A dishwasher having a tub at least partially defining a treating chamber, a liquid spray system, a liquid recirculation system fluidly coupling the treating chamber to the spray system to recirculate wash liquid from the treating chamber to the spray system, and filters capable of removing particles from the wash liquid. The filters include a microfilter fluidly coupled to at least one of the recirculation system and the spray system and an ultrafilter fluidly coupled to an outlet side of the microfilter.