United States Office of Water ' EPA 815-F-01-003/3
Environmental Protection 4606 January 2001
Agency
Unregulated Contaminant
Monitoring Regulation:
Monitoring for List 1
Contaminants by Large
Public Water Systems
Introduction
The Safe Drinking Water Act (SDWA) requires community water systems (CWSs) and non-transient, non-community water
systems (NTNCWSs) that serve more than 10,000 persons (large systems) to monitor their water for the presence of
unregulated contaminants. The purpose of this monitoring is to collect data to support the U.S. Environmental Protection
Agency (EPA) Administrator's decisions regarding whether or not to regulate contaminants such as those on the Drinking
Water Contaminant Candidate List to protect public health.
m/il? requirement the U.S. EPA promulgated revisions to the Unregulated Contaminant Monitoring Regulations
(UCMR). Published on September 17, 1999, and supplemented on March 2, 2000 and January 11, 2001, the UCMR
SpCClIlGS!
Which public water systems (PWSs) must monitor
How a randomly selected sample set of small PWSs will be chosen to monitor
Which contaminants systems must monitor
When, where, and how often samples must be taken
Which laboratory methods are to be used for analyzing the samples
What quality control procedures, in addition to those in the laboratory methods, must be followed
What the requirements are for reporting the results of the monitoring
What roles the States and Indian Tribes will play in implementing the monitoring program.
EPA has organized the contaminants on the UCMR (1999) List into three lists based on the availability of analytical methods
to detect their presence in drinking water and the type of monitoring to be conducted: List 1, Assessment Monitoring
consists ot 12 chemical contaminants for which standard analytical methods are available; List 2, Screening Survey consists
ol 16 contaminants for which new analytical methods will be used; and List 3, Pre-Screen Testing consists of 9
contaminants for which analytical methods are being researched. This fact sheet is concerned with List 1, Assessment
Monitoring. Table 1 on the next page identifies the List 1 contaminants and their uses or environmental sources.
What Systems Must Monitor for List 1 Contaminants? (See §141.40(a)(l))
All large community and non-transient, non-community water systems that do not purchase all of their water from another •
system must conduct monitoring. Large systems serve more than 10,000 persons. If you are unsure of your status as a
PWb, contact your State drinking water administrator or your EPA regional contact.
When and How Often Must Monitoring Occur? (See §141.40(a)(5))
The effective implementation date of the Assessment Monitoring requirement is January 1, 2001. Large systems must
conduct Assessment Monitoring during any continuous 12-month period from January 1, 2001 to December 31 2003 (See
1 able 2, below, for details.) At least one sample must be taken during a time when the water system is vulnerable to
contammfltinn
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Table 1: UCMR (1999) List 1 Contaminants and Their Uses or Sources
Contaminant
2,4-dinitrotoluene
2,6-dinttrotoluene
Acetochlor
DCPA mono acid;
DCPA di acid
4.4'-DDE
EPIC
Molinate
MTBE
Nitrobenzene
Perchlorate
Terbacil
CASRN
121-14-2
606-20-2
34256-82-1
887-54-7;
2136-79-0
72-55-9
759-94-4
2212-67-1
1634-04-4
98-95-3
14797-73-0
5902-51-2
Use or Environmental Source
Used in the production of isocyanate and explosives
Used as a mixture with 2,4-dinitrotoluene (similar uses)
Herbicide used with cabbage, citrus, coffee, and corn crops
Degradation products of DCPA, an herbicide used on grasses and weeds with fruit and vegetable
crops. Both the DCPA degradates are measured and reported as a single analyte
Degradation product of DDT, a general insecticide
Herbicide used on annual grasses, weeds, in potatoes and corn
Selective herbicide used with rice, controls watergrass
Octane enhancer in unleaded gasoline
Used in the production of aniline, which is used to make dyes, herbicides, and drugs
Oxygen additive in solid fuel propellant for rockets, missiles, and fireworks
Herbicide used with sugarcane, alfalfa, and some fruit, etc.
From Where Must Samples be Taken? (See §141.40(a)(5))
Samples to be analyzed for the presence of unregulated chemical contaminants must be taken at the entry points to the
distribution system, such as the representative Phase n/V sampling points specified by the State, unless otherwise directed by
the State or EPA. If your State requires source water monitoring, inquire with your State or EPA drinking water program
contact for further guidance.
Table 2: Assessment Monitoring by Type of Water Source
Source Water Type
Surface Water
Ground Water
Assessment Monitoring Frequency
Four quarterly samples, taken as follows: Select either the first, second, or third month of a quarter
and sample in that same month of each of four consecutive quarters1 to ensure that one of these
sampling events occurs during the vulnerable time2
Two times in a year, taken as follows: Sample during one month of the most vulnerable time2 and
during one month five-to-seven months earlier or later3
1 "Select either the first, second, or third month of a quarter and sample in that same month of each of four consecutive quarters" means
that you must monitor during each of the four months of either: January, April, July, October; February, May, August, November; or
March, June, September, December.
2 "Vulnerable time" means May 1 through July 31 , unless the State or EPA informs you that it has selected a different period for sampling
as your system's vulnerable time.
