WOTUS supplement floats a perennial-flow test for 'relatively permanent'

The Environmental Protection Agency and the Department of the Army published a supplemental notice of proposed rulemaking on 9 September 2026, reopening two definitions from their November 2025 proposal on the scope of the Clean Water Act and adding a third.¹ The agencies received “approximately 220,000 public comments on the NPRM” and state they “are not proposing to supplement other portions of the initial proposed rule” (see EPA proposes to define the words Sackett left undefined).¹² The reopened definitions are “relatively permanent” and “continuous surface connection” — the two phrases the Supreme Court used in Sackett without defining — and the notice adds “a definition of the term ‘perennial,’” which would renumber the definitions already proposed.¹³ Nothing is settled by this notice: the agencies “continue to consider the regulatory options proposed in the NPRM in tandem with the consideration of these supplemental regulatory options.”¹ They report that some commenters said the proposal is “consistent with Sackett,” while “[o]ther commenters opposed the proposal, stating, among other things, that the proposed rule would increase regulatory uncertainty and adversely impact water quality.”¹ Comments close 9 October 2026, under the same docket, EPA-HQ-OW-2025-0322.¹

1. The supplemental option is narrower than the one it supplements, with two exceptions rather than one. In November the agencies proposed that “[r]elatively permanent” mean waters “standing or continuously flowing year-round or at least during the wet season.”² The supplemental option would drop the second limb, defining “relatively permanent” to mean “perennial bodies of water,” with “perennial” meaning water present “every day of the year during ordinary conditions.”¹ The agencies say they “have modified this approach to allow for two exceptions from year-round flow.”¹ A water “does not lose its relatively permanent status if it dries up as a result of anomalous events such as drought or dry spell” — that limb carries no time limit. Separately, a water “also does not lose its relatively permanent status if it dries up for no more than a single period of up to 30 consecutive days in any given year as a result of non-anomalous events resulting in a temporary interruption such as low tide or a regularly occurring dry spell.”¹ On the non-anomalous limb the agencies spell out the arithmetic: two separate ten-day interruptions in a year would disqualify a water that a single thirty-day interruption would not.¹

2. Where the agencies cite Rapanos footnote 5, they cite it for the exceptions rather than for the perennial requirement. The supplemental notice quotes the footnote twice, both times in its discussion of “continuous surface connection,” and both times the quotation is the same and ends at the same place: “By describing ‘waters’ as ‘relatively permanent,’ we do not necessarily exclude streams, rivers, or lakes that might dry up in extraordinary circumstances, such as drought.”¹ The footnote continues, in part: “We also do not necessarily exclude seasonal rivers, which contain continuous flow during some months of the year but no flow during dry months.”²⁴ The agencies’ own November proposal quoted the footnote including that sentence, and used it to explain why they were declining the perennial-only approach they now propose: “limiting the scope of relatively permanent waters to perennial streams would exclude waters that the Rapanos plurality stated are ‘not necessarily exclude[d]’.”² In the same passage they noted the argument the other way — that “the absence of an explicit reference to such ‘seasonal’ streams in Sackett could be interpreted to mean that Sackett defined the scope of ‘relatively permanent’ to exclude such water features.”² The supplemental notice does not reproduce the seasonal-rivers sentence anywhere, and the point survives in it only as a summary of what “a different commenter stated.”¹

3. The agencies ground the thirty-day figure in predictability, not hydrology. They “are choosing to propose a temporal qualifier of 30 consecutive days because it most closely aligns with the regular and predictable nature of a ‘non-anomalous’ dry spell event that, for example, may occur over the course of a month in any given year.”¹ They also “seek comment on whether any other numeric threshold may be more consistent with Sackett and the Rapanos plurality.”¹ Their stated ground for the narrowing does not rest on footnote 5 at all: the modifier “‘relatively’ qualifies the term ‘permanent,’ but it cannot cancel it out altogether,” and “‘relatively’ cannot stretch the meaning of ‘permanent’ to the point that ‘permanent’ would encompass flow for significantly less than the majority of the time.”¹ The parallel option for “continuous surface connection” carries the same allowance and adds a further limit: “Only the portion of the wetland that is indistinguishably part of the jurisdictional water would be itself jurisdictional.”¹ On reliance interests the agencies write that they “may not utilize reliance interests as a way to skirt Sackett’s ruling,” while acknowledging that “the past eleven years have included five rule revisions, a major Supreme Court decision, a memorandum to the field, and a constant stream of lower court rulings, injunctions and vacaturs.”¹

4. Effects remain unquantified, and the agencies point to where they said so before. This is “a significant regulatory action that was submitted to the Office of Management and Budget (OMB) for review prior to issuance of both the NPRM and again prior to issuance of the SNPRM,” and it is “expected to be an Executive Order 14192 deregulatory action” providing “burden reduction by narrowing the scope of waters that are jurisdictional under the Clean Water Act.”¹⁵ But “[t]he lack of national data sources that allow for a reliable depiction of the baseline limits the agencies’ ability to estimate the economic impacts of the proposed action,” a limitation they attribute to section 1.4 of the proposed rule’s Regulatory Impact Analysis and state “is also the case for the supplemental action.”¹ Without a quantitative baseline “the agencies struggle to provide quantitative estimates of potential avoided costs and forgone benefits of the supplemental options to an appropriate degree of accuracy.”¹ The agencies add that they “are not relying on the economic analysis performed pursuant to Executive Orders 12866 and 13563 … as a basis for this supplemental notice.”¹