| S G General Contractor | S G General Contractor | — | (707) 294 4925 | GC, remodel, ADU | Vallejo · Solano County | — | — |
| S H Mechanical INC | Carla Suzanne Vallejos | — | (707) 287 7982 | HVAC | Suisun City · Solano County | — | — |
| S J Construction | Jouzdani Sohrab | — | (707) 888 9618 | GC, remodel, ADU | Benicia · Solano County | — | — |
| S J R Construction | Stephen Joseph Ramblas | — | (707) 704 1100 | GC, remodel, ADU | Benicia · Solano County | — | — |
| S M C Construction | Steven Michael Cowley | — | (707) 322 0998 | GC, remodel, ADU | Fairfield · Solano County | — | — |
| S O S Plumbing Heating & Air | Charles Michael Mc Donald | — | (707) 745 3545 | HVAC | Benicia · Solano County | — | — |
| S O T Electric INC | Tafoya Salvador Ordonez | — | (510) 850 3941 | Electricians | Vallejo · Solano County | — | — |
| S P M Landscaping | S P M Landscaping | — | (707) 642 6068 | Windows, patio, painters | Vallejo · Solano County | — | — |
| S T Munson Construction INC | Ian James Lillibridge | — | (707) 864 3457 | GC, remodel, ADU | Fairfield · Solano County | — | — |
| S T R Building | S T R Building | — | (707) 207 0901 | GC, remodel, ADU | Fairfield · Solano County | — | — |
| S&f General Construction INC | Simon Nehemias Francisco Mateo | — | (510) 860 5446 | GC, remodel, ADU | Vallejo · Solano County | — | — |
| Safe Home Fire Protection | Safe Home Fire Protection | — | (707) 330 2734 | Other | Fairfield · Solano County | — | — |
| Safeguard Inspections | Safeguard Inspections | impallari@gmail.com | (707) 646-9072 | Inspectors | Fairfield · Solano County | — | — |
| Safehome Inspections INC | Safehome Inspections INC | — | (209) 327-2437 | Inspectors | Stockton · Solano County | — | — |
| Safety Home Inspectors Inc. | Safety Home Inspectors Inc. | — | (909) 936-9445 | Inspectors | Yucaipa · Solano County | — | — |
| Saitta Construction | Samuel David Saitta | — | (707) 761 6033 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Salazar Construction | Salazar Mendez Uriel | info@indiantypefoundry.com | (707) 334 3927 | GC, remodel, ADU | Vallejo · Solano County | — | — |
| Salinas Painting | Salinas Painting | — | (707) 515 9614 | Windows, patio, painters | Vallejo · Solano County | — | — |
| Salvador Godinez | Salvador Godinez | — | (415) 760 2745 | GC, remodel, ADU | Vallejo · Solano County | — | — |
| Salvador Sotelo DBA Spartan Construction Services | Sotelo Salvador | — | (707) 641 6171 | GC, remodel, ADU | Vallejo · Solano County | — | — |
| Sam's Landscaping Services | So Duy Dao | — | (707) 342 2239 | Windows, patio, painters | Vallejo · Solano County | — | — |
| San-mar Plumbing INC | Martin Sanchez | — | (530) 554 0454 | Other | Dixon · Solano County | — | — |
| Sanchez & Son Roofing INC | Saul Escalante Sanchez | — | (707) 373 3526 | Other roofers | Vallejo · Solano County | — | — |
| Sanchez Brother's Landscaping INC | Manuel De Jesus Torres Sanchez | — | (707) 334 8249 | Windows, patio, painters | Vallejo · Solano County | — | — |
| Sanchez Painting | Sanchez Painting | interested@domainmarket.com | (707) 761 6099 | Windows, patio, painters | Dixon · Solano County | — | — |
| Sandoval Marble & Granite | Marco Tulio Sandoval | — | (415) 378 7682 | Other | Vallejo · Solano County | — | — |
| Sanger Electric Corp | Victor Mark Sangervasi | — | (415) 328 5392 | Electricians | Vacaville · Solano County | — | — |
| Sanner Construction | Matthew Joseph Santos | — | (707) 469 3321 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Santos Electric Company INC | Adrian Santos | — | (707) 980 4629 | Electricians | Fairfield · Solano County | — | — |
| Saquelares Landscaping INC | Saquelares Lesther | lesther@saquelareslandscaping.com | (415) 342 8157 | Windows, patio, painters | Vallejo · Solano County | — | — |
| Saul Electric Company | Saul Alexander Artiga | — | (707) 437 6178 | Electricians | Vallejo · Solano County | — | — |
| Saul Silva's Construction LLC | Donald Leroy Ward | — | (707) 451 1841 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Scheunemann's Custom Flooring | Scheunemann's Custom Flooring | — | (707) 392 0887 | Other | Vacaville · Solano County | — | — |
| Schnell Construction | Thomas Michael Schnell | — | (707) 479 4708 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Schofield Custom Builder | Schofield Custom Builder | — | (707) 502 2870 | GC, remodel, ADU | Suisun City · Solano County | — | — |
| Schultz & Schultz Builders INC | Barry Eugene Schultz | — | (888) 755 2235 | Electricians | Dixon · Solano County | — | — |
| Schwarck Electric INC | Maxwell Bartlett Schwarck | — | (925) 488 2830 | Electricians | Fairfield · Solano County | — | — |
| Scotland Yards | Scotland Yards | — | (707) 761 4231 | Windows, patio, painters | Vacaville · Solano County | — | — |
| Scott Construction INC | Kerry Robert Scott | general@scott-construction.com | (707) 812 7215 | GC, remodel, ADU | Vallejo · Solano County | — | — |
| Scott Deane Construction | Scott Alan Deane | — | (707) 334 0392 | GC, remodel, ADU | Benicia · Solano County | — | — |