Short-Term Rental Cost Segregation: Complete Guide (2026)

Key numbers to anchor the rest of this guide:

• 22–30% of purchase price is the typical bonus-eligible share on a well-furnished short-term rental, per the DepreciMax 2026 study of 197 short-term rental markets.
• $3,000–$8,000 is the current fee range for a formal engineer-prepared cost segregation study on a single-family short-term rental (as of October 2026).
• 100% bonus depreciation was permanently restored by the One Big Beautiful Bill Act (OBBBA) for property acquired and placed in service after January 19, 2025.
• ~$222,000 is the Year-1 bonus write-off on a $1,000,000 purchase at the Gold medal threshold (22.2% bonus-eligible) — ~$82,140 of federal tax savings in the 37% bracket.
• Form 3115 enables a lookback cost segregation study on a property placed in service in a prior year, with a §481(a) catch-up adjustment that avoids amended returns.

This guide walks through what gets reclassified, where the economics tip for a single-family STR, how the lookback election works on a property you already own, and how to pre-screen a specific address before paying $3,000–$8,000 for a formal study. We also work a real property in detail: 1724 Mohican Dr in South Lake Tahoe, California — a Gold-tier mountain-town STR — showing the full before-and-after bonus depreciation math.

What is cost segregation for a short-term rental?

Cost segregation is an engineering-based tax study that splits the purchase price of a rental property into its MACRS depreciation classes. Without a study, the depreciable basis of a short-term rental defaults to 39-year nonresidential real property (if the average guest stay is 7 days or less) or 27.5-year residential rental property. Either way, the owner recovers the cost at ~2.56% or ~3.64% per year — a $750,000 depreciable basis produces roughly $19,000–$27,000 of annual depreciation. Steady. Boring. Not why anyone writes a six-figure check for an STR.

Cost segregation changes the picture by pulling pieces of that building out of the long-life bucket and into shorter MACRS classes:

• 5-year property — personal property components that would be considered §1245 property if they stood alone: appliances, cabinetry, countertops, finish flooring, decorative lighting, window treatments, furniture, electronics, FF&E.
• 7-year property — office furniture, decorative items, certain FF&E categories.
• 15-year land improvements — anything outside the building envelope that is not land itself: pools, hot tubs, fire pits, pergolas, outdoor kitchens, driveways, walkways, retaining walls, fencing, irrigation, outdoor lighting, landscaping.

Every one of those classes has a recovery period of 20 years or less, which is the §168(k)(2) definition of bonus-eligible property. That means every dollar reclassified from 39-year to 5-year or 15-year is a dollar that can be written off in Year 1 at the 100% bonus rate the OBBBA restored in 2025.

Why STRs specifically

Three features make short-term rentals the single best bonus depreciation vehicle in the US tax code. First, under Treas. Reg. §1.469-1T(e)(3)(ii), a rental with an average guest stay of 7 days or less is not treated as a rental activity under §469 — so the losses are not automatically passive. Second, if the owner materially participates (typically clearing the 100-hour "most active participant" test), the losses pass through as nonpassive and can offset W-2 wages and business income. Third, STR builds concentrate spending in exactly the categories cost seg loves: fully furnished interiors, hot tubs, pools, decking, premium appliance packages, decorative lighting.

Pair all three — the STR loophole, material participation, and a well-furnished build — and a cost segregation study turns a $1M purchase into a Year-1 federal tax write-off that often exceeds the owner's annual W-2 income.

What assets get reclassified?

A quality cost segregation study classifies every asset in the property, with photographs, floor plans, and cost estimates. The IRS Cost Segregation Audit Techniques Guide Chapter 4 defines what "quality" means: engineering-based cost estimation, source document retention, and clear classification rationale per asset. Here is the shape of the typical reclassification on a well-furnished single-family STR.

On a well-furnished short-term rental, the 5-year personal property typically runs 14–22% of purchase price, and the 15-year land improvements run 4–10% of purchase price. Combined bonus-eligible share: 18–30%, with cabin-heavy mountain markets concentrating at the top of that range and sparse coastal condos at the bottom. The non-bonus-eligible remainder — the 39- or 27.5-year building shell — depreciates on its normal schedule.

Is it worth it on a single-family home?

For most short-term rentals above roughly $500,000 purchase price, yes — the engineer fee is a small fraction of the first-year tax savings. Below $300,000, the economics compress and a formal study often does not pay off. Between $300,000 and $500,000 depends on build quality, outdoor amenities, and the owner's marginal rate.

