| Underground Construction Co INC | Chad Elliott Hardesty | — | (707) 746 8800 | GC, remodel, ADU | Benicia · Solano County | — | — |
| Underground Electric Construction Company LLC | Stephen Michael Galagarza | — | (707) 746 8800 | Electricians | Benicia · Solano County | — | — |
| Unico Mechanical Corp | Randall Gordon Potter | info@unicomechanical.com | (707) 745 9970 | Other | Benicia · Solano County | — | — |
| Unique Concrete | Unique Concrete | — | (707) 689 6889 | Other | Vacaville · Solano County | — | — |
| Unique Scaffold | John Soto | — | (925) 446 4442 | Other | Benicia · Solano County | — | — |
| United Concrete Construction | Jose De Jesus Elias | — | (707) 207 1433 | Other | Fairfield · Solano County | — | — |
| United Heating And Air | United Heating And Air | — | (817) 386 6000 | HVAC | Dixon · Solano County | — | — |
| United Plumbing Services | Gustavo Genaro Cruz | interested@domainmarket.com | (510) 404 3363 | Other | Fairfield · Solano County | — | — |
| Universal Painting Contractors INC | Stephen Charles Fitzpatrick | — | (707) 427 0445 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Up 2 Code Plumbing INC | Michael Lawrence Pitta | — | (707) 751 1714 | Other | Benicia · Solano County | — | — |
| Up Building Construction INC | Ramon Ulises Pineda Beltran | — | (415) 533 3041 | GC, remodel, ADU | Vallejo · Solano County | — | — |
| Up Front Plumbing | Up Front Plumbing | — | (707) 439 5634 | Other | Suisun · Solano County | — | — |
| Up-2-date Plumbing Co | Anthony Curtis Nickens | — | (510) 565 9327 | Other | Vallejo · Solano County | — | — |
| Urban Edge Design Solutions | Urban Edge Design Solutions | inquire@urbanedgeds.com | (866) 500-7850 | Windows, patio, painters | Solana Beach · Solano County | — | — |
| Urban Fence | Urban Fence | urbanbuilds.ren@gmail.com | (707) 592 0868 | Other | Vacaville · Solano County | — | — |
| Urban Tree Care | Urban Tree Care | — | (707) 656 5596 | Tree | Vallejo · Solano County | — | — |
| Urbanlab Design And Metal Fabrication | Anthony Louis Orantes | — | (707) 562 8623 | Other | Vallejo · Solano County | — | — |
| Utrera Painting | Utrera Painting | info@utrerapainting.com | (707) 294 0256 | Windows, patio, painters | Vallejo · Solano County | — | — |
| V P P- Velez Professional Painting | Valez Garcia Sergio | — | (650) 722 1729 | Windows, patio, painters | Vallejo · Solano County | — | — |
| V Plumbing & Drain | Bernardo Callejo Vallejo | — | (408) 603 9837 | Other | Fairfield · Solano County | — | — |
| Vaca Valley Excavating & Trucking INC | Paul Angelo Guglielmoni | — | (707) 453 1812 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Vaca Vet Striping | Vaca Vet Striping | — | (707) 592 8331 | Other | Vacaville · Solano County | — | — |
| Vacaville Electric | Thomas Anthony Jackson | — | (707) 448 8222 | Electricians | Vacaville · Solano County | — | — |
| Vacaville Glass Company | Aaron Christopher Bolton | vacavilleglass@yahoo.com | (707) 448 6492 | Windows, patio, painters | Vacaville · Solano County | — | — |
| Vacaville Heating And Air Conditioning | Vincent Anthony Vedella | — | (707) 393 0106 | HVAC | Fairfield · Solano County | — | — |
| Valenciana Concrete And General Contractor INC | Luis Manuel Valencia Medina | — | (510) 478 2598 | GC, remodel, ADU | Vallejo · Solano County | — | — |
| Valentino Construction INC | Valentino Peter | — | (707) 425 1751 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Vallejo Electric Motor INC | Dillon Samuel Lightman | — | (707) 642 4315 | Electricians | Vallejo · Solano County | — | — |
| Vallejo Painting Services | Erika Nikole Ortega Rizo | — | (707) 373 7377 | Windows, patio, painters | Vallejo · Solano County | — | — |
| Valley Internet | Ofer Tenenbaum | service@valleyinternet.com | (707) 422 1200 | Other | Fairfield · Solano County | — | — |
| Valley Maintenance | Valley Maintenance | — | (707) 689 6252 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Valley Professional Painting | Valley Professional Painting | — | (707) 322 6970 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Valley Remodeling | Valley Remodeling | — | (707) 449 8563 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Van Blake Signature Garage Doors LLC | Gabriel Declaire Van Blake | — | (707) 386 0803 | Other | Benicia · Solano County | — | — |
| Van Dewark INC | Stephen Bruce Van Dewark | — | (707) 249 3344 | GC, remodel, ADU | Fairfield · Solano County | — | — |
| Van Pelt Construction Services | Mark Richard Van Pelt | — | (707) 438 3790 | GC, remodel, ADU | Fairfield · Solano County | — | — |
| Vance Christopher Berean | Vance Christopher Berean | — | (707) 326 6781 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Vanderpool Flooring | Vanderpool Flooring | — | (707) 301 5788 | Other | Vacaville · Solano County | — | — |
| Vapc Electric | Victor Andres Pastrana Cruz | — | (707) 514 9647 | Electricians | Suisun City · Solano County | — | — |
| Vargas Crafters Tile & Construction INC | Juan Vargas Franco | — | (415) 720 1172 | GC, remodel, ADU | Vallejo · Solano County | — | — |