Thank youTrevor Schmidt  It is very intrusive if your landlord is able to just come into your living space while you are away.

This is just what can be seen from a non-intrusive inspection, so I am sure this is just a small portion of what is going on behind the walls.  

I am not a lawyer, but let's start with the basics: The Disclosure Form in Ohio specifically addresses the question of "water intrusion."  

Just let them know you are looking for a flashing inspection and repair for a roof stove/microwave vent that might be letting in rain intrusion.

It should not be your first (and certainly not your only) line of defense against water intrusion.

A few sources I've read suggested that tree root intrusion is the only problem that a scoping will catch because cast iron and clay pipes either rust or crack from the outside in, so unless the line is actually broken at time of inspection an impending break won't be seen. 

It has not rained, there was no intrusions from the roof, sidewalls, basement, anything.  

Because I find him to be intrusive I prefer not to tell him anything.

I'm currently getting some water intrusion along that same wall in the basement.

The biggies that you don't always see (read expensive) for me in CO are stable soil/foundation/water intrusion, aluminum wiring or out of favor fuse panels, hvac if not replacing, sewer scope in most older neighborhoods, roof (which will need to be brought to code (shingles, ice dams, re-sheeting maybe) on the sale usually if it's older).