If they are having similar usage then it's easier, but you still may have disagreements.

@Jay Hinrichs $ @Paul Passafiume yes, in my area part of the planning clearance is a "fire flow form" which assesses the nearest hydrant, density of usage, etc.

The existing rental agreement specifies that the tenant is responsible for all their own utility usage bills (I pay water for the building, as is typical).

We got notes from investors and so did my brother back then, we ignored them all as it's inappropriate in these situations to tell the owner "you'll be dead soon, and I just can't wait for my money".

And for water/sewer, you can either install sub-meters and charge for usage (better way, but more expensive) or just come up with a flat fee and pass it along to tenants.That's my two cents -- hope it helps!

Amount of depreciation is also dependent on your % business usage as well

@Skye Anderson, Most of the electric meters today are smart meters, they are controlled by a cell signal to report usage, turned off and on by the power company.

Do not under any circumstances meet or go to that place.  100% these are the type of people that will say you did something inappropriate (assault, unlawful entry whatever) just to get you on your heels2. 

Also water heater life is controlled by maintenance, usage, thermocouple, piezo quality. 

Inappropriate?