The U.S. Court of Appeals for the Second Circuit recently issued a long-awaited ruling confirming the legality of the Environmental Protection Agency’s (“EPA’s”) Water Transfers Rule in Catskill Mountains Chapter of Trout Unlimited, Inc. v. EPA, No. 14-1823, 2017 WL 192707 (2d Cir. Jan. 18, 2017). EPA’s Water Transfers Rule, promulgated in 2008, determined that “water transfers” are not activities that require a National Pollutant Discharge Elimination System (“NPDES”) permit. Under the rule, a “water transfer” is defined as “an activity that conveys or connects waters of the United States without subjecting the transferred water to intervening industrial, municipal, or commercial use.” Water transfers are employed throughout the country and are especially important in arid Western states, where water providers seek water supplies from rivers, lakes and streams located in entirely different watersheds.