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Lowest Floor

The purpose of this page is to define the lowest floor, a commonly used term in floodplain management.


The lowest floor of the lowest enclosed area (including basement). An unfinished or flood resistant enclosure, usable solely for parking of vehicles, building access or storage in an area other than a basement area is not considered a building's lowest floor; Provided, that such enclosure is not built so as to render the structure in violation of the applicable non-elevation design requirements of Sec. 60.3.
Communities are required to obtain the elevation of the lowest floor (including basement) of all new and substantially improved structures.

All new and substantially improved structures must have the lowest floor elevated to or above the Base Flood Elevation (BFE). Non-residential buildings may be floodproofed below the BFE.

National Flood Insurance Program (NFIP) Requirement

Other Applicable NFIP Regulations

  • 60.3 - Floodplain management criteria for floodprone areas
    • (c) (2) - Zone A Residential Buildings
    • (c) (3) - Zone A Nonresidential Buildings
    • (c) (5) - Openings
    • (c) (6) - Manufactured Homes
    • (c) (7) - Zone AO Residential Buildings
    • (c) (8) - Zone AO Nonresidential Buildings
    • (c) (12) - Manufactured Homes


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Last Updated: 
01/27/2020 - 10:35