How to Split Land vs Building for Rental Depreciation

TL;DR: Land never wears out, so the IRS forbids depreciating it. When you buy rental property, you must split the purchase price into a land component and a building component — only the building depreciates. Use the property tax assessor's land-to-building ratio as your starting point unless you have an independent appraisal that supports a different split. Document the allocation method in writing at purchase and use the same method at sale to avoid audit risk.

_Last reviewed: July 2026 · 6 min read_

You paid one price for the property — but the tax code treats land and building as two separate assets. Land doesn't depreciate. The building does. Getting that split wrong costs you depreciation deductions every year for decades, and changing it later raises red flags.

Okoniq Property Hub logs the original allocation and tracks basis adjustments — so when you sell years later, the same split method is sitting in the file.

Why does the IRS care how you split land from building?

The tax code lets you recover the cost of a rental building through depreciation. Land is considered permanent — it doesn't wear out — so it's excluded. If you paid $500,000 and allocate $100,000 to land, you depreciate $400,000. If you allocate $200,000 to land, you depreciate $300,000. The difference is thousands of dollars in annual deductions over the recovery period.

The IRS knows this creates an incentive to call everything "building" and nothing "land". So you're required to make a reasonable allocation at purchase and document the method. "Reasonable" means a method grounded in an independent source — not one you picked to maximize depreciation. If your split is challenged in an audit and you have no written support, the IRS can impose its own allocation, and you lose the dispute by default.

Internal link: depreciation-recapture-at-sale explains why you'll see this allocation again when you sell — the building portion you depreciated is taxed at recapture rates.

What's the default method — property tax assessor values?

Most landlords start with the local assessor's separate land and building values. Every taxing jurisdiction publishes them — they're public record. If the assessor says the land is 20% of the total assessed value and the building is 80%, apply that same 20/80 ratio to your purchase price.

Example: You paid $500,000. The county assessor shows the property assessed at $400,000 total — $80,000 land, $320,000 building. That's 20% land, 80% building. Apply the ratio to your $500,000 purchase price: $100,000 land, $400,000 building.

The assessor method is defensible because it's an independent third-party valuation. The IRS generally accepts it unless the numbers are obviously stale or the assessor lumps land and building together without a split. In states where assessors do publish separate values, this is the path of least resistance — and it satisfies the "reasonable allocation" standard in most cases.

Internal link: appeal-property-tax-assessment covers when and how to challenge the assessor's total valuation — but for depreciation purposes, you're usually borrowing their ratio, not their absolute dollar amount.

When does an appraisal override the assessor split?

An independent appraisal ordered at purchase can support a different allocation — and the IRS gives appraisals more weight than assessor values if there's a conflict. An appraiser walks the property, reviews comparable sales, and estimates land value separately from improvement value. That makes it stronger evidence than a county database that might be years out of date.

You'd order an appraisal when:

• The assessor's split looks wrong — e.g. you're in a high-land-value market but the assessor shows 90% building
• You bought a fixer and the assessor's building value includes improvements you haven't made yet
• You suspect the assessor lumped site work (grading, retaining walls, driveways) into "land" when IRS rules let you depreciate those as land improvements

Land improvements — anything permanently attached to the land that isn't the building itself — depreciate on a 15-year recovery period. An appraisal that breaks out paving, fencing, or landscaping separately gives you more to depreciate than a simple land-vs-building split. That extra detail is why cost segregation studies exist — but even a standard appraisal that separates site work is a step up from raw assessor data.

Internal link: cost-segregation-basics explains the next level — hiring an engineer to reclassify building components into shorter recovery periods.

Why does consistency at sale matter?

You'll use the same land allocation twice: once at purchase to set up depreciation, and again at sale to calculate gain. If you allocated 20% to land at purchase, you should allocate 20% to land when computing basis at sale. Switching methods — say, using assessor values at purchase and an appraisal at sale — invites scrutiny. The IRS sees it as cherry-picking to minimize tax at both ends.

Example: You allocated $100,000 to land and $400,000 to building at purchase. Over 20 years you depreciated $150,000 of the building. At sale, your adjusted basis in the building is $250,000. If you suddenly claim the land was worth $200,000 at purchase (cutting the depreciable building to $300,000), you've created a $100,000 phantom gain or loss depending on which way you're trying to optimize. The IRS flags the inconsistency and you're in an audit explaining why the land value doubled in your records but not in reality.

