Flooding has caused $55 billion a year in damage in the United States, measured in 2025 dollars, on average over the decade ending in 2024, the Congressional Budget Office says in a report released Oct. 6. The figure arrives as Hurricane Isaias nears the northern Gulf Coast with a forecast of 5 to 7 feet of storm surge in places.
The report, How Spending for Flood Adaptations Affects the Federal Budget, was written by CBO analyst Chad Shirley with guidance from Joseph Kile. It starts from a plain statement: “Flooding is among the costliest natural disasters in the United States.” Its subject is what federal spending on prevention buys, and who ends up paying when it does not.
The answer for most of that $55 billion is not an insurer. National Flood Insurance Program claims averaged $4.4 billion a year from 2015 through 2024, about 8% of flood damage, and most properties at risk of flooding are not covered by NFIP policies, according to the full report. Federal relief for hurricanes from 2000 through 2019 averaged about 45% of damage, and the rest fell on households, businesses and state and local governments. For a homeowner on the Gulf Coast, the gap between what the water destroys and what a policy or Congress pays is the household’s own money.
Isaias is forecast to reach the northern Gulf Coast late Friday or early Saturday, the next date that puts these flood-loss figures to work.
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A federal flood insurer $23 billion in debt
The NFIP, which the Federal Emergency Management Agency runs, owed the Treasury $23 billion as of March 2026, after $16 billion of its debt was forgiven in 2017. It has about 4.5 million policyholders and collected roughly $5 billion a year in premiums and fees from 2023 through 2025. About 22% of its policies were subsidized as of 2023, down from roughly 40% in 1990.
FEMA introduced Risk Rating 2.0 in October 2021 to align premiums more closely with each property’s flood risk, and the subsidies are being phased out. For policyholders, that means premiums are being aligned with each property’s own risk as the discounts shrink.
What a dollar of prevention buys
The report’s central estimate is that each $1 of federal adaptation spending reduces future flood damage by about $3 to $4 over 30 years, in present-value terms. The return differs by agency: about $3 per dollar for Army Corps of Engineers projects and about $2 for FEMA projects. The two agencies spent roughly $2 billion a year on average from 2020 through 2024, in 2025 dollars.
The effect shows up in insurance too. Each $1 billion in adaptation spending would cut expected claims by about $70 per NFIP policyholder over 30 years. CBO adds a budget caveat: its cost estimates do not include future reductions in disaster relief, because those appropriations have not yet been made.
The damage curve through 2050
Climate change alone is projected to raise flood damage by about one-quarter to one-third in real terms by 2050, and CBO says development could add as much or more. Congress has leaned on supplemental appropriations to pay for disaster relief, which totaled more than $20 billion a year on average for FEMA and the Army Corps from 2005 through 2024. Because relief is mostly discretionary rather than automatic, the share of a given disaster that Washington covers can differ from one storm to the next.
The storm that tests the numbers
The National Hurricane Center’s Advisory 10, issued at 10 p.m. CDT Thursday, lists Isaias as a hurricane with 105 mph winds and a landfall forecast for late Friday or early Saturday. Surge of 5 to 7 feet is forecast from Dauphin Island, Alabama, to Indian Pass, Florida, and 4 to 6 feet from Indian Pass to the Steinhatchee River and across Mobile Bay and the Mississippi coast to Dauphin Island.
Rain is the second flood driver. Southern Alabama, the Florida Panhandle, the Big Bend and southwest Georgia are forecast to receive 4 to 8 inches, with localized totals up to 15 inches, and the coastal Carolinas 3 to 5 inches.
Checking flood exposure before the water arrives
The CBO report is the best free reference for how the system works, and it is public in full. Its landing page links the PDF and a data spreadsheet with the underlying tables. Anyone deciding what to do about a flood-prone home can start with two questions that follow from the report: whether the property has a flood policy at all, and what that policy’s premium would be under Risk Rating 2.0 rather than the old subsidized rate.
Ask the insurer or agent for the declarations page of any flood policy and for the building and contents limits, and keep a copy where it can be reached without power or internet. For homes with no flood policy, the report’s 8% insured share is the point of comparison: about 92% of flood damage in the CBO’s decade average was paid by someone other than the flood insurance program.
The CBO numbers are averages over a decade, not a forecast for Isaias. The report’s own anchor is the one to keep in mind: $55 billion a year in damage, of which about $4.4 billion a year was paid by the NFIP.
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This article was produced with AI assistance and reviewed by The Financial Wire’s editorial team.
David M. Keller is a finance writer based in Columbus, Ohio, covering personal finance and consumer-focused economic topics. He earned his degree in journalism from Ohio University and began his career reporting on local business and economic trends for a regional media outlet. Since then, he has contributed to a variety of online publications, focusing on clear, practical coverage of topics such as cost of living, debt, and everyday financial decision-making.
