AbstractWater is at the core of the most difficult sustainability challenges facing humans in the modern era, involving feedbacks across multiple scales, sectors, and agents. We suggest that a transformative new discipline is necessary to address many and varied water‐related challenges in the Anthropocene. Specifically, we propose socio‐hydrology as a use‐inspired scientific discipline to focus on understanding, interpretation, and scenario development of the flows and stocks in the human‐modified water cycle across time and space scales. A key aspect of socio‐hydrology is explicit inclusion of two‐way feedbacks between human and water systems, which differentiates socio‐hydrology from other inter‐disciplinary disciplines dealing with water. We illustrate the potential of socio‐hydrology through three examples of water sustainability problems, defined as paradoxes, which can only be fully resolved within a new socio‐hydrologic framework that encompasses such two‐way coupling between human and water systems.