Water has always been central to urban development, yet rising consumption, climate change, and increasing scarcity demand a rethinking of how cities manage this essential resource. This study positions WasteWater reuse as a critical strategy for advancing sustainable urban development. Focusing on the implementation of Secondary Wastewater Use Systems (SWWUS), it explores how reclaimed water can be integrated into urban planning to reduce freshwater demand, enhance resilience, and support circular economy principles. Building on concepts of water-sensitive urban design and integrated urban water management, the research tries to illustrate how WasteWater reuse in public spaces can mitigate environmental pressures while fostering multifunctional benefits through synergies with blue-green infrastructure (BGI). Case studies from Italy and China illustrate both the historical role of water in shaping cities and the contemporary challenges of WasteWater reuse across diverse contexts. The findings highlight opportunities for embedding WasteWater systems into the urban fabric as drivers of ecological health, cultural value, and urban prosperity. In doing so, it argues that WasteWater reuse is not only a technical solution but also the first step toward resilient, water-centered cities.