PFAS Update: DNR Proposes 20 ppt Groundwater Standard for PFOA, PFOS

On July 14, the Department of Natural Resources (DNR) held a public stakeholder meeting on a rulemaking to establish groundwater standards for several PFAS compounds. Notably, DNR staff announced that the proposed rule will only seek to regulate two compounds, PFOA and PFOS. The scope statement for the rule included the possibility of regulating PFBS and “GenX” chemicals (HFPO-DA and its ammonium salt). Groundwater quality standards are contained in Chapter NR 140 of the Wisconsin Administrative Code.

DNR is proposing a 20 parts per trillion (ppt) combined standard for PFOA and PFOS. This standard is drawn from the “Cycle 10” groundwater recommendations from the Department of Health Services. DNR currently uses the 20 ppt standard for “public notification” purposes related to these compounds. The current enforceable drinking water standard, adopted last year, is 70 ppt combined for PFOA and PFOS.

DNR’s anticipated timeline for the rulemaking is as follows:

  • Prepare the proposed rule and draft economic impact analysis (EIA) by winter 2023; solicit information for the final EIA.
  • Hold public hearings on the proposed rule in summer 2024.
  • Present the rule to the Natural Resources Board for adoption by the end of 2024.
  • Complete the gubernatorial and legislative review processes for the rule to become effective by summer 2025.

Comments and questions during the call were mostly from environmental and local activists who raised concerns and expressed disappointment with the limited scope and lengthy timeline of the rulemaking. In response to questions, DNR staff said that the decision not to include PFBS and HFPO-DA in the rulemaking “was an upper management decision” and that “Cycle 11 compounds [including PFBS, HFPO-DA, and several other PFAS] are still under consideration for future action.”