Best cost segregation companies serving Seattle, WA (2026)

A comparison of 6 providers, what each does best, at what price, with what turnaround.

Disclosure (FTC §255): This page is published by Cost Seg Smart, one of the providers compared below. We've tried to compare honestly, the 'best for' framing reflects each provider's actual sweet spot, not paid placement. See methodology below.

Best for...

Different providers fit different buyer profiles. Here's the short version:

Detailed comparison

Provider Price range Turnaround Site visit Audit support
Cost Seg Smart (this site's operator) $495–$2,995 Under 1 hour Remote (photos + assessor data + plan documents) Written audit defense included with every study
KBKG $3,000–$25,000+ 4–8 weeks On-site required for most engagements Add-on retainer
CSSI (Cost Segregation Services, Inc.) $5,000–$30,000 6–10 weeks On-site Included; expert testimony available
Engineered Tax Services (ETS) $5,000–$50,000 6–12 weeks On-site Included
Capstan Tax $4,000–$20,000 4–8 weeks On-site Included
Local CPA + engineering review Varies, typically $2,500–$10,000 Varies Depends Depends, verify in engagement letter

Seattle-specific note

Seattle tech-W-2 professional buyers benefit from a provider whose workflow explicitly addresses the §469 passive-loss problem and documents which workarounds are realistic. Cost Seg Smart's study output includes notes on STR-loophole feasibility, ADU LTR treatment, and real-estate-professional status considerations for the buyer's specific property profile.

How to choose

Three questions to answer before contacting any provider:

  1. Property size and complexity. Under $5M residential or small commercial? The remote-first/automated providers (Cost Seg Smart) give you the same MACRS reclassification at substantially lower cost. Above $5M, especially with mixed-use or industrial assets? On-site engineer-led firms (KBKG, CSSI, ETS, Capstan) are worth the extra cost because the FF&E density and complex-component identification matters more.
  2. How important is audit defense to you? All providers include some level of audit-package documentation. Cost Seg Smart includes written audit defense in every study at no extra charge, useful if you're cost-conscious and want certainty. Some traditional firms include expert testimony as an add-on retainer; ask explicitly.
  3. CPA relationship. If your CPA has a strong preference for an engineer-led firm because of established workflow, follow that, the savings difference is rarely worth the friction of disagreeing with your CPA on methodology. If your CPA is open or doesn't have a preference, the lower-cost remote-first option captures the same dollars.

Methodology of this comparison

Price ranges are based on publicly stated tiers and industry sources as of 2026. Turnaround times reflect typical engagement lengths and may vary. We do not receive compensation from any other provider listed; this is not affiliate content.

The "best for" framing reflects each provider's actual public sweet spot, not paid placement. We don't claim to be #1 for every customer profile. We're the best fit for the segment described in our row (fast, affordable, remote-first, residential + STR + small commercial under $5M). For larger commercial portfolios (office, retail, industrial, multifamily 5+), engineer-led firms with on-site capacity are the right choice, see commercialcostseg.com for our institutional commercial coverage and provider patterns.

Cross-firm review data and provider scorecards live at costsegregationreviews.com for buyers comparing across the industry. For deeper cross-provider pricing breakdowns by study type and basis range, costsegregationpricing.com tracks the wider pricing market.

See the Seattle engine benchmarks   Start a Cost Seg Smart study