If they stay longer than a year, this will really pay off.Laundry Mat: If you own a mid/large MF property then consider adding coined machines. 

If it's the latter, without too much information it sure sounds like your unit caused the water damage via overflow of the sink basin and/or a leaking S-trap underneath your sink when your drained the basin. 

•⁠Sometimes I come across something called an S-trap, and it’s bad.

You are right Mat, we don't know he has no license which is our fault.

Mat?

Do you have room mats or are you able to rent a room out for some extra income?

And attorneys to sue you over negligence.I find that slumlords are not profitable operators, but landlords who are financially strapped or have lost interest in running their business.   

@Mat Kik great question!

@Christian Hansen and @Dennis M., At this point there really isn't much more that I can do beyond what I have done.

Getting started in real estate, my funds are a bit strapped with fees, renewals, memberships, etc but sales are not as expedient.