Ten of the deaths have occurred in Sancheong in the southern part of the country. People have also died in Gapyeong in the north and in Seosan in the west. Nine people are still missing.
The heavy rains, which arrived in the country on Wednesday, have caused landslides and floods.
Over 14,000 people in 15 major cities have sought shelter from the storm in recent days. Thousands of property damages have been reported.
New rain is expected on Monday, but the authorities have lowered the warning level one step from the highest level.
