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FEMA's National Flood Hazard Layer is the same data behind every flood insurance quote and floodplain building permit in the country. LandCheck draws it and reports the zone under every click. The letters are simple once you know what the agency is actually estimating.
| X (unshaded) | Outside the 0.2% annual chance floodplain. "Minimal" risk on paper. Insurance is optional and usually among the lowest premiums. |
|---|---|
| X (shaded) / 0.2% | The 0.2% annual chance floodplain, shallow 1% flooding under a foot deep or from a very small drainage area, and land behind a levee. Moderate risk; insurance is usually optional, but a lender can still require it. |
| A | 1% annual chance floodplain with no engineered study: no base flood elevation on the map. Common on rural land. Building requires you to establish the elevation yourself. |
| AE | 1% annual chance floodplain with a studied base flood elevation. Lowest floor must sit above it; insurance is required on a federally backed mortgage. |
| AO / AH | Shallow sheet flow or ponding, 1 to 3 feet deep, usually in flat terrain. |
| V / VE | Coastal 1% zone with wave action. Strictest construction rules and usually the highest premiums. |
| Floodway | The channel and the land that must stay open to carry the flood. Building is effectively prohibited. |
| D | Unstudied. Possible but undetermined risk. |
The "100-year flood" is a flood with a 1% chance of happening in any given year. Over a 30-year mortgage that is about a 26% chance of at least one. The maps are also drawn from past studies, some decades old, and they do not model future rainfall or development upstream. A parcel just outside the line is not dry; it is less likely to be wet.
Federal law requires flood insurance on a building in a high-risk zone, any zone that starts with A or V, when the loan comes from a federally regulated or insured lender or is backed by a federal agency, which covers most mortgages (42 U.S.C. § 4012a). A lender can require a policy outside those zones too. Flood insurance covers buildings and their contents, not the land, so a bare lot needs no policy until something is built on it. Outside the high-risk zones a policy is usually optional, and plenty of flood claims come from there, so it is worth a quote on any lot near water.
Since October 2021 for new policies, and April 2022 for renewals, FEMA prices each National Flood Insurance Program policy on that building's own risk instead of mainly on its zone letter (FEMA: Risk Rating 2.0). The rating looks at:
Two houses in the same zone can pay very different premiums, and a house a few feet higher can pay much less. Increases on an existing policy are phased in under yearly caps set by law. The only way to know the price for a building is a quote: an insurance agent can quote an NFIP policy, as many agents who sell home insurance do, and FloodSmart, FEMA's flood insurance site, explains coverage and helps find an agent. Private flood insurers also write policies in many states. For a lot you have not built on, ask an agent for a quote on the house you plan, at the elevation you plan.
An elevation certificate is FEMA's form, filled in by a licensed surveyor, engineer or architect, that records a building's elevations against the base flood elevation. It is optional for most policies under Risk Rating 2.0 but can lower the premium, and the county floodplain manager usually asks for one before and after building in a high-risk zone. For raw land, ask the county whether certificates are on file for nearby houses, and whether a Letter of Map Amendment has taken the lot, or part of it, out of the high-risk zone. If the ground under a building site is naturally above the base flood elevation, FEMA can issue one on request; the federal insurance requirement then no longer applies to that building, though a lender may still ask for a policy.
Open the map with the flood layer on →
What the parcel source shows in each county LandCheck covers: parcel maps by county.
Flood zones on this map are drawn from FEMA's live service and can lag official map changes and letters of map amendment. The county floodplain administrator's determination is the one that counts for permits and insurance.