Special Flood Hazard Area Requirements

This page provides a guide for all new residential, commercial, additions and shell construction projects. Following these guidelines will help ensure the application, plans and supporting documentation are complete and sufficient for permit submittal which will ensure a timely review and response.

Special Flood Hazard Area (SFHA)

All properties located within the Special Flood Hazard Area (SFHA) shall have full compliance with the requirements of the Hillsborough County Construction Code, Hillsborough County Land Development Code, ASCE 24, the Florida Building Code and all other applicable laws and regulations that govern the standards set forth within the National Flood Insurance Program; most restrictive shall apply.  

Verify the applicable zoning district, flood hazard areas and Base Flood Elevation(s) (BFEs) on the Hillsborough County Flood Zone Viewer and FEMA Flood Map Service Center (MSC). Parcel details can also be obtained from the Hillsborough County Property Appraiser website. 

If the property is located within a Coastal High Hazard Area (Zone V) and Coastal A Zone or areas known to have muck soils, highly organic suspect soils, or where there is erosion, scour or settling of underlying soils on the property; more information may be required to ensure the project meets the applicable code requirements for all development within these areas. 

Note: A soils and foundation analysis (geotechnical report) may be required to be provided by a Florida Registered Engineer that shows supporting information and a recommendation for the foundation design of the proposed structure.

Elevation certificate requirements

The applicant shall submit an Elevation Certificate (FEMA Form FF-206-FY-22-152) marked “Construction Drawings” with the building permit application. 

In lieu of the Construction Drawings Elevation Certificate, the applicant shall submit a signed and sealed site plan with the effective flood zone boundary and flood elevations indicated. This Elevation Certificate OR Signed and Sealed site plan shall be used to determine if the proposed design is in compliance with the Florida Building Code (FBC), the Hillsborough Country Construction Code (HCCC), and the Flood Damage Control Regulations (PART 3.06.00 of the Land Development Code).

After the foundation is built and the elevation of the lowest floor is determined, another Elevation Certificate shall be submitted that is marked “Building Under Construction”.

In lieu of the “Building Under Construction” Elevation Certificate, a signed and sealed Foundation Tie-In Survey indicating the lowest floor shall be located at the job site indicating the as-built floor elevation. This will document the elevation of surrounding grades and the lowest floor to ensure they comply with the approved plans before further construction is allowed.

Once construction on the building is finished (including electrical and mechanical) and all adjacent grading is finalized, a complete and correct “Finished Construction” Elevation Certificate must be submitted indicating the as-built characteristics of the building. A “Finished Construction” Elevation Certificate must be received, reviewed, and corrected (if necessary) before a Certificate of Occupancy is issued. 

Substantial improvement or substantial damage to existing structures 

Substantial Improvement Worksheets are required for all projects within the SFHA and shall comply with all applicable flood hazard reduction provisions; any alteration, repair, additions, reconstruction or improvements to a building shall have the Worksheets completed and uploaded with the construction plans for review and recording with the permit application -OR- an approved FEMA Elevation Certificate submitted by the applicant which documents the building is properly elevated and conforms to flood resistant construction requirements.

Elevated Structures within SFHAs 

Enclosed areas, including crawlspaces, that are below the Base Flood Elevation shall be used solely for parking of vehicles, building access or storage. Where the lowest floor is six (6) feet or higher above the final lowest adjacent grade, the enclosed area below the lowest floor shall not be partitioned, finished into separate rooms or temperature controlled. 

All enclosures below elevated structures must be designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of floodwaters. Hydrostatic Flood Vents and flood resistant materials must be installed in compliance as per applicable code. 

• A Nonconversion Affidavit/Attestation signed by the property owner shall be submitted to the permit file to acknowledge the prohibition of the conversion, agreeing not to convert or modify in any manner that is inconsistent with the terms of the building's originally approved design and floodplain regulations.

Construction within the regulatory floodway

When floodways are designated within the SFHA on the Flood Insurance Rate Map (FIRM) or within the Flood Insurance Study (FIS), additional criteria will be met. Since the floodway is an extremely hazardous area due to the velocity of flood waters which carry debris, potential projectiles, and erosion potential, notwithstanding any of the above, the following provisions shall apply:

• Any encroachment or placement of an obstruction is prohibited, including fill, any new construction, substantial improvements, mounded septic systems, docks, and other development unless it has been demonstrated through a no-impact analysis (hydrologic and hydraulic analyses that are also referred to as a No Rise Impact Analysis) with supporting technical data submitted by a State of Florida Registered Engineer demonstrating that the proposed encroachment shall not result in any increase in flood levels within the community during the occurrence of the base flood discharge. Background and analyses details shall be provided pursuant to the Federal Emergency Management Agency bulletins provided for said process. All new construction shall comply with all applicable flood hazard reduction provisions per the HC-LDC and those within the HCCC.
• The placement, or replacement, of any manufactured home, except in a pre-FIRM manufactured home park or subdivision that has not had a manufactured home flooded, is prohibited within the designated floodway.

