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PFAS Statewide Health Advisory
A Health Advisory is a regulatory action that provides guidance to local officials and community water supply operators in protecting the health of water consumers. Illinois EPA is authorized to issue a Health Advisory when there is a confirmed detection in a community water supply well of a chemical substance for which no numeric groundwater standard exists. Illinois EPA has two Statewide Health Advisories in effect for individual PFAS confirmed in community water supply wells as a result of sampling investigations of community water supply wells.
Health Advisories serve several purposes as outlined in 35 Ill. Adm. Code 620.601(a) – (d). Health Advisories are to be used by the Illinois EPA when:
- evaluating groundwater cleanup;
- developing future rulemaking proposals;
- evaluating mixtures of chemical substances; and
- determining whether a community water supply is taking its raw water from a site or source consistent with regulatory requirements.
In addition to the uses outlined in the regulations, the Health Advisories also contain general information on the characteristics of the harmful contaminant, potential adverse health effects and numerical contaminant guidance levels. The health-based guidance levels (HBGLs) contained in the Health Advisories represent concentrations in drinking water at which no adverse health effects are expected to occur. Additional information on the potential health impacts of PFAS can be found on our Per- and Polyfluoroalkyl Substances (PFAS) webpage.
On April 11, 2025, the Illinois Pollution Control Board published adopted amendments to Part 620 in the Illinois Register. The adoption of final amendments to Part 620 included establishing standards under Section 620.410 for PFAS analytes including Perfluorobutanesulfonic Acid (PFBS), Perfluorohexanesulfonic Acid (PFHxS), Perfluorononanoic Acid (PFNA), Perfluorooctanesulfonic Acid (PFOS), and Perfluorooctanoic Acid (PFOA). Therefore, the standards in Section 620.410 for these PFAS analytes replace the previously issued health advisories. Health advisories for Perfluorohexanoic Acid (PFHxA), issued on January 28, 2021, and updated on April 26, 2023, and for Perfluorobutanoic Acid (PFBA), issued on September 16, 2024, remain in effect.
The final amendments to Part 620 include updates to exposure factors used for calculating health-based guidance levels. The updated exposure factors account for adverse effects from exposure for children. Previously, the exposure factors in Part 620 calculated health-based guidance levels based on adult exposure.
On April 11, 2025, Illinois EPA issued the Health Advisory updates for PFHxA and PFBA to reflect the exposure factor updates. The updated health advisory for PFHxA is 0.0019 milligrams per liter (mg/L), or 1,900 nanograms per liter (ng/L) or parts per trillion (ppt). The updated health advisory for PFBA is 0.0038 milligrams per liter (mg/L), or 3,800 nanograms per liter (ng/L) or parts per trillion (ppt).
Below is a summary of PFAS analytes with Statewide Health Advisories. The levels are presented in nanograms per liter (ng/L), equal to parts per trillion (ppt). For reference:
Current Statewide Health Advisories for PFAS
Illinois EPA calculates HBGLs for all PFAS analytes for which sufficient toxicity information is available and accepted by U.S. EPA. The groundwater quality standards for PFBS, PFHxS, HFPO-DA, PFNA, PFOS and PFOA published in Part 620 replace previously issued HBGLs. The table below provides a summary of current PFAS HBGLs:
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| CAS Registry Number | PFAS Analyte | Acronym | Health-Based Guidance Level (ng/L or ppt) | Health Advisory Issued (Yes/No) |
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* The HBGL is less than the minimum reporting level (MRL) of 2 ng/L.