Land Allocation in Cost Segregation: Why It Matters and How It's Determined

Every cost segregation study starts with one fundamental question: how much of the purchase price is allocable to land? Land is never depreciable under any method or law. The answer determines your entire depreciable basis — the pool from which all depreciation deductions are drawn.

Why the Land Allocation Matters So Much

Consider two $500,000 properties: one where $50,000 (10%) is allocated to land and $450,000 to improvements, and another where $150,000 (30%) is allocated to land and $350,000 to improvements. The first property has $450,000 available for depreciation; the second has only $350,000. Over 27.5 years at straight-line, the difference is $3,636/year — over $100,000 over the life of the property.

With cost segregation and bonus depreciation, the impact compounds. A larger depreciable base means more assets to reclassify into 5-year and 15-year categories, and a larger Section 481(a) adjustment for look-back studies.

How Land is Allocated

The IRS requires that land be allocated based on its fair market value at the time of purchase. Common methods:

• Property tax assessment ratio: The county assessor typically breaks assessed value into land and improvements. The ratio (land value ÷ total assessed value) applied to your purchase price gives an allocation. Most commonly used because it's readily available and defensible.
• Appraisal: A formal appraisal that separately values the land is the most authoritative method. Often used for high-value properties or when the assessed value seems anomalous.
• Comparable sales: If land in the area transacts separately (vacant lots), comparable sale prices provide market evidence.
• Cost approach: Subtracting the cost to reproduce the improvements from the total purchase price yields an implied land value.

Common Mistakes in Land Allocation

• Using the seller's original allocation: What the prior owner paid and how they allocated it is not relevant to your purchase price allocation. You allocate based on value at your acquisition date.
• Ignoring high land value markets: In urban areas, coastal markets, or desirable locations, land can represent 40–60% of value. Failing to reflect this in the allocation results in overstated depreciable basis — which can be challenged by the IRS and creates risk at audit.
• Depreciating land improvements as the building: Land improvements (driveways, landscaping) should be separated from both land and building structure. They have a 15-year depreciable life — they're improvements to land, not land itself.

Land Allocation in a Cost Segregation Study

A professional cost segregation study includes a land allocation analysis. The engineer uses the property tax assessment ratio as a starting point and adjusts based on comparable land sales or appraisal data if there's reason to believe the assessment ratio is inaccurate.

The allocation is documented in the study report and should be consistent with the allocation used on your tax return. An aggressive under-allocation to land (overstating the depreciable basis) is a red flag in an IRS examination.