What Is Cost Segregation and Why It Matters for Property Owners

Residential rental buildings generally use a 27.5-year depreciation period under the general depreciation system. Land is not depreciable. A $400,000 building basis would produce about $14,545 in a full year; the first year is prorated using the applicable convention. Commercial buildings generally use a different recovery period.

That is useful. But it is not the whole picture.

A property contains both building components and other assets. A cost segregation study evaluates which items qualify for shorter recovery periods based on their function, use, and construction. Classification requires more than identifying an item by name.

If shorter-life assets are included in a single building account, deductions may be spread over a longer period than required. A review can identify whether the allocations need to change.

What Cost Segregation Does

A cost segregation study is an engineering-based analysis that identifies and reclassifies those components. Every item in the property is reviewed and assigned to the correct IRS recovery period under MACRS (Modified Accelerated Cost Recovery System).

The result is a reclassified asset schedule showing which portion of your cost basis falls into 5-year, 7-year, 15-year, and 27.5-year categories. Your tax preparer uses this schedule to calculate the accelerated depreciation on Form 4562.

The amount reclassified varies by property. A residential screening estimate can help frame the opportunity, but the final allocations must come from the documented study.

What Qualifies for Shorter Schedules

The specifics depend on the property, but common 5- and 7-year personal property components include:

Carpeting and specialty flooring
Removable items where the facts support personal-property treatment; built-in cabinetry often remains a building component
Appliances (refrigerators, dishwashers, ranges)
Qualifying dedicated fixtures, subject to their function; general building lighting generally remains part of the building
Window treatments
Decorative elements in short-term rentals

Common 15-year land improvements include:

Driveways and parking surfaces
Sidewalks and walkways
Landscaping and fencing
Outdoor lighting
Swimming pools and patios

Why Timing Matters

A dollar of tax savings today is worth more than the same dollar saved in year 20. When you accelerate depreciation, you pull those deductions forward. Even if the total depreciation over the life of the property is the same, having more of it up front has real value.

For illustration, a usable $50,000 deduction at a 37% federal marginal rate has an $18,500 tax effect. This is not a promised refund or a calculation of incremental savings; timing, loss limits, and the depreciation available without a study matter.

To see what the numbers look like for your specific property, use the free savings calculator .

Does the IRS Recognize This?

The IRS publishes a Cost Segregation Audit Techniques Guide describing examination considerations. Following documented methods supports review, but the guide is not IRS approval of a provider or a particular study.

Segonomics provides documentation and methodology support under the engagement terms. This support is not a guarantee of an audit outcome.

The Decision to Make

The decision is whether earlier usable deductions justify the study fee and any additional filing work. Review the property records, expected holding period, and potential sale consequences with your tax preparer.

For short-term rentals, the ability to offset wages depends on the activity’s classification, material participation, and other loss limits. A study determines asset classifications; your tax preparer determines the treatment of the resulting deductions.

If you own a residential rental and have not ordered a study, it is worth understanding what you qualify for. Start with the savings calculator to get a rough estimate, then read about how much you can actually expect to save based on your property type and value.