| Horizon Construction Unlimited Inc | B | 2010 | Active |
| HPS Plumbing Services | A, B + C2, C4, C10 +7 | 2001 | Active |
| Hudson Construction | B | 2017 | Active |
| Huffco Incorporated | A, B + C8, C27 | 2020 | Active |
| Hwe Mechanical | A | 1999 | Active |
| I C E Inc | A + HAZ | 2015 | Active |
| I Q General Construction Inc | B + C8, C35, C39 | 1991 | Active |
| Icd-Sca Joint Venture | B | 2026 | Active |
| Imperial Energy Electric Inc | B + C10 | 2023 | Active |
| Industrial Controls Group Inc | B + C10 | 1990 | Active |
| Industrial Design & Construction Inc | A, B + C21, C60 | 2001 | Active |
| Industrial Systems Consulting Inc | A | 2026 | Active |
| Integral Solutions General Contractor Corp | B | 2026 | Active |
| Integrated Home Solutions Group Inc | A + C7 | 2018 | Renew by Dec 31, 2026 |
| Intrepid Plastering LLC | B + C35 | 2022 | Active |
| Ironworks | B + C23, C33, D28 | 2016 | Renew by Nov 30, 2026 |
| J & A House Builders Inc | B | 2020 | Active |
| J & M Land Restoration Inc | A + D59 | 1987 | Active |
| J A Praut Plumbing Inc | B + C36 | 2025 | Active |
| J B Y Construction Inc | B | 2023 | Active |
| J C & Z Company Inc | B | 2017 | Active |
| J E Electric & Construction Services Inc | B + C10 | 2018 | Active |
| J G Construction & Custom Homes Inc | B | 2008 | Active |
| J T J Construction Inc | B + C8 | 2002 | Active |
| J T S Construction | A, B + C8, C10 | 1995 | Active |
| J T S Modular Inc | B | 2001 | Active |
| Jaco Oil Company | A + D40, HAZ | 2012 | Active |
| Jaspar Dee And Associates | A, B | 1982 | Active |
| Jaydee Contractors Inc | A, B + C8 | 2025 | Active |
| JDCB Inc | B | 2006 | Active |
| Jeremy Willer Construction Inc | B | 2012 | Active |
| Jireh Building Inc | B | 2018 | Active |
| JLH Construction | B + ASB | 2018 | Active |
| JM Pipeline Construction Inc | A | 2017 | Active |
| JMGG Services LLC | B | 2026 | Active |
| Jmilam Construction Services Inc | B | 2025 | Active |
| John Construction | B | 2018 | Active |
| Johnston Ed Construction Inc | B + C29 | 2004 | Active |
| Joint Construction Inc | A | 2022 | Active |
| Jon Rowles Construction Inc | B | 2022 | Active |
| Jones L Incorporated | A, B + C12 | 2022 | Active |
| Josco Construction Inc | B | 1991 | Active |
| JP Hess Inc | B | 2025 | Active |
| Jsa Building Construction Inc | B | 2026 | Active |
| Justin Homes Co Inc | B | 2023 | Active |
| JWD Construction Inc | B | 2019 | Active |
| K Corp Enterprises Inc | A, B + C53 | 2011 | Renew by Dec 31, 2026 |
| Kal West Contractors Inc | A, B + C33, HAZ | 2023 | Active |
| Ken W Smith Construction Inc | B + C8 | 2018 | Renew by Dec 31, 2026 |
| Kern Asphalt Paving & Sealing Co Inc | A + C8, C12, C21 +1 | 2002 | Active |
| Kern Canyon Builders LLC | B | 2026 | Active |
| Kern County Construction Inc | A, B + C10, HAZ | 1985 | Active |
| Kern County Partitions & Specialty's | B | 2025 | Active |
| Kern General Construction | B | 2015 | Active |
| Kern Pacific Construction Company | A + C34 | 1998 | Active |
| Kern River Contractors Inc | B | 2024 | Active |
| Kern Steel Fabrication Inc | A + C33, C51 | 1980 | Active |
| Kern Valley Builders Inc | B | 2019 | Active |
| Klassen And Smith Construction Inc | B | 2016 | Active |
| Klassen Corporation | B + C8, C51 | 1978 | Active |
| Klassen Management Inc | B | 2019 | Active |
| Knox C L Inc | A + HAZ | 1999 | Active |
| Krcorp Resources Inc | A | 2005 | Active |
| KS Custom Homes | B | 2025 | Active |
| KS Industries LP | A + C10 | 2025 | Active |
| Ksi Engineering Inc | A | 1991 | Active |
| Kustom Kutz Construction Inc | B + C5 | 2011 | Active |
| Landstone Construction LLC | B | 2025 | Active |
| Laurel Ag & Water LLC | A + C10, D21 | 2019 | Active |
| Left Electric LLC | B + C10 | 2024 | Active |
| Legacy Homes | B + C53 | 2001 | Active |
| Lentz Construction | A + C8 | 2004 | Active |
| Lion Builders Inc | A, B + C5 | 2014 | Active |
| Litten's Backhoe Service Inc | A | 1998 | Active |
| Littles Finish Trim & Hardware Inc | B | 2006 | Active |
| LKG Engineering Construction Inc | A + D38, D63 | 2018 | Active |
| Locator Real Estate Co | B | 2009 | Active |
| Loop Electric Inc | A + C10, C31 | 1986 | Active |
| Lopez-Canchola Remodeling | B2 | 2026 | Active |
| Lowken Renovations LLC | B | 2010 | Active |
| LT Platinum Plumbing And Mechanical Inc | B + C36 | 2025 | Active |
| Lucca Building Company The | B | 2015 | Active |
| Lucy's Building Solutions | B | 2023 | Active |
| Luna General Builders Inc | B | 2018 | Active |
| Luther Lewis Construction Inc | B | 1995 | Active |
| Luxe General Contractor Inc | B | 2022 | Active |
| M B Construction Inc | B | 2022 | Active |
| M Bros Construction Inc | B | 2022 | Renew by Dec 31, 2026 |
| M Construction Co Inc | A + C12, C21 | 1981 | Active |
| M P Environmental Services Inc | A + C12, C21, HAZ | 1991 | Active |
| M Reyneveld Construction Inc | B | 2025 | Active |
| M3 Remodeling Inc | B | 2017 | Active |
| Maca Development | B | 2022 | Active |
| Machado Matt Construction Inc | B + HAZ | 2016 | Active |
| Madison Homes | B | 2003 | Active |
| Mahan / Briscoe Construction | B | 2000 | Active |
| Mariott Welding Inc | A + C60, HAZ | 2002 | Active |
| Martinez Electric Inc | B + C10 | 2003 | Active |
| Mashburn Waste & Environmental Services | A + HAZ | 2023 | Active |
| Maverick Construction Inc | B | 2024 | Active |