Water Submetersing Question

Hello all,

I am looking at a deal and wanted to get some input about water submetering. What is the average % drop when you guys have done submetering(City water and sewer park)? This might sound like a dumb question, but I am guessing it will probably not go down to zero if you have a manager in there and you are giving them free lot rent with utilities.

So what are you guys seeing?