| #1 Son Plumbing INC | James Lincoln Stanfield | — | (909) 904 3774 | Other | Highland · San Bernardino County | — | — |
| 'a' Plumbing And Heating | Michael Robert Niez | — | (909) 585 5203 | HVAC | Big Bear City · San Bernardino County | — | — |
| 08 Landscaping INC | Juan Ruben Jr Consepcion | — | (760) 782 2190 | Windows, patio, painters | Hesperia · San Bernardino County | — | — |
| 1 - Step Up Electric | Verdugo Eduardo | — | (909) 725 1777 | Electricians | Redlands · San Bernardino County | — | — |
| 1 Dream Home Renovations | Ibarra Rafael Trujillo | dreamhomerenovations@myyahoo.com | (865) 661-1531 | GC, remodel, ADU | San Bernardino · San Bernardino County | — | — |
| 1 Teamwork Fire Protection LLC | Austin Allen Holmes | — | (909) 390 8392 | Other | Rancho Cucamonga · San Bernardino County | — | — |
| 10 Gauge Sheet Metal INC | Grant Wayne Grafius | — | (909) 560 7055 | Other roofers | Upland · San Bernardino County | — | — |
| 11 11 Heating And Cooling | 11 11 Heating And Cooling | — | (909) 728 0848 | HVAC | San Bernardino · San Bernardino County | — | — |
| 123 Construction | John William Jr Faber | — | (909) 941 5200 | GC, remodel, ADU | Rancho Cucamonga · San Bernardino County | — | — |
| 123 Construction LLC | John William Jr Faber | — | (909) 941 5200 | GC, remodel, ADU | Rancho Cucamonga · San Bernardino County | — | — |
| 138 Communications INC | Matthew George Schrum | — | (303) 378 1145 | Other | Upland · San Bernardino County | — | — |
| 1st Choice Air Solutions | Moises Rene Vanegas | — | (323) 667 4149 | HVAC | San Bernardino · San Bernardino County | — | — |
| 1st Choice Renovators LLC | Ignacio Jr Zamora | — | (909) 630 3936 | GC, remodel, ADU | Phelan · San Bernardino County | — | — |
| 1st Class Plumbing Repair Service INC | Perez Marcos | — | (909) 804 2476 | Other | San Bernardino · San Bernardino County | — | — |
| 2 R Drilling INC | Brian Craig Serl | — | (909) 490 0530 | Other | Chino · San Bernardino County | — | — |
| 2 Sharp | Steven Roy Sharpless | — | (951) 833 7800 | Other | Redlands · San Bernardino County | — | — |
| 21 Plumbing | 21 Plumbing | — | (909) 477 1600 | Other | Yucaipa · San Bernardino County | — | — |
| 210 Construction | James Anthony Jr Phillips | — | (909) 436 0596 | GC, remodel, ADU | Lake Arrowhead · San Bernardino County | — | — |
| 21st Century Painting And Waterproofing | 21st Century Painting And Waterproofing | — | (310) 365 0277 | Windows, patio, painters | Joshua Tree · San Bernardino County | — | — |
| 23 1/2 Hrs S O S Plumbing INC | Francisco Javier Macias | — | (626) 786 4999 | Other | Montclair · San Bernardino County | — | — |
| 23 Home Improvement | 23 Home Improvement | — | (310) 220 1999 | GC, remodel, ADU | Chino Hills · San Bernardino County | — | — |
| 24-7 Dock And Door Repair INC | Roberto Renteria Larios | — | (951) 205 4058 | Other | San Bernardino · San Bernardino County | — | — |
| 24/7 Carpet & Floor Care INC | Ziyad Saad Alfagir | — | (909) 363 6190 | GC, remodel, ADU | Redlands · San Bernardino County | — | — |
| 24/7 Plumbing & Rooter | 24/7 Plumbing & Rooter | — | (760) 780 9365 | Other | Victorville · San Bernardino County | — | — |
| 24/seven Electric | Joshua Roberto Paniagua | sevenelectric@gmail.com | (626) 848 3171 | Electricians | San Bernardino · San Bernardino County | — | — |
| 29 Palms Fencing | 29 Palms Fencing | — | (760) 367 6964 | Other | 29 Palms · San Bernardino County | — | — |
| 2nd Gen Glass LLC | Arthur Blake Gonzalez | — | (909) 372 2108 | Windows, patio, painters | Yucaipa · San Bernardino County | — | — |
| 3 N 1 Electric INC | Jose Luis Naranjo | — | (909) 562 0864 | Electricians | Chino · San Bernardino County | — | — |
| 3-d Construction | Darreld Edward Van Westrienen | — | (909) 980 5948 | GC, remodel, ADU | Rancho Cucamonga · San Bernardino County | — | — |
| 3-valley's Construction INC | Kelly Lynn| Lazenby Kelly Lynn Soiles | — | (909) 941 8440 | GC, remodel, ADU | Rancho Cucamonga · San Bernardino County | — | — |
| 360 Building Group Consulting INC | Cameron James Richartz | — | (909) 527 3435 | GC, remodel, ADU | Rancho Cucamonga · San Bernardino County | — | — |
| 360 Finish Carpentry LLC | Nathan David Ray Pawling | — | (909) 744 2074 | Other | Mentone · San Bernardino County | — | — |
| 3cm Corporation | Alexander Harvey Watts | — | (909) 534 1548 | GC, remodel, ADU | Loma Linda · San Bernardino County | — | — |
| 3D Stairs | 3D Stairs | — | (909) 749 1757 | Other | Adelanto · San Bernardino County | — | — |
| 3dxit Construction | Ricardo Castorena | — | (909) 262 4057 | GC, remodel, ADU | Fontana · San Bernardino County | — | — |
| 3rd Generation Roofing | Eric Benjamin Russell | — | (951) 206 2794 | Other roofers | Fontana · San Bernardino County | — | — |
| 3rs Construction Services INC | Reyes Rodriguez Ricardo | — | (909) 571 4515 | GC, remodel, ADU | Fontana · San Bernardino County | — | — |
| 4 - Ace Construction | Steven James Cooper | — | (909) 944 5400 | GC, remodel, ADU | Rancho Cucamonga · San Bernardino County | — | — |
| 4 - Ace Construction | Joseph Gilbert Jaramillo | — | (424) 506 0731 | GC, remodel, ADU | Rancho Cucamonga · San Bernardino County | — | — |
| 4 - Con Construction Services | Richard John Garabedian | — | (909) 322 4591 | GC, remodel, ADU | Upland · San Bernardino County | — | — |