Federally Supported Water Supply and Wastewater Treatment Programs [Updated May 3, 2019] [open pdf - 1MB]
From the Introduction: "This report provides background information on the types of water supply and wastewater treatment projects traditionally funded by the federal government and the several existing programs to assist communities with water supply and wastewater treatment. For more than four decades, Congress has authorized and refined several programs to help communities address water supply and wastewater problems. The agencies that administer these programs differ in multiple ways. For example, in terms of funding mechanisms, projects developed by the Bureau of Reclamation (Reclamation) and the U.S. Army Corps of Engineers (USACE) typically require direct, individual project authorizations from Congress."
CRS Report for Congress, RL30478
Congressional Research Service: https://crsreports.congress.gov/