Flood hazard zone

A flood hazard zone is FEMA's designation of the flood risk applying to a location, and in this catalog it exists in two forms. As geometry, it is a polygon layer set in the National Flood Hazard Layer served through FEMA's ArcGIS Hub site with REST, GeoJSON, Shapefile and KML endpoints; NFHL digital data covers over 90% of the U.S. population and feature queries return up to 2,000 records each. As an attribute, it rides on insurance records: NFIP Redacted Policies v2 lists "flood zones" among the fields on 73,601,802 policy transactions effective from 2009-01-01, while NFIP Redacted Claims v2 carries "flood zone" on its 2,721,780 claim records with loss dates from 1970-08-31. Both OpenFEMA files were frozen as of 2026-06-01 during v2 deprecation.

Flood zone is a core NFIP rating and underwriting attribute sitting beside coverage amounts, premiums, fees and deductibles, so sloppy handling of it prices risk wrong.

• A zone string without its vintage is unrateable. Zone boundaries get revised; pairing a today-date premium file with an old zone polygon misstates exposure.
• The two OpenFEMA products are frozen mid-deprecation. Policies v2 and Claims v2 stopped at 2026-06-01 during v2 deprecation, so any pipeline built on them inherits that cutoff unless a successor release replaces it.
• Geography is deliberately coarse. Locations arrive as state, ZIP, county FIPS, census tract, block group and rounded lat/long - parcel-level joins to buildings are not supported by design.

1. Confirm which representation you need. Polygon geometry comes from the NFHL "Flood Hazard Zones" layer set on FEMA's ArcGIS Hub; the rating field comes from NFIP policy and claim records.

1. Check record depth and cutoff dates. Policies v2: 73,601,802 transactions from 2009-01-01, frozen 2026-06-01. Claims v2: 2,721,780 records with loss dates from 1970-08-31.

1. Respect the OpenFEMA usage terms. Both datasets restrict use to statistical research or reporting-record purposes and prohibit reidentification of individuals.

1. Plan around the 2,000-record query cap. NFHL feature services return up to 2,000 records per query, so bulk zone extraction needs paginated or file-download routes (GeoJSON, Shapefile, KML).

1. Note the license posture. NFHL layers are free under a FEMA disclaimer with no accuracy guarantee; some contributed hub layers carry commercial delivery terms 4.0 or commercial delivery terms-SA 4.0 terms.

Entries that sit next to Flood hazard zone in this glossary:

• national-flood-hazard-layer
• nfip-redacted-claims
• nfip-redacted-policies