Lake County study finds PFAS levels below current drinking-water limits; officials urge source reduction and more monitoring

At a Sept. 3 meeting, Lake County Public Works presented results of a yearlong review of per‑ and polyfluoroalkyl substances, or PFAS, describing current monitoring results, likely future regulatory timelines and options if treatment becomes necessary.

The county’s consultant, Donahue & Associates, told the committee that drinking-water samples collected so far from county systems have been below the federal maximum contaminant levels finalized by the U.S. Environmental Protection Agency and adopted in August 2025 for six PFAS compounds, and that wastewater effluent and biosolids samples were low compared with guidance used in Wisconsin.

Why it matters: PFAS are widely used, persistent chemicals linked to health concerns; new federal drinking-water limits and monitoring requirements mean utilities must sample, report results and be prepared to act. County staff and the consultant said source reduction — stopping PFAS from entering systems — is the most practical first line of defense. They also outlined treatment options, likely costs, and next steps in monitoring and outreach.

Consultant Nathan Cassidy, project manager at Donahue & Associates, summarized analytical findings and regulatory context, saying, "PFAS are...very, very tiny particles" that "don't break down in nature," and that treatment technologies exist but can be costly. Han Ting Wang, a Donahue water and wastewater process engineer, described treatment options the county evaluated, including adsorption (activated carbon),…