MassDEP outlines approach to PFAS in private wells and public water at advisory meeting

At a MassDEP Bureau of Waste Site Cleanup (BWSC) Wayside Cleanup Advisory Committee meeting, John Ziegler, the statewide PFAS coordinator in the department's Policy and Program Development division, described how MassDEP handles PFAS detections in private wells and public water systems and what triggers departmental action.

Ziegler said the department treats private wells differently than public systems: "MassDEP does not regulate private wells; they are regulated by the local board of health," but added that when PFAS results meet the state's reportable levels they inform MassDEP's source-discovery work. He noted that the state drinking-water level for the six PFAS compounds (PFAS-6) is 20 parts per trillion (ppt) and that the MCP imminent-hazard threshold is 90 ppt.

Why it matters: Private well owners and municipal water suppliers have different reporting and regulatory paths, but any result at or above 20 ppt helps MassDEP identify possible sources. The department’s immediate goal at impacted private wells is hazard mitigation; its longer-term objective is to find the contaminant source so that cleanup or controls can be pursued.

Most important facts first: Ziegler said MassDEP typically responds to private-well notifications by evaluating imminent hazard and, where appropriate, providing point-of-entry treatment such as lead/lag granular activated-carbon (GAC) POET systems and, in some cases, bottled water while a longer-term solution is arranged. For public water systems the Drinking Water Program regulates sampling and treatment; MassDEP’s BWSC coordinates on source investigation if a system’s raw or finished water exceeds 20 ppt.

Supporting details: Ziegler summarized recent data and programs: a UMass sampling project produced a dataset of more than 1,600 private-well results that were reported to MassDEP; to date MassDEP has installed about 60 POET systems and provided bottled water at 32 locations where imminent hazards exist. He said roughly 6 percent of private wells in the referenced UMass study exceeded 20 ppt and about 1 percent exceeded the 90 ppt imminent-hazard threshold. For public systems, roughly 1,400 public water suppliers are required to test for PFAS and, as of the meeting, about 177 systems had detected PFAS above the Massachusetts MCL.

Method and next steps: Ziegler described the department’s source-discovery workflow: desktop review of nearby potential PFAS sources (AFFF use, fire-training areas, manufacturing sites), requests for information to likely source properties, and targeted sampling where indicated. Where a responsible party is identified, BWSC may issue Notices of Responsibility and pursue cleanup under the MCP; where no responsible party is available or willing and an imminent hazard exists, the department may step in to mitigate exposure.

What MassDEP asked of stakeholders: Ziegler requested that local boards of health and homeowners notify MassDEP when testing identifies PFAS above 20 ppt, so the department can include those results in source-discovery efforts. He also pointed listeners to a Drinking Water Program story map showing public systems with PFAS detections and treatment status.

Context and limits: Ziegler made clear that private wells are primarily local-board-of-health jurisdiction, and that MassDEP’s immediate role is hazard mitigation and source identification when MCP reporting thresholds are met. He also said regional BWSC offices carry out the field work and that MassDEP is coordinating with the Drinking Water Program on public-system responses.

Ending: Ziegler closed by pointing stakeholders to MassDEP contacts and the PFAS Q&A under development and invited written questions and site notifications to support the department's ongoing source-discovery work.