Water loss and return flows matter for water stress mitigation in China

Water is withdrawn, lost, consumed, polluted, returned, treated, reused, and traded between regions within the societal water cycle due to human activities, contributing to regional water stress. In this research, we aim to examine the impacts of the societal water cycle on water resources and explore strategies for reducing water stress in China. The results show that most provinces in China suffer from water quantity and quality stress. However, there is a significant potential to reduce water quantity stress by 36–79 % through reducing water loss and return flows. The return flows and water loss in the virtual export forms could be avoided to reduce virtual water export-induced quantity stress by 39–89 %. Agriculture and households’ return flows contribute 61–98 % to provincial water quality stress in China. The five sectors with the greatest potential to mitigate water quantity and quality stress are identified for each province, which could reduce quantity stress by 22–75 % and quality stress by 23–76 %.