Thousands of Florida homes flood repeatedly. You’re not allowed to know which ones.

Between “rain bombs” and drenching from no-name storms, hundreds of homes in South Florida have experienced damaging flooding in the last year alone. But an exact count of flood-prone homes in South Florida — and where and how often they flood — has been all but impossible to pin down.

Newly released data from the Federal Emergency Management Agency puts some hard numbers to a problem that climate change promises to make worse in the coming decades. Thousands of homes across the state have endured water damage more than once. It’s a number that is growing across the state, in part because in the vast majority of cases, little has been done to protect the properties from future floods.

Here’s the kicker: Potential buyers and renters are prohibited from knowing that flooding history under federal and state rules. And those FEMA numbers are almost assuredly an undercount of flood-prone properties because the agency’s data reflects only insured properties that filed flood claims with the National Flood Insurance Program. Plenty of homeowners are not required to hold flood insurance policies or use a private company that doesn’t report claims data.

“These are the tip of the iceberg when it comes to repeatedly flooded properties in the US,” said Anna Weber, a senior policy analyst at the Natural Resources Defense Council, which analyzed the FEMA data.

The FEMA data in question, released by the NRCD on Tuesday, is just part of the flood damage picture, showing only what the federal government declares as a “severe repetitive loss property.” That designation covers homes that have flooded twice, with damage totaling the value of the property, or flooded four times with at least $5,000 of damage each time.