Address lookup

Flood Zone AO

A 1% annual-chance shallow-flooding area, usually sheet flow on sloping terrain, with average depths of 1 to 3 feet.

Higher mapped risk

AO

A 1% annual-chance shallow-flooding area, usually sheet flow on sloping terrain, with average depths of 1 to 3 feet.

Special Flood Hazard Area: yes

What it means for insurance

Flood insurance is generally required for buildings in this Special Flood Hazard Area when the loan is secured by the building and made, increased, extended or renewed by a federally regulated or insured lender. Federal financial assistance can also trigger requirements.

Your lender can require coverage beyond the federal minimum. Standard homeowners insurance generally does not cover flooding.

Read the insurance rules

How it appears on a FIRM

The map gives average flood depths rather than a single base flood elevation.

A zone designation applies to the mapped area. Locate the building on the current effective panel before drawing conclusions from an address marker.

Published insurance cost context

A verified individual-zone premium range is not available. A zone alone does not determine current NFIP pricing under Risk Rating 2.0.

Get a quote for the specific building, coverage and deductible. FEMA’s pricing uses property risk factors beyond the flood zone.

How to question a designation

Check the current effective map and any letters of map change. If natural ground or the structure meets FEMA’s criteria, a Letter of Map Amendment may be appropriate. A qualified surveyor and your local floodplain administrator can explain the evidence needed.

Read the map-change guide

Questions about Zone AO

What does flood zone AO mean?

A 1% annual-chance shallow-flooding area, usually sheet flow on sloping terrain, with average depths of 1 to 3 feet.

Does zone AO require flood insurance?

Flood insurance is generally required for buildings in this Special Flood Hazard Area when the loan is secured by the building and made, increased, extended or renewed by a federally regulated or insured lender. Federal financial assistance can also trigger requirements.

Is zone AO good or bad?

The zone describes a mapped hazard category. Review the effective map, the building location and your insurance needs; a zone is not a complete property risk assessment.

How much does flood insurance cost in zone AO?

A zone alone does not determine a current NFIP premium. Risk Rating 2.0 also considers the building and its flood-risk characteristics. Published national group averages are context, not a property quote.

Can my zone change?

An updated map or an official letter of map change can alter a designation. A Letter of Map Amendment usually requires evidence that natural ground or the structure is above the applicable flood elevation. Check with FEMA and your local floodplain administrator.

Check the map at your address.

U.S. addresses only. Include a ZIP for a more precise match.

Sources and related reading

FEMA flood zone definitions

FEMA map-reading training

FloodSmart flood zones and maps

Compare every zone