The Environmental Protection Agency and the Department of the Army’s Navigable Waters Protection Rule (NWPR): Definition of “Waters of the United States” became effective on June 22, 2020 in 49 states and all US territories. A preliminary injunction has been granted for the state of Colorado. Federal jurisdiction in Colorado will be determined using the 2019 Rule (the recodification of the 1986 Regulations) and associated 2003/2008 (SWANCC/Rapanos) guidance documents. The NWPR establishes the scope of federal regulatory authority under the Clean Water Act. The NWPR includes four simple categories of jurisdictional waters and provides specific exclusions for many water features that traditionally have not been regulated. The Federal Register notice is available at https://www.federalregister.gov/documents/2020/04/21/2020-02500/the-navigable-waters-protection-rule-definition-of-waters-of-the-united-states. Additional information about the rule can be found on the EPA’s website at https://www.epa.gov/nwpr.