"The 'Clean Water Rule,' commonly referred to as the 'waters of the United States' (WOTUS) rule, was signed by Environmental Protection Agency Administrator Gina McCarthy and Assistant Secretary of the Army for Civil Works Jo-Ellen Darcy on May 27, 2015 in a picturesque signing ceremony hosted by the National Wildlife Federation on the banks of Washington, D.C.'s Anacostia River. The process that led to the rule's signing, however, was rife with legal shortcuts, predetermined conclusions, and politically-driven timelines. Passed by Congress in 1972, the Clean Water Act (CWA) gave the federal government limited jurisdiction over certain navigable waters. The statute failed to adequately define navigable waters, leaving the task to the agencies responsible for implementing the law. The legal definition of navigable waters is significant as it triggers multiple authorities under the CWA and provides the foundation of the jurisdictional authorities over navigable waters for both the U.S. Environmental Protection Agency (EPA) and the U.S. Army Corps of Engineers (Corps), which share CWA jurisdiction. Challenges to the legal scope of the term 'navigable waters' ensued after passage of the CWA, culminating in two notable Supreme Court cases in the last fifteen years. These cases upheld congressional limits on the scope of the CWA and rejected the notion of limitless federal government authority over water. In response to those decisions, the Bush Administration in 2008 issued guidance incorporating the Court's decision limiting CWA jurisdiction. However, in 2011 the Obama Administration issued its own guidance expanding the CWA's reach to regulate a broad category of wetlands."
House Committee on Oversight and Government Reform: https://oversight.house.gov/