Plumbing Advice

It could be for a toilet I would have a plumber take a look at it and have them make a educated guess at what it is you could be opening a can of worms. If you could get a copy of the blue prints that would tell you city hall may have them as they would have needed a set no hand when the house was built.

Bill

[new but handy]

An emergency drain is defenitly worth it. If it has a P-trap I would use it. if it doesn't have one I would hammer out the slab and install one.