Abstract: A faucet, such as a mixing valve (32), is connected to plumbing pipes through a fixture (7) adjustably received in a bore (19) of a fitting member (4) mounted in a housing (5). The position adjustable fixture (7) has two longitudinal ducts (28, 30) provided with duct inlets (36, 38) opening into ring grooves (37, 39). Sealing rings (40) on the fixture separate the duct inlets and grooves in pairs for keeping cold and hot water apart upstream of the mixing valve. The duct inlets communicate through ports (45, 47) with chambers (12, 14) in the fitting member. The chambers in turn are connected to the plumbing pipe to provide a separate through flow connection between the pipes and the mixing valve separately for the hot and cold water.