A cost segregation study takes 5 to 10 business days for a Rapid Report, or 15 to 20 business days for a fully engineered study, and involves three touchpoints for you: a document request, a site visit, and the report handoff. Everything else happens on the provider's side.

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

Turnaround from engagement is 5 to 10 business days for a Rapid Report and 15 to 20 business days for a fully engineered study. Gathering documents and choosing a provider happens before that clock starts.

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 engineering expertise and tax knowledge. R.E. Cost Seg employs both engineers and tax professionals to ensure IRS compliance.

Essential qualifications:

• Licensed engineers on staff
• 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?

No — not if you want a defensible cost segregation study. A study requires supported asset classification, construction-cost analysis, tax knowledge, and documentation that can withstand review. Property owners can help gather records, but the analysis should be completed by qualified cost segregation specialists. Professional fees typically represent a low single-digit percentage of total tax savings.

Step 3: The Site Inspection

Your engineer will schedule a site visit lasting 2 to 8 hours, depending on property complexity, conducted either on-site or virtually. They photograph and document every component, measuring and cataloging:

• 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 segregate components into their correct recovery periods.

5-Year Property:

• Decorative lighting
• Carpeting and vinyl flooring
• Movable partitions
• Dedicated electrical for equipment

7-Year Property:

• Furniture and fixtures
• Equipment-specific HVAC
• Point-of-sale systems

15-Year Property:

• Parking lots and sidewalks
• Landscaping
• Site utilities
• Exterior lighting

All three categories are eligible for 100% bonus depreciation. Each classification requires engineering justification and IRS code references. Residential properties typically carry little or no 7-year property; most of the reclassification lands in the 5- and 15-year buckets.

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. Industry-wide, engineering-based studies typically run $3,000–$15,000+.

Qualified properties commonly generate potential first-year tax savings of 10–25× or more than the study fee. Actual results depend on the property's depreciable basis, land allocation, reclassification results, applicable tax rates, bonus-depreciation eligibility, the study fee, and your ability to use the deductions.

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

With 100% bonus depreciation permanent for property acquired and placed in service after January 19, 2025, the full $304,000 is deductible in year one. At a 37% marginal rate that is roughly $112,000 in first-year tax reduction, against about $2,320 for a fully engineered residential study.

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 produces the deduction. The passive activity rules determine where you can apply it.

Rental losses are passive by default and offset only passive income. Two routes change that: Real Estate Professional Status, which requires more than 750 hours annually in real property trades or businesses and more than half your total working time, or the short-term rental exception, which applies when average guest stays are seven days or fewer and you materially participate.

If neither applies, the accelerated loss is still generated and still valuable. It suspends and carries forward, offsetting future passive income or releasing on disposition. Ask your CPA which route is available to you before you order the study, not after.

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.
• Ignoring qualified improvement property. Interior improvements to existing buildings qualify as 15-year property.
• 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.