In Maryland, you can install a mooring ball just about anywhere you wish, no permit required. Never checked into any other states about this, but I did check Florida's DFW site to see if they had a special permit for installing a private mooring ball. I couldn't find anything on this at all on the site.
I suspect that Florida, like some other greedy states, will likely prohibit the installation of a private mooring ball, whether or not you live aboard. Just a guess, though. Hey, Florida has some pretty high priced mooring fields in the keys that they keep filled with live aboards. But they really frown on anchoring in the same area for more than a couple weeks.
Gary