| Scott Loughran-smith Construction Plus | Scott Michael Loughran-smith | — | (925) 283 3941 | GC, remodel, ADU | Lafayette · Contra Costa County | — | — |
| Scott W Bryant DBA A I T | A I T | — | (925) 648 9906 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |
| Scott White Construction Company INC | Scott Edward White | — | (925) 766 2303 | GC, remodel, ADU | Pleasant Hill · Contra Costa County | — | — |
| Scott Wynn General Contracting | Scott Hollis Wynn | — | (510) 393 9979 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |
| Scottie Culclager Plumbing LLC | Scottie Laron Culclager | — | (650) 638 3308 | Other | Pittsburg · Contra Costa County | — | — |
| Scp Distributors LLC DBA Lincoln Aquatics | Charles Reeves Luecker | — | (925) 687 9500 | Pool | Concord · Contra Costa County | — | — |
| Scs Media INC | Farzam Tom Aliyar | — | (925) 525 6222 | Other | Walnut Creek · Contra Costa County | — | — |
| Sd Demolition Services | Sasha Gelain Di Domenico | — | (510) 913 5868 | Other | Richmond · Contra Costa County | — | — |
| Sd General Design & Construction Co | Chan Jevon | — | (808) 745 7575 | GC, remodel, ADU | Brentwood · Contra Costa County | — | — |
| Sd White Construction INC | Samuel David White | — | (510) 426 1854 | GC, remodel, ADU | Rodeo · Contra Costa County | — | — |
| Sdm Construction | Deyan Dinev Dinev | contact@sdmconstruction.com | (415) 610 0444 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Sdmi Construction INC | Santos Enrique Castillo | — | (925) 444 5550 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Sea Security Services Low Voltage | Yacine Boutrik | — | (760) 413 9138 | Electricians | Concord · Contra Costa County | — | — |
| Sead's Painting | Sead's Painting | — | (925) 323 6738 | Windows, patio, painters | Walnut Creek · Contra Costa County | — | — |
| Sealed Finish Caulking | Sealed Finish Caulking | — | (415) 518 4871 | Other | Richmond · Contra Costa County | — | — |
| Seaport Stainless | Linda Marie Doving | — | (510) 232 8687 | HVAC | Richmond · Contra Costa County | — | — |
| Searchlight Electric LLC | Peter Wayne Sanford | — | (925) 664 7832 | Electricians | Pittsburg · Contra Costa County | — | — |
| Searls And Son Builders INC | Kevin Robert Searls | — | (925) 963 8534 | GC, remodel, ADU | Martinez · Contra Costa County | — | — |
| Sebastian Francese General Contractor | Sebastian Francese General Contractor | — | (510) 290 6455 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| Sebastien Prioux Construction | Sebastien Carolin Prioux | — | (608) 707 7888 | GC, remodel, ADU | Pleasant Hill · Contra Costa County | — | — |
| Second Generation Tile | Second Generation Tile | — | (925) 370 0784 | Other | Martinez · Contra Costa County | — | — |
| Second Life Hardwood Floors INC | Cuevas Rodriguez Antonio | — | (925) 435 3238 | Other | Pacheco · Contra Costa County | — | — |
| Secret Garden Landscapes | Laura Elizabeth Osteen | cheryl@secretgardenlandscapes.com | (925) 330 3017 | Windows, patio, painters | Moraga · Contra Costa County | — | — |
| Secureorb Technologies | Ahmad Tamim Rastkar | — | (209) 412 8019 | Other | Antioch · Contra Costa County | — | — |
| Security Engineers INC | Hashemi Hamid | — | (925) 478 5707 | Electricians | Alamo · Contra Costa County | — | — |
| Seecon Financial & Construction Co INC | Albert Dominic Jr Seeno | — | (925) 671 7711 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Seecon Homes INC | Kathleen Marie Blackard | — | (925) 671 7711 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Segen Security INC | Temesgen Yemane Tesfay | info@segensecurity.com | (415) 866 0557 | Electricians | Bay Point · Contra Costa County | — | — |
| Segoviano Construction | Segoviano David | contact@segovianoconstruction.com | (510) 734 2985 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| Seismic Installations | Jerry Lynn Florence | — | (510) 504 5954 | Windows, patio, painters | Pleasant Hill · Contra Costa County | — | — |
| Seldia Design Construction | Steven Todd Dias | — | (888) 298 3335 | GC, remodel, ADU | Pinole · Contra Costa County | — | — |
| Select Craftsmanship General Contracting | Kerekes Zoltan | — | (510) 688 0625 | GC, remodel, ADU | Danville · Contra Costa County | — | — |
| Seles General Building Contractor | Seles General Building Contractor | — | (925) 305 8692 | GC, remodel, ADU | Bay Point · Contra Costa County | — | — |
| Selph Plumbing | Selph Plumbing | — | (925) 325 1869 | Other | Oakley · Contra Costa County | — | — |
| Selvin Painting | Selvin Painting | — | (616) 773 9224 | GC, remodel, ADU | San Pablo · Contra Costa County | — | — |
| Semik Oungoulian | Semik Oungoulian | — | (925) 595 0800 | GC, remodel, ADU | Orinda · Contra Costa County | — | — |
| Semper Fidelis Construction INC | Vishal Arun Naik | — | (858) 829 7328 | GC, remodel, ADU | Moraga · Contra Costa County | — | — |
| Semper Paratus Electrical | Justin Paul Houde | — | (650) 303 7002 | Electricians | Pleasant Hill · Contra Costa County | — | — |
| Seng's Plumbing | Seng's Plumbing | — | (510) 695 7731 | Other | Richmond · Contra Costa County | — | — |
| Seno Construction INC | Senad Braco Kasumovic | — | (925) 584 1245 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |