First Unregulated Contaminant Monitoring Rule
You will need Adobe Reader to view some of the files on this page. See EPA’s About PDF page to learn more.The The 1996 Safe Drinking Water Act (SDWA) amendments require that once every five years EPA issue a new list of no more than 30 unregulated contaminants to be monitored by public water systems (PWSs). The first Unregulated Contaminant Monitoring Rule (UCMR 1) was published on September 17, 1999, and through supplemental actions on March 2, 2000, and January 11, 2001.
UCMR 1 required monitoring for 26 contaminants between 2001 and 2003 using analytical methods developed by EPA, consensus organizations, or both. This monitoring provides a basis for future regulatory actions to protect public health.
UCMR 1 contaminants
Assessment monitoring (List 1 contaminants)
All PWSs serving more than 10,000 people and 800 representative PWSs serving 10,000 or fewer people were required to monitor for 12 List 1 contaminants during a 12-month period from January 2001 through December 2003. The 12 contaminants were:
- 2,4-dinitrotoluene
- 2,6-dinitrotoluene
- Acetochlor
- DCPA mono-acid degradate
- DCPA di-acid degradate
- 4,4'-DDE
- EPTC
- Molinate
- MTBE
- Nitrobenzene
- Perchlorate
- Terbacil
Fact sheets for assessment monitoring of List 1 contaminants:
- UCMR 1 Monitoring for List 1 Contaminants by Large Public Water Systems
- UCMR 1 Monitoring for List 1 Contaminants by Selected Small Public Water Systems (PDF)(3 pp, 12 K)
- UCMR 1 Monitoring by Index Systems (PDF)(2 pp, 10 K)
Screening survey (List 2 contaminants)
All PWSs serving more than 100,000 people, 320 representative PWSs serving 10,001 to 100,000 people, and 480 representative PWSs serving 10,000 or fewer people were required to monitor for 13 List 2 contaminants during a 12-month period from January 2001 through December 2003. The 13 contaminants were:
- 1,2-diphenylhydrazine
- 2-methyl-phenol
- 2,4-dichlorophenol
- 2,4-dinitrophenol
- 2,4,6-trichlorophenol
- Diazinon
- Disulfoton
- Diuron
- Fonofos
- Linuron
- Nitrobenzene
- Prometon
- Terbufos
- Aeromonas
Fact sheets for the screening survey of List 2 contaminants:
- UCMR 1 Screening Survey for List 2 Contaminants by Selected Large Public Water Systems (PDF)(3 pp, 11.5 K)
- UCMR 1 Screening Survey for List 2 Contaminants by Selected Small Public Water Systems (PDF)(3 pp, 11.5 K)
- UCMR 1 Screening Survey for Aeromonas at Selected Public Water Systems (PDF)(2 pp, 9.8 K)
Federal Register Notices
On October 29, 2002, EPA published a final rule to approve EPA Method 1605 to monitor Aeromonas. The rule also specified that laboratories wishing to be approved for this method must participate in an Aeromonas proficiency testing (PT) program conducted by EPA.
On March 12, 2002, EPA published a rule to establish the electronic reporting date for monitoring results.
- Federal Register Notice: Unregulated Contaminant Monitoring Regulation for Public Water Systems; Establishment of Reporting Date (Page 11071-11072)
- Federal Register Notice: Unregulated Contaminant Monitoring Regulation for Public Water Systems; Establishment of Reporting Date (Page 11043-11046)
On March 7, 2002, EPA published a proposed rule to approve EPA Method 1605 to monitor Aeromonas.
On September 4, 2001, EPA published a direct final rule to amend the List 2 requirements and delay the requirements for the electronic reporting of monitoring results.
- Federal Register Notice: Unregulated Contaminant Monitoring Regulation for Public Water Systems; Amendment to the List 2 Rule and Partial Delay of Reporting of Monitoring Results
On January 11, 2001, EPA published analytical methods for several screening survey List 2 contaminants and described the required monitoring for those contaminants. In this notice, EPA also modified the UCMR to improve the implementation of monitoring for both List 1 and List 2 contaminants.
- Federal Register Notice: Revisions to the Unregulated Contaminant Monitoring Regulation for Public Water Systems; Final Rule
- Federal Register Notice: Unregulated Contaminant Monitoring Regulation for Public Water Systems; Analytical Methods for List 2 Contaminants; Clarifications to the Unregulated Contaminant Monitoring Regulation
- Federal Register Notice: Unregulated Contaminant Monitoring Regulation for Public Water Systems; Analytical Methods for List 2 Contaminants and Clarifications; Proposed Rule
On March 2, 2000, EPA published a rule specifying the approved analytical methods for perchlorate and acetochlor. EPA included a notice about a laboratory approval process for laboratories interested in participating in perchlorate monitoring.
- Federal Register Notice: Unregulated Contaminant Monitoring Regulation for Public Water Systems: Analytical Methods for Perchlorate and Acetochlor; Announcement of Laboratory Approval and Performance Testing (PT) Program for the Analysis of Perchlorate; Final Rule and Proposed Rule - Part 1
- Federal Register Notice: Unregulated Contaminant Monitoring Regulation for Public Water Systems: Analytical Methods for Perchlorate and Acetochlor; Announcement of Laboratory Approval and Performance Testing (PT) Program for the Analysis of Perchlorate; Final Rule and Proposed Rule - Part 2
On January 8, 1999, EPA published a rule suspending unregulated contaminant monitoring for small public water systems.