SPRINGFIELD – Illinois Environmental Protection Agency’s (Illinois EPA) Director James Jennings issued a statement following the U.S. EPA’s announcement to roll back protective national drinking water standards for Per- and Polyfluoroalkyl substances (PFAS) in community water supplies (CWS).
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“Illinois EPA has been working to address PFAS contamination in Illinois community water supplies since 2020,” said Director Jennings. “These efforts have included comprehensive water sampling and advocating for protective, scientifically sound, drinking water standards. Thankfully, our proactive efforts have led to the adoption of amendments to Illinois groundwater and drinking water regulations that safeguard Illinois communities. Regardless of the federal government’s actions, our commitment to address PFAS pollution and protect our drinking water resources remains.”
Background:
U.S. EPA initially established a federal Health Advisory for PFAS in 2016 but took no action to establish Maximum Contaminant Levels (MCLs), federal drinking water standards, until 2024. In the fall of 2020, Illinois EPA announced plans to conduct a statewide investigation into the prevalence and occurrence of PFAS in all CWS in Illinois. Data collected by the investigation was expected to be used in the development of state specific MCL standards for PFAS. In addition, in 2021, the Illinois EPA filed proposed amendments of the Illinois Pollution Control Board’s (Board) Part 620 groundwater quality regulations to preserve and protect Illinois groundwater and to ensure that the state’s groundwater quality standards match current scientific data and methodologies. The Illinois EPA’s proposal included new groundwater quality standards for six PFAS, (see chart below) based on the most recent scientific information available. In 2025, the Board’s amendments to Part 620 were adopted.
PFAS Analyte | Acronym | Class I Potable Resource (ppt = ng/L) |
Hexafluoropropylene oxide dimer acid (GenX) | PFDO-DA | 10 ppta |
Perfluorobutanesulfonic acid | PFBS | 2,000 ppta |
Perfluorohexanesulfonic acid | PFHxS | 10 ppta |
Perfluorononanoic acid | PFNA | 10 ppta |
Perfluorooctanoic acidb | PFOA | 4 ppta |
Perfluorooctanesulfonic acidb | PFOS | 4 ppta |
In April 2024, U.S. EPA finalized MCLs for specific PFAS (see chart below). In early 2026 the Board adopted identical-in-substance amendments to Illinois drinking water regulations.
U.S. EPA PFAS Maximum Contaminant Levels
Chemical | Maximum Contaminant Level Goal (MCLG) | Maximum Contaminant Level (MCL) |
PFOA | 0 | 4.0 ppt |
PFOS | 0 | 4.0 ppt |
PFNA | 10 ppt | 10 ppt |
PFHxS | 10 ppt | 10 ppt |
HFPO-DA (GenX chemicals) | 10 ppt | 10 ppt |
Mixture of two or more: PFNA, PFHxS, HFPO-DA, and PFBS | Hazard Index of 1 | Hazard Index of 1 |
Maximum Contaminant Level Goal (MCLG): The level of contaminant in drinking water below which there is no known or expected risk to health. MCLGs allow for a margin of safety and are non-enforceable public health goals. | ||
Illinois Community Water Supplies must monitor these PFAS in drinking water. The Board rules require:
- Initial monitoring completed - Deadline April 25, 2027
- Ongoing compliance monitoring - Begins April 26, 2027
- Compliance with MCLs - Begins April 26, 2029
Case details for this rulemaking can be found on the IPCB website by searching Case R2025-001 or R2025-009 (consolidated).
