There is also a system that is basically a holding tank that sits behind the wall for a basement bath that collects waste and water and pumps it to the stack without going under concrete but i feel like its one more thing to break down and the initial cost of a toilet to work with that setup may be more expensive. you could also consider a half bath as you would need less room.

Having never owned fish tanks or birds of any kind, I really don't if its even a thing to worry about possible damage or lasting smells. 

I know that the market is a little unrealistic as far as most home prices but I figured of the market tanks which no one can predict that I can still hold on to the property and the market will eventually come back up.

If the law changes so that it says you can't evict tenants and the economy tanks so that you can't rent your unit for a long period of time - who can weather that? 

Fish tanks, computer equipment, lighting, heating pads, portable air conditioner, electric blankets, power tools, just on and on. 

If you are only getting desperate-looking people who are trying their hard luck story at every advertised vacancy and the local market is not totally tanked,  you may be asking a bit too much.Good luck.

@Brandon Fuhrman it’s very hard and speculative to control appreciation as anything can happen and a property value soars 20% or tanks 10%.

One thing you can do, though, is limit your property on number of occupants, if you have a good reason - like your septic tank can only handle so many people, that kind of thing.

They may lose money but they can always walk away and invest in another deal that comes down the road if this one tanks. 

I wanted to share the solution that I put in place to manage our properties while we're traveling, and I'd love to hear some perspective about its strengths, weaknesses, or alternatives.This solution was really put to the test and passed when I was unreachable for days in the bottom of Palo Duro Canyon and a hot water tank popped off in one of the houses.