Arlington County, VA flood risk explained
Flood hazard in Arlington County sits at the 73.8th national percentile, a middling flood hazard by national standards; driven by inland rivers and flash flooding rather than the coast — FEMA's model puts a flood event here at about 1.3 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.
Arlington County's flood-insurance compliance gap
FEMA's own figures for Arlington County report more NFIP policies in the mapped flood zone than FEMA's own count of residential structures there, which produces a compliance rate over 100% — a data problem on FEMA's side, not evidence that everyone here is over-insured. See the data quality guide for how widespread this is. Looking beyond the mandated zone, 1.9% of all residential structures in Arlington County carry flood coverage voluntarily or otherwise — relevant because most NFIP claims nationally come from outside the mapped SFHA.
Where Arlington County ranks
Among the 3144 US counties FEMA scores for flood hazard, Arlington County ranks 860 — 1 being the highest hazard nationally — and 302 by population among all 3144 counties covered here, where 1 is the largest. About 239,807 people live in Arlington County, Virginia, spread over 25.997 square miles.
Checking a specific address in Arlington County
FEMA counts 37,690 residential structures in Arlington County overall, 716 of them carrying some form of NFIP coverage — but a lender or insurer cares about one parcel, not that county total.
Where Arlington County's figures come from
Every figure on this page traces to a named FEMA dataset, documented in the methodology guide. Arlington 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.