Plants need sufficient water resources to be healthy and fertile. Excess amount of water and less mount of water supplied to plant may cause the plant to wither and die. Past research has focused on the method on how to watering the plant water on the right time with the right amount of water. This research focused on how to develop an auto watering system using Arduino that watering plant at the right time with the right amount. This home based system is to facilitate human in watering plant without involving any manpower. To develop a fully automated system that intelligently measures the soil moisture, different approaches of methods used in varying fields were reviewed. the most suitable system had been selected to be a source of ideas and guidance. An own idea proposed to improve the approaches of existing systems. The final components and materials needed to support an efficient auto watering system was obtained by analyzing and testing the prototypes. A plant auto watering system using Arduino is a system that facilitates human in watering the plant.