FEMA Flood Zones Explained: Every Zone Code

Last updated 2026-10-21 · MapElevation

FEMA flood zone codes at a glance

A zone code is a compact label attached to mapped information. It helps identify the type of flood hazard studied and whether certain elevation information is shown. It does not replace the map legend, study, or a reliable building position. Start with flood zone by address, then use the sections below to interpret the returned label. The FEMA training glossary provides official definitions for these categories.

The table is a navigation aid, not a property-specific insurance decision. The NFIP’s official flood-zone and insurance guidance explains the mandatory-purchase context for buildings in high-risk areas with relevant federally backed lending. A lender can also have requirements beyond the minimum rule. Verify your own loan, building location, and effective map with the responsible parties.

How to use this page

1. Find the returned code and subtype in the comparison table.
2. Read its anchored explanation and the effective map’s legend.
3. Follow the X or AE detail page when that category applies.
4. Confirm building-specific requirements with the responsible community, lender, or professional.

Riverine high-risk zones

Zone A

Zone A identifies a special flood hazard generally studied with approximate methods rather than a detailed BFE analysis shown on the map. That absence should lead to another information request, not a guess at a water elevation. Ask the local floodplain manager which study or other accepted source is relevant to a proposed activity. For a map amendment question, explain that the location is in an approximate-study area before hiring someone to collect measurements, so the professional can determine what additional information is needed. The BFE lookup guide explains why a blank field cannot be replaced with terrain height. Confirm the source before requesting any numerical comparison.

Zone AE and older A1–A30 labels

Zone AE is associated with detailed-study flood information and BFEs. The existence of a BFE does not tell you the elevation of a building, and the relevant value still needs to be read in its map or study context. Do not assume that one returned static attribute is a complete engineering determination at every point in a polygon. Older numbered A zones may appear in historic records; retain the map version when comparing them with a current designation. The Flood Zone AE meaning page covers datum questions, insurance context, and potential next steps in more detail than this summary. Check the underlying study before comparing measurements.

Zone AH

Zone AH relates to shallow flooding, typically ponding, with BFE information shown through the detailed study. It should not be interpreted as a generic version of AE without attention to the mapped flood mechanism. Ponding can behave differently from water moving through a well-defined channel, and the local floodplain manager is the appropriate starting point for questions about construction or mitigation requirements. A surface elevation near a building cannot establish the design conditions for that building. Keep the code and study information together, request the effective map, and use certified elevation records where the intended decision requires them. The elevation certificate guide explains those records.

Zone AO

Zone AO describes shallow flooding for which the map can provide depth information rather than the same form of BFE expected in a detailed riverine study. A depth and an elevation are different quantities: one describes water above a relevant surface, while the other needs a vertical reference. Do not enter a mapped depth into a field labelled BFE or add it to an unrelated terrain pixel. For an application, ask which grade definition, depth information, and local standards apply. Retain the original map labels when communicating with the community or surveyor so that an apparently simple unit conversion does not conceal a change in meaning.

Zone AR

Zone AR involves a flood-protection restoration context and requires reading the specific effective mapping and applicable information. A short code cannot explain the status of a protection system, the work involved, or the requirements that apply to a particular building. Avoid treating the label as evidence that protection is complete or that flooding cannot occur while work is under way. When evaluating a property, ask the community floodplain manager for the current study and project context, and keep that answer separate from a general terrain lookup. FEMA’s zone definitions should be used with the effective map rather than with an old screenshot alone.

Zone A99

Zone A99 is associated with a qualifying flood-protection system under construction. Its designation reflects specified progress conditions; it does not mean that every relevant protective feature is complete or that a homeowner can ignore current requirements. A99 also should not be used as a substitute for the actual BFE or local construction guidance. Request the effective mapping, the relevant protection-system information, and the community’s explanation of how the designation affects the activity you are considering. When asking for an insurance or lending decision, give the responsible professional the current documents. A model of surface heights cannot establish the project’s legal status or completion conditions.

Coastal high-risk zones

Zone V

Zone V identifies coastal high-hazard conditions generally mapped without the detailed BFE information associated with VE. The coastal setting adds wave-related considerations that are not represented by an ordinary surface elevation. A point that appears relatively high on a global terrain map can still require careful interpretation of the coastal study and building requirements. Ask for the effective map and associated study material, and discuss a property-specific question with the community and a qualified professional. The sea level rise map is a separate illustrative scenario tool; it does not recreate a FEMA coastal hazard study or replace coastal design information.

Zone VE and older V1–V30 labels

Zone VE combines coastal high-hazard mapping with detailed BFE information. The water elevation alone does not capture every condition relevant to coastal buildings. Do not assume that standing above a displayed number resolves wave, erosion, foundation, or other design questions. Historic numbered V labels can appear in earlier records; compare dates and legends before treating them as the same map as the current one. The official coastal study and the building’s own records should guide the next information request. If you have a certificate, use the elevation certificate guide to identify the relevant fields and ask the preparer how they relate to the effective coastal map.

Shaded and unshaded Zone X

Shaded Zone X

Shaded X is often associated with moderate mapped flood hazard, but its complete interpretation depends on the subtype and map legend. The official legend can describe the 0.2-percent annual-chance flood area as well as other specified conditions; do not reduce every shaded feature to a single generic probability. FEMA’s map-reading material distinguishes moderate and minimal areas. Read the Flood Zone X meaning guide before interpreting an X result. In particular, a short code returned without its subtype is incomplete context, and being outside the SFHA is not a declaration that all flood mechanisms have been assessed or eliminated. Retain the exact subtype in your own notes.

Unshaded Zone X

Unshaded X denotes minimal mapped flood hazard in the relevant map context. “Minimal” is not a guarantee, and the boundary reflects the scope and methods of the effective study. A property can still face drainage or other flooding that a casual reading of the designation overlooks. Check the source map, nearby features, and any information held by the community. If a result will affect coverage, obtain an insurer’s advice rather than inferring a price or a recommendation from the map color. The tool provides the designation as information for that discussion, not a statement that a homeowner should cancel protection or ignore future map changes.

Zone D and older map labels

Zone D

Zone D means the flood hazard is undetermined, not that the flood hazard is absent. This distinction is particularly important when comparing properties: a location with less mapped information should not automatically appear preferable to a location studied in detail. Ask what data exists, which local requirements apply, and whether further study is needed for the proposed decision. A terrain model can describe broad landform context but cannot fill the gap in flood-hazard analysis. Preserve the unknown status in any notes you share. If the website returns no FEMA feature at all, that is also different from an actual mapped Zone D feature and should be labelled separately.

Older Zone B and Zone C labels

Older FIRMs can use B for moderate and C for minimal mapped hazard, where newer maps commonly use shaded and unshaded X. Read the original legend before translating a label, and record which document you are discussing. A historic designation does not establish the current effective zone because studies, boundaries, and later map-change documents may differ. When collecting records from a previous owner, retain the full panel and date rather than copying just the letters into a new report. Use the FEMA Map Service Center to establish the current mapping context and ask the community how any older document should be interpreted.

How zone codes relate to BFE and insurance

A code, a published BFE, an insurance premium, and a building elevation are related but distinct pieces of information. FEMA’s Risk Rating 2.0 fact sheet explains property-specific pricing. A code alone cannot produce a quote. For a possible amendment, start with the LOMA flood guide and collect the relevant measured and mapped evidence rather than comparing a global surface pixel with an unexplained flood number.