Abstract: The amount of water discharged from the tank of a flush toilet is controlled in a stepless manner by means of a rotary volume control lever concentric with the usual flushing handle. The volume control lever is connected with a slider on the arm of a float which floats at the surface of the water in the tank. The slider is connected by a lost-motion connection with a closure for the discharge opening of the tank. When the water level in the tank falls to a level determined by the position of the slider on the float arm, the closure, which has been opened by operation of the flushing handle, is closed to prevent further discharge, thereby conserving water.