Design and Implementation of an IoT Based Water Quality Monitoring System for Water Treatment Applications

The increasing demand for clean, safe water has intensified the need for reliable, continuous water-quality monitoring systems in water treatment processes. Conventional water-quality assessment techniques are generally performed manually and intermittently, which limits the capability to capture rapid variations in water conditions. In this study, the design, development, calibration, and experimental evaluation of an Internet of Things (IoT)-based water-quality monitoring system for real-time and remote assessment are presented. The developed system integrates temperature, pH, turbidity, and total dissolved solids (TDS) sensors with an ESP32 microcontroller, through which measurement data are wirelessly transmitted to a cloud-based platform for real-time visualisation and historical data analysis. Experimental testing and calibration were conducted under controlled conditions, using clear water as the reference medium, and sensor outputs were compared with those from standard laboratory instruments. The results demonstrate that the proposed system exhibits high measurement stability and repeatability, as indicated by low standard deviations, narrow measurement ranges, and small deviations from reference values. Temperature measurements were characterised by a standard deviation of approximately 0.045 °C with an uncertainty of ±0.023 °C, while pH readings remained constant throughout the testing period, indicating excellent repeatability. TDS measurements showed limited variability, with relative uncertainties below 0.3% and accuracy deviations not exceeding 1.32%. Overall, reliable system operation was achieved, with stable data transmission and effective real-time monitoring realised through a web-based dashboard. It is therefore concluded that the proposed IoT-based system provides a precise, low-uncertainty, and costeffective solution for continuous water-quality monitoring in small-to medium-scale water treatment applications.