PFAS - An Emerging Groundwater Contaminant

Per- and polyfluoroalkyl substances – known as PFAS – are an emerging contaminant being closely monitored by community water supply officials.

  

 

In April 2025, the Village of Rockton sent Illinois EPA mandated notifications to all our water customers stating we were exceeding one of six newly established limits for Per- and Polyfluoroalkyl Substances (PFAS) at Well #5. To provide our community with the best possible water quality, in January 2026 we began pilot testing 3 advanced filtering systems. This pilot program will run for up to a full year and is simultaneously evaluating three types of media known to be effective in treating PFAS. Using systematic testing and sampling processes, we will determine the best treatment media and begin the process of adding a full-scale, permanent deployment. Results will be posted as they become available.  As of July 2026 all three are proving effective at filtering out PFAS.

 

In a world where regulations and science are constantly evolving and changing, the Village of Rockton's foremost concern is to provide for the health, safety, and happiness of our residents. To that end, we wanted to share this exciting news with you all. 

 

As of April 2025, new groundwater quality standards introduced by the Illinois Pollution Control Board (IPCB) in conjunction with the Illinois Environmental Protection Agency (IEPA) detailing maximum contaminant levels for six PFAS analytes are:

 

  • Perfluorooctanoic acid (PFOA): 4 parts per trillion (ppt)
  • Perfluorooctanesulfonic acid (PFOS): 4 parts per trillion (ppt)
  • Perfluorononanoic acid (PFNA): 10 parts per trillion (ppt)
  • Perfluorohexanesulfonic acid (PFHxS): 10 parts per trillion (ppt)
  • Perfluorobutanesulfonic acid (PFBS): 2000 parts per trillion (ppt)
  • Hexafluoropropylene oxide dimer acid (HFPO-DA or GenX): 10 parts per trillion (ppt)

 

Current and past Village of Rockton sampling and testing data can be viewed in our Consumer Confidence Reports, by visiting our Annual Water Quality Reporting page.

 

Please visit the links and attached documents below for more information

 

35 Illinois Administrative Code (IAC)  (Part 620: Groundwater Quality Standards)

Illinois EPA PFAS Webpage (General information and updated regulations)

IEPA Public Health Notice - April 2025
PFAS Right-to-Know Notice - 2025
Water Customer PFAS Notice - 2021
Water Customer PFAS Fact Sheet - 2021