“Don’t these people have faucets in their house?”
I’ll break it down for you. FL is low elevation and the whole state is on top of an aquafer. During hurricanes the storm surge and heavy rain usually contaminates ground water. I.e. saltwater, rainwater, runoff and sewage flood into the aquafer. This usually overwhelms municipal water filtration capabilities resulting in ‘boil water’ warnings. No one wants to drink cooked sewage so... bottled water.
So why not just save some water from the faucet BEFORE the storm comes?