99.9% Removal in New York While the Federal Landfill Leachate PFAS Rule Waits Until March 2027

New York's Department of Environmental Conservation filed the express terms for its landfill leachate rule on July 1, 2026, and closed the comment window on September 9. Six weeks into that window, on August 11, EPA's Office of Water signed a three-page memo withdrawing the 2022 guidance that told state permit writers how to put PFAS conditions into a discharge permit. Two regulators, ten weeks, opposite directions. If you run a landfill with a leachate collection system, landfill leachate PFAS regulation now turns on which desk your file sits on, and the desk that matters belongs to a state.

Five claims have come up in nearly every conversation I've had about this since July. The filings dispose of all five.

Is 99.9 percent removal a water-quality standard?

No, and DEC says so itself. Past the cost tables in the Regulatory Impact Statement sits the sentence that should have reframed every comment letter filed on this rule:

The quantitative treatment requirement is not based on achieving a human health or environmental risk assessment-based outcome. Instead, it is intended to function as an achievable and measurable criterion that facilities and the department can use to determine compliance with the regulation.

Read that twice. The 99.9 percent figure in new Subpart 363-12 doesn't derive from a drinking-water standard, an ambient criterion, or a toxicity endpoint for anything in Tables 3A and 3B. It's a bookkeeping test. DEC's theory is that a landfill is where the chemistry of consumer products ends up concentrated, and that it should stay concentrated there, so the stream leaving the treatment building carries a thousandth of what entered it.

That distinction decides how you fight it. But a percentage-removal criterion can't be argued down with a risk assessment, because the agency has already conceded it isn't a risk number. The objections with traction are analytical, and Sanborn Head raised the sharpest one in its client alert: push a contaminant down three orders of magnitude and you land under the quantitation limit for the method. Nobody can then prove compliance, and the department can't prove a violation either. Most operating plants make that worse, because a conventional biological train with filtration was sized to knock down BOD and ammonia, and the leachate those plants were built for is not what arrives at the equalization tank now.

Did EPA's withdrawal take PFAS out of your permit?

The August memo, signed by Office of Water Assistant Administrator Jessica Kramer, pulled the December 2022 guidance along with four other documents. EPA's reasoning was that the previous administration had put "the cart before the horse" by pushing PFAS through NPDES permitting before setting discharge standards for specific compounds and specific sectors. That's defensible as administrative sequencing. As a description of what lands in your permit, it changed almost nothing.

The 2022 memo never bound anyone. It was model permit language, a template a state writer could pick up if they wanted one, and most didn't need it. The great majority of NPDES programs are delegated, and a delegated writer's authority to set a case-by-case limit comes from the Clean Water Act and that state's own water-quality standards, not from a guidance document EPA can rescind on a Tuesday. New York runs its own SPDES program. And its permit writers kept every tool they had on August 10.

Where the withdrawal does bite is the short list of jurisdictions EPA still permits directly. Massachusetts, New Hampshire, New Mexico, the District of Columbia and the territories have no delegated authority, and their permits now come from an agency that has said plainly it won't write PFAS conditions before the rule exists. Discharge in one of those five and you got a reprieve. Everyone else got a press release.

Can you wait for the federal effluent guidelines?

Not on a schedule that helps you. There is no federal landfill leachate PFAS regulation today, but there are landfill effluent guidelines: EPA promulgated 40 CFR Part 445 in 2000, built on equalization, biological treatment and multimedia filtration, covering conventional pollutants and a short list of organics. It missed PFAS entirely, which is no indictment of the drafters, since almost nobody in 2000 was looking.

The revision is real and it is slow. Under RIN 2040-AG40, EPA's own Unified Agenda entry projects a notice of proposed rulemaking in March 2027 (the previous agenda had it in 2026, so that date has already moved once). Add a comment period, a final rule, and then the years a new guideline takes to reach individual outfalls as permits come up for renewal, and you are deep into the next decade before a federal number governs your discharge. And your next permit renewal arrives well ahead of that.

I spent eight months of a 2023 Title V renewal on what the client had filed as a minor modification. It tripped PSD review, the schedule slipped two full quarters, and the underlying change was one they'd have made anyway. The lesson generalizes past air permitting. The cost of a permit condition gets set the day a writer puts it in your permit, and that day can sit years on either side of the day the rule authorizing it was published.

Is leachate too small a share of the loading to regulate here?

WM made this argument to DEC and the number it cited is a real one. Michigan and North Carolina studies from 2019 and 2020 put landfill leachate at somewhere between 0.3 and 10.2 percent of contaminant presence in the receiving systems, averaging 3.3 percent. Casella's Sam Nicolai put the objection more bluntly, calling the proposal "an extraordinarily expensive and wasteful approach to leachate management," and the National Waste and Recycling Association told DEC the limit may simply be unworkable.

