<p>Effective water management and policy play a critical role in shaping society’s evolving relationship with water. Yet, the growing impacts of water-related risks worldwide show that many responses remain ineffective, often leading to unintended consequences that undermine stated policy objectives. These contradictions—referred to in the literature as water paradoxes—occur when well-intentioned efforts to manage water backfire. This Review argues that researchers should better characterize these paradoxes, and practitioners must integrate them in decision-making processes and economic evaluations of water policy. Four key paradoxes are examined: value, supply, efficiency and data. For each, relevant examples are highlighted, policy implications are explored and potential approaches for addressing them are suggested. Water management and policy should focus on addressing these paradoxes, rather than pursuing grand visions and missions detached from context.</p>