This U.S. Geological Survey (USGS) Data Release provides derivative statistics of water used by Kansas public-supply systems in 2015. Gallons per capita per day is calculated using self-reported information in the “Part B: Monthly Water Use Summary” and “Part C: Population, Service Connections, and Water Rates” sections of the Kansas Department of Agriculture, Division of Water Resources' (DWR) annual municipal water use report (see appendixes at http://dx.doi.org/10.3133/ds964 for an example of a municipal water use report form.) Percent unaccounted for water is calculated using self-reported information in “Part B: Monthly Water Use Summary” of the DWR’s municipal water-use report. The published statistics from the previous 4 years (2011–2014) are also shown with the 2015 statistics and are used to calculate a 5-year average. Derivative statistics of 2011, 2012, 2013, 2014, 2015, and 5-year averages for gallons per capita per day (gpcd) are also provided by the Kansas Water Authority's 14 regional planning areas, and the DWR regions used for analysis of per capita water use in Kansas. An overall Kansas average (yearly and 5-year average) is also calculated. Kansas state average per capita municipal water use in 2015 was 105 gpcd.