Buildings and structures located in whole or in part in identified floodways shall be designed and constructed in accordance with ASCE 24 and all applicable code requirements.

Design and certification of dry floodproofing  

The Floodproofing Certificate is for a building that has a commercial or other nonresidential use. The Floodproofing Certificate (FEMA form FF-206-FY-22-153), must be prepared by a registered professional engineer or architect, certifying that the design and methods of construction of the nonresidential building are in accordance with the accepted practices for meeting the floodproofing requirements. 

Definitions 

• Appraised value: appraised value is defined as either (1) one hundred and twenty percent (120%) of the assessed value of the structure as indicated by the County Property Appraiser’s Office or (2) the value as indicated in a certified uniform 3 of 10 01/2021 Substantial Damage/Improvement Guidelines appraisal report based upon comparable sales, which is not a limited-summary appraisal report. For floodplain management purposes, the appraised market value is based on the County Property Appraiser’s assessed structure value or the commercially appraised depreciated structure value. When used for the purposes of determining substantial improvement, it pertains only to the value of the structure. It does not pertain to the land, landscaping, detached accessory structures, or other site improvements (for example, docks, seawalls, and gazebos). (Reference; HCCC Chapter 4 Definitions) 
• Design Flood Elevation: the elevation of the “design flood,” including wave height, relative to the datum specified on the community’s legally designated flood hazard map. In areas designated as Zone AO, the design flood elevation shall be the elevation of the highest existing grade of the building’s perimeter plus the depth number (in feet) specified on the flood hazard map. In areas designated as Zone AO where the depth number is not specified on the map, the depth number shall be taken as being equal to 2 feet. (Reference; HCCC Chapter 4 Definitions)
• Dry Floodproofing: includes measures that make a structure watertight below the level that needs flood protection to prevent floodwaters from entering. This type of floodproofing is often used to protect non-residential structures, water supplies, and sewage systems.
• Flood Insurance Rate Map (FIRM) effective date: the date on which Flood Insurance Rate Maps were made effective for unincorporated Hillsborough County is June 18, 1980. (Reference; HCCC Chapter 4 Definitions) 
• Market value: the term refers to the market value of buildings and structures, excluding the land and other improvements on the parcel. Market value may be established by a qualified independent appraiser, Actual Cash Value (replacement cost depreciated for age and quality of construction), or one hundred and twenty percent (120%) of the tax assessment value as indicated by the County Property Appraiser’s Office. (Reference; HCCC Chapter 4 Definitions) 
• Pre-FIRM construction: for floodplain management purposes, is associated with structures for which the “start of construction” commenced before June 18, 1980 (unincorporated Hillsborough County effective date of the Flood Insurance Rate Map(s). This term may also be referred to as “existing structures”. (Reference; HCCC Chapter 4 Definitions) 
• Substantial improvement (SI): as defined in Title 44 of the Code of Federal Regulations § 59.1, means any reconstruction, rehabilitation, addition or other improvement of a structure, the cost of which equals or exceeds 50 percent of the market value of the structure before the “start of construction” of the improvement. This term includes structures that have incurred “substantial damage,” regardless of the actual repair work performed. The term does not include either: 
• Any project for improvement of a structure to correct existing violations of state or local health, sanitary, or safety code specifications which have been identified by the local code enforcement official and which are the minimum necessary to ensure safe living conditions or 
• Any alteration of a “historic structure”, provided that the alteration will not preclude the structure’s continued designation as a “historic structure”. 
• Substantial damage (SD): as defined in Title 44 of the Code of Federal Regulations § 59.1, means damage of any origin sustained by a structure whereby the cost of restoring the structure to its before damaged condition would equal or exceed 50 percent of the market value of the structure before the damage occurred. 
• Wet Floodproofing: a structure that modifies the uninhabited portions (such as a crawlspace or an unfinished basement) to allow floodwaters to enter and exit. This ensures equal hydrostatic pressure on the interior and exterior of the structure and its supports. Equalized pressures will reduce the likelihood of wall failures and structural damage. Wet floodproofing is practical in only a limited number of situations. 

Additional resources

For Building and Construction Services assistance, please contact permitting@hcfl.gov.