Flood is a nature disaster which often happened in this world especially in Indonesia. This flood can be happened in flood vulnerable area, can cause disadvantage on the area. Flood can be happened cause high volume of water in river or lake, where the dam or irrigation can no longer accommodate the volume of water. The main causes of flooding are waterways that are blocked by al lot of garbage dumped carelessly by the community, illegal logging which can trigger flooding. Based on these problems, the researchers focus on the water level which during the rainy season. Therefore, the researchers made an IoT based flood detection system using two microcontrollers ultrasonic sensor and water level sensor as a measure of the water l...