The sole purpose of designating a animal as ESA is to get around regulations that prevent pets to be taken into certain areas.

I'm trying to prevent a problem before it happens, and was looking for a more technical answer.Thanks!

I usually break it down into 5 pillars of asset protection (though in reality there are many more...)1st pillar is avoiding unnecessary and risky activities (don't drink and drive, insurance generally won’t cover your poor decisions) and take good care of your investments - these simple steps will help you prevent lawsuits before they even occur.2nd pillar is a good insurance policy as that cover the majority of your exposure.

Never any carpets, Cabinets: Plain Project Source cabinets and stain myself if I absolutely have to replace which is very rare.

And is there a way to prevent it, or to see if the tenant was a problem prior to the purchase of the property? 

I'm considering adding them to even my cheapest rentals because I believe that they are likely to prevent large drain clogs and they are such a nice amenity.

@Kyle Gilbert I agree with the group here...in difficult situations or with combative tenants it may make sense to issue LOI or even a contract with a contingency...so, get in the units you can, get the property secured with a LOI/contract, and then leverage the seller to see every inch of the property before you can remove the contingency and close the deal...It's amazing the lengths some tenants will go to in order to prevent a deal from happening out of fear of the unknown...it's good to have leverage on the seller to assist with getting in the units if they want to sell the property.

It may even prevent them from feeling entitled, as many kids now days seem to feel.

You'll probably also need a back-flow preventer installed.All that being said, If you do replumb interior, pull permits, use PEX and put that in your house description when you sell. 

While showing the place I noticed some coloring on the walls and what I thought were marker stains on the carpet.