815F06004
Announcement of Final Rule: Revisions to the Unregulated Contaminant
Monitoring Regulation (UCMR) for Public Water Systems
Summary: This action finalizes the design for the second Unregulated Contaminant Monitoring
Regulation (UCMR) cycle (i.e., UCMR 2). Monitoring for 25 unregulated contaminants will occur
during 2008-2010 using five associated analytical methods. The UCMR program was developed in
coordination with the Contaminant Candidate List (CCL). The CCL is a list of contaminants that are not
regulated by national primary drinking water regulations, are known or anticipated to occur at public
water systems, and may warrant regulation under the Safe Drinking Water Act. The data collected
through the UCMR program is being stored in the National Contaminant Occurrence Database (NCOD)
to support analysis and review of contaminant occurrence, to guide the CCL selection process, and to
support the Administrator's determination of whether to regulate a contaminant in the interest of
protecting public health.
Background: The Safe Drinking Water Act (SDWA), as amended in 1996, requires EPA to establish
criteria for a program to monitor unregulated contaminants and to identify no more than 30
contaminants to be monitored every five years. EPA identified and published unregulated contaminants
for the first UCMR cycle (i.e., UCMR 1), and a revised approach for monitoring, in the Federal Register
dated September 17, 1999. EPA subsequently published the proposal for the UCMR 2 rule in the
Federal Register on August 22, 2005.
About this Regulation: EPA is requiring the monitoring of 25 chemicals using five different analytical
methods (see Exhibit 1). EPA is requiring all public water systems (PWSs) serving more than 10,000
people, and a representative sample of 800 PWSs serving 10,000 or fewer people, to conduct
Assessment Monitoring for 10 chemicals (List 1) during a 12-month period between January 2008—
December 2010. EPA will also require all 407 PWSs serving more than 100,000 people and 800 PWSs
serving 100,000 or fewer people to conduct a Screening Survey for 15 chemicals (List 2) during a 12-
month period, also between January 2008 - December 2010. In addition, EPA has made a minor
technical correction related to historical cross-referencing found in section §141.24 that is no longer
applicable.
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Exhibit 1: Contaminant List and Sampling Design
List 1, Assessment Monitoring
1 ,3-dinitrobenzene
2,2l,4,4'-tetrabromodiphenyl ether (BDE-47)
2,2',4,4',5-pentabromodiphenyl ether (BDE-99)
2,2')4,4',5,51-hexabromobiphenyl(245-HBB)
2,2',4,4',5)51-hexabromodiphenyl ether (BDE-153)
2,4,6-trinitrotoluene (TNT)
Dimethoate
Hexahydro-l,3,5-trinitro-l,3,5-triazine(RDX)
Terbufos sulfone
2,2',4,4',6-pentabromodiphenyl ether (BDE-100)
List 2, Screening Survey
Acetochlor
Acetochlor ESA
Acetochlor OA
Alachlor
Alachlor ESA
Alachlor OA
Metolachlor
Metolachlor ESA
Metolachlor OA
N-nitroso-diethylamine (NDEA)
N-nitroso-dimethylamine (NDMA)
N-nitroso-di-n-butylamine (NDBA)
N-nitroso-di-n-propylamine (NDPA)
N-nitroso-methylethylamine (NMEA)
N-nitroso-pyrrolidine (NPYR)
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How did EPA select these contaminants? EPA reviewed contaminants that had been targeted through
existing prioritization processes, including contaminants considered for the previous UCMR for which
analytical methods were not yet available and Contaminant Candidate List (CCL) priority contaminants.
We identified additional contaminants of concern based on current research on occurrence and health
effects risk factors. We eliminated any pesticides that were not registered for use in the United States,
contaminants that did not have an analytical reference standard, and any contaminants whose analytical
methods were not ready for use. We further prioritized the remaining contaminants based on more
extensive health effects evaluations by the Office of Water's Office of Science and Technology. These
procedures for evaluating health effects scores were developed to support the ranking of contaminants
for future CCLs.
