Waste Piping Mystery

D107

Out of snaking the upstairs bathroom clogged line has come a piping mystery. The bathroom was re-done thirty years ago by prior owners, toilet and shower re-positioned. You can view much of the piping from below from the 1st floor bathroom which was newly installed at the same time.

I used to think that A. was sink drain, now I think D. might be sink drain. We thought behind sink there might be galvanized line, but today we could see it was PVC; but of course we can't see where sink line hits floor. D would be straightest route for sink drain.

B would be a Tee for water carried by G and C (and A, & D?) Shall I assume that all these lines are carrying water downward and none could be vents for anything on the 2nd floor?

I just noticed E today (PVC) and have NO idea what that could be especially since it disappears in subsequent photos taken at same time. Shower above had mini-vent installed by us when that galvanized piece was replaced by PVC. Plumber feels both sink and toilet must be vented at stack, which makes sense, but both A and D are headed downwards, so not sure what each one is.

Jamie Hall

That surely is... um... creative. F probably is a vent -- and nothing else. I presume G ties into D at the T? And A ties into G and C at the lower T?

But then... where does the water go from there? The big poly or maybe ABS behind G and under A -- does that come from a water closet? And goes into the CI hub. But how do G, A, and B drain?

D107

Jamie Hall said:

That surely is... um... creative. F probably is a vent -- and nothing else.

@Jamie Hall I have annotated 2nd photo to make things clearer.

I presume G ties into D at the T?
Yes.
And A ties into G and C at the lower T?
Yes, A and C run through T into G, which runs through T at B, then through F.
But then... where does the water go from there?
F, which is both a vent and a drain line, (wet vent?)

The big poly or maybe ABS behind G and under A -- does that come from a water closet?
Yes.
And goes into the CI hub. But how do G, A, and B drain?

F. then basement.

That 2" copper line is F draining into copper basement main which drains into cast iron main stack in a few feet.

Jamie Hall

Eh? In the first photo, F appears to be a continuation of D/B, then turns up? If so, how do A and C drain? Water doesn't run up hill... am I missing something? Interpreting the photo incorrectly?

D107

@Jamie Hall F doesn't turn up, it does a 90 on the same plane. Photo 1 you're looking up at the ceiling from the floor below. A,B,C,D, G all flow towards F, and then F continues in photo 2. Probably hard to discern orientation.
A construction company did this years before we came along; they should have had a licensed plumber doing this but who knows.

That 'F' (at basement level) is likely venting kitchen waste and a first floor bathroom toilet you can see its waste line in basement photo, but not sure what else F could possibly vent. Trying to figure this out to understand sporadic sewer smells and black ooze in 2nd floor sink.

I will be double-checking drain lines when shower's on upstairs to make sure it's draining where I think it is. We've added mini-vents to kitchen,1st floor bath sink, basement slop sink and all drain well. Both toilets work fine, and after we had the 2nd floor sink snaked today, that drains fine now too, though sludge tends to build up quickly.

E in photo 1 is a total mystery.

mattmia2

You are looking up at a ceiling in both pictures. Look at the ceiling j channel along the wall. Those tees where they should be wyes are likely why everything clogs up.

Jamie Hall

Vertigo. Thank you!