A heavy rain warning has been issued in most parts of South Korea, including Seoul and the provinces of Gyeonggi-do, Gangwon-do and Chungcheong-do.
The Korea Meteorological Administration warns that the Seoul metropolitan area could see one to two hundred millimeters of rain per hour until Monday.
In the city of Icheon, Gyeonggi-do Province, part of the embankment of a reservoir collapsed submerging nearby houses.
Buildings were also submerged in Gwangju and Suwon.
In the city of Anseong, to the south of Seoul, a man in his 50s was killed in a landslide Sunday morning.
Rescuers found his buried body after a two-hour search.
And in the Chungcheong-do provinces, hundreds of people had to evacuate.
A firefighter in Chungju, Chungcheongbuk-do Province went missing on his way to the scene Sunday morning, and it's believed that he may have been swept away by the rushing water.
In the Chungcheongbuk-do area alone, four people have died and eight are missing.
In Gangwon-do Province, some trains have stopped operating and in Seoul, parts of the Gangnam area have flooded.
On Saturday night, a man in his 80s died when a stream flooded in the neighborhood of Sillim-dong.
The Ministry of the Interior and Safety held an emergency meeting on Sunday where officials were instructed to make sure that pump stations across the country are ready to drain the water before it gets too high.
They were also told to evacuate residents of the affected areas and to provide shelter in ways that conform to the COVID-19 prevention guidelines.
Also Sunday evening, the Central Disaster and Safety Countermeasure Headquarters raised its emergency warning to level three the highest level.
Jang Tae-hyun, Arirang News.