On March 25, 2014, the Environmental Protection Agency (EPA) and the U.S. Army Corps of Engineers (Corps) jointly proposed a rule defining the scope of waters protected under the Clean Water Act (CWA). The proposal would revise regulations that have been in place for more than 25 years. Revisions are proposed in light of 2001 and 2006 Supreme Court rulings that interpreted the regulatory scope of the CWA more narrowly than previously, but created uncertainty about the precise effect of the Court's decisions.