Cost Segregation
Accelerate depreciation, cut your tax bill in the early years, and — if you qualify — offset W-2 income. Here's how cost segregation works, when it pays, and how to do it defensibly.
Cost segregation is how real-estate owners front-load depreciation instead of spreading it evenly over decades.
The IRS normally makes you depreciate a building over 27.5 years (residential rental) or 39 years (commercial). A cost segregation study breaks the property into its components and reclassifies the ones that qualify — carpet, cabinetry, appliances, specialty electrical, landscaping, site improvements — into 5-, 7-, and 15-year property. Those shorter-lived assets can then be depreciated far faster, and when bonus depreciation and qualified improvement property (QIP) applies, much of it can be deducted in year one.
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Open the calculator →An engineer reviews construction documents, cost records, and the property to identify and value every reclassifiable component.
Eligible components move from 27.5/39-year buckets into 5-, 7-, and 15-year property with documentation for each.
Those shorter-lived assets — plus bonus depreciation where it applies — produce a large front-loaded deduction, often in year one.
They range from rigorous engineering work to quick estimates — and the difference shows up on audit.
The gold standard. Full engineering review with line-item documentation — the most accurate and audit-defensible method, and what the IRS's Audit Techniques Guide favors.
Estimates from cost models and photos without a full site review. Cheaper and faster, but less granular and weaker if the numbers are challenged.
A broad percentage allocation with little analysis. Cheapest and quickest, but the least defensible — rarely worth it for a real deduction.
For anyone using cost segregation to offset W-2 income, audit-defensibility matters — which is why the engineering study is usually worth it. See how this fits the STR tax strategy →
A study does not create deductions. It moves them forward, and it changes the rate you pay when you sell.
Every dollar of depreciation reduces your basis, so it comes back as gain on disposition. What decides the real cost is the rate — and after a study your depreciation sits in three buckets taxed three different ways.
Carpet, cabinetry, appliances, window treatments, specialty electrical. This is §1245 property, and every dollar of depreciation comes back as ordinary income — up to 37% federal, limited only by the gain on those assets.
Paving, sidewalks, curbs, fencing, landscaping, drainage. This is §1250 property — which does not mean 25%. Under §1250(b)(1) any depreciation above straight-line is ordinary income. Take 100% bonus and nearly all of it is above straight-line: sell in year five and roughly two-thirds comes back at ordinary rates, only the straight-line third at 25%. As with the first bucket, recapture cannot exceed the gain allocated to those assets.
Structure, roof, structural HVAC, plumbing. §1250 property on straight-line, so there is no excess to recapture as ordinary income. All of it is unrecaptured §1250 gain, capped at 25% under §1(h)(1)(E).
So here is the actual trade. Without a study, essentially all of your depreciation would have sat in that third bucket at the 25% cap. A study moves the 5- and 7-year slice into the first bucket at your ordinary rate and, once bonus is claimed, pushes most of the 15-year slice there too. You are paying roughly twelve points more on the accelerated portion in exchange for taking the deduction years earlier. Over a hold of more than about three years the time value of money usually wins — but it is a trade, not free money, and it is the part most sales decks leave out.
One classification point worth knowing about. A lot of published material — including several cost-segregation firms’ own explainers — states that 15-year land improvements are §1245 property. That is wrong, and it matters, because land improvements are often the single largest accelerated bucket in a study.
§1250 is a residual definition: depreciable real property that is not §1245 property. Paving, fencing and sidewalks do not fit any category enumerated in §1245(a)(3), and Treas. Reg. §1.48-1(c) — which §1.1245-3 incorporates by reference — states that “paved parking areas … and fences are not tangible personal property.” The IRS’s own Cost Segregation Audit Techniques Guide classifies a grade-level parking lot — including its curbs, striping, landscape islands, perimeter fences and sidewalks — as §1250 property in asset class 00.3. Bonus depreciation does not change it: §168(k) is not among the provisions in §1245(a)(3)(C) that convert real property into §1245 property, though §179 is.
What that is worth is narrower than it sounds. Being §1250 does not cap the bucket at 25%. It caps only the portion equal to straight-line depreciation; the excess created by bonus still comes back as ordinary income. The real benefit is that straight-line slice at 25% rather than your ordinary rate, plus softer treatment in a §1031 exchange.
Two things this does not settle. Site lighting, poles and pylons are genuinely open — the IRS guide notes that asset class 00.3 holds both §1245 and §1250 property, so those are decided item by item. And land improvements serving manufacturing, production or utility activities can be §1245 under §1245(a)(3)(B) and may sit in a different asset class altogether (Rev. Rul. 2003-81) — an exception that does not reach residential rental or short-term-rental property. Confirm the split with whoever prepares your return before you model an exit.
Three more things decide what you actually pay:
An installment sale does not spread the ordinary part. Under §453(i), recapture taxed as ordinary income is reported in full in the year of sale, even if you received no cash that year. On a heavily accelerated property, seller financing can hand you a tax bill with nothing to pay it from.
A 1031 exchange defers it; death eliminates it. An exchange carries the recapture into the replacement property rather than erasing it, and §1245(b)(4) limits how much §1245 recapture is triggered based on what you receive. A step-up in basis at death under §1014 wipes it out entirely — so if the plan is to hold the property for life, the recapture objection largely disappears.
Declining the deduction does not help. Recapture is computed on depreciation “allowed or allowable.” Skipping it costs you the deduction and leaves the recapture in place, so always claim it.
The 3.8% net investment income tax can apply on top of all three buckets, and most states tax recapture at their ordinary rate with no equivalent of the federal 25% cap.
Accelerated depreciation is only worth something if you have income it can offset, and a hold long enough for the timing to pay for the higher exit rate.
Two questions decide it, and they are independent. First, can you use the loss this year? A passive investor’s loss is suspended under §469 and does nothing until passive income shows up. A short-term-rental operator who materially participates can usually apply it against W-2 and other active income — which is the whole reason the two strategies get discussed together. Second, how long will you hold? The deduction arrives now and the higher recapture rate arrives at sale, so a short hold that ends in a taxable sale can erase the benefit entirely.
Basis above roughly $500,000 · you have income the loss can actually offset this year · a hold of more than about three years, a 1031 exit, or a hold-to-death plan · a recent purchase or renovation · a property type with real short-life content
The loss would be suspended with no passive income in sight · you expect to sell within a couple of years · the property is land-heavy with little to reclassify · your state does not conform to bonus depreciation · the study costs a meaningful share of the benefit
One timing point that is easy to get backwards: the deduction lands in the year the property is placed in service, not the year you bought it, while the bonus rate is set by when you acquired it. Both are explained below.
Parikh Financial runs the ROI math, coordinates the engineering study, and handles the depreciation and filing.
Book a free consultationA cost segregation study is an engineering-based analysis that breaks a building into its components and reclassifies eligible parts — fixtures, flooring, appliances, land improvements — into shorter depreciation lives (5, 7, or 15 years) instead of the standard 27.5 or 39 years. That lets you front-load depreciation and cut taxable income in the early years of ownership.
A detailed engineering study typically runs a few thousand to low five figures depending on property size and complexity. Below roughly $500,000 in building basis, the fee can eat into the benefit, so the ROI math matters — which is exactly what we help you run before you commit.
Often yes. Combined with bonus depreciation and the short-term-rental material-participation rules, a study can generate a large first-year loss that offsets W-2 or other active income. The benefit depends on your holding period, tax bracket, and whether you meet the STR tests — model it first.
The accelerated depreciation is recaptured on sale. The 5- and 7-year components come back as ordinary income, and once bonus depreciation is claimed most of the 15-year land improvements do too; only the straight-line portion is capped at 25%. Cost segregation is a timing and time-value-of-money play, not free money — so the exit matters as much as year one. We model recapture before recommending a study.
General information, not tax advice. Outcomes depend on your facts and current law, which changes. Confirm with a qualified advisor before acting.
Two dates, two different jobs.
The year you claim bonus depreciation is the year the property is placed in service — ready and available for rent. That is not necessarily the year you bought it, so a property purchased one year and first listed the next takes its deduction in the second year.
The rate you get is set by when you acquired it. 100% for property acquired after January 19, 2025. Property acquired on or before that date stays on the old phase-down, which is 20% for anything placed in service in 2026.
Acquisition is measured by the written binding contract, not the closing, and there is no election to opt into 100%.