Skip common site navigation and headers
United States Environmental Protection Agency
Unregulated Contaminant Monitoring Program
Begin Hierarchical Links EPA Home > Water > Ground Water & Drinking Water > Unregulated Contaminant Monitoring Program End Hierarchical Links



Related Links

National Contaminant Occurrence Database

Contaminant Candidate List

EPA uses the Unregulated Contaminant Monitoring (UCM) program to collect data for contaminants suspected to be present in drinking water, but that do not have health-based standards set under the Safe Drinking Water Act (SDWA). Every five years EPA reviews the list of contaminants, largely based on the Contaminant Candidate List. The SDWA Amendments of 1996 provide for:

  • Monitoring no more than 30 contaminants per 5-year cycle
  • Monitoring only a representative sample of public water systems serving less than 10,000 people
  • Storing analytical results in a National Contaminant Occurrence Database (NCOD)

The UCM program progressed in several stages. Currently, EPA manages the program directly as specified in the Unregulated Contaminant Monitoring Regulation (UCMR).

  • Stakeholder Meeting Regarding Revisions to the Unregulated Contaminant Monitoring Regulation HTML | PDF Version (1pp, 44K, About PDF)

The history of the UCM program includes:

  • UCM Rounds 1 & 2 (1988-1997): State drinking water programs managed the original program and required public water systems (PWSs) serving more than 500 people to monitor contaminants.
  • UCMR 1 (2001-2005): the SDWA Admendments of 1996 redesigned the UCM program to incorporate a tiered monitoring approach. The rule required all large PWS and a nationally representative sample of small PWSs serving less than 10,000 people to monitor the contaminants.
  • UCMR 2 (2007-2010): EPA manages the second monitoring cycle. This monitoring cycle establishes a new set of unregulated contaminants.


  • UCM Rounds 1 & 2 - Background information, occurrence data and complete reports on occurrence data analyses
  • UCMR 1 - Regulatory history, guidance and initial occurrence data
  • UCMR 2 - Final rule, including the list of contaminants and methods for monitoring, and guidance for PWS monitoring and reporting requirements
  • Occurrence Data - UCMR data from all rounds of monitoring
  • UCMR Updates - Information for utilities and laboratories participating in monitoring


Safewater Home | About Our Office | Publications | Calendar | Links | Office of Water | En Español

Begin Site Footer

EPA Home | Privacy and Security Notice | Contact Us