The lowest floor of multi-family houses in our country has this problem - Drain Overflow Part 1

Hello everyone! Welcome to the Plumber Story Channel.

There are many small multi-family houses in Korea.
All the new small houses these days have piloti structures.
Since the parking problem is serious in Korea, I chose the piloti structure to solve the parking problem.
The first floor is a parking lot and the second floor is a house.
There are 10 houses in this small building.
There's this problem on the lowest floor of multi-family houses in Korea.

Видео The lowest floor of multi-family houses in our country has this problem - Drain Overflow Part 1 канала Plumber Story