A Rapid Report normally takes 5 business days after all requested information is received. A fully engineered study normally takes 15 to 20 business days after all requested information and documentation is received. The fully engineered process includes a document request, a virtual or in-person property inspection, and report handoff. Rapid Report instead uses a self-directed questionnaire and engineer review, without a site visit.

This page covers the process itself, step by step. For what a cost segregation study is, how the deductions work, and whether it makes sense for your property at all, see our complete cost segregation study guide.

Before You Start: Does Your Property Qualify?

Nearly every income-producing property qualifies — commercial buildings, multifamily, single-family rentals, short-term rentals, and specialty facilities like hotels, restaurants, and self-storage. Both 39-year commercial and 27.5-year residential rental property benefit, and properties acquired years ago still qualify through a look-back study filed on Form 3115.

The minimum recommended property value is $200,000. Below that, study fees start to erode the net benefit. Our small property guide covers when lower-value properties still make sense.

Cost segregation is not right for every situation. Skip it, or wait, if you plan to sell within a year, have no current taxable income to offset, or cannot use the deductions because of passive activity loss limits. The study guide works through that analysis in full.

The Five Steps

• Gather your documents (before engagement)
• Select a provider (before engagement)
• Site inspection
• Engineering analysis and asset classification
• Report delivery and CPA coordination

The five steps below describe a fully engineered study. Its 15-to-20-business-day delivery timeline starts after all requested information and documentation is received, not simply at engagement. Rapid Report follows a separate questionnaire-based workflow.

Step 1: Gather Your Documents

Your cost segregation engineer needs:

• Purchase agreement and closing statement
• Construction blueprints and architectural plans
• Contractor invoices and payment applications
• Change orders and construction draw schedules
• Property appraisal reports

Create digital copies of everything. Missing documentation can delay your study and weaken component identification. For existing buildings without original construction documents, your engineer relies more heavily on the site inspection. Requirements vary depending on whether you purchased, built, or renovated, so check which documents you need for a cost segregation study before you start gathering.

Step 2: Select a Provider

Choose firms with relevant engineering, construction-cost, and tax knowledge. R.E. Cost Seg's Rapid Report and fully engineered services both include engineer review.

Essential qualifications:

• Relevant engineering, construction-cost, and tax-classification expertise
• Proven experience with 100% bonus depreciation strategies
• Detailed, audit-ready reports
• Fixed-fee pricing (avoid contingency arrangements)
• References from similar property types

Interview multiple firms. Ask for sample reports. Verify their methodologies align with the IRS Audit Techniques Guide standards.

Can I perform a cost segregation study myself?

Owners can gather records and supply property information. The classification and cost-allocation analysis still needs appropriate expertise and substantiation. A self-directed questionnaire with engineer review is not the same as an unsupported DIY allocation. Ask the provider what methodology, review, and documentation the service includes.

Step 3: The Site Inspection

A fully engineered study includes a property inspection, either virtually or in person. Confirm the appointment and scope with the provider. Rapid Report does not include a site visit. Inspection documentation may cover:

• Electrical and plumbing systems
• HVAC equipment and ductwork
• Flooring materials by area
• Interior and exterior finishes
• Site improvements and landscaping

Accompany your engineer during the inspection where you can. Your knowledge of recent improvements or specialized systems helps identify additional components.

Step 4: Asset Classification

Engineers assign components to supported recovery periods. The examples below are not automatic classifications: function, installation, the taxpayer's activity, and the applicable asset class matter. IRS Publication 946 identifies residential rental appliances, carpets, and furniture as five-year property.

5-Year Property:

• Decorative lighting
• Carpeting and qualifying removable floor coverings, subject to the actual use and installation
• Movable partitions
• Dedicated electrical for equipment

7-Year Property:

• Office furniture and fixtures when the applicable asset class prescribes seven years. Residential rental furniture is generally five-year property, not seven-year property.

15-Year Property:

• Parking lots and sidewalks
• Landscaping
• Qualifying site improvements; utilities serving a building can instead follow the building's recovery period
• Exterior lighting

Qualifying shorter-lived assets may be eligible for bonus depreciation, but the recovery period alone does not establish the 100% rate. Acquisition timing, placed-in-service dates, required ADS treatment, elections, and other exclusions matter. Residential rental furnishings generally belong in the five-year rather than seven-year category.

How Much Gets Reclassified

How much moves out of the long-life schedule depends on the asset class. R.E. Cost Seg models each class against a baseline and an optimal result, measured as a share of depreciable basis — the purchase price less land value, not the purchase price itself.

