Another time, the toilet got replaced & in so doing, the workers damaged the surrounding floor tiles and were not able to find matching tiles.

She would be squatting your house. 

This has the threefold benefits of: keeping the house clean, keeping an eye on any damages, and charging higher rents to cover the cleaning costs.I also recommend having the cleaning service stock the house with toilet paper, paper towels, and other general cleaning supplies since those are the things RBR tenants tend to argue/complain about. 

Water company will tell you if meter is/hass run constantly for x number of days. they should be able to tell you water usage compared to history for that building and compared to neighbors (make sure it’s same number of units.)In some areas they will send a team out to replace faucets, toilet valves and such to save water. 

(Allstate has done this twice for me against 2 different toilet supply line manufacturers.).

Also, when your place is vacant, you need to notify your insurance carrier and pay much more for insurance, about $100.00 a month (if you want coverage during being vacant), due to possible break ins to steal all your copper and they won't turn off the water when doing so, or squat and do drugs in your place etc... 

The toilet was full of human waste and wouldn't flush.

The only reason is they adding separate metering or the costs went higher and they do not want to disclose that fact.Any hidden cost will lower the NOI and make the offer price worse so the sellers like to hide as much as possible.If they hide 10 things and you find 5 then they still have a shot at a higher price.Get the utility numbers from the companies to see by how much they have increased,stayed,flat or decreased over the years.If water usage is high look for leaks at the line going to the street and check the toilets and plumbing for problems.You would need to find out the historical numbers year by year for the property as well as turnover rate.Time lines for eviction in your area to get them out and re-rent.Is your rent under market,competitive, or high for the market for your property you want to buy??

If the tub and toilet are still good damaging the piping and connections in that room will blow your rehab budget.

Dont call me when you flush your toy truck down the toilet.