| Construction West Services INC | Alistair Robb Kettlewell | — | (925) 387 8177 | GC, remodel, ADU | Martinez · Contra Costa County | — | — |
| Contra Costa Builders LLC | Vladimir Levitansky | info@contracostabuilders.com | (323) 646 0756 | GC, remodel, ADU | El Cerrito · Contra Costa County | — | — |
| Contra Costa Carpenter INC | Danilo Bosio | — | (510) 859 5800 | GC, remodel, ADU | El Sobrante · Contra Costa County | — | — |
| Contra Costa Climate Control INC | Scott Conner Vargas | — | (925) 825 3131 | HVAC | Concord · Contra Costa County | — | — |
| Contra Costa Coatings | Contra Costa Coatings | — | (925) 766-8078 | Windows, patio, painters | San Ramon · Contra Costa County | — | — |
| Contra Costa Decks LLC | Daniel Joseph Frumenti | — | (925) 744 9313 | Windows, patio, painters | Martinez · Contra Costa County | — | — |
| Contra Costa Door Co | Justin Eugene Brooks | — | (925) 671 7888 | Other | Concord · Contra Costa County | — | — |
| Contra Costa Electric INC | James Gregory Moore | — | (925) 229 4250 | Electricians | Martinez · Contra Costa County | — | — |
| Contra Costa Fire Protection INC | Ismael Alejandro Martinez | — | (925) 446 7750 | Other | Pittsburg · Contra Costa County | — | — |
| Contra Costa Gates | Contra Costa Gates | info@contracostagates.com | (925) 954-9696 | Alarm and generators | Concord · Contra Costa County | — | — |
| Contra Costa Heating & Air Conditioning | Contra Costa Heating & Air Conditioning | — | (510) 632-7699 | HVAC | Pleasanton · Contra Costa County | — | — |
| Contra Costa Mosquito & Vector Control District | Contra Costa Mosquito & Vector Control District | — | (925) 685-9301 | Pest, tile roofs | Concord · Contra Costa County | — | — |
| Contra Costa Painting INC | Nelson Ernest Atkinson | nelsoncocopaint@yahoo.com | (925) 676 8713 | Windows, patio, painters | Concord · Contra Costa County | — | — |
| Contra Costa Plate & Mirror Co | Contra Costa Plate & Mirror Co | — | (800) 452-7789 | Windows, patio, painters | Pacheco · Contra Costa County | — | — |
| Contra Costa Plumbing | Contra Costa Plumbing | — | (925) 672 6533 | Electricians | Clayton · Contra Costa County | — | — |
| Contra Costa Properties Inc. | Contra Costa Properties Inc. | — | (925) 687-0111 | Property managers | Concord · Contra Costa County | — | — |
| Contra Costa Property Management | Contra Costa Property Management | info@contracostapm.com | (925) 338-9938 | Property managers | Concord · Contra Costa County | — | — |
| Contra Costa Roofworks INC | Edward Anthony Wojcik | — | (925) 766 0973 | Other roofers | Concord · Contra Costa County | — | — |
| Contra Costa Tear Off INC | Robert Paul Jensen | cctearoff@yahoo.com | (925) 827 0700 | Other roofers | Martinez · Contra Costa County | — | — |
| Contra Costa Termite Control | Contra Costa Termite Control | contracostatermite@gmail.com | (925) 680-7665 | Pest, tile roofs | Concord · Contra Costa County | — | — |
| Contra Costa Tree & Stump Removal | Bruce Elliot Adair | — | (415) 420 6464 | Tree | El Sobrante · Contra Costa County | — | — |
| Contra Costa Tree And Stump Removal | Contra Costa Tree And Stump Removal | bruceeadair@hotmail.com | (510) 669-9925 | Tree | Contra Costa · Contra Costa County | — | — |
| Contract Finish Floors INC | Lee Andrew Friedman | — | (925) 383 2065 | Other | Concord · Contra Costa County | — | — |
| Contreras Painting & Decorating | Contreras Painting & Decorating | — | (925) 521 4792 | Windows, patio, painters | Concord · Contra Costa County | — | — |
| Control Technology | Control Technology | — | (925) 381 2228 | Electricians | Concord · Contra Costa County | — | — |
| Controlled Access Gate Services | Steven Douglas Horrocks | — | (925) 758 3373 | Other | San Pablo · Contra Costa County | — | — |
| Conway Masonry | Conway Masonry | — | (650) 766 0343 | GC, remodel, ADU | Pleasant Hill · Contra Costa County | — | — |
| Cool Aire Systems INC | John Richard Jr Freschi | — | (510) 501 4092 | HVAC | Brentwood · Contra Costa County | — | — |
| Cooler Solutions INC | Gerald Leigh Mc Cutchen | office@jewelersguild.biz | (925) 303 2125 | HVAC | Antioch · Contra Costa County | — | — |
| Cooling And Heating Solutions | Flavio Ruben Guerrero | — | (888) 870 1166 | HVAC | Concord · Contra Costa County | — | — |
| Coolvu Of West Contra Costa | Coolvu Of West Contra Costa | — | (510) 327-8787 | Windows, patio, painters | San Pablo · Contra Costa County | — | — |
| Copper Mountain Electric | Sammy Walter Toy | — | (925) 813 2605 | Electricians | Antioch · Contra Costa County | — | — |
| Corbel Construction Co | Darouian Fereydoon | — | (510) 750 4418 | GC, remodel, ADU | Pleasant Hill · Contra Costa County | — | — |
| Corbett/salvador Construction INC | John Patrick Corbett | — | (925) 785 3493 | GC, remodel, ADU | Danville · Contra Costa County | — | — |
| Cordoba Painting | Cordoba Painting | — | (415) 305 4463 | Windows, patio, painters | Antioch · Contra Costa County | — | — |
| Core Build Group INC | Hector Enrique Mancera | — | (925) 383 0354 | GC, remodel, ADU | Danville · Contra Costa County | — | — |
| Core Construction Builders And Associates INC | Frank Beretes Jr Sampson | — | (925) 984 5156 | HVAC | San Ramon · Contra Costa County | — | — |
| Core Construction Resources | Joseph William Nehi | — | (925) 809 5149 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |
| Corey Enterprises INC | Bruce David Sr Corey | — | (510) 223 2361 | GC, remodel, ADU | El Sobrante · Contra Costa County | — | — |
| Corey Hegney | Corey Hegney | — | (408) 595 5288 | GC, remodel, ADU | San Ramon · Contra Costa County | — | — |