| Complete Leak Detection | Complete Leak Detection | completeleakdetection@msn.com | (707) 422 5586 | Pool | Fairfield · Solano County | — | — |
| Complete Plumbing Services | Villalpando Salvador | — | (707) 803 1379 | Other | Fairfield · Solano County | — | — |
| Complete Plumbing Works | Complete Plumbing Works | — | (707) 590 0261 | Other | Vallejo · Solano County | — | — |
| Concentric Concrete INC | Christopher Michael Chan | arcconcreteinc@gmail.com | (707) 673 4614 | Other | Suisun · Solano County | — | — |
| Concrete Concepts And Design INC | Kenneth Ralph Rhodes | — | (415) 200 7075 | GC, remodel, ADU | Fairfield · Solano County | — | — |
| Connect Cate Cabling INC | Kevin Marc Lopez | — | (510) 367 9412 | Other | Fairfield · Solano County | — | — |
| Consolidated Lock INC DBA Consolidated Security Systems | Ronald Jay Pedroni | — | (510) 450 9100 | Alarm and generators | Vacaville · Solano County | — | — |
| Consolidated Networks Corporation | Brian Eugene Baesler | — | (707) 422 0791 | Other | Vacaville · Solano County | — | — |
| Construction & Design Services | Dominic Alexander Navarro | interested@domainmarket.com | (415) 905 0078 | GC, remodel, ADU | Fairfield · Solano County | — | — |
| Construction Concierge INC | Rodriguez Salvador | — | (707) 330 8234 | Electricians | Vacaville · Solano County | — | — |
| Construction Covenants INC | Ronald Ray Mankini | — | (707) 864 0650 | GC, remodel, ADU | Fairfield · Solano County | — | — |
| Construction Solutions | Vincent Michael De La Torre | — | (707) 816 2079 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Contract Flooring | Contract Flooring | — | (707) 249 6284 | Other | Dixon · Solano County | — | — |
| Contractor 2.0 INC | Esteban Abimael Molina | — | (707) 720 7826 | GC, remodel, ADU | Fairfield · Solano County | — | — |
| Converse Building Specialties | Converse Building Specialties | — | (707) 718 7485 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Cook's Kitchen And Bath INC | David Allen Cook | — | (707) 342 2820 | GC, remodel, ADU | Benicia · Solano County | — | — |
| Coolrite Heating And Air | Coolrite Heating And Air | — | (707) 624 0930 | HVAC | Vacaville · Solano County | — | — |
| Cooper's Tree Care | Cooper's Tree Care | — | (707) 249 7447 | Tree | Vacaville · Solano County | — | — |
| Coopwood Construction And Remodeling | Rex Michael Coopwood | — | (650) 388 2256 | GC, remodel, ADU | Benicia · Solano County | — | — |
| Copap LLC | Steven Stanley Parnell | — | (650) 318 7400 | GC, remodel, ADU | Fairfield · Solano County | — | — |
| Cope Builders | Robin Bruce Cope | — | (707) 689 4078 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Copper Mountain Plumbing INC | Gary Leon Jr Waldren | — | (707) 689 0766 | Other | Vacaville · Solano County | — | — |
| Copperfield Plumbing | Copperfield Plumbing | copperfieldplumbing@yahoo.com | (707) 290 7089 | Other | Fairfield · Solano County | — | — |
| Corado Builders INC | Edgardo Salvador Corado | — | (415) 871 8342 | GC, remodel, ADU | Benicia · Solano County | — | — |
| Cordoza Electric | Daniel Charles Cordoza | daniel@cordozaelectric.com | (707) 400 3219 | Electricians | Vacaville · Solano County | — | — |
| Corlan INC | Joseph Michael Smulan | — | (707) 373 8867 | Other | Benicia · Solano County | — | — |
| Cornerstone Concrete LLC | Santos Ortiz Fausto | — | (707) 862 1404 | Other | Vacaville · Solano County | — | — |
| Cornerstone Fence Company | David Tikhonchuk | interested@domainmarket.com | (413) 459 3097 | Other | Vacaville · Solano County | — | — |
| Cornwell Electric LLC | Daniel Paul Cornwell | — | (707) 642 8155 | Electricians | Vallejo · Solano County | — | — |
| Cost U Less Roofing LLC | Juan Rodriguez | — | (707) 429 3070 | Other roofers | Suisun City · Solano County | — | — |
| Costal Fire Protection INC | Jorge Luis Castro | — | (707) 333 2056 | Other | Vallejo · Solano County | — | — |
| Costume Craft Tile Company | Garcia Francisco | — | (707) 246 8293 | Other | Vallejo · Solano County | — | — |
| Cotter Painting LLC | Jon Michael Cotter | — | (530) 307 1460 | Windows, patio, painters | Vallejo · Solano County | — | — |
| Coughran Mechanical Services INC | Lenese Mae Coughran | coughran@frontiernet.net | (707) 374 2100 | Other | Rio Vista · Solano County | — | — |
| Counter Top Restoration Tile & Stone | Jeffrey Benjamin Prosser | — | (707) 580 3093 | Restoration | Vacaville · Solano County | — | — |
| Country Bear Electric INC | Mark Casey Jones | — | (707) 678 1869 | Electricians | Dixon · Solano County | — | — |
| Coyote Creek Construction | Daniel Buenrostro Gonzalez | — | (510) 750 6572 | GC, remodel, ADU | Fairfield · Solano County | — | — |
| Cozy Home Services | Gary Jason Grant | — | (707) 474 5097 | HVAC | Vacaville · Solano County | — | — |
| Craftsman Strong Builder | Craftsman Strong Builder | — | (925) 260 1428 | GC, remodel, ADU | Dixon · Solano County | — | — |
| Crandall Bates | Crandall Bates | — | (707) 853 3448 | GC, remodel, ADU | Vallejo · Solano County | — | — |