The tax records of course will have them, but you have to kind of learn what the building classification codes are to figure out how to search them, which I could see being a hassle as you move to different areas.

@Joe SchaakI'd echo Joe here, if you don't understand St Paul, category 2 or 3 classifications on empty properties, you shouldn't be offering to buy them. 

Our land zoning classification is "O-S" Open Space.

The differences may have an effect on their classification in regards to qualifications for a mortgage and also on whether they are on a private lot or in a land lease community.

I'm new to BP and REI in general, but I've noticed several posts mentioning class B and D areas, etc. How are these measured?

I suggest that you pursue Quickbooks Plus; the Plus product comes with Class Tracking which makes this classification process that you previously did on Excel much less tedious and will unlock a lot of useful metrics as you pick up more properties.

I  just keep them in place .. much cheaper and talk about work having to find another tenant is much more work than just milking them along.the discount for early pay won't do much with a 600 dollar tenant either.. they simply have no money  that cant pay what they don't have.. its like folks think these folks have savings accounts and are doing it on purpose.. one is social  IE its simply not their priorities in their lives like it is in yours.thats my take on C class.... if you don't like whats currently happening .. then sell and buy nicer property .my A class everyone is on ACH  never a worry.. my C class over the years is exactly as described.

Window wells shall be designed for proper drainage by connecting to the building’s foundation drainage system required by Section R405.1 or by an approved alternative method.Exception: A drainage system for window wells is not required when the foundation is on well-drained soil or sand-gravel mixture soils according to the United Soil Classification System, Group I Soils, as detailed in Table R405.1.R310.3 Bulkhead enclosures.

You really should look at the tax card and determine the property classifications.

Window wells shall be designed for proper drainage by connecting to the building’s foundation drainage system required by Section R405.1 or by an approved alternative method.Exception: A drainage system for window wells is not required when the foundation is on well-drained soil or sand-gravel mixture soils according to the United Soil Classification System, Group I Soils, as detailed in Table R405.1.R310.3 Bulkhead enclosures.