On WOTUS Notice: EPA Gives Notice of Yet Another Clean Water Act Rule

Tracking the Meaning of WOTUS through the Years

In case you might need a refresher, here’s a breakdown of what it means to be a WOTUS through the last 20 years.

2006 – In Rapanos v. United States, SCOTUS handed down a 4-1-4 ruling that called into question the application of a 1986 rule. Rapanos v. United States, 547 U.S. 715 (2006). This SCOTUS decision implemented two competing standards for defining WOTUS.

Under the “relatively permanent flow” standard in Justice Scalia’s plurality opinion, WOTUS are “relatively permanent, standing or continuously flowing bodies of water” that are connected to traditional navigable waters, as well as wetlands with a “continuous surface connection” to such waterbodies.

Under the “significant nexus” standard in Justice Kennedy’s concurrence, WOTUS are determined based on “the existence of a significant nexus between the wetlands in question and navigable waters in the traditional sense.” Generally, the “significant nexus” standard includes more water bodies than the “relatively permanent” flow standard.

The federal appellate courts adopted differing interpretations of the Rapanos decision, with some courts following the Kennedy concurrence and others applying both Scalia’s plurality and the Kennedy concurrence.

2015 – The Obama administration issued the 2015 Clean Water Rule, which sought to clear up judicial uncertainty about which Rapanos standard applied by clearly focusing on the “significant nexus” standard. This rule faced significant challenges in the courts and was ultimately replaced by the first Trump administration’s Navigable Waters Protection Rule.

2020 – The first Trump administration adopted the 2020 Navigable Waters Protection Rule, which rejected the expanded definition of WOTUS adopted by the Obama administration, codifying instead Justice Scalia’s “relatively permanent” flow standard.

This rule clarified that “the phrase [‘the waters of the United States’] does not include channels through which water flows intermittently or ephemerally, or channels that periodically provide drainage for rainfall.” Rapanos, 547 U.S. at 739. In the arid West, the new rule’s exclusion of ephemeral features—waters that flow only when it rains or snows—eliminated a significant number of previously eligible waterways from CWA-protection. The resulting gap in federal protection would need to be filled by state regulatory efforts.

The 2020 Navigable Waters Protection Rule faced court challenges almost immediately, and its implementation was stayed by a Colorado district court judge. The Colorado stay was reversed by the Tenth Circuit on procedural grounds in March 2021. Several months later, an Arizona district court judge vacated the 2020 Navigable Waters Protection Rule. The EPA and Corps treated that vacatur as invalidating the rule nationwide.

2023 – Prior to the Sacket II decision, the Biden administration issued a Revised Definition of WOTUS that returned to the 2015 Clean Water Rule framework.

Two months later, the Sackett majority effectively invalidated parts of the Revised Definition that were based on the “significant nexus” standard. In Sackett II, Justice Alito wrote for a 5-4 majority and “conclude[d] that the Rapanos plurality was correct,” rejecting Justice Kennedy’s “significant nexus” standard as “particularly implausible,” a “theory,” and unarticulated within the statutory text of the CWA. Sackett II, 598 U.S. at 680.

In response, the Biden administration issued the 2023 Conforming Rule and struck references to the “significant nexus” standard. Instead, the rule embraced the “relatively permanent” flow standard. It included tributaries only if they are “relatively permanent, standing or continuously flowing bodies of water”; wetlands that are adjacent to “relatively permanent, standing or continuously flowing bodies of water identified [as a jurisdictional impoundment or tributary] and with a continuous surface connection to those waters”; and intrastate lakes and ponds that are “relatively permanent, standing or continuously flowing bodies of water with a continuous surface connection to [traditional interstate waters or jurisdictional tributaries].”

2025 – EPA announces interim guidance and intent to conduct a WOTUS rulemaking. Here we WOTUS again!