Washing machine and method of controlling the same

A washing machine comprising:

• a tub provided to accommodate water therein;
• a rotating tub rotatably installed inside the tub;
• a ball balancer provided in the rotating tub;
• a washing motor configured to rotate the rotating tub;
• a drain motor configured to drain water from the tub;
• and
• a controller configured to:
• based on completing a washing cycle or a rinsing cycle, drive the drain motor;
• while the drain motor is being driven, based on a water level in the tub reaching a first water level threshold, drive the washing motor for a first period of time;
• and
• based on the first period of time elapsing, stop the washing motor and the drain motor,
• wherein the controller is configured to, based on bringing the washing motor to a stopped state, drive the drain motor for a second period of time, and
• wherein the controller is configured to determine the first period of time based on an unbalance position of the rotating tub.