On February 14, 2019, the US Army Corps of Engineers and US EPA (Agencies) published in the Federal Register the proposed rule to revise the definition of “Waters of the United States,” the term that identifies the scope of federal jurisdiction under the Clean Water Act. The proposed rule is the second step in a two-part process to revise the definition, consistent with one of the first Executive Orders issued by President Trump. The Clean Water Act prohibits the unpermitted discharge of pollutants, including soil or fill material in water bodies, wetlands and even some normally-dry lands. Accordingly, as the definition of waters of the United States (WOTUS) expands, so does the federal government’s control over construction and other activities affecting these areas. The Agencies note that they are attempting to “preserve the traditional sovereignty of States over their own land and water resources[,]” and the proposed rule is widely expected to narrow the overall number of waters subject to federal jurisdiction.