| Cabrera General Contractor | Cabrera General Contractor | — | (510) 706 8034 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| Cadco Door & Window | Cadco Door & Window | — | (925) 383 9595 | Windows, patio, painters | Concord · Contra Costa County | — | — |
| Cadinha Landscaping & Design | Cadinha Landscaping & Design | — | (925) 899 3692 | Windows, patio, painters | Danville · Contra Costa County | — | — |
| Cal - Line Tree Care | Cal - Line Tree Care | — | (925) 329 2899 | Tree | Concord · Contra Costa County | — | — |
| Cal Bay Electric | Matthew Daniel Behrens | — | (925) 852 9825 | Electricians | Antioch · Contra Costa County | — | — |
| Cal Com Electric INC | Robert Dean Cupit | — | (925) 372 9015 | Electricians | Pittsburg · Contra Costa County | — | — |
| Cal Comfort | Cal Comfort | — | (510) 377 5662 | HVAC | Richmond · Contra Costa County | — | — |
| Cal Decking And Steel | Paul Salvador Villicana | — | (925) 338 3001 | Other | Antioch · Contra Costa County | — | — |
| Cal Helical Solutions INC | David Jimmy Fogleman | — | (925) 766 1377 | GC, remodel, ADU | Pittsburg · Contra Costa County | — | — |
| Cal Home Renovations LLC | Cheeling H Tsang | — | (707) 480 5393 | GC, remodel, ADU | San Pablo · Contra Costa County | — | — |
| Cal Management INC | Christopher Joseph Labbee | — | (925) 642 9557 | GC, remodel, ADU | Clayton · Contra Costa County | — | — |
| Cal Pacific Alarms | Cal Pacific Alarms | — | (510) 483 7513 | Electricians | Brentwood · Contra Costa County | — | — |
| Cal Painting | Cal Painting | — | (408) 482-1492 | Windows, patio, painters | Richmond · Contra Costa County | — | — |
| Cal Tec Electrical Systems | Justin William Keesler | — | (925) 354 2256 | Electricians | Concord · Contra Costa County | — | — |
| Cal Tech Security Services INC | Issa Shaker Odeh | — | (925) 383 8049 | Electricians | San Ramon · Contra Costa County | — | — |
| Cal-bay Communications | Cal-bay Communications | — | (415) 533 6253 | Other | Danville · Contra Costa County | — | — |
| Cal-delta Plumbing | Cal-delta Plumbing | david@caldeltaplumbing.com | (925) 234 6941 | Other | Pittsburg · Contra Costa County | — | — |
| Cal-neva Environmental Systems | Roger Arnold Deplazes | — | (925) 687 9980 | HVAC | Concord · Contra Costa County | — | — |
| Calbert's Electrical | Charley Jr Calbert | — | (925) 206 6696 | Electricians | Antioch · Contra Costa County | — | — |
| Calco Partners INC | Salvador Bustos Villa | — | (925) 768 6689 | Other | Martinez · Contra Costa County | — | — |
| Calcon Systems INC | Ryan Douglas Smith | connect@calcon.com | (925) 277 0665 | Electricians | San Ramon · Contra Costa County | — | — |
| Calgate Home Improvements INC | Mica Mergen Onon | — | (510) 860 8330 | GC, remodel, ADU | Hercules · Contra Costa County | — | — |
| Cali Climate Mechanical | Cali Climate Mechanical | — | (925) 305 3164 | HVAC | Brentwood · Contra Costa County | — | — |
| Cali Home Constructors | Carlos Ivan Calizaya Turpo | cict@calihomeconstructors.com | (510) 599 1085 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Cali HVAC INC | Daniel Ignat Anisimov | proof@cali-hvac.com | (925) 478 1746 | HVAC | Concord · Contra Costa County | — | — |
| Cali Plumbing & Rooter LLC | Hernandez David Ramirez | — | (925) 522 9750 | Other | Antioch · Contra Costa County | — | — |
| Cali Pro Fire Protection | Cali Pro Fire Protection | contact@caliprofireprotection.com | (415) 712 3401 | Other | Richmond · Contra Costa County | — | — |
| Cali Scaping | Cali Scaping | info@caliscaping.com | (925) 381 0669 | GC, remodel, ADU | Moraga · Contra Costa County | — | — |
| Cali Steel INC | Phillip Babe Babbitt | — | (925) 252 3327 | Other | Brentwood · Contra Costa County | — | — |
| Cali Water Heater & HVAC | Carl Johnny Fuller | — | (925) 723 1190 | HVAC | Brentwood · Contra Costa County | — | — |
| Cali Water Heater Solutions | Carl Johnny Fuller | — | (925) 723 1190 | Other | Brentwood · Contra Costa County | — | — |
| Calibuilders | Peter Sergeyevich Yaltanskiy | — | (714) 791-9857 | GC, remodel, ADU | Pleasant Hill · Contra Costa County | — | — |
| Calico California Constructores INC | Gaona Enrique Avila | — | (510) 932 9899 | GC, remodel, ADU | San Pablo · Contra Costa County | — | — |
| Caliel Interlocking Pavers INC | Itamar Leite Jr De Morais | — | (510) 282 3696 | Other | Pinole · Contra Costa County | — | — |
| Califa Tree Care INC | Jesus Carlitos Carbajal Diaz | — | (510) 815 5954 | Tree | Richmond · Contra Costa County | — | — |
| California Aesthetics INC | Jason Bradley Carter | — | (925) 382 2858 | GC, remodel, ADU | Orinda · Contra Costa County | — | — |
| California Air INC | Ronald Joseph Jr August | — | (925) 248 8117 | HVAC | Danville · Contra Costa County | — | — |
| California Aqua Pros INC | Gregory Lee Purkey | — | (925) 240 6262 | Pool | Discovery Bay · Contra Costa County | — | — |
| California Boiler Works Incorporated | Thomas Frederick Fakoury | — | (925) 584 8050 | HVAC | Clayton · Contra Costa County | — | — |
| California Building And Remodeling | California Building And Remodeling | — | (415) 756 7772 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |