Residential rental property depreciates over 27.5 years. That is the starting point our tax deductions guide covers, and for most owners it is the whole of the story.
Cost segregation is the technique that sits on top of it — and it is worth understanding properly, because it is marketed aggressively and described inaccurately more often than most tax strategies.
What a study actually does
A cost segregation study is an engineering-based analysis that looks at a building and reclassifies its components.
Rather than depreciating everything over 27.5 years, the study identifies items that properly belong in shorter recovery periods — categories of personal property and land improvements that carry much shorter schedules than the structure itself.
The effect is to move deductions forward, into the early years of ownership.
It is timing, not magic
This is the sentence the marketing tends to skip.
Cost segregation accelerates deductions you were largely going to take anyway. The benefit is the time value of money — a deduction now is worth more than the same deduction spread across three decades — not a larger total deduction.
That is a real benefit. It is not free money, and an owner evaluating it should be modeling a cash-flow timing advantage rather than a windfall.
Where bonus depreciation stands
Bonus depreciation allows an immediate deduction of a large share of qualifying assets' cost, and it is what makes cost segregation powerful when it applies.
It had been phasing down and was on a path to zero. That changed: the One Big Beautiful Bill Act, enacted 4 July 2025, permanently restored 100% bonus depreciation under §168(k) for qualifying assets acquired and placed in service after 19 January 2025.
Qualifying property is tangible depreciable business property with a recovery period of 20 years or less — which is precisely the category a cost segregation study identifies.
The retroactivity limit, which is where this gets oversold
Here is the point most likely to be glossed over in a sales conversation.
A study performed today on a property acquired in an earlier year does not automatically make those shorter-life assets qualify for the current 100% bonus depreciation rules. The acquisition and placed-in-service timing governs.
There may still be value in a study on an older property through other mechanisms. But an owner who bought a Brooklyn building in 2019 and is being told they can run a study now and take 100% bonus is being told something that needs checking very carefully with a tax advisor before any money changes hands.
Confirm the current rules and how they apply to your specific acquisition with a qualified tax professional. This area changed materially in 2025 and the details matter.
Recapture is the part that comes back
When you sell, depreciation you took is recaptured — and the rate depends on what was depreciated.
Section 1250 real property — the building itself — carries a maximum federal recapture rate of 25% on the depreciation portion.
Section 1245 personal property — the components a cost segregation study reclassifies — is recaptured as ordinary income, up to your top marginal rate.
Read those two together, because it is the real trade-off. Accelerating depreciation through reclassification can convert what would have been 25%-rate recapture into ordinary-rate recapture. Whether that is a good exchange depends on your rate now versus your expected rate later, and on how long you hold.
Holding until death can change it more sharply still — a step-up in basis can eliminate the deferred gain and recapture altogether, which is worth understanding before accelerating anything. A 1031 exchange can change the picture by deferring the gain and recapture — but the interaction is technical and depends on the specifics of both properties. That is a question for a qualified intermediary and your tax advisor together, not one to reason out from general principles.
The variables that actually decide it
A tax advisor will model these. An owner should know what they are:
- Cost basis of the property, which sets the size of the opportunity.
- Your marginal rate now versus expected later — the whole recapture calculation turns on this.
- Intended holding period. A long hold changes the value of acceleration considerably.
- Whether you can use the deductions. Passive activity loss rules limit what many owners can actually apply against other income, and a large accelerated deduction that gets suspended is worth much less than it appears.
- The cost of the study, which sets a floor on the property value where it makes sense at all.
That fourth point is the one that most often makes the strategy less useful than expected for a smaller owner, and it is worth establishing early rather than after commissioning a study.
Where this leaves a Brooklyn owner
Cost segregation is a genuine tool and it is not a universal one. It tends to make most sense on a higher-basis property, held by an owner who can actually use the deductions, with a holding period and rate profile that make the recapture trade favorable.
For a great many owners of small Brooklyn buildings, the honest answer is that the basics matter more: taking every deduction you are entitled to, tracking repairs versus improvements correctly, and keeping records good enough that your accountant is not reconstructing the year from receipts.
We are property managers, not tax advisers. We do not prepare returns, commission studies, or advise on tax strategy. What we do is keep the records that make any of this possible — which is a large part of what financial reporting and investment property management are for.
If your books are not in a state where your accountant could evaluate this, schedule a consultation or call 718-568-9278.
This article is general information, not tax or legal advice. Depreciation, bonus depreciation, recapture and passive activity rules are technical and changed materially in 2025. Consult a qualified tax professional about your own position before acting on any of it.