And now I know!
I just wanted to bump this up and let everyone know that I now know what it is! After a very unhappy day of backed up plumbing, a very nice plumber spent an hour prying into this pipe on the off chance that it was a drain/septic clear out. I am, in this case, quite happy to report that it was indeed a (very odd) drain clean out.
I just wanted to bump this up and let everyone know that I now know what it is! After a very unhappy day of backed up plumbing, a very nice plumber spent an hour prying into this pipe on the off chance that it was a drain/septic clear out. I am, in this case, quite happy to report that it was indeed a (very odd) drain clean out.