Key Takeaways
- A cost segregation study identifies parts of a building that can be depreciated over 5, 7, or 15 years instead of the standard 27.5 years for residential rental property or 39 years for nonresidential property.
- Faster depreciation increases deductions in the early years of ownership, which can lower taxes and improve cash flow.
- The One Big Beautiful Bill Act, signed July 4, 2025, restored 100% bonus depreciation for qualifying property acquired after January 19, 2025, which makes reclassified components especially valuable.
- Owners who bought property in earlier years can catch up missed depreciation with a look-back study and IRS Form 3115, without amending prior returns.
- The IRS Cost Segregation Audit Techniques Guide favors detailed, engineering-based studies.
A cost segregation study is an engineering-based analysis that breaks a building's cost into components that can be depreciated faster than the building itself. Items such as certain electrical, flooring, fixtures, and site improvements may move from a 27.5- or 39-year schedule to 5, 7, or 15 years, which increases deductions in the early years.
For business owners who own their building and for real estate investors, depreciation is one of the largest deductions available. Certified Maverick, the certification and directory network for tax strategists founded by David A. Perez, trains advisors to evaluate when a study makes financial sense. This guide explains how cost segregation works and its trade-offs.
How Does Cost Segregation Work?
Under the Modified Accelerated Cost Recovery System (MACRS), described in IRS Publication 946, buildings are depreciated slowly: 27.5 years for residential rental property and 39 years for nonresidential real property. A cost segregation study separates out components that qualify for shorter recovery periods.
| Recovery period | Typical components |
|---|---|
| 5-year property | Certain carpeting, decorative finishes, dedicated electrical for equipment, some fixtures |
| 7-year property | Certain furniture and equipment, some specialized fixtures |
| 15-year property | Land improvements such as parking lots, sidewalks, landscaping, fencing, and outdoor lighting |
| 27.5- or 39-year property | The building structure, roof, walls, and core building systems |
Reclassified components that qualify for bonus depreciation can be deducted much faster, and in some cases fully in the first year.
Who Benefits Most From a Cost Segregation Study?
A study is most often considered when these conditions apply:
- You bought, built, or substantially renovated a commercial or residential rental building
- The property's depreciable basis is large enough that faster deductions outweigh the study fee
- You expect to hold the property for several years
- You have income the extra depreciation can offset, or you qualify to use rental losses
Common examples include owner-occupied office, retail, warehouse, and medical buildings, multifamily rentals, and short-term rentals that meet the material participation rules.
How Does Bonus Depreciation Change the Value?
Bonus depreciation lets owners deduct a percentage of qualifying property's cost in the year it is placed in service. The One Big Beautiful Bill Act, signed July 4, 2025, restored 100% bonus depreciation for qualifying property acquired after January 19, 2025. Components with a recovery period of 20 years or less, which includes the 5-, 7-, and 15-year property a study identifies, can generally qualify.
Can You Do a Cost Segregation Study on a Property You Already Own?
Yes. A look-back study applies to property placed in service in earlier years. Instead of amending past returns, owners file IRS Form 3115 to change their accounting method and claim the missed depreciation as a single catch-up adjustment under IRC Section 481(a) in the current year.
What Does the Cost Segregation Process Look Like?
- Feasibility review. A specialist estimates the likely reclassification and tax benefit before you commit.
- Site visit and document review. Engineers review construction documents, invoices, and the property itself.
- Engineering analysis. Costs are assigned to components using methods the IRS Cost Segregation Audit Techniques Guide describes as most reliable.
- Report delivery. The final report supports the new depreciation schedules for your tax preparer.
- Tax filing. Your tax professional reports the new depreciation, using Form 3115 if it is a look-back study.
Is a Cost Segregation Study Worth It?
It is worth it when the present value of earlier deductions clearly exceeds the study fee and the later costs, such as recapture. A simple way to estimate cost seg ROI is to compare the tax value of the extra early deductions with the study fee. A study is less likely to pay off when the property is small, will be sold soon, or when the extra deductions cannot be used because of passive activity limits.
What Are the Risks and Limitations?
- Depreciation recapture. When you sell, accelerated depreciation may be recaptured and taxed, partly at ordinary income rates.
- Passive activity rules. Rental losses are generally passive under IRC Section 469 and may only offset passive income unless you qualify as a real estate professional or meet the short-term rental rules.
- Study quality. Estimates without engineering support are more likely to be challenged by the IRS.
- Timing of benefit. Cost segregation shifts deductions earlier; it does not increase the total depreciation over the property's life.
What's the Bottom Line?
A cost segregation study reclassifies parts of a building into 5-, 7-, and 15-year property so owners can take depreciation sooner. With 100% bonus depreciation restored for property acquired after January 19, 2025, the early-year benefit can be large. Whether it is worth it depends on the property's basis, your holding period, your ability to use the deductions, and the recapture you will face when you sell.
Frequently Asked Questions
A cost segregation study is an engineering-based analysis that divides a building's cost into components with shorter depreciation lives, such as 5-, 7-, and 15-year property. This lets owners deduct depreciation faster than the standard 27.5-year schedule for residential rentals or 39-year schedule for nonresidential buildings under MACRS.
Sometimes, but the benefit shrinks as the property's depreciable basis gets smaller, while study fees do not shrink at the same rate. A feasibility review can estimate the likely reclassification and tax savings before you commit. Holding period and your ability to use the deductions also matter.
Yes. A look-back study lets you claim depreciation you missed in prior years. You file IRS Form 3115 to change your accounting method and take the missed amount as a catch-up adjustment under IRC Section 481(a), without amending earlier returns.
It can. When you sell the property, depreciation you claimed may be recaptured and taxed, and some of it at ordinary income rates. Strategies such as a 1031 exchange may defer recapture on real property. A tax strategist should model recapture before you order a study.
Yes. The One Big Beautiful Bill Act restored 100% bonus depreciation for qualifying property acquired after January 19, 2025. Components a study identifies with recovery periods of 20 years or less, such as 5-, 7-, and 15-year property, can generally qualify.