The fix: write down the allocation method at purchase and attach it to the property's basis file. "Land value allocated using county assessor's 2026 ratio of 22% land, 78% building." When you sell in 2045, use the same 22/78 ratio applied to your original purchase price — adjusted for any capital improvements you added to building basis in the meantime.

Internal link: stepped-up-basis-real-example covers a related consistency rule — heirs who inherit property get a new basis, so the old allocation resets.

What documentation should you keep?

Write a one-page allocation memo at closing and file it with the settlement statement. Include:

• Purchase price and closing date
• The land and building dollar amounts
• The source — "allocated using County X assessor's 2026 assessed values of $Y land, $Z building" or "allocated per appraisal dated [date] by [appraiser name]"
• If you used an appraisal, attach a copy

Keep the memo and any supporting documents (assessor printout, appraisal) for as long as you own the property plus the statute of limitations after you sell. This is your proof if the IRS questions the split. Without it, you're arguing from memory against an examiner with your return in front of them — and you lose.

If you make a capital improvement — add a garage, replace the roof — document whether it's a building improvement or a land improvement. A new roof goes to building basis and extends the recovery period. A new driveway is a land improvement and goes on the 15-year schedule. Both increase your basis, but the depreciation treatment differs. Keep the contractor invoice and note the classification in the same file.

Internal link: schedule-e-deductions-2026 lists what counts as a deductible repair vs a capitalized improvement — once you capitalize it, the land-vs-building question comes back.

FAQ

Can I allocate zero dollars to land if the lot is tiny?

No. Even a small urban lot has value — someone would pay something for the land even if the building burned down. The IRS expects a reasonable allocation, not a creative one. Use the assessor's ratio or get an appraisal. An allocation of zero to land is per se unreasonable unless you're depreciating a mobile home on leased land, and even then the lease itself might have basis.

What if the county assessor doesn't publish separate land and building values?

Order an appraisal. A licensed appraiser can estimate the land value by looking at comparable vacant-lot sales in the area and subtracting that from your purchase price. Document that you used the appraisal because the assessor didn't provide a split. This happens in some rural counties where the assessor uses a one-line total value — you're not stuck, you just need to create the record another way.

Do I redo the allocation every year as market values change?

No. The allocation is fixed at purchase. Market appreciation or decline doesn't change the original split — you're recovering the historical cost, not current market value. If you make a major capital improvement, you allocate the cost of that improvement between land and building using the same method, but the base allocation from the purchase date stays put. At sale, gain or loss is measured against your adjusted basis, not a re-allocated basis.

Can I use one method at purchase and a different method at sale if I get an appraisal later?

You can, but you're adding audit risk. The safer path: if you realize after purchase that the assessor split was wrong, get an appraisal within the first year and file an amended return with a corrected allocation. Explain the change in writing. Switching methods 10 years later at sale without a contemporaneous appraisal looks like retroactive tax planning, and the IRS can disallow it.

Does the allocation affect property tax I owe the county?

No. Your depreciation allocation is for federal tax purposes. The county assesses the property for property tax using its own methods — usually comparable sales or a formula in state statute. You can't lower your property tax by claiming a different land-to-building split on your tax return. The two numbers exist in parallel, and the only place they touch is that you borrow the county's ratio as evidence for your federal allocation.

<div class="glass rounded-2xl p-5 mt-7 max-w-4xl border border-red-400/30 bg-red-500/5"> <div class="flex items-start gap-3"> <span class="text-2xl flex-shrink-0">⚠️</span> <div class="flex-1 min-w-0"> <p class="text-red-200 text-sm font-bold">Not tax advice</p> <p class="text-slate-300 text-xs mt-1 leading-relaxed"> This post assumes you own U.S. rental property and depreciate it on Schedule E. It does not account for your bracket, your state's rules, partnership or S-corp allocations, or legislation enacted after July 2026. Tax rules change and depend on your specific situation. Talk to a licensed CPA before acting on anything here, and confirm current figures on IRS.gov. </p> </div> </div> </div>