Flood Data API Response Fields

The National Flood Data API returns a structured set of flood risk attributes for a property, derived from FEMA flood maps, geospatial flood hazard datasets, and parcel and building footprint geometry. These attributes support flood zone determinations, underwriting analysis, property risk assessment and automated decision systems used by insurers, lenders and data platforms.

Each API request returns a JSON response containing normalized flood risk data associated with the queried property location. The response includes FEMA flood zone classifications, base flood elevation (BFE), flood map panel identifiers and effective dates, proximity measurements to mapped flood hazards, property year built and square footage and spatial relationships between flood zones and parcel or building footprint geometry.

Response Structure

The National Flood Data API returns a structured JSON response containing normalized flood risk attributes associated with the queried property location.

The response contains several categories of flood risk data, including:

FEMA flood zone and map panel information
Base flood elevation (BFE) values
Distances to mapped flood hazards
Parcel and building footprint intersections
Property year built and square footage
Supporting flood risk metadata

These attributes include FEMA flood zone classifications, base flood elevation (BFE), proximity to mapped flood hazards, parcel and building footprint intersections and flood map panel metadata.

Example National Flood Data API JSON Response

The example below shows a typical JSON response returned by the National Flood Data API for a residential property query. The expandable example illustrates the overall structure of the response object and the categories of data returned.

Example JSON Response

Field Reference

The following sections document each field returned by the National Flood Data API. Fields are grouped by category to reflect the logical structure of the response and to make it easier to understand how each attribute contributes to flood risk analysis.

For full integration instructions, request parameters, and endpoint documentation, see the API Documentation.

The National Flood Data API returns the complete flood data for an entire property parcel based on the address provided.

All flood polygons that the parcel intersects are returned as a list ordered by flood risk severity. For example, if half a parcel is in a Special Flood Hazard Area and half is not, the list contains both zones ordered accordingly.

Field	JSON Key	Type	Description
Flood Zone (e.g. A, V, X etc)	s_fld_haz_ar -> fld_zone	`string`	FEMA flood zone designation of the property based on FEMA National Flood Insurance Program maps.
Flood Zone Subtype	s_fld_haz_ar -> zone_subty	`string`	Flood zone subtype that can take 30 different values and distinguishes between 100 and 500 year flood plains.
Special Flood Hazard Area (T/F)	s_fld_haz_ar -> sfha_tf	`string (Y/N)`	True or False value that states whether or not the location is in a Special Flood Hazard Area.
DFIRM ID (Generally the County FIPS Code)	s_fld_haz_ar -> dfirm_id	`string`	The Digital Flood Insurance Rate Map ID, which is generally the county FIPS identifier.
Polygon IDs	s_fld_haz_ar -> fld_ar_id	`string`	Unique identifier for the flood polygons.
Version ID	s_fld_haz_ar -> version_id	`string`	ID of the specific NFIP guidelines according to which the flood zone was determined.
Panel Number	s_firm_pan -> firm_pan	`string`	Panel within the NFIP map that contains the location.
Panel Type	s_firm_pan -> panel_typ	`string`	States the geographic applicability of the panel, i.e. County or Community.
Effective Date	s_firm_pan -> eff_date	`string (YYYY-MM-DD)`	Date on which the panel became effective.
Community Name	s_firm_pan -> comm_name	`string`	Name of the Community, general the county or town name.
Community Participation	s_pol_ar -> community -> comm_part	`boolean`	Whether or not the community participates in the National Flood Insurance Program.
Community ID	s_pol_ar -> cid	`integer`	Unique Community ID number.
Tribal Status in NFIP Community Status Book	s_pol_ar -> community -> tribal	`string (Yes/No)`	Whether or not the community is governed by a tribal government rather than county or township.
Date of First Flood Hazard Boundary Map	s_pol_ar -> community -> fhbm	`string (DDMMYY)`	Date on which the first National Flood Insurance Plan map was made available for the region.

Field	JSON Key	Type	Description
Elevation of property	elevation -> propertyelevation	`numeric`	Elevation at the center of the property in feet as provided by the US Geological Survey.
Base Flood Elevation	elevation -> flood.basefloodelevation -> elevation	`numeric`	Estimated elevation of water in the case of a flood.
Base Flood Elevation Type (provided, extrapolated, interpolated)	elevation -> flood.basefloodelevation -> bfe_type	`string`	How the base flood elevation was determined: provided by FEMA or interpolated or extrapolated from FEMA data.
Distance to Base Flood Elevation Polygon	elevation -> flood.basefloodelevation -> distkm	`numeric`	Distance from the parcel to the nearest base flood elevation polygon provided by FEMA.
Vertical Datum	elevation -> flood.basefloodelevation -> v_datum	`string`	Datum used to determine the base flood elevation.
Flood Zone at Base Flood Elevation	elevation -> flood.basefloodelevation -> fld_zone	`string`	The FEMA flood zone at the location of nearest provided base flood elevation.
Base Flood Elevation Source ID	elevation -> flood.basefloodelevation -> bfe_ln_id	`string`	Unique identifier of the nearest provided base flood elevation polygon.

