A pressure container includes a first casing, a second casing, and a sealing member. A deformable membrane is mounted in the first casing, defining a water chamber that is communicated with a water inlet in the first casing. An air chamber is delimited by the deformable membrane and the second casing. The sealing member includes an inner ring, an outer ring surrounding the inner ring, and a connecting ring connecting the inner ring with the outer ring. The inner ring, the outer ring, and the connecting ring together define a first groove and a second groove respectively on two sides of the connecting ring. A flange on an end of the deformable membrane and an open end of the first casing are sealingly received in the first groove. An open end of the second casing is sealingly received in the second groove.