The arithmetic is straightforward. According to DepreciMax's 2026 study of 197 short-term rental markets, the median STR carries a bonus-eligible share near 20% of purchase price. A formal engineer-prepared study for a single-family STR runs $3,000–$8,000 as of October 2026 — most national firms quote $5,000–$6,500 for a typical single-family build without unusual complexity. The decision rule:

• Purchase price $500,000+ with Gold or Diamond medal potential: run the study. Year-1 tax savings at the 37% bracket land near $40,000+, versus a $5,000 engineer fee. ROI 8x or better.
• Purchase price $300,000–$500,000 with heavy outdoor amenities (pool, hot tub, outdoor kitchen): probably yes. Pre-screen first with a $99 report to confirm the bonus-eligible share is 20%+ before paying the engineer.
• Purchase price $300,000–$500,000 with basic finishes and no pool/hot tub: run the pre-screen. The economics may land better on the pre-screen alone, with the engineer skipped.
• Purchase price under $300,000: usually not worth a formal study. The pre-purchase estimate carries you through tax prep with your CPA for far less.

Who should skip cost segregation

Two profiles should pass on a formal study:

• Long-term landlords. If the property is held as a traditional rental with 30+ day stays, the §469 passive activity rules apply unless the owner qualifies as a real estate professional under §469(c)(7). For a W-2 investor who cannot meet the REPS 750-hour test, bonus depreciation deductions become passive — offsetting passive income only, not W-2. Cost segregation still accelerates the deductions, but they stack up as suspended passive losses, usable only against future passive income or at eventual disposition. The cash-flow benefit disappears.
• Buyers planning to flip within 2–3 years. Depreciation recapture reclaims the accelerated deductions at sale. A short hold compresses the economic benefit to almost nothing — you take the deduction, then give it back inside the hold period at marginal rates close to what you saved.

Everyone else — the W-2 earner buying a cabin, the semi-retired investor buying a lake house, the couple pivoting into STR investing — fits the cost segregation profile well.

Worked example: 1724 Mohican Dr, South Lake Tahoe CA

Numbers are easier to argue with than paragraphs, so here is the full math on a real property. 1724 Mohican Dr is a mountain-town short-term rental in South Lake Tahoe, California. It analyzed as Gold tier in a DepreciMax Property Report — meaning the bonus-eligible share hit the Gold medal threshold of 22% of purchase price.

The inputs

• Purchase price: $1,000,000
• Land value: ~$250,000 (25% — estimated from mountain-town assessor data patterns)
• Depreciable basis: $750,000
• Bonus-eligible share of purchase price: 22.2% (Gold tier threshold)
• Property type: Furnished single-family cabin, hot tub, deck, mature landscaping
• Placed in service: After January 19, 2025 — qualifies for 100% bonus under OBBBA

Year-1 bonus depreciation math

Year-1 bonus depreciation write-off: ~$222,000. At a 37% federal marginal rate, that converts to approximately $82,140 of first-year federal tax savings, assuming the owner clears the STR loophole and material-participation tests to deduct against ordinary income.

Those figures are a DepreciMax pre-purchase estimate, closely calibrated to a formal cost segregation study. A filed study would detail the 5-year personal property and 15-year land improvements that add up to the bonus-eligible total. The structure of that line-item breakdown — assuming a typical mountain-town cabin build — would look roughly like:

• 5-year personal property: ~16% of purchase price (~$160,000). Finish flooring, custom cabinetry, stone counters, Sub-Zero/Wolf appliance package, decorative lighting, Lutron and Sonos gear, all FF&E conveyed with the property.
• 15-year land improvements: ~6% of purchase price (~$62,000). Hot tub, Trex-grade deck, outdoor stone fireplace, driveway and walkway pavers, mature landscaping, outdoor lighting.

California does not conform to §168(k), so the state return adds back the federal bonus depreciation — the ~$82,140 figure is federal only. Even after the California haircut, a 37% federal bracket owner nets substantially more than the typical $5,000 engineer fee for the formal study.

Can you do it on a property bought last year?

Yes. The IRS allows a lookback cost segregation study on any property placed in service in a prior tax year, using Treas. Reg. §1.168(k)-2 and Form 3115, Application for Change in Accounting Method. The mechanic is elegant: no amended returns required. The §481(a) adjustment calculates the cumulative depreciation the taxpayer would have claimed had the asset classifications been correct from the start, and pulls that entire catch-up into the current tax year as a single deduction.

Example. A short-term rental purchased in April 2025 for $800,000, placed in service in July 2025, with a bonus-eligible share of 22% ($176,000) that was never reclassified. A 2026 lookback study with Form 3115 filed with the 2026 return pulls the full $176,000 catch-up (less the straight-line already claimed) into 2026 as a §481(a) adjustment — no amended 2025 return required.

