A pump includes a housing, a water inlet pipe coupled to the housing and configured to receive washing water, a water outlet pipe coupled to the housing and configured to discharge washing water, an impeller located in the housing and configured to cause washing water to be transferred from the water inlet pipe to the water outlet pipe, a heater that is coupled to the housing, that is configured to heat washing water in the housing, and that is configured to generate steam based on heating washing water, and a steam discharge pipe coupled to the water outlet pipe and configured to discharge steam generated by the heater.