| 5th Generation Plumbing | 5th Generation Plumbing | — | (916) 470 3132 | Other | Rocklin · Placer County | — | — |
| 5thcsi | Linda Posada Rivera | lindarivera@5thcsi.com | (619) 651 5110 | GC, remodel, ADU | San Diego · San Diego County | — | — |
| 5trades INC DBA 5trades Construction | Ramsey Emad Khedr | ramsey@5tradesconstruction.com | (619) 909 4242 | GC, remodel, ADU | San Diego · San Diego County | — | — |
| 6 - 8 - 10 Construction INC | Gary John Walberg | — | (626) 695 6176 | GC, remodel, ADU | Chatsworth · Los Angeles County | — | — |
| 6 Hands LLC | Konrad Wolfgang Thieme | — | (805) 491 5377 | Other | Moorpark · Ventura County | — | — |
| 6 Point Construction | Richard Allen Evans | — | (530) 643 0891 | GC, remodel, ADU | Yreka · Siskiyou County | — | — |
| 6 Rivers Construction INC | Zane Eldon Jr Grant | arielle.pennington@riversconstruction.com | (530) 515 7563 | Other | Hoopa · Humboldt County | — | — |
| 6 Rivers Electric | Peter Raymond Dauphinee | — | (707) 616 4781 | Electricians | Blue Lake · Humboldt County | — | — |
| 6 Stars Engineering | 6 Stars Engineering | — | (760) 755 4951 | Windows, patio, painters | Lakeside · San Diego County | — | — |
| 6-2 Plumbing INC | Sixto Pablo Velazquez | — | (619) 894 3721 | Other | El Cajon · San Diego County | — | — |
| 60 Hertz Electric | Nigel Lowel Fluharty | 60hertzelectric@gmail.com | (510) 599 6565 | Electricians | Sonora · Tuolumne County | — | — |
| 601 Metals | 601 Metals | kelly.crawford@solidcounsel.com | (530) 412 1344 | Other | Truckee · Nevada County | — | — |
| 615 Grove Street INC DBA Rush Creek Construction | Mark Andrew Anderson | — | (805) 440 0720 | GC, remodel, ADU | San Luis Obispo · San Luis Obispo County | — | — |
| 619 Construction | Johann Lester Hernandez Oblitas | — | (323) 794 4361 | GC, remodel, ADU | San Diego · San Diego County | — | — |
| 619 Electric | Mitchell Clark Vansant | — | (805) 444 5758 | Electricians | San Diego · San Diego County | — | — |
| 619 Heating And Air | 619 Heating And Air | — | (619) 616 5538 | HVAC | Chula Vista · San Diego County | — | — |
| 619 Painting | 619 Painting | — | (619) 992 5696 | Windows, patio, painters | Spring Valley · San Diego County | — | — |
| 619 Remodels | 619 Remodels | guy@infinitydesignbuild.com | (619) 763 8363 | GC, remodel, ADU | Lakeside · San Diego County | — | — |
| 619 Roofing LLC | Eric Christopher Lopez | — | (619) 609 0214 | Other roofers | San Marcos · San Diego County | — | — |
| 619 Santa Drywall INC | Daria Moreno | — | (619) 551 0592 | Other | Lemon Grove · San Diego County | — | — |
| 619-m Floor Covering | 619-m Floor Covering | — | (619) 791 5859 | Other | National City · San Diego County | — | — |
| 625 St Clair Development Incorporated | Timothy Hawkins | — | (510) 686 0858 | GC, remodel, ADU | Brentwood · Contra Costa County | — | — |
| 626 Plumbing INC | Lu Paul | — | (626) 650 3003 | GC, remodel, ADU | Chino Hills · San Bernardino County | — | — |
| 64 Coatings | 64 Coatings | — | (559) 805 4651 | Windows, patio, painters | Tulare · Tulare County | — | — |
| 646 Construction Services | Fernando Mazkiaran Martinez | — | (951) 545 5390 | GC, remodel, ADU | Corona · Riverside County | — | — |
| 65 Construction | Antonio Chavez Carrillo | — | (408) 515 6458 | GC, remodel, ADU | San Jose · Santa Clara County | — | — |
| 661 Electric | Raymond Mondo Moreno | — | (661) 481 0090 | Electricians | Santa Clarita · Los Angeles County | — | — |
| 661 Tile & Stone INC | Adam David Gragg | — | (661) 406 4408 | Other | Acton · Los Angeles County | — | — |
| 680 Home Repair.com | Jason Sangku Pak | — | (510) 364 1214 | Electricians | San Ramon · Contra Costa County | — | — |
| 680 Home Repairs | Steve Hyun Lee | — | (510) 364 1214 | Electricians | San Ramon · Contra Costa County | — | — |
| 686 Pro Painting INC | Daniel Aguirre | — | (562) 235 2960 | Windows, patio, painters | Long Beach · Los Angeles County | — | — |
| 689 Construction Master | Antwoine Demetrius Turner | — | (714) 293 0393 | GC, remodel, ADU | Aliso Viejo · Orange County | — | — |
| 6A Audio Video | Chance Kent Longworth | — | (714) 345 8107 | Other | Fountain Valley · Orange County | — | — |
| 6C Development INC | Charles Alexander Ebenhack | — | (951) 858 4870 | GC, remodel, ADU | Lake Elsinore · Riverside County | — | — |
| 6th Gen Masonry | 6th Gen Masonry | 6thgenmasonry@gmail.com | (831) 359 3849 | Other | Aptos · Santa Cruz County | — | — |
| 7 Bar 7 Fence | 7 Bar 7 Fence | — | (916) 479 6371 | Other | Jackson · Amador County | — | — |
| 7 Contractors | Rafael Idos Angeles | — | (209) 996 8746 | GC, remodel, ADU | Modesto · Stanislaus County | — | — |
| 7 Cs Design INC | Curtis Alan Secor | — | (760) 341 1151 | Other | Palm Desert · Riverside County | — | — |
| 7 Day Builders INC | Clarence Ellington | — | (630) 930 2473 | GC, remodel, ADU | Los Angeles · Los Angeles County | — | — |
| 7 Day Garage Doors And Gates INC | Brian Martin Zepeda | — | (805) 279 8203 | Other | Thousand Oaks · Ventura County | — | — |