Data sources
Every figure on a report comes from one of these public datasets. Versions and dates are the ones used in the current build.
Datasets
| Dataset | Used for | Terms |
|---|---|---|
| National Risk Index, v1.20 (December 2025)FEMA | USPR Score and hazard table: expected annual building loss and building value by census tract | US Government data; FEMA attribution statement below |
| National Flood Hazard Layer (effective maps)FEMA; national GeoParquet snapshot compiled July 2026 | Flood zones, base flood elevations | Public domain |
| USA Structures, Florida (June 2025)FEMA and Oak Ridge National Laboratory | Building locations and occupancy for flood, sea level and noise counts | US Government data |
| NFIP Redacted Policies v3 and Claims v3FEMA (OpenFEMA) | Policies in force on August 31, 2026, policy costs, claims 1978–2026 | OpenFEMA terms; attribution statement below |
| NFIP Community Status Book and residential penetration ratesFEMA (OpenFEMA) | Community Rating System class and discounts, map dates, county insured shares | OpenFEMA terms |
| Disaster Declarations Summaries v2FEMA (OpenFEMA) | Major disaster declarations by county | OpenFEMA terms |
| Final Flood Hazard Determinations, 91 FR 65238FEMA, Federal Register, October 14, 2026 | Miami-Dade new map effective date, February 19, 2027 | Public domain |
| Superfund National Priorities List sites with statusEPA, layer edited September 30, 2026 | NPL sites, status and dates | Public domain |
| Toxics Release Inventory basic data, reporting year 2024EPA | Facilities reporting toxic releases and on-site release totals | Public domain |
| Facility Registry Service national file (October 2026)EPA | Brownfields, other Superfund-program sites, large-quantity hazardous waste generators | Public domain |
| Wildfire Hazard Potential 2023, ZIP code summaryUSDA Forest Service (Dillon 2023, doi 10.2737/RDS-2015-0047-4) | Share of land in each wildfire hazard class | US Government data, cite the authors |
| Sea Level Rise Viewer extent rastersNOAA Office for Coastal Management | Buildings inside the 1, 2 and 3 ft extents | Public domain |
| 2022 Interagency Sea Level Rise Technical Report dataNOAA and interagency task force (Sweet et al. 2022) | Projections at the Virginia Key tide gauge | Public domain |
| National Transportation Noise Map, 2020 aviation layerUS DOT Bureau of Transportation Statistics | Modelled aviation noise at buildings | Public use |
| Map of Radon Zones (1993)EPA | County radon zone | Public domain |
| ZIP code tabulation areas and 2020 relationship filesUS Census Bureau (TIGER/Line 2025, 2020 Census) | ZIP areas, housing-unit weights, counties and places | Public domain |
| US postal codesGeoNames (geonames.org) | Postal city names | Creative Commons Attribution 4.0 |
Required statements
This product uses the FEMA National Risk Index dataset and the Federal Emergency Management Agency's OpenFEMA API and downloadable datasets, but is not endorsed by FEMA. The Federal Government or FEMA cannot vouch for the data or analyses derived from these data after the data have been retrieved from the Agency's website(s).
Postal city names: GeoNames, licensed under CC BY 4.0. Wildfire hazard: Dillon, G.K. 2023, Wildfire Hazard Potential for the United States (270 m), version 2023, 4th edition, Forest Service Research Data Archive.
None of the agencies above has reviewed or endorsed this site. Derived figures, such as USPR Scores, building counts and medians, are our calculations; the methodology explains each one.
Refresh schedule
NFIP policy and claims files are refreshed at least every quarter; the National Risk Index when FEMA publishes a new version (recently each December); EPA's NPL layer and TRI as EPA releases them; flood maps when a county's new maps take effect, starting with Miami-Dade after February 19, 2027. Each report states when its data were compiled.