Seepage losses (recharge) that occur within the conservation pools of Medina and Diversion Lakes infiltrate the Edwards aquifer and the upper zone of the Trinity aquifer. To quantitatively relate recharge to the Medina Lake stage, recharge was estimated from hydrological data collected within the Medina and Diversion Lake study area during 1955–2022 by using a water-budget approach. Water-budgets were prepared that incorporated data collected by the USGS and various agencies during four different periods: March 1955–August 1964; October 1995–September 1996; March 2001–June 2002; and March 2017–October 2022. A statistical analysis of the data culminated in a new log-log weighted least squares (WLS) regression equation to relate the Medina Lake stage to estimates of groundwater recharge. This data release includes an .R script that was written to perform statistical calculations in the R programming language (R version 4.3.2) to correlate the relation of Medina Lake stage (water-surface elevation in feet [ft] above the National Geodetic Vertical Datum of 1929) to seepage loss from the Medina and Diversion Lake System. The .R script works with the included hydrologic data in the MedinaLk_SeepageLoss_Analysis.csv file. The included hydrological data were collected within the Medina and Diversion Lake study area during 1955–2022.