Most of FL is less than 20 foot above sea level. If Sanford is having this problem, Deltona must be absolutely flooded. They let developers do stupid things there. Lots of houses and whole neighborhoods flood on a regular basis.
Even in Florida, sewer systems are local in nature. As for Sanford, it resides on the shore of Lake Monroe, a large body of water that is the head of navigation for the St. Johns river. Although Sanford has an elevation of some 35 feet or so above sea level, I have seen a hurricane swollen Lake Monroe overflow its banks to flood many of downtown Sanford’s streets. The current problem is the more frequent one of Florida’s tendency toward heavy thunderstorms.