DEQ briefs Senate committee on PFAS in Idaho drinking water; EPA rule to be adopted by reference

Tyler Fortunati, chief of the Drinking Water Bureau for the Idaho Department of Environmental Quality, told the Senate Health and Welfare Committee that the EPA finalized a rule in April 2024 that sets maximum contaminant levels (MCLs) for six PFAS chemicals and that Idaho plans to adopt that rule by reference into state drinking water rules.

The presentation summarized what PFAS are, the federal compliance timeline, Idaho sampling to date, and funding options for water systems that need treatment. Fortunati said EPA requires initial monitoring by April 2027, routine monitoring frequency set by May 2027, consumer confidence reporting beginning April 2027, public notification if MCLs are exceeded starting in 2029, and compliance with the MCLs by April 2029.

PFAS (per- and polyfluoroalkyl substances) are a large family of man-made chemicals used for water-, grease- and stain-resistant properties in many products and firefighting foams. Fortunati said the compounds break down very slowly, bioaccumulate, transport in air and water, and that scientific understanding of the toxicity of many newer PFAS is still emerging. He listed human-health concerns associated with PFAS exposure, including an increased risk of some cancers for certain compounds.

On monitoring and Idaho results, Fortunati described three sampling efforts: Department of Defense sampling at military installations, EPA’s Unregulated Contaminant Monitoring Rule (UCMR5) selection of public water systems, and a voluntary DEQ sampling project funded with EPA emerging-contaminant funds that began in April 2021. Key numbers Fortunati gave: Idaho has 3,219 active public-water sources; DEQ has sampled 381 (about 12% of sources) and found 66 detections at the source level (~17% of sampled sources). At the public-water-system level, DEQ has sampled 203 of 2,016 regulated systems (about 10%) and 58 systems had detections (~28% of systems sampled). The range of detections in the DEQ sampling ranged from about 1 part per trillion (ppt) to a high of 42.2 ppt. Fortunati said 14 systems (25 sources) may have one or more sources with concentrations that would potentially exceed the EPA MCLs; 11 sources had detections of two or more regulated PFAS above the MCL.

Fortunati cited prior treatment installed at Mountain Home Air Force Base in 2018 on Well No. 4, which produces about 1,300 gallons per minute; the initial installation cost was $1,360,000 with an ongoing operation-and-maintenance cost of about $100,000 at the time. That well was taken offline in 2020. He said EPA selected 61 Idaho public-water systems for UCMR5 monitoring for up to 29 PFAS analytes; 41 of those systems had reported results to EPA at the time of his presentation and seven of the selected systems had detections under UCMR5, with one system in the Boise area having results that would exceed EPA’s MCLs.

On the question of options and costs for systems that exceed MCLs, Fortunati said systems typically will continue sampling to establish a running annual average (the basis for compliance), consult with engineers or consultants, and consider options including installing treatment, abandoning a contaminated source and developing a new one, consolidating by connecting to another system, or other engineering solutions. He said DEQ’s State Revolving Fund (SRF) offers funding and that the SRF has about $7.6 million annually available for drinking-water assistance plus an additional $1 million for wastewater; emerging-contaminant-specific Bipartisan Infrastructure Law funding is available through fiscal 2023–2027 capitalization grants, and DEQ requires a letter of interest and documentation of a PFAS issue for projects seeking SRF assistance. Fortunati said the current LOI cycle had just closed and the next opens in October.

Senator Wintrow pressed about treatment and soil remediation; Fortunati said he could not speak to soil remediation costs without input from DEQ’s waste management remediation division and offered to follow up. On impacts in rural Idaho, Fortunati said the federal rule and Idaho’s proposed incorporation by reference apply to public drinking-water systems statewide, and rural systems face the same array of technical options (treatment, new sources, interconnection), although consolidation may be logistically harder in remote areas and per-user costs may be higher for small systems.

Fortunati asked the committee for support to adopt the EPA rule by reference (docket referenced during the presentation). The committee did not take a vote on the rule that day; the chair said the pending rule would be voted on next week.