I've heard of kids flushing toys down the toilet. 

They deploy it to get deals done knowing it comes back either in short term gains or as passive cashflow.For that new Investor just getting in, unless they're flush with cash, they have enough money for a deal and if you have one bullet right now as an investor it's tough to get things done because you have the costs of the deal plus you have holding costs, and you have first in money for a contractor. 

If the tenant/owner is not home, I will turn the water on full blast and flush toilets to see if there is any sewage issue.

I always give them a month or two if they are nice.. and are keeping the house in decent shape.. if you get hard nosed you can end up with a trashed house pretty quickly.. cement down the pipes etc.Now some others do it different .. they just start eviction process with no personal contact.. if its a tenant the eviction flush's that out and then the owner is evicted.. and you deal with what you have..

I'll second most of Nate G's wisdom above with one caveat,It is indeed better to let the qualified and often more prudent landlord "triage" maintenance and repair items and indeed the responsibility for maintaining the habitability of the property is squarely on the LL.BUT when a maintenance or repair item is needed to correct an issue caused by the tenant (like diapers flushed down the toilet, garbage disposal being run with a bottle in it, etc, this NEEDS to be assessed to the tenant. 

Just make sure the CC&R's will allow for what you are looking to do with it.I like condo's if the HOA is flush and not looking at assessments then the bulk of your Capex items are being paid out of your HOA dues and you don't have to worry about coordinating contractors.Best of luck!  

Perhaps that way they will take responsibility for water usage and noticing of leaking water or constantly flushing toilets.  

That should flush him out!

Notes: -Carpeting will be replaced with LVP throughout -Wood paneling will either be removed or painted over (filling in gaps, sanding, etc) -Considering closing off the sunken in space to make the wall flush? 

A good inspection should catch big ticket problems (like foundation and roof issues), but you won't catch some plumbing issues until tenants are actually flushing toilets.