What are the major differences between UCMR 1 and 2? This final rule builds on the established
structure of UCMR 1, and makes some changes to improve the rule design. The primary changes to
UCMR 1 include: (1) redesign of the Screening Survey to add more PWSs to provide a more nationally
representative sample of water systems; (2) updates to the lists of contaminants to be monitored and the
analytical methods approved to conduct that monitoring; (3) revisions to the "data elements" required to
be reported; (4) extending the monitoring period for List 2, Screening Survey contaminants to the same
three years of List 1, Assessment Monitoring; (5) establishing month and year schedules for large PWSs;
and (6) making some revisions to the implementation of the monitoring program to reflect "lessons
learned" during UCMR 1. hi addition, a new systematic procedure for the determination of a minimum
reporting level (MRL) is also being used to support UCMR 2.
What are the environmental and public health benefits? This final rule will benefit the environment
and public health by providing EPA and other interested parties with scientifically valid data on the
occurrence of these contaminants in drinking water, permitting assessment of the population potentially
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being exposed and the levels of that exposure. This information is the primary source of occurrence and
exposure data for the Agency to determine whether to regulate these contaminants.
What is the EPA Laboratory Approval Program for UCMR 2? Laboratories interested in analyzing
samples for (PWSs) that are subject to the UCMR 2 monitoring requirements need to register for the
EPA Laboratory Approval Program. Laboratories will then need to complete and submit method-
specific application packages. Upon review, qualified labs will then be eligible to participate in a
Proficiency Testing (PT) program. Laboratories that successfully complete the PT Program will be
granted method-specific approval to analyze samples once the final UCMR 2 is promulgated.
Laboratories interested in registering for the Laboratory Approval Program should send their request to:
UCMR 2 Laboratory Approval Coordinator
USEPA, Technical Support Center
26 West Martin Luther King Drive (MS 140)
Cincinnati, OH 45268.
What is the cost of the regulation? Over the five-year cycle (2007-2011), respondents to UCMR 2
will include 1,280 small PWSs (i.e., about 2 percent of the approximately 63,000 small systems serving
10,000 or fewer people), the 3,226 large PWSs serving 10,001 to 100,000 people, 407 large PWSs
serving more than 100,000 people, and the 56 states and primacy agencies (referred to collectively as
"states" for simplicity in this document), for a total of 4,969 respondents. EPA estimates that the total
national cost for the five-year, UCMR 2 monitoring program is approximately $44.34 million (as shown
in Exhibit 2, below). As noted below, the total cost to EPA is $12.85 million, of which $9.02 million
represents small system monitoring and reporting costs paid by EPA using a national set-aside from the
Drinking Water State Revolving Fund. EPA estimates that costs will be incurred as follows.
Exhibit 2: Total Estimated Costs of UCMR 2 for 2007-2011 (in millions)
USEPA
56 States and Territories
1,280 small systems serving < 10,000 people
3,226 large systems serving 10,001 to 100,000 people
407 large systems serving >1 00,000 people
National Total over 2007-201 1
$12.85
$2.45
$0.30
$19.20
$9.54
$4434
How to can I get additional information? For general information on UCMR 2, please visit the EPA
Safewater Web site at: http://www.epa.gov/safewater/ucmr/index .html or contact the Safe Drinking
Water Hotline at 1 -800-426-4791. The Safe Drinking Water Hotline is open Monday through Friday,
excluding legal holidays, from 9:00 a.m. to 5:00 p.m., Eastern time. For a copy of this fact sheet, the
Federal Register notice, and/or any of the supporting documents for the UCMR 2 regulation, please
contact EPA's Water Resource Center at 1-800-832-7828 and reference the publication number at the
bottom of this page.
Office of Water (MS 140)
December 2006
EPA815-F-06-004
www.epa.gov/safewater
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