ABSTRACT Obtaining dependable and economical water quality data continues to be a significant difficulty in resource-constrained areas, where traditional monitoring techniques are sometimes financially unfeasible and logistically intricate. This paper details the design, development, and field validation of an economical, microcontroller-driven electronic device for real-time monitoring of water quality in tropical surface waters, therefore solving this deficiency. The system, constructed with an Arduino Mega 2560, incorporates locally sourced sensors to assess electrical conductivity (EC), total dissolved solids (TDS), temperature, and turbidity, although pH testing is omitted due to sensor problems. Installed in four stream locations in Akwa Ibom State, Nigeria—Idim Atan, Inyang Udonwankwo, Idim Ikot Inyang, and Idim Nkap—from June 23 to June 26, 2025, the device captured 40 measurements (10 per location) over 8.5-hour intervals. Data analysis demonstrated an impeccable linear correlation between EC and TDS (R² = 1.000), confirming sensor accuracy, with EC values spanning from 600 to 820 µS/cm across locations, reaching a maximum at Idim Atan. A multiple regression model (R² = 0.513) demonstrated moderate prediction capability for electrical conductivity depending on turbidity and temperature. These findings highlight the device's potential as a reliable, accessible instrument for environmental evaluation in data-deficient tropical areas, providing insights into pollution dynamics. Keywords — Electrical conductivity, Low-cost sensors, Total dissolved solids, Tropical streams, Turbidity, Water pollution