Williams County, OH: flood risk, in FEMA's own numbers
On FEMA's National Risk Index, Williams County scores at the 51.8th percentile for flood hazard, rated "Relatively Low" — below the national norm for flood hazard. 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 once every 5 years. This describes the county, not any one street — FEMA only publishes exact parcel zones through a live map service.
Who actually carries the flood insurance FEMA requires
FEMA hasn't published a residential structure count for Williams County's mapped flood zone, so a reliable mandatory-compliance percentage can't be computed here — see the data quality guide for why this gap exists for roughly a quarter of US counties. Looking beyond the mandated zone, 0.2% of all residential structures in Williams County carry flood coverage voluntarily or otherwise — relevant because most NFIP claims nationally come from outside the mapped SFHA.
Where Williams County ranks
Among the 3144 US counties FEMA scores for flood hazard, Williams County ranks 1581 — 1 being the highest hazard nationally — and 1282 by population among all 3144 counties covered here, where 1 is the largest. Williams County, Ohio covers 420.66 square miles and counts roughly 36,554 residents.
What to do next if you own or are buying in Williams County
Across all of Williams County's 16,828 residential structures, 40 carry an NFIP policy today — a county-wide count that still can't tell you one address's own mapped zone.
Where Williams County's figures come from
Every figure on this page traces to a named FEMA dataset, documented in the methodology guide. Williams County's compliance figure is one of the ones affected by FEMA's incomplete denominator data — the data quality guide explains what that means and how many counties it touches.