How much flood risk does Washington County actually carry?
Washington County lands at the 71.1th percentile of FEMA's National Risk Index for flooding, "Relatively Low" territory — below the national norm for flood hazard — with the hazard driven by inland rivers and flash flooding rather than the coast — FEMA's model puts a flood event here at about 1.1 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 519 homes FEMA counts inside Washington County's mapped flood zone, 92 carry the flood policy federal law requires there — 17.7% compliance, short of full coverage. Across all residential structures in Washington County, not just the ones FEMA mandates, 0.4% carry an NFIP policy — most flood damage nationally happens outside the mapped high-risk zone, so that broader number matters too.
Washington County against the rest of the country
Washington County sits at rank 946 of 3144 counties on FEMA's flood hazard scale (1 is worst) and rank 480 of 3144 by population (1 is biggest). About 139,642 people live in Washington County, Tennessee, spread over 326.548 square miles.
What to do next if you own or are buying in Washington County
Across all of Washington County's 49,300 residential structures, 204 carry an NFIP policy today — a county-wide count that still can't tell you one address's own mapped zone.
More on how this number was built
The methodology guide shows exactly which FEMA and Census tables feed Washington County's numbers. The guide to what the Special Flood Hazard Area actually means explains why the mandatory-insurance rule exists and who it applies to.