I am working on a CS project and each tenant space is metered separately with a single meter.

The plumbing in the common areas (hot and cold water) and irrigation make-up (in addition to reclaimed storm water) is on the house main meter.  I believe to meet the credit requirements that just the irrigation make-up needs to be sub-metered and the Indoor plumbing fixtures and fittings will be determined by deducting the irrigation make-up from the main house meter.  Can someone please confirm or point out any issues in my logic.  I further believe that metering the reclaimed water from the storm water capture, would be a interesting data but is not required and would be a 3rd subsystem.