An automatic service water tap is disclosed in which a battery operated motor is provided for controlling a water supply valve in response to the presence or absence of an object positioned within the range of an infrared generating and detecting system mounted in the tap. The valve operates using only a small amount of electric power under the control of a circuit which draws no electric power once the valve is moved to its opened or closed condition. Thus the consumption of the electric power is minimized to almost zero and the valve can be utilized for a long period of time only with a small single battery.
