Grayson County, TX flood risk explained
Flood hazard in Grayson County sits at the 79.5th 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 2.2 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
16.9% of the homes FEMA requires to carry flood insurance in Grayson County — those inside the mapped Special Flood Hazard Area — actually have a policy in force: 153 policies against 905 mandated structures, which means a meaningful share of legally-required coverage simply isn't there. Looking beyond the mandated zone, 0.5% of all residential structures in Grayson County carry flood coverage voluntarily or otherwise — relevant because most NFIP claims nationally come from outside the mapped SFHA.
How Grayson County compares nationally
Among the 3144 US counties FEMA scores for flood hazard, Grayson County ranks 672 — 1 being the highest hazard nationally — and 463 by population among all 3144 counties covered here, where 1 is the largest. About 150,532 people live in Grayson County, Texas, spread over 932.832 square miles.
Checking a specific address in Grayson County
Across all of Grayson County's 57,645 residential structures, 281 carry an NFIP policy today — a county-wide count that still can't tell you one address's own mapped zone.
Where Grayson 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.