3 "Sample during one month of the vulnerable time and during one month five-to-seven months earlier or later" means, for example that if
you select May as your 'Vulnerable time" month to sample, then one month five to seven months earlier would be October, November or
December of the preceding year, and one month five to seven months later would be either October, November or December of the
same year.
How Are the Samples to be Analyzed? (See §141.40(a)(5) and Appendix A)
Samples are to be analyzed by State- or primacy agency- certified drinking water compliance monitoring laboratories, using
methods according to the UCMR's quality control (QC) specifications. (For details, see the Unregulated Contaminant
Monitoring Regulation Analytical Methods and Quality Control Manual [EPA 815-R-00-006] and its supplements.) Note
that it is the water systems' responsibility to use State- or primacy agency- certified laboratories that employ the correct
methods. If analyzing samples for perchlorate under the UCMR, labs are required to successfully participate in a special
performance testing program (§141.40(a)(5)).
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Table 3: UCMR Data Elements for Reporting Sample Results
Public Water System (PWS) Identification Number
PWS Facility Identification Number — Identification
Number and Sampling Point Type Identification
Sample Collection Date
Sample Identification Number
Contaminant/Parameter
Analytical Results — Sign
Analytical Results -Value
Analytical Results - Unit of Measure
Analytical Method Number
Sample Analysis Type
Sample Batch Identification Number
Minimum Reporting Level
Minimum Reporting Level Unit of Measure
Analytical Precision
Analytical Accuracy
Spiking Concentration
What Data Must be Reported to
EPA? (See §141.35(d))
Analytical results that are reported
must include the UCMR Data
Elements listed in Table 3, at right.
Many of these are QC measures
and should be provided by the
laboratory.
How Are the Monitoring Data to
be Reported to EPA? (See
§141.35(e))
The PWS has several options for
reporting monitoring data to EPA.
It can instruct the laboratory that
analyzed its samples to enter the
results directly into the electronic
template that the Agency will make
available on the Office of Ground
Water and Drinking Water Homepage on the World Wide Web. (EPA is developing several options for the electronic
reporting by laboratories, including a web interface where data can be keyed in and the capability to upload data in batches
using standard flat-file or XML formats. Further guidance and tutorials will be available soon.) The PWS can then review the
results on-line and electronically indicate its approval to submit the data to EPA. As an alternative, a PWS can require that
the laboratory receive its approval before posting analytical data on the EPA electronic reporting system. If the PWS
determines that the laboratory lacks either the capability to report electronically to EPA or to provide data to the system prior
to their submission to EPA without rekeying, the PWS may ask EPA whether an alternate reporting format may be used.
The PWS also must submit the results to the State.
Are There Requirements for Notifying the Public?
Yes. Under the Consumer Confidence Report (CCR) Rule, as specified in 40 CFR §141.153(d), CWSs must report the
monitoring results whenever unregulated contaminants are detected. CCRs are to be sent to all billing customers each year by
July 1. (The CCR Rule does not apply to non-community water systems.) In addition, the Public Notification Rule (40 CFR
§141.207), published on May 4, 2000 (65 FR 25981), requires PWSs to notify the public annually that the results of
monitoring for unregulated contaminants are available. Therefore, CWSs and NTNCWSs must provide public notice if they
are required to monitor for unregulated contaminants. Details on these reporting requirements can be found in the documents
Preparing Your Drinking Water Consumer Confidence Report (EPA 816-R-99-002) and Public Notification Handbook
(EPA 816-R-00-010). Both are available on the Web at www.epa.gov/safewater.
Where Can I Get More Information?
More information on the UCMR is available from the following sources:
• Federal Register notices of September 17, 1999 (64 FR 50556),
March 2, 2000 (65 FR 11372), and January 11, 2001 (66 FR
2273).
• The EPA Office of Ground Water and Drinking Water Web Site
(www.epa.gov/safewater/ucmr.html).
• Unregulated Contaminant Monitoring Regulation Analytical •
Methods and Quality Control Manual (EPA 815-R-00-006).
° Supplement A to the Unregulated Contaminant Monitoring
Regulation Analytical Methods and Quality Control Manual
(EPA 815-R-00-002).
° The Safe Drinking Water Hotline (800 426-4791).
EPA is developing additional guidance materials, so check the Office of
Ground Water and Drinking Water Web Site often for the latest
information about them.
Table 4, at right, lists UCMR contacts in the EPA regional offices and the
Agency's Technical Support Center in Cincinnati, OH.
Table 4: EPA UCMR Contacts
Region
Region 1
Region 2
Region 3
Region 4
Region 5
Region 6
Region 7
Region 8
Region 9
Region 10
Technical
Support
Center
Contact
Chris Ryan
Robert Poon
Michelle Hoover
Janine Morris
Janet Kuefler
Andrew J. Waite
Stan Calow
Rod Glebe
Jill Korte
Gene Taylor
Dan Hautman
Telephone
617918-1567
212637-3821
215814-5258
404 562-9480
312 886-0123
214 665-7332
913551-7410
303 312-6627
415744-1853
206553-1389
513569-7948
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