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), ion exchange and membrane processes, and said the study focused on technologies already in common use.

County Public Works Director Austin McFarland told the committee the department has already been proactive in sampling and will expand monitoring. McFarland said the department is preparing for updated permit language that will likely add monitoring and reporting requirements for wastewater and biosolids.

Key details from the presentation and discussion

- Regulations and schedule: Donahue said the U.S. EPA finalized a drinking-water rule in April 2024 and, as of August 2025, the agency set MCLs (maximum contaminant levels) for six PFAS compounds. Monitoring by public-water systems will be required (quarterly or two samples within a 12‑month period depending on system size and water source) by April 2027, and utilities must comply with the MCLs by April 2029, the consultant said.

- Current county results: Donahue reported that county drinking-water samples collected to date are below the EPA MCLs cited in the presentation; many results were "below the reporting limit" (the lab’s minimum reporting concentration), and thus at least half or lower than the stated MCLs. For wastewater effluent, Donahue compared Lake County results with Wisconsin’s enforceable standards and found Lake County effluent levels were below those Wisconsin thresholds. For biosolids, some summed PFAS/PFOA concentrations would trigger additional sampling and source‑investigation under Wisconsin’s tiered approach, the consultant said; Wisconsin, unlike Illinois, already has enforceable limits the consultants used as a comparison point.

- Treatment and costs: Donahue said membrane systems (nanofiltration/reverse osmosis) are effective but expensive and energy‑intensive and therefore were not carried forward for county cost analyses. The study focused on activated carbon and ion exchange. The presentation included 20‑year present‑worth cost estimates for small, medium and large water-supply sites; the consultant reported approximate 20‑year totals of $5,000,000 for small systems, $7,000,000 for medium systems and an estimated figure reported in the study for large systems. (The consultant emphasized these are planning‑level estimates.)

- Wastewater and biosolids: There are no federal effluent or biosolids PFAS limits at present, the consultants said, but permit language is changing to require monitoring, reporting and consideration of reduction initiatives. Donahue noted technologies for destroying PFAS in biosolids (for example, incineration or pyrolysis) are emerging; pyrolysis systems are new and large, and the consultant provided a planning estimate for a county‑scale pyrolysis treatment option across all plants.

What officials recommended and will do next

- Continue and expand monitoring: County staff have been collecting samples and will add monitoring spots in the collection system and in the wastewater plants to identify potential source areas.

- Pursue source reduction: Consultants and staff emphasized that preventing PFAS from entering the sanitary system and drinking-water supply (through industrial pretreatment, product substitution and public outreach) is a cost‑effective strategy compared with large‑scale treatment or disposal technologies.

- Strengthen pretreatment and outreach: Director McFarland said the county is drafting a pretreatment ordinance and will begin sampling industrial dischargers as part of that program. Committee members urged a robust public education campaign to help residents and businesses identify PFAS‑containing products and safe disposal options.

- Stay current with regulation and funding: Donahue said Illinois permit language and federal guidance may change in the coming year; county staff said they will watch legislative and federal funding opportunities that could help pay for monitoring or mitigation.

Committee reaction and next steps

Committee members emphasized public outreach, urged the county to accelerate pretreatment enforcement capacity, and asked that staff pursue state and federal funding and legislative options. Director McFarland said the county will continue its proactive monitoring program, finalize the pretreatment ordinance and return with updates.

Ending

The consultants closed by saying the county’s existing sampling shows the systems are meeting current drinking‑water limits but that PFAS will remain an active policy and technical issue; county staff said they would bring follow‑up reports as monitoring continues and regulatory guidance evolves.