Back to Blog

Case Study: Residential Cost Segregation in Practice

Sep 2024 1 min read

Last reviewed: 2026-02-26

Quick Summary

Case study walkthrough showing how reclassification can increase early-year depreciation compared with straight-line treatment.

Tax law changes over time. RentalWriteOff provides bonus depreciation applicability analysis in every report.

This walkthrough shows how cost segregation affects first-year depreciation for a typical single-family rental acquired after January 19, 2025, using real numbers.


The property

  • Property type: Single-family rental
  • Purchase price: $400,000
  • Land value: $80,000 (20% of purchase price)
  • Building basis: $320,000
  • Acquired and placed in service: 2025 (after January 19, 2025)

Without a study: standard 27.5-year treatment

Under standard MACRS treatment, the full $320,000 building basis is depreciated over 27.5 years.

  • Year 1 depreciation: $320,000 ÷ 27.5 = ~$11,636
  • Same amount every year for 27.5 years

With a cost segregation study

A study reclassifies eligible components into shorter recovery periods. For a typical single-family rental, a meaningful portion of building basis often qualifies:

Asset class Examples Basis reclassified
5-year property Appliances, carpet, window treatments, fixtures $32,000
15-year property Driveway, landscaping, fencing, exterior lighting $16,000
27.5-year (remaining) Structural building components $272,000
Total building basis $320,000

Year 1 depreciation with 100% bonus (OBBBA, acquired after Jan 19, 2025)

The One Big Beautiful Bill Act (signed July 4, 2025) permanently restored 100% bonus depreciation for property acquired after January 19, 2025. Short-life components qualify for full first-year expensing.

Component Basis Year 1 treatment Year 1 deduction
5-year property $32,000 100% bonus $32,000
15-year property $16,000 100% bonus $16,000
27.5-year property $272,000 Standard MACRS $9,891
Total Year 1 $57,891

Year 1 comparison

  • Standard treatment: $11,636
  • With cost segregation + 100% bonus: $57,891
  • Additional Year 1 deduction: ~$46,255

At a 32% marginal rate, that acceleration could represent roughly $14,800 in additional first-year tax savings. At 24%, approximately $11,100.

Important context

  • This is acceleration, not elimination. Larger early deductions reduce what's available in later years. The total depreciation over the life of the asset is unchanged.
  • Depreciation recapture applies at disposition. Your CPA should model the full lifecycle, not just Year 1.
  • Actual reclassification percentages vary by property. Furnished rentals, renovated properties, and properties with more site improvements typically show higher short-life percentages.
  • Bonus depreciation elections and state conformity are the CPA's call.

The ROI on the study itself

In this example, the additional Year 1 tax savings at a 32% rate (~$14,800) substantially exceeds the flat study fee — often by a wide margin for properties with meaningful basis.

Your CPA can run a quick projection before ordering to confirm the math works for your specific situation.


How the process works

  1. Submit core property details: address, purchase price, placed-in-service date, land value estimate
  2. Provide supporting documents if available (appraisal, settlement statement, photos)
  3. Receive a complete report with component-level classifications, allocated basis, and bonus depreciation applicability analysis

Reports typically delivered in 2 business days with a final quality check included.

For CPA firms, see our white-label platform. To order a study, get started here.