Think of it this way
If you go to an all you can eat buffet, you tend to load your plate up with as much food as possible, even if you aren't going to eat it all. This way, you get the most bang for your buck. The same thing happens when residents don't pay for their actual consumption. Showers and sinks seem to be left running longer and lights and TV's tend to stay on when no one is using them.
Contact Byram Labs to get started with your own submetering system and start improving costs and energy consumption at your property.