On July 12, 2018, the U.S. Environmental Protection Agency (EPA) and the U.S. Army Corps of Engineers (USACE) issued a supplementary notice of proposed rulemaking in support of its “Step One” proposal to rescind the 2015 Clean Water Rule. The 2015 Clean Water Rule interpreted “waters of the United States” as those with a “significant nexus” under the test articulated by Justice Kennedy in Rapanos v. United States, 547 U.S. 715 (2006). In February 2017, President Trump signed an Executive Order directing the agencies to consider rescinding the rule in favor of the “adjacency” standard articulated by Justice Scalia in Rapanos. The agencies first proposed to rescind the Clean Water Rule in July 2017, but agencies received extensive comments on the proposal, including comments criticizing the scope of the supporting legal analysis. In response to those comments, the supplemental notice provides additional support for the agencies’ initial July 2017 proposal to rescind the rule. The July 2018 supplemental notice explains, for example, that the 2015 rule expanded the meaning of tributaries and adjacent wetlands to include waters well beyond those regulated by the agencies under preexisting regulations and established Supreme Court precedent. EPA and USACE propose to rescind the 2015 rule for these reasons, explaining that the 2015 rule altered the balance of authorities between the federal and state governments, contrary to the agencies’ statements in promulgating the 2015 Rule and in contravention of the Clean Water Act. This proposal only supports rescission of the 2015 Clean Water Rule. EPA and USACE still intend to proceed to “Step Two” and propose a replacement interpretation of “waters of the United States” in a separate rulemaking.