Flood Zone AH: What It Means
A shallow-ponding high-risk zone with a Base Flood Elevation. Flood insurance is required for federally-backed mortgages.
What is Flood Zone AH?
Zone AH is a Special Flood Hazard Area subject to shallow flooding by ponding -- still water that accumulates rather than flows. Unlike Zone AO (which involves moving sheet flow), Zone AH water sits and rises. FEMA establishes a Base Flood Elevation (BFE) for Zone AH, representing the expected water surface elevation during the 100-year flood.
Risk Level: High risk
Zone AH typically appears in low-lying areas that drain slowly, such as land behind berms or in shallow depressions. Flood depths are usually 1 to 3 feet. Ponded water may persist for hours or days after heavy rainfall. Properties with federally-backed mortgages in Zone AH are required to carry flood insurance. Elevation above the BFE is typically required for new construction.
Flood Insurance in Zone AH
Flood insurance is typically required for properties in Zone AH when the mortgage is federally backed or regulated (FHA, VA, or conventional loans through Fannie Mae or Freddie Mac). This applies across all states -- it is a federal law, not a lender option.
Even if your mortgage is paid off, your lender no longer requires it, or you rent the property, flood insurance is strongly recommended for properties in Zone AH. Standard homeowner's insurance does not cover flood damage. A single flood event can cause tens of thousands of dollars in losses.
Flood insurance through the National Flood Insurance Program (NFIP) covers the structure and its contents. Private flood insurance is also available and may offer broader coverage or lower premiums in some cases. For a loan, your lender may want an official elevation certificate from a licensed surveyor.
Base Flood Elevation (BFE) in Zone AH
Zone AH has a published Base Flood Elevation -- the height floodwater is expected to reach during a 100-year flood event. The specific BFE varies by location and is shown on FEMA's Flood Insurance Rate Map (FIRM) for your area.
New construction in Zone AH must typically have its lowest floor at or above the BFE. If your existing home's lowest floor is above the BFE, you may qualify for lower flood insurance premiums -- and potentially for a Letter of Map Amendment (LOMA) that officially removes your property from the SFHA. A licensed surveyor can certify an Elevation Certificate documenting your floor elevation relative to the BFE.
Schematic: Zone AH Cross-Section
This diagram shows how Zone AH relates to flood elevation and the landscape.
Compare: Zone AH vs. Related Zones
- AE High risk The most common high-risk flood zone. Flood insurance is typically required for federally-backed mortgages.
- AO High risk A shallow-flooding high-risk zone where water typically moves as sheet flow rather than rising in a channel. Flood insurance is required.
- X Lower risk A low-risk flood zone outside the Special Flood Hazard Area. Flood insurance is not required but is often available at lower rates.
Check If YOUR Address Is in Zone AH
The only way to know your exact zone is to check your specific address against FEMA's official maps -- free and instant below.
Frequently Asked Questions about Zone AH
- What is Flood Zone AH?
- Zone AH is a Special Flood Hazard Area subject to shallow flooding by ponding -- still water that accumulates rather than flows. Unlike Zone AO (which involves moving sheet flow), Zone AH water sits and rises. FEMA establishes a Base Flood Elevation (BFE) for Zone AH, representing the expected water surface elevation during the 100-year flood.
- Is Flood Zone AH bad?
- Zone AH typically appears in low-lying areas that drain slowly, such as land behind berms or in shallow depressions. Flood depths are usually 1 to 3 feet. Ponded water may persist for hours or days after heavy rainfall. Properties with federally-backed mortgages in Zone AH are required to carry flood insurance. Elevation above the BFE is typically required for new construction.
- Do I need flood insurance in Zone AH?
- In Zone AH (a Special Flood Hazard Area), federally backed and regulated mortgage lenders typically require flood insurance. Even if your mortgage is paid off or not federally backed, flood insurance is strongly recommended given the elevated risk.
- What is the Base Flood Elevation (BFE) in Zone AH?
- In Zone AH, FEMA establishes a Base Flood Elevation (the height floodwater is expected to reach during a 100-year flood event). The specific BFE varies by location -- it is shown on FEMA's Flood Insurance Rate Maps. New construction in Zone AH is typically required to have its lowest floor at or above the BFE.