Allocating Tax Basis Between Land and Building

When you buy a rental property or investment real estate, the purchase price must be split between land and building. Only the building fraction is depreciable—land is never depreciated. Allocating this basis correctly determines your annual deduction amount and can be audited if the IRS suspects you’ve inflated the building share to boost write-offs.

Why Land and Building Must Be Separated

Under generally accepted accounting principles and IRS Section 168, land is a non-wasting asset. It doesn’t deteriorate, doesn’t have an economic life, and therefore cannot be depreciated. A building, by contrast, deteriorates from use, weather, and age—it has a finite economic life and is depreciable.

When you purchase a property, the entire purchase price (excluding closing costs) must be allocated between these two components. Get this wrong, and you either:

• Overstate depreciation (claiming a deduction on land), which invites IRS scrutiny; or
• Understate depreciation (allocating too much to land), which leaves money on the table in annual deductions.

The allocation also affects your cost basis, which determines future capital gains tax when you sell. Land basis typically rises over time as property values appreciate; building basis declines as you claim depreciation deductions.

The Three Common Allocation Methods

Assessed Value Ratio (Most Common, Least Rigorous)

Most property owners use the assessed value ratio method: look up the assessor’s land and building values from your county tax records and apply that ratio to the purchase price.

Example:

• Purchase price: $400,000
• County assessor values: Land $100,000, Building $150,000
• Total assessed: $250,000
• Land ratio: 100/250 = 40%; Building ratio: 150/250 = 60%
• Your allocation: Land basis $160,000, Building basis $240,000

Strength: Easy, fast, publicly documented.
Weakness: Assessed values lag market values and vary widely by jurisdiction. The IRS views this method with skepticism if the property is in a high-appreciation area.

Independent Appraisal (More Defensible)

An independent appraisal by a licensed appraiser separately values the land and building at the time of purchase.

• Cost: $500–$2,000+ depending on property complexity.
• Process: The appraiser uses comparable land sales, cost-to-build estimates, and market data to split the purchase price.
• IRS view: More defensible than assessed value, but still subject to challenge if the allocation is unusually aggressive.

Example:

• Purchase price: $400,000
• Appraiser allocates: Land $140,000, Building $260,000
• You use the appraisal allocation for your cost basis.

If the IRS challenges the appraisal, you can cite the appraiser’s methodology and qualifications. However, the IRS may still argue the appraisal is biased or inflated.

Cost Segregation Study (Most Rigorous, Expensive)

A cost segregation study is a detailed engineering and financial analysis that breaks down the building into components with different depreciable lives. Instead of depreciating the entire building over 27.5 or 39 years, it identifies:

• Land improvements (parking, landscaping, sidewalks): 15 years
• Building systems (HVAC, plumbing, electrical): 5–15 years
• Furniture and fixtures: 5–7 years
• Land: non-depreciable

Cost: $5,000–$15,000+ for a commercial property; $2,000–$5,000 for residential.

Benefit: Allows accelerated depreciation on shorter-lived assets, generating larger early-year deductions (and larger recapture when you sell). Highly defensible if performed by a licensed engineer.

Drawback: The recapture tax when you sell is often 25%, so you recoup some of the tax savings. Cost segregation is most valuable if you hold the property long-term or plan a 1031 exchange.

IRS Scrutiny and Red Flags

The IRS heavily scrutinizes land-versus-building allocations because overstatement of building value directly inflates annual depreciation deductions. Watch for these audit triggers:

Allocation Adjustments and Amendments

If the IRS disallows your allocation and proposes a different split, you have options:

1. Agree and file Form 3115 (Application for Change in Accounting Method) to amend prior returns and recalculate depreciation.
2. Challenge the IRS valuation in the audit process, presenting your appraisal or cost segregation study.
3. Settle on a compromise allocation if neither side has bulletproof evidence.

Disputes over allocation can be costly and time-consuming. The cost of an independent appraisal or cost segregation study upfront is far cheaper than defending a challenged allocation in audit.

Practical Checklist for Purchase

When you buy a rental or investment property:

• Gather assessor data immediately; many records are publicly available online.
• Request an independent appraisal if the purchase price exceeds $300,000 or the property has unusual features.
• Consider a cost segregation study if the property is commercial, multi-unit, or you expect significant bonus depreciation.
• Retain all supporting documents—appraisal reports, assessor statements, purchase contracts—for at least six years.
• Disclose your allocation method in your tax return or Schedule E commentary.
• Review the allocation with a CPA before filing; don’t guess.

See also