Boone County, IA: flood risk, in FEMA's own numbers
On FEMA's National Risk Index, Boone County scores at the 28.8th percentile for flood hazard, rated "Very Low" — among the lowest flood hazard in the country. The hazard here is driven by inland rivers and flash flooding rather than the coast — FEMA's model puts a flood event here at about 1.7 times a year. That's a county-wide figure, not a per-address one — FEMA's parcel maps are a live lookup, not a bulk file.
Who actually carries the flood insurance FEMA requires
Out of 306 homes FEMA counts inside Boone County's mapped flood zone, 20 carry the flood policy federal law requires there — 6.5% compliance, short of full coverage. Looking beyond the mandated zone, 0.2% of all residential structures in Boone County carry flood coverage voluntarily or otherwise — relevant because most NFIP claims nationally come from outside the mapped SFHA.
How Boone County compares nationally
Among the 3144 US counties FEMA scores for flood hazard, Boone County ranks 2290 — 1 being the highest hazard nationally — and 1549 by population among all 3144 counties covered here, where 1 is the largest. Boone County, Iowa is home to about 26,729 people across 570.461 square miles of land.
What to do next if you own or are buying in Boone County
Across all of Boone County's 11,459 residential structures, 25 carry an NFIP policy today — a county-wide count that still can't tell you one address's own mapped zone.
Where Boone County's figures come from
Every figure on this page traces to a named FEMA dataset, documented in the methodology guide. If you're unsure why any of this insurance requirement exists at all, the SFHA explainer covers it from first principles.