Mystery Pipe

[BillKlineg]

Hello all,

I don't know much about plumbing and I was hoping someone could help me identify this pipe that was sticking out of the side of my house.

It is a hard black plastic (ABS?) pipe 2" in diameter. It's hard to see from the outside but inside the wall it appears to be branching off from a vertical pipe like in the second picture I got off the internet.

Behind the wall there is a bathroom but there doesn't seem to be any water or air being discharged when the bathroom is in use. There is no smell or sign of moisture at all. I do however hear the noise of running water coming from the pipe when the washing machine in another part of the house drains itself, but the water doesn't discharge from the pipe and no water flows through the vertical pipe that the pipe branches off from.

I am planning to put a stucco patch over the hole and wanted to know what I should do with the pipe opening.

Should I plug it?
Should I extend it out of the wall while patching around it?

Any help would be greatly appreciated
Bill

 

[frodo]

stick one of these in it.

 

[BillKlineg]

Thanks Frodo. That was what I thought of doing but I was just afraid that plugging it might cause some issues if the opening served some purpose I didn't understand.

Bill