SEPA
                  United States
                  Environmental Protection
                  Agency
T
his  fact sheet describes the  Unregulated Contaminant Monitoring  Regulation (UCMR).
It provides information for water systems and consumers.
What Is the Unregulated Contaminant Monitoring Regulation?
UCMR is  a tool for the U.S.  Environmental Protection Agency (EPA) to find unregulated
contaminants of concern in the nation's drinking water. The Safe Drinking Water Act gives
EPA the responsibility to protect public health and to set minimum standards for drinking water.
To do this, EPA identifies contaminants that might be harmful to human health. (A contaminant
is any physical, chemical, biological, or radiological substance or matter in water.) EPA then
determines whether to set drinking water standards for individual contaminants  or to require
water  providers to use certain treatment processes  to reduce or eliminate contaminants in the
drinking water.

As a part of this process, EPA works with local water systems to periodically test the water that
is delivered to consumers' homes for contaminants that are not regulated. This helps EPA to
know  whether these contaminants occur often  enough and at high enough levels to warrant
further attention. This testing takes place as part of the Unregulated Contaminant Monitoring
Regulation, or UCMR. EPA is currently implementing the second cycle of UCMR testing (with
monitoring taking place from 2008-2010), called UCMR2.

Which Water Systems Participate in UCMR2?
EPA requires all public water  systems serving more than 10,000 people to participate.  EPA
also requires some smaller systems serving 10,000 people or fewer to participate. EPA selects
smaller systems based on factors such as  the number of people they serve, where they are
located, and whether they use water from a source such as a river or a  well. Together, these
water  systems gather  the  information EPA needs to determine  if and how often these
contaminants occur in drinking water. Almost 5,000 systems are participating in UCMR2.

What Contaminants Are Systems Looking for as Part of  UCMR2?
EPA considered more than 200  contaminants for further testing and selected 25 that it considers
most important. (EPA can select up to 30 contaminants every five years.) The contaminants were
selected for three main reasons:

• EPA believes that they are likely to occur in drinking water.

• They could be harmful.

• There are testing methods to look for them in drinking water.

EPA divided the 25 contaminants into  two lists.  The 10 "List 1"  (Assessment Monitoring)
contaminants are monitored using testing methods that are more widely used. They  include flame
retardants  (materials that stop  fires  from  spreading), contaminants  used  in explosives,  and
contaminants related to insecticides. The  15 "List 2" (Screening  Survey) contaminants are
monitored using testing methods that are relatively new. They include nitrosamines (chemical
compounds that exist in  sources of drinking water or that form when disinfectants are added to
water to kill microbes), herbicides (used to kill unwanted plants), and herbicide degradate (formed
when herbicides change in the natural environment).
Spotlight on
NDMA and Other
Nitrosamines
Nitrosamines are
chemical compounds
that can be present in
water. NDMA is
among the more
studied of the six
nitrosamines being
monitored as a part
ofUCMR2.

EPA is currently
evaluating the health
effects of
nitrosamines.
Nitrosamines can
exist in sources of
drinking water or can
form when
disinfectants are
added to water to kill
microbes. As a part
ofUCMR2,
thousands of water
systems are
collecting information
on how often
nitrosamines occur in
drinking water.

This UCMR2 testing
will give EPA
information on how
often and at what
levels nitrosamines
occur in drinking
water. EPA will use
the UCMR2 results,
along with health
effects and other
information, to
determine whether
nitrosamines warrant
further attention.

-------
  UCMR and the
  Contaminant
  Candidate List
  UCMR is closely
  coordinated with EPA's
  Contaminant Candidate List,
  or CCL. EPA uses both of
  these programs to identify
  drinking water contaminants
  of concern. Both programs
  focus on contaminants that
  are not currently regulated.

  EPA uses the best available
  information to decide which
  contaminants should be on
  the CCL, selecting
  unregulated contaminants of
  highest interest to EPA for
  further review. The CCL lists
  contaminants that may harm
  health, may occur in public
  water systems, and may
  require drinking water
  regulation. Some of the CCL
  contaminants require further
  research. This could include
  research on the following:

    What contaminants are in
    water and how often they
    occur.
    What methods are
    appropriate to detect
    contaminants.

    How contaminants affect
    health.
    How to remove
    contaminants from water.

  EPA uses the CCL as its
  primary source from which
  to select UCMR
  contaminants.  Priority is
  given to contaminants
  where testing methods are
  available and where little is
  known about how often the
  contaminant occurs  in
  drinking water.

  UCMR results can also
  inform CCL  priorities if
  UCMR contaminants are
  detected in drinking water,
  and if these contaminants
  are not on a current  CCL.
What Does UCMR2 Participation Involve? What Does It Cost?
Participating systems collect samples of drinking water  and have them tested for
UCMR contaminants. The largest water systems (serving more than 100,000 people)
are testing for all 25 UCMR2 contaminants. Water systems serving 10,001 to 100,000
people are testing for all 10 contaminants on List 1. Some of these systems are also
testing for the additional 15 contaminants  on  List 2.  Selected small  water systems
(serving 10,000 or fewer people) are testing for either List 1 or List 2 contaminants (but
not both). Large systems are paying their own testing costs ($190-$370 per sample, per
testing method,  on average). EPA is paying the testing costs  for small  systems and
managing the analysis of small system samples.

What Will  EPA Do With This Occurrence Information?
EPA will use this information on what contaminants are occurring in drinking water to
help decide which contaminants might need to be regulated. When deciding to regulate
a contaminant, EPA is required to consider the following:

• Whether the contaminant has the potential to harm human health.

• How often the contaminant occurs in public drinking water.

• Whether regulation presents a meaningful opportunity to reduce public health risks.

As a part of this process, EPA evaluates whether contaminants are occurring at levels
that could harm humans. UCMR data help EPA  to make  this decision by providing
information on how often, and at what levels, contaminants occur in drinking water.


What Does This Information Mean  to  Me?
Contaminant monitoring is part  of a  larger process  that EPA, States, Tribes, water
systems,  and other  partners use to  protect drinking  water.  Health information is
necessary to know whether  these contaminants  pose  a health risk,  but it  is  often
incomplete for unregulated contaminants and is frequently being studied at the same
time  UCMR monitoring is taking place. Some contaminants maybe  harmful at low
levels; others maybe harmful only at much higher levels. UCMR is a tool to find out
what is in the drinking water, but additional information is needed to know whether
these contaminants pose a health risk.

How Can I Find Out the Results?
If a water system is participating and finds contaminants in the drinking water,  they
will provide  the information to their customers in an annual water quality report (called
a  Consumer Confidence Report). This includes both regulated and unregulated
contaminants. Systems mail these reports directly to customers, and many reports are
available from EPA's Web site. EPA will also make the results available on-line via its
National  Contaminant Occurrence Database.  These  results  will be  posted on  an
ongoing basis after they have been reviewed for  quality.

How Can I Learn More?
• General information on  drinking   water is available  at  EPA's  drinking water
  Web site  (www.epa.gov/safewater)  or by calling the Safe Drinking Water hotline
  (800-426-4791).

• Additional information on UCMR is available  at  www.epa.gov/safewater/ucmr/
  index.html.
Office of Water
www.epa.gov/safewater
                                                               EPA815-F-08-010
                                                                 December 2008

-------