Specialty assets with heavy site work — car washes, gas stations, RV parks — run considerably higher, because most of the value sits in land improvements rather than the building. Where a specific property lands inside its range depends on site development, finish level, and how much documentation supports the component detail.

Step 5: Report Delivery and CPA Coordination

Your final report includes:

• Executive summary with total reclassified amounts
• Detailed asset listings with bonus depreciation calculations
• Supporting photographs and documentation
• Depreciation schedules for tax filing
• Engineering methodology explanations

Review every classification with your CPA and make sure your tax preparer understands how to implement the results. The report becomes permanent substantiation in your tax record. Our guide to reading a cost segregation report walks through what each section means.

What It Costs and What It Returns

A Rapid Report starts at $950. A fully engineered study starts at $2,320 for residential property and $2,730 for commercial. Obtain a property-specific quote and scope. For the service discussion, see our guide to cost segregation study pricing.

Compare the study fee with modeled tax benefits using your property's basis, supported classifications, bonus eligibility, tax rates, and usable deductions. A fee multiple is a scenario result, not a guaranteed or universal return.

A Worked Example

Take a $1,000,000 single-family rental with 20% of the purchase price allocated to land:

• Purchase price: $1,000,000
• Land value: $200,000
• Depreciable basis: $800,000

At the optimal result for a single-family home (38% of depreciable basis):

• 5-year property (23%): $184,000
• 15-year property (15%): $120,000
• Total reclassified: $304,000
• 27.5-year property: $496,000

Assume the $304,000 comprises qualifying assets acquired and placed in service after January 19, 2025, with 100% business use, no required ADS treatment, no election out, and fully usable deductions. IRS Notice 2026-11 supplies the timing and bonus rules. The bonus deduction would be $304,000. At an assumed 37% federal marginal rate, that portion produces $112,480 of federal tax reduction, excluding state taxes. This does not subtract the regular depreciation otherwise available, so it is not an incremental-with-versus-without-study calculation.

This is a property-specific example at the optimal end of the range, not a typical or guaranteed outcome. A baseline result on the same property (27%) would reclassify $216,000 instead.

One thing to be clear about: this is acceleration, not forgiveness. You claim the same total depreciation over the life of the building either way. The benefit is the time value of money and the ability to match deductions against a high-income year. Accelerated depreciation also increases recapture exposure on sale, which belongs in the analysis.

Can You Actually Use the Deduction?

A study supports asset classification and depreciation calculations. Your preparer must apply eligibility rules, elections, and the ordered loss limitations before determining the currently usable deduction.

Rental real estate losses are generally passive. Real Estate Professional Status requires both statutory service tests and does not, by itself, make rental losses nonpassive. Material participation in the relevant rental activity is also required. An STR meeting a rental-activity exception still needs material participation for nonpassive treatment. IRS Publication 925 also explains the limited rental real estate allowance and the basis, at-risk, passive, and excess-business-loss rules.

If passive-loss limits disallow a loss, it generally carries forward. It may offset future passive income or be released on a qualifying fully taxable disposition of the entire activity to an unrelated person. Other deduction limits and grouping can affect the result. Review the current benefit and future recapture with your tax advisor before ordering a study.

Common First-Timer Mistakes

• Ordering the study before checking the passive activity position. The deduction may not be usable this year.
• Quoting reclassification against purchase price. It is measured against depreciable basis, after land is carved out.
• Assuming every interior renovation is QIP. Qualified improvement property covers eligible Section 1250 interior improvements you make to nonresidential buildings and place in service after the building was first placed in service. Residential rental improvements are not QIP. Building enlargements, elevators and escalators, and the internal structural framework are excluded. Separately classified personal property and land improvements require their own analysis.
• Poor documentation. Keep closing statements, invoices, and the report itself for audit defense.
• Choosing an unqualified provider. Engineering methodology is what the IRS Audit Techniques Guide asks for.
• Forgetting state conformity. Not every state follows federal bonus depreciation. Ask your CPA about your state before forecasting the benefit.

Getting Started Checklist

□ Confirm with your CPA that you can use the deductions this year
□ Estimate your savings using R.E. Cost Seg's depreciation calculator
□ Gather closing statement, blueprints, and contractor invoices
□ Request sample reports from two qualified firms
□ Confirm engineering methodology and fixed-fee pricing
□ Coordinate timing with your CPA ahead of your filing deadline

Ready to start? Request a free proposal and our team will review your property details and return a savings estimate at no cost.