Privacy Policy
Last updated: March 4, 2026
🔒 Short version
FloodCheck collects no personal data. It has no accounts, no tracking, no analytics, and no servers of its own. Everything happens in your browser using free public government APIs.
1. What FloodCheck is
FloodCheck is a free Chrome browser extension and companion website that displays official FEMA National Flood Hazard Layer (NFHL) flood zone data on real estate listing pages (Zillow, Realtor.com, Redfin, and HAR.com). It also provides a standalone address lookup tool at floodcheck.vercel.app.
2. Data we do NOT collect
- No names, email addresses, or account information
- No browsing history or URLs you visit
- No search queries you enter on real estate sites
- No property addresses you look up
- No device identifiers, IP addresses, or fingerprinting data
- No cookies, local storage, or persistent data of any kind
- No analytics, crash reports, or telemetry
3. What the extension does
When you visit a supported real estate listing page, the extension:
- Reads the property's latitude and longitude from the page (from the site's own embedded data — we do not scrape personally identifiable information).
- Sends those coordinates directly to the FEMA NFHL ArcGIS REST API (
hazards.fema.gov) — a free, public government service — to retrieve the official flood zone designation. - If coordinates are unavailable, sends the property address to Nominatim (OpenStreetMap) or the U.S. Census Geocoder — both free, public services — to determine the coordinates, then queries FEMA as above.
- Website only: As you type in the address search box, the website sends your partial query to Geoapify — a free geocoding service (3,000 req/day free tier) — to show address suggestions in real time. No query is stored or linked to you. When you select a suggestion, coordinates come from Geoapify directly, and the FEMA lookup skips geocoding entirely.
- Displays the result directly on your screen. Nothing is stored.
These requests go directly from your browser to FEMA/OSM/Census. FloodCheck has no backend servers that receive or log your queries.
4. Third-party services contacted
| Service | Purpose | Data sent | Privacy policy |
|---|---|---|---|
| FEMA NFHL API | Flood zone lookup | Lat/lng coordinates | fema.gov |
| Geoapify | Address autocomplete (website only) | Partial address typed in search box | geoapify.com |
| Nominatim (OSM) | Address geocoding (fallback) | Property address | osmfoundation.org |
| U.S. Census Geocoder | Address geocoding (fallback) | Property address | census.gov |
Geocoding only occurs when coordinates are not directly available in the listing page's structured data. In most cases, only FEMA is contacted.
5. Permissions explained
The extension requests the following Chrome permissions:
- Host permissions for zillow.com, har.com, realtor.com, redfin.com: Required to inject the FEMA flood zone panel into listing pages. The extension reads publicly visible page content only — not form inputs, passwords, or any data not already displayed on screen.
- Host permissions for hazards.fema.gov, nominatim.openstreetmap.org, geocoding.geo.census.gov: Required so the background service worker can call these public APIs on your behalf (bypasses browser CORS restrictions for these specific government domains).
- storage: Used only to save your per-site enable/disable toggle preferences locally on your device. No data leaves your browser.
6. Children's privacy
FloodCheck does not collect any information from anyone, including children under the age of 13. The service is a passive data display tool with no user accounts or data submission.
7. Changes to this policy
If this policy changes materially, the "Last updated" date at the top of this page will be updated. Because we collect no contact information, we cannot notify users directly — we recommend checking this page if you have questions.
8. Contact
Questions about this privacy policy can be submitted via the GitHub Issues page.