The Ankeny, Iowa wastewater treatment facility (WWTF) was decommissioned in November 2013 providing a unique opportunity to characterize the impacts of WWTF discharge on water quality at the surface-water/groundwater interface in a shallow, unconfined alluvial aquifer. The Ankeny WWTF discharged treated effluent for nearly forty years into Fourmile Creek, located in Ankeny, Iowa. Dataset includes site information (Table 1), analytical methods (Table 2), piezometer water level elevations (Table 3), trace and major element concentrations collected from 2011 to 2013 before the WWTF shutdown (Table 4), and trace and major element concentration collected from 2013 to 2014 after the WWTF shutdown (Table 5).