| California Capital & Investment Group | Mark Andrew Mcclure | — | (925) 464 1788 | GC, remodel, ADU | Pleasant Hill · Contra Costa County | — | — |
| California Colors Painting Company INC | Steven William Dondanville | — | (925) 938 6288 | Windows, patio, painters | Pleasant Hill · Contra Costa County | — | — |
| California Comfort Air INC | Fernandez Gerardo | — | (925) 250 7055 | HVAC | Oakley · Contra Costa County | — | — |
| California Concrete Contractors LLC | Aurelio Cardenasgonzalez | — | (925) 395 7277 | Other | Concord · Contra Costa County | — | — |
| California Concrete Overlay INC | Velasco Esaul Esquivel | — | (925) 381 1644 | Other | Martinez · Contra Costa County | — | — |
| California Construction Pro Service | Alexey Voronov | — | (818) 305 7205 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| California Contractors | Esmaili Masood | — | (510) 910 6868 | GC, remodel, ADU | Kensington · Contra Costa County | — | — |
| California Custom Contractors INC | Gregory John Meo | — | (925) 260 1512 | Other roofers | Lafayette · Contra Costa County | — | — |
| California Dirt Incorporated | Gerard Joseph Hynes | — | (510) 970 7995 | Other | Richmond · Contra Costa County | — | — |
| California Elite Homes | Majid Jafarbegloo | — | (925) 557 9242 | GC, remodel, ADU | Orinda · Contra Costa County | — | — |
| California Falls & Fountains | California Falls & Fountains | — | (925) 822 5013 | Windows, patio, painters | Concord · Contra Costa County | — | — |
| California Fire Detection | Sean Jeffrey Shafer | — | (929) 550 9203 | Electricians | Pleasant Hill · Contra Costa County | — | — |
| California Glazing Solutions | California Glazing Solutions | — | (646) 951 5519 | Windows, patio, painters | Alamo · Contra Costa County | — | — |
| California Heating And Cooling INC | Gabriel Raul Galvez | — | (925) 756 0700 | HVAC | Antioch · Contra Costa County | — | — |
| California Highway Construction Group INC | Jorge Edgard Quinones | — | (925) 766 7014 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| California Interior Shutters | California Interior Shutters | av8ermark@aol.com | (925) 867-3745 | Other | San Ramon · Contra Costa County | — | — |
| California Mechanical | California Mechanical | — | (925) 301 5920 | HVAC | Brentwood · Contra Costa County | — | — |
| California Organic Landscaping | California Organic Landscaping | — | (707) 599 7585 | Windows, patio, painters | Pacheco · Contra Costa County | — | — |
| California Outdoor INC | Shawn Daniel Czirban | — | (831) 915 4875 | Windows, patio, painters | Concord · Contra Costa County | — | — |
| California Pacific Painting | California Pacific Painting | — | (925) 708 7951 | Windows, patio, painters | Concord · Contra Costa County | — | — |
| California Pavers Interlocking Service | Magno Leonardo Gomez Rivas | californiapavers2025@gmail.com | (510) 672 7257 | Windows, patio, painters | Richmond · Contra Costa County | — | — |
| California Precision Building | California Precision Building | — | (925) 323 1591 | GC, remodel, ADU | Pleasant Hill · Contra Costa County | — | — |
| California Professional Builders INC | Mohamad Lamea Alatasi | — | (650) 996 6898 | GC, remodel, ADU | Danville · Contra Costa County | — | — |
| California Roof Pros | Anthony Todd Stotesberry | — | (415) 516 4657 | Other roofers | Concord · Contra Costa County | — | — |
| California Sewer Engineering INC | Jose De Jesus Gonzalez | — | (510) 480 2488 | Other | Hercules · Contra Costa County | — | — |
| California Spa Service | Paul Eugene Stierwalt | — | (925) 935 3558 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| California Sunrooms Co | Glenn Alfred Skidmore | — | (925) 939 6500 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| California Ust Services | John Patrick Courant | — | (925) 595 8230 | Other | San Ramon · Contra Costa County | — | — |
| California Window Masters Installation | California Window Masters Installation | — | (877) 464 4005 | Windows, patio, painters | San Ramon · Contra Costa County | — | — |
| Calikraft Landscape | Calikraft Landscape | — | (510) 681 4938 | Windows, patio, painters | Antioch · Contra Costa County | — | — |
| Calipro Remodeling INC | Alex Makeev | caliproremodeling@gmail.com | (925) 557 7732 | GC, remodel, ADU | Pleasant Hill · Contra Costa County | — | — |
| Calisco Roofing | Jose Alexis Pena | — | (925) 437 7623 | Other roofers | Brentwood · Contra Costa County | — | — |
| Callado Concrete INC | Jose Eduardo Sandoval | — | (209) 612 7007 | Other | Oakley · Contra Costa County | — | — |
| Calpro Remodeling INC | Altangerel Baldorj | — | (415) 405 5652 | GC, remodel, ADU | Pleasant Hill · Contra Costa County | — | — |
| Calpro Roofing | Hadley Eric Hoff | — | (925) 684 7501 | Other roofers | Brentwood · Contra Costa County | — | — |
| Calpro Roofing INC | Hadley Eric Hoff | — | (925) 684 7501 | Other roofers | Brentwood · Contra Costa County | — | — |
| Calpro Solar | Calpro Solar | office@calpro.solar | (925) 420 1006 | Other roofers | Brentwood · Contra Costa County | — | — |
| Calseismic Construction INC | Brandon Lewis Scura | — | (510) 621 4524 | GC, remodel, ADU | Martinez · Contra Costa County | — | — |
| Caltron Groups INC | Emily Ngan Ha Tang | — | (925) 575 7376 | GC, remodel, ADU | Danville · Contra Costa County | — | — |
| Calvin C Craig Landscaping | Calvin C Craig Landscaping | — | (925) 935 5269 | Windows, patio, painters | Pleasant Hill · Contra Costa County | — | — |