| Act Now Fire Inspections | Eric Albert Talistu | — | (855) 228 6699 | Other | Fairfield · Solano County | — | — |
| Action Asphalt | Shawn Christopher Peterson | info@actionasphalt.com | (707) 529 7478 | Other | Vacaville · Solano County | — | — |
| Ada Pro Construction | Arellano Arturo Hernandez | — | (510) 590 7506 | GC, remodel, ADU | Vallejo · Solano County | — | — |
| Adam Henry Construction | Adam Corey Henry | — | (707) 580 1249 | GC, remodel, ADU | Rio Vista · Solano County | — | — |
| Adam's Construction Co | Margarito Rodriguez Chavez | — | (707) 678 0514 | GC, remodel, ADU | Dixon · Solano County | — | — |
| Adams Engineering | Adams Engineering | — | (707) 678 0514 | Other | Dixon · Solano County | — | — |
| Adams Plumbing | Patrick Ryan Adams | — | (707) 880 8849 | Other | Vacaville · Solano County | — | — |
| Adolfo's Plumbing & Rooter LLC | Adolfo Ventura | — | (415) 624 4416 | Other | Fairfield · Solano County | — | — |
| Adval Construction | Adolfo Antonio Valencia Loza | — | (707) 704 7684 | GC, remodel, ADU | Vallejo · Solano County | — | — |
| Advance Asphalt INC | Brittany Buffy Wasso | — | (707) 543 2901 | Other | Vacaville · Solano County | — | — |
| Advanced Builders LLC | Estevan Edgar Torres | interested@domainmarket.com | (707) 330 5053 | GC, remodel, ADU | Suisun City · Solano County | — | — |
| Advanced Electrical & Telcom INC | Valery Alex Gores | — | (510) 548 0588 | Electricians | Vallejo · Solano County | — | — |
| Advanced Leak Detection Pool & Spa | Christian Joseph Scott | — | (707) 428 0308 | Pool | Vacaville · Solano County | — | — |
| Advanced Solutions & Services INC DBA Advanced Plumbing Heating | Danielle Nicole Fontaine | — | (707) 446 1800 | HVAC | Vacaville · Solano County | — | — |
| Advantage Paving & Grading | Amber Rose Peterson | — | (707) 628 9667 | Other | Dixon · Solano County | — | — |
| Aegis Painting | Aegis Painting | — | (707) 514 9923 | Windows, patio, painters | Vacaville · Solano County | — | — |
| Aer Construction | Alonzo Vivanco Ramirez | — | (916) 398 0448 | GC, remodel, ADU | Rio Vista · Solano County | — | — |
| Aet Consulting INC DBA Cozy Plumbing Services | Gary Jason Grant | — | (707) 474 5097 | Other | Vacaville · Solano County | — | — |
| Af Gardening INC | Alfredo Farias | — | (707) 853 2489 | Windows, patio, painters | Vallejo · Solano County | — | — |
| Affordable Home Improvement & Design INC | Joe Larry Gantt | — | (707) 372 5530 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Affordable Roofing | Guy C Tigner | gtaffordableroofing@gmail.com | (707) 529 2869 | Other roofers | Fairfield · Solano County | — | — |
| Affordable Seasons Landscaping Care | Affordable Seasons Landscaping Care | — | (707) 384 2198 | Windows, patio, painters | Fairfield · Solano County | — | — |
| Ag Elite Builders INC | Gonzalez Amando Ahumada | — | (510) 734 6234 | GC, remodel, ADU | Vallejo · Solano County | — | — |
| Ag Plumbing Co | Adolfo Alejandro Garcia Garcia | — | (707) 564 7209 | Other | Vacaville · Solano County | — | — |
| Agave Landscaping | Agave Landscaping | — | (707) 363 2508 | Windows, patio, painters | Fairfield · Solano County | — | — |
| Aguilar Roofing | Ubaldo Macedonio Aguilar | — | (707) 816 1924 | Other roofers | Fairfield · Solano County | — | — |
| Aguirre Reinforcing Steel LLC | Pablo Omar Aguirre | — | (707) 515 5587 | Other | Vallejo · Solano County | — | — |
| Ahl American Automatic Door Service | James Anthony Ahl | — | (707) 447 9518 | Other | Vacaville · Solano County | — | — |
| Air Essentials INC | Anthony Edward Pirrung | — | (707) 446 4080 | HVAC | Vacaville · Solano County | — | — |
| Air Exchange INC | Chris Koss | — | (707) 864 2700 | Other | Fairfield · Solano County | — | — |
| Air Tech Heating & Air Conditioning | Richard Wayne Jr Laughridge | — | (707) 330 7214 | HVAC | Vacaville · Solano County | — | — |
| Airelio HVAC Services INC | Aurelio Gernale Fabro | — | (707) 392 6761 | HVAC | Vacaville · Solano County | — | — |
| Ajero Construction | Joey Andre Ajero | — | (707) 655 7887 | GC, remodel, ADU | Vallejo · Solano County | — | — |
| Akash Construction | Ashok Pal Singh | — | (510) 304 6961 | Electricians | Vallejo · Solano County | — | — |
| Albert Pantoja | Albert Pantoja | — | (415) 450 8861 | GC, remodel, ADU | Fairfield · Solano County | — | — |
| Alder Creek Landscape | Alder Creek Landscape | — | (707) 365 7828 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Aldugrand Construction | Remon Farouk Wahballah | — | (323) 772 7476 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Aleco Electric INC | Peter James Alsbury | — | (800) 573 8803 | HVAC | Vacaville · Solano County | — | — |
| Alejandro Jimenez | Alejandro Jimenez | — | (707) 673 7147 | Electricians | Fairfield · Solano County | — | — |
| Alejandro's Plumbing | Alejandro's Plumbing | — | (707) 689 7930 | Other | Fairfield · Solano County | — | — |