BuildabilityFree flood zone check · No signup
Which side of the flood line?
FEMA’s flood zone at any mapped U.S. address, read from the National Flood Hazard Layer.
Or try one:
FEMA National Flood Hazard Layer · Buffalo Bayou and White Oak Bayou, Houston · read Nov 2, 2026
1% a year, 26% over 30 years.
The SFHA is mapped by the 1% annual chance flood. Held for a 30-year mortgage, those odds compound.
Every FEMA flood zone fact is free.
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- FEMA zone, SFHA and floodway
- Base flood elevation, where FEMA publishes one
- Share of the lot in an SFHA, when the county outline matches
- The exact FEMA query, and when it was read
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- Owner, parcel number and the assessor record
- Height, setbacks and floor area, where the code is read
- Valuation and comparable sales
- Free re-runs
Go deeper
Flood zones, in full
What each FEMA code means for building, what it does to the Score, and what to do when the map looks wrong.
A, AE, V and VE are the 1% flood. X is outside it.
FEMA’s zones, hardest constraint first. The 1% annual chance flood is the base flood.
| Zone | What FEMA maps | For building and insurance |
|---|---|---|
| Floodway | The regulatory floodway: the channel that must stay clear to carry flood water. | The strongest flood constraint on the map. New structures typically need a no-rise engineering certification and are often barred outright. Caps the Score at 25. |
| A and AE | Special Flood Hazard Area: land flooded by the 1% annual chance (base) flood. AE is mapped with a base flood elevation; the check shows it where FEMA publishes one. | The mandatory purchase of flood insurance applies, and the NFIP floodplain rules must be enforced on new building. |
| AH and AO | Shallow flooding in the 1% annual chance flood. | Part of the Special Flood Hazard Area. |
| V and VE | Special Flood Hazard Area on the coast: a 1% or greater chance of flooding, with an added storm-wave hazard. | The mandatory purchase of flood insurance applies, as in Zone A. |
| X, shaded | Moderate hazard: between the 1% and the 0.2% annual chance floods. FEMA’s other label for this area is Zone B. | Outside the SFHA: a policy is optional. |
| X, unshaded | Minimal hazard: outside the 0.2% annual chance flood. FEMA’s other label for this area is Zone C. | Outside the SFHA: a policy is optional. |
| X, levee | FEMA marks this area as reduced flood risk due to a levee. | Outside the SFHA: a policy is optional. |
| D | Possible but undetermined flood hazard. FEMA has done no analysis here. | Undetermined: no FEMA analysis to read. |
| No zone returned | FEMA has no flood polygon at this point. The area may be unmapped, or mapped only on paper panels outside the National Flood Hazard Layer. | Not Zone X, and not a finding of low flood risk. |
The zone is read live from FEMA’s National Flood Hazard Layer at the address point, with FEMA’s own subtype, and each answer links the exact query. A lot can straddle zones. The floodway, AH, AO, levee and D rows are the NFHL values as the check returns them; the FEMA pages in the source line define A, AE, V, VE and X.
Two flood findings cap the Score.
Flood is one of the Score’s nine factors. Two flood findings go further and set a ceiling on the Score, whatever the other factors say.
- Floodway · cap 25
- Part of the parcel lies in a regulatory floodway, the hardest flood constraint (see the zone codes above).
- Over half the lot in an SFHA · cap 60
- Building is usually possible with an elevated design, but expect flood insurance, an elevation certificate and floodplain-development permitting to stack cost onto the build.
The lot’s share in an SFHA is sampled across the parcel when the county outline matches. A floodway takes the place of the 60 cap, not both.
SourceFEMA NFHL, zone subtype and parcel sampling·How the Score caps a lot
A LOMA changes the designation, not the map.
FEMA amends a designation by letter when a structure or parcel sits above the base flood. The effective maps and the letters already issued are at the Map Service Center.
- LOMA
- Letter of Map Amendment: a structure or parcel on natural high ground that the base flood would not reach.
- LOMR-F
- Letter of Map Revision based on Fill: a structure or parcel raised above the base flood with fill.
The request goes to FEMA with elevation data. Fees and processing time are not on record here.
Questions
The zones
What do FEMA flood zone codes mean for building?
Zones A, AE, V and VE are Special Flood Hazard Areas, flooded by the 1% annual chance flood; X is outside them. The zone codes table above gives each one, and what it means for insurance.
What if FEMA returns no zone for my address?
The area may be unmapped, or mapped only on paper panels outside the National Flood Hazard Layer. That is not Zone X, and not a finding of low risk. Check the effective map at msc.fema.gov or ask the local floodplain administrator.
Is the zone for the whole lot?
No. The zone is read at the address point, and a lot can straddle zones. When the county outline matches, the check also samples the lot for its share in an SFHA, and over half caps the Score at 60. A survey or an elevation certificate settles where the flood line crosses a lot.
What is the difference between a 100-year and a 500-year flood zone?
The 100-year flood that maps Zones A, AE, V and VE has a 1% annual chance. Over a 30-year mortgage that compounds to about 26% (1 − 0.9930), the figure FEMA gives for Zone VE. The 500-year flood is the 0.2% annual chance limit that bounds Zone X (shaded).
SourceFEMA, Flood Zones (glossary), fema.gov/about/glossary/flood-zones, read 2026-10-19·FEMA, Zone VE and V1-30 (glossary), fema.gov/glossary/zone-ve-and-v1-30, read 2026-10-19
Insurance and the map
Is flood insurance required for my mortgage?
A Special Flood Hazard Area (Zone A, AE, V or VE) is where FEMA says the mandatory purchase of flood insurance applies, and where the NFIP floodplain rules must be enforced. Outside one, a policy is optional.
How much does flood insurance cost?
The zone does not set the price. Under Risk Rating 2.0, FEMA prices each building on its own flood risk, so get a quote from an agent. The zone decides whether the mandatory purchase of a policy applies.
Can I get my property out of a flood zone?
FEMA issues a Letter of Map Amendment (LOMA) when a structure or parcel on natural high ground would not be flooded by the base flood, or a LOMR-F when it was raised with fill. The request goes to FEMA with elevation data. A letter changes the designation, not the map. Fees and processing time are not on record here.
Is this flood data current?
Buildability reads FEMA’s National Flood Hazard Layer when the report is run, and the time of the read is shown with the answer, with its date when it was not today: a repeat lookup can come from a report cached for up to 7 days. FEMA revises maps community by community. Pending revisions are listed at msc.fema.gov; confirm with the local floodplain administrator before you decide.
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Flood is one of nine factors. See all nine (zoning, flood, seismic, soil, radon, wildfire, utilities, terrain, and lot geometry) for any U.S. address, in 20 seconds.
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