KnowFlow is an open source water monitoring device and an education program. For the device part, KnowFlow is designed for environmental activists, researchers, students... anyone who wants to know the water quality using low cost and customized tools. It is based on arduino uno and can currently monitor 5 parameters: Temperature, pH, ORP, Electrical conductivity and Dissolved Oxygen. The data is stored on a micro SD card and can be read directly on phone by bluetooth (except for Dissolved Oxygen). All the modules are easy to change or add. Most of the sensors used are from DFRobot and Atlas Scientific, the main 2 sensor suppliers for Arduino users.