Only 390 counties in the US hold about 90% of the National Flood Insurance Program (NFIP) flood insurance policies.
To put that in perspective, there are about 3,144 county and county equivalent areas in the US. Therefore, about 12% of the counties hold about 90% of the flood insurance policies. And there are about 169 million people living in those counties, which is 54% of the US population.
About 700 counties hold 95% of the policies and, here is where I think it gets interesting, about 1600 counties hold 99% of the policies. That’s about half of all counties in the US. Those 1600 counties have about 267 million people living in them, which is 84% of the US population.
Further, there seems to be less than 100 counties (3% of all US counties) that have no flood insurance policies. So if you are saying “yeah, that may be a lot of people at risk, but it can’t happen to me”, the numbers would say otherwise.
What’s my point with all the numbers? It’s that you are probably going to be affected by a flood in your lifetime. You might be affected personally or through a friend or relative. Or your county might be affected and maybe you are hoping the water and debris won't hit your house while you gather your possessions and flee. Or maybe the flood map was wrong.
The lines on the FEMA floodplain maps are a baseline for mandatory flood insurance purchase, but please don’t let that be your risk decision. Protection is not as simple as "in or out" of the floodplain.
Talk to a professional and discuss your options. You could be just one foot outside the mandatory purchase line and Mother Nature doesn’t read maps or abide by government regulations. If you are not in the mandatory-purchase flood zone, you can still buy flood insurance and the rates are much lower than you think.