| 3 Ten Builders INC | Adam Paul Hammett | — | (805) 298 2254 | GC, remodel, ADU | Porter Ranch · Los Angeles County | — | — |
| 3 Ten Plumbing INC | John Darold Senesac | — | (310) 461 9691 | Other | Torrance · Los Angeles County | — | — |
| 3 Thirteen INC | Cole Ezekiel Kurimay | — | (888) 899 0011 | Other | Sacramento · Sacramento County | — | — |
| 3 Trades Construction | Hernandez Alejandro Martinez | — | (818) 619 1328 | GC, remodel, ADU | North Hills · Los Angeles County | — | — |
| 3 V Signs & Graphics LLC | Patric Gene Dacy | — | (310) 372 0888 | Other | Torrance · Los Angeles County | — | — |
| 3 Woodworkers INC | Jorge Oscar De Jesus Escorcia | — | (818) 518 3075 | Other | Northridge · Los Angeles County | — | — |
| 3-d Builders | 3-d Builders | — | (760) 914 0500 | GC, remodel, ADU | June Lake · Mono County | — | — |
| 3-d Construction | Darreld Edward Van Westrienen | — | (909) 980 5948 | GC, remodel, ADU | Rancho Cucamonga · San Bernardino County | — | — |
| 3-d Construction Services INC | Robert Camargo | — | (714) 488 8700 | GC, remodel, ADU | Orange · Orange County | — | — |
| 3-d Door Company INC | Mark Anthony Picco | — | (714) 625 0311 | Other | Placentia · Orange County | — | — |
| 3-d General Construction | Shillian Ramin | — | (310) 707 8445 | GC, remodel, ADU | Tarzana · Los Angeles County | — | — |
| 3-d Mobile Home Services INC | David Glenn Mckee | — | (760) 294 8209 | Other | Escondido · San Diego County | — | — |
| 3-d Plumbing | Glen William Dart | — | (707) 628 9947 | Other | Rio Vista · Solano County | — | — |
| 3-d Tree Services INC | Robert Camargo | — | (714) 844 4896 | Windows, patio, painters | Orange · Orange County | — | — |
| 3-k Roofing INC | Jesus Manuel Murguia | — | (408) 592 0939 | Other roofers | San Jose · Santa Clara County | — | — |
| 3-m Electric | Ramzy Ragheb Gundy | shea@m-electric.com | (310) 989 7309 | Electricians | Rancho Palos Verdes · Los Angeles County | — | — |
| 3-points Design+build INC | Lisa Ann Molgren | hello@rfuenzalida.com | (310) 513 5453 | GC, remodel, ADU | San Diego · San Diego County | — | — |
| 3-valley's Construction INC | Kelly Lynn| Lazenby Kelly Lynn Soiles | — | (909) 941 8440 | GC, remodel, ADU | Rancho Cucamonga · San Bernardino County | — | — |
| 3-ways Painting INC | Agustin Garcia-Garmendia | — | (415) 235 6952 | Windows, patio, painters | Cameron Park · El Dorado County | — | — |
| 3000 Construction | Enrique Hernandez Escareno | — | (310) 946 6643 | GC, remodel, ADU | Hawthorne · Los Angeles County | — | — |
| 301 Projects INC | Young Chul Kim | — | (213) 278 2899 | GC, remodel, ADU | Los Angeles · Los Angeles County | — | — |
| 310 Construction INC | Daniel Jose Torres | — | (844) 310 9050 | GC, remodel, ADU | Torrance · Los Angeles County | — | — |
| 310 Electric INC | Victor Alvarez | — | (310) 345 5612 | Electricians | Compton · Los Angeles County | — | — |
| 310 General Electrical | Cardenas Gabriel | — | (310) 254 5832 | Electricians | Los Angeles · Los Angeles County | — | — |
| 310 HVAC LLC | John Angel Castillo | — | (310) 902 0393 | HVAC | Mar Vista · Los Angeles County | — | — |
| 310 Plumbing INC | Ramirez Sergio | — | (310) 310 0113 | Other | Santa Monica · Los Angeles County | — | — |
| 311 Construction General Contractor | Perez Mario Silva | — | (951) 282 5196 | GC, remodel, ADU | Hemet · Riverside County | — | — |
| 313 Tec Solutions | 313 Tec Solutions | — | (916) 390 9603 | Other | Seal Beach · Orange County | — | — |
| 316 Builder | 316 Builder | — | (916) 869 0022 | Electricians | Newcastle · Placer County | — | — |
| 316 Engineering And Construction Co INC | John William Massie | — | (818) 395 7989 | GC, remodel, ADU | Rosemead · Los Angeles County | — | — |
| 316 Windows & Door Installers | 316 Windows & Door Installers | — | (661) 526 9786 | Windows, patio, painters | Lancaster · Los Angeles County | — | — |
| 31O Development INC | Santosuosso John | — | (310) 869 4745 | GC, remodel, ADU | Los Angeles · Los Angeles County | — | — |
| 32 Dimensions Maintenance INC | Don Dieu Thanh Ly | — | (949) 648 2490 | HVAC | Westminster · Orange County | — | — |
| 320 Grit INC | Brett Tyler Smith | — | (844) 320 4748 | GC, remodel, ADU | Irvine · Orange County | — | — |
| 321 Epoxy Coatings | Walter Alexander Guevara | — | (714) 376 6017 | Other | Tustin · Orange County | — | — |
| 321 Plumbing INC | Benito Estrada Chavez | — | (760) 215 9520 | Other | Escondido · San Diego County | — | — |
| 328 Construction INC | Zhao Young | — | (415) 823 7119 | Electricians | Daly City · San Mateo County | — | — |
| 33 Andrade Enterprises INC | Nicholas Francisco Andrade | — | (951) 634 2111 | GC, remodel, ADU | Temecula · Riverside County | — | — |
| 33 Landscapes INC | Adam Charles Bree | — | (916) 367 2963 | Windows, patio, painters | Visalia · Tulare County | — | — |
| 33rd INC | Marcos Anthony Rivas | — | (818) 805 3479 | GC, remodel, ADU | Chatsworth · Los Angeles County | — | — |