DEQ outlines PFAS presence, monitoring timeline for Idaho drinking water; formal rule vote deferred

The Idaho Senate Health and Welfare Committee heard a presentation on per- and polyfluoroalkyl substances (PFAS) in drinking water from Tyler Fortunati, chief of the Drinking Water Bureau at the Idaho Department of Environmental Quality (DEQ). Fortunati described federal requirements, statewide sampling results, treatment costs at an affected Air Force base and funding options for public water systems. The committee did not vote on the related rule at this meeting; the chair said the vote would take place at a later date.

Fortunati told the committee that EPA finalized a drinking-water rule in April 2024 that sets maximum contaminant levels (MCLs) for six PFAS analytes at parts per trillion. Under that federal rule, public water systems must complete initial monitoring by April 2027, which will determine routine monitoring frequency beginning May 2027; consumer confidence report reporting begins in April 2027; public notification is required beginning in 2029 if a system exceeds an MCL; and compliance with the MCL is required by April 2029.

Why it matters: PFAS are persistent, can transport through air and water, bioaccumulate and are linked in some studies to human health effects, including an increased risk of certain cancers. The federal MCLs are extremely low (parts-per-trillion levels), which will require monitoring, possible treatment or other mitigation by public water systems.

Key statewide findings presented by DEQ: of 3,219 active public-water sources in Idaho (wells, intakes, springs), DEQ sampled 381 sources (~12%). DEQ reported 66 detections among those sources (~17% of sampled sources). On the public-water-system level, Idaho has 2,016 regulated public water systems, of which DEQ sampled 203 systems (~10%); 58 systems reported detections (~28% of sampled systems). Fortunati reported that measured concentrations in Idaho ranged from about 1 part per trillion to a highest detection of 42.2 parts per trillion. Fourteen systems had one or more sources that could potentially exceed EPA’s MCL; 25 sources within those 14 systems were impacted, and 11 of those sources had two or more contaminants above the MCL thresholds.

Fortunati used the Department of Defense sampling at federal installations as an example. The DEQ presentation noted PFAS detections at Mountain Home Air Force Base and at Gowen Field; Mountain Home’s public water system had detections in multiple sources in 2016. The base installed treatment on Well Number 4 in 2018 (the well produces about 1,300 gallons per minute), with an initial installation cost Fortunati reported as $1,360,000 and an ongoing operation and maintenance cost quoted at $100,000; that well was taken offline in 2020.

On mitigation options, Fortunati said systems that average at or above an MCL (the EPA standard is based on a running annual average) would consult with engineers or consultants to identify feasible options. Potential options include installing treatment (as the Air Force did), abandoning a contaminated source and developing a new source, or interconnecting with another public water system where feasible. Fortunati emphasized that the cost and feasibility depend on contaminant concentration, system size and the number of users sharing the cost.

Funding and assistance: DEQ said states may help systems apply to the State Revolving Fund (SRF). The DEQ noted approximately $7,600,000 is available annually in SRF capitalization grants for drinking water assistance plus $1,000,000 for wastewater programs during fiscal years 2023–2027, and that EPA emerging-contaminant-specific funds supported the DEQ’s voluntary sampling project.

Committee questions and DEQ responses: Senator Wintrow said constituents contacted her with support for the rules but with questions about treatment options and soil contamination. Fortunati said DEQ’s drinking-water program can address water-source monitoring and treatment but that soil remediation questions would require input from DEQ’s waste management/remediation division; he offered to provide that follow-up information. On public notification, Fortunati said the federal rule triggers required public notification beginning in 2029; before then DEQ provides templates and encourages voluntary communication and notifies the local public health district when DEQ sampling finds detections.

Next steps: Fortunati asked the committee for support to adopt the pending rule docket (the docket strings cited in the record include variations of the docket identifier). The chair confirmed the rule was not before the committee for a vote that day and said the vote would occur at the next scheduled meeting.

Ending: The presentation provided the committee with statewide sampling results, timelines tied to EPA deadlines, an example of treatment costs at a military installation, and funding pathways available to public water systems. The committee deferred formal action on the rule to a later session, and DEQ committed to follow up with additional details (for example, on soil remediation costs) requested by committee members.

"This presentation is related to docket number 50Eight-one-eight-two401," Tyler Fortunati said during his introduction. "I again ask for the committee's support to adopt rule docket 58,100 and eight-two 401 and I will stand for any questions."