Filling level indicators for washer fluid containers in motor vehicles have hitherto been arranged directly on the washer fluid container or been integrated in the instrument cluster on the motor vehicle. Despite the available information, the filling of the container when the level is too low is often delayed. A filling level indicator more effectively indicates the filling level by arranging the filling level indicator in the region of the tank filler neck, whereby the filling level in the washer fluid container is only indicated to the driver when he has in any case interrupted his journey in order to fill up with fuel and is free from other activities, so that it is virtually impossible for him to be distracted.