Lake Purdy is controlled by the Birmingham Waterworks. They only allow boats rented from them "to stop invasive species from being introduced into the water". Which means no swimming, skiing, etc. They do allow people to bring their own motors, and their own bait which seems to contradicts the stated purpose of only allowing rental boats. If going for fishing and you dont mind doing it from the bank or rental boat, Lake Purdy is great. For any other purpose it's unfortunately off limits. It really is a beautiful place.