| Scott Jaye | Scott Jaye | — | (707) 628 6892 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Scott May Construction | Scott Andrew May | — | (925) 383 5238 | GC, remodel, ADU | Benicia · Solano County | — | — |
| Scott R Hull Construction Company | Scott Robert Hull | — | (707) 326 6814 | GC, remodel, ADU | Benicia · Solano County | — | — |
| Sean Loughran | Sean Loughran | — | (707) 287 0774 | GC, remodel, ADU | Fairfield · Solano County | — | — |
| Sean Rattigan Construction | Rattigan Sean | contact@seanrattiganconstruction.com | (415) 240 0997 | GC, remodel, ADU | Benicia · Solano County | — | — |
| Sean Robbins | Sean Robbins | — | (530) 330 0344 | GC, remodel, ADU | Dixon · Solano County | — | — |
| Sem Incorporated | Shawn Edward Murphy | — | (510) 557 1511 | Electricians | Vacaville · Solano County | — | — |
| Senesac Window And Door Services | Joseph Mark Senesac | — | (707) 624 0242 | Windows, patio, painters | Vacaville · Solano County | — | — |
| Sensory Systems Group | Peter Steven Thatcher | — | (707) 747 1165 | Electricians | Benicia · Solano County | — | — |
| Serg On Concrete Co | Gonzalez Sergio | — | (707) 310 0694 | Other | Suisun City · Solano County | — | — |
| Sergio's Plumbing | Sergio's Plumbing | — | (707) 642 4769 | Other | Vallejo · Solano County | — | — |
| Serrao Electric | Gregory W Serrao | — | (707) 448 3670 | Electricians | Vacaville · Solano County | — | — |
| Shade Comforts INC | Constance Mae Moore | jason@ba-ws.com | (707) 746 5080 | GC, remodel, ADU | Benicia · Solano County | — | — |
| Shawn Gauthier Construction | Shawn Joseph Gauthier | — | (707) 249 4483 | GC, remodel, ADU | Dixon · Solano County | — | — |
| Shawn Gesell Construction | Shawn Steven Gesell | — | (707) 227 5612 | GC, remodel, ADU | Vallejo · Solano County | — | — |
| Sheldon West Builders INC | Leonard Odom Osborn | — | (707) 386 6198 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Shellooe Enterprises LLC | Tyler Bottero Shellooe | — | (408) 806 5004 | Other | Suisun City · Solano County | — | — |
| Shields Plumbing | Shields Plumbing | — | (707) 205 5844 | Other | Dixon · Solano County | — | — |
| Showcase Painting And Decorating | Mark Douglas Read | — | (707) 688 8402 | Windows, patio, painters | Fairfield · Solano County | — | — |
| Shrestha Construction | Shrestha Ojaswai | — | (415) 606 2797 | GC, remodel, ADU | Vallejo · Solano County | — | — |
| Shutters By Randy | Shutters By Randy | — | (408) 218 1766 | Other | Vallejo · Solano County | — | — |
| Sierra Bravo Construction | Gary Alan Stratton | — | (707) 689 7528 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Sierra Build Group | Ortiz Christopher Vasquez | — | (707) 631 7369 | GC, remodel, ADU | Suisun City · Solano County | — | — |
| Sierra Building Manintenance | Sierra Building Manintenance | — | (707) 426 1265 | Other | Fairfield · Solano County | — | — |
| Sierra Landscaping | Sierra Landscaping | — | (707) 310 6664 | Windows, patio, painters | Fairfield · Solano County | — | — |
| Sign Anatomy INC | James Mitsuo Nakamura | sales@signanatomy.com | (707) 446 4000 | Other | Vacaville · Solano County | — | — |
| Signal Solutions Corporation | Gregory Scott Richey | careers@signalsolutions.com | (707) 747 1100 | Other | Benicia · Solano County | — | — |
| Silverado Wallcovering | Silverado Wallcovering | brady@silveradowallcovering.com | (707) 480 9362 | Windows, patio, painters | Fairfield · Solano County | — | — |
| Silvermark Construction Services INC | Gregory Scott Owen | — | (707) 759 3434 | HVAC | Fairfield · Solano County | — | — |
| Simmons & Hutson Construction INC | Richard Lawrence Bergman-hutson | — | (707) 410 9754 | GC, remodel, ADU | Fairfield · Solano County | — | — |
| Simmons Electric | Leonard Patrick Simmons | — | (707) 685 6210 | Electricians | Vacaville · Solano County | — | — |
| Simply Handyworks | Simply Handyworks | simplyhandyworks@gmail.com | (707) 342 8405 | GC, remodel, ADU | Vallejo · Solano County | — | — |
| Simply Springs | Simply Springs | — | (707) 365 2419 | Other | Vacaville · Solano County | — | — |
| Sinaloa Painting Corp | Juliana Espinosa | — | (707) 631 9720 | Windows, patio, painters | Fairfield · Solano County | — | — |
| Sindt Power Services INC | Curtis Wilbur Sindt | — | (707) 648 0271 | Electricians | Vallejo · Solano County | — | — |
| Singh Construction | Singh Sarbjot | — | (707) 761 5104 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Site Electric Services | Brandon John Vanloon | — | (707) 653 0376 | Electricians | Vallejo · Solano County | — | — |
| Site Electric Services LLC | Brandon John Vanloon | — | (707) 653 0376 | Electricians | Vallejo · Solano County | — | — |
| Site Safe Traffic Safety And Signs | Chad Charles Lodel | — | (707) 419 9363 | Other | Vacaville · Solano County | — | — |
| Site Safe Traffic Support | Chad Charles Lodel | — | (707) 419 9363 | Other | Vacaville · Solano County | — | — |