This was a fish tank that got moved in and woops, the tank sprang a leak in the move. 

If the market tanks, you hold onto it and keep collecting rent.

I then cut down enough trees (make sure you don't have a timber clause) to pay for a well and gravel road, then a year later or so, had saved enough for a septic tank and electrical. 

How much money are you saving on trying to repair the hot water tank as opposed to replacing it?

Prices aren't tanking yet, but I sincerely believe they will.  

After a few minutes I still hear the tank hissing. 

I have a whole pond's worth of tropical aquatic plants in my basement right now (in heated tanks of water even), and humidity hasn't been an issue.

Erik,Here are some things to lookout for from an Insurance perspective:1.Any in-ground tanks (active or inactive)2.Any Knob & Tube or Aluminum Wiring3.If built before 1978, does the building have Lead Safe certifications4.Any wood stoves or secondary heating units.

I won't invest in flood plains or areas with septic tanks or well water.

I had a cousin back in the 90's doing the borrow on one property to buy another and so on, and he had a number of properties and when the economy started to tank, all it took was for him to have trouble with one property and they all fell like dominoes, one after the other.