Abstract: A drain valve device mounted on the bottom of a pressure tank for the purpose of disposing of unwanted, accumulated waste liquids in the tank. The valve portion of the device is of a type comprising a stem-mounted disc moving longitudinally against, or away from a valve seat in the process of closing or opening the valve, rspectively. Movement of the stem is achieved by means of a pivotally mounted valve operating lever, or by air pressure. The valve includes as special features thereof limited contact between the disc and the valve seal; a specially positioned valve seat which provides a pressure relief safety feature; a non-jamming spring configuration with positioning means therefore, and a self-aligning stem. In one of the preferred embodiments, a constricted opening is provided in the outlet of the valve to create an audible signal and to reduce loss of pressure when the valve is in its open position, draining the tank.