The Illinois Environmental Protection Agency (Illinois EPA) will be conducting a statewide investigation into the prevalence and occurrence of Per- and Polyfluoroalkyl Substances (PFAS) in finished water at 1,456 entry points to the distribution system representing 1,749 community water supplies (CWSs) across Illinois. The purpose of this investigation is to support the potential development and promulgation of maximum contaminant level (MCL) standards in Illinois for certain PFAS, and to respond to scientific data throughout the nation regarding the effects of PFAS on public health. Samples will be analyzed using United States Environmental Protection Agency (U.S. EPA) Method 537.1. Illinois EPA, in conjunction with the U.S. EPA, has developed a Quality Assurance Project Plan (QAPP) for this investigation network. The QAPP also contains a Standard Operating Procedure (SOP) for sample collection. For further detail see the Process to Establish Maximum Contiminant Levels for PFAS in Illinois.

Learn more about PFAS in Illinois:

• PFAS Investigation Network Interactive Dashboard and Map
• Groundwater Standards Development
• Process to Establish Maximum Contaminant Levels for PFAS in Illinois