Short answer
Cost segregation applies to residential rental property in the same way it applies to any depreciable building. The house, duplex or apartment building itself is residential rental property depreciated over 27.5 years. A study identifies the parts of the purchase that are not the building: land, which is never depreciated; land improvements such as paving, fencing and site drainage, which are 15-year property; and tangible personal property such as appliances, carpeting and furniture, which is 5-year property. Those shorter-lived parts can be depreciated faster and, when they qualify, expensed in the first year under bonus depreciation. Whether that helps a particular owner depends on the size of the basis, the property's makeup, the passive activity rules, the holding period and the recapture on sale. This article explains the residential rules, what a study typically finds, and the limits. It is general education, not tax advice.
What "residential rental property" means
The Internal Revenue Code defines residential rental property as a building or structure from which 80 percent or more of the gross rental income for the year comes from dwelling units. A dwelling unit is a house or apartment used to provide living accommodations. Units in a hotel, motel or similar establishment where more than half the units are used on a transient basis are not dwelling units, which is why short-term rentals are treated in a separate article.
Publication 527 adds two practical points. Residential rental property is depreciated over 27.5 years using the straight line method and a mid-month convention. And if you live in part of the building, the fair rental value of your part counts in gross rental income for the 80 percent test.
By contrast, nonresidential real property is recovered over 39 years. The 27.5-year period is already the shorter of the two, which is one reason a study on a residential building changes less than a study on a commercial one of the same cost. The personal property and land improvements are where the difference is made.
What a study separates in a residential building
| Component | Class | Why it is separate |
|---|---|---|
| Land | Not depreciable | Land does not wear out, become obsolete or get used up |
| The building: structure, roof, exterior, general electrical, plumbing and HVAC serving the building | 27.5-year residential rental property | The building and its structural components |
| Paving, driveways, curbs, fencing, retaining walls, site drainage, depreciable landscaping | 15-year land improvements | Improvements to the land that are not the building |
| Appliances, carpeting, furniture, window treatments, certain equipment serving a business function rather than the building | 5-year property | Tangible personal property used in the rental activity |
The rows are illustrative. The classification of any particular item rests on its function and the law, and a study documents that reasoning item by item.
A single-family house on a small lot usually has less land improvement and personal property than an apartment building with parking, site lighting, laundry equipment and furnished units. That is why "how much will a study find" cannot be answered by a percentage; the answer is in the property and its records.
What changes on the return
Two things change when a study is applied.
Timing. The 5-year and 15-year property is depreciated far faster than 27.5-year property. Total depreciation over the life of the property does not increase; it arrives earlier.
Bonus depreciation. Bonus depreciation applies to qualified property, generally property with a recovery period of 20 years or less, which includes the 5- and 15-year property a study identifies but not the 27.5-year building. For qualified property acquired after January 19, 2025, the 2025 law made a permanent 100 percent first-year deduction available, and the IRS issued interim guidance in January 2026. For a building acquired in 2025 or later, the personal property and land improvements a study identifies may be deducted largely in the first year.
For a building placed in service in an earlier year, the study is generally applied through a change in accounting method on Form 3115 under the automatic consent procedures, with a catch-up adjustment, rather than by amending prior returns. That is a matter for your tax adviser and a separate article.
What limits the benefit
A larger first-year deduction is only useful if it reduces tax you would otherwise pay. Several rules decide that.
- Passive activity limits. Rental real estate losses are generally passive. For many owners, a loss created by accelerated depreciation cannot offset wages or business income in the same year; it is suspended and carried forward. A special allowance of up to $25,000 may be available to owners who actively participate, phased out at higher modified adjusted gross income, and taxpayers who qualify as real estate professionals are treated differently. Which of these applies to you is the first question for your adviser.
- Recapture on sale. Depreciation claimed on 5-year property is recaptured as ordinary income when the property is sold. Unrecaptured gain on the building is taxed at a maximum rate of 25 percent. Accelerating depreciation moves tax between years and moves some of it into a higher-rate bucket at sale. The longer you hold, and the more you do with the deferred tax in the meantime, the more the trade favors the study; a sale two years later can undo it.
- The size of the basis. A study costs money. On a small basis, the timing difference after the fee may be modest. Your adviser can estimate the effect before you commit.
- Your other elections. The tangible property regulations allow a de minimis safe harbor election for low-cost items and set separate rules for improvements. Repairs, improvements and personal property bought after acquisition interact with the study; keep your adviser informed of what you are buying and doing to the building.
