EPA uses the Unregulated Contaminant Monitoring Rule (UCMR) to collect data for contaminants that are suspected to be present in drinking water and do not have health-based standards set under the Safe Drinking Water Act (SDWA).
The SDWA Amendments of 1996 provide for:
- Monitoring no more than 30 contaminants every five years
- Monitoring large systems and a representative sample of small public water systems serving less than 10,000 people
- Storing analytical results in a National Contaminant Occurrence Database (NCOD)
EPA’s selection of contaminants for a particular UCMR cycle is largely based on a review of the Contaminant Candidate List (CCL).
EPA pays for the analysis of all samples from systems serving 10,000 or fewer people.
EPA coordinates an approval program for laboratories that wish to analyze public water system samples.
- Why was the UCMR program developed?
Occurrence data are collected through UCMR to support the Administrator's determination of whether to regulate particular contaminants in the interest of protecting public health.
The UCMR program was developed in coordination with the CCL.The CCL is a list of contaminants that:
- Are not regulated by the National Primary Drinking Water Regulations
- Are known or anticipated to occur at public water systems
- May warrant regulation under the SDWA
- How does EPA select the contaminants for UCMR?
EPA reviews contaminants that had been evaluated through existing prioritization processes, including previous UCMR contaminants and the CCL. Additional contaminants may be identified based on current research on occurrence and health effect risk factors.
Chemicals that are not registered for use in the United States, do not have an analytical reference standard, or do not have an analytical method ready for use are generally removed from consideration.
EPA further prioritizes remaining contaminants based on more extensive health effects evaluations, typically performed by the Office of Water’s Office of Science and Technology. The procedures for evaluating health effects were developed to support the ranking of contaminants for future CCLs.
- What are the public health benefits of UCMR?
UCMR provides EPA and others with scientifically valid data on the occurrence of these contaminants in drinking water. This permits assessment of the population being exposed and the levels of exposure.
This data set is one of the primary sources of occurrence and exposure information the Agency uses to develop regulatory decisions for emerging contaminants.
Rounds 1 and 2 Datasets for the Unregulated Contaminant Monitoring Program Managed by State Drinking Water Programs
State drinking water programs managed the original unregulated contaminant monitoring program that applied to public water systems (PWSs) serving more than 500 people.
The Round 1 dataset contains PWS monitoring results for 62 then-unregulated contaminants. These data were collected from 40 states and primacy entities between 1988 and 1992.
The Round 2 dataset contains PWS monitoring data for 48 then-unregulated contaminants. These data were collected from 35 states and primacy entities between 1993 and 1997.
First Unregulated Contaminant Monitoring Rule
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.
Second Unregulated Contaminant Monitoring Rule
The second Unregulated Contaminant Monitoring Rule (UCMR 2) was published on January 4, 2007. UCMR 2 required monitoring for 25 contaminants between 2008 and 2010 using analytical methods developed by EPA, consensus organizations, or both. This monitoring provides a basis for future regulatory actions to protect public health.
Third Unregulated Contaminant Monitoring Rule
The third Unregulated Contaminant Monitoring Rule (UCMR 3) was published on May 2, 2012. UCMR 3 requires monitoring for 30 contaminants (28 chemicals and two viruses) between 2013 and 2015 using analytical methods developed by EPA, consensus organizations or both. This monitoring provides a basis for future regulatory actions to protect public health.
Fourth Unregulated Contaminant Monitoring Rule
The fourth Unregulated Contaminant Monitoring Rule (UCMR 4) was proposed on December 11, 2015. The proposal outlines monitoring for 30 chemical contaminants between 2018 and 2020 using analytical methods developed by EPA and consensus organizations. This monitoring provides a basis for future regulatory determinations and, as warranted, actions to protect public health.
In The News:
EPA STATEMENT ON CHROMIUM IN DRINKING WATER
Ensuring safe drinking water for all Americans is a top priority for EPA. The agency has taken many actions to improve information on chromium and its potential health risks in drinking water. EPA and states are responsible for ensuring that public water systems are in compliance with the current standard for total chromium. The agency has also collected nationally representative data on the occurrence of both total chromium and hexavalent chromium through the third Unregulated Contaminant Monitoring Rule (UCMR3). EPA is actively working on the development of the Integrated Risk Information System (IRIS) assessment of hexavalent chromium, which will include a comprehensive evaluation of potential health effects associated with hexavalent chromium, and EPA expects that the draft IRIS assessment will be released for public comment in 2017. Under the Safe Drinking Water Act, before EPA can decide whether to regulate a contaminant, it must meet three criteria:
- The contaminant may have an adverse effect on the health of persons;
- is known to occur or there is a substantial likelihood that the contaminant will occur in public water systems with a frequency and at levels of public health concern; and
- in the sole judgment of the EPA Administrator, the regulation of the contaminant presents a meaningful opportunity for health risk reductions for persons served by public water systems.
EPA has a drinking water standard of 0.1 milligrams per liter (mg/l) or 100 parts per billion (ppb) for total chromium. This includes all forms of chromium, including hexavalent chromium. Only one of the almost 5,000 public water systems that monitored total chromium under the UCMR3 reported results that exceeded EPA’s standard. The State of California has promulgated an enforceable maximum contaminant level of 0.01 mg/l or 10 ppb for hexavalent chromium. While this standard only applies to water systems in California, less than 2 percent of the UCMR3 systems nationally reported hexavalent chromium at levels exceeding this standard.
For more information please visit EPA's IRIS website for hexavalent chromium:
FACT SHEET ON FLUORINATED ORGANIC CHEMICALS (PFOA & PFOS) IN DRINKING WATER
PFOA and PFOS are fluorinated organic chemicals that are part of a larger group of chemicals referred to as perfluoroalkyl substances (PFASs). PFOA and PFOS have been the most extensively produced and studied of these chemicals. They have been used to make carpets, clothing, fabrics for furniture, paper packaging for food and other materials (e.g., cookware) that are resistant to water, grease or stains. They are also used for firefighting at air-fields and in a number of industrial processes.
To view EPA's Fact Sheet please click here: Fact Sheet - PFOA & PFOS Drinking Water Health Advisories