US Patent 7784133 Washing machine and water level control method thereof

A washing machine and a water level control method thereof that can supply an appropriate amount of water based on the amount of laundry using a conventional water level sensor even when the washing machine has a holeless rotary drum. The water level control method includes supplying water between the water tub and the rotary drum, introducing the supplied water into the rotary drum, discharging the introduced water out of the rotary drum, and detecting the water level of the water remaining in the water tub, and comparing the detected water level with a predetermined water level and, when the detected water level is below the predetermined water level, resupplying water between the water tub and the rotary drum until the detected water level reaches the predetermined water level.