I would educate my tenants how to keep it from happening again and instruct them how to clear the drain. 

However, be sure to check with your bank for wiring instructions ahead of time so you are prepared.

Just search for that term, get plugged into local real estate groups in your area, and seek out training or an instructor on that subject.  

@David Beard is correct I believe based on this Forbes article and my reading of the code and instructions. 

I personally would not trust or want to do business with someone that didn't respect my "off limits" instructions.  

Immediately after closing, you or your property manager should have contacted the tenants and given them new contact number and rent payment instructions. 

I signed my closing docs Thursday and instructed the mobile notary to pick up flowers and take them to her hospital room when she is supposed to sign Friday(next day) BAD NEWS!

Outbuildings didn't have to be touched beyond basic clean out.I agree with others who have stated that plumbing and electrical can get you, but it's so worth working with a jack of all trades general contractor who knows her/his stuff and you know codes so you can give very specific direction and have them get the job done without having to use a full-fledged plumber.The following has nothing to do with your question about biggest expenses, but may save you big dollars in the long run:We were given some tips that have paid off: vacuum out your HVAC system to the best of your ability prior to inspection (inspectors see dirt or dust and they give you poor marks and tell potential buyers that a professional needs to be brought in to clean out the system); run Draino through your tub/shower drains (if you're leaving existing tub/shower in tact) prior to listing and test the drains to make sure there is good flow (we might or might not have used the tubs to clean paintbrushes, which resulted in REALLY slow drains); If you have a hand dug or shallow well, run bleach through it (lots of instructions online as to how to get bacteria out of the system when a hand dug well is involved) and flush the bleach immediately prior to inspection.I hope some of this helps. 

And how BP instructs people to navigate, evaluate, and manage rental properties is not sufficient for this post-rate hike '22 era.

Per IRS instructions on how to depreciate property:"A dwelling unit is a house or apartment used to provide living accommodations in a building or structure.