<p>Water security is central to economic development, equity, and climate resilience in India, yet increasing groundwater depletion, erratic monsoons, and competing sectoral demands have intensified water stress. This study examines the role of Integrated Water Resources Management (IWRM) in addressing these challenges through a case study of Karnataka, one of India’s most water-stressed states. Using policy analysis and secondary evidence, the study evaluates how IWRM principles are being operationalized in agriculture, urban supply, and governance systems. Results show localized gains in irrigation efficiency through micro-irrigation adoption, expanded wastewater reuse in Bengaluru, and improved stakeholder coordination via Water User Associations. However, fragmented institutions, weak data systems, and inequitable access continue to constrain progress. The study also identifies emerging water–energy linkages in pumping efficiency and wastewater treatment. Findings highlight Karnataka’s IWRM approach as a scalable pathway for climate-resilient water governance in India and the Global South, provided institutional integration and basin-level planning are strengthened.</p> Graphical abstract <p></p>