These data were created as part of a hydrologic study to characterize groundwater budgets and water quality in the Diamond Valley Flow System (DVFS), central Nevada. This dataset represents evapotranspiration (ET) units derived from the mean Enhanced Vegetation Index (EVI) calculated from two Landsat 5 Thematic Mapper scenes from the summer of 2010. ET units were defined within the DVFS groundwater discharge area (GDA) to group areas characterized by similar phreatophytic vegetation type and cover and to extrapolate site-scale groundwater ET estimates across the study area. This dataset represents three ET units: shrubland, grassland, and playa. The shrubland unit is composed of low to high density phreatophytic shrubs and bare soil while the grassland ET unit is composed of grassland, meadow, and marshland vegetation assemblages. The ET units were developed using a combination of EVI and site scale discharge measurements. The data were used to evaluate and estimate groundwater discharge by evapotranspiration in the study area. ET unit delineations reflect general spatial changes on the landscape and are not intended to be exact delineations of plant communities or soil conditions.