's Environmental Health Center's
hotline at (800) SOS-RADON Monday through Friday, from 9:00 a.m. to 5:00
p.m. Eastern Time. Or visit EPA's website on radon
in indoor air for more information.