Cost Segregation Studies for Small Business Commercial Property

By Yarik Yarosh, CPA ·September 5, 2026 ·Updated September 23, 2026 ·6 min read

Written by Yarik Yarosh, CPA (US & Canada) September 5, 2026 · FL CPA license AC61704 · CPA Ontario

Commercial buildings are depreciated over 39 years under MACRS (27.5 years for residential rental). That means a $500,000 building generates only $12,821/year in depreciation ($500,000 / 39). A cost segregation study reclassifies certain building components into shorter depreciation categories: 5-year property (carpeting, decorative fixtures, special electrical), 7-year property (furniture, office equipment built into the building), and 15-year property (land improvements like parking lots, landscaping, sidewalks). The reclassified components can then be deducted using bonus depreciation (100% under OBBBA for property acquired after January 19, 2025, restored from the phase-down), generating a massive first-year deduction.

✓Key takeaway

How cost segregation works:

Without a cost segregation study:

$500,000 building (excluding land)
39-year straight-line depreciation
Annual deduction: $12,821
After 5 years: $64,103 in total depreciation

With a cost segregation study: The study identifies and reclassifies:

5-year property: 15-25% of building cost ($75,000-$125,000)
- Carpet and vinyl flooring
- Decorative lighting
- Specialized electrical (dedicated circuits for equipment)
- Signage
- Window treatments
- Accent walls and decorative finishes
7-year property: 5-10% of building cost ($25,000-$50,000)
- Built-in cabinetry
- Specialized plumbing (for specific equipment)
15-year property: 10-20% of building cost ($50,000-$100,000)
- Parking lot and paving
- Landscaping
- Sidewalks and curbing
- Exterior lighting
- Fencing
- Site drainage
Remaining 39-year property: 50-70% of building cost ($250,000-$350,000)
- Structural walls, roof, foundation, HVAC (central), basic electrical, basic plumbing

Year 1 deduction with bonus depreciation:

5-year property ($100,000): 100% bonus depreciation = $100,000 deduction
7-year property ($30,000): 100% bonus depreciation = $30,000 deduction
15-year property ($70,000): 100% bonus depreciation = $70,000 deduction
39-year property ($300,000): straight-line = $7,692 deduction (a full-year figure; the mid-month convention makes Year 1 smaller)
Total Year 1: $207,692 (vs. $12,821 without cost segregation)
Additional first-year deduction: $194,871

Tax savings at 32% marginal rate: $194,871 x 32% = $62,359

Cost of a study: $5,000-$15,000 for a typical small commercial property. The ROI is dramatic: spend $10,000 to save $62,000+ in federal tax.

Who should get a cost segregation study:

Owners of commercial property purchased or built for $300,000+
The study is most valuable in the purchase/construction year (bonus depreciation on the full reclassified amount)
Can be done retroactively on property already in service (IRS allows a “look-back” study with a Section 481(a) catch-up adjustment, no need to amend prior returns)
NOT worthwhile for very small properties (under $200,000 building value) because the study cost exceeds the marginal tax savings

Depreciation recapture warning: When the property is sold, the accelerated depreciation is recaptured:

Personal property (5, 7-year) recapture under IRC 1245: ordinary income rate (up to 37%)
Real property (15, 39-year) recapture under IRC 1250: 25% rate on unrecaptured Section 1250 gain
The cost segregation study defers tax, it does not eliminate it
If the owner plans to hold the property long-term (10+ years) or use a like-kind exchange: the deferral is very valuable (time value of money)

When does cost segregation make sense for small business?

Hypothetical example

Round numbers. A dentist buys a standalone commercial building for their practice. Purchase price: $600,000. Land value: $100,000. Building value: $500,000. The dentist plans to hold the property for 15+ years.

