S. Rept. 117-17: To Amend the America's Water Infrastructure Act of 2018 to Expand the Indian Reservation Drinking Water Program, and for Other Purposes, Report to Accompany S. 421, April 28, 2021 [open pdf - 334KB]
From the Purpose: "The purpose of S. 421 is to expand a program to carry out projects that connect, expand, or repair existing public water systems or improve water quality, water pressure, or water services on reservations in the Upper Missouri River Basin and Upper Rio Grande River Basin."
S. Rept. 117-17; Senate Report 117-17
US. Government Publishing Office: http://www.gpo.gov/