The National Flood Data API returns several different types of bodies of water within 25 miles of the parcel. The first is general and includes all bodies of water, while others are specific, such as rivers and areas within a coastal barrier.

Each type of body of water is returned as a list of such bodies of water with fields corresponding to each, such as a list of rivers within 25 miles of the property and the name, distance and nearest points for each of these.

The latitude and longitude of the two closest points within the body of water and the parcel are provided so that underwriters can record these or view these on a digital map.

Field	JSON Key	Type	Description
Distance to nearest body of water	waterbody -> distkm	`numeric`	Distance to each sizeable body of wate within 25 miles, i.e. larger than a pond or stream.
Name of nearest body of water	waterbody -> name	`string`	Name of each body of water within 25 miles.
Location of Nearest Point within Nearest Body of Water	waterbody -> closestpoint.lat, closestpoint.lng	`numeric`	Latitude and longitude of the point within the body of water closest to the parcel.
Location of Point with Property closest to Nearest Body of Water	waterbody -> closestpoint_property.lat,closestpoint_property.lng	`numeric`	Latitude and longitude of the point within the parcel of water closest to the body of water.
Distance to Nearest River	river -> distkm	`numeric`	Distance to rivers within 25 miles of the parcel.
Name of Nearest River	river -> name	`string`	Name of the river.
Location of Nearest Point within Nearest River	river -> closestpoint.lat, closestpoint.lng	`numeric`	Latitude and longitude of the point within the river closest to the parcel.
Location of Point with Property Closest to Nearest River	river -> closestpoint_property.lat,closestpoint_property.lng	`numeric`	Latitude and longitude of the point within the parcel closest to the river.
Distance to Coastline	coastline -> distkm	`numeric`	Distance to nearest coastline if less than 25 miles.
Location of Nearest Point on Coastline	coastline -> closestpoint.lat, closestpoint.lng	`numeric`	Latitude and longitude of the point within the coastline closest to the parcel.
Location of Point with Property Closest to Coastal Body of Water	waterbody_coastal -> closestpoint_property.lat,closestpoint_property.lng	`numeric`	Latitude and longitude of the point within the parcel of closest to the coastal body of water.
Distance to Nearest Coastal Bodies of Water (e.g. a bay or intracoastal waterway)	waterbody_coastal -> distkm	`numeric`	Distance to coastal bodies of water less than 25 miles.
Name of Nearest Coastal Body of Water	waterbody_coastal -> name	`string`	Name of coastal body of water.
Location of nearest point within Coastal Body of Water	waterbody_coastal -> closestpoint.lat, closestpoint.lng	`numeric`	Latitude and longitude of the point within the coastal body of water closest to the parcel.
Location of Point with Property Closest to Coastal Body of Water	waterbody_coastal -> closestpoint_property.lat,closestpoint_property.lng	`numeric`	Latitude and longitude of the point within the parcel of closest to the coastal body of water.
Distance to Coastal Barriers	coastalbarrier -> distkm	`numeric`	Distance to coastal barriers less than 25 miles.
Name of Nearest Coastal Barrier	coastalbarrier -> name	`string`	Name of coastal barrier.
Coastal Barrier Resources System Type	coastalbarrier -> cbrs_type	`string`	Type of barrier in the Coastal Barrier Resources System.
Flood Insurance Date	coastalbarrier -> fi_date	`string`	Flood Insurance Date within the Coastal Barrier Resources System.
System Unit Date	coastalbarrier -> su_date	`string`	System Unit Date within the Coastal Barrier Resources System.
Location of Nearest Point within Nearest Coastal Barrier	coastalbarrier -> closestpoint.lat, closestpoint.lng	`numeric`	Latitude and longitude of the point within the coastal barrier closest to the parcel.
Location of Point with Property Closest to Coastal Barrier	coastalbarrier -> closestpoint_property.lat,closestpoint_property.lng	`numeric`	Latitude and longitude of the point within the parcel of closest to the coastal barrier.
Distance to Coastal Barrier Buffers	coastalbarrier_buffer -> distkm	`numeric`	Distance to coastal barrier buffers less than 25 miles.
Location of Nearest Point within Nearest Coastal Barrier Buffer	coastalbarrier_buffer -> closestpoint.lat, closestpoint.lng	`numeric`	Latitude and longitude of the point within the coastal barrier buffer closest to the parcel.
Location of Nearest Point within Nearest Coastal Barrier Buffer	coastalbarrier_buffer -> closestpoint_property.lat,closestpoint_property.lng	`numeric`	Latitude and longitude of the point within the parcel of closest to the coastal barrier buffer.

