Cost Segregation, Explained for Small Rental Owners

Residential rental buildings are normally depreciated over 27.5 years. A cost segregation study breaks the purchase into components, some of which can be depreciated much faster. That can shift deductions into the early years of ownership. Whether it helps you depends on your income, your tax situation, and the size of the property, so treat this as background for a conversation with a CPA.

What the study does

An engineer or specialist reviews the property and assigns parts of the cost to categories with shorter recovery periods:

• 5-year or 7-year property: appliances, carpet, some fixtures, certain electrical and plumbing serving specific equipment.
• 15-year land improvements: driveways, fencing, landscaping, sidewalks, outdoor lighting.
• 27.5-year building: the structure itself.

Land is never depreciated, so the first step is always a reasonable land-versus-building split.

Bonus depreciation

Assets with recovery periods of 20 years or less may qualify for bonus depreciation, which lets you deduct a large share of their cost in the first year. Federal bonus depreciation rules have changed several times in recent years, including legislation in 2025 affecting the percentage available. Confirm the current rule for your placed-in-service date with your tax professional rather than relying on any article.

A simple illustration

Imagine a $300,000 small multifamily purchase with $60,000 allocated to land. Straight-line depreciation on the remaining $240,000 over 27.5 years is roughly $8,700 a year. A study might reclassify, say, $50,000 into 5-, 7-, and 15-year property. With accelerated methods or bonus depreciation, much of that $50,000 could be deducted early instead of over decades. The actual split depends on the property and the study.

The passive loss catch

Rental losses are generally passive. For many W-2 earners, passive losses can only offset passive income, with a limited exception for active participants below certain income levels and broader treatment for qualifying real estate professionals. If you cannot use the losses this year, they carry forward. A big first-year deduction is only valuable if you can actually apply it.

Cost versus benefit

Full engineering studies for larger buildings can run several thousand dollars. Lower-cost studies and software options exist for single-family and small rentals. As a rough screen, owners often find the math works better on higher-priced properties, or when they have passive income or qualifying status to absorb the deductions. Your CPA can model the net present value of the accelerated deductions against the fee.

Recapture at sale

Faster depreciation now means a lower tax basis later. When you sell, depreciation is generally recaptured and taxed, and the portion tied to short-life personal property can be taxed at ordinary income rates. A 1031 exchange can defer that, but deferral is not elimination. Plan the exit before you accelerate the deductions.

Already own the property?

A study can often be done in a later year, with a catch-up adjustment for missed depreciation filed through an accounting method change. Ask your CPA whether that makes sense for your holding period.

Bottom line

Cost segregation is a timing tool. It can improve early cash flow after taxes for the right owner, but it does not make a weak property good. Underwrite the deal before taxes first, then let a qualified tax professional decide whether a study adds value.