Coastal Flood Risk Map Update

A Flood Insurance Rate Map (FIRM) is an official map on which the Federal Emergency Management Agency (FEMA) identifies areas of high, moderate and low flood risk. Overtime, flood risks change and therefore the flood maps need to be updated. As a result, these mapped changes can have a significant impact on building and flood insurance requirements and costs.

Important Note: Flooding occurs not only in high-risk areas, known as Special Flood Hazard Areas, but also in areas with a low to moderate risk on a FIRM. Anyone can be financially vulnerable to floods. People outside of high-risk areas file over 20 percent of National Flood Insurance Program claims and receive one third of FEMA’s disaster assistance for flooding.

Nationwide Coastal Flood Map Updates

Since the late 2000s, FEMA has been updating Flood Insurance Studies and Flood Insurance Rate Maps for the entire populated coastline of the country to provide improved flood risk information to coastal communities along the Atlantic and Pacific Oceans, the Gulf of Mexico, and the Great Lakes.

The goal of the FEMA National Mapping Program is to deliver quality data that:

  • Increases Public Awareness
  • Leads to Action
  • Reduces Risk


For more information about FEMA’s coastal remapping effort, visit FEMA’s Coastal Flood Risk page

Hillsborough County’s Coastal Flood Map Updates

Hillsborough County’s current coastal study is outdated, using topography data from the 1950s, storm surge and wave height data from the 1980s, and limited detail profiling the coastline. More than 12 major flood-related storms have occurred since the 1980s and there has been extensive development and land alterations since the last study.

The new flood maps will help guide Hillsborough County’s decisions regarding:

  • planning,
  • investment,
  • building,
  • development, and
  • redevelopment


All coastal counties in the Tampa Bay Area are undergoing coastal flood risk map updates. The timeline for Hillsborough County’s update process is outlined below. Dates are subject to change.

  • Discovery, Data Collection, and Stakeholder Coordination – January 2013
  • Modeling – 2013 to 2017
  • Work Map Production – 2018
  • Preliminary Flood Insurance Rate Map (FIRM) and Flood Insurance Studies (FIS) Report – Fall 2018 (expected)
    • FEMA releases preliminary maps to the public
    • More restrictive building requirements take effect in areas showing higher flood risk.
  • Appeal and Compliance Period – early 2019 through Spring/Summer 2019 (expected)
    • FEMA officially notices and begins the formal 90-day appeal and public comment period
    • Scientific and/or technical appeals may be submitted to FEMA by anyone regarding flood zones, floodways, and base flood elevations
    • FEMA issues Letter of Final Determination (LFD). Maps become effective six months from LFD date
    • Hillsborough County will conduct outreach to property owners who may benefit from time-sensitive National Flood Insurance Program (NFIP) flood insurance rating options
    • Official adoption by Hillsborough County Board of County Commissioners for coastal maps and required code changes. If ordinance is not passed by LFD effective date, Hillsborough County will be suspended from the NFIP.
  • Effective FIRM and FIS Report – late 2019/early 2020 (expected)
    • Changes in flood insurance requirements due to flood zone and/or Base Flood Elevation changes become effective
    • Public outreach and stakeholder engagement continues to inform citizens about the changes and insurance rating options available

What to Expect

  • Coastal Flood Maps will be updated for first time since 1981, utilizing better data and tools to more accurately reflect current flood risk
  • Affected number of properties and structures will be estimated following receipt of the preliminary FIRMs (expected Fall 2018)
  • Expect changes to loan requirements and flood insurance costs in areas where updates occur. Some residents and business owners will find that their flood risk has increased, while others it may actually have been reduced. The NFIP has insurance cost-saving rating options to help reduce financial impacts.
  • Revised flood maps will guide Hillsborough County’s planning decisions and development requirements resulting in a more resilient county
  • New FIRMs become effective by early 2020, though County will keep public and stakeholders informed throughout process



Questions about Hillsborough County’s coastal flood risk map process can be directed to Public Works at (813) 635-5400.