Arizona is one of a small number of states with a flat individual income tax, a rate lawmakers cut to 2.5% in 2023 — the lowest flat rate of any state that taxes income at all. That is a favorable backdrop for rental owners, but it also changes the cost-segregation math in a way many owners do not expect: Arizona's own tax code does not follow the federal government's 100% bonus depreciation rules. Investors who own property in the state's established short-term-rental markets — Phoenix and Scottsdale, Sedona, Tucson, Flagstaff, and Lake Havasu City — still capture the full federal acceleration; they just need to understand where the state diverges before their CPA files the return.
Apex Reserve Group is an Irvine, California-based firm that performs engineering-based cost segregation studies for real estate investors nationwide, including throughout Arizona. Everything on this page is general educational information, not tax or legal advice — confirm how these rules apply to your specific property and return with your own CPA.
Why Cost Segregation Pays Off in Arizona
Arizona moved to a flat 2.5% individual income tax rate in 2023, replacing its old graduated brackets and giving the state the lowest flat income-tax rate in the nation among states that tax income. That single fact changes how much weight the federal half of a cost segregation study carries for an Arizona property owner, relative to an investor in a high-tax state.
Here is the state-specific detail that matters most, and the one most worth confirming with your CPA: Arizona does not conform to federal bonus depreciation under Internal Revenue Code Section 168(k). Under Arizona Revised Statutes 43-1021 and 43-1022, a taxpayer who claims federal bonus depreciation must add that amount back into Arizona taxable income, then take a subtraction equal to the depreciation that would have applied had the taxpayer not elected bonus depreciation — in other words, standard MACRS spread over the asset's normal recovery period. Arizona's 2026 conformity legislation (HB 4168, signed into law in June 2026) kept this addback in place for Section 168(k) and extended a similar decoupling to the new Section 168(n) qualified production property allowance created by the One Big Beautiful Bill Act.
In practice, this means the accelerated first-year write-off from a cost segregation study appears in full on your federal return, while on your Arizona return the same reclassified assets depreciate on their ordinary schedule instead of all at once. Because Arizona's rate is only 2.5% flat, the dollar value of that state-level timing difference is comparatively modest next to the federal benefit, which is calculated at your regular federal bracket, up to 37%. Add Arizona's low property tax burden — an effective rate of roughly 0.4% to 0.6%, well under the national average of about 0.9% to 1.1% — and a deep bench of short-term-rental markets in Phoenix and Scottsdale, Sedona, Tucson, Flagstaff, and Lake Havasu City, and the overall carrying cost of Arizona rental property is low even before cost segregation enters the picture.
How a Cost Segregation Study Works
A cost segregation study is an engineering-based review of a building's construction records, appraisal, and site conditions. Rather than depreciating an entire residential rental over 27.5 years (39 years for commercial property) as a single asset, engineers separate out components — flooring, cabinetry, built-in appliances, specialty electrical and plumbing, decking, fencing, and land improvements such as landscaping and paving — that the tax code actually treats as 5-, 7-, or 15-year property.
Under the One Big Beautiful Bill Act, signed into law in July 2025, Congress permanently restored 100% bonus depreciation for qualifying property acquired and placed in service after January 19, 2025 (or, for self-constructed property, where construction began after that date). That means any component a study reclassifies into the 5-, 7-, or 15-year categories can, on the federal return, be deducted in full in the year it is placed in service rather than depreciated gradually over decades. One nuance worth flagging for your CPA: property acquired under a binding contract signed before January 19, 2025 but placed in service later can instead remain subject to the prior law's phase-down schedule, so the placed-in-service date alone does not always control — the acquisition date matters too.
An Arizona Cost Segregation Example
The following is a hypothetical for illustration only, not a projection for any actual property. Your results depend on your property's cost basis, its components, and your personal tax situation.
Suppose an investor buys a short-term rental near Sedona for $600,000. After allocating $100,000 to land, which is never depreciable, the depreciable building basis is $500,000.
- Without cost segregation: the full $500,000 depreciates straight-line over 27.5 years, for a deduction of roughly $18,200 per year.
- With a cost segregation study: an engineering review identifies, hypothetically, $125,000 of components — flooring, appliances, specialty electrical, decking, and landscaping — that qualify for 5-, 7-, or 15-year treatment.
- On the federal return: under 100% bonus depreciation, that full $125,000 could be deducted in year one instead of over decades.
- On the Arizona return: because Arizona decouples from Section 168(k), that same $125,000 is added back and instead depreciated on standard MACRS over its 5-, 7-, or 15-year life, so the Arizona deduction in year one is only a fraction of the federal figure. Given Arizona's 2.5% flat rate, that state-level timing difference is modest in dollar terms next to the federal deduction.
Again, these numbers are illustrative only. An actual study would itemize your specific property, and your CPA would apply your real federal and Arizona tax figures.
Already Own Your Arizona Property? The Look-Back Study
If you already own Arizona rental property and have been depreciating it on a standard schedule, you have not missed your window. A look-back study applies cost segregation to a property after it has already been placed in service. Rather than amending every prior-year return, your CPA files IRS Form 3115 (Application for Change in Accounting Method), which converts the difference between what was actually depreciated and what should have been depreciated into a single Section 481(a) adjustment — claimed as a one-time catch-up deduction in the current tax year, with no amended returns required. On the Arizona side, the same addback-and-MACRS treatment described above still applies to the federal bonus portion of that catch-up.
Who Should Consider Cost Segregation in Arizona
Cost segregation tends to make the most sense for:
- Short-term rental and Airbnb hosts in Arizona's established vacation-rental markets, including Phoenix and Scottsdale, Sedona, Tucson, Flagstaff, and Lake Havasu City.
- Long-term rental property owners who want to accelerate federal depreciation even without using the short-term-rental strategy described below.
- Recent buyers, or owners who have completed a major renovation, since a new cost basis or significant improvement creates fresh components to classify.
- High-earning W-2 or 1099 taxpayers exploring the short-term-rental material-participation strategy: if a property's average guest stay is 7 days or less and the owner materially participates in operating it, the rental can be treated as non-passive under IRS rules, which may let depreciation losses from cost segregation offset active income. This hinges on meeting specific material-participation and average-stay tests, so it should be planned with a CPA before the tax year closes.