Flood zone AH: what it means for your home and insurance
Inside the 1% annual chance floodplain where flooding is shallow ponding, usually 1 to 3 feet deep.
Free property report with the FEMA flood zone plus wildfire, wind, earthquake and landslide risk. Open the full address analyzer.
What zone AH means
Zone AH is part of the Special Flood Hazard Area: land with a 1% chance of flooding in any given year. Here the expected flooding is shallow — FEMA defines AH as areas of shallow flooding, usually areas of ponding, with average depths of 1 to 3 feet.
Ponding happens where water collects in low spots with nowhere to drain. FEMA publishes a base flood elevation for AH zones from a detailed study.
FEMA calls the flood with a 1% chance of being equaled or exceeded in any given year the "base flood" (often called the 100-year flood). A 1% chance each year adds up: over 30 years it works out to roughly a 26% chance of at least one such flood.
Insurance in zone AH
This is a Special Flood Hazard Area (SFHA). Under federal law, if you have a mortgage from a federally regulated or insured lender — or a loan backed by FHA, VA, USDA, Fannie Mae or Freddie Mac — on a building in an SFHA in a community that participates in the National Flood Insurance Program (NFIP), the lender must require flood insurance. Your lender or a licensed agent can confirm what your loan requires.
Standard homeowners policies exclude flood damage. Flood coverage is bought separately, either through the NFIP or from a private flood insurer.
If you believe your building sits above the mapped flood level, a licensed surveyor or engineer can prepare an Elevation Certificate, and you can ask FEMA for a Letter of Map Amendment (LOMA) to remove the building from the SFHA.
Reducing flood risk
- Because ponding water stands rather than flows, raising the lowest floor and utilities even a few feet above the BFE can make a large difference.
- Keep storm drains and swales near the property clear so ponded water can leave.
- Get an Elevation Certificate so you know how your lowest floor compares to the base flood elevation.
- 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 AH questions
- What does flood zone AH mean?
- Zone AH is a high-risk area with a 1% annual chance of shallow flooding, usually ponding, with average depths of 1 to 3 feet. FEMA publishes a base flood elevation for it.
- Is flood insurance required in zone AH?
- AH is part of the Special Flood Hazard Area, so lenders must require flood insurance on federally regulated or backed loans in participating communities. 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 zonesThis 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.