The dataset contains estimates for total phosphorus flux from wastewater treatment plants that discharge to surface water within the Red River of the North Basin in the United States and subbasins. Shapefiles defining the subbasins are available as part of the same data release in which these data are published. Estimates of wastewater treatment plant total phosphorus flux (or load) were calculated by Tammy Ivanhnenko for the years 1978, 1980, 1982, 1984, 1986, 1988, 1990, 1992, 1996, 2000, 2004, 2008, and 2012. Flux estimates were based on the average discharge from the wastewater treatment plants and treatment level, both reported as part of the U.S. Environmental Protection Agency's Clean Watershed Needs Survey, https://www.epa.gov/cwns. The treatment level concentrations used for total phosphorus are based on data from a 2000 U.S. Environmental Protection Agency report (table 2-17; Tetra Tech, Inc. and Andrew Stoddard & Associates, 2000). Tetra Tech, Inc. and Andrew Stoddard & Associates, 2000, Progress in water quality-An evaluation of the National investment in municipal wastewater treatment: U.S. Environmental Protection Agency Technical Report EPA-832-R-00-008, 452 p., accessed November 5, 2015, at http://water.epa.gov/polwaste/wastewater/treatment/benefits.cfm.