Find out if each unit is individually metered and for what.5.

What kind of meters were used?

Water is not sub-metered and costs $450/month by owner.

If the tenant the turns it on themselves, the water meter is removed within 24 hours.And then the landlord gets a citation from the local council as you must have water and trash to a property?

I also read somewhere that there may be some monthly fee to get someone to go out to the property to read and reset the meter.

Each home is individually metered electric and water.

We also provide water meter keys with every property so a tenant could shut off the water at the street in an emergency, probably faster than even the water department could get there. 

There are so many other factors to consider (the market, size of the property, master or individually metered, etc), if you do use a 50% rule you may be hurting yourself when analyzing (good or bad). 

Would you especially recommend subdividing a larger property (a house) into studio apts. if the water and electric were still on a single meter? 

Do you know how to check the leak detector on the water meter?