It is not that hard to add city water, but be aware of the mains pressure. Your boat system is designed for pressures in the 30 PSI range. I have seen city water systems as high as 80 PSI. There may also be city codes requiring a back flush preventer.
The biggest risk is that of flooding the boat--and some advise turning the water off at the dock each time you leave the boat for any period of time.
If your 2007 is like mine, you would put a "Y" valve at the outflow from the water pump. Put the hook up for city water in the cockpit on the aft port side (I have a fresh water wash down fitting there). You would have the outlet of the "y" to the water system, and one input from the pump. the other from city water mains.