The utility model discloses a water heater, include: the inner bag, the inner bag has the drain, the blow off pipe, sewage pipe connection includes in drain, blow off pipe: drain valve pipeline section, drain valve pipeline section have the play water route with the drain intercommunication, and the drain valve pipeline section is built -in to be equipped with the drain valve, and the perisporiumof drain valve pipeline section is formed with the spout, and the drain valve includes: deciding the ceramic chip and moving the ceramic chip, the periphery wall that moves the ceramic chip is equipped with first connecting portion, the knob, a valve cove. The handle. According to the utility model discloses water heater moves the ceramic chip through the rotate handle knob with the drive and rotates between the primary importance and the second place to the switching that water route on -state and closed condition has been realized, this water heater convenient to use, simple structure.