What is a cost segregation study?
A cost segregation study is an engineering-based analysis that reclassifies components of a building from the standard 27.5-year or 39-year depreciation schedule into shorter recovery periods of 5, 7, or 15 years under MACRS.
The IRS allows this because different building components have different useful lives. Carpet wears out faster than concrete. Parking lot asphalt degrades faster than structural steel. The study quantifies these differences and assigns each component to the appropriate recovery class.
For real estate investors, this means larger depreciation deductions in the early years of ownership -- translating directly into lower taxable income and improved cash flow.
How the tax savings work
Without a cost segregation study, a residential rental property is depreciated over 27.5 years using the straight-line method. That means roughly 3.6% of the depreciable basis is deducted each year.
With a study, 20-40% of the building cost is typically reclassified into shorter-lived property. Under current bonus depreciation rules, these components can be depreciated immediately in the year the property is placed in service.
Consider a $1 million property with a $800,000 depreciable basis. Without a study, annual depreciation is roughly $29,000. With a study that reclassifies 35% of the basis, you could potentially deduct $280,000 in year one.
Which properties qualify?
Almost any commercial or residential rental property can benefit. The most common property types include single-family rentals, multifamily buildings, short-term rentals, office buildings, retail spaces, warehouses, restaurants, and medical facilities.
Properties that have been recently purchased, newly constructed, renovated, or expanded are all candidates. There is no minimum property value, though the tax savings typically justify the study cost for properties valued at $300,000 or more.
- Single-family long-term rentals (27.5-year residential)
- Short-term rentals and vacation properties
- Multifamily apartment buildings
- Commercial office and retail space (39-year nonresidential)
- Industrial and warehouse properties
- Mixed-use buildings
The 5-year, 7-year, and 15-year property classes
5-year property typically includes carpeting, appliances, certain electrical systems, decorative lighting, security systems, and specialized plumbing.
7-year property includes furniture, fixtures, and certain equipment. Office furniture, restaurant equipment, and specialized storage systems often qualify.
15-year property covers land improvements such as landscaping, sidewalks, parking lots, fencing, and drainage systems.
Bonus depreciation and the OBBBA
The One Big Beautiful Bill Act restored 100% bonus depreciation permanently for qualifying assets. All 5-year, 7-year, and 15-year property identified in a cost segregation study can be fully depreciated in the year placed in service.
For investors acquiring multiple properties, the cumulative effect of cost segregation combined with bonus depreciation can generate substantial paper losses that offset other income sources.
When to commission a study
The ideal time is immediately after acquiring or completing construction on a property. However, look-back studies can be performed on properties owned for years using IRS Form 3115.
A look-back study allows you to claim cumulative depreciation adjustments from prior years in the current tax year without amending prior returns. The entire adjustment is taken in the current year.