Quick Answer

Cost segregation for properties over $1M is the single most underused depreciation strategy in commercial and residential real estate investing. On a $1.2 million property, a properly executed cost segregation study can reclassify 20% to 40% of the building’s cost into 5-year, 7-year, and 15-year asset categories instead of the standard 27.5-year or 39-year recovery period. That reclassification, combined with 100% bonus depreciation under the One Big Beautiful Bill Act (OBBBA), can generate $80,000 to $180,000 in first-year tax deductions. For California investors facing a combined federal and state marginal rate above 50%, those deductions translate into $40,000 to $90,000 in real tax savings in year one alone.

Why Most Investors With Million-Dollar Properties Leave $80,000 on the Table

Here is the uncomfortable truth about owning investment property worth $1 million or more: the IRS gives you permission to accelerate tens of thousands of dollars in depreciation deductions, and most investors never take advantage of it. They buy the property, hand the closing documents to their CPA, and accept a straight-line depreciation schedule that spreads the deduction evenly over 27.5 years for residential or 39 years for commercial buildings. That approach is not wrong, but it is the slowest, most expensive way to depreciate a high-value asset.

Cost segregation is an engineering-based study that breaks a building into its individual components and reclassifies them into shorter depreciation categories. Instead of treating the entire building as a single 27.5-year or 39-year asset, the study identifies personal property (5-year and 7-year assets like carpeting, appliances, cabinetry, decorative fixtures, and specialized electrical) and land improvements (15-year assets like parking lots, landscaping, sidewalks, and fencing). Those shorter-lived assets qualify for bonus depreciation, which under OBBBA has been restored to 100% for assets placed in service after January 20, 2025.

On a $1.5 million apartment complex with a $200,000 land allocation, the depreciable basis is $1.3 million. Standard straight-line depreciation gives you roughly $47,272 per year. A cost segregation study that reclassifies 30% of the depreciable basis into short-lived categories would move $390,000 into accelerated depreciation. With 100% bonus depreciation, you deduct that $390,000 in year one instead of spreading it over decades. The remaining $910,000 continues depreciating over 27.5 years at $33,090 per year. Your first-year total depreciation jumps from $47,272 to $423,090. That is an additional $375,818 in deductions.

At a combined federal and California marginal rate of 50.3% (37% federal plus 13.3% state), that extra deduction saves you approximately $189,036 in taxes. Subtract the $8,000 to $15,000 cost of the study, and you are looking at a net tax benefit exceeding $174,000 in the first year. That is not a theoretical number. That is how cost segregation for properties over $1M actually works when executed correctly.

How Cost Segregation Works on Properties Over $1 Million

The IRS does not require a cost segregation study, but it explicitly endorses the practice. The IRS Audit Techniques Guide for Cost Segregation (ATG) outlines the methodology and confirms that engineers and tax professionals can reclassify building components into shorter recovery periods. The key IRS guidance comes from IRS Publication 946, which details the Modified Accelerated Cost Recovery System (MACRS) depreciation rules, and Revenue Procedure 87-56, which establishes the class lives for different asset types.

A qualified cost segregation study involves a physical inspection of the property by an engineer or construction professional, a detailed analysis of construction costs, and a report that identifies each building component and assigns it to the correct asset class. The four main categories are:

• 5-Year Property: Carpeting, appliances, decorative lighting, certain electrical outlets, window treatments, signage, and specialized millwork. Typically 8% to 15% of building cost.
• 7-Year Property: Office furniture, certain equipment, and specialized fixtures permanently attached to the building. Usually 2% to 5% of building cost.
• 15-Year Property: Parking lots, sidewalks, landscaping, fencing, drainage systems, exterior lighting, and site utilities. Often 10% to 20% of building cost.
• 27.5-Year or 39-Year Property: The structural building shell, HVAC systems, plumbing, and standard electrical. This is whatever remains after the shorter-lived assets are separated out.

