THE UNREGULATED CONTAMINANT MONITORING RULE (UCMR)
Home / PFAS Regulations / UCMR
Since 2001 Pace® has analyzed tens of thousands of samples as it participated in every round of US EPA’s Unregulated Contaminant Monitoring Rule (UCMR) drinking water monitoring program. As US EPA has issued its UCMR 6 proposal , we’re pleased to share insights and observations from our work with public water systems across the country.
WHAT IS UCMR 6?
The United States Environmental Protection Agency’s (EPA) Unregulated Contaminant Monitoring Rule (UCMR) is designed to collect data on contaminants suspected to be present in drinking water but that do not yet have health-based standards set under the Safe Drinking Water Act (SDWA). A revised list of up to 30 contaminants is selected every five years. UCMR 6 is the sixth UCMR round to be implemented and is proposed to include testing requirements for Ultrashort-Chain PFAS/Organofluorine Compounds, Pesticides, Semi-VOCs, and VOCs.
WHAT IS THE STATUS OF US EPA’S UCMR 6 PROPOSAL?
EPA issued the proposal on July 1, 2026 for public comment. EPA will review those comments, do additional review, and finalize the Rule by the end of 2026. The following sections will be applicable if the proposal remains unchanged.
WHAT CONTAMINANTS WERE NOT INCLUDED IN THE UCMR 6 PROPOSAL?
Most notably Microplastics. Numerous states formally requested that it be included as well as other organizations. EPA’s rationale for its exclusion was based on the timeline required for test method development by EPA that would not meet the mandatory schedule required to implement UCMR 6.
GET THE DETAILS ON UCMR 6
Sampling for UCMR 6 will take place between 2028 and 2030.Water systems should start their preparations by reaching out to Pace® for budgetary estimates. DOES MY WATER SYSTEM NEED TO COMPLY?
All public water systems serving 3,300 or more people and 800 smaller systems, randomly selected by the EPA, are required to comply with UCMR 6. This represents more than 10,000 water systems.
WHAT DO WE NEED TO SAMPLE?
For UCMR 6, sampling is only required at the Entry Point To The Distribution System (EPTDS) and does not include distribution system locations. Sampling of source water is not required in UCMR 6; however, the sampling schedule is driven by drinking water sources. For example, groundwater systems are required to sample semi-annually during their EPA-assigned 12-month sampling schedule. Surface water and Groundwater Under the Direct Influence (GWUDI) systems are required to sample quarterly during their EPA-assigned 12-month sampling schedule. Public water system operators should always check their EPA-assigned schedule and sampling requirements in the CDX SDAWRS system to ensure full compliance with each round of UCMR.
CAN PACE® PROVIDE UCMR SAMPLING SERVICES?
WHICH TEST METHODS ARE REQUIRED?
If the UCMR 6 proposal remains unchanged it will require analysis by four EPA validated test methods for 30 contaminants. Those methods include seven VOCs by EPA 524.3, thirteen Semi-VOCs by EPA 525.3, three Pesticides by EPA 540, and seven Ultrashort-Chain PFAS and Organofluorine Compounds by EPA 563.
DO I NEED TO USE A UCMR 6 LAB?
Since the UCMR contaminants vary cycle to cycle, the EPA approves UCMR testing laboratories for each new round of UCMR. All UCMR 6 testing must be done by an EPA UCMR 6 approved laboratory. EPA’s laboratory approval process requires an extensive application, passing of Proficiency Testing samples, and a successful upload of results into the CDX SDAWRS system.
ARE PRIVATE WELLS INCLUDED IN UCMR 6?
No. UCMR 6 only covers public water systems that serve 3,300 of more consumers and a set of 800 randomly selected smaller systems. However, in locations where PFAS and other chemicals listed in UCMR 6 are suspected , many private well owners may want to voluntarily test. Some states have set aside budgetary support for these private well owners, and federal dollars are available through grants to the states for disadvantaged communities.
HOW MUCH DOES TESTING COST?
