On February 4, 2015, the U.S. Senate Environment and Public Works Committee and the U.S. House Transportation and Infrastructure Committee questioned EPA officials about a proposed rule to redefine the term "waters of the United States" for purposes of the Clean Water Act. If an area has U.S. waters on it, then that area is subject to EPA regulation and permitting.

The proposed rule is a response to the U.S. Supreme Court's decisions in Solid Waste Agency of Northern Cook County v. U.S. Army Corps of Engineers and Rapanos v. United States, which have made it difficult to determine what exactly "waters of the United States" means.

The EPA believes the proposed rule would reduce confusion and uncertainty, thus ensuring quicker responses to requests for permits. Opponents of the rule, however, contend that the rule expands the EPA's jurisdiction reach beyond the boundaries set by the Clean Water Act and takes too much power out of the hands of the states. Therefore, opponents argue, permitting would become more difficult and expensive, as there are no time limits on when the EPA must respond to requests for permits.