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Notification to Community Water System Users
The 2009 Right-to-Know law requires Community Water System (CWS) owners and operators to notify all end users when groundwater contamination poses a threat of exposure above the Class I groundwater quality standards.
On December 7, 2021, the Illinois EPA filed 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 Per- and Polyfluoroalkyl Substances (PFAS), based on the most recent scientific information available:
- perfluorooctanoic acid (PFOA)
- perfluorooctanesulfonic acid (PFOS)
- hexafluoropropylene oxide dimer acid, also known as GenX (HFPO-DA)
- perfluorohexanesulfonic acid (PFHxS)
- pefluorononanoic acid (PFNA)
- perfluorobutanesulfonic acid (PFBS)
On April 11, 2025, the Board's adopted amendments to Part 620 were published in the Illinois Register, triggering Right-to-Know notifications to the owners and operators of 21 Community Water Systems (CWSs) where there has been a detection of one or more PFAS in the most recent water sampling at levels exceeding the newly enacted groundwater quality standards. The Illinois EPA also notified owners and operators of 26 connected CWSs that obtain water from CWSs that had one or more PFAS exceedances.
Below is the press release announcing the Right-to-Know notifications, a complete list of the affected systems, the new groundwater quality standards, and the most recent detected concentration, and the Public Health Notice.
The notification documents listed below were issued by the Illinois Environmental Protection Agency (Illinois EPA):
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| Community Water System (CWS) | County | Press Release Issued | Notice to Primary CWS | Notice to Connected CWS | Date Posted |
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