I am sure it will depend on the local bylaws, I am fairly sure that as long as it is not roped off as a 'no boat' area you should be fine. I know its common sense, but if you don't go tearing in there like a maniac I am sure no one will mind. Not sure with ajet ski, but with my jet boat I always switch off the engine around 10 feet from the shore and float in as not to suck anything up in the shallows.