The biggest issue with lake water is a type of amoeba called Naegleria fowleri. This amoeba can exist in pretty much any body of fresh water if the conditions are right and the conditions in the summer in central Florida are ideal for it. This amoeba will enter through the nasal membranes and will cause an almost always fatal brain disease with flu like symptoms called Primary Amoebic Meningoencephalitis. Infections are quite rare as conditions pretty much have to be perfect, and I don't recall one ever occurring at WDW, but Disney wisely followed suit with nearly ever other fresh water lake in the state of Florida and closed their door to swimmers.Yeah Yoda I brought up the water thing b/c for some reason I remember reading a article my local newspaper after it was closed, I think the health dept might of been involded as well but don't quote me on it...