Abstract: An automatic dishwasher which comprises an enclosure for accommodating articles to be washed, a washing solution tank arranged below the enclosure, a hot water storage tank for containing a predetermined amount of hot water for rinsing use, a plurality of nozzles for spraying a liquid medium towards the articles in the enclosure, a motor-driven pump, a first piping connecting a discharge port of the pump with the nozzles, a second piping connecting both of the solution and storage tanks with a suction port of the pump, and a valve assembly disposed on the second piping and operable to close a first passage between the suction port and the storage tank and to open a second passage between the suction port and the solution tank during the washing operation in which the articles are washed, and to open and close the first and second passages, respectively, during the rinsing operation in which the articles are rinsed.