@David Cook this is why we’ve started using water based polyurethane on our hard wood floors.

8 - What type of natural drainage will there be on the site/9 - What type of water supply will you be using?

The first farmer tries to plant, water, and harvest everything himself.

When it was clear water was running from the unit.

Appears the guests may have left the faucet "on" when the pipes were frozen and when no water came out, forgot to turn it "off".What may have caused the overflow of the sink is maybe the drain lines were also frozen?

It costs the same thing to fix a hot water heater or remodel a bathroom on a $200K house as a $100K house.   

If they can't do that, keep shopping.This may require digging up the foundation, sealing it from the outside, and installing a french drain to keep water away from the walls.

Water overflowing the sink, seems more plausible than some missing caulk.  

Start with maintenance notes that you may regularly reference, such as air filter size, water shut-off location, etc.

Plus very few of these groups smoke or drink so that's other problems eliminated.