| Clyde Miles Construction Co INC | Stephanie Rose Seeno-Miles | — | (925) 427 4473 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Cm2 & Associates INC | Abran Gonzalez | — | (510) 509 0380 | Other roofers | San Ramon · Contra Costa County | — | — |
| Cmo Pavers INC | Hanniel Oliveira Rego | — | (510) 829 0504 | Other | Hercules · Contra Costa County | — | — |
| Coast Remodeling And Construction INC | Stephen Earl Mink | — | (510) 377 0129 | GC, remodel, ADU | Alamo · Contra Costa County | — | — |
| Coastal Bound INC DBA Cypress Plumbing | Scott Woodland Parkinson | — | (925) 777 9519 | Other | Antioch · Contra Costa County | — | — |
| Coastal Elite Roofing | Coastal Elite Roofing | — | (442) 419-1090 | Other roofers | Oceanside · Contra Costa County | — | — |
| Coastal Painting And Waterproofing | Coastal Painting And Waterproofing | — | (925) 698 9136 | Windows, patio, painters | Bay Point · Contra Costa County | — | — |
| Coastwide Electric INC | Hadzic Miralem | — | (408) 500 9622 | Electricians | Antioch · Contra Costa County | — | — |
| Coat Masters Painting INC | Sheryl Lynn Shaw Martinez | coatmasterspainting@gmail.com | (925) 565 3701 | Windows, patio, painters | Brentwood · Contra Costa County | — | — |
| Coats Plumbing | Coats Plumbing | — | (925) 352 5115 | Other | Pittsburg · Contra Costa County | — | — |
| Coco County Glass | Coco County Glass | — | (925) 248 7852 | Windows, patio, painters | Martinez · Contra Costa County | — | — |
| Cocos Excavating | Cocos Excavating | — | (925) 588 3277 | Other | Brentwood · Contra Costa County | — | — |
| Code Red Communications INC | Bryon Stephen Graves | — | (925) 307 7700 | Electricians | Discovery Bay · Contra Costa County | — | — |
| Cohen Painting | Cohen Painting | — | (510) 233 7020 | Windows, patio, painters | Richmond · Contra Costa County | — | — |
| Cold Storage Builders INC | Shane Najam Modad | shane@coldstoragebuilders.com | (925) 997 3413 | HVAC | Danville · Contra Costa County | — | — |
| Cold Temp Solutions | Bruce Elliott Golding | coldtempsolutions@gmail.com | (925) 374 4014 | HVAC | Martinez · Contra Costa County | — | — |
| Cole's Interior Design Center INC | Zachary Cole Rease | — | (925) 691 3920 | Other | Pleasant Hill · Contra Costa County | — | — |
| Coleman Cosby Landscape Design And Installation | Coleman Wesley Cosby | — | (415) 606 7993 | Windows, patio, painters | Richmond · Contra Costa County | — | — |
| Colindres Roofing Co | Carlos Humberto Colindres Gamez | — | (818) 381 0395 | Other roofers | San Pablo · Contra Costa County | — | — |
| Coloma Electric Heating & Air | Burton Alan Coloma | — | (925) 683 6281 | HVAC | Pleasant Hill · Contra Costa County | — | — |
| Color Rush Painting INC | Diego Roman Duenas | sales@colorrushpainting.com | (925) 325 5593 | Windows, patio, painters | Antioch · Contra Costa County | — | — |
| Color Touch Painting INC | Todd Alfred Worsfold | — | (415) 469 7261 | Windows, patio, painters | San Ramon · Contra Costa County | — | — |
| Color Vision Painting Jr INC | Juan Manuel Rivas Hernandez | — | (707) 631 2765 | Windows, patio, painters | Antioch · Contra Costa County | — | — |
| Comfort Home Heating & Air | Comfort Home Heating & Air | — | (510) 837 1620 | HVAC | San Pablo · Contra Costa County | — | — |
| Comfortpro Heating & Cooling INC | Kevinn Eduardo Velasquez-perez | — | (925) 497 2553 | HVAC | Pittsburg · Contra Costa County | — | — |
| Comletric INC | Matthew Edward Haynes | — | (925) 698 2219 | Electricians | Concord · Contra Costa County | — | — |
| Command Plumbing INC | Jesus Cervantes | — | (208) 934 3949 | Other | Antioch · Contra Costa County | — | — |
| Commercial Electric & Life Safety Systems INC | Kelvin Michael Crews | — | (925) 288 9801 | Electricians | Concord · Contra Costa County | — | — |
| Commercial Glass & Aluminum INC | Edward Ray Jr Wilkerson | — | (925) 427 0456 | Windows, patio, painters | Pittsburg · Contra Costa County | — | — |
| Commercial Lathing And Plastering INC | Joseph Gregory Mcgill | — | (925) 206 8205 | Other | Martinez · Contra Costa County | — | — |
| Compare Heating Air Conditioning And Sheet Metal | Albert Maek Fraschieri | — | (925) 686 1366 | HVAC | Concord · Contra Costa County | — | — |
| Complete Care Heating And Air Conditioning INC | Ian Richard Ils | — | (925) 570 1603 | HVAC | Concord · Contra Costa County | — | — |
| Complete Care Landscaping INC | Mcgiffin Aengus | — | (415) 710 6495 | Windows, patio, painters | El Cerrito · Contra Costa County | — | — |
| Complete HVAC Systems INC | Stephen Anthony Cordova | — | (209) 872 9964 | HVAC | Antioch · Contra Costa County | — | — |
| Complete Plumbing | Complete Plumbing | — | (925) 676 6969 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Complete Plumbing And Construction | Rafi Petrossian | — | (925) 676 6969 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Complete Pool Service And Repairs | Jasvir Singh Sahota | — | (925) 765 4035 | Pool | San Ramon · Contra Costa County | — | — |
| Compton Construction | Michael Kevin Compton | — | (650) 906 7574 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |
| Comtech Electric | Gregory Vahe Karakashian | — | (925) 876 0482 | Electricians | Walnut Creek · Contra Costa County | — | — |
| Concept Builders | Concept Builders | — | (925) 768 4983 | GC, remodel, ADU | Lafayette · Contra Costa County | — | — |