An assembly for a shower system having first and second shower members and connectable to a water supply with a supply pipe having a pipe outlet. The assembly includes an adjustable supply assembly and a diverter valve. The adjustable supply assembly includes an adapter coupleable to the pipe outlet, a supply member having a supply outlet and coupled to the adapter for movement along the axis, and a seal positioned to provide a sealed connection in adjusted positions. The diverter valve includes a valve inlet in fluid communication with the supply outlet, and first and second valve outlets in fluid communication with the first and second shower members, respectively. The shower system is mounted in an enclosure having a wall. The adapter connects to the pipe outlet on one side of the wall, and the diverter valve is located on another side of the wall.