At the bare minimum, if roofs leak, leaky faucets, water damage and dry rot on floors, filthy carpets, worn out paint, etc. do what is expected as a property owner maintaining your investment. 

The person who's paycheck to paycheck thinks you're loaded, but they also have the latest Iphone while I'm walking around with a 3 year old android that cost 1/4 of the Iphone in the first place.

If I’m going to put something in my wall that could potentially leak and destroy my house, I’m going to spend a little more.

In a multi-unit, none of the tenants might be able to access the main shut-off, so that's the landlord's (or property manager's) job.If it is a roof leaking, then there is no water valve to shut-off - and you might be inclined as David suggested, to do what is necessary to preserve things and minimize damage.Of course, that all assumes that you were receptive to getting a call at odd hours ...

But no leaking and no comments on rusting in (the inspector opened the furnace and looked), I wouldn’t worry too much.

When you put a screw driver in their hand, have them change a door knob, have them fix a leak, rehab a house, manage a property, build a house...

Like what I read in the legal case with the leaking gas pipe?

Think of the Cyber Truck from Tesla or every new version of the I phone.

If installed properly there shouldn't be any higher risk of water leak than any other shower. 

If I am reading your numbers correctly you are saying that you are cash flowing $876 annually for a $53,000 investment plus your time, risks and unknown expenses e.g. loss due to vacancy, cleaning after a tenant destroys the property, painting, carpets, utilities when it is vacant, new water heater, furnace, air conditioner, leak in the roof, broken or leaking drain pipe, sewer, water pipe, gas leak, or replace or repair leaking faucets, broken screens, repairing locks, trash removal, city sewer use fees and a lot more.