| Continuum Property Maintenance INC | Gil Lackritz | — | (619) 871 4902 | Windows, patio, painters | Escondido · San Diego County | — | — |
| Contour Design Build INC | Jorge Humberto Beltran | guy@infinitydesignbuild.com | (619) 454 1610 | GC, remodel, ADU | San Ysidro · San Diego County | — | — |
| Contract Flooring INC | Monika Bodor Muhl | — | (760) 481 5003 | Other | San Diego · San Diego County | — | — |
| Contract Interior Service INC DBA The Installers | Pamela Louise Tetu | — | (619) 741 4078 | GC, remodel, ADU | Spring Valley · San Diego County | — | — |
| Contracting Concepts INC | Stephen Mark Goldberg | — | (619) 466 8895 | GC, remodel, ADU | San Diego · San Diego County | — | — |
| Contracting Concrete Constructors INC | Jon James Hoffman | — | (760) 290 7110 | Other | Poway · San Diego County | — | — |
| Contracting INC | Ted William Watson | — | (760) 685 3000 | GC, remodel, ADU | Carlsbad · San Diego County | — | — |
| Contracting Solutions | Michael Patrick Hallahan | buildzoomsupport@blockrenovation.com | (626) 344 6242 | Other roofers | El Cajon · San Diego County | — | — |
| Contractor Building Pros | Daryl Vernard Jr Releford | — | (717) 856 0543 | GC, remodel, ADU | San Diego · San Diego County | — | — |
| Contractors & Beyond LLC | Jay Abbott | info@contractorsandbeyond.com | (619) 488 4121 | GC, remodel, ADU | San Diego · San Diego County | — | — |
| Contractors Electrical Service INC | Donald Lee Parrish | — | (619) 454 1200 | Electricians | San Diego · San Diego County | — | — |
| Contreras Engineering & Remodeling INC | Manuel Romero Contreras | buildzoomsupport@blockrenovation.com | (619) 422 4747 | Electricians | Chula Vista · San Diego County | — | — |
| Contreras Landscape | Contreras Landscape | — | (619) 633 4415 | Windows, patio, painters | El Cajon · San Diego County | — | — |
| Control Tech INC | Rexford James Wait | — | (760) 599 0086 | Electricians | Vista · San Diego County | — | — |
| Controlled Access Sysyems | Controlled Access Sysyems | — | (619) 589 7552 | GC, remodel, ADU | La Mesa · San Diego County | — | — |
| Controlled Entrances Group | Matthew Robert Bell | — | (760) 749 1212 | Other | Valley Center · San Diego County | — | — |
| Controlled Entry Specialists INC | Michael David Chism | — | (619) 670 8100 | Other | Spring Valley · San Diego County | — | — |
| Controls Of Things | Controls Of Things | sales@controlsofthings.com | (858) 312 9906 | Electricians | Poway · San Diego County | — | — |
| Conveyor & Storage Solutions INC | Joshua Joel Elgan | — | (858) 717 0649 | Other | San Diego · San Diego County | — | — |
| Convoy West Cleanup Services | Benny Robert Mendez | — | (858) 569 0493 | Other | San Diego · San Diego County | — | — |
| Conway Development Company | Brian Joseph Conway | — | (619) 572 2207 | GC, remodel, ADU | San Diego · San Diego County | — | — |
| Cook And Solis Construction INC | Kay Cook | — | (760) 747 4900 | Windows, patio, painters | Escondido · San Diego County | — | — |
| Cook Construction & Design INC | Ronald Gene Cook | — | (619) 423 2424 | GC, remodel, ADU | Imperial Beach · San Diego County | — | — |
| Cook Construction INC | Stephen Lewis Cook | — | (760) 855 5486 | GC, remodel, ADU | Escondido · San Diego County | — | — |
| Cook Electrical | Darrel Wayne Cook | — | (619) 588 6714 | Electricians | El Cajon · San Diego County | — | — |
| Cooks Construction And Repair LLC | Alika Aguirre Cook | — | (760) 583 3711 | GC, remodel, ADU | Vista · San Diego County | — | — |
| Cookson Enterprises INC | Tony Lynn Cookson | — | (760) 839 2966 | Other | Escondido · San Diego County | — | — |
| Cool Blue HVAC | Cool Blue HVAC | steved@precision-ac.com | (619) 569 6987 | HVAC | Chula Vista · San Diego County | — | — |
| Cool Construction | Behzad Haghani Hafezi | jason@cool-construction.com | (619) 861 4954 | GC, remodel, ADU | San Diego · San Diego County | — | — |
| Cool Guys | Miguel Alexis Raymundo | efficiency_air@yahoo.com | (904) 481 6071 | HVAC | San Diego · San Diego County | — | — |
| Cool Hand Luke Heating & Air Conditioning | Luke Cameron Scandrett | — | (619) 540 4024 | HVAC | Pine Valley · San Diego County | — | — |
| Cool It Heat It INC | Caine Christopher Forbes | — | (858) 449 5987 | HVAC | Poway · San Diego County | — | — |
| Cool Roof Restorations Corp | Michael William Geatz | info@christianroofing.com | (858) 518 7184 | Other roofers | Spring Valley · San Diego County | — | — |
| Cool With Browns HVAC | Cool With Browns HVAC | steved@precision-ac.com | (619) 484 6132 | HVAC | San Diego · San Diego County | — | — |
| Coolfix Pro INC | Dmitrii Folomeev | danielchen7253@gmail.com.for | (619) 322 0763 | HVAC | San Diego · San Diego County | — | — |
| Coolmaster HVAC | Coolmaster HVAC | buildzoomsupport@blockrenovation.com | (619) 587 3736 | HVAC | Chula Vista · San Diego County | — | — |
| Coombs Construction Engineering | Jon Michael Coombs | — | (760) 738 9500 | Other | Escondido · San Diego County | — | — |
| Coop's Sheetmetal | Coop's Sheetmetal | — | (619) 873 5580 | Other | El Cajon · San Diego County | — | — |
| Cooper Demolition | Cooper Demolition | — | (619) 681 3793 | Other | San Diego · San Diego County | — | — |
| Cooper Electric | Keith Richard Sibert | contact@claycoelectric.org | (619) 579 6042 | Electricians | El Cajon · San Diego County | — | — |