Water Quality Unregulated Contaminant Monitoring Rule
EPA to require all public water systems to sample 29 analytes beginning in 2023
The City of Pendleton Water Division will soon be required to evaluate their system for the presence of the two most-studied PFAS analytes – perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) – under state law.
On December 27th, 2021, the U.S. Environmental Protection Agency (EPA) published the fifth Unregulated Contaminant Monitoring Rule (UCMR 5) which requires all public water systems that serve more than 10,000 people to sample and analyze for the presence of 29 PFAS and the heavy metal, lithium, in a set interval between 2023 and 2025. The sampling program must take place over a 12-month period. Most systems will be required to share with the EPA a set of four quarterly samples. Sampling results will be subject to Oregon Public Records Laws and compiled by the EPA to be summarized in a report for publication in 2026.
GREATER SCOPE
UCMR testing is a requirement of the Clean Drinking Water Act. Previous UCMR testing that included certain PFAS was conducted in 2013 to 2015 under UCMR 3. Unlike UCMR 3, which required systems serving greater than 10,000 people to sample for six PFAS analytes, UCMR 5 applies to all public water systems that serve more than 3,300 people. This effort will also include a nationally representative sampling of systems serving fewer than 3,300 people. Another expansion in UCMR 5 is the inclusion of 29 PFAS and at reporting limits much lower than previously applied in UCMR 3.
ADVANCEMENTS IN TEST METHODOLOGY
UCMR 5 specifically requires the use of EPA’s newest drinking water method, 533 for 25 PFAS, as well as the older EPA method that was used during UCMR 3. Method 537.1 is required for the remaining four PFAS that are not captured by 533. The minimum reporting levels (MRLs) are set at 2-5 ppt for most compounds, with the highest limit at 20 ppt. This contrasts with UCMR 3 with MRLs of 10-90 ppt for the six PFAS. The EPA oversees the laboratory approval program for UCMR testing.
SAMPLING FREQUENCY
The drinking water source controls the sampling frequency for the required 12-month evaluation. For public water systems that primarily source their drinking water from surface water sources, four sampling events must take place, three months apart, over one-year period. For public water systems that source their drinking water from groundwater, sampling must take place twice over a one-year period (two total sampling events, separated by five to seven months).
POTENTIAL SCHEDULE FLEXIBILITY
The UCMR 5 cycle begins in January 2022 and ends in December 2026. The rule specifies sample collection may begin as early as January 1st, 2022, and must end by as late as December 31st, 2025. Large public water supplies servicing greater than 10,000 are eligible to modify this schedule.
EPA TAKES LEAD ROLE
Public water systems are tasked with directly reporting results to the EPA.
DEFINITIONS:
PFAS: Per- and polyfluoroalkyl substances (PFAS) are a large, complex group of manufactured chemicals that are ingredients in various everyday products
UCMR: The Unregulated Contaminant Monitoring Rule (UCMR) provides the U.S. Environmental Protection Agency (EPA) and other interested parties with scientifically valid data on the occurrence of contaminants suspected to be present in drinking water, but that do not have health-based standards set under the Safe Drinking Water Act (SDWA). he purpose of UCMR is to collect data from across the country on contaminants that may be present in drinking water.
