A washing machine comprises a tub in which a drum is rotatably mounted, and a storage tank having a flow connection to the tub via a feeding line provided with a pump and a three-port valve adapted to drive the flow to the drain or to the storage tank, rinsing fluid being stored in the storage tank for subsequent reuse. The washing machine further comprises a return pipe connecting the storage tank to the tub by means of a two-port valve, on such return line an auxiliary pump being placed and being used either for emptying the storage tank or for carrying out a spray washing.