Sub-Metering Water

So, I had this idea of trying to control costs some more by having separate water meters for each unit. I have separate electric but not separate heat which is killing me right now. So, sent emails to National Grid, who is my service provider for gas, and to DEP, which provides water. National Grid was pretty prompt and said individual separate meters can be installed once you get a licensed HVAC person to have separate boilers installed and properly piped. They will install a meter for each unit. DEP said that they provide only one meter per building. The owner can sub-meter with a licensed plumber and monitor usage that way and go from there. Some have used the RUBS system but since I have a commercial space, I could see this being an issue in the future. Anyone ever sub-meter for water? How was the process and was it worthwhile?