A method of operating a dishwasher includes a tub that at least partially forms a treating chamber and a reuse tank fluidly coupled to the tub for storing liquid from the tub for subsequent reuse in the treating chamber. The method includes supplying liquid from the reuse tank to the tub, sanitizing liquid in the tub by heating the liquid to a sanitizing temperature by operating a heating element located in the tub and maintaining the liquid at or above the sanitizing temperature for a sanitizing time period sufficient to sanitize the liquid, and supplying the liquid in the tub to the reuse tank after sanitizing to sanitize the reuse tank.