For a deeper breakdown of every asset category and California-specific strategies, explore our complete cost segregation guide for California investors. The typical result for properties over $1 million is that 20% to 40% of the depreciable basis gets reclassified into accelerated categories. That percentage varies by property type. Apartment complexes and hotels tend to have higher reclassification rates (30% to 40%) because of their heavy use of personal property like furnishings and decorative finishes. Office buildings and warehouses tend to be lower (15% to 25%) because more of the cost sits in structural components.

Many real estate investors assume cost segregation only makes sense for brand-new construction. That is false. The IRS allows you to perform a cost segregation study on properties you already own and take a catch-up deduction in the current year under IRC Section 481(a). This is called a “look-back” study, and it does not require filing amended returns. You file Form 3115 (Application for Change in Accounting Method) and take the entire cumulative catch-up deduction in one tax year. On a property purchased three years ago, this catch-up deduction can exceed $200,000.

The Five Costliest Mistakes Investors Make With Cost Segregation on High-Value Properties

Mistake 1: Skipping the Study Because “My CPA Handles Depreciation”

Standard CPAs depreciate the entire building on a straight-line basis. They are not wrong, but they are leaving money on the table. Cost segregation requires engineering expertise, not just accounting knowledge. Your CPA files the returns. A cost segregation firm identifies the accelerated deductions. If your CPA has never recommended a study on a property worth over $1 million, you are almost certainly overpaying your taxes.

Mistake 2: Using a Desktop Study Instead of an Engineering-Based Study

Some firms offer “desktop” or “template” cost segregation studies that use percentage estimates without physically inspecting the property. The IRS Audit Techniques Guide specifically states that quality studies should include detailed, contemporaneous records and a site visit. If the IRS audits your return and your study lacks an engineering report with a physical inspection, the reclassifications can be disallowed. On a $1.5 million property, that disallowance could trigger $60,000 or more in back taxes plus penalties and interest.

Mistake 3: Ignoring Land Improvements

Investors focus on the building itself and forget about the 15-year property sitting outside. Parking lots, landscaping, retaining walls, storm drainage, exterior lighting, and fencing are all 15-year assets that qualify for bonus depreciation. On a commercial property with a large parking area, land improvements can represent 15% to 20% of total project cost. Missing these deductions on a $2 million property could cost you $40,000 to $80,000 in lost first-year tax savings.

Mistake 4: Failing to Account for California Bonus Depreciation Nonconformity

This is the trap that catches almost every out-of-state investor and many California-based ones too. California does not conform to federal bonus depreciation under Revenue and Taxation Code Sections 17250 and 24356. That means the 100% bonus depreciation you claim on your federal return is not allowed on your California return. You must maintain dual depreciation schedules: one for federal (with bonus depreciation) and one for California (straight-line only). If you claim bonus depreciation on your California return, the Franchise Tax Board (FTB) will send you a notice and assess additional tax plus a 20% accuracy-related penalty. Our cost segregation services include California-specific dual depreciation tracking to prevent this exact problem.

Mistake 5: Not Coordinating With Your Exit Strategy

Accelerated depreciation reduces your tax basis in the property. When you sell, that lower basis means higher taxable gain. If you plan to sell the property in three years without a 1031 exchange, the depreciation recapture under IRC Section 1250 (taxed at up to 25% for real property) and Section 1245 (taxed as ordinary income for personal property) can partially offset your earlier savings. Smart investors use cost segregation in coordination with a 1031 exchange strategy to defer both the capital gain and the depreciation recapture indefinitely. If you want to estimate the tax impact of a future sale, run your numbers through this capital gains tax calculator to see how depreciation recapture affects your bottom line.

