Proposed Radon in Drinking Water Rule Technical Fact Sheet

United States Office of Water EPA 815-F-99-006
Environmental Protection (4607) October 1999
Agency

vxEPA Proposed Radon in Drinking Water Rule
T -E «C «H «N •! «C 'A -L F 'A • C • T • S • H • E • E -T
The U.S. Environmental Protection Agency (EPA) is proposing new regulations to protect
people from exposure to radon. The proposed regulations will provide States flexibility in how
to limit the public's exposure to radon by focusing their efforts on the greatest public health risks
from radon - those in indoor air - while also reducing the highest risks from radon in drinking
water. The framework for this proposal is set out in the Safe Drinking Water Act as amended in
1996, which provides for a multimedia approach to address the public health risks from radon in
drinking water and radon in indoor air from soil. The Safe Drinking Water Act directs the EPA
to propose and finalize a maximum contaminant level (MCL) for radon in drinking water, but
also to make available an alternative approach: a higher alternative maximum contaminant level
(AMCL) accompanied by a multimedia mitigation (MMM) program to address radon risks in
indoor air. This framework reflects the unique characteristics of radon: in most cases, radon
released to indoor air from soil under homes and buildings is the main source of exposure and
radon released from tap water is a much smaller source of radon in indoor air. It is more cost-
effective to reduce risk from radon exposure from indoor air, than from drinking water. EPA
strongly encourages States to take full advantage of the flexibility and risk reduction
opportunities in the MMM program.

WHAT ARE THE PUBLIC HEALTH CONCERNS?

Radon is a naturally-occurring radioactive gas that emits ionizing radiation. National and
international scientific organizations have concluded that radon causes lung cancer in humans.
Most of the radon in indoor air comes from the breakdown of uranium in soil beneath homes.
Breathing radon from the indoor air in 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 by the National Academy of Sciences (NAS) on radon in indoor air. The
U.S. Surgeon General has warned that radon in indoor air is the second leading cause of lung
cancer. EPA and the U.S. Surgeon General recommend testing all homes and apartments
located below the third floor for radon in indoor air. If you smoke and your home has high
indoor radon levels, your risk of lung cancer is especially high.

Radon from tap water is a smaller source of radon in indoor air. Only about 1-2 percent of
radon in indoor air comes from drinking water. However breathing radon released to air from
household water uses increases the risk of lung cancer over the course of your lifetime.
Ingestion of drinking water containing radon also presents a risk of internal organ cancers,
primarily stomach cancer. This risk is smaller than the risk of developing lung cancer from
radon released to air from tap water. Based on a second 1999 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 in radon released from water, and 11 percent
from stomach cancer caused by drinking radon-containing water.

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  WHO MUST COMPLY WITH THE PROPOSED RULE?
The proposed radon in drinking water rule applies to all community water systems (CWSs) that
use ground water or mixed ground and surface water (e.g., systems serving homes,
apartments, and trailer parks). The proposed rule would not apply to CWSs that use solely
surface water, nor to non-transient non-community public water supplies and transient public
water supplies (e.g., systems serving schools, office buildings, campgrounds, restaurants, and
highway reststops).

  WHAT DOES THE RULE PROPOSE TO REQUIRE?
The rule proposes a maximum contaminant level goal (MCLG), a maximum contaminant level
(MCL), an alternative maximum contaminant level (AMCL), and requirements for multimedia
mitigation (MMM) program plans to address radon in indoor air.  The proposal also includes
monitoring, reporting, public notification and consumer confidence report requirements,
proposed best available technologies and analytical methods.

Maximum Contaminant Level Goal (MCLG), Maximum Contaminant Level (MCL), and
Alternative Maximum Contaminant Level (AMCL)
The proposed MCLG for radon in drinking water is zero. This is a non-enforceable goal.

The proposed regulation provides two options for the maximum level of radon that is allowable
in community water supplies. The proposed MCL is 300 picoCuries per liter (pCi/L) and the
proposed AMCL is 4,000 pCi/L. The drinking water standard that would apply for a system
depends on whether or not the State or CWS develops a MMM program. The regulatory
expectation of CWSs serving 10,000 persons or less is that they meet the 4,000 pCi/L AMCL
and be associated with an  approved MMM program plan - either developed by the State or by
the CWS.

The enforceable MCL or AMCL would apply under the following circumstances:
Small CWSs: Proposed regulatory expectation for systems that serve 10,000 or fewer people
Does State develop MMM
program?
yes
no
Does CWS develop local MMM
program?
not needed
yes**
CWS Complies with:
AMCL: 4000 pCi/L*
AMCL: 4000 pCi/L
  Small systems may elect to comply with the MCL of 300 pCi/L
** Small systems may elect to comply with the MCL of 300 pCi/L, instead of developing a local MMM program.

