| Creativo INC | Armando Cruz Ramirez | — | (707) 695 0566 | GC, remodel, ADU | Sebastopol · Sonoma County | — | — |
| Creedence Corporation | David Bernard Martin | — | (707) 765 9669 | GC, remodel, ADU | Petaluma · Sonoma County | — | — |
| Creo Builders | Kristen Marie Miller | projects@creo-builders.com | (707) 741 9647 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| Crh Painting | Crh Painting | — | (707) 228 8689 | Windows, patio, painters | Windsor · Sonoma County | — | — |
| Critchlow Builder | Critchlow Builder | — | (707) 934 0095 | GC, remodel, ADU | Sonoma · Sonoma County | — | — |
| Critical Control Restoration | Claudine Marcelle Syl Ripert | — | (707) 828 1180 | GC, remodel, ADU | Petaluma · Sonoma County | — | — |
| Cromwell Construction & Management INC | Jonathan Thomas Cromwell | — | (707) 310 1943 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| Crosetti & Lucero Engineering Contractor | Grace Rose Lucero | — | (707) 888 2649 | Other | Healdsburg · Sonoma County | — | — |
| Crow's Foot Construction | Shannon William Fry | — | (720) 212 3255 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| Crushing Excavation LLC | Christopher Paul Jr Rushing | — | (707) 280 5167 | Other | Petaluma · Sonoma County | — | — |
| Cruz Custom Cabinets | Cruz Custom Cabinets | jcruzdelangel2@gmail.com | (707) 703 2437 | Other | Rohnert Park · Sonoma County | — | — |
| Cruz Diaz Landscaping | Cruz Diaz Landscaping | — | (707) 364 9074 | Windows, patio, painters | Petaluma · Sonoma County | — | — |
| Cruz Lathing & Plastering INC | Miguel Angel Cruz | — | (415) 488 7400 | Other | Rohnert Park · Sonoma County | — | — |
| Crystal Construction INC | Martin Louis Espinosa | — | (707) 865 5157 | GC, remodel, ADU | Monte Rio · Sonoma County | — | — |
| Csc Flooring & Design | Craig Lyle Ross | — | (707) 800 7988 | Other | Rohnert Park · Sonoma County | — | — |
| Csn Builder | Csn Builder | — | (415) 599 6531 | GC, remodel, ADU | Petaluma · Sonoma County | — | — |
| Csn Electric | Chase Stuart Neal | nick@csnelectric.com | (707) 529 6338 | Electricians | Windsor · Sonoma County | — | — |
| Culinary Equipment Repair LLC | Graham Alan Robert Walling | — | (707) 820 5015 | Other | Santa Rosa · Sonoma County | — | — |
| Culligan Construction | Michael Joseph Culligan | — | (707) 338 9642 | GC, remodel, ADU | Petaluma · Sonoma County | — | — |
| Culvert Opps | Culvert Opps | — | (707) 236 7624 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| Cuneo Property Management | Cuneo Property Management | — | (415) 269-6432 | Property managers | Sonoma · Sonoma County | — | — |
| Cunningham Electric & Construction INC | David Thomas Cunningham | — | (707) 481 9870 | Electricians | Santa Rosa · Sonoma County | — | — |
| Curb Appeal Pros | Onaje Timothy Boone | %20lowpressurewash@gmail.com | (707) 910 7767 | GC, remodel, ADU | Guerneville · Sonoma County | — | — |
| Curious Measures Finish Carpentry & Cabinet Installation | Corinne Stacey Cherepak | — | (650) 350 0669 | Other | Forestville · Sonoma County | — | — |
| Curoso Plumbing INC | James Michael Curoso | — | (707) 545 5017 | Other | Santa Rosa · Sonoma County | — | — |
| Curran Environmental Services INC | Carol Ann Curran | — | (707) 529 6693 | GC, remodel, ADU | Petaluma · Sonoma County | — | — |
| Current F X | Current F X | — | (707) 338 3215 | Electricians | Petaluma · Sonoma County | — | — |
| Curry Landscaping INC | Scott David Curry | — | (707) 539 0578 | Windows, patio, painters | Santa Rosa · Sonoma County | — | — |
| Curt's Drywall | Curt's Drywall | — | (707) 584 5952 | Other | Rohnert Park · Sonoma County | — | — |
| Curtis Custom Building | Curtis Custom Building | — | (707) 762 1500 | GC, remodel, ADU | Petaluma · Sonoma County | — | — |
| Curtis Short Expert Pruning | Curtis Short Expert Pruning | — | (707) 528 8302 | Windows, patio, painters | Santa Rosa · Sonoma County | — | — |
| Custom Building Services INC | Sanchez Eulalio Herrera | — | (707) 704 3845 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| Custom Comfort Heating And Cooling INC | Pj Toste | — | (707) 486 9493 | HVAC | Geyserville · Sonoma County | — | — |
| Custom Design Countertops INC | Dennis William Green | — | (707) 579 9501 | Other | Santa Rosa · Sonoma County | — | — |
| Custom Housing Systems INC | Gary Dale Tatman | — | (707) 484 0444 | GC, remodel, ADU | Rohnert Park · Sonoma County | — | — |
| Custom Interior Trim And Cabinets | Custom Interior Trim And Cabinets | — | (707) 292 7012 | Other | Sonoma · Sonoma County | — | — |
| Custom Plumbing Of Northern California INC | Jerry Duane Jr Pedrioli | — | (707) 591 9901 | Other | Santa Rosa · Sonoma County | — | — |
| Custom Plumbing Systems | Custom Plumbing Systems | — | (707) 732 3363 | Other | Sebastopol · Sonoma County | — | — |
| Custom Quality Creations | Custom Quality Creations | — | (707) 685 7233 | Windows, patio, painters | Rohnert Park · Sonoma County | — | — |
| Custom Tractor Service | Neal Martin Carstensen | — | (707) 484 1931 | Other | Petaluma · Sonoma County | — | — |