Should drains go up or down?
Of course you know the answer to that.
I expect most elementary school children know that drains go down.
Now, this photo is the end of a long drain line.
It begins at a newly-installed "kitchen" in a basement. From there it travels a good 20' to finally attach to this drain stack.
For most of the drain the horizontal tube is angled upward.
And where it attaches to the stack the fitting is upside down! The angle of the connection should be pointing down, of course!
The installer had a 50/50 shot at getting it right and chose poorly.
And does the white PVC plastic seal well when it is glued to the black ABS tubing? Not really. They each expand and contract at different rates, and the glue used for one does not work well with the glue for the other. These connections sometimes leak. But this comment is an aside.
So what do we have? A basement "kitchen" installed without a permit, with a sink that drains upward, uses the wrong materials, connects to the drain in the wrong direction, and glugs when the water is turned on in the sink. Why? Because air bubbles go UP!
Yes, physics works every time.
My recommendation: if your client is really excited there is a new kitchen in the basement, check to see if there was a permit pulled and closed for the work. And you might also want to bring an elementary-school child with you to see if the angle on the drain is, um, downward. Because, after all, drains do best when they go DOWN.
Jay Markanich Real Estate Inspections, LLC
Based in Bristow, serving all of Northern Virginia.
Office (703) 330-6388 Cell (703) 585-7560