The invention relates to a method for operating a washer which comprises a washing chamber for accommodating goods to be cleaned, said washing chamber having in its lower portion a sump for collecting water during operation of the washer, a water inlet connected to a water tank, preferably to a water tank that is integrally, still preferably detachably, formed with the dishwasher, a pump for circulating water through the washing chamber, and a control unit for controlling a washing process carried out by the washer. In accordance dance with a first embodiment of the method of the invention, in this method: water is fed from the tank into the sump by the action of the hydrostatic pressure prevailing within the tank; the pressure within the sump or close to the sump is measured; and based on the pressure measurement the speed of the water flow is monitored and the filling level of the tank is determined, and at least one parameter and/or step of the washing process is controlled and/or indicator signals are issued to a user of the washer.