API reference: GET /api/v1/flood/zone

One endpoint. It takes an address or a point and returns the FEMA flood zone, SFHA flag, static base flood elevation and FIRM panel at that point.

GET https://api.floodzoneapi.com/api/v1/flood/zone

Authentication

Send your key as a bearer token: Authorization: Bearer fza_.... A ?key= query parameter also works, but URLs end up in logs, so prefer the header. Keys belong to your account and work only on this API. Create and revoke them on your account page; up to five at a time.

Parameters

Send exactly one of: address, or lat with lon.

Response fields

Every successful answer is HTTP 200 with Content-Type: application/json, including points FEMA has not mapped ("mapped": false). Within v1, fields may be added; existing fields are not renamed or removed.

queryobject

Echo of your input: {"address": ...} or {"lat": ..., "lon": ...}.

location.lat, location.lonnumber

The point looked up, to 6 decimal places.

location.geocoderstring or null

"census" (US Census Geocoder), "openstreetmap" (fallback, used only when its result has the same house number as your address) or null when you sent coordinates.

location.precisionstring

"address_range": interpolated along the street segment's address range (Census). "address_point": an OpenStreetMap building or address point. "input_coordinates": your lat and lon.

location.matched_addressstring or null

The address the geocoder matched. Compare it with what you sent.

location.candidatesinteger or null

How many matches the geocoder returned. We use the first; more than 1 means the address was ambiguous.

location.county, location.county_fips, location.statestring or null

County name, 5-digit county FIPS and 2-letter state code, when the geocoder supplies them (null for coordinate lookups).

flood_zone.mappedboolean

false when FEMA's digital map has no flood hazard area at the point. All other flood_zone fields are then null or empty.

flood_zone.zonestring or null

FEMA's FLD_ZONE, for example "AE", "X", "VE". See the zone table below.

flood_zone.subtypestring or null

FEMA's ZONE_SUBTY, for example "FLOODWAY" or "AREA OF MINIMAL FLOOD HAZARD".

flood_zone.descriptionstring or null

A one-line definition from the FIRM legend.

flood_zone.sfhaboolean or null

FEMA's SFHA_TF: in a Special Flood Hazard Area or not. null when unmapped or AREA NOT INCLUDED.

flood_zone.static_bfeobject or null

{elevation, unit, datum} from STATIC_BFE, LEN_UNIT and V_DATUM. null where FEMA stores -9999 (no single elevation for the zone). Datums vary (NGVD29, NAVD88 and others).

flood_zone.depthobject or null

{value, unit} for AO zones, from DEPTH; otherwise null.

flood_zone.dfirm_idstring or null

The digital FIRM database the zone polygon belongs to, for example "12086C". IDs ending in C are countywide.

flood_zone.polygon_idstring or null

FEMA's FLD_AR_ID for the polygon. Useful for spotting when the polygon at a point changes.

flood_zone.at_zone_boundaryboolean

true when the point touches polygons with different zones. We return the most hazardous: V zones, then other SFHA zones, then shaded X (0.2%, shallow or small-basin 1%, future conditions, levee-protected), then other X, then D.

flood_zone.other_zonesarray

The other zones at a boundary: [{zone, subtype, sfha}].

firm_panelobject or null

null when no FIRM panel covers the point.

firm_panel.panelstring

The FIRM panel number, for example "12086C0317L" (the final letter is the panel's revision suffix).

firm_panel.effective_datestring or null

The panel's effective date, YYYY-MM-DD. null where FEMA's record holds a placeholder such as 9999-09-09.

firm_panel.panel_type, firm_panel.dfirm_idstring

FEMA's PANEL_TYP (for example "Countywide, Panel Printed") and the panel's DFIRM ID.

firm_panel.other_panelsarray

Other panels covering the point, at county lines. The main panel is the one from the same DFIRM as the zone polygon, then the latest effective date.

source.dataset, source.service, source.layersstring, string, array

FEMA National Flood Hazard Layer, the map service URL, and the layers queried: 28 (Flood Hazard Zones) and 3 (FIRM Panels).

source.query_pointobject

The point sent to FEMA: your point rounded to 5 decimal places (about 1.1 m), which is also the cache key.

source.queried_atstring

When FEMA answered, ISO 8601 UTC. On a cached answer this is the original time.

source.cached, source.cache_ttl_secondsboolean, integer

Whether this answer came from the cache, and the cache lifetime (86400 seconds).

noticestring

The informational notice. Show it, or its substance, wherever you show the zone to end users.

