Skip to Content
Main Content

PFAS: EPA to require all public water systems to sample 29 analytes beginning in 2023

March 14, 2022

PFAS: EPA to require all public water systems to sample 29 analytes beginning in 2023

March 14, 2022

Authored By


Co-authored by Taryn McKnight, PFAS Practice Group Leader for Eurofins Environment Testing America

Wisconsin public water system operators will soon be required to evaluate their systems for the presence of the two most-studied PFAS analytes - perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) - under state law. In addition, Wisconsin municipalities are receiving mandatory directives from the U.S. government to evaluate a broader list of per- and polyfluoroalkyl substances (PFAS) in drinking water.

On Dec. 27, 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 Wisconsin 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.

While Wisconsin law will soon require the limited evaluation of PFOA and PFOS and adherence to the current EPA Lifetime Health Advisory Limit set in 2016 of 70 parts per trillion, the question of which communities are drinking PFAS in Wisconsin will be definitively answered by UCMR 5.

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. As of January 2022, the EPA published a list of thirteen labs approved to support both methods 533 and 537.1. This list may grow as laboratories may seek approval to participate in UCMR 5 until August 1, 2022.

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 a 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 Jan. 1, 2023, and must end by as late as Dec. 31, 2025. Large public water supplies servicing greater than 10,000 are eligible to modify this schedule.

EPA takes lead role

While all 29 of the PFAS selected for UCMR 5 are currently included on the Wisconsin Department of Natural Resources’ (DNR's) PFAS List of 33 PFAS analytes, the DNR, including its policy-setting Natural Resources Board (NRB), do not have an active role in administering UCMR 5 requirements or compliance. Public water systems are tasked with directly reporting results to the EPA.

Groundwater setback delays the inevitable

While the first attempt to promulgate a groundwater rule based on Department of Health Services’ (DHS') recommended standards for PFOA and PFOS failed to pass NRB, DNR remains statutorily obligated to promulgate rules for contaminants based on public health recommendations from DHS in Wis. Stat. chapter 160. On June 23, 2021, NRB approved two scope statements for additional PFAS rules. For PFOA and PFOS, DNR may elect to either start the process over again for all the Cycle 10 contaminants, or they may elect to revise their 2021 scope statements to add PFOA and PFOS using the process under Wis. Stat. section 227.135(4). Both options have drawbacks.

The 12 PFAS analytes included in the new respective groundwater and drinking water rules are each included in EPA’s UCMR 5 list. DNR must promulgate these rules by June 2024, or the scope statement shall expire.

Upcoming Events:

Godfrey & Kahn Shareholder, Ned Witte, will be speaking at the 2022 Global EnviroSummit. His presentation is titled, “Legal Perspective on PFAS Liability.”

Learn more

Join Our Mailing List

Need to stay current on the latest news, trends and regulatory issues impacting your business? Subscribe today! We know your time is valuable, so we limit our communications to only the most pertinent info you need to stay informed.