Two mechanics matter for the lookback election:

• Bonus rate follows the placed-in-service date, not the catch-up year. A property placed in service in 2025 after January 19 falls under the OBBBA 100% permanent regime. A property placed in service in early 2025 before January 19 falls under the 40% phase-down rate. The lookback captures the bonus rate in effect on the original placed-in-service date, not the current year.
• Age ceiling is practical, not statutory. The IRS allows lookback studies on properties placed in service decades ago. In practice, CPAs typically run them on properties under 10 years old, because older properties have already recovered a significant portion of basis through straight-line depreciation and the §481(a) catch-up shrinks.

The lookback election is one of the most under-utilized tax moves in the STR investor playbook. Owners who bought in 2022, 2023, or 2024 — when bonus depreciation was 80%, 60%, or 40% — can still capture meaningful first-year catch-up deductions by filing a lookback study with the current year's return. Combine the lookback with a rental property depreciation baseline review and the catch-up often lands in six figures.

Will it trigger an audit or recapture?

Two separate questions, often conflated. Audit risk and recapture are different mechanics.

Audit posture

A properly documented cost segregation study is not a standalone audit trigger. The IRS Cost Segregation Audit Techniques Guide (updated 2022) formalizes the methodology the agency expects engineers to follow, and the ATG Chapter 4 criteria read like a quality checklist that a competent engineering study already satisfies: engineering-based cost estimation, source document retention, photographs and floor plans, clear classification rationale per asset, and consistency with GAAP depreciation treatment. Studies prepared by qualified engineers — not spreadsheet rule-of-thumb takeoffs — withstand audit consistently.

The audit risk comes from doing cost segregation badly. Single-family owners pulling industry-average percentages off a spreadsheet without supporting documentation have a documented IRS vulnerability. Owners classifying 39-year assets (foundation, framing, roof) as 5-year personal property to inflate the bonus deduction have a documented vulnerability. Owners reporting a cost seg study on Form 4562 without a documentable engineering file to back it have a documented vulnerability. Choose a qualified cost segregation company that produces an engineering-grade report with photographs, floor plans, and defensible asset classifications, and the audit question largely answers itself.

Depreciation recapture at sale

Recapture is the real tax tradeoff on cost segregation. When you sell, the IRS reclaims the accelerated depreciation at specific rates:

• §1245 recapture applies to the 5- and 7-year personal property reclassified by the study. It is taxed at ordinary income rates with a 37% ceiling. On the Tahoe example, the ~$160,000 of 5-year property reclassified would be subject to §1245 recapture up to the full accelerated depreciation claimed.
• §1250 unrecaptured depreciation applies to the 15-year land improvements and the 39-year building structure. It is taxed at a 25% ceiling.
• The remainder of the gain beyond the recapture portion is long-term capital gain at 15% or 20%, assuming more than 12 months of hold.

Recapture does not negate cost segregation — it changes the economics by converting a Year-1 deduction into a deferred tax liability payable at exit. Three levers mitigate it:

• §1031 like-kind exchange. A properly structured exchange defers recapture entirely as part of the deferred gain, rolling the basis forward into the replacement property. The STR community uses 1031 heavily for exactly this reason.
• Long hold periods. The economic value of the Year-1 deduction compounds — invested, deployed into additional properties, or used to retire debt — over the hold. A 10-year hold with the Year-1 savings reinvested at even modest returns substantially outearns the recapture tax at sale.
• Rate arbitrage. Some owners cost-seg while in a high-income W-2 year (37% marginal) and sell in a low-income year (24% or lower), creating positive rate arbitrage on the recapture.

Cost segregation is not a free lunch. It is a timing shift with an exit tax, offset by acceleration and the time value of money. For most STR investors with a 5+ year hold horizon and ordinary income to shelter in the acquisition year, the economics are strongly favorable.

How this fits with the broader STR tax stack

Cost segregation does not stand alone. It is one tool in a stack that includes bonus depreciation, the STR loophole, material participation, and — for pre-purchase pricing — the pre-screen workflow. According to DepreciMax's 2026 study of 197 short-term rental markets, the weighted-median STR carries a bonus-eligible share near 20% of purchase price, with cabin-heavy mountain markets (Smoky Mountains, Big Bear, South Lake Tahoe) running 24–28% and sparse coastal condo markets running 14–18%. The study is the empirical baseline for the market-level math; a cost segregation study is the compliance document for a specific property.

