Kiawah is a barrier island with marsh on one side and ocean on the other, and storm water has to be managed rather than assumed away.
What actually needs protecting
Because homes are raised, tidal water generally passes underneath rather than into living space. What still floods is ground-level storage, garages, equipment enclosures and lower-lying sections of a property — which on these homes often contain expensive equipment rather than just boxes.
Salt water is harder on pumps
A pump handling brackish flood water corrodes faster than one dealing with rainwater. Specifying properly for that decides whether it still works next season.
Backup power matters more in an empty house
A storm takes the power out and, if nobody is in residence, nobody resets anything. A battery backup, and ideally a system that alerts someone, is what makes a pump useful on a property you are not living in.
Test before hurricane season
Pour a bucket into the pit and confirm it starts, clears and stops cleanly. If your home is managed for you, this is worth adding to their seasonal checklist.