I can't answer about the Gulf, but I am oceanfront here in the Nags Head Kitty Hawk, NC coast. 80% of all homes here are in a flood zone and are required by the lender to have flood insurance, so it's very common here to have it. It's not all that expensive and it is all based on elevation above sea level. Higher is better and cheaper, this is the height of the ground, not the house on stilts (pilings). My house is about 200 ft from the ocean and is 1 lots back from it and I pay $430/yr for the max coverage of $250k. If you go back farther flood ins rates drop slowly and $250 is not uncommon. Those oceanfront homes can pay $2000 in some cases if the elevation is not high enough to reduce it. And again, FEMA flood only covers to a max of $250k. Those owners that must have flood to cover a million dollar home must go to Llyods of London, or some other private insurance co, and that can easily run $10-20k / year.