What Is the 80% Rule in Insurance? And What It Means for a Flood Claim.
The 80% rule decides whether a claim pays to rebuild what you lost or something less. On flood insurance it works a little differently than most people are told — and the NFIP's $250,000 limit counts in your favor.
- Insure your home to at least 80% of its rebuild cost, or the NFIP maximum
- Qualify for replacement cost on a primary single-family home
- Avoid the reduced payout that comes with being underinsured
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One clear recommendation from the NFIP and the private markets that will write your property.
Tip: pick the building coverage closest to what your home would cost to rebuild. We'll check it against the 80% rule before we send your options.
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What is the 80% rule in insurance?
The 80% rule says that to get paid the full cost to repair or rebuild after a loss, your home has to be insured for at least 80% of what it would cost to rebuild it. Insure for less, and the claim is paid on a reduced basis instead.
Two terms matter here. Replacement cost is what it takes to repair or rebuild with similar materials today. Actual cash value is replacement cost minus depreciation for age and wear. The 80% rule is how an insurer decides which of the two you get. It's based on rebuild cost — not your home's market value or what you paid for it.
How the 80% rule works on NFIP flood insurance
On an NFIP policy, a building claim is paid at replacement cost when three things are true:
- It's a single-family home — including a condo unit
- It's your principal residence — where you live most of the year
- Your building coverage is at least 80% of the full replacement cost, or the maximum available — $250,000 for a home
The math when you're below 80%
If your building coverage falls short of 80% (and short of the maximum), the NFIP pays the greater of two amounts: the actual cash value of the damage, or a proportion of the replacement cost — your coverage divided by 80% of the rebuild cost, times the loss. Your deductible comes off after that.
A primary home would cost $300,000 to rebuild, so 80% is $240,000. The owner carries $180,000 of building coverage. A flood does $60,000 of damage. The proportion is $180,000 ÷ $240,000 = 75%, so that method pays $45,000. If the depreciated value of the damage is higher than $45,000, the policy pays that instead. Either way, the owner is short thousands of dollars on a loss that would have been paid in full at $240,000 of coverage.
The fix is usually small: raising building coverage to the 80% line often costs far less than the gap it closes. We price both so you can see the difference.
Who doesn't get replacement cost on the NFIP
Some properties are paid at actual cash value on the NFIP no matter how much coverage you buy. That's worth knowing before you count on a full rebuild.
Can get replacement cost
- A single-family home that's your principal residence
- A condo unit you live in as your principal residence
- Condo association buildings on an RCBAP, insured to the 80% line
Paid at actual cash value
- Second homes and vacation homes
- Rental properties — see rental property flood insurance
- Your belongings (contents) on any NFIP policy
- Most commercial buildings on the NFIP
Condo associations feel the 80% rule hardest: an underinsured master policy triggers a coinsurance penalty on every claim, and unit owners end up paying the difference through assessments. Our RCBAP guide covers that math, and the condo flood insurance page covers what unit owners can do about it.
Private flood policies and the 80% rule
Private flood policies set their own terms. Some offer replacement cost on homes the NFIP would pay at actual cash value, some offer replacement cost on contents, and many offer building limits above $250,000. Some also have their own coinsurance or insurance-to-value clause, which works like the 80% rule with different numbers.
That's why we read the settlement terms, not just the price, when we compare markets. Our private flood vs. NFIP comparison goes deeper.
How to check that you meet the 80% rule
- Find your rebuild cost — from your homeowners policy declarations page, a contractor, or a replacement cost estimate. Not market value.
- Multiply by 0.8 — a $280,000 rebuild cost means at least $224,000 of building coverage.
- Compare it to your flood policy — or to $250,000, if 80% of your rebuild cost is higher than that.
- Recheck after a remodel or a few years of rising build costs — coverage that met the rule when you bought it may not today.
We check this on every quote.
Every flood quote we send is sized against the home's rebuild cost, so you know whether you meet the 80% rule before a claim does the math for you. Start a quote or call 1-866-990-7482.
80% rule questions, answered straight
What is the 80% rule in insurance?
It’s the requirement that your home be insured for at least 80% of what it would cost to rebuild in order to get claims paid at full replacement cost. If you insure for less, the claim is paid on a reduced basis. It’s based on rebuild cost, not market value.
Does the 80% rule apply to flood insurance?
Yes. On the NFIP, a single-family home that’s your principal residence gets building claims paid at replacement cost if the building coverage is at least 80% of the full replacement cost or the maximum available, which is $250,000 for a home. Private flood policies set their own terms, and some have their own insurance-to-value clause.
What if 80% of my home’s rebuild cost is more than $250,000?
Insuring to the $250,000 NFIP maximum counts as meeting the rule. You still won’t be paid more than $250,000, so any rebuild cost above that is uninsured unless you add excess flood insurance or choose a private policy with a higher limit.
How is a flood claim paid if I’m below 80%?
The NFIP pays the greater of the actual cash value of the damage or a proportion of the replacement cost: your building coverage divided by 80% of the rebuild cost, times the loss. The deductible is subtracted after that.
Does the NFIP pay replacement cost on a second home or rental?
No. On the NFIP, replacement cost is limited to a single-family home that’s your principal residence. Second homes and rentals are paid at actual cash value no matter how much coverage you carry. Some private flood policies offer replacement cost on those properties.
Are my belongings paid at replacement cost on flood insurance?
Not on the NFIP. Contents are always paid at actual cash value, meaning depreciated value. Some private flood policies offer replacement cost on contents, which is one reason to compare markets.
Not sure you're insured to 80%? Let's check.
Send us the address. A real Flood Nerd checks your building coverage against what the home would cost to rebuild, shops the NFIP and the private market, and sends back one clear recommendation.
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