Updates To PFAS Effluent Limitation Guidelines Under The Clean Water Act

According to the Unified Regulatory Agenda, the U.S. Environmental Protection Agency ("EPA" or "the Agency") plans to issue a notice of proposed rulemaking ("NPRM") under the Clean Water Act ("CWA") to update effluent limitation guidelines ("ELGs") for per- and polyfluoroalkyl substances ("PFAS") manufacturers. The Agency planned to publish the NPRM in January 2026, but as of the date of this blog post, EPA has not submitted the NPRM to the Office of Management and Budget for review. As such, the Agency may be delaying publishing the NPRM—perhaps signaling a distinction between the Biden and Trump Administrations' approaches to PFAS regulation.

The Organic Chemicals, Plastics, and Synthetic Fibers ("OCPSF") regulation, promulgated under the CWA, applies to wastewater discharges from more than 1,000 chemical facilities producing over 25,000 end products. A small subset of facilities that manufacture or formulate PFAS—known colloquially as "forever chemicals"—are currently regulated under the OCPSF regulation. But the Regulation does not establish effluent limitations or pretreatment standards for any PFAS compounds. Under the Biden Administration, EPA issued an advanced notice of proposed rulemaking ("ANPRM") indicating that this proposed rule may establish new or revised ELGs, pretreatment standards, and new source performance standards applicable to the OCPSF category to address discharges from PFAS manufacturers.

EPA has not updated the OCPSF regulation since 1993 but issued the ANPRM in March 2021 to initiate data collection and analysis to support new rulemaking—one example of the Biden Administration's focus on PFAS regulation. The ANPRM identified both PFAS manufacturers and PFAS formulators as potential targets for regulation. While PFAS manufacturers are facilities that produce PFAS compounds or precursors, PFAS formulators are facilities that are the primary customers of PFAS manufacturers and that use raw PFAS feedstock to produce (1) commercial or consumer goods or (2) intermediary products for use in the manufacture of commercial goods.

In the ANPRM, EPA stated that it had identified PFAS manufacturers and formulators for potential regulation by conducting the PFAS Multi-Industry Study. As part of the Study, EPA identified PFAS manufacturers and formulators, obtained their PFAS data, and evaluated whether their permits contained effluent limitations or monitoring requirements for PFAS compounds. Plus, EPA met with stakeholders including the FluoroCouncil of the American Chemistry Council and representatives of PFAS manufacturers to collect, in part, supplementary effluent data, information on PFAS compound usage and discharge, and treatment technologies.

Likewise, in the ANPRM, EPA requested additional information on PFAS manufacturers and formulators to inform its planned January 2026 NPRM. EPA requested, in part, information on manufacturing processes, PFAS compound usage, wastewater streams, wastewater treatment activities, analytical methodologies used to monitor wastewater, and studies concerning environmental or human health impacts of PFAS discharges. EPA received nearly 30,000 comments, suggesting potentially complex and contentious rulemaking.

Importantly, the planned NPRM and data collection and analysis referenced in the ANPRM occurred under the Biden Administration, and it is unclear how the Trump Administration will proceed. This potential rulemaking may shed light on the Trump Administration's broader approach to PFAS regulation. Thus far, EPA's approach to PFAS regulation under the Trump Administration has been less aggressive than the Biden Administration's approach, although not as deregulatory as anticipated. For example, EPA published a proposed rule to incorporate exemptions and modifications to the reporting requirements for manufacturers and importers of PFAS under Section 8(a)(7) of the Toxic Substances Control Act. But the Agency is actively defending EPA's designation of certain PFAS as hazardous substances under CERCLA and plans to retain key portions of its rule setting maximum contaminant levels under the SDWA. Thus, while EPA Administrator Lee Zeldin referenced his intent to develop ELGs for PFAS manufacturers in an April 2025 press release, it is unclear whether EPA will propose the ELGs and what they will entail.

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