How much flood risk does Washington County actually carry?
Washington County lands at the 48.4th 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 1.7 times a year. 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
Homes with a federally backed mortgage inside Washington County's mapped high-risk flood zone (the Special Flood Hazard Area, or SFHA) are legally required to carry an NFIP flood policy. In practice, 25.6% of them do — 76 active policies against 297 structures FEMA counts in that zone, leaving a real compliance gap. Across all residential structures in Washington County, not just the ones FEMA mandates, 0.9% carry an NFIP policy — most flood damage nationally happens outside the mapped high-risk zone, so that broader number matters too.
How Washington County compares nationally
Washington County sits at rank 1685 of 3144 counties on FEMA's flood hazard scale (1 is worst) and rank 1694 of 3144 by population (1 is biggest). About 22,631 people live in Washington County, Iowa, spread over 568.828 square miles.
Your street may differ from Washington County's average
84 of Washington County's 9,766 residential structures carry flood coverage of some kind, per FEMA's latest count — useful context, not a substitute for checking one parcel.
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.