Awarded vendors
- AAR Testing and Inspection
- AKS Engineering & Forestry, LLC.
- Anchor QEA, Inc.
- BERK Consulting, Inc.
- CIC Valuation Group, Inc.
- Commonstreet Consulting
- Confluence Environmental Company
- Contract Land Staff LLC
- David Evans and Associates, Inc.
- DOWL
- Environmental Science Associates
- Equinox Research and Consulting International Inc.
- ESA
- Facet
- Fehr & Peers
- GA Creative
- GeoEngineers, Inc.
- GHD Inc.
- Haley & Aldrich, Inc.
- Harris Group Inc.
- HDR
- Herrera Environmental Consultants, Inc.
- HNTB Corporation
- Hough Beck & Baird Inc.
- Integra Realty Resources - Seattle
- Jacobs Engineering Group Inc.
- KBA, Inc. - Bellevue
- Kimley‑Horn
- KPFF Consulting Engineers
- Maul Foster & Alongi, Inc.
- Osborn Consulting Inc
- Otak, Inc.
- PACE Engineers, Inc.
- Parametrix, Inc
- Perteet Inc.
- PRR
- RHC Engineering
- SCS Engineers
- Shannon & Wilson
- Shea, Carr, Jewell, Inc. (dba SCJ Alliance)
- Terracon
- Tetra Tech
- Toole Design Group
- Transpo Group
- West Coast Code Consultants
- WSP USA