AskCodeMan

Any idea what this could possibly be for?? Can't think of any reason its necessary. The seller wasn't home to inquire.

Looks like PEX off of the tail pipe and then connects to copper in the back of the cabinet.

No idea where or how it terminates.

David McCabe

Floor drain trap primer.

Whenever water is used at that sink, some of the water goes out and down the piping, which most likely goes to a floor drain, and helps keep the floor drain primed and not evaporate dry.

Was there a floor drain in that room, or maybe in the room on the other side of the wall?

Is that an AAV, or is it a mechanical vent? AAVs are permitted, mechanical vents are not (except in manufactured homes and RVs).

I was thinking the same thing but I saw no floor drain.
Its a 2 story townhome and the laundry equipment was wisely installed on the 2 floor across the hallway with no pan or visible drain.
I did not move the washer to check under it though. I suppose its possible there is a drain under the washer I couldn't see but I also didn't notice any slope to the laundry room floor.
I'll just have the buyer inquire about it from the seller.

Thanks.