A warewasher (1) provided as a box-type warewasher and a method for operating such a warewasher (1) are provided. In accordance with the warewasher and method, during the adsorption phase, air is guided from the treatment chamber (2) of the machine (1) through a drying unit (40) in such a way that moisture from the airflow is absorbed by a dry material, wherein the air is then fed again to the treatment chamber (2). Furthermore, the drying device is arranged above the treatment chamber (2) so as to effectively prevent penetration of splashed water into the drying device (40).