Just starting out and testing waters for BRRR in Chicagoland area.Any advice or suggestions regarding this?

For example we replaced a water heater recently.

Sounds like you stopped water which is most important.

Utilities are OFTEN overlooked so reach out to power, telecom, gas (or go all electric), water, and sewer to make sure you understand what it would take to get separately metered services from the primary house.

If the water bill is $100 a month, increase the price by 20% (or whatever you decide is fair) to compensate you for the time required to split and bill and to cover additional use when tenants squander the utility.

The property has 2 electric meters and one water meter.

It's wise to stick your toe in the water first and fail fast in a small way if you're going to fail, right Vanessa?

Each of the 5 warehouses on this campus will require updates (construction of offices/bathrooms, roof repairs, paint, siding repairs, new penetrations for doors, updates to electrical, insulation, and extension of water and sewer). 

Licensed with permits ~$4,000.Full replacement of all water supply lines and shutoffs from the interior water meter with PEX and an open basement.  1 kitchen 1 bath 1 laundry. 

I a factoring in the replacement of the AC unit and potentially the water heater, and the cosmetic thins (I would do myself) to get it to rentable standard.