A valve arrangement comprises first and second valves mechanically interconnected for synchronous operation with one another so as to be switchable by a single action between first and second fluid flow configurations. The first configuration provides a first path for first fluid to flow from a first inlet to a first outlet and a second path for second fluid to flow from a second inlet to a second outlet. The second configuration provides paths for first fluid to flow from the first inlet to both the first and second outlets while closing the path from the second inlet. In one application, the arrangement allows a convenient method of disinfecting a water-consuming appliance such as a shower.

A valve assembly for a shower/tub system is provided. The assembly includes a valve body assembly having a molded base, a first inlet connection fitting configured to fluidly attach a first fluid source to the molded base, a second inlet connection fitting configured to fluidly attach a second fluid source to the molded base, a first outlet connection fitting configured to fluidly attach a shower fixture to the molded base, and a second outlet connection fitting configured to fluidly attach a tub nozzle to the molded base.