Industry is arguing about mass. Regulators are arguing about access. EPA's 2021 detailed study sampled roughly two hundred landfills and found PFAS in leachate at 95 percent of them, 63 distinct compounds across the set. A landfill is a single pipe with a meter on it. The other ninety-seven percent sits in stormwater, in industrial pretreatment, and in products still on store shelves, and for most of it there is no permit to write at all. Offered a choice between the largest share and the share they can actually meter, permit writers take the pipe every time. That isn't fair. But it is how pretreatment programs have worked since the 1970s.

There's a second half to the pass-through argument the tonnage math skips. A water resource recovery facility was never built to destroy PFAS, so whatever doesn't leave in the effluent accumulates in the sludge, which is why EPA's biosolids work has been narrowing land application faster than any rule has. Nor does diversion get you out of it. Strip everything divertible out of tomorrow's tonnage and the cell you filled in 2004 keeps making leachate for decades, so landfill diversion programs and leachate liability run on completely separate clocks.

Where does the case genuinely weaken? At the small end, and DEC's own arithmetic shows it. Over a twenty-year operating period the department estimates self-treatment at $4.62/ton to $121.28/ton of waste disposed, and the top of that spread belongs to sites taking modest tonnage while generating a lot of liquid (a capped cell in a wet climate will outproduce an active one in a dry climate, and it takes in no tonnage at all). A facility on the wrong side of that spread is being asked to build a chemical plant to serve a closing cell. And then there's the concentrate. The rule sends it back into the landfill as solidified residue or alternative operating cover, which holds until some state decides the concentrate is its own regulated waste stream, and the thermal treatment technology handling the vapor side adds an air permit to what began as a water problem. That loop hasn't been run at scale in New York yet.

Does New York's rule stop at the New York line?

DEC doesn't think so, and it says as much in the Regulatory Impact Statement: the amendments "will pave the way for New York State to be the first state to implement such guidelines and standards." First implies second. But copying is not how this travels, and that's the part operators outside New York keep missing.

It travels through the receiving facility. Every treatment works accepting leachate today does it under a sewer-use agreement or an industrial-user permit, and every one of those documents contains an acceptance clause and a reopener. A publicly owned plant that reads the New York filing, then looks at its own biosolids outlet and its own state's direction on landfill leachate PFAS regulation, needs no rulemaking whatsoever to stop taking your tanker. It needs a letter. That decision moves at the speed of a board meeting, and long before a federal guideline exists, a good number of those agreements will have been reopened on terms nobody modeled.

Start with the two documents that already bind you. Pull the sewer-use agreement or industrial-user permit covering your leachate and read the acceptance language, the reopener, and the notice the receiving plant owes you before it stops taking the load. That notice period is the runway you're working with, whatever the rulemaking calendar says. Then commission an influent characterization across the Tables 3A and 3B analyte list, from a laboratory that will document its quantitation limits in writing, before a permit writer asks you for it. Having your own numbers in hand is what separates negotiating a compliance schedule from being handed one.

Sources & Notes

• The 99.9 percent criterion, the Subpart 363-12 structure, the one-year and two-year plan deadlines, the four-year transition for treatment works, the count of 25 active MSW and 7 active C&D landfills, and the $4.62 to $121.28 a ton figure all come from DEC's own filing: the supporting documents for 6 NYCRR Parts 360 and 363, including the Summary of Express Terms and the Regulatory Impact Statement. The blockquote above is from the RIS.
• Kramer's memo, the "cart before the horse" language, and the list of jurisdictions without delegated NPDES authority: Waste Dive's reporting on EPA pulling the PFAS wastewater permit guidance, September 18, 2026.
• Sam Nicolai's quote, the NWRA comments, and WM's citation of the 2019-2020 Michigan and North Carolina studies are from Waste Dive's account of operator pushback on the New York proposal. The 0.3 to 10.2 percent range is WM's characterization of those studies, not my own reading of them.
• For the federal rule: EPA's landfills effluent guidelines page covers the 2000 promulgation of 40 CFR Part 445, and the March 2027 proposal date is the projection in the Unified Agenda entry for RIN 2040-AG40. Projected dates in that database slip routinely, and I'd treat March 2027 as the earliest plausible date rather than a commitment.
• The detection-limit problem is laid out well in Sanborn Head's client alert on the proposed changes, which also walks through the treatment trains likely to be proposed.

Disclosure: I advise waste-to-energy and disposal clients on permitting and regulatory strategy at Renewable Waste Energy. The 2023 Title V matter above is described without identifying the client or the site, because the permit file remains open.