Large CWSs: Proposed compliance options for systems that serve more than 10,000 people
Does Sfafe develop MMM
program?
yes
no
no
Does CWS develop local MMM
program?
not needed
yes
no
CWS Complies with:
AMCL: 4000 pCi/L*
AMCL: 4000 pCi/L
MCL: 300 pCi/L
 Large systems may elect to comply with the MCL of 300 pCi/L

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Monitoring Requirements
CWSs must monitor for radon in drinking water according to the requirements described in the
table below and report their results to the State. If the State determines that the radon level in a
CWS is below 300 pCi/L, the system only needs to continue meeting monitoring requirements
and is not covered by the requirements regarding MMM programs.
Type
Frequency
Condition
Initial
Four consecutive quarters
of monitoring for one year.
At each entry point to the distribution system which is
representative of each well after treatment and/or storage
Routine
One sample per year
If running average from four consecutive quarterly
samples is less than MCL/AMCL, and at the discretion of
State.
Reduced
One sample every three
years
If average from four consecutive quarterly samples is less
than 1/4 the MCL/AMCL, no samples exceed the
MCL/AMCL, and State determines the system is "reliably
and consistently below MCL/AMCL."
Increased
Four consecutive quarters
of monitoring
If the MCL/AMCL for radon is exceeded in a single
sample, when monitoring annually. Can return to one
sample per year if meet routine monitoring conditions,
listed above.
One sample per year
If the radon level is less than MCL/AMCL but above 1/4
MCL/AMCL in a single sample, when monitoring once
every three years. Can return to one sample per three
years if average from four consecutive annual samples is
less than 1/2 the MCL/AMCL.
Waivers
One sample per 9 years
Based on previous analytical results, geological
characteristics of source water aquifer and if a State
determines that radon levels in drinking water are reliably
and consistently below the MCL/AMCL. All analytical
results must be below 1/2 the MCL/AMCL.
Multimedia Mitigation (MMM) Program Plan Criteria
EPA has identified four criteria that State MMM program plans are required to meet to be
approved by EPA. The MMM program is modeled on the National Indoor Radon Program
implemented by EPA, States, and others to address radon in indoor air. The program has been
successful in achieving indoor radon risk reduction through a variety of program strategies,
which form the basis for EPA's proposed MMM program plan criteria.

The MMM program is intended to provide a more cost-effective alternative to achieve radon risk
reduction, by allowing States (or CWSs) to address radon in indoor air from the soil source,
while reducing the highest levels of radon in drinking water. It is EPA's expectation that most
States will adopt State-wide MMM programs as the more cost-effective approach. Most of the
States currently have indoor radon programs that are addressing radon risk from soil, and can
be used as the foundation for developing MMM programs approved by EPA under the SDWA.
EPA expects that State indoor radon programs will implement MMM programs under
agreements with the State drinking water programs. MMM program plans developed by Indian
tribes will be reviewed by EPA, according to these same criteria. In non-MMM States, CWSs
may develop local MMM program plans meeting these criteria (in a manner appropriate to their

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size and institutional capabilities), to be approved by the State.

Under the proposed requirements, an MMM program plan to address radon in indoor air must
address four criteria:
       1.     Public involvement in development of the MMM program plan.
       2.     Quantitative goals for existing homes fixed and new homes built radon-resistant.
       3.     Strategies for achieving the goals.
       4.     Plan to track and report results.

Best Available Technology (BAT) for Radon in Drinking Water Removal
High-performance aeration is the proposed BAT for all systems. High Performance Aeration is
defined as the group of aeration technologies that are capable of being designed for high radon
removal efficiencies (up to 99.9% Removal), i.e., Packed Tower Aeration, Multi-Stage Bubble
Aeration and other suitable diffused bubble aeration technologies, Shallow Tray and other
suitable Tray Aeration technologies, and any other aeration technologies that are capable of
similar high performance.  In addition to listing BAT, which is based on technology evaluations
for large systems, the SDWA directs EPA to list "Small  Systems Compliance Technologies"
(SSCTs): affordable and technically feasible technologies based upon technology evaluations
for small systems.  EPA is proposing that high performance aeration, granular activated carbon
(GAC), and point-of-entry GAC be listed as SSCTs. Issues relevant to safe operation
procedures and safe and legal disposal of spent GAC material are addressed in the preamble
to the proposed radon rule. They will also be addressed in a guidance manual for small
systems, to be issued in support of the final  rule.

Analytical Methods
EPA proposes Liquid Scintillation Counting (Standard Method 7500-Rn)  and de-emanation
("Lucas Cell") as the approved methods.  The Liquid Scintillation Counting method designated
"D 5072 - 92" by the American Society for Testing and Materials (ASTM) is proposed as an
alternate method.

Community Water System Public Notification and Consumer Confidence Report Requirements
The proposed rule adds violation of the radon rule to the list of violations requiring public notice
under the May 13, 1999, proposed public notification rule.  Public notices must be distributed
within 30 days after the violation of the MCL or AMCL is known (Tier 2 public notice).  For
violations of the MMM program plan, public notices must be distributed within a year of violation
(Tier 3 public notice). In addition, the proposed rule adds special requirements to the consumer
confidence report that are intended to encourage public participation in development of the
MMM  program plan. Specific language is provided.

