FEMA flood zones in California

FEMA’s flood maps sort land into flood zones that lenders, insurers and local governments rely on. This guide explains the zones in plain terms and shows how to check any California location on Outpost’s free map.

Data as of October 23, 2026; refreshed monthly.

In short

The Special Flood Hazard Area is land with a 1% chance of flooding in any given year, often called the “100-year” flood.
Zones that start with A or V are in that area. Shaded Zone X is moderate hazard. Zone D means the flood hazard hasn’t been studied.
With a mortgage from a federally regulated or insured lender, flood insurance is generally required in high-risk zones. Elsewhere it is up to the lender.
No mapped zone doesn’t mean no flood risk.

Screening only — not a legal or official determination. Verify with the issuing agency.

What the zones mean

Zone	What FEMA means by it	On Outpost
A, AE, AH, AO, AR, A99	High risk: inside the Special Flood Hazard Area, the area of the flood with a 1% chance of being equaled or exceeded in any year	High risk (SFHA)
V, VE	High-risk coastal areas with an added hazard from storm waves	High risk (SFHA)
Floodway	The channel and nearby land that must stay open to carry the 1% flood; communities regulate building there	Floodway
X (shaded)	Moderate hazard: the area between the 1% and 0.2% (“500-year”) flood limits, and some areas behind levees or with shallow or small-drainage 1% flooding	Moderate (500-year) for the 0.2% area; other shaded X areas, such as behind levees, aren’t drawn
X (unshaded), C	Minimal hazard, above the 0.2% flood level	Not drawn
D	Flood risk not determined; no flood hazard analysis has been done	Undetermined

A “100-year flood” doesn’t mean once a century. It is a 1% chance every year, which adds up to about a 26% chance over 30 years.

Why the zone matters

Insurance: in communities in the National Flood Insurance Program, owners of buildings in high-risk zones with a mortgage from a federally regulated or insured lender generally must carry flood insurance. Outside those zones the lender decides. FloodSmart notes that 1 in 3 flood insurance claims come from low- and moderate-risk zones.
Building: cities and counties regulate building in mapped flood zones, and especially in floodways. The local floodplain administrator can say what applies.
Selling: California’s Natural Hazard Disclosure Statement asks whether a property is in a Special Flood Hazard Area.

How to check a location on Outpost

Open the map and search the address, or click the spot on the map.
The scorecard’s flood row shows the FEMA zone class at that point: floodway, high risk (Special Flood Hazard Area), moderate (500-year) or undetermined (Zone D).
If none of the zones Outpost draws covers the point, the row shows no flag. That can mean minimal-hazard Zone X, a moderate-hazard Zone X area that Outpost doesn’t draw (such as an area behind a levee), or an area without digital FEMA flood data, so check FEMA’s own map.
If the point is close to a zone line, the scorecard says “Near a zone boundary — verify with the official map”.
To see the zones, turn on the Flood Hazard layer. Its four parts (Floodway, High Risk, Moderate and Undetermined) can be switched on and off separately.

Flood zone colors on the map:

Floodway
High risk (A, AE)
Moderate (500-year)
Undetermined (D)

What Outpost can’t tell you

It isn’t an official flood zone determination. FEMA’s Flood Map Service Center has the effective maps.
It doesn’t show Letters of Map Amendment (LOMA or LOMR-F) that may have removed a property or building from a high-risk zone, or the base flood elevation for a building.
It draws only the 0.2% (500-year) part of moderate-hazard Zone X. Other shaded Zone X areas, such as areas behind levees, aren’t drawn; check FEMA’s map.
It doesn’t show dam-failure inundation areas (the California Department of Water Resources publishes those), local drainage flooding or post-fire debris flows.
Zone lines are simplified for the web and can lag FEMA’s updates.

Open the mapFree, no account. Search an address or click any point in California.

Common questions

How do I look up my FEMA flood zone?

FEMA’s Flood Map Service Center lets you search the effective flood map by address. Outpost shows FEMA’s National Flood Hazard Layer next to other hazards on one free map.

Is flood insurance required in Zone X?

Not by federal rules. In moderate- and low-risk zones the lender decides. FloodSmart notes that 1 in 3 flood insurance claims come from low- and moderate-risk zones.

What does Zone D mean?

FEMA hasn’t done a flood hazard analysis there, so the flood risk is undetermined. FloodSmart recommends flood insurance in Zone D.

What is a floodway?

The river or stream channel and the land next to it that must stay open to carry the 1% annual chance flood. Communities regulate building in floodways so it doesn’t raise flood levels.

Can a flood zone be changed?

Yes. When a property or building is shown to be above the base flood level, FEMA can issue a Letter of Map Amendment (or, where fill raised the ground, a Letter of Map Revision Based on Fill). A lender can then drop the federal insurance requirement.

Official sources

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