Have the professional plumber attest to the condition of the plumbing and what he pulls out that may be attributing to the clog. 

As far as the 2-3% "appreciation" (mostly attributable to inflation) I could care less.

So how much of your bad experience with out of state rentals could be attributed to that vs. a fundamental flaw in the business model?

I copy and pasted comments from an article/blog that was attributed to an Ali Boone.

For example, what percentage of your crap rate is attributable to v&c?

I think his point is that the President has less control than people attribute to them.

The small investors don't like small apartments in the large investors don't like them either at least that's what I attribute My Success to with the ones that I have.

The bulk of the differences is in the remodeling finishing, the staging, the marketing, and sales; and all of these things are purely attributed to my listing agent (who handles all these things).

So I would absolutely attribute my success to the degree that I earned even though I don't use it professionally. 

In short, yes this does affect value in a negative way but the degree will be based on your location and market as well as how much of the total property value is attributable to the land itself.