Rapid urbanization presents unprecedented challenges to water security systems worldwide, with cities experiencing significant stress on water resources due to population growth, infrastructure limitations, and climate variability. This study examines water security risks in rapidly urbanizing cities, focusing on water scarcity, unequal access patterns, and aquifer overexploitation. Through a comprehensive risk assessment framework incorporating hydrological, socio-economic, and governance indicators, this research evaluates 15 rapidly growing cities across different climate zones. The methodology employs mixed-methods approaches including spatial analysis, stakeholder interviews, and quantitative risk modeling. Results indicate that 73% of studied cities face high or extreme water stress, with informal settlements experiencing 3.2 times higher water insecurity rates than formal urban areas. Aquifer depletion rates exceed sustainable yields by an average of 45% in studied locations. The findings reveal critical gaps in integrated urban water planning, with only 27% of cities implementing comprehensive water sustainability strategies. This research contributes to understanding urban water security dynamics and provides actionable recommendations for integrating water sustainability into urban planning frameworks.