How much flood risk does Jefferson County actually carry?
Jefferson County lands at the 64.4th percentile of FEMA's National Risk Index for flooding, "Relatively Moderate" territory — a middling flood hazard by national standards — with the hazard driven by coastal storm surge rather than inland rivers — FEMA's model puts a surge event here at about 3.4 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 Jefferson 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, 17.1% of them do — 108 active policies against 631 structures FEMA counts in that zone, leaving a real compliance gap. Across all residential structures in Jefferson County, not just the ones FEMA mandates, 1% carry an NFIP policy — most flood damage nationally happens outside the mapped high-risk zone, so that broader number matters too.
Jefferson County against the rest of the country
Jefferson County sits at rank 1169 of 3144 counties on FEMA's flood hazard scale (1 is worst) and rank 1342 of 3144 by population (1 is biggest). Jefferson County, Washington is home to about 33,944 people across 1,803.728 square miles of land.
What to do next if you own or are buying in Jefferson County
FEMA counts 19,139 residential structures in Jefferson County overall, 193 of them carrying some form of NFIP coverage — but a lender or insurer cares about one parcel, not that county total.
More on how this number was built
The methodology guide shows exactly which FEMA and Census tables feed Jefferson County's numbers. Because storm surge plays a real role here, the guide to coastal vs. inland flood hazard is worth reading alongside this page.