After a long day of work: to unplug another's toilet, to reset switches on the electrical panel, to call the roofer to inquire about checking leak - none of these are in any way relaxing.  

I had one pour concrete down the toilets because they were pissed at getting evicted.

Common moisture problems include pipe leaks, roof leaks, sewage back-ups, and over flowing toilets / sinks / bathtubs.

They can run generators and use portable toilets but that would cost you more in the long run.

A couple months ago I did a 4x8 bathroom in about 2 hours, that included pulling and resetting the toilet.

I'm guessing you don't want to run the owner/op thing past your wife :D  And you know they blur out those crap-filled toilets on HGTV?

After a few years of dealing with toilets, leaking this and that, renters not willing to change bulbs etc...

I picked up a floor mat, shower curtain and toilet mat for $5 at big lots.

I haven't made a purchase yet but plan on buying distressed homes and fix them up for rentals.One nightmare that's kept me awake is the idea that the person foreclosed on has poured concrete down the shower/toilet/any other drain.1) How do you check for this?

 - What your business hours are- If they clog the toilet, perhaps they should be responsible for plunging it