OBBBA Changes That Supercharge Cost Segregation in 2026

The One Big Beautiful Bill Act (OBBBA), signed into law in 2025, made several changes that directly impact cost segregation for properties over $1M. Here is what matters:

100% Bonus Depreciation Is Back

Before OBBBA, bonus depreciation was phasing down: 80% in 2023, 60% in 2024, 40% in 2025 under the original Tax Cuts and Jobs Act schedule. OBBBA restored 100% bonus depreciation retroactively for assets placed in service after January 20, 2025. This means every dollar reclassified through cost segregation into 5-year, 7-year, or 15-year categories can be deducted in full in year one. For a $1.5 million property with $400,000 in reclassified assets, that is a $400,000 deduction instead of $240,000 (at the old 60% rate).

Section 179 Increased to $2.5 Million

Section 179 allows you to expense qualifying assets up to $2.5 million (with a phase-out beginning at $4.27 million). While Section 179 has limitations for rental property (it cannot be used for residential rental property placed in service after 2017 for certain components), it remains valuable for commercial properties and mixed-use buildings where the commercial portion qualifies.

$40,000 SALT Cap With AB 150 PTE Bypass

The SALT deduction cap increased from $10,000 to $40,000 under OBBBA. California investors operating through pass-through entities (LLCs or S Corps) can further bypass this cap using the AB 150 Pass-Through Entity (PTE) elective tax. The PTE election allows the entity to pay state taxes at the entity level and claim a dollar-for-dollar federal credit, effectively deducting California’s 13.3% income tax above the SALT cap. When combined with cost segregation deductions, this stacking strategy can reduce your effective tax rate below 30% on rental income that would otherwise be taxed above 50%.

Qualified Business Income (QBI) Deduction Made Permanent

OBBBA permanently extended the 20% QBI deduction under IRC Section 199A. Rental real estate income generally qualifies for QBI if you meet the safe harbor requirements under Revenue Procedure 2019-38 (250 hours of rental services per year, separate books and records, contemporaneous logs). Combined with cost segregation, QBI can reduce the taxable portion of your rental income by an additional 20% after depreciation deductions. On $100,000 of net rental income after cost segregation deductions, QBI saves you another $7,400 to $8,800 depending on your bracket.

California-Specific Cost Segregation Traps

Dual Depreciation Schedule Requirement

This bears repeating because it is the single biggest compliance failure we see. California does not allow bonus depreciation. Period. Under R&TC Sections 17250 and 24356, you must maintain a separate California depreciation schedule that uses straight-line depreciation over the full MACRS recovery period. Your federal return shows the accelerated deduction. Your California Form 540 (individual), Form 568 (LLC), or Form 100S (S Corp) shows the slower straight-line deduction. The difference creates a timing adjustment that must be tracked for the entire life of the property.

The $800 Minimum Franchise Tax

Every LLC or corporation holding California real estate owes the $800 minimum franchise tax annually under R&TC Section 17941, regardless of whether the entity has income. If you hold multiple properties in separate LLCs (which is common for asset protection), each LLC owes $800 per year. This is a minor cost relative to the tax savings from cost segregation, but it must be factored into your entity structuring analysis.

California’s 13.3% Top Rate With No Capital Gains Preference

Unlike the federal system, which taxes long-term capital gains at 0%, 15%, or 20%, California taxes capital gains as ordinary income at rates up to 13.3%. When you sell a property with accelerated depreciation, the recapture and gain are taxed at California’s full rate. This makes the 1031 exchange strategy even more critical for California investors using cost segregation. Without a 1031 exchange, California recapture taxes alone can reach 13.3% of the reclassified personal property, plus the 25% federal recapture rate, for a combined recapture tax rate approaching 38.3%.

Gross Receipts Fee for LLCs

California LLCs with total income (including gross rental receipts, not net income) over $250,000 owe an additional gross receipts fee under R&TC Section 17942. The fee ranges from $900 (at $250,000) to $11,790 (at $5 million or more). This fee is not deductible for California purposes. Investors with multiple high-value rental properties held in a single LLC can trigger this fee based on gross rents, not profits. Structuring each property in a separate LLC can reduce or eliminate this fee, though you must weigh that against the additional $800 franchise tax per entity.

