| Skytrust Builder | Peterson Laranjeira Freitas | info@skytrustbuilder.com | (408) 716 3887 | GC, remodel, ADU | Hercules · Contra Costa County | — | — |
| Skyvision Construction INC | Anthony Baldwin Ortiz Juarez | — | (669) 264 6516 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Sl Electric | Lopez Samuel | sales@sl-electric.com | (415) 941 9753 | Electricians | San Pablo · Contra Costa County | — | — |
| Sl Plumbing And Remodeling | Sl Plumbing And Remodeling | — | (925) 565 5839 | GC, remodel, ADU | Pittsburg · Contra Costa County | — | — |
| Slingshot Drywall | Roberto Briseno Elizondo | roberto@slingshotdrywall.com | (925) 318 4957 | Other | Pittsburg · Contra Costa County | — | — |
| Sliwinski Company | Jarrad Lawrence Sliwinski | — | (925) 812 0875 | Windows, patio, painters | Pleasant Hill · Contra Costa County | — | — |
| Slovan Construction INC | Damian Svoboda | — | (925) 262 7496 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Slr International Corporation | Mohammad Reza Bazargani | — | (510) 451 1761 | Other | Walnut Creek · Contra Costa County | — | — |
| Sm Sykes General Contractor | Scott Millard Sykes | — | (925) 856 6320 | GC, remodel, ADU | Alamo · Contra Costa County | — | — |
| Smario Electric INC | Steven John Smario | — | (925) 383 4977 | Electricians | Walnut Creek · Contra Costa County | — | — |
| Smart Building INC | Gregory Moreton Ward | — | (510) 444 7678 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Smart Heating And Air Conditioning INC | Michael Joel Jestadt | — | (925) 450 2665 | HVAC | Concord · Contra Costa County | — | — |
| Smart Plumbing | Smart Plumbing | — | (415) 439 3312 | Other | Martinez · Contra Costa County | — | — |
| Smart Renovations INC | Thomas Crockett Allard | — | (510) 928 6669 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Smart Rooter | Smart Rooter | — | (510) 222 2297 | Other | El Sobrante · Contra Costa County | — | — |
| Smb Mechanical Solutions | Alexander Andrew Bayardo | — | (510) 912 6232 | HVAC | Brentwood · Contra Costa County | — | — |
| Smd Global LLC | Milan Ninkovic | — | (925) 405 7022 | GC, remodel, ADU | Pleasant Hill · Contra Costa County | — | — |
| Smi Demolition | Sebastiao Marcos Indalecio | — | (510) 206 4069 | Other | Richmond · Contra Costa County | — | — |
| Smi Demolition Company | Sebastiao Marcos Indalecio | — | (510) 812 9049 | Other | El Cerrito · Contra Costa County | — | — |
| Smith & Bernal Roofing | Cory Nicholas Smith | — | (925) 933 6461 | Other roofers | Walnut Creek · Contra Costa County | — | — |
| Smith & Son | Smith & Son | — | (925) 828 7434 | Windows, patio, painters | San Ramon · Contra Costa County | — | — |
| Smith & Son Construction | Peter Justin Ellis | — | (925) 387 0684 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |
| Smith's Pest Management | Smith's Pest Management | — | (408) 871-6988 | Pest, tile roofs | Concord · Contra Costa County | — | — |
| Smullen & Sons Excavation And Demolition | Michael Anthony Smullen | — | (510) 395 2847 | Other | Rodeo · Contra Costa County | — | — |
| Snb Plumbing | Snb Plumbing | — | (408) 839 4230 | Other | Danville · Contra Costa County | — | — |
| Snell Electric INC | Tibor Sarkany | — | (925) 820 5268 | Electricians | San Ramon · Contra Costa County | — | — |
| Sng Construction LLC | Viruk Tungpagasit | — | (510) 689 3557 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| Snowberry Landscapes | Bryan John Sutton | — | (510) 414 8425 | Windows, patio, painters | Richmond · Contra Costa County | — | — |
| Snