Cost Segregation for Multifamily Apartments

Cost segregation for multifamily apartments is an engineering-based tax study that reclassifies a building's components into shorter depreciation lives, so owners of apartment buildings can deduct a large share of their purchase price in the first year. One study covers every unit in the building, which drives the cost per door down as unit count rises — and under current law, the short-life components qualify for 100% first-year bonus depreciation when the property was acquired after January 19, 2025.

Why Multifamily Buildings Are Ideal for Cost Segregation

Apartment buildings are the best candidate for what cost segregation is for a simple reason: repetition. A single-family investor needs a separate study for every house. An apartment owner gets every unit in one analysis — 12 kitchens, 12 sets of appliances, 12 carpets, all quantified once. The more units, the lower the effective cost per door.

Typical reclassification results for multifamily fall in the 20–30% range into 5-, 7-, and 15-year property, meaning roughly a fifth to nearly a third of the depreciable basis moves off the 27.5-year schedule. The 27.5-year clock still applies to the building shell — that's the correct MACRS recovery period for residential rental property under §168 — but everything that isn't structure, land, or part of the permanent building systems gets a shorter life.

Scale matters on the study side too. Studies are priced largely on engineering time, and identifying one appliance package across 24 identical units costs far less than 24 separate analyses. That is why multifamily is the asset class where the study's return on investment is hardest to argue against — a single engagement routinely produces six figures of accelerated deductions.

What Gets Reclassified in an Apartment Building

A cost segregation engineer walks the property and the construction records and sorts every component into its IRS-recognized bucket:

A note on laundry rooms, clubhouses, and pools: these common areas are some of the richest sources of reclassification in multifamily. Site work around the building — paving, fencing, lighting, landscaping — is almost entirely 15-year property, and it often represents a larger share of the basis than investors expect.

Everything in the 5-, 7-, and 15-year buckets is eligible for 100% bonus depreciation under current law when the property was acquired and placed in service after January 19, 2025 (IRS Notice 2026-11 made the 100% rate permanent). The 27.5-year structure is not bonus-eligible because its recovery period exceeds the 20-year threshold in §168(k).

Worked Example: $2 Million, 12-Unit Building

Say you buy a 12-unit building for $2,000,000 and place it in service in 2026.

• Land allocation (non-depreciable): 20% = $400,000
• Depreciable basis: $1,600,000

Without a study, the whole $1.6 million depreciates straight-line over 27.5 years: about $58,200 of deduction in year one.

With a study at typical multifamily reclassification rates: That is roughly $493,000 more depreciation in the first year than the no-study path. At a 32% marginal federal rate, the incremental year-one tax savings are about $158,000 — on a property that cost $2 million. You haven't created new deductions; you've moved them forward, and a dollar of deduction today is worth more than a dollar of deduction in 2040.

One Study, Every Unit — And Look-Backs Count

The "one study covers all units" rule applies to properties you already own, too. If you bought your building years ago and never did a study, a look-back cost segregation study lets you claim the missed depreciation as a catch-up deduction on your current return via Form 3115 — no amended returns. Multifamily look-backs are especially lucrative because several years of short-life depreciation land in a single tax year.

Worth noting: the 2025 OBBBA change works in your favor on look-backs as well. For property acquired before January 19, 2025, the bonus rate that applies to the catch-up year follows the law in effect for that property's placed-in-service year — but the permanent 100% rate going forward means newly acquired buildings get the full benefit with no phase-down on the horizon.

Syndications and K-1s

If you own through a syndication or partnership, the study's results flow into the entity's depreciation schedule and out to investors on their K-1s as paper losses. For passive investors, those losses generally offset passive income (and can be carried forward), not W-2 income — the classic K-1 result is several years of tax-sheltered distributions. Active operators who qualify as real estate professionals under §469(c)(7) face a different, more favorable set of rules. Either way, this is squarely talk-to-your-CPA territory before you underwrite a deal around the losses.

Plan for the Exit: Depreciation Recapture

Accelerated depreciation has a cost at sale: the IRS wants some of it back. Short-life property you depreciated is subject to depreciation recapture when you sell, taxed at up to 25% for unrecaptured §1250 gain, while the 27.5-year structure's depreciation faces its own rules. This doesn't erase the benefit — time value of money still wins — but run the exit math before you sell, and know that 1031 exchanges and step-up at death are the standard ways investors manage it.

When It Doesn't Make Sense

Cost segregation isn't automatic. Skip it (or run the numbers hard) when the depreciable basis is small — duplexes and triplexes under roughly $300,000 of basis often don't clear the study cost — when you plan to flip within a couple of years with no 1031 exit lined up, or when you can't use the losses this year and have no passive income to absorb them. The fundamentals of cost segregation for residential rentals apply here too: multifamily is the same strategy, just with better economics per door.

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Ready to see what your building qualifies for? ROOM42 runs IRS-compliant, engineering-based cost segregation studies for multifamily owners — one study covers every unit, starting at $525 per unit. Get your free estimate at room42.io.