Abstract: A water closet assembly adapted to be mounted on any one of a variety of bases for discharge of waste material into a drainage system, a holding tank, or the like, and which includes features for making optimum use of the flush water. The assembly includes a bowl and a pivotally mounted pan for closing the discharge outlet of the bowl and shaped so that it can provide a water seal when the pan is in its closed position. The pan can be tilted to an open position to discharge the contents of the bowl, and the actuator mechanism for tilting the bowl is operable to open a valve so that flush water will flow into the bowl in timed relation to movement of the pan. The bowl and pan are shaped to make most effective use of the flush water and to provide a desired water spot in the bowl, and an accumulation chamber is provided to measure a desired quantity of water for refilling the pan after a flushing operation.