Currently, there's only one water meter for the entire duplex, and historically, I've been responsible for paying the water bills every month.However, I believe it's time to transition to a system where the water bill is split between the two tenants.

To me this actually makes much more sense than the current system, people just don’t like change lol, basically the buyer & thier agent negotiate a fair fee and that fee is no longer being “hidden”. the agent than negotiate’s a concession with the sellers agent, that’s literally it, it’s a totally logical system that makes much more sense then the current one, and I think people (mainly agents who are afraid as soon as the seller realizes they are getting 3%, that they might not be worth it) are just making way to big of a deal of it.

I would definitely connect with a good agent that sources a ton of off-market deals and has the right systems to help you understand the market. 

Systems and SOPs are KEY!

Key management is simple....all of your properties should be keyed to a master key system. 

No formula can be accurate across the board because even “cookie cutter” properties next store to each other differ as to view, location to the street, topography of the land, lot size, physical condition of the property, past remodeling, quality of the mechanical systems, sunlight, utility bills, past use, etc.  

Quote from @Scott Mac: Well guys, I agree with all of you.Although I do see some nuances.There are bread and butter deals, and there is shark food.Shark food can put you in a new Mercedes with a Burmeister sound system.

It could mostly be connected to costly upgrades to the system where the finance won't go.

A little context: the building is structurally sound and they have done major updates such as septic, generator, and sprinkler system, and all mechanicals are recently inspected and tagged.

This includes some major items like below upgrading septic to elgin septic system 20kupgrading electric to new cod 20ktree cutting trimming 10ktrench/French drain 10khvac replacement repair 10knew plumbing 10kcrawlspace repairs 10kappliances replacement 5kdoors replacement 5kmold repairs 3kroof repairs 3kother repairs It is in good location.