How much flood risk does Twin Falls County actually carry?
Twin Falls County lands at the 51.1th percentile of FEMA's National Risk Index for flooding, "Relatively Low" territory — below 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 once every 3 years. This describes the county, not any one street — FEMA only publishes exact parcel zones through a live map service.
Who actually carries the flood insurance FEMA requires
20.5% of the homes FEMA requires to carry flood insurance in Twin Falls County — those inside the mapped Special Flood Hazard Area — actually have a policy in force: 54 policies against 263 mandated structures, which means a meaningful share of legally-required coverage simply isn't there. Across all residential structures in Twin Falls County, not just the ones FEMA mandates, 0.2% carry an NFIP policy — most flood damage nationally happens outside the mapped high-risk zone, so that broader number matters too.
Where Twin Falls County ranks
Twin Falls County sits at rank 1601 of 3144 counties on FEMA's flood hazard scale (1 is worst) and rank 643 of 3144 by population (1 is biggest). About 96,509 people live in Twin Falls County, Idaho, spread over 1,921.716 square miles.
Your street may differ from Twin Falls County's average
FEMA counts 32,422 residential structures in Twin Falls County overall, 67 of them carrying some form of NFIP coverage — but a lender or insurer cares about one parcel, not that county total.
More on how this number was built
The methodology guide shows exactly which FEMA and Census tables feed Twin Falls 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.