DEQ presents PFAS sampling, EPA rule and timelines as state prepares to adopt drinking-water limits

Tyler Fortuneotti, chief of the Drinking Water Bureau at the Idaho Department of Environmental Quality, told the Senate Health and Welfare Committee that nationwide action and new federal limits are reshaping how Idaho tests and prepares for per- and polyfluoroalkyl substances in public drinking water.

Fortuneotti described the U.S. Environmental Protection Agencyrule finalized in April 2024 that sets maximum contaminant levels (MCLs) for six PFAS chemicals and requires initial monitoring by April 2027, reporting in consumer confidence reports beginning in April 2027, public notification beginning in 2029, and compliance with the MCLs by April 2029. "Water systems are required to complete initial monitoring ... and that initial monitoring will then dictate the frequency of their routine monitoring going forward," Fortuneotti said.

Why it matters: the MCLs are set at parts-per-trillion concentrations, which can trigger costly treatment, source changes or system interconnections for public water systems. Fortuneotti said Idaho has detected PFAS at both the source and system level during several sampling efforts and is seeking the committee's support to incorporate the EPA drinking-water rule by reference into Idaho's rules for public drinking water systems; the committee deferred a vote until next week.

What DEQ presented and what the state has found - The Department of Defense sampled installations in Idaho and found PFAS at Mountain Home Air Force Base in multiple public-water sources; the base installed treatment on Well No. 4 in 2018. That treatment installation cost was reported as $1,360,000 with an ongoing operation and maintenance cost reported as $100,000; the well produced about 1,300 gallons per minute and was taken offline in 2020. - Under an EPA unregulated contaminant monitoring effort (UCMR5, described by Fortuneotti as the fifth iteration), 61 Idaho public water systems were selected; 41 had reported results at the time of the presentation and seven systems had detections under that federal effort. Fortuneotti said one of those seven systems had results that would exceed the EPA MCL and that system is in the Boise region. - DEQhas run a voluntary sampling project since April 2021, funded with EPA emerging-contaminant-specific SRF capital. DEQ reported sampling 381 of the state's 3,219 active public-water sources (about 12%); 66 of those sources had detections (about 17% at the source level). At the public-water-system level, DEQ sampled 203 of Idaho's roughly 2,016 regulated public water systems (about 10%), and 58 systems have shown PFAS detections (about 28% of sampled systems). The highest detection reported in the DEQ samples was 42.2 parts per trillion.

Options and costs discussed Fortuneotti outlined the range of options a system may consider if monitoring indicates MCL exceedances: additional sampling to calculate the running annual average used for compliance, consulting with engineers or in-house teams, installing treatment (as at Mountain Home AFB), developing new sources and abandoning contaminated sources, or interconnecting with another system. He said costs vary widely depending on concentration, system size and the number of users sharing the cost.

On soil contamination and remediation costs, Fortuneotti said he could not provide detailed cost estimates and would coordinate with DEQ's Waste Management Remediation Division for answers. "I can't speak much to that and the costs associated with it. I would have to get information from our waste management remediation division," he said.

Rural systems and public notice When asked how rural Idaho systems would be affected, Fortuneotti said the same compliance options apply but noted that interconnection may be logistically harder in remote areas. On public notification, he said the federal rule requires public water systems to deliver public notifications beginning in 2029 if they exceed the MCL, and in the interim DEQ provides templates and encourages systems to communicate results to their users. He added that DEQ notifies the local health district and its regional offices when it finds detections.

Funding available and next steps Fortuneotti described state revolving fund (SRF) resources for treatment projects, estimating roughly $7,600,000 per year available through SRF capitalization plus an additional $1,000,000 for wastewater. Systems seeking SRF funding must submit a letter of interest and document the PFAS issue; Fortuneotti said the current LOI cycle had just closed and the next begins in October.

The committee did not take a vote on the rule at this meeting; a committee member said, "We don't have the pending rule before us today, so we'll vote on that next week." Fortuneotti had asked the committee to support adoption of the department's docket to incorporate EPA's PFAS drinking-water rule by reference.