Water scarcity has been the major limiting factor for crop production in Ethiopia. Improving irrigation water productivity through improved irrigation scheduling techniques becomes an important strategy. Therefore, this study was aimed to investigate the effect of gravitational and motorized irrigation methods on water productivity for selected crops in Gumara watershed, Tana Sub-basin, northwest Ethiopia. The field experiment was conducted in 2019/20 during the dry season. CROPWAT 8.0 was used as a decision-making tool to estimate crop evapotranspiration (ETc), net irrigation requirement (NIR), and irrigation scheduling. Field irrigation water measurement was done by Pump testing used for motor pump users, whereas a Parshall flume was used for gravitational users. The measurement was taken from a total of 30, 25 for onion and 5 for teff cropped fields. The measurement was done every 2 weeks for a total of 8 weeks. The comparison between the model estimates and field records on NIR of Onion-Allium cepa L. and Teff-Eragrostis tef revealed that farmers in the study areas had applied highly significantly (P< 0.01) excessive water than the crops optimum irrigation demands. The seasonal NIR for onion estimated by the model was 360.1 mm, whereas, the farmers’ mean application depth were 501.05, 496.8, and 468.7 mm from Wanzaye, Jigna, and Bebeks respectively. The model estimated NIR 364.0 mm for teff, while, the farmers had applied a mean of 459.7 mm depth of water (Bebeks). As a result, 140.75 mm, 136.7 mm, and 104.05 mm water depths were over-irrigated from the respective kebeles. Thus, farmers were extra costed 3728 birr/ha and 3146 birr/ha for fuel/kerosene from Wanzaye and Jigna respectively. Consequently, the crop water productivity (CWP) of onion was low in the study areas (4.15 kg/m3, 3.58 kg/m3, and 3.5 kg/m3 from Bebeks, Wanzaye, and Jigna respectively). The result also revealed that the BCR of onion also was low (0.94, 0.81, and 0.73 from the respective kebeles).The CWP of teff grain and straw were also found to be low (0.59 kg/m3 and 0.79 kg/m3) respectively. However, the result showed that the benefit cost ratio (BCR) of teff was higher (1.03) than onion. Therefore, the areas need immediate intervention to improve water productivity and make the system economically beneficial and ensure the sustainability of the common and scarce resources.