Smart prepaid water metering system with real-time monitoring : leak detection and online payment integration

Abstract

Urban councils in Zimbabwe still face practical water-management problems that are linked to manual meter reading, disputed bills, weak revenue collection, old pipe networks and slow response to leaks. Residents are affected as well because they often have no simple way of checking how much water they are using until a bill has already been issued. This project therefore focused on a prototype that brings together household metering, prepaid credit control, online payment, automatic valve operation, distribution-line leak detection, emergency credit and backup power. The aim was to design, build and test a Smart Prepaid Water Metering System with Real-Time Monitoring, Leak Detection and Online Payment Integration for use in the Zimbabwean urban council setting. The work was treated as a prototype study, not as a finished municipal product. Its purpose was to check whether low- cost embedded hardware and a web platform could improve visibility of consumption, control unpaid usage and support quicker response to treated-water losses. The prototype followed an engineering design and prototyping approach. The hardware used an ESP32 microcontroller connected to three YF-S201 Hall-effect flow sensors, a 12 V DC solenoid valve switched through a relay, a 16 x 2 I2C LCD, an active buzzer and a backup battery pack made from three 3.7 V lithium-ion cells protected by a 3S Battery Management System. The software side used a Flask backend, a MySQL database, HTML, CSS, JavaScript and Bootstrap dashboards, serial communication between the ESP32 and the backend, Paynow for online payment and Ngrok for remote prototype access during testing. For leak testing, two flow sensors were installed on a simulated main distribution section and treated as points placed 500 m apart. The system compared the readings from these two points to identify a possible leak or burst in that section. A third flow sensor measured household consumption. The ESP32 used the measured consumption to deduct prepaid credit, and when the balance reached zero the solenoid valve closed. Water supply was restored only after a successful top-up or after an approved emergency-credit request updated the balance. Testing was done under controlled laboratory conditions. The flow measurement tests gave an average accuracy of about 98%, with the largest observed error being 0.4 litres. The valve closed in less than one second after a zero-balance condition and reopened after credit was restored. A simulated leak produced a 5.10 L/min difference between the two distribution sensors and produced evidence on the dashboard, LCD, buzzer and email alert. Ten Paynow test transactions were completed successfully, while the emergency- credit test allowed one temporary allocation and rejected a repeat request before repayment. The results show that the proposed system is feasible at prototype level and relevant to the challenges faced by Zimbabwean councils. Its main contribution is the combination of prepaid metering, leak detection, online payment, valve control, emergency credit and battery backup in one working setup. Before any wider deployment, further work should include field testing, secure cloud hosting, stronger sensor calibration, GSM or NB-IoT communication, tamper protection, improved battery sizing and production-level data security.