KDA Case Study: San Jose Apartment Complex Owner

Marcus, a San Jose-based investor, purchased a 12-unit apartment complex in 2023 for $2.4 million. His previous CPA had been depreciating the entire building on a straight-line basis over 27.5 years, generating approximately $72,000 per year in depreciation deductions. Marcus came to KDA in early 2026 after hearing about the OBBBA restoration of 100% bonus depreciation.

Our team ordered an engineering-based cost segregation study on the property. The study identified $168,000 in 5-year personal property (appliances, carpeting, cabinetry, decorative light fixtures, window treatments), $48,000 in 7-year property (specialized fixtures and equipment), and $264,000 in 15-year land improvements (parking lot, landscaping, exterior lighting, fencing, sidewalks). Total reclassified assets: $480,000, representing 25% of the depreciable basis.

Because Marcus had owned the property since 2023, we filed Form 3115 to claim a Section 481(a) catch-up adjustment. The cumulative accelerated depreciation he had missed over the prior three years, plus the 100% bonus depreciation on the reclassified assets, generated a one-time deduction of $412,000. At his combined federal and California marginal rate of 49.3%, that deduction saved him $203,116 in taxes in 2026. After subtracting the $12,000 study cost and $4,800 in KDA advisory fees, Marcus netted $186,316 in first-year tax savings. That is an 11.1x return on investment. Over five years, including the ongoing depreciation benefit and QBI optimization, his projected savings total $347,000.

We also set up dual depreciation schedules to keep Marcus compliant with California’s bonus depreciation nonconformity rules, activated the AB 150 PTE election on his LLC to bypass the SALT cap, and coordinated his exit strategy with a 1031 exchange timeline to defer recapture taxes when he eventually sells.

Ready to see how we can help you? Explore more success stories on our case studies page to discover proven strategies that have saved our clients thousands in taxes.

Who Should Order a Cost Segregation Study?

Not every property qualifies for a cost segregation study that justifies the cost. Here is the decision framework:

Property Value	Study Cost	Expected First-Year Benefit	Recommendation
Under $500,000	$5,000 to $8,000	$15,000 to $35,000	Consider if holding long-term
$500,000 to $1,000,000	$6,000 to $10,000	$35,000 to $80,000	Strongly recommended
$1,000,000 to $3,000,000	$8,000 to $15,000	$80,000 to $200,000	Almost always worth it
$3,000,000 to $10,000,000	$12,000 to $25,000	$200,000 to $600,000	Mandatory for tax optimization
Over $10,000,000	$20,000 to $50,000	$600,000+	Non-negotiable

The break-even point for a cost segregation study on properties over $1 million is almost always met in the first year. A $12,000 study that generates $120,000 in first-year tax savings delivers a 10x return before you factor in the time value of money from deferring those taxes.

Should You Order a Study on Property You Already Own?

Yes. The look-back study with Form 3115 allows you to claim all missed accelerated depreciation in the current year without amending prior returns. This is one of the few IRS provisions that actually rewards you for catching a missed opportunity late. If you purchased a $1.5 million property five years ago and have been using straight-line depreciation, the catch-up deduction can exceed $300,000 in a single year.

What About Short-Term Rental Properties?

Short-term rental (STR) properties like Airbnb and VRBO units are excellent candidates for cost segregation. STR operators who materially participate in the rental activity (defined as more than 100 hours per year and more than anyone else) can use depreciation deductions to offset non-passive income like W-2 wages and business profits. This is a massive advantage. A W-2 employee earning $300,000 who also operates a short-term rental with a cost segregation study can use the accelerated depreciation to offset that W-2 income dollar for dollar, potentially saving $100,000 or more in taxes.

