| 3c Controls | B + C7, C10, D62 | 2009 | Active |
| Abbott I Reed Inc | B | 2008 | Active |
| Advanced Septic Solutions | A, B | 2021 | Active |
| Aero Consulting Group | B | 2026 | Active |
| Alonzo Mark Construction LLC | A, B | 1995 | Active |
| American Cornerstone Engineering Group Inc | A | 2025 | Active |
| Anthony W Viola General Contractor Inc | B | 2020 | Active |
| Artifex Industries Inc | B | 2012 | Active |
| B & T Construction Inc | A, B | 2024 | Active |
| Bahr Builders Inc | B | 2013 | Active |
| Benson Development Inc | B | 2001 | Active |
| Big Coast Skylight Construction Inc | B | 2025 | Active |
| Borland Built And Managed LLC | B | 2021 | Active |
| Braunschweig Construction | B | 2008 | Active |
| Breska & Associates Co | B | 2001 | Active |
| Bunnell Construction Inc | B | 1979 | Active |
| C P Enterprises Inc | B | 1994 | Renew by Nov 30, 2026 |
| Cairn Collaborative Inc | B | 2018 | Active |
| Campfire Construction | B | 2018 | Active |
| Castlerock Development | A, B + ASB, C10 | 1996 | Renew by Dec 31, 2026 |
| Coast Construction Inc | B | 2001 | Active |
| Coastal Construction & Engineering Inc | A, B | 2003 | Active |
| Coastal Venture Builders LLC | B | 2026 | Active |
| Community Action Partnership Of San Luis Obispo County Inc | B | 1991 | Active |
| Construction Company Of San Luis Obispo Inc The | B | 2018 | Active |
| Covelop Inc | B | 2014 | Active |
| Craghead D A Construction Inc | A, B + C8 | 1988 | Active |
| D C Design & Construction | A, B + HAZ | 2006 | Active |
| David Construction & Management Inc | B | 2018 | Active |
| Del Pesco Inc | B | 2000 | Active |
| Diablo Valley Builders Inc | B | 1999 | Active |
| Drake Excavating & Aggregates Inc | A + C12 | 2016 | Renew by Dec 31, 2026 |
| Executive Construction Group | B | 2016 | Active |
| Familiar Forms Inc | B | 2014 | Active |
| Form Design + Build Inc | B | 2009 | Renew by Dec 31, 2026 |
| Fortini Landscapes Design Build | B + C27 | 2020 | Active |
| Frantz Construction Inc | B | 2018 | Active |
| G C N Construction Inc | B + C36 | 1999 | Active |
| Goodwin Construction Group Inc | A, B | 1983 | Active |
| Green Goods | B | 2009 | Active |
| H J Construction Inc | A, B | 2005 | Active |
| Handley Jack Construction Services | B | 2012 | Active |
| Hanna Construction Engineering Inc | A, B + C8 | 1978 | Active |
| Hayward Construction | A | 2005 | Active |
| HD General Engineering Inc | A | 2025 | Active |
| Holland & Knapp Construction Inc | B | 2004 | Active |
| Hunter J A Construction Inc | B + C5, C6 | 1992 | Active |
| J G Construction A Partnership | B | 1997 | Active |
| J T Construction | B | 2008 | Active |
| J W Design & Construction Inc | B | 1989 | Active |
| Jebl Engineering & Construction Inc | A, B + C10, C46 | 2008 | Active |
| K C I Environmental Inc | A + C27 | 2002 | Active |
| K R Construction Inc | B + C36 | 1994 | Active |
| Kairos Manufacturing Inc | B + C17 | 2017 | Active |
| Kimbell & Brown Construction Inc | B + C53 | 2009 | Active |
| Knecht's Plumbing & Heating Inc | B + C4, C10, C16 +3 | 1979 | Active |
| Knight And Sons Inc | A, B | 2002 | Active |
| Kyle Company Roofing | B + C2, C20, C39 +1 | 1985 | Active |
| Landwell Landscape Construction | B + C27 | 2016 | Active |
| LBM Property Solutions Inc | B | 2017 | Active |
| Los Brothers Innovations General Contractors | B | 2026 | Active |
| Madonna John Construction Company Inc | A, B + C12, HAZ | 1978 | Active |
| Maino Construction Company Incorporated | A, B + ASB, D52 | 1982 | Active |
| Mak Family Construction | A, B | 2023 | Active |
| Marwal Construction Inc | B | 1993 | Active |
| McKinley R Construction Incorporated | B | 2017 | Active |
| Mfi Limited | B | 2001 | Active |
| Monarch Window Inc | B + C17 | 2014 | Active |
| Moore Greg Construction Inc | B + C13 | 1992 | Active |
| Mountain Pacific Builders Inc | B | 2004 | Active |
| N K Builders Incorporated | B | 1999 | Active |
| Newton Construction & Management Inc | A, B + C10, C16 | 2000 | Active |
| Nviro | A, B + C10, C36, C51 | 2019 | Active |
| P W S | B | 2010 | Active |
| P W S Construction Inc | B | 2004 | Renew by Dec 31, 2026 |
| Pac - West General Inc | A, B + C10 | 2009 | Active |
| Pacific Builders Of Slo Inc | A, B | 2005 | Active |
| Pacific General Contracting Inc | B | 2003 | Active |
| Peoples' Self-Help Housing Corporation | B | 1986 | Active |
| Phillips Flooring America | B + C15, C54 | 1990 | Active |
| Pittman Construction Inc | B | 1992 | Active |
| Precision Construction Services | B | 2017 | Active |
| Price Construction | B | 1987 | Active |
| Quaglino Roofing | B + ASB, C22, C39 | 1968 | Active |
| R Burke Corporation | A, B | 1970 | Active |
| Rarig Construction Inc | A, B + C39, C51 | 1980 | Active |
| Reasons Slo Fence | B + C13 | 1983 | Active |
| Ritchie Built LLC | B | 2026 | Active |
| Rogers & Pedersen Construction Inc | B | 2013 | Active |
| Rspaul Company Inc | B | 2007 | Active |
| Rush Creek Construction | B | 1984 | Renew by Dec 31, 2026 |
| Rutledge Inc | B | 1994 | Active |
| S K S Real Estate And Development Inc | B | 2016 | Active |
| Sabol Construction Inc | B | 2020 | Renew by Nov 30, 2026 |
| Scarry David Construction Inc | A, B | 1998 | Renew by Dec 31, 2026 |
| Schaefer Custom Homes | B | 1992 | Active |
| Seamair General Engineering | A, B + D12, HAZ | 2016 | Active |
| Selna Construction Inc | B + C27, C29 | 1997 | Active |
| Servpro Of San Luis Obispo & Atascadero | B | 1998 | Active |
| Shetler Construction Inc | A, B + ASB, C10 | 1992 | Renew by Nov 30, 2026 |