A Pico hydro power plant is one good solution to support energy independence for rural areas in Indonesia. The problem that normally emerged is the uncertainty of water debit. This may cause the damage of the Pico hydro power plant equipment. The main objective of this study is to design a water flow monitoring (WAFLOW-MT) device based on the Internet of Things (IoT). This device may help the technicians at the Pico hydro power plant in monitoring the speed of water flow at the river so that the water debit is recorded all the time. The design and development process of the WAFLOW-MT device was done through 4 stages: 1) need analysis; 2) system design; 3) system development, and 4) system testing. The data was collected from the water flow sensor and sent via IoT to the webserver thingspeak.com by 6 days duration of testing. According to the testing result, it can be concluded that the WAFLOW-MT device successfully monitored the water flow of the river.