Key Biscayne homeowners relying on federal flood maps to gauge their risk may be looking at data from 2009.

Miami-Dade County's official FEMA Flood Insurance Rate Maps have not been updated since Sept. 11, 2009, according to the county's floodplain management office. FEMA released preliminary replacement maps in 2021, and a 90-day public appeal period closed March 1, 2022, but the county has not announced when the new maps will take effect. That leaves the island's barrier-island properties in limbo.

The stakes are rising. Key Biscayne voters will decide Nov. 3 whether to approve a general obligation bond for stormwater and flood prevention projects exceeding $50 million. The Village Council reviewed ballot wording at a special meeting July 7. The proposed 2026 fiscal year budget of $44.5 million is driven by flood control and public safety, Islander News reported June 30.

10 million high-risk properties sit outside FEMA's maps

A First Street Foundation analysis published Wednesday estimates that roughly 10 million high-risk flood properties nationwide sit outside FEMA's official Special Flood Hazard Areas. The research group pegs the true number of properties facing at least a 1% annual flood chance at 17.7 million, more than double FEMA's official count of 7.9 million. Eighty-four percent of the agency's maps are more than five years old.

Florida statewide added 77,000 properties in high-risk flood areas between 2019 and 2023, and more than half were built outside FEMA's mapped boundaries, according to First Street Foundation data. Those homes bypassed mandatory flood insurance and stricter building-code requirements.

Florida's maps are updating county by county with no single statewide schedule. Bay County's new maps took effect Aug. 16, 2024. Lee County's coastal maps became effective Nov. 17, 2022. Collier County's updates have no fixed date. Miami-Dade is still waiting.

A new map could trigger mandatory insurance

Once an updated FEMA map becomes effective, homeowners with federally backed mortgages whose property lands in a newly designated Special Flood Hazard Area must purchase flood insurance. The trigger is the map's effective date, not the release of a draft or preliminary version.

"If you haven't gotten a letter about flood risk, that isn't necessarily good news," an Insurify analysis published July 15 states. "It may be that no one has yet redrawn your county's map."

Florida policyholders already carrying flood insurance have seen premiums jump an average of 50% under FEMA's Risk Rating 2.0 system, which replaced flat zone-based pricing with individualized property-level rates between 2021 and 2023, according to Insurance Journal's August 2025 reporting. A Federal Reserve Bank of Philadelphia study the same year calculated that 70% of annual flood losses go uninsured, totaling $17.1 billion in exposure nationwide.

Village presses ahead on flood spending without FEMA

Key Biscayne has been spending on flood resilience while the federal maps remain frozen. At its Nov. 18, 2025, meeting, the council authorized $373,646 to Black & Veatch Corp. for the Resilient Infrastructure and Adaptation Program, prepared by Chief Resilience and Sustainability Officer Roland Samimy. The same meeting approved a Clean Water State Revolving Fund loan for stormwater improvements.

On March 10, Mayor Joe Rasco proclaimed Flood Awareness Week, and Building, Zoning and Planning Director Jeremy Calleros Gauger delivered a Community Rating System report to the council. On June 18, the council approved a land-use agreement with Ocean Club for a flood pump station.

How homeowners can check their flood zone

Homeowners can look up their current and preliminary flood zone designation at FEMA's Flood Map Service Center, msc.fema.gov, by entering their address. Miami-Dade County also maintains an interactive tool showing both the 2009 effective maps and the 2021 preliminary maps side by side.

Property owners who believe their parcel has been incorrectly mapped can submit a Letter of Map Change to FEMA. Miami-Dade County's Flood Zone Hot Line is 305-372-6466.