DuPage County, IL: flood risk, in FEMA's own numbers
On FEMA's National Risk Index, DuPage County scores at the 98th percentile for flood hazard, rated "Relatively High" — well above the national norm for flood hazard. 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 2.8 times a year. County-wide, not parcel-specific: FEMA's real flood-zone map is queried live, never shipped as a download.
Who actually carries the flood insurance FEMA requires
40.8% of the homes FEMA requires to carry flood insurance in DuPage County — those inside the mapped Special Flood Hazard Area — actually have a policy in force: 1,014 policies against 2,485 mandated structures, which means a meaningful share of legally-required coverage simply isn't there. Looking beyond the mandated zone, 0.6% of all residential structures in DuPage County carry flood coverage voluntarily or otherwise — relevant because most NFIP claims nationally come from outside the mapped SFHA.
How DuPage County compares nationally
Among the 3144 US counties FEMA scores for flood hazard, DuPage County ranks 71 — 1 being the highest hazard nationally — and 61 by population among all 3144 counties covered here, where 1 is the largest. DuPage County, Illinois is home to about 937,142 people across 327.892 square miles of land.
Your street may differ from DuPage County's average
Across all of DuPage County's 297,865 residential structures, 1,772 carry an NFIP policy today — a county-wide count that still can't tell you one address's own mapped zone.
Where DuPage 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.