Is There Only One Sewage Pipe in The Bathroom

Failed. Because the bathroom needs at least two pipes, one thick and one thin, the thick one is the sewage pipe, which can discharge all the filth, and the thin one is the exhaust pipe, which can not only remove the odor and waste gas produced by the bathroom, but also let the indoor air. The environment is more comfortable, and it can also help reduce the air pressure of the sewage pipe to ensure that the water seal is not damaged, so the two pipes each have their own functions and are indispensable.