Duplex · Triplex · Fourplex

Cost Segregation Study for Duplex Owners

Multi-unit properties multiply the benefit of cost segregation — every unit contains its own depreciable components. Under the 2026 OBBBA, 100% of reclassified assets are deductible in year one.

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Duplexes and small multi-family properties multiply depreciable components across every unit.

Each unit in a duplex or fourplex contains its own appliances, flooring, cabinetry, electrical panels, plumbing fixtures, and HVAC components — all reclassifiable as 5-year property. Common-area landscaping, parking, fencing, and exterior lighting qualify as 15-year land improvements. In a typical 2–4 unit property, 24–32% of the purchase price can be accelerated.

Most multi-family owners don't realize they're leaving $40,000–$150,000+ in first-year deductions on the table.

Why duplexes and fourplexes produce outsized cost seg results.

The cost segregation advantage scales with unit count. A fourplex has four sets of kitchens, four sets of bathrooms, four HVAC systems — each containing components that reclassify from 27.5 years to 5 years.

Per-Unit Component Multiplier
IRS Cost Segregation Audit Techniques Guide · Chapter 7.2

A 12-unit building studied correctly can unlock six figures in accelerated deductions in year one. Even a simple duplex typically produces $40,000–$65,000 in reclassified assets.

For real estate professionals who meet the 750-hour test under IRC §469(c)(7), these accelerated losses can offset W-2 and business income without passive activity limitations.

Typical asset breakdown for a 2–4 unit property

Our analysis identifies every qualifying component in every unit — not just common areas:

Asset CategoryRecovery PeriodExamples% of Basis
Personal Property5 yearsPer-unit: appliances, cabinetry, flooring, fixtures, electrical, plumbing20–24%
Land Improvements15 yearsCommon area: parking, landscaping, fencing, exterior lighting, sidewalks8–10%
Building Components27.5 yearsStructural framing, foundation, roof, exterior walls55–70%
LandNon-depreciableLot value15–25%

On a $1.5M fourplex, that typically means $350K–$500K in accelerated deductions available in year one.

Material Participation & Real Estate Professional Status

How you use your depreciation losses depends on your participation level and how the property is rented. Under IRC §469 (unchanged by OBBBA), there are three paths to using cost segregation losses against your active income:

Path 1: Short-Term Rental Loophole (No REPS Required)
IRC §469(j)(8) · Treas. Reg. §1.469-1T(e)(3)(ii)(A)

If your average guest stay is 7 days or fewer (Airbnb, VRBO, vacation rental), the activity is not treated as a rental activity. Losses can offset W-2 and business income — provided you materially participate. No REPS qualification needed.

Path 2: Real Estate Professional Status (REPS)
IRC §469(c)(7) · 750-hour test + 50% test

For long-term rentals, qualify as a Real Estate Professional to treat rental losses as non-passive. You must: (1) spend more than 750 hours per year in real property trades or businesses, and (2) that time must represent more than 50% of your total working hours. One spouse can qualify for a joint return.

Path 3: $25,000 Rental Loss Allowance
IRC §469(i) · Active participation

If you actively participate in your rental (make management decisions, approve tenants, authorize repairs) and your AGI is under $150,000, you can deduct up to $25,000 in rental losses against active income. Phases out between $100K–$150K AGI. Excess losses carry forward.

What changed in 2026: The OBBBA permanently restored 100% bonus depreciation under IRC §168(k) for qualified property acquired after January 19, 2025. This means a cost segregation study now creates larger first-year paper losses than ever — making the path you use to deduct those losses more important than ever. The passive activity rules under §469 remain unchanged.

Bottom line: If you qualify through any of these three paths, a cost segregation study combined with 100% bonus depreciation can produce $30,000–$150,000+ in first-year tax savings on a single property. We'll confirm your eligibility on a free 15-minute call before you commit to anything.

Your duplex is sitting on untapped deductions.

Your property is generating tax savings right now. The only difference is whether you're claiming them or leaving them for the IRS.

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