Data sources
Every report shows, for each data point, the source, the exact query or page, when we retrieved it, and its limitations. These agencies are data sources only; they do not endorse Home Prep Report.
Census Geocoder (Public_AR_Current)
U.S. Census Bureau · Authoritative government source
- Coverage
- United States, Puerto Rico, Island Areas
- Updates
- Address ranges updated with each TIGER/Line benchmark
- License
- Public domain (U.S. Government work)
- Limitations
- Matches against address ranges; the point is interpolated along the street and may be offset from the actual structure. New construction may not match.
- Homepage
- https://geocoding.geo.census.gov/geocoder/
National Flood Hazard Layer (NFHL)
Federal Emergency Management Agency · Authoritative government source
- Coverage
- Communities with digital Flood Insurance Rate Maps; not all areas are digitized
- Updates
- Continuously as map revisions become effective
- License
- Public domain (U.S. Government work)
- Limitations
- Absence of a mapped zone does not mean an area cannot flood. Some areas only have scanned paper maps (check FEMA Map Service Center). Not a substitute for an elevation certificate.
- Homepage
- https://www.fema.gov/flood-maps/national-flood-hazard-layer
National Risk Index (census tract)
Federal Emergency Management Agency · Authoritative government source
- Coverage
- All U.S. census tracts
- Updates
- Periodic releases (version shown in report)
- License
- Public domain (U.S. Government work)
- Limitations
- Ratings are relative to other U.S. tracts and describe community-level expected loss, not the risk to a specific house.
- Homepage
- https://hazards.fema.gov/nri/
National Weather Service API (points, forecasts, active alerts)
NOAA National Weather Service · Authoritative government source
- Coverage
- United States and territories
- Updates
- Alerts in near real time; forecasts several times daily
- License
- Public domain (U.S. Government work)
- Limitations
- Alerts shown were active at retrieval time only. Always check weather.gov or local media for current conditions. A printed report cannot update itself.
- Homepage
- https://www.weather.gov/documentation/services-web-api
Elevation Point Query Service (3DEP)
U.S. Geological Survey · Authoritative government source
- Coverage
- United States
- Updates
- As 3DEP elevation data is updated
- License
- Public domain (U.S. Government work)
- Limitations
- Ground elevation at the geocoded point, not first-floor elevation of the structure.
- Homepage
- https://apps.nationalmap.gov/epqs/
ComCat earthquake catalog (FDSN event service)
U.S. Geological Survey · Authoritative government source
- Coverage
- Global; U.S. catalog completeness varies by region and era
- Updates
- Near real time
- License
- Public domain (U.S. Government work)
- Limitations
- Historical counts of recorded events are not a forecast.
- Homepage
- https://earthquake.usgs.gov/fdsnws/event/1/
OpenStreetMap (via Overpass API)
OpenStreetMap contributors · Community / secondary source
- Coverage
- Global, community maintained
- Updates
- Continuous community edits
- License
- Open Database License (ODbL) — attribution required: © OpenStreetMap contributors
- Limitations
- Community data: facilities may be missing, closed, or mislabeled. A mapped hospital may not be accessible during a disaster; a mapped AED may not be publicly accessible. Confirm by phone.
- Homepage
- https://www.openstreetmap.org/copyright
FEMA ESF#6 Shelter System — Open Shelters
Federal Emergency Management Agency / American Red Cross · Authoritative government source
- Coverage
- Shelters reported open by participating organizations
- Updates
- Near real time during activations
- License
- Public domain (U.S. Government work)
- Limitations
- Lists only shelters reported open at retrieval time. Local shelters are announced by county/municipal emergency management during an event; none are reliably pre-assigned.
- Homepage
- https://gis.fema.gov/arcgis/rest/services/NSS/OpenShelters/MapServer
NOAA Weather Radio county coverage listing
NOAA National Weather Service · Authoritative government source
- Coverage
- United States
- Updates
- As transmitters change
- License
- Public domain (U.S. Government work)
- Limitations
- Reception depends on terrain, building construction, and receiver quality. Test reception at home.
- Homepage
- https://www.weather.gov/nwr/
Safe Drinking Water Information System (Envirofacts)
U.S. Environmental Protection Agency · Authoritative government source
- Coverage
- Public water systems in the United States
- Updates
- Quarterly
- License
- Public domain (U.S. Government work)
- Limitations
- Systems are listed by the city they report, not by service area; we cannot confirm which system serves an address. Private wells are not regulated or listed.
- Homepage
- https://www.epa.gov/enviro/sdwis-overview
Hospital General Information (Care Compare)
Centers for Medicare & Medicaid Services; locations geocoded with the U.S. Census Geocoder (OpenStreetMap Nominatim as fallback) · Authoritative government source
- Coverage
- Medicare-certified hospitals in the United States
- Updates
- Quarterly
- License
- Public domain (U.S. Government work)
- Limitations
- Lists Medicare-certified hospitals and whether they report providing emergency services. Locations are geocoded from the listed address (a few addresses can't be matched). It doesn't tell you whether an emergency department is open, on diversion, or reachable during a disaster. Distances are straight-line.
- Homepage
- https://data.cms.gov/provider-data/dataset/xubh-q36u
Home Prep Report verified directory of state and county emergency resources
Home Prep Report (links to official agencies) · Community / secondary source
- Coverage
- 50 states + DC; selected counties
- Updates
- Manually verified (date shown)
- License
- Links only
- Limitations
- Links were confirmed to resolve on the date shown; agencies reorganize sites. Search the agency name if a link moves.
- Homepage
- State/county links verified 2026-11-04
The National Map — USGS Topo basemap
U.S. Geological Survey · Authoritative government source
- Coverage
- United States
- Updates
- Periodic
- License
- Public domain (U.S. Government work)
- Limitations
- Cartographic basemap; not survey grade.
- Homepage
- https://basemap.nationalmap.gov/