Population and economic growth cause an increase in water demand leading to ever-increasing water shortage and water crisis. The paper presents China’s future long-term changes in water demand driven by socio-economic development based on the construction of a water demand model. At the national and state or provincial level, the water demand model was calibrated and validated with historical data involving developed countries and developing countries, respectively, which exemplifies the feasibility and applicability of the model. Through analyzing the historical data and predicting the future water demand, the following conclusions are obtained. First, total water use in 2013 is not peak water. Second, total water demand is projected to continue increasing to an extent, which would not surge for the next few decades. Third, peak water of around 630 billion m3 may appear in 2026 or 2027. Fourth, the peak water will not be beyond 700 billion m3 issued by the National Comprehensive Water Resources Plan from China, even at the possible peak of population. In general, the water demand model can inform early intervention to prepare for times of scarcity and help track the effectiveness of water policy and management activities.Supplementary informationThe online version contains supplementary material available at 10.1007/s11356-022-21472-8.