That 'Extreme' Flood Score on a Florida Listing Isn't Your Flood Zone. Florida Just Sued the Company Behind It.

If you’re house hunting in Florida and a listing flashes an “Extreme” flood score, don’t walk away yet. If you’re selling a house that got tagged with one, you’re not stuck with it.

That 1-to-10 number isn’t your FEMA flood zone. It isn’t what the federal flood program uses to price your policy either. And on October 23, Florida’s attorney general sued the company that makes it.

Where the score comes from

The score is First Street’s Flood Factor. According to Florida’s complaint, First Street started as a nonprofit, turned into a venture-backed company, and was bought by MSCI for $120 million in August 2026. Its scores have shown up on listings at Redfin, Realtor.com and Zillow. Zillow pulled First Street’s direct data in December 2025 after complaints from the California Regional Multiple Listing Service, the complaint says, but still points shoppers to it.

Attorney General James Uthmeier filed under Florida’s deceptive trade practices law. The complaint calls it “climate chicanery.” Its sharpest exhibit is a homeowner’s Better Business Bureau complaint: a 10/10 “Extreme” score, with the neighbors on both sides rated 1/10 “Minimal,” on a property that “has never flooded, and FEMA flood maps reflect this.”

Here’s the part the listing doesn’t tell you. First Street’s own help page, as quoted in the complaint, says “as a rule, we do not update Factor scores based on individual … disputes.” You can pay for a full report and enter better details about your house. Per the complaint, that still won’t change the public score every buyer sees.

Nebraska’s attorney general filed a similar suit in August. First Street hadn’t answered requests for comment from HousingWire or the Florida Phoenix. This is a lawsuit, not a ruling.

Why it costs you either way

Zillow’s own 2025 research, cited in the complaint, found 52% of homes with a high flood-risk score sold, against 71% with a low one. A scary number can cost a seller a buyer. A falsely calm number can cost a buyer a house.

Verdict: questionable. A private guess with no fix button shouldn’t decide a six-figure purchase. Neither should no information at all.

The numbers that move your money are elsewhere. FEMA’s flood zone decides whether flood insurance is required: in high-risk zones like A and V, it’s mandatory for federally backed mortgages. And an NFIP premium is “unique to your property,” priced off distance to flooding sources, ground elevation, foundation type and first floor height. A listing score isn’t on that list.

What to do before you sign

Buying? Get a real NFIP quote from an insurance agent before your inspection period ends, and put it into our mortgage calculator next to taxes and homeowners insurance. Read the seller’s flood disclosure. Florida law requires it at or before contract, and it says whether the seller knows of flood damage during their ownership, filed a flood claim, or got FEMA aid. Ask for an elevation certificate if one exists. Our first-time buyer guide covers the rest of the paperwork.

Selling? Don’t wait for First Street to fix your score. Answer it. Post the FEMA flood map and your elevation certificate with the listing. The complaint cites owners who say they couldn’t sell until they did exactly that. Keep your flood policy’s declarations page handy too. A real premium beats a scary scale.

The same disclosure form opens with a line worth taping to the fridge: “Homeowners’ insurance policies do not include coverage for damage resulting from floods.”

How Candid Yak makes money. Some of the products we write about pay us if you apply or sign up through our links. That never changes our verdict, our rankings, or the numbers in this article. We call a bad deal a bad deal whether it pays us or not. Some brands shown in our comparison tools are placeholder examples while we finalize partner agreements, and we label them as such.