Flood is one of the most often disaster that creates unexpected damages for people living in Jakarta. In order to prevent the disaster, monitoring is one of the most useful systems to keep Jakarta away from flood and simplify the work of water gate operator. Therefore, water level monitoring and water gate controlling can be used to prevent flood. The main purpose of this research is to create an internet based system that is able to monitor the water level and control the water gate. The water level can be displayed via website as well as the water gate controlling. The first problem to solve is to make a system communicate through the internet such that the water level can be monitored. This system can be divided into two parts, i.e. hardware and software. The hardware part consists of modules connected fully to a monitoring system. The software part consists of a database and a web server to make it able for the operator to monitor through the website. The accuracy of this system is about 70%, because the data-sending delays still occur from hardware to software The final result of this water level monitoring system is an accurate data communication between the hardware and the software.