| 3 - D Painting | Dale Leedy Denlinger | — | (209) 872 6919 | Windows, patio, painters | Modesto · Stanislaus County | — | — |
| 3 A Contract Builders INC | Araceli Zambrano Esparza | — | (562) 307 2890 | GC, remodel, ADU | Lynwood · Los Angeles County | — | — |
| 3 A Plumbing | 3 A Plumbing | — | (415) 404 1400 | Other | San Bruno · San Mateo County | — | — |
| 3 A Roofing INC | Auscencio Alvarez Alvarez | info@aroofing.com | (714) 785 7378 | Other roofers | Costa Mesa · Orange County | — | — |
| 3 A Stone Tops INC | Adolfo Tal - Layo Bernabeo | — | (310) 800 8391 | Other | Carson · Los Angeles County | — | — |
| 3 A's Construction | Agustin Sr Gutierrez | — | (310) 350 3636 | GC, remodel, ADU | Long Beach · Los Angeles County | — | — |
| 3 At Once INC | Robert David Charles | — | (818) 521 0361 | GC, remodel, ADU | Woodland Hills · Los Angeles County | — | — |
| 3 B Construction INC | Jason Allan Burden | — | (209) 601 6716 | Electricians | Manteca · San Joaquin County | — | — |
| 3 Blind Brothers INC | Chris Alan Newbold | — | (916) 687 1071 | Other | Elk Grove · Sacramento County | — | — |
| 3 Blind Mice Window Coverings INC | Scot Thomas Dietz | — | (858) 452 6100 | Other | San Diego · San Diego County | — | — |
| 3 Boys Pro Painting INC | Gonzalez Leopoldo Ibarra | — | (559) 994 8718 | Windows, patio, painters | Fresno · Fresno County | — | — |
| 3 Bro's Roofing INC | Cesar Leonel Gomez Sarmiento | info@brosroofing.com | (905) 516-9515 | Other roofers | Quail Valley · Riverside County | — | — |
| 3 Brothers Construction Services | Abelardo Ivan Valenzuela-Cardenas | interested@domainmarket.com | (949) 510 2834 | GC, remodel, ADU | Lake Forest · Orange County | — | — |
| 3 Brothers Painting Corp | Jose Maria Catalan Tabarez | — | (714) 376 2940 | Windows, patio, painters | Anaheim · Orange County | — | — |
| 3 Brothers Plumbing INC | Gerardo Daniel Zuniga Meza | — | (909) 525 8153 | Other | Anaheim · Orange County | — | — |
| 3 C Building | 3 C Building | — | (415) 246 6994 | GC, remodel, ADU | Sebastopol · Sonoma County | — | — |
| 3 C Framing | 3 C Framing | — | (760) 297 8532 | Other | San Marcos · San Diego County | — | — |
| 3 C I Systems Integration INC | Anne Cunningham Campbell | — | (415) 285 2629 | Other | Woodside · San Mateo County | — | — |
| 3 C's Ornamental Iron Works | Javier Valencia Chavez | — | (408) 225 4100 | Other | Waterford · Stanislaus County | — | — |
| 3 Clover Group LLC | Jonathan Matthew Cheung | — | (424) 438 0380 | GC, remodel, ADU | Norwalk · Los Angeles County | — | — |
| 3 Color Flax Landscaping | 3 Color Flax Landscaping | — | (818) 581 8512 | Windows, patio, painters | Winnetka · Los Angeles County | — | — |
| 3 D Benchmark Builders INC | Joshua James Robnett | — | (916) 688 3500 | Electricians | Carmichael · Sacramento County | — | — |
| 3 D Construction INC | Joseph Elmer Kettle | — | (925) 519 8323 | GC, remodel, ADU | Dublin · Alameda County | — | — |
| 3 D Electric INC | Sanchez Diego | — | (951) 941 4391 | Electricians | Los Angeles · Los Angeles County | — | — |
| 3 D Environmental INC | Drew Paul Castro | — | (619) 546 0105 | GC, remodel, ADU | Spring Valley · San Diego County | — | — |
| 3 D G R Installations | Donald Gene Jr Ritter | — | (714) 525 4034 | Other | La Habra · Orange County | — | — |
| 3 D Green Plumbing | 3 D Green Plumbing | — | (209) 808 6807 | Other | Modesto · Stanislaus County | — | — |
| 3 D Plumbing | John Keith David | — | (209) 304 4911 | Other | Sutter Creek · Amador County | — | — |
| 3 D Plumbing | 3 D Plumbing | — | (650) 714 7692 | Other | Auburn · Placer County | — | — |
| 3 D Plumbing INC | Gregory Durand Des Baillets | — | (805) 443 4184 | Other | Thousand Oaks · Ventura County | — | — |
| 3 D Remodeling & Renovation | 3 D Remodeling & Renovation | — | (707) 816 2646 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| 3 Day Blinds LLC | Mbo LLC 3db | — | (949) 236 3540 | Other | Irvine · Orange County | — | — |
| 3 Day Kitchen & Bath | Oved Yakir | info@3day-kitchenbath.com | (619) 558 6950 | GC, remodel, ADU | San Diego · San Diego County | — | — |
| 3 Diamonds Construction INC | Juan Antonio Santoyo Lopez | — | (408) 648 6178 | GC, remodel, ADU | Modesto · Stanislaus County | — | — |
| 3 Dim Construction | Jose Felipe Padilla | — | (661) 645 5673 | GC, remodel, ADU | Canyon Country · Los Angeles County | — | — |
| 3 E Group INC | Brian Beauford Phelps | — | (818) 781 7171 | Other | Van Nuys · Los Angeles County | — | — |
| 3 E Solutions INC | Frank Joseph Sisca | — | (650) 773 2524 | Electricians | San Mateo · San Mateo County | — | — |
| 3 Edge Electric INC | Casas Silverio Navarrete | — | (626) 290 9118 | Electricians | Baldwin Park · Los Angeles County | — | — |
| 3 Element Fire Protection | 3 Element Fire Protection | — | (626) 497 2604 | Other | Rosemead · Los Angeles County | — | — |
| 3 Elements Heating & Cooling INC | Paul Samuel Mcgill | — | (209) 202 1000 | HVAC | Newman · Stanislaus County | — | — |