Base Flood Elevation (BFE): What It Means and How to Find It
Base Flood Elevation, or BFE, is the elevation that floodwater is expected to reach during a flood with a 1% chance of being equaled or exceeded in any given year. You may also hear this event called the base flood or the “100-year flood,” but that name does not mean it happens only once every 100 years.
FEMA shows BFEs on Flood Insurance Rate Maps for many high-risk flood zones. A BFE helps communities apply floodplain-management and building requirements and helps property owners understand how a building’s elevation relates to the mapped flood hazard.
But why does my BFE matter?
Flood maps and flood zones help lenders determine when the federal mandatory-purchase requirement applies, and they help communities manage development in flood-prone areas. BFE is one part of that map and building-compliance picture, but BFE alone does not determine whether a property owner must buy flood insurance.
Your lender, the property’s mapped flood zone, the type of loan, and any applicable map-change determination can all matter. A lender may also require flood insurance even when federal law does not.
How does the Base Flood Elevation (BFE) impact my flood insurance premiums?
Under FEMA’s Risk Rating 2.0 pricing approach, NFIP premiums are based on multiple property-specific and flood-risk variables. FEMA considers factors such as flood frequency, different flood types, distance to a water source, elevation, and the cost to rebuild. A flood zone or BFE may provide useful context, but neither one by itself determines an NFIP premium.
Private flood insurance uses each insurer’s own eligibility, underwriting, coverage, and pricing rules. The meaningful comparison depends on the specific property, coverage needs, lender requirements, and the NFIP and private options available for that address.
How do I find the Base flood elevation for my property?
Start with FEMA’s Flood Map Service Center, the official source for Flood Insurance Rate Maps and related flood-hazard products.
- Enter the property address and open the effective map panel.
- Confirm the flood zone and look for a labeled BFE or base-flood depth.
- Check the Flood Insurance Study when the map refers to profiles or tables for additional elevation information.
- Ask the local floodplain official to confirm which map, datum, and local requirements apply before using the information for construction or compliance decisions.
Some unnumbered Zone A areas do not have a published BFE. In those cases, the community may have other flood data, or a licensed surveyor or engineer may need to develop or document site-specific elevation information. A flood-insurance quote or flood-zone determination should not be presented as a substitute for that work.
Base flood elevation example
The illustration below showcases each of the BFE’s distinctly. For level terrain, it may be necessary to meticulously search the flood map to pinpoint the identifiable BFE.
How high do I have to build above the base flood elevation map?
There is no single “two feet above BFE” rule for every property. Required elevation and freeboard can vary by flood zone, building type, project, state, and community. Local or state standards may be higher than the NFIP minimum.
Before building, renovating, or elevating a structure, ask the local floodplain official which ordinance and map information apply. A qualified surveyor, engineer, architect, or other design professional can help document elevations and design the project to the applicable requirements.
What if I have a property without a base flood elevation Zone A, Unnumbered A flood zone
An unnumbered Zone A is a high-risk Special Flood Hazard Area where FEMA’s effective map does not show a BFE. The local floodplain official may have community flood data or may require a BFE to be developed for a proposed project. A licensed surveyor or engineer can help when site-specific elevation information is needed.
An Elevation Certificate documents map, building, and elevation information for specific floodplain-management, insurance, or map-change uses. Section E is limited to Zone AO, Zone AR/AO, and Zone A without a BFE. Depending on the zone and intended use, an owner or authorized representative may be able to complete the applicable non-survey portions. Other zones and uses may require surveyed elevations, professional certification, or different sections of the form. A map-change request also has separate FEMA application and certification requirements.
Before completing or ordering an Elevation Certificate, confirm what the community, lender, insurer, or FEMA process actually requires.