Bottom line
What changes if EPA finalizes the rescission as proposed: the federal standards, monitoring duties and compliance dates for PFHxS, PFNA, HFPO-DA and the Hazard Index mixture disappear from 40 CFR part 141 on the final rule's effective date, while the PFOA and PFOS standards at 4 ppt stay and state PFAS standards continue to bind where they exist. Until then the 2024 rule is in force: the D.C. Circuit twice declined to vacate the four standards at EPA's request, heard argument on the whole rule on September 18, 2026 and has not decided, and the initial monitoring deadline for all six PFAS is April 26, 2027. EPA said it would act in 2026; its agenda target of September 2026 has passed. ComtIQ judges a final rescission likely, a petition for review almost certain, and the outcome of that review close to even. Opposition in the record is broad and mostly individual: 1,477 of 1,555 comments oppose, 193 of them in 15 coordinated campaigns, and three petitions filed as single comments carry about 20,900 listed signature entries between the two that ComtIQ counted (0080, 0170), with a third list uncounted (0083). The organized support is concentrated in water utilities and their associations, the chemical industry and ten local governments.
8 forecasts to score when the final rule publishes
| # | Forecast | Likelihood | Confidence | Confirmed if |
|---|---|---|---|---|
| 1 | EPA publishes a final rescission rule by June 30, 2027 | Likely | Low | Federal Register, RIN 2040-AG53 |
| 2 | If a final rule publishes, it rescinds the determinations and the standards for all four PFAS as proposed | Likely | Moderate | Final rule text, 40 CFR 141.61 |
| 3 | The final rule keeps a monitoring or occurrence-data requirement for the four PFAS | Unlikely | Low | Final rule text, 40 CFR 141.902 to 141.905 |
| 4 | EPA adopts the procedural cure, keeping the determinations and re-proposing the standards, instead of rescinding | Very unlikely | Moderate | Final rule, or a remand order |
| 5 | The D.C. Circuit decides American Water Works Association v. EPA before the final rescission publishes | Roughly even chance | Low | D.C. Circuit opinion date against the Federal Register date |
| 6 | A petition for review of the final rescission is filed within the 45-day window of SDWA section 1448 | Almost certain | High | Petition docketed in the D.C. Circuit |
| 7 | If a final rescission publishes and is challenged, the court upholds it on the merits (a remand without vacatur counts as not upheld) | Roughly even chance | Low | Court of appeals judgment |
| 8 | EPA proposes a new standard for any of the four PFAS by December 31, 2028 | Unlikely | Low | Federal Register |
What the record shows
- 1The remedy is the open question, and the record names an alternative EPA did not propose.
- 2Local governments and state agencies lean opposite ways.
- 3The anti-backsliding clause divides the two sides on what counts as a baseline.
- 4Supporters want the rescission and, in several cases, more.
- 1.2%Three petitions carry most of the listed public signatures and count as three comments.
Who should act now
- Public water system
- State primacy agency
- Industrial discharger or pretreatment program
- Chemical manufacturer or PFAS defendant
- Law practice or policy team
- Public health or environmental organization
Dates to watch 2024 rule published April 26, 2024 (89 FR 32532), with initial monitoring due April 26, 2027 and MCL compliance due April 26, 2029; a separate 2026 proposal would let systems seek until 2031 for PFOA and PFOS, and it is a proposal; proposal published May 20, 2026 (91 FR 29413); hearing July 7, 2026; comments closed July 20, 2026; AWWA v. EPA argued September 18, 2026, decision pending; no final rule found as of November 7, 2026. A petition for review of a final rule must be filed within 45 days of its promulgation (SDWA section 1448, 42 U.S.C. 300j-7), and filing does not stay the rule. A final rule takes effect on the date its text sets, whatever the state of the litigation, unless a court orders otherwise. Watch the Federal Register and the Unified Agenda for RIN 2040-AG53 and the D.C. Circuit docket for No. 24-1188.