How to Determine Your Depreciable Basis for a Cost Segregation Study

For a straightforward purchase, the following planning formula is useful.

Purchase price + capitalized acquisition costs + qualifying capital improvements - basis allocated to nondepreciable land = depreciable basis

That formula is intentionally simple. A gift, inheritance, 1031 exchange, or conversion from personal use can change the starting basis before you ever get to the land allocation.

Acquisition costs can increase basis. IRS Publication 551 includes items such as recording fees, surveys, transfer taxes, legal fees tied to the purchase, and owner's title insurance. Loan costs are handled differently. Points, loan origination fees, lender-required appraisal fees, and similar financing costs are not added to the property's tax basis in the same way.

Land itself is not depreciable. But that does not mean every dollar outside the building belongs to land. Many site improvements can be separate depreciable property. The IRS Cost Segregation Audit Technique Guide identifies items such as paving, certain fencing, sidewalks, drainage features, and some depreciable landscaping as land improvements that may fall into 15-year Asset Class 00.3. The facts matter, especially for landscaping and site utilities.

A land allocation changes the amount available for depreciation. Push too much value into land and you give up depreciable basis. Push too little into land and you create a position that may be hard to defend.

Consider an example in which land is overstated by $30,000. If 25% of that amount would otherwise have been reclassified into qualifying short-life assets, that is $7,500 of short-life basis. When those assets qualify for 100% additional first-year depreciation, a 35% marginal tax rate puts the first-year tax effect on that short-life portion at about $2,625. The rest of the $30,000 also affects depreciation over time.

The point is not to force land lower. It is to use a number you can explain and document. IRS guidance focuses on relative fair market value when a lump-sum purchase includes both depreciable and nondepreciable property.

Basis does not issue an appraisal of your land. Our job begins after the property basis and land allocation have been established. We apply engineering and tax analysis to the depreciable property, classify components, and build the schedules that support the study.

For the land split, the owner should use a supportable source and keep the documentation behind it. The IRS Cost Segregation Audit Technique Guide tells examiners to look at fair market value and appropriate appraisal practices when they review allocations between land and depreciable property.

If the property is already on a filed tax return, start there before doing any new land math.

Ask your CPA for the depreciation schedule or fixed-asset detail from the most recent return. For the building, look for the original cost or basis, placed-in-service date, recovery period, depreciation method, and accumulated depreciation. Land, if it was broken out correctly, should appear separately without depreciation.

Do not quietly replace those filed numbers with a new allocation just because a different method produces a better result. The existing schedule is part of your tax history. If it looks wrong, flag it for your CPA and decide how the correction should be handled before the cost segregation study is finalized.

One obvious red flag is a schedule that puts the entire purchase price into the building with no land allocation at all. That is not a reason to guess a replacement number. It is a reason to stop and correct the tax position deliberately.

If this is the first year of depreciation, or there is no reliable prior schedule to use, work through the land allocation in this order. Start with the cheapest source that gives a reasonable answer. Move up only when the property or the market makes the simpler method hard to defend.

For ordinary residential property, this is usually the first place to look. IRS Publications 527 and 551 both say that if you are not certain of the fair market values of the land and building, assessed values for real estate tax purposes can be used to allocate the cost between them.

Use the ratio, not the assessor's dollar amount. A county assessment may not equal what you paid. What matters for this method is the percentage of total assessed value assigned to land.

Suppose the assessor shows:

• Land of $95,000

• Improvements of $305,000

• Total assessed value of $400,000

Land is 23.75% of the assessed total. If your actual cost basis is $528,000, applying that ratio gives $125,400 to land and $402,600 to depreciable property.

Keep the source. Save a PDF or screenshot of the assessor page showing the land and improvement values. For a prior-year acquisition, use the assessment from the acquisition period when available instead of automatically using today's value.

The assessor method is not perfect. It can get weak in markets where land prices moved much faster than improvement values, on waterfront or acreage, in teardown neighborhoods, or anywhere the assessment does not resemble the economics of the property. If the ratio looks wrong before you run the study, do not force it. Move up the ladder.

A local broker can provide a market-based opinion using vacant land sales or teardown comps. This is not the same as a licensed appraisal, but it can give you a better market anchor when the assessor split looks stale or unrealistic.

If you use a broker opinion, make it useful on paper:

• Make it signed and dated on broker or agent letterhead, with license information.

• Include comparable land sales with addresses, dates, prices, and the math used to apply them to your lot.

• State clearly that the opinion is for land only and excludes depreciable site improvements.

• For a prior-year purchase, use an effective date tied to the acquisition period rather than today.

State rules on broker price opinions vary, especially when the opinion is prepared for a fee or for a tax-related purpose. Confirm that the person providing it is allowed to do so in your state.

When the land number materially changes the tax result, or the property itself is unusual, a licensed appraiser is the strongest option.

Tell the appraiser what you need. A standard lender appraisal may give you total property value without a clean land allocation. Ask for a land or site value conclusion that can support the split between nondepreciable land and the depreciable property.

For a property bought in an earlier year, the relevant value is the value at or around acquisition. A retrospective appraisal can address that historical date using market evidence from the period.

An appraisal becomes more attractive when the property is high value, land-heavy, waterfront, acreage, infill, mixed-use, or otherwise difficult to compare. If you are already ordering an appraisal for another reason, ask whether the site-value work can be added to the scope.

Before you apply a land percentage, make sure the starting basis itself is right. These situations can change it substantially.

The free Basis benefit estimate can use a temporary land assumption when you do not have the final allocation yet. That is useful for deciding whether a cost segregation study is worth exploring. It is not the number that should automatically flow into the final tax report.

When you move forward, enter the depreciable basis and land allocation supported by your records. For a prior-year property, we may also need the existing depreciation schedule so the look-back and prior depreciation calculations line up with the return history.

Keep the assessor record, broker letter, appraisal, or other support behind the land value in your own tax file. That documentation explains where the split came from if the allocation is ever questioned.