Field	JSON Key	Type	Description
Storm Surge Expected Flood Height for Category 1 Storm	stormsurge -> 1	`numeric`	Estimated height of water in the even of a Category 1 storm.
Storm Surge Expected Flood Height for Category 2 Storm	stormsurge -> 2	`numeric`	Estimated height of water in the even of a Category 2 storm.
Storm Surge Expected Flood Height for Category 3 Storm	stormsurge -> 3	`numeric`	Estimated height of water in the even of a Category 3 storm.
Storm Surge Expected Flood Height for Category 4 Storm	stormsurge -> 4	`numeric`	Estimated height of water in the even of a Category 4 storm.
Storm Surge Expected Flood Height for Category 5 Storm	stormsurge -> 5	`numeric`	Estimated height of water in the even of a Category 5 storm.

Field	JSON Key	Type	Description
LOMA Case Number	casenumber	`string`	Case number of the the LOMA.
LOMA Date Ended	dateended	`string (YYYY-MM-DD)`	Date of LOMA determination.
LOMA Determination	determinat	`string`	Format of determination, generally determination letter.
LOMA Distance	miles	`numeric`	Distance from the property to the center of the region for which the LOMA applies.
LOMA PDF Link	pdfhyperli	`string`	URL link to the pdf of the LOMA determination.
LOMA project category	projectcat	`string`	Category of amendment, e.g. based on natural ground, fill, floodway or coastal high-hazard area.
LOMA project name	projectnam	`string`	Name of LOMA project, generally the specific address or description of the small region.
LOMA status	status	`string`	Status of the LOMA (either Completed or null).
LOMA latitute	lat	`numeric`	Latitude of center of region for which the LOMA applies.
LOMA Longitude	lon	`numeric`	Longitude of center of region for which the LOMA applies.

Parcel and property data are essential for underwriting and getting quotes from carriers. The physical property data, such as viewing the boundary of the property and the building footprint overlaid with flood zone polygons are essential for underwriting.

The year built, square footage and whether or not the property is owner-occupied are generally required when requesting quotes from carriers.

Field	JSON Key	Type	Description
Parcel Identification Number	parcel_id	`string`	Unique county identifier for the parcel.
Address Number	addr_number	`numeric`	Street number of the parcel.
Address Street Name	addr_street_name	`string`	Street name of the parcel.
Address Street Type	add_street_type	`string`	Street type of the parcel, e.g. Road, Avenue.
Address City	add_city	`string`	City name of the parcel.
State	state_abbr	`string`	State abbreviation of the parcel.
Address ZIP Code	addr_zip	`string`	Zip code of the parcel.
Address Zip Plus Four	add_zipplusfour	`string`	Zip code with four digit extension of the parcel.
Owner	owner	`string`	Name of the parcel owner.
Mailing Address Number	mail_addressnumber	`string`	Street number of the owner's mailing address.
Mailing Address Street Name	mail_streetname	`string`	Street name of the owner's mailing address.
Mailing Address Street Type	mail_streetnameposttype	`string`	Street type of the owner's mailing address.
Mailing Address City	mail_placename	`string`	City name of the owner's mailing address.
Mailing Address State	mail_statename	`string`	State abbreviation of the owner's mailing address.
Mailing Address Zip Code	mail_zipcode	`string`	Zip code of the owner's mailing address.
Market Value Land	mkt_val_land	`numeric`	County assessed market value of the parcel land.
Market Value Building	mkt_val_bldg	`numeric`	County assessed market value of the buildings on the parcel.
Market Value Total	mkt_val_tot	`numeric`	County assessed total value of the land and buildings on the parcel.
Year Built	year_built	`integer`	Year in which the primary building on the parcel was built.
Acreage	acreage	`numeric`	Area of the parcel in acres.
Owner Occupied	owner_occupied	`boolean`	Whether or not the building is occupied by the owner (true/false)
Number of Buildings	buildings	`integer`	Number of free standing buildings on the parcel.
Land Cover	land_cover: has multiple subfields	`string`	Type and acreage of crop cover based on USDA Land Cover Data Layer
Crop Cover	crop_cover: has multiple subfields	`string`	Type and acreage of crop cover based on USDA Cropland Data Layer
Building Polygons	buildings_poly (geojson)	`GeoJSON`	Building polygons in geojson format.
Flood Zones Interstecting Building Polygons	s_fld_haz_ar (array)	`array`	Flood zone and related data for FEMA NFIP polygons intersecting the building polygons.
Parcel Geometry	geom_as_geojson	`GeoJSON`	Polygon of the parcel in geojson format.

Download Example JSON

Flood Data API Response Fields

Response Structure

Example National Flood Data API JSON Response

Field Reference

FEMA Flood Zone Data

Elevation and Base Flood Elevation Data

Water Body Data

Storm Surge Data

Letter of Map Amendment (LOMA)

Parcel and Property Data