Make sure that the City has authority to make rules on use of the lake. In many states, the State is the only entity legally authorized to control use of navigable waters, the water that lies above the land. Developers get around this issue by owning all land around a body of water and putting in rules for the land owners that they must follow. In many states, if you can get legal access to a body of water without trespassing, you can use it as long as you comply with State law. Keep in mind every state is different, so check where you are located.