Our Flood Warning System is a web interface with water level monitoring and localized flood warning. By combining the Smart Manhole Cover, the administrator can get precise water level information and perform quick reactions like rescuing, manhole cover repairing and drainage repairing. In our Smart Manhole Cover, an accelerometer will be included to detect abnormal situations. For example, it will alert the administrator when the angle of the manhole cover is higher than a specific value which means it is not installed correctly. A water-proof ultrasonic sensor will also be included to check the water level in real-time. Then, it has network connectivity to upload all the information to the database and this data will be represented on the webpage. GPS sensor will be used to locate the position of the manhole cover, which can work with a localized flood warning and repair the drainage quickly. With our Flood Warning System, the related department can deal the emergency faster due to the precise location and real-time monitoring. It will help them save more time in rescuing and repairing with the assistance of our system.