It is always fun to get under a home and check things out. Maybe it’s because many do not bother to look under a home that things go unquestioned. I recently came across this puzzler while looking at a different issue.
The arrow shows the flow of the main drain line, but the rest is a mystery.
The white PVC pipe is not usually found glue to the black ABS pipe; it went down through the plywood and is not known where it goes. The fitting that it is attached to is odd also. The way it is installed, with the arm facing down, forces anything running down the main pipe to flow into this smaller white pipe.
If it were intended to flow down, the black fitting is backward and should be at least the same size as the main pipe. Judging by the work done in the area, this is not an original plumbing job – it was changed. It is not even close to be a professional installation.
Since the home was a short sale and purchased as-is, the new owners may have to get this fixed in the future. I can see this being an area of clogging that will need attention if there is a high volume of use in the home.
I hope they call me, I’m real curious to see why this was done. Digging around for answers sounds like fun!