In 2015, the Environmental Protection Agency and Army Corps of Engineers revised the definition of the “waters of the United States” as part of the Clean Water Rule. This revised definition was expected to increase the wetland area subject to protection under the Clean Water Act, and an economic analysis conducted by the agencies at the time showed that the benefits of the rule would substantially outweigh the costs. Under the Trump administration, the agencies now propose to repeal the 2015 Clean Water Rule and have issued a revised economic analysis in support of that decision. In the new analysis, the agencies now claim that the majority of the benefits in the 2015 analysis cannot be quantified, making it appear that the Clean Water Rule is not cost-benefit justified. The agencies have violated many of their own requirements for conducting economic analysis to arrive at this conclusion, and a more comprehensive assessment of the evidence shows that the 2015 Clean Water Rule is still cost-benefit justified. Repealing the 2015 Rule would forgo substantial environmental and economic benefits.