What does X500 mean on a flood map?

X500 refers to shaded zone X: the 0.2% annual chance (500-year) floodplain, plus areas of shallow 1% annual chance flooding and areas protected by levees. It is a moderate flood hazard area outside the Special Flood Hazard Area.

Is zone B the same as shaded zone X?

Yes. Older FEMA maps labeled moderate flood hazard areas zone B; newer maps show them as shaded zone X.

Do I need flood insurance in shaded zone X?

Federal law does not require it outside the Special Flood Hazard Area, but a lender may. Homeowners policies still exclude flood. Your lender or a licensed agent can confirm.

Flood zone X (shaded): what it means for your home and insurance

Moderate riskAlso shown as X500, B, 0.2% annual chance flood hazard

Moderate flood hazard: the 0.2% annual chance (500-year) floodplain, or areas with shallow or levee-reduced 1% annual chance flooding.

Free property report with the FEMA flood zone plus wildfire, wind, earthquake and landslide risk. Open the full address analyzer.

What zone X (shaded) means

Shaded zone X — labeled zone B on older maps and often written X500 — is a moderate flood hazard area. It sits outside the Special Flood Hazard Area.

FEMA uses it for three kinds of land: areas with a 0.2% chance of flooding in any given year (the 500-year flood); areas in the 1% annual chance flood where average depths are less than 1 foot or the drainage area is less than 1 square mile; and areas protected from the 1% annual chance flood by a levee.

Moderate is not zero. Floods larger than the base flood happen, local drainage can overwhelm, and levees can be overtopped or fail.

Insurance in zone X (shaded)

Federal law does not require flood insurance for buildings outside a Special Flood Hazard Area, but a lender may still require it as a condition of the loan. Your lender or a licensed agent can confirm.

Standard homeowners policies exclude flood damage. Flood coverage is bought separately, either through the NFIP or from a private flood insurer.

Flood insurance is available outside high-risk zones through the NFIP (in participating communities) and private insurers. NFIP policies generally have a 30-day waiting period before coverage starts, so it is not something to buy when a storm is forecast.

Reducing flood risk

Raise furnaces, water heaters, electrical panels and HVAC equipment above expected flood levels.
Use flood-resistant materials (tile, concrete, closed-cell insulation) below the base flood elevation.
Install a backflow valve so floodwater cannot push sewage back into the house.
Grade soil away from the foundation and keep gutters, downspouts and drains clear.

Your community’s floodplain administrator can tell you which building requirements apply locally.

Zone X (shaded) questions

What does X500 mean on a flood map?: X500 refers to shaded zone X: the 0.2% annual chance (500-year) floodplain, plus areas of shallow 1% annual chance flooding and areas protected by levees. It is a moderate flood hazard area outside the Special Flood Hazard Area.
Is zone B the same as shaded zone X?: Yes. Older FEMA maps labeled moderate flood hazard areas zone B; newer maps show them as shaded zone X.
Do I need flood insurance in shaded zone X?: Federal law does not require it outside the Special Flood Hazard Area, but a lender may. Homeowners policies still exclude flood. Your lender or a licensed agent can confirm.

Check the flood zone for any address

We look up the address in FEMA’s National Flood Hazard Layer and show the zone alongside the rest of the property’s risk profile.

Free property report with the FEMA flood zone plus wildfire, wind, earthquake and landslide risk. Open the full address analyzer.

Other flood zones

All FEMA flood zones

This page is general education about FEMA flood zone designations, not insurance or legal advice and not an offer of coverage. Zone definitions come from FEMA’s Flood Insurance Rate Maps; maps change, and the official map for any property is on the FEMA Flood Map Service Center. Your lender or a licensed agent can confirm the flood insurance requirements for a specific home.