A NATIONALLY RECOGNIZED LEADER IN UCMR TESTING
The Pace® UCMR team is nationally recognized and is often invited to present at water utility conferences across the country. In addition to being approved for UCMR, Pace® maintains all required certifications in every state and US territory for the analysis of drinking water and compliance monitoring of regulated contaminants. Pace® can also assist water systems in setting up their Safe Drinking Water Accession and Review System (SDWARS) accounts.Additional UCMR FAQs
Q: How can I find a UCMR drinking water laboratory?
Pace® operates EPA and state-approved laboratories across the country and several are in the process of applying for US EPA UCMR 6 approval.
Q: Where can I find results from UCMR 5 drinking water sampling?
Occurrence data from UCMR 5 drinking water sampling is available on the EPA’s dedicated UCMR 5 Data Finder webpage. This site provides updated national occurrence data summaries and detailed monitoring results reported by public water systems. The EPA website also offers downloadable data files and interactive dashboards, allowing you to search for results by contaminant, water system, or location. For more in-depth analysis, summary reports and technical documents related to UCMR 5 are made available alongside the raw sampling data on the EPA’s Unregulated Contaminant Monitoring Rule site.
Q: Does UCMR set enforceable limits on contaminants in drinking water?
UCMR does not set enforceable limits, but instead, requires public water systems to monitor and report concentrations of individual emerging contaminants in drinking water, supplying the EPA with comprehensive occurrence data to guide regulatory decision-making. When the EPA determines a contaminant should be regulated based on the evidence gathered through UCMR monitoring and other sources, it can establish legally enforceable Maximum Contaminant Levels (MCLs) under the National Primary Drinking Water Regulations (NPDWR).
Q: Will UCMR 6 include additional PFAS?
Yes, UCMR 6 includes seven Ultrashort-Chain (USC) PFAS/Organofluorine Compounds by EPA 563, a method developed by EPA in 2026. These USC chemicals are not detectable by EPA 537.1 or 533. EPA expects that 80% of all UCMR 6 samples analyzed by EPA 563 will detect one or more USC chemicals. This will require analysis of nearly all Field Reagent Blanks, nearly doubling the cost of analysis. This will also require water systems to report these detections in their Consumer Confidence Reports.
Q: What other contaminants are required for UCMR 6?
Seven Volatile Organic Compounds by EPA 524.3, thirteen Semi-Volatile Organic Compounds by EPA 525.3, and three Pesticide Metabolites by EPA 540. With the seven USC PFAS/Organofluorine Compounds this brings the total number of contaminants required by UCMR 6 to thirty, which is the maximum number of contaminants EPA may include in a round of UCMR.
Q: What is the first deadline that water systems must meet for UCMR 6?
Water systems should contact UCMR@pacelabs.com now to request their budgetary estimates for fiscal planning cycles. The first EPA-set deadline is December 31, 2027 by which time water systems must establish a CDX/SDWARS 6 account and complete required info therein, e.g., sample locations and IDs. Since nearly all participating systems also participated in UCMR 5, this process should be effectively the same. Subsequent deadlines will be set in each water system’s sampling schedules assigned by EPA in SDWARS. EPA will post all sampling schedules by month and year in SDWARS during 2027 and those deadlines must be met on any day in the scheduled months such that the laboratory receives samples on a weekday.
Q: Are water systems allowed to make changes to their EPA-assigned sampling schedules?
Yes, prior to December 31, 2027 systems may change their schedule within their SDWARS 6 account. After that EPA-set deadline systems must contact the UCMR coordinator to request changes at UCMR_Sampling_Coordinator@epa.gov.
REASONS TO CHOOSE PACE®
EXPERIENCED
Pace® has been an industry leader in persistent organic pollutant testing for over three decades.
CERTIFIED
We’re certified/accredited by NELAC, ISO, DOD, DOE, and in every state with a PFAS lab certification program.
RELIABLE
For emergencies, our Rapid Response Team can provide defensible results in as little as 24 hours.
COMMITTED
We are committed to helping our customers advance their important work through building strong relationships, delivering upon expectations, and providing exceptional customer service.
ADVANCED
We can test for PFAS in both solid and aqueous matrices, including potable and non-potable waters, soils, and biota.
INNOVATIVE
We’re on the leading edge of science, working with EPA, DOD, ASTM, and others to develop new methods for analyzing PFAS.