Three places to go deeper from here:

• For the fee-side mechanics — what you actually pay, what you get, how to compare quotes — see our breakdown of cost segregation study cost on a single-family short-term rental.
• For the question of whether a software or template-based alternative is defensible on a smaller property, see our analysis of the diy cost segregation study options and when they hold up to IRS scrutiny.
• For a cross-property view — what counts as bonus depreciation eligible property and where the §168(k) rules do and don't reach — see the eligible-property deep dive.

The ecosystem also depends on getting basis right. Our deep dive on rental property depreciation covers the straight-line baseline cost seg accelerates, and our cost segregation single family home analysis walks the full stack for the detached-SFH case specifically.

Frequently asked questions

What is cost segregation on a short-term rental and how does it work?

Short-term rental cost segregation is an engineering-based study that reclassifies pieces of a rental property out of the long-life 27.5- or 39-year building and into 5-, 7-, and 15-year property. Carpet, appliances, cabinetry, decorative lighting, and furniture typically land in 5-year personal property. Fences, pools, hot tubs, driveways, landscaping, and outdoor kitchens typically land in 15-year land improvements. Everything with a recovery period of 20 years or less qualifies for 100% bonus depreciation under IRS §168(k), which the OBBBA permanently restored for property acquired and placed in service after January 19, 2025. For a short-term rental that clears the material-participation and 7-day average-stay tests, the resulting first-year deduction can offset ordinary W-2 or business income.

What specifically gets reclassified into 5-year and 15-year property?

5-year personal property typically includes: finish flooring (carpet, LVP, decorative tile that is not grouted to structure), cabinetry, stone and quartz countertops, all appliances, decorative lighting, window treatments, built-in shelving, electronics, and any FF&E conveyed with the property. 7-year property covers office furniture, decorative items, and certain FF&E categories. 15-year land improvements typically include: pools, spas and hot tubs, fire pits, outdoor kitchens, pergolas and gazebos, paved driveways and walkways, retaining walls, landscape irrigation, outdoor lighting, and fencing. The 39-year or 27.5-year structural remainder covers foundation, framing, roof, exterior envelope, drywall, central HVAC rough-in, and plumbing rough-in.

Does cost segregation make sense on a single-family short-term rental?

For most short-term rentals above roughly $500,000, yes — the engineer fee is a small fraction of the Year-1 federal tax savings. A $1,000,000 single-family STR in a cabin or mountain-town market with a 20–24% bonus-eligible share generates roughly $200,000–$240,000 in Year-1 deductions, which is roughly $74,000–$89,000 of federal tax savings in the 37% bracket. A formal engineer-prepared study for a single-family STR runs $3,000–$8,000 as of October 2026. The ROI is typically 25x or better. Below $300,000 purchase price the economics compress and a pre-purchase estimate often pays off more than a formal study.

Can I do cost segregation on a property I bought in a prior year?

Yes. The IRS allows a lookback cost segregation study using Form 3115, Change in Accounting Method, with an automatic §481(a) catch-up adjustment that pulls all previously missed depreciation into the current tax year — no amended returns required. For a property placed in service after January 19, 2025, the lookback captures the full 100% bonus depreciation on the reclassified 5- and 15-year property. For a property placed in service during the 40% bonus phase-down window, the catch-up uses the bonus rate in effect on the original placed-in-service date. CPAs typically run lookbacks on properties up to 10 years old, though older is permitted.

Will cost segregation trigger an IRS audit?

A properly documented cost segregation study is not an audit red flag on its own. The IRS Cost Segregation Audit Techniques Guide (ATG), updated 2022, formalizes the methodology and lists the elements of a quality study: engineering-based cost estimation, source document retention, and clear classification rationale per asset. Studies prepared by qualified engineers, with photographs, floor plans, and asset lists, consistently withstand audit. The audit risk comes from doing cost segregation badly — single-family owners pulling rule-of-thumb percentages off a spreadsheet without supporting documentation, which is why the ATG Chapter 4 criteria matter.

What is depreciation recapture if I sell the property later?

When you sell, the IRS reclaims accelerated depreciation at specific recapture rates. §1245 recapture applies to the 5- and 7-year personal property reclassified by the cost seg study — it is taxed at ordinary income rates up to a 37% ceiling. §1250 unrecaptured depreciation applies to the 15-year land improvements and the building structure — it is taxed at a 25% ceiling. The remainder of the gain beyond recapture is long-term capital gain at 15% or 20%. Two mitigation levers exist: a §1031 like-kind exchange defers recapture entirely, and holding the property for a longer timeframe spreads the economic value of the Year-1 deduction over more years. Cost segregation does not eliminate recapture; it accelerates the deduction timing.