this is a perfect question for the building department. Now I happen to also use a rule of thumb. If I am near a body of water ( 100 feet ), I'm going to guess that it needs pilings automatically. it's error on the side of cautions.
This would be a good question for the City of Hollywood Building Department. Most homes which are close to the Intracoastal and the Beach areas most likely would require pilings and grade beam. Outside of that you are probably OK with just a dig and concrete. Hope this helps. Call me anytime at Hollywood Homes.