If you own a home on Treasure Island, you've probably heard neighbors talk about "the 50% rule." After Hurricanes Helene and Milton in 2024, it became the single biggest factor in whether island homes could be repaired or had to be raised or rebuilt. Here's what it means in plain terms.
What the 50% rule says
The rule comes from the National Flood Insurance Program, which FEMA runs. Cities that take part in the program, including Treasure Island and St. Petersburg, have to enforce it. It works like this:
- If your home is in a special flood hazard area (zones that start with A or V on the flood map), and
- the cost to repair it, or the cost of improvements you're making, equals or goes over 50% of the building's market value,
- then the whole building has to be brought up to current flood rules. In most cases that means raising the home above the required flood elevation, or tearing it down and rebuilding.
When the cause is storm damage, it's called substantial damage. When it's a remodel or addition, it's called substantial improvement. The math is the same.
What counts as "value"
The 50% is measured against the value of the building only, not the land. On the islands, land is often worth far more than the house sitting on it, so the building value can be lower than owners expect. Cities usually start from the county property appraiser's building value. Some let you submit a private appraisal of the structure if you think that number is too low.
What counts as "cost"
The repair or improvement cost generally includes the full market cost of the work, including labor, even if you or a friend do it yourself. Some items, like plans, permits, and survey fees, are often left out. After the 2024 storms, Treasure Island used cost estimates based on FEMA's tool and local market rates to make its damage determinations, and owners who disagreed could appeal.
Rules change. Each city sets its own details, like whether improvements add up over several years and how appeals work. Always confirm the current rules with the City of Treasure Island or St. Petersburg building department before you plan a big project.
How to plan around it
- Find your flood zone and building value. Look up your property on the Pinellas County Property Appraiser site and the FEMA flood map.
- Get a detailed, itemized estimate. A clear scope helps you see how close you are to 50% before any work starts.
- Decide what matters most. Sometimes a smaller repair now keeps you under the threshold. Sometimes it's smarter to raise or rebuild, because a code-compliant elevated home can cost less to insure and hold up better in the next storm.
- Ask about mitigation funding. Flood insurance policies may include Increased Cost of Compliance coverage that can help pay to elevate or rebuild a substantially damaged home. Ask your flood insurance agent.
Repair, raise, or rebuild?
There's no single right answer. A home that's well under the threshold can often be repaired and updated. A home that's over it has to come into compliance, and at that point many owners find a new elevated home makes more sense than raising an older one. We walk Treasure Island and St. Pete homeowners through both paths and give you real numbers for each.
If you're weighing your options, ask us for a free estimate or learn more about our work on Treasure Island.