Without cost segregation:

Annual depreciation: $500,000 / 39 = $12,821
Year 1 tax savings (35% bracket): $4,487
10-year total depreciation: $128,210

With cost segregation (study cost: $8,000): Reclassified property:

5-year: $100,000 (dental-specific electrical, plumbing for treatment rooms, decorative finishes, flooring)
7-year: $25,000 (cabinetry, built-in storage)
15-year: $75,000 (parking lot, landscaping, signage, exterior lighting)
39-year: $300,000 (remaining structure)

Year 1 deductions:

5-year (bonus): $100,000
7-year (bonus): $25,000
15-year (bonus): $75,000
39-year (straight-line): $7,692 (full-year figure; mid-month convention trims Year 1)
Total: $207,692

Year 1 tax savings: $207,692 x 35% = $72,692 Minus study cost: $8,000 Net Year 1 benefit: $64,692

Without the study, the dentist would have claimed $12,821 and saved $4,487. The cost segregation study generated an additional $60,205 in net tax savings in Year 1.

Present value comparison (10 years, 5% discount rate): Over 10 years, both approaches deduct the same total amount of depreciation. But the cost segregation study front-loads the deduction. The present value of the tax savings is approximately $20,000-$30,000 higher with cost segregation because the money saved in Year 1 can be invested or used for 10+ years before the “catch-up” happens (lower depreciation in later years).

If the dentist sells in Year 10 via 1031 exchange: The accelerated depreciation rolls into the replacement property. The recapture is deferred until the dentist exits real estate entirely (or passes the property to heirs, who receive a stepped-up basis at death under IRC 1014, eliminating the recapture entirely).

Illustrative numbers only, not a real client and not advice for your facts.

Does bonus on a cost seg study depend on the purchase date?

Yes. The 100% rate applies to property acquired after January 19, 2025, and property isn’t treated as acquired after the date a written binding contract was signed. So the test is when you contracted to buy the building. The year you place it in service only sets the rate for property acquired earlier.

If a dentist signed the purchase contract before January 20, 2025, the reclassified components get 40% bonus if placed in service in 2025 and 20% if placed in service in 2026, with regular MACRS on the rest. Section 179 runs on the tax year instead. The limit is $2,500,000 for tax years beginning in 2025 and $2,560,000 for 2026, but it only covers section 1245 property and a short list of elected building improvements, and it can’t exceed your business income.

Does California follow bonus on a cost segregation study?

Not for personal income tax filers. California doesn’t conform to federal bonus depreciation, so on a California personal return the reclassified components don’t get bonus even when you took 100% federally. California’s Section 179 limit is $25,000, with a $200,000 threshold (2025 FTB 3885A instructions), which covers very little of a typical study.

That leaves a federal and state difference to track. On the federal return, regular MACRS on the components only happens if you elect out of bonus for that class of property, and the 39-year structure stays on straight line either way. Other states set their own rules, so check yours before assuming a study pays off the same way on the state return. The real estate investor guide and Cost Segregation Studies: Accelerating Depreciation on Commercial Property cover the federal side in more depth.

When does a cost segregation study pay for itself?

A cost segregation study typically pays for itself when the building’s purchase price or construction cost exceeds $1 million, though properties with heavy tenant improvements or specialized systems can benefit at lower values. The study reclassifies building components from 39-year (commercial) or 27.5-year (residential) property into 5, 7, or 15-year categories, accelerating depreciation deductions. Common reclassified items include carpeting and floor coverings (5-year), decorative lighting and millwork (7-year), site improvements like parking lots and landscaping (15-year), and specialized electrical and plumbing serving specific equipment. The tax savings from a cost segregation study depend on the bonus depreciation percentage in effect, your marginal tax rate, and the percentage of building costs that can be reclassified, which typically ranges from 15% to 40% of total building cost.

Want this checked against your own situation?

Start with a Diagnostic: a CPA licensed in the US and Canada reads your file and tells you in writing what's wrong and how to fix it, three to four business days after you finish the questions. The report is $250. If you hire us for any work after that, you get the $250 back as a discount on that work. Or send us your return or your letter and get a fixed price, free.

Start a Diagnostic →See prices

Get a fixed price, free

Get the next cross-border guide by email

One or two plain-English guides a week on US-Canada tax. No spam, unsubscribe anytime.

Cite this page

Yarik Yarosh, CPA. "Cost Segregation Studies for Small Business Commercial Property." Blue Cloud CPA, September 5, 2026, updated September 23, 2026. https://bluecloudcpa.com/guides/small-business-cost-segregation-study-guide

This guide is general information, not tax advice for your specific situation. Which points apply, and how, depends on your facts.