DEQ presents statewide PFAS sampling results, urges adoption of EPA drinking-water rule

Tyler Fortunati, chief of the Drinking Water Bureau at the Idaho Department of Environmental Quality, told the Senate Health and Welfare Committee that per- and polyfluoroalkyl substances (PFAS) are “ubiquitous” and transport readily through air, rain and groundwater.

Fortunati said the presentation — related to a pending docket to update Idaho’s public drinking water rules by incorporating U.S. Environmental Protection Agency requirements — summarized what DEQ and federal testing have found in Idaho, the federal compliance timetable and funding options for water systems that must respond.

The DEQ official said EPA finalized a national drinking-water rule in April 2024 that sets maximum contaminant levels (MCLs) for six PFAS analytes and requires initial monitoring by April 2027, routine monitoring beginning in May 2027, public reporting in consumer confidence reports starting April 2027 and public notification if a system exceeds an MCL beginning in 2029. Fortunati asked the committee to support adoption of the EPA rule by reference into Idaho’s regulations; the committee deferred any vote and will consider the rule at a later meeting.

Why it matters: PFAS are persistent, slow to break down and associated in federal analyses with a range of human-health outcomes, including elevated cancer risk for some compounds. The EPA rule will require many public water systems to begin monitoring and potentially to install treatment, develop alternate sources, or interconnect with other systems to comply.

DEQ sampling and federal monitoring DEQ described three lines of data that inform the state’s view of PFAS in drinking water: (1) Department of Defense testing at military installations; (2) EPA’s Unregulated Contaminant Monitoring Rule (UCMR) cycle; and (3) a voluntary, DEQ-run sampling program funded through EPA emerging-contaminant grants.

Fortunati said the Defense Department detected PFAS at Mountain Home Air Force Base and at Gowen Field; Mountain Home’s public-water system had detections in multiple source wells in 2016. DEQ noted that Mountain Home installed treatment on Well No. 4 in 2018; Fortunati said that well produced about 1,300 gallons per minute, had an initial treatment installation cost of $1,360,000 and an early reported operation-and-maintenance cost of about $100,000. That source was taken offline in 2020.

EPA selected 61 Idaho public water systems under the current UCMR cycle to monitor for 29 PFAS analytes; to date 41 of those systems have reported results and DEQ said seven systems have had detections under that federal monitoring. DEQ’s voluntary sampling program, which began in April 2021, has tested 381 of 3,219 active public-water sources in Idaho (about 12% of sources). From those 381 samples DEQ reported 66 detections (about 17% of sampled sources). At the public-water-system level, DEQ reported it has sampled 203 of roughly 2,016 regulated systems and detected PFAS in 58 systems (about 28% of sampled systems).

Concentrations detected and systems of concern DEQ said the range of detections in their sampling runs from around 1 part per trillion (ppt) to a highest reported detection of 42.2 ppt. Fortunati said 14 systems have one or more sources that could potentially exceed the EPA MCLs; 25 sources across those systems were impacted, and 11 sources had detections of two or more contaminants that would be above the MCLs. DEQ representatives displayed a statewide map showing sampled sources, non-detects and detections; the map did not indicate which detections exceeded MCLs.

Compliance options and funding Fortunati described the practical options a public-water system may pursue if monitoring indicates an MCL exceedance: additional sampling to establish a running annual average (the basis for EPA compliance determinations), engineering study and consultation, source treatment (as Mountain Home pursued), developing new sources, abandoning a contaminated source, or interconnection with another system. He said system-specific decisions generally are made with consultants or engineers working with the local water system and noted costs vary with concentration, required mitigation and system size.

DEQ said it administers a State Revolving Fund (SRF) and anticipates approximately $7.6 million per year (FY2023–FY2027 capitalization grants) available to assist drinking-water systems, with an additional $1 million for wastewater. Systems must submit a letter of interest and document a PFAS issue to get on the potential funding list; DEQ said the next LOI cycle opens in October.

Questions from committee members Senator Wintrow said constituents view the rule as a “first step” and asked about remediation for soil contamination and treatment costs for water systems. Fortunati said DEQ’s Waste Management Remediation Division handles soil remediation and he would provide additional information to senators if requested. On treatment for water systems, Fortunati reiterated the range of mitigation options and the need to average multiple samples to determine compliance under EPA’s running annual average method.

When asked about rural systems, Fortunati said the EPA rule and DEQ’s rulemaking would apply to the same public-water systems whether urban or rural, but options such as consolidation may be logistically harder in remote areas. On public notification, Fortunati noted the EPA rule requires formal public notification beginning in 2029; prior to that date DEQ offers template communications and notifies the affected public water system and the local public health district when DEQ sampling identifies detections.

Committee action The committee did not vote on the PFAS rule at the hearing. Committee leadership said the pending rule would be taken up at the committee’s next scheduled meeting.

Ending note: DEQ asked the committee to adopt by reference the EPA’s April 2024 PFAS drinking-water MCL rule into Idaho’s public drinking water rules; the committee deferred a vote to a later date.