This paper aims to develop a smart self cleaning water purifier emphasizing on sterilization function, convenient maintenance, safety, and thermal efficiency so that consumers can operate to sterilize whenever they wants and monitoring is made by quantity of water and checking water condition regularly. In addition, the self-diagnosis cleaning was made hot steam water penetrate into tubes, hot and cold storages of water purifier automatically. In general, cleaning and sterilization is needed once everyday since bacteria occurs in 24 hours and the steam sterilization is designed to function automatically or manually