She closed the door again without saying anything and watched a very large spider disappear down the waste pipe of the bath.

The most likely reason is a blocked waste pipe.

They also stop insects crawling up the waste pipes.

Only on the suggestion of another plumber did he agree to bolt the waste pipe to the wall so it couldn't move.

Too bad they don't have a waste pipe in there.

Up on the roof of buildings there's an open waste pipe that lets the odor out.

There is a small creek that comes out into the river through the same waste pipe.

Or you can use lengths of 15 or 25mm plastic waste pipe.

This will help prevent freezing air blowing up the open ends of the waste pipes.

Then we have secretly converted certain waste pipes to run the other way!