This tabular dataset includes precipitation data, inflow and outflow data, and other associated data for a bioretention garden in Douglas County, Nebraska. At the Douglas County Health Center (DCHC) biorentention garden the general monitoring design corresponded to a water balance approach to characterize the inputs, outputs, and change in storage within the bioretention gardens. The components of the water balance that were measured or calculated were precipitation volume, stormwater inflow volume to bioretention garden, overflow volume, and evapotranspiration. The performance of the bioretention gardens was evaluated for a series of rainfall events. The start of an event was determined based on when rainfall began at the site. The end of an event was determined based on when the water level was equal to zero in the stilling well of the inflow flume or when the water level in the bioretention garden was zero, whichever occurred last. Evapotranspiration components were not used in the event-based analysis because this analysis was used to characterize the reduction in stormwater volume and peak discharges to the storm sewer system primarily during time periods of overflow, and these components take place over longer time periods. Change in storage was also excluded from the event-based analyses because time periods were selected to represent rainfall events such that the change in storage of ponded water was always zero.