| C J Counter Installations | Jens Christian Jensen | — | (925) 695 5341 | Other | Brentwood · Contra Costa County | — | — |
| C J H Electrical Contractor | Chadi Joseph Hajjar | — | (415) 971 7827 | Electricians | Concord · Contra Costa County | — | — |
| C J H General Contractors | Christopher James Hayes | — | (925) 788 2997 | GC, remodel, ADU | Danville · Contra Costa County | — | — |
| C J W Landscape | Gregory James Wrenn | — | (925) 313 9025 | Windows, patio, painters | Martinez · Contra Costa County | — | — |
| C J's Roofing | Chris John Sr Montano | — | (925) 548 0932 | Other roofers | San Ramon · Contra Costa County | — | — |
| C K Construction | Christopher James Kearns | — | (951) 230 1906 | GC, remodel, ADU | El Sobrante · Contra Costa County | — | — |
| C K Riley Painting | C K Riley Painting | — | (925) 360 2523 | Windows, patio, painters | Concord · Contra Costa County | — | — |
| C L O Construction | Christian Leonard Oliver | — | (415) 710 4155 | GC, remodel, ADU | Point Richmond · Contra Costa County | — | — |
| C Lectric Company LLC | Christopher Ballantyne Langley | — | (925) 325 0117 | Electricians | Oakley · Contra Costa County | — | — |
| C M Construction | Christopher Todd Martinez | — | (925) 597 1204 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |
| C M E Construction INC | Charles Sterling Mc Dowell | inbox@cmeconstruction.com | (925) 381 7670 | Electricians | Clayton · Contra Costa County | — | — |
| C M Farr Metal Construction INC | Charles Michael Farr | — | (925) 820 8642 | Other | San Ramon · Contra Costa County | — | — |
| C M H Construction INC | Christopher Mark Hawke | — | (925) 389 6836 | GC, remodel, ADU | Danville · Contra Costa County | — | — |
| C M I Engineering & Construction | Michelle Lee Self | — | (925) 939 1378 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| C M Unlimited | C M Unlimited | — | (925) 917 1315 | Electricians | San Ramon · Contra Costa County | — | — |
| C M Wade Construction | Michael Anthony Wade | — | (925) 765 4509 | GC, remodel, ADU | Martinez · Contra Costa County | — | — |
| C M Works | C M Works | — | (510) 755 0297 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| C N D Construction Company INC | Carlos Alberto Sandoval Cameros | — | (925) 567 4200 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| C Overaa & Co | Gerald Donald Overaa | — | (510) 234 0926 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| C P Electric | Chris Peter Paicos | — | (925) 876 3724 | Electricians | Danville · Contra Costa County | — | — |
| C P Landscaping | C P Landscaping | — | (925) 628 4220 | Windows, patio, painters | Martinez · Contra Costa County | — | — |
| C R Fireline INC | Lynn Corinne | larric4@aol.com | (925) 685 9008 | Other | Pacheco · Contra Costa County | — | — |
| C R T Electrical | George Dimitrios Jr Georges | — | (415) 810 2821 | Electricians | Antioch · Contra Costa County | — | — |
| C S C Services | Set Olaf Candanosa | — | (925) 360 1559 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| C S Industrial Construction Management | Sena Cristofer | — | (925) 382 7387 | Other | Lafayette · Contra Costa County | — | — |
| C S Makela Construction | Craig Scott Makela | — | (925) 470 7181 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| C T B Fiber Optic Services INC | Paul Allen Barnard | — | (925) 481 2916 | Other | Pittsburg · Contra Costa County | — | — |
| C T E Group | Conrad Fabian Jansz | — | (510) 928 8411 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| C V W Properties | C V W Properties | — | (925) 280 9880 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| C W G Demolition & Hauling INC | Eric Geoffrey Tessem | — | (925) 788 6441 | Other | Danville · Contra Costa County | — | — |
| C Watkins Construction LLC | Christian Dennis Watkins | camille@cwatkinsconstruction.com | (925) 239 5694 | GC, remodel, ADU | Martinez · Contra Costa County | — | — |
| C&j Custom Casework INC | William Christopher Healey | — | (510) 774 8941 | Other | Oakley · Contra Costa County | — | — |
| C&n Construction Group INC | Alan Ngan | — | (415) 307 8820 | GC, remodel, ADU | Kensington · Contra Costa County | — | — |
| Ca Das Electric | Ryan Daniel Cano | — | (925) 212 7791 | Electricians | Danville · Contra Costa County | — | — |
| Ca Pacific Coast Construction & Restoration INC | James Curtis Johnston | — | (925) 684 9724 | GC, remodel, ADU | Bethel Island · Contra Costa County | — | — |
| Cab-tech | Phillip Messiah Soto | — | (925) 517 5456 | Other | Pittsburg · Contra Costa County | — | — |
| Cabinet Essentials INC DBA Otb Construction | Ovette Thomas Baluyut | — | (925) 550 6491 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |
| Cabinet Painting By Mike D | Cabinet Painting By Mike D | mike@cpbymd.com | (925) 917 1103 | GC, remodel, ADU | Martinez · Contra Costa County | — | — |
| Cabinets By Better Design | Cabinets By Better Design | — | (925) 586 3880 | GC, remodel, ADU | Martinez · Contra Costa County | — | — |
| Cabrera Construction | Cabrera Hernandez Samuel | — | (415) 359 5394 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |