A spray assembly for an automatic dishwasher is provided comprising a conduit system for receiving pressurized washing liquid, and an elongated spray arm including an upper surface and a lower surface. The spray arm includes a dividing wall between the upper surface and the lower surface. The spray arm includes a plurality of orifices formed in the upper surface and the lower surface for distributing the liquid throughout the dishwasher. The dividing wall and the upper surface define an upper interior compartment and the dividing wall and the lower surface define a lower interior compartment. The conduit includes a water feed system and a water diverting mechanism for selectively diverting water into the upper compartment, the lower compartment, or both the upper and the lower compartments.