How much flood risk does Gwinnett County actually carry?
Gwinnett County lands at the 97.4th percentile of FEMA's National Risk Index for flooding, "Relatively High" territory — well above 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 1.2 times a year. County-wide, not parcel-specific: FEMA's real flood-zone map is queried live, never shipped as a download.
Mandatory flood insurance compliance in Gwinnett County
63.1% of the homes FEMA requires to carry flood insurance in Gwinnett County — those inside the mapped Special Flood Hazard Area — actually have a policy in force: 470 policies against 745 mandated structures, which means a meaningful share of legally-required coverage simply isn't there. Across all residential structures in Gwinnett County, not just the ones FEMA mandates, 0.4% carry an NFIP policy — most flood damage nationally happens outside the mapped high-risk zone, so that broader number matters too.
How Gwinnett County compares nationally
Gwinnett County sits at rank 91 of 3144 counties on FEMA's flood hazard scale (1 is worst) and rank 50 of 3144 by population (1 is biggest). Gwinnett County, Georgia covers 431.135 square miles and counts roughly 1,003,869 residents.
Checking a specific address in Gwinnett County
Across all of Gwinnett County's 259,496 residential structures, 989 carry an NFIP policy today — a county-wide count that still can't tell you one address's own mapped zone.
More on how this number was built
The methodology guide shows exactly which FEMA and Census tables feed Gwinnett 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.