Water distribution within multi-unit residential housing societies is commonly unmetered, manually operated, and prone to overflow, dry-running, and undetected pipeline leakage. This paper presents the design, hardware implementation, and experimental validation of an ESP32-based IoT-enabled smart water management system that unifies non-contact ultrasonic overhead-tank automation, per-household turbine-based sub-metering with per-capita quota enforcement (135 L/person/day, as per BIS IS 1172:1993), differential mass-balance pipeline leak detection, solid-state IRFZ44N MOSFET actuation, and real-time analog Total Dissolved Solids (TDS) potability monitoring. Telemetry and control are exchanged over a full-duplex WebSocket server broadcasting 1 Hz JSON frames across a dual-mode (SoftAP + Station) Wi-Fi link to a mobile/web dashboard. A custom two-layer PCB was designed in KiCad and fabricated in-house, and the complete system was validated on a physical scale prototype of a two-household society. Experimental results show 0.0% level-measurement error after five-sample median filtering, flow-metering error within ±0.7% of the reference volume, and leak-isolation response within 1.2 s of an induced |ΔQ| = 1.4 L/min fault. The results confirm that the proposed architecture is a low-cost, cloud-independent, and scalable solution for automated, transparent, and conservation-oriented residential water management.