Domestic-water supply and withdrawal system for a washstand and sampling valve for such a system

A domestic-water supply and withdrawal system for a washstand with wall-mountable angle valves (16, 18) for cold and hot water and a washstand fitting (10) which is coupled in flow communication with the associated angle valves (16, 18) via pipe or tubing sections (12, 14), characterized in that a sampling valve (2) is arranged between the cold-water and/or hot-water angle valve (16, 18) and the washstand fitting (10) and that a backflow preventer (6) is arranged between the sampling valve (2) and the washstand fitting (10).

A sampling valve (2) for a domestic-water supply and withdrawal system comprising a housing (2) having an inlet (20), outlet (22) and sampling opening (24), wherein the inlet opening (20) and the outlet opening (22) are in communication with each other via a flow passage formed in the housing (4), and wherein the housing (4) encloses a valve body movably arranged therein, which in its closing position shuts off the sampling opening (24) from the flow passage and which in an open position opens the flow passage to the sampling opening (24), characterized in that a backflow preventer (6) is assigned to the outlet opening (22).