NJDEP Adopts Interim Specific Groundwater Standards for PFAS

On June 15, the New Jersey Department of Environmental Protection (NJDEP) published a notice of rule adoption formally establishing new regulatory standards applicable to hexafluoropropylene oxide dimer acid and its ammonium salt (collectively, GenX), perfluorononanoic acid (PFNA), perfluorooctanoic acid (PFOA), and perfluorooctane sulfonic acid (PFOS).¹ This latest regulatory action sees the NJDEP continuing to broaden New Jersey’s regulation of per- and polyfluoroalkyl substances (PFAS), a category the agency has identified as chemicals of emerging concern. 

New Regulatory Standards

New Jersey has long been a national leader in PFAS regulation, becoming the first state to set drinking water standards for PFAS when it adopted a maximum contaminant level for PFNA in 2018 and set limits for PFOA and PFOS in 2020.² With the adoption of this new rule, New Jersey is now one of the first states to establish regulatory standards that are directly applicable to a widely characterized “replacement” PFAS: GenX.

NJDEP amended its Ground Water Quality Standards (GWQS) to formally establish for GenX (i) an interim specific groundwater quality criterion of 0.02 parts per billion (ppb), (ii) a practical quantitation level of 0.0075 ppb, and (iii) a specific groundwater quality standard of 0.02 ppb.³

NJDEP also established remediation standards for soil and soil leachate for PFNA, PFOA, PFOS, GenX, and methanol as formally promulgated standards.⁴ Interim soil and soil leachate standards for PFNA, PFOA, PFOS, and GenX previously had been published in October 2022.⁵

As part of the same rulemaking, the agency adopted amendments to the Technical Requirements for Site Remediation (Tech Regs) with respect to quality assurance for sampling and laboratory analysis to add GenX, PFNA, PFOS, PFOA, and 2,3,7,8-tetrachlorodibenzo-p-dioxin. Accordingly, each of these chemicals must now be analyzed in all media when hazardous substances in an area of concern are unknown or not well documented. NJDEP “is including these chemicals because they have been widely used or are prevalent in the State [of New Jersey].”⁶

Forward-Looking Implications

Responsible parties currently investigating and remediating PFAS in New Jersey must ensure their environmental work complies with the new standards, where applicable. Further, for sites where PFAS was historically used in manufacturing, responsible parties may be compelled to investigate whether those operations ever used GenX, which may necessitate an environmental investigation for potential GenX impacts. For remediation projects that are meaningfully progressed, complying with these new standards may present challenges to satisfying mandatory remediation time frames and may generally result in lengthier and more costly site investigation, remediation, and restoration.

Additionally, New Jersey’s new stringent regulatory standards for GenX signal that the state is continuing to expand its efforts to regulate PFAS generally – not just the “legacy” PFOA, PFOS, and PFNA that have garnered the most widespread attention – even while the United States Environmental Protection Agency (USEPA) under the Trump Administration has rolled back some PFAS regulatory efforts and may be unlikely to implement new federal regulations in the near future.⁷ This rulemaking is the latest in an ongoing trend among states with a more progressive environmental focus toward regulating a broader universe of PFAS chemicals.

Responsible parties that currently or historically used or manufactured PFAS should closely monitor this and other forthcoming rulemakings on a state-by-state basis to ensure compliance with any applicable requirements. They should also consider proactive preparations for anticipated future regulations in the states in which they operate.

For more information on PFAS and GenX, please contact the authors of this client alert.

¹ See generally Rule Adoption, available at https://dep.nj.gov/wp-content/uploads/rules/adoptions/adopt-20260615b.pdf.
² NJDEP, NJDEP Formally Adopts Site Remediation Standards for PFAS Compounds Including PFNA, PFOA, PFOS and GenX (Jun. 15, 2026), available at https://dep.nj.gov/newsrel/26_0032/.
³ Rule Adoption, at 2.
⁴ Rule Adoption, at 2.
5 NJDEP, Public Notice, Notice of Establishment of Interim Remediation Standards, available at https://dep.nj.gov/wp-content/uploads/rules/adminchg/adminchg-20221017a.pdf.
⁶ Rule Adoption, at 3.
⁷ On May 20, 2026, USEPA published a proposed rule rescinding its regulatory determinations to regulate four PFAS, including GenX. Rescission of Regulatory Determinations and Removal of Related Provisions for Four PFAS Substances, available at https://www.federalregister.gov/documents/2026/05/20/2026-10085/rescission-of-regulatory-determinations-and-removal-of-related-provisions-for-four-pfas-substances. Comments are due July 20, 2026. Id.