Is A Cost Segregation Study Worth It?
The study is the easy part. The question that actually decides whether it pays is one most people are never asked.
By Nneka Nwobi, CPA, MBA, Founder & CEO
Last updated
The Answer, First
A cost segregation study will almost always find accelerated deductions. Whether you can actually use them this year is a completely separate question, and it is decided by the passive activity loss rules in Section 469, not by the study.
This is the part that gets skipped. A firm sells you an engineering study, the study does its job, and the deductions land on your return as suspended passive losses you cannot touch. Nothing was done wrong. The gate was simply never checked before the invoice was paid.
What The Study Does
A building bought as one asset depreciates slowly. A cost segregation study takes it apart and reclassifies components into 5, 7 and 15 year property: fixtures, certain electrical and plumbing serving equipment, flooring, cabinetry, land improvements and similar. Those shorter-life components then depreciate far faster than the building shell.
It requires an engineering-based study with real documentation. This is not a spreadsheet exercise, and a thinly supported allocation is exactly the kind of position that does not hold up.
Why 2026 Changed The Maths
The One Big Beautiful Bill Act restored 100 percent bonus depreciation for qualified property acquired and placed in service after 19 January 2025, and Treasury and the IRS have issued guidance on the amended first-year depreciation rules.
That matters because bonus depreciation is what turns a study from a timing tweak into a large current-year deduction. Under the phase-down the components a study identified were worth progressively less. At 100 percent they can often be expensed immediately. The upside is materially bigger than it was two years ago, which is also why the gate below matters more, not less.
The Gate: Section 469
Rental activity is generally passive. Passive losses can only offset passive income. If you are a high earner with W-2 or business income and a rental property, a large paper loss from a cost segregation study does not reduce that income. It sits suspended until you have passive income or you dispose of the activity.
So before commissioning a study, the question is not how much will it find. It is which door out of the passive rules do I have. There are three.
Door 1
Real estate professional status
More than 750 hours a year in real property trades or businesses, and more than half of all your personal services for the year in them. Both tests, not either. Hours must be documented as you go.
Door 2
The short-term rental route
Short-term rentals can fall outside the passive rental rules where the average rental period and personal services tests are met and you materially participate. This does not require real estate professional status, which is why it is often the more realistic door for a full-time professional.
Door 3
Existing passive income
If you already have passive income from other activities, passive losses can offset it. No status test required. This is the quietest of the three and the most often overlooked.
If none of the three applies to you, a study is still not necessarily wrong. It just means you are buying future benefit, not a current-year deduction, and it should be priced and timed on that basis.
The study is not the decision. I have seen owners pay for a beautiful engineering report that produced a deduction they had no way to use for years. Work out which door you have through the passive rules first. If you have one, the study is often excellent value. If you do not, you have bought timing you cannot spend.
The Hours Tests Are Where These Claims Die
Real estate professional status requires more than 750 hours a year in real property trades or businesses, and more than half of all your personal services for the year in them. Both tests. A physician working full time in a practice will struggle with the second one no matter how many hours they put into property, which is why the status is frequently claimed by the lower-earning or non-employed spouse instead.
Whatever the route, hours have to be recorded contemporaneously. A log built at filing time, from memory, is the single weakest position in this entire area. Short-term rental material participation carries the same documentation burden.
When A Study Is Not Worth It
- The building basis is small enough that the study fee eats most of the benefit
- You expect to sell in the near term and depreciation recapture will claw it back
- There is no viable route through the passive activity loss rules
- Your marginal rate this year is lower than the rate you reasonably expect later
That last one is the least discussed and the most expensive to get wrong. Accelerating a deduction into a year where your rate is low, to lose it in a year when your rate is high, is a bad trade dressed up as a tax saving.
Frequently Asked Questions
- Is a cost segregation study worth it?
- The study will almost always find accelerated deductions. Whether you can use them in the current year is a separate question decided by the passive activity loss rules in Section 469, not by the study. For a passive investor with no passive income and no qualifying status, the deductions are real but suspended, and the study buys timing you cannot access yet.
- What does a cost segregation study actually do?
- It reclassifies components of a building out of the long depreciation life and into 5, 7 and 15 year classes. Those shorter-life components then depreciate much faster, and with 100 percent bonus depreciation restored they can often be expensed immediately.
- Did the One Big Beautiful Bill Act change this?
- Yes, materially. OBBBA restored 100 percent bonus depreciation for qualified property acquired and placed in service after 19 January 2025, and the IRS has issued guidance on the amended first-year depreciation rules. That makes the components a study identifies considerably more valuable than they were under the phase-down.
- How do I actually use the losses?
- There are three doors. Qualify as a real estate professional, which requires more than 750 hours a year in real property trades or businesses and more than half of your total personal services in them. Or meet the short-term rental tests, where the average rental period and personal services tests are met and you materially participate. Or have other passive income for the losses to offset.
- Can my spouse qualify for real estate professional status instead of me?
- Yes, and for high-earning households that is often the practical route, because the hours tests are demanding for someone already working full time in another profession. The hours have to be genuine and documented contemporaneously, not reconstructed at filing.
- When is a cost segregation study not worth it?
- When the building basis is small enough that the study fee eats the benefit, when you plan to sell soon and depreciation recapture will claw it back, when you have no way through the passive loss rules, or when your current-year marginal rate is lower than the rate you expect later. Accelerating a deduction into a low-rate year is a bad trade.
Check The Gate Before You Buy The Study
We will tell you which door through the passive rules you actually have, and whether a study makes sense for your position this year or a later one. That is a Smart Tax Review at $97, credited toward any work that follows.
Book a Smart Tax ReviewThis page is general information about federal tax rules, not tax advice for any specific taxpayer, and no client relationship is created by reading it. Tax outcomes depend on facts we have not reviewed, and figures, thresholds and limits change. Entity formation and any governing documents require a licensed attorney. RCN CPAs & Business Advisors, Kennesaw, Georgia.