IoT-based smart water billing system for accurate consumption monitoring and fair distribution.

Accurate water consumption measurement and equitable billing are vital for sustainable water resource management, especially in regions facing scarcity and uneven distribution. Conventional systems, which often rely on shared mechanical meters, fail to provide individual usage data, leading to disputes, waste, and inefficiencies. This paper presents the design and experimental validation of a low-cost, IoT-enabled Smart Water Billing System (SWBS) that delivers real-time consumption monitoring, adaptive calibration, and automated proportional billing. The proposed system integrates an ESP8266 NodeMCU, YF-B1 Hall-effect flow sensors, and anomaly detection algorithms to ensure precise measurement and early leak detection, where the IoT functionality of the prototype is realized through the Wi-Fi-enabled NodeMCU, which transmits processed consumption and status data to a remote backend using HTTP-based communication for cloud-connected logging and monitoring. A multi-stage calibration method was developed to maintain accuracy across diverse flow rates, reducing measurement error to below 3%. Experimental results confirm that the system reliably tracks individual unit consumption, supports scalable deployment in multi-unit buildings, and provides transparent billing through wireless data transmission. By combining affordability, accuracy, and real-time analytics, the SWBS offers a sustainable solution for modern urban water management, promoting conservation and fair resource distribution.