How we calculate

All numbers come from FEMA's OpenFEMA program, which publishes redacted records of every National Flood Insurance Program (NFIP) policy and claim. We download the full files and summarise them by state, county and ZIP code.

Policies in force counts NFIP policies active on 5 September 2026. We use a date a few weeks before the newest records in FEMA's file, because the most recent weeks are still being loaded.

Average premium is the average total premium per policy record, before fees and surcharges.

Claims include every NFIP claim since 1978. Paid adds building, contents and increased-cost-of-compliance payments.

Flood zones use the policy's current FEMA flood zone, or the zone it was rated under when the current zone is not reported.

We only publish detailed pages for places with enough policies or claims to give meaningful numbers. Smaller places are still included in their state totals.

Private flood insurance is not part of FEMA's data, so the real number of insured buildings is higher.