Jacksonville Beach, FL Environmental Rules: Flood Elevation Requirements (2026)

Where a flood hazard area is delineated on the FIRM but no base flood elevation has been provided (approximate Zone A), section 34-772(a)(5)b directs the floodplain administrator to require the applicant to include base flood elevation data prepared under currently accepted engineering practices, or to obtain and provide data available from a federal or state agency or other source. If no such data exist, the available data do not reasonably reflect flooding conditions, or the data are known to be scientifically or technically incorrect, the administrator can specify that the base flood elevation is three feet above the highest adjacent grade at the development location, provided there is no evidence that flood depths have been or may be greater than three feet. Where the data will support a letter of map change from FEMA, the analyses must be prepared by a Florida licensed engineer or professional surveyor in the format FEMA requires, and the applicant pays the processing fees.

The design flood elevation includes wave height and is measured against the datum on the community's legally designated flood hazard map. In Zone AO it equals the elevation of the highest existing grade of the building perimeter plus the depth number in feet printed on the flood hazard map. If the map prints no depth number for a Zone AO area, the depth number is taken as two feet.

For buildings and structures exempt from the Florida Building Code, the owner must submit the lowest-floor elevation proof. After the lowest floor is placed and before further vertical construction, a certification of elevation sealed by a Florida licensed professional surveyor goes to the floodplain administrator, or, where the three-foot fallback set the elevation, the owner's own documentation of the lowest floor height above the highest adjacent grade. A final certification is due at final inspection. Elevated above-ground tanks must sit at or above the design flood elevation on a supporting structure, and a manufactured home on a pier foundation must have its frame supported by piers not less than thirty-six inches above grade, or meet the Florida Building Code, Residential Section R322.2 or R322.3.