From the 25th to 29th March 2024, first field tests were conducted with the new IoT-based water quality monitoring system. The node, which is capable of measuring temperature, pH, turbidity, total dissolved solids (TDS), electrical conductivity (EC), and dissolved oxygen (DO) was tested at the wastewater treatment plant of the Hospital for Tropical Medicine, Bangkok, Thailand. Through the use of the system, we aim to automatize the process of monitoring water parameters that can be indicators for pollution and the effectiveness of wastewater treatment.