A water supply apparatus, wherein - a mixing apparatus is provided for mixing, in a mixing container, water carried in the mixing apparatus; - relative to the mixing container, a base apparatus is arranged which has a base chamber that is hydraulically connected to a water conduit (11, 12, 13) of the water supply apparatus and which has an opening to the surroundings; - a sealing device is installed in the base chamber for closing off the opening of the base chamber from the surroundings; - the sealing device has a wall area with predetermined breaking point which has a compressive strength that is lower than the compressive strength of wall areas of other components of the water supply apparatus which, in the operating state, enclose cavities that can be filled with water, and which separate these cavities that can be filled with water from the surroundings; characterized in that - the mixing apparatus is a pressure equalization and mixing apparatus; - the pressure equalization and mixing apparatus has a mixing device (3, 4) and a pressure equalization device; - the mixing device (3, 4) serves to mix the water carried within the mixing device; - the pressure equalization device serves to restrict the pressure increase in the water; - the mixing device (3, 4) and the pressure equalization device are integrated in a container unit and have a common housing absorbing and carrying the water; - the pressure equalization device is arranged at least partly within the mixing device (3, 4); - the mixing device has a water absorbing mixing volume; - the pressure equalization device has an air absorbing pressure equalization volume; and in that - the mixing volume and the pressure equalization volume are adjacent to one another and are at least partly separated from one another by a common partition wall. - a mixing apparatus is provided for mixing, in a mixing container, water carried in the mixing apparatus; - relative to the mixing container, a base apparatus is arranged which has a base chamber that is hydraulically connected to a water conduit (11, 12, 13) of the water supply apparatus and which has an opening to the surroundings; - a sealing device is installed in the base chamber for closing off the opening of the base chamber from the surroundings; - the sealing device has a wall area with predetermined breaking point which has a compressive strength that is lower than the compressive strength of wall areas of other components of the water supply apparatus which, in the operating state, enclose cavities that can be filled with water, and which separate these cavities that can be filled with water from the surroundings; characterized in that - the mixing apparatus is a pressure equalization and mixing apparatus; - the pressure equalization and mixing apparatus has a mixing device (3, 4) and a pressure equalization device; - the mixing device (3, 4) serves to mix the water carried within the mixing device; - the pressure equalization device serves to restrict the pressure increase in the water; - the mixing device (3, 4) and the pressure equalization device are integrated in a container unit and have a common housing absorbing and carrying the water; - the pressure equalization device is arranged at least partly within the mixing device (3, 4); - the mixing device has a water absorbing mixing volume; - the pressure equalization device has an air absorbing pressure equalization volume; and in that - the mixing volume and the pressure equalization volume are adjacent to one another and are at least partly separated from one another by a common partition wall.