A domestic waterworks or pump having a non-return valve, which is integrated into a flow channel of the domestic waterworks or the pump or a valve housing and which has a sealing element, which is mounted in a movable manner inside the channel and which in a first position, which forms the closed position, shuts the channel and which in a second position, which forms the open position, opens the channel, the sealing element being arranged in a movable manner on a holder, which has a plug, using which the holder is fastened in a housing opening in a detachable manner, a seal being provided between housing opening and plug, the sealing element furthermore having a supporting body with a circumferential groove, in which a sealing ring sits, the supporting body being extended beyond a sealing seat and forming a guide for the sealing body there in connection with the channel, and the housing opening being provided with a circumferential outwardly protruding collar, which surrounds the plug outside the housing on the circumferential side, characterized in that an overflow channel is provided in the plug, which overflow channel is open in an intermediate position in which the plug is still mechanically fastened in the housing opening, but the seal of the plug is no longer effective, in that the supporting body has three guiding and latching legs, using which the supporting body is arranged and guided in an axially movable manner inside a receptacle which is formed by a ring, wherein the guiding and latching legs are formed in a rod-shaped manner and have latches at their free ends, so that the latches at the end of the guiding and latching legs deflect during insertion into the receptacle and widen and rebound after passing through the receptacle, and in that the supporting body is integrated in the receptacle with the integration of a coil spring, wherein the coil spring is preloaded and loads the supporting body with force with respect to the receptacle, so that in the non-installed state, the latches bear against one side of the receptacle. the sealing element being arranged in a movable manner on a holder, which has a plug, using which the holder is fastened in a housing opening in a detachable manner, a seal being provided between housing opening and plug, the sealing element furthermore having a supporting body with a circumferential groove, in which a sealing ring sits, the supporting body being extended beyond a sealing seat and forming a guide for the sealing body there in connection with the channel, and the housing opening being provided with a circumferential outwardly protruding collar, which surrounds the plug outside the housing on the circumferential side, characterized in that an overflow channel is provided in the plug, which overflow channel is open in an intermediate position in which the plug is still mechanically fastened in the housing opening, but the seal of the plug is no longer effective, in that the supporting body has three guiding and latching legs, using which the supporting body is arranged and guided in an axially movable manner inside a receptacle which is formed by a ring, wherein the guiding and latching legs are formed in a rod-shaped manner and have latches at their free ends, so that the latches at the end of the guiding and latching legs deflect during insertion into the receptacle and widen and rebound after passing through the receptacle, and in that the supporting body is integrated in the receptacle with the integration of a coil spring, wherein the coil spring is preloaded and loads the supporting body with force with respect to the receptacle, so that in the non-installed state, the latches bear against one side of the receptacle.