Looking to split utilities for the first time

[Aaron Wolman]

I just purchased my first duplex (only SFHs in my portfolio so far) and it doesn't have the gas/water split. It cash flows without the utilities split but I am planning to hold onto for a long time so splitting the utilities seems to make sense. What steps should I do to start this? Is it worth bringing in my contractor first to see how difficult it would be or should I call the gas and water companies first? Any general advice would help.  A little more info, I am doing a full cosmetic rehab on one of the units and a lighter one on the other but I am assuming if I am going to split the utilities I should do that prior to any rehab. 
TYIA