This is one of those things that is frustrating to the home inspector. What you see here is a flex drain. It has ridges in it, like a vacuum cleaner hose. We usually find these under bathroom sinks. If you have ever cleaned a bathroom sink drain and trap, even one with smooth pipe and a proper P-trap, you probably know that the hair and gunk is icky. Well, add the flex drain, with the ridges, and imagine how often it is blocked and needs to be cleaned. Why is this device used at all? In all cases, far as I can tell, it was done by a home-brew plumber. I cannot imagine a circumstance where a real plumber would use one of these. Specialized plumbing stores, run by plumbers (not box stores) and catering to professionals will not even sell these. Now, if someone does not know how to cut and fit simple plastic pipes, these might be real handy. But, for example in the photo below, someone who knows how to do it could put a proper P-trap in this sink in probably five minutes. It would take about one measurement, one cut, and off you go. Now, that said, the question for realtors is this: If this is found in a home, and not clogged or leaking, is this a defect an inspector should mention. Poor design or not, it is a manufactured part sold for the purpose. I have my way of dealing with this, but would like to hear what you think.
Thanks for dropping in,
Steven L. Smith
Bellingham WA home inspector
Yes,
I understand your point. Hope to get some other viewpoints and well.