California flood zone map and environmental check
California is the one state where people search for a Phase I by name (about 1,300 a month). The state keeps two big public cleanup databases, and its Department of Water Resources maps floodplains FEMA hasn't, especially in the Central Valley.
Check a California property’s flood zone free
Type the address. See the FEMA flood zone and map, free. Add your email to see which buildings sit in the flood area.
Official flood maps for California
FEMA’s Flood Map Service Center has the effective flood map for every California address. The state also runs:
California Department of Water Resources
FEMA zones plus state and local floodplain maps, including 200-year floodplains in the Central Valley.
Map tools usually show the zone at the address pin. On a commercial lot, the buildings can sit in a different zone than the pin. Our free check shows which buildings are in the 1% and 0.2% annual-chance flood areas.
Contamination and tank records in California
State Water Resources Control Board
Leaking tank and groundwater cleanup cases, with reports, by address.
Department of Toxic Substances Control
Hazardous substance cleanup sites and permitted facilities.
A listed site next door matters as much as one on your lot: leaks travel with groundwater. Look at what’s around the property, not only the address.
What our report checks for a California property
- FEMA's National Flood Hazard Layer: the flood zone under each building, not just the pin
- FEMA flood insurance claims history for the area (OpenFEMA)
- USACE National Levee Database
- EPA lists: Superfund (NPL and delisted), SEMS, RCRA corrective action and hazardous waste handlers, brownfields (ACRES), PFAS layers
- EPA UST Finder for underground storage tanks and leaks
- EPA ECHO air permits that flag dry cleaners
- Aerial photos back through the decades (USGS, NAIP, Esri Wayback) and Sanborn fire insurance maps where the Library of Congress has them
Every source is marked checked, not found or not checked. A source we couldn’t reach is listed as a gap, never as a clean result. It is a desk screen, not a Phase I.
Questions buyers ask
Other states
Sources (checked 2026-11-10)