Abstract: A washer for utensils, such as baking pans and trays, having a spray chamber containing a movably mounted utensil rack and spray nozzles arranged to impinge upon articles stacked in the rack; a source for supplying wash and rinse water under pressure to the spray nozzles, and a water motor for moving the rack relative to the spray nozzles, the water motor comprising a waterwheel rotatably journaled in a housing, the waterwheel having a plurality of radially extending blades driven by additional spray nozzles mounted on the housing and positioned to direct jets of water onto the blades adjacent their outer ends, the additional spray nozzles for driving the waterwheel being connected to the source supplying wash and rinse water to the spray nozzles utilized to spray the articles being cleaned, the waterwheel mounting drive mechanism for moving the rack relative to the spray chamber so as to obtain complete and efficient washing of all surface of the articles being cleaned.