Step-by-Step: How to Execute Cost Segregation on a Property Over $1 Million

1. Gather your documents. You need the purchase agreement, closing statement (HUD-1 or ALTA), appraisal (showing land vs building allocation), construction blueprints or renovation invoices, and prior-year tax returns showing current depreciation schedules.
2. Select a qualified cost segregation firm. Choose a firm that uses licensed engineers, conducts physical site inspections, and produces IRS-compliant reports following the Cost Segregation Audit Techniques Guide. Avoid desktop-only studies.
3. Schedule the engineering inspection. The engineer will walk the property, photograph all components, and document every reclassifiable asset. This takes 2 to 8 hours depending on property size.
4. Review the draft report. The firm delivers a report identifying each asset, its cost, its assigned MACRS class life, and the total reclassified amounts. Review this with your tax strategist to confirm accuracy.
5. File Form 3115 if needed. If the property was placed in service in a prior year, file Form 3115 to change your accounting method and claim the Section 481(a) catch-up adjustment. This is filed with your current-year return.
6. Set up dual depreciation schedules. Create one schedule for your federal return (with bonus depreciation on reclassified assets) and a separate schedule for your California return (straight-line only). Track the difference as a timing adjustment.
7. Coordinate with your exit strategy. Document your 1031 exchange timeline and ensure your depreciation recapture exposure is calculated before making any sale decisions.
8. Activate AB 150 PTE election. If your property is held in an LLC or S Corp, file the AB 150 PTE election with the FTB to bypass the $40,000 SALT cap and reduce your combined effective tax rate.

Frequently Asked Questions

Does Cost Segregation Trigger an IRS Audit?

No. The IRS has published a detailed Audit Techniques Guide for cost segregation, which means they expect taxpayers to use this strategy. A properly conducted engineering-based study with a physical inspection and detailed documentation actually reduces audit risk because it demonstrates a defensible methodology. The IRS is more likely to challenge a taxpayer who claims arbitrary depreciation deductions without a formal study.

Can I Use Cost Segregation on a Property I Bought Years Ago?

Yes. You file Form 3115 to change your depreciation method and claim a Section 481(a) catch-up adjustment in the current tax year. No amended returns are required. The entire cumulative benefit is taken in one year.

How Long Does a Cost Segregation Study Take?

Most studies take 4 to 8 weeks from engagement to final report delivery. The physical inspection takes one day. The engineering analysis and report preparation take 3 to 7 weeks. Filing the results with your tax return requires coordination with your CPA or tax strategist.

What Happens to My Deductions When I Sell the Property?

Accelerated depreciation reduces your tax basis, which increases your gain on sale. Personal property (5-year and 7-year assets) is subject to Section 1245 recapture at ordinary income rates. Real property improvements are subject to Section 1250 recapture at a maximum 25% rate. A 1031 exchange defers both the capital gain and the depreciation recapture. Without a 1031, you may owe recapture taxes, but the time value of the money you saved in earlier years typically exceeds the recapture cost.

Is There a Minimum Property Value for Cost Segregation?

There is no IRS minimum, but as a practical matter, properties under $500,000 may not generate enough reclassified depreciation to justify the study cost. Properties over $1 million almost always produce a positive return on investment from the study. The sweet spot for maximum ROI is $1 million to $5 million, where study costs are relatively low compared to the tax savings generated.

Does California Allow Cost Segregation?

California allows cost segregation reclassification, meaning you can assign building components to shorter MACRS class lives on your California return. However, California does not allow bonus depreciation. You must depreciate the reclassified assets using straight-line depreciation over their assigned class lives (5, 7, or 15 years) on your California return. The benefit is smaller than the federal benefit but still significant because shorter class lives mean faster deductions even without bonus depreciation.

This information is current as of April 20, 2026. Tax laws change frequently. Verify updates with the IRS or FTB if reading this later.

Book Your Cost Segregation Consultation

If you own property worth $1 million or more and you have never ordered a cost segregation study, you are almost certainly overpaying your taxes by $40,000 to $200,000 or more. Every year you wait is another year of straight-line depreciation that could have been accelerated into first-year deductions. Our team will evaluate your property, estimate the reclassification potential, calculate the federal and California tax impact, and coordinate the study with your overall investment strategy. Click here to book your cost segregation consultation now.