Abstract Hydropower is a crucial no-fossil energy source, but it may cause environmental damages by huge water consumption mainly from evaporation. Facing great hydroelectric capacity and water scarcity issue in China, water loss from hydropower deserves further valuation. This study used water footprint (WF) concept, employed the gross and net approach, collected domestic data, and evaluated China’s national and regional WFs for hydroelectricity. Dam inventories were conducted covering 300 hydropower plants. WFs were calculated considering local evaporation, evapotranspiration, allocation for multi-purpose reservoirs, and were evaluated by China’s province for the first time. The results illustrated a significant regional variation. The average gross and net WF were at 3.021 (range of 0.08–122.31) L/kWh and 0.0763 (range of 0–9.638) L/kWh, respectively. WFs also showed a considerable seasonal variation with apparent regional characters. Impact of hydroelectric net WFs on local surface water was analyzed. Although hydropower WF was relatively low in China, several provinces with water scarcity issue were inappropriate for hydropower development. This research provided a comprehensive method for hydropower WF calculation and was supposed to utilize on specific region or plant. The regional results could also be a support for water management in electricity sector and for local water supply policies.