Common situations
A single-family rental bought this year
The building is 27.5-year property. Land is separated first. A study looks for depreciable land improvements and personal property; with modest amounts of both, the question is whether the timing benefit exceeds the cost of the study once the passive activity rules are considered. Ask your adviser before engaging a practitioner.
A furnished multi-unit building
Furniture, appliances, carpeting and equipment can be a meaningful share of the basis, and site work adds 15-year property. A study is more likely to be worth discussing. The same limits apply.
A building you have owned for years
A study can still be applied through a change in accounting method, generally without amending prior returns. The prior depreciation schedule, the original closing statement and any renovation records are the starting evidence.
A building you live in and rent
The 80 percent test includes the fair rental value of your own unit. Personal use also affects what you may deduct. Get advice before assuming the rental rules apply to the whole building.
Evidence a residential study needs
- The closing statement or construction cost records.
- An appraisal or other evidence for separating land.
- Drawings, specifications and contracts where they exist; for older houses, a site visit and photographs do more of the work.
- Invoices for appliances, flooring, fixtures and site work bought separately.
- The existing depreciation schedule if the property was placed in service in an earlier year.
A practitioner who asks only for the purchase price and the address is not preparing the kind of study the IRS describes.
What people ask on Reddit and other forums
The searches that lead people to these threads are usually phrased "cost segregation residential rental property", "cost segregation single family rental", "27.5 year depreciation".
The "cost segregation reddit" threads on r/realestateinvesting and r/landlord are mostly small-property owners asking whether the rules apply to them. Answered from the sources below:
"Does cost seg work on a single-family house?" The rules apply to any depreciable rental building. Whether a study is worth its fee on a small house depends on the basis, the personal property and land improvements, your other income and the passive activity rules.
"My W-2 is high. Can I use the loss?" Rental losses are generally passive. Unless you qualify for the special allowance, are a real estate professional, or have passive income to offset, the loss is suspended and carried forward. A study can be accurate and still not help this year.
"Is an Airbnb residential?" Not necessarily. Units used on a transient basis are not dwelling units for the 80 percent test, so a short-term rental may be 39-year nonresidential property. See the separate article.
"I bought years ago. Too late?" Generally no. A study can be applied through a change in accounting method rather than amended returns.
Questions people also ask
Can I do cost segregation on a single-family house?
Yes. The rules apply to any depreciable rental building. Whether the study is worth its cost for a small house is a separate question your adviser can answer.
Is an Airbnb residential rental property?
Not necessarily. Units used on a transient basis are not dwelling units for the 80 percent test, so a short-term rental may be nonresidential real property with a 39-year recovery period. That and the material participation rules are covered in a separate article.
Does bonus depreciation apply to the house itself?
No. Bonus depreciation applies to qualified property with a recovery period of 20 years or less. The 27.5-year building is not qualified property; the 5- and 15-year property a study identifies can be.
Will a study lower my taxes this year?
Only if the accelerated deductions can be used this year, which the passive activity rules decide for most owners. A study can produce a suspended loss rather than a current saving. Ask your adviser.
What happens when I sell?
Depreciation on the personal property is recaptured as ordinary income; unrecaptured gain on the building is taxed at up to 25 percent. Plan the study with the sale in mind.
Sources
- https://www.law.cornell.edu/uscode/text/26/168 — 26 U.S.C. §168(e)(2)(A) (residential rental property; dwelling unit) and §168(k)(2)(A) (qualified property).
- https://www.irs.gov/publications/p527 — IRS Publication 527 (2025), Residential Rental Property: Chapter 2 (depreciation, property classes) and Chapter 3 (passive activity limits).
- https://www.irs.gov/publications/p946 — IRS Publication 946 (2025), How To Depreciate Property: Chapter 4, Table 4-1.
- https://www.irs.gov/newsroom/treasury-irs-issue-guidance-on-the-additional-first-year-depreciation-deduction-amended-as-part-of-the-one-big-beautiful-bill — IR-2026-06 (January 14, 2026), guidance on the permanent 100 percent additional first-year depreciation deduction (Notice 2026-11).
- https://www.law.cornell.edu/cfr/text/26/1.263%28a%29-1 — 26 C.F.R. §1.263(a)-1(f), de minimis safe harbor election.
- https://www.irs.gov/publications/p544 — IRS Publication 544 (2025), Sales and Other Dispositions of Assets: Chapters 3 and 4.
- https://www.irs.gov/instructions/i3115 — Instructions for Form 3115, Application for Change in Accounting Method.