A Wireless Sensor Network (WSN) based on the ZigBee is proposed and implemented for the water level detection based on the range scanning using ultrasonic sensor and aim to provide flood prediction. The built sensor nodes reports < 0.52% average error for the distance test within 0.20m to 4.00m. All prototype sensor nodes in this work are powered up by a single standard 3.70V battery and least for operation of ∼100 days. Such water level detection capability enables the application of surface drainage monitor and flood detection with simple data analysis approaches. An experiment is setup with variable flow-in water and drainage simultaneously to verify performance of water level detection and demonstrate the flood prediction capability.