The Ogallala aquifer is contained in the Tertiary-age Ogallala Formation in the Texas Panhandle and is the primary water-bearing hydrogeologic unit of the High Plains aquifer system. The Ogallala aquifer is the primary source of water used for agricultural and municipal purposes in the Texas Panhandle. The Dockum aquifer is contained in the formations that compose the Triassic-age Dockum Group and serves as an additional source of water in the Texas Panhandle. Depth to groundwater measurements and water-quality samples were collected from 32 monitoring wells in the North Plains Groundwater Conservation District management area within the northern part of the Texas Panhandle as part of two synoptic sampling efforts, one during 2012–13 and the other during 2019–20. Groundwater-quality samples were collected for analysis of dissolved solids, major ions, nutrients, and trace elements. Selected organic compounds were analyzed in samples collected from a subset of 6 wells. Sample results for selected constituents were compared to drinking-water standards and between the two synoptic sampling times in an interpretative report. A previously published report by Baldys and others (2014) discusses the results from the 2012–13 sampling event.