| Besseghini Construction | James Wesley Besseghini | — | (707) 685 4166 | GC, remodel, ADU | Dixon · Solano County | — | — |
| Best Builders | Best Builders | — | (707) 688 0584 | GC, remodel, ADU | Benicia · Solano County | — | — |
| Best Concrete And Cement | Charles Patrick Whalen | — | (707) 914 1100 | Other | Benicia · Solano County | — | — |
| Best In The Bay Painting | Best In The Bay Painting | — | (707) 853 5227 | Windows, patio, painters | Vacaville · Solano County | — | — |
| Best Landscaping & Design | Best Landscaping & Design | — | (925) 787 5299 | Windows, patio, painters | Vallejo · Solano County | — | — |
| Best Wood Flooring Design | Best Wood Flooring Design | bwfdflooring@gmail.com | (530) 515 2523 | Other | Vacaville · Solano County | — | — |
| Betos Plumbing And Rooter | Norberto Lara | — | (510) 912 2303 | Other | Vallejo · Solano County | — | — |
| Bettencourt Construction INC | Michael Earl Bettencourt | — | (707) 287 4710 | GC, remodel, ADU | Fairfield · Solano County | — | — |
| Better Homes Construction | Bruce Noyes Hill | — | (925) 383 8140 | Electricians | Vacaville · Solano County | — | — |
| Better Homes Construction | Jamel David Hanna | — | (415) 305 0121 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Better Horizon Construction INC | Engin Salon | — | (707) 567 1092 | GC, remodel, ADU | Vallejo · Solano County | — | — |
| Big B Painting | Big B Painting | — | (707) 761 4931 | Windows, patio, painters | Vacaville · Solano County | — | — |
| Big D's Construction | Donovan Michael Moreno | — | (707) 416 3675 | GC, remodel, ADU | Vallejo · Solano County | — | — |
| Big Dog Plumbing LLC | Errol Derrick Denn Layton | — | (707) 880 5434 | Other | Vacaville · Solano County | — | — |
| Bill Aton Painting | Bill Aton Painting | — | (707) 396 2001 | Windows, patio, painters | Vallejo · Solano County | — | — |
| Bill Walsh & Sons Construction | William Urie Walsh | — | (415) 606 9374 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Biota Landscape | Biota Landscape | — | (510) 809 6345 | Windows, patio, painters | Vallejo · Solano County | — | — |
| Bl Flooring | Brandon A Lopez | — | (707) 372 9664 | Other | Fairfield · Solano County | — | — |
| Black Creek Construction | Frank Allen Jr Schwarzbach | — | (707) 720 9996 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Black Diamond Asphalt INC | Allison Patricia Ragan | gtaber@yahoo.com | (707) 448 9402 | Other | Vacaville · Solano County | — | — |
| Black Gold Paving & Grading | Black Gold Paving & Grading | — | (707) 761 0894 | Other | Vacaville · Solano County | — | — |
| Blackhawk Construction | Kenneth John Iii Mathison | info@blackhawk-construction.com | (707) 479 5011 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Blackhawk Drywall | Blackhawk Drywall | — | (707) 449 3944 | Other | Fairfield · Solano County | — | — |
| Blackhawk Painting Company INC | Thomas Eaton Jr Hughes | — | (707) 451 7872 | Windows, patio, painters | Vacaville · Solano County | — | — |
| Blakeney Construction | Jan-erik Domenic Paino | — | (916) 919 5691 | GC, remodel, ADU | Dixon · Solano County | — | — |
| Blanton Construction | Michael Christopher Blanton | — | (707) 429 3017 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Blessing Tree Service | David Albert Benjamin | — | (707) 980 0423 | Tree | Vallejo · Solano County | — | — |
| Blevins Electric Designs LLC | Konner Lee Blevins | — | (707) 227 8737 | Electricians | Vacaville · Solano County | — | — |
| Blevins Remodeling | Blevins Remodeling | info@blevinsremodeling.com | (707) 564 5379 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Blink Charging | Blink Charging | support@blinkcharging.com | — | EV chargers | Solano · Solano County | — | — |
| Bloomline Landscape & Lawncare INC | Roberto Federico Ramos Andrade | — | (707) 249 0180 | Windows, patio, painters | Dixon · Solano County | — | — |
| Blucor Demolition | Blucor Demolition | — | (510) 309 9077 | Other | Fairfield · Solano County | — | — |
| Blue Line Painting | Blue Line Painting | — | (415) 342 1211 | Windows, patio, painters | Vallejo · Solano County | — | — |
| Blue Mountain Construction Services INC | Stephanie Michele Maclean | — | (707) 451 8111 | HVAC | Vacaville · Solano County | — | — |
| Blue Pacific Heating & Air | Blue Pacific Heating & Air | — | (707) 280 4978 | HVAC | Vacaville · Solano County | — | — |
| Blue Star Construction | Cyrus Kourosh Morad | — | (707) 580 3001 | GC, remodel, ADU | Fairfield · Solano County | — | — |
| Blueridge Custom Pools | Blueridge Custom Pools | — | (707) 447 2102 | Pool | Vacaville · Solano County | — | — |
| Bluesky Heating And Air | Matthew Garrett Vallis | — | (510) 375 7839 | HVAC | Fairfield · Solano County | — | — |
| Bob's Lock And Safe | Robert Earl Kincheloe | — | (707) 678 2688 | Other | Dixon · Solano County | — | — |
| Bobbie Knowles Plumbing | Bobbie Knowles Plumbing | — | (510) 307 6603 | HVAC | Vallejo · Solano County | — | — |