First Unregulated Contaminant Monitoring Rule
Access Results
The Safe Drinking Water Act (SDWA) requires that once every five years the EPA issue a list of 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 2005 using analytical methods developed by the EPA and consensus organizations. This monitoring provides a basis for future actions to protect public health.
UCMR 1 Scope, Analytical Methods, and Contaminants
Assessment Monitoring (AM)
All PWSs serving more than 10,000 people and 800 representative PWSs serving 10,000 or fewer people were required to monitor for 12 contaminants during a 12-month period from January 2001 through December 2005.
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:
- UCMR 1 Monitoring by Large PWSs
- UCMR 1 Monitoring by Selected Small PWSs (PDF)(3 pp, 12 K)
- UCMR 1 Monitoring by Index PWSs (PDF)(2 pp, 10 K)
Screening Survey (SS)
PWSs monitored during a 12-month period from January 2001 through December 2003. The EPA randomly selected PWSs from those PWSs that were required to conduct AM. A set of 300 representative PWSs monitored for the 12 chemical contaminants on the SS and a different set of 300 representative PWSs monitored for Aeromonas.
The 14 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:
- UCMR 1 Screening Survey by Selected Large PWSs (PDF)(3 pp, 11.5 K)
- UCMR 1 Screening Survey by Selected Small PWSs (PDF)(3 pp, 11.5 K)
- UCMR 1 Screening Survey for Aeromonas at Selected PWSs (PDF)(2 pp, 9.8 K)
The EPA paid all analytical costs associated with monitoring at PWSs serving 10,000 or fewer people.
Federal Register Notices
On October 29, 2002, the 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 the EPA.
On March 12, 2002, the 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, the EPA published a proposed rule to approve EPA Method 1605 to monitor Aeromonas.
On September 4, 2001, the 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, the EPA published analytical methods for several Screening Survey List 2 contaminants and described the required monitoring for those contaminants. In this notice, the 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, the EPA published a rule specifying the approved analytical methods for perchlorate and acetochlor. The 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 PWSs.