This chapter explores the intersection of the circular water economy and the water-energy nexus, presenting a systems-based approach to resource management that emphasizes efficiency, resilience, and sustainability. It introduces the 5Rs framework, Reduce, Reuse, Recycle, Recover, and Restore, as a practical guide for transforming linear water systems into circular models that reduce energy demand, recover valuable resources, and regenerate natural capital. The chapter outlines the environmental, economic, and regulatory drivers behind the shift to circularity, presenting global best practices through utility-led case studies. By integrating decentralized infrastructure, digital technologies, and nature-based solutions, the circular water economy aligns water service delivery with climate mitigation and adaptation objectives, contributing to long-term water and energy security.