Loudoun County, VA: flood risk, in FEMA's own numbers
On FEMA's National Risk Index, Loudoun County scores at the 83.9th percentile for flood hazard, rated "Relatively Moderate" — a middling flood hazard by national standards. 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 3 times a year. This describes the county, not any one street — FEMA only publishes exact parcel zones through a live map service.
Mandatory flood insurance compliance in Loudoun County
91.4% of the homes FEMA requires to carry flood insurance in Loudoun County — those inside the mapped Special Flood Hazard Area — actually have a policy in force: 64 policies against 70 mandated structures. Looking beyond the mandated zone, 1% of all residential structures in Loudoun County carry flood coverage voluntarily or otherwise — relevant because most NFIP claims nationally come from outside the mapped SFHA.
Loudoun County against the rest of the country
Among the 3144 US counties FEMA scores for flood hazard, Loudoun County ranks 529 — 1 being the highest hazard nationally — and 168 by population among all 3144 counties covered here, where 1 is the largest. Loudoun County, Virginia is home to about 443,380 people across 515.746 square miles of land.
What to do next if you own or are buying in Loudoun County
FEMA counts 57,388 residential structures in Loudoun County overall, 544 of them carrying some form of NFIP coverage — but a lender or insurer cares about one parcel, not that county total.
Where Loudoun County's figures come from
Every figure on this page traces to a named FEMA dataset, documented in the methodology guide. If you're unsure why any of this insurance requirement exists at all, the SFHA explainer covers it from first principles.