I raised the rent to $800 because I was planning to transition the units to paying for their own heat so a lower rent amount was fair.

@John Su tenants typically take care of snow when occupied, but owner is responsible when vacant - and some cities write tickets if snow not removed with x hours.In colder climates you also have to worry about keeping heat on when vacant so pipes don't freeze.

A house can pass inspection but once someone is living there it's being put under daily stress (faucets turned on/off, heat/AC on an off, etc) so be prepared for repair costs 

I didn't like that it took half an hour to heat up, meaning I had to think of it in advance.

Windows are drafty etc and heating through out the house is very Inconsistent. 

I've backed out of deals due to roofs and ACs/Heating if I didn't like the inspection report info. 

Only these type of requests (water leak and no heat are urgent) and then you should text/call (your preference).

So I analyse each property individually, looking at major features like roof, heating, cooling, hot water, anything likely to break down really. 

Or is the landlord always responsible for the water bill and heat?

The heat is problematic.