State Primacy, Record Keeping, and Reporting Requirements
The proposed rule requires States to adopt several regulatory requirements, including public
notification requirements and MCL/AMCL for radon. In  addition, States and eligible Indian
tribes  will be required to adopt several special primacy requirements for  the radon rule if they
adopt the AMCL/MMM option. If the State adopts the MCL, the State would be required to
review and approve CWS MMM program plans.  The proposed rule includes additional
reporting requirements for MMM program plans.  The proposed rule also requires States to
keep specific records in accordance with existing regulations.

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 WHAT ARE THE PROPOSED COMPLIANCE DEADLINES?
EPA proposes to require that CWSs begin their initial monitoring requirements (one year of
quarterly monitoring) for radon by 3 years after publication of the final rule in the Federal
Register.  However, CWSs in States that submit a letter to the Administrator committing to
develop an MMM program plan, in accordance with the statute (due 90 days after publication of
final regulation in Federal Register), are required to begin one year of quarterly monitoring 4.5
years after publication of the final rule. If monitoring data collected after proposal of the rule are
consistent with the requirements specified in the regulation, then the State may allow the
systems to use those data to satisfy the monitoring requirements for the initial compliance
period. Systems opting to conduct early monitoring will not be considered in violation of the
MCL/AMCL until after the end of the initial monitoring period applicable to their State (i.e., 4
years after publication of the final rule; 5.5 years after publication of final  rule if State submits
letter of commitment to MMM). In  a non-MMM State, CWSs would need  to notify the State of
its intention to develop and submit a local MMM program plan to the  State by 4 years after the
final rule  is published and implement a local program by 5.5 years  after the final rule.  EPA
plans to publish the final rule by August, 2000.

Activity
States submit primacy
applications and notify CWSs
of decision on MMM/AMCL
Rule Effective (systems begin
initial monitoring)
States implement MMM
Systems complete initial
monitoring
Systems notify State of intent
to submit local MMM program
plans
Systems submit local MMM
plan to State for approval
Systems implement local
MMM programs
Compliance Deadline*
State submits commitment
letter on MMM to EPA - 90
days after final rule
(State MMM/AMCL)
August, 2002
(include MMM program plan in
primacy application)
February, 2005
February, 2005
February, 2006
Not applicable
Not applicable
Not applicable
State does not submit 90-day
commitment letter on MMM
Program
(system MMM/AMCL, or MCL)
August, 2002
August, 2003
Not applicable
August, 2004
August, 2004
August, 2005
February, 2006
*Proposed compliance date if final rule published August, 2000.

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  WHAT ARE THE COSTS OF THE PROPOSED RULE?
Under this proposal, States, CWSs, and the public will have flexibility in how to limit the public's
exposure to radon.  The AMCL/MMM approach is the more cost-effective way to reduce the
risks from radon exposure.  States will  be able to set goals that focus on the more significant
risk of radon in indoor air, and to reduce the highest risks in drinking water which will protect
public health.  EPA estimates the costs to States and community water systems of the more
cost-effective approach, i.e., reducing radon in indoor air while implementing the 4000 pCi/L
drinking water standard, to be approximately $80 million a year. Treating drinking water from
ground water sources to 300 pCi/L, would cost States and systems about $407.6  million a
year.


  HOW CAN I COMMENT ON THE PROPOSED RULE?
EPA is soliciting public comment on the proposed radon in drinking water rule. EPA must
receive comments, in writing, by 60 days after the publication date of the proposed rule in the
Federal Register.  For specific instructions, see the Federal Register notice's "Addresses"
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 web site at http://www.epa.gov/safewater.


  HOW CAN I GET ADDITIONAL INFORMATION?


For general information on radon in drinking water,  contact the Safe Drinking Water Hotline, at
(800) 426-4791, or visit EPA's web site on radon in drinking water at
http://www.epa.gov/safewater/radon.html. 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's hotline at (800) SOS-RADON. Or visit EPA's web site on radon
in indoor air at http://www.epa.gov/iag/radon/.

For technical inquiries regarding the proposed regulations, contact Sylvia Malm, Office of
Ground Water and Drinking Water, U.S. Environmental Protection Agency (mailcode 4607),
401 M  Street, SW, Washington  DC, 20460. Phone: (202) 260-0417. E-mail:
malm.sylvia(S)epa.gov.  For inquiries regarding the  proposed multimedia mitigation program,
contact Anita Schmidt,  Office of Radiation and Indoor Air, U.S. Environmental Protection
Agency, (mailcode 6609J), 401  M Street, S.W, Washington, DC, 20460.  Phone:  (202) 564-
9452.  E-mail: schmidt.anita(S)epa.gov.

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