Best Cost Segregation Companies for Multifamily Properties (2026)

Last updated March 2026 · Apartments, duplexes, 5+ units

Multifamily is where cost segregation studies get serious. A single-family rental might reclassify 20-25% of the building into accelerated buckets. A well-done multifamily study can hit 25-35% or higher, because the property type is loaded with components that the IRS allows you to depreciate faster: shared HVAC systems, common area finishes, parking lots, landscaping, fencing, laundry equipment, fitness center buildouts, and per-unit personal property that multiplies with every door.

The challenge is that pricing scales up fast, too. Some national firms charge commercial rates for anything over two units. I have seen quotes of $8,000 for a 12-unit garden apartment -- a property where the engineering is not meaningfully more complex than a single-family home with the same square footage. Meanwhile, a handful of providers offer flat-rate or value pricing for small multifamily (2-4 units) that makes the math work even on a $300,000 duplex.

There is also a critical tax distinction that affects which provider you choose. Properties with 1-4 residential units depreciate on a 27.5-year schedule. Properties with 5 or more units are classified as commercial and depreciate over 39 years. That longer baseline makes cost segregation proportionally more valuable for larger apartment buildings -- and it means the study methodology needs to account for commercial-grade shared systems that do not exist in smaller properties.

Top 10 Cost Segregation Companies for Multifamily (2026)

#1. KBKG — Best for Large Multifamily (50+ Units)

★★★★☆ 8.5 / 10  ·  $5K – $15K+  ·  4 – 8 weeks

KBKG is the default choice for large apartment complexes and institutional multifamily. They have full engineering teams, deep experience with 100+ unit properties, and the kind of audit-defense track record that matters when the numbers get into seven figures of reclassified depreciation. Their studies handle shared mechanical systems, common area allocations, and site improvement breakdowns at a level of detail that smaller firms simply cannot match.

The trade-off is cost and speed. KBKG charges commercial rates regardless of property size -- expect $5,000 minimum even for a duplex, which makes no economic sense on a small multifamily property. Their turnaround is also measured in months, not days. If you own a 200-unit apartment complex worth $30 million, KBKG is an excellent choice. If you own a fourplex, you are overpaying for capability you do not need.

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#2. R.E. Cost Seg — Best for Small Multifamily (2-10 Units)

★★★★☆ 8.0 / 10  ·  $895 – $5K+  ·  5 – 10 days / 3 – 4 wks

R.E. Cost Seg hits a good middle ground for small-to-mid multifamily. Their Rapid product at $895 works well for duplexes and triplexes where the component profile is not dramatically different from a single-family home. For larger properties, they scale into more detailed engineering studies with site visits where warranted.

The limitation is at the top end. For 50+ unit complexes with complex shared systems and significant common areas, their methodology gets thinner. I would cap their sweet spot at around 20-30 units. Below that, the pricing is competitive and the turnaround is solid. Above that, you probably want KBKG or another national firm with dedicated multifamily engineering capacity.

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#3. Cost Seg Smart — Best Value for 2-4 Unit Properties

★★★★☆ 8.0 / 10  ·  From $795  ·  Under 1 hour

Disclosure: this is our company. Cost Seg Smart is an automated platform that delivers engineering-based cost segregation reports in under an hour. Multifamily pricing starts at $995 for 2-4 unit properties (duplexes through fourplexes), which is a fraction of what traditional firms charge for the same property type. The engine handles per-unit component allocation, shared system classification, and site improvement breakdowns automatically using RSMeans cost data and IRS MACRS rules.

The honest limitation: Cost Seg Smart works best for standard residential multifamily. If you own a 100-unit apartment complex with a clubhouse, pool, fitness center, and mixed-use retail on the ground floor, you need a firm that can do a physical walkthrough of those specialized spaces. For a duplex, triplex, or fourplex -- which is the majority of multifamily investors -- the automated approach delivers the same classifications at 10-20% of the price.

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What to Look for in a Multifamily Cost Segregation Provider

Not every cost segregation firm handles multifamily well. Here are the four things I look for when evaluating providers for apartment buildings and multi-unit properties:

Shared systems handling. Multifamily properties have HVAC, plumbing, and electrical systems that serve multiple units. A good study breaks these into their component parts -- the distribution piping is structural (39-year or 27.5-year), but individual unit connections, thermostats, and fixtures are often 5-year or 15-year property. Firms that treat the entire HVAC system as one line item are leaving money on the table.

Site improvement allocation. Parking lots, sidewalks, landscaping, fencing, exterior lighting, and drainage systems are 15-year property. On a large apartment complex, site improvements can represent 10-15% of the total building cost. I have seen studies that lump these into the building shell -- that is a missed reclassification that costs the owner real money every year.

Unit count scaling. Does the provider price fairly as unit count increases? Some firms charge $5,000 for a duplex and $6,000 for a 20-unit building, which makes no sense -- the 20-unit property has 10x the components. Others scale linearly, charging per unit, which quickly becomes absurd for large complexes. The best providers have tiered pricing that reflects the actual increase in analytical complexity.

Common area FF&E. Lobbies, hallways, leasing offices, fitness centers, laundry rooms, and amenity spaces are rich with 5-year and 7-year personal property: carpeting, cabinetry, appliances, decorative lighting, security systems, and furniture. A thorough study itemizes common area components separately from unit-level components. If your study report does not mention common areas, something was missed.

Multifamily Cost Segregation FAQ