A method and a computer program product controls the water supply in a sanitary installation having a cold water supply line and a hot water supply line, a valve battery, which is connected to a power supply, and a sensor unit connected to the power supply. At least one trigger means outputs an action signal to an electronic controller when activated by a user by tapping on the trigger means that is embodied as a switch or by at least partially penetrating into the detection area of a trigger means that is embodied as a proximity sensor.