Example: a point where two counties' panels overlap

This New Orleans point sits where Orleans Parish (22071C) and Jefferson Parish (22051C) panels overlap. The zone polygon belongs to 22071C, so that panel comes first even though the other took effect later.

curl -sG https://api.floodzoneapi.com/api/v1/flood/zone \
  -H "Authorization: Bearer $FZA_KEY" \
  -d lat=29.9511 -d lon=-90.0715

{
  "query": {
    "lat": 29.9511,
    "lon": -90.0715
  },
  "location": {
    "lat": 29.9511,
    "lon": -90.0715,
    "geocoder": null,
    "precision": "input_coordinates",
    "matched_address": null,
    "candidates": null,
    "county": null,
    "county_fips": null,
    "state": null
  },
  "flood_zone": {
    "mapped": true,
    "zone": "X",
    "subtype": "0.2 PCT ANNUAL CHANCE FLOOD HAZARD",
    "description": "0.2% annual chance flood hazard. Outside the Special Flood Hazard Area.",
    "sfha": false,
    "static_bfe": null,
    "depth": null,
    "dfirm_id": "22071C",
    "polygon_id": "22071C_10245",
    "at_zone_boundary": false,
    "other_zones": []
  },
  "firm_panel": {
    "panel": "22071C0229F",
    "effective_date": "2016-09-30",
    "panel_type": "Countywide, Panel Printed",
    "dfirm_id": "22071C",
    "other_panels": [
      {
        "panel": "22051C0225F",
        "effective_date": "2018-02-02",
        "panel_type": "Countywide, Panel Printed",
        "dfirm_id": "22051C"
      }
    ]
  },
  "source": {
    "dataset": "FEMA National Flood Hazard Layer (NFHL)",
    "service": "https://hazards.fema.gov/arcgis/rest/services/public/NFHL/MapServer",
    "layers": [
      {
        "id": 28,
        "name": "Flood Hazard Zones"
      },
      {
        "id": 3,
        "name": "FIRM Panels"
      }
    ],
    "query_point": {
      "lat": 29.9511,
      "lon": -90.0715
    },
    "queried_at": "2026-09-29T02:02:26Z",
    "cached": true,
    "cache_ttl_seconds": 86400
  },
  "notice": "Informational. This is the zone shown on FEMA's effective flood map (NFHL) at this point. It is not a Standard Flood Hazard Determination (FEMA Form 086-0-32), a prediction of flood risk, or an insurance quote, and it does not reflect a Letter of Map Amendment issued for a single structure."
}

Zone values

Response headers

What counts as a call

• Every authenticated request counts against the month's quota, including 404 address_not_found.
• 422 (bad input) and any 5xx (FEMA, the geocoder or we failed) are refunded automatically, so the quota only pays for answers.
• 401 and rate-limited requests are never metered.
• At the quota, calls return 429 quota_exceeded until the first day of the next month (UTC), or until you upgrade. There is no overage billing.
• Rate limit: 5 requests per second per key.

Caching

FEMA's answer for a point is cached for 24 hours, keyed by the point rounded to 5 decimal places (about 1.1 m), and FEMA is queried at that rounded point. Address geocodes are cached for 24 hours. Unmapped answers are never cached, because FEMA occasionally returns an empty answer for a mapped point and a second try gets the zone. source.cached and source.queried_at tell you exactly what you got.

Known limits of a zone lookup

• It reports the effective map, not flood risk, and it is not a Standard Flood Hazard Determination.
• Letters of Map Amendment (LOMAs) for single structures are not reflected. Effective Letters of Map Revision (LOMRs) are, because FEMA folds them into the NFHL polygons.
• Preliminary maps that have not taken effect are not included.
• Address-range geocoding places a house somewhere along its block face. Near a zone line, send your own rooftop or parcel coordinates.
• US states, DC, Puerto Rico, Guam, American Samoa, the Northern Mariana Islands and the US Virgin Islands only. Coverage by state.

OpenAPI

The machine-readable description is at /openapi.json (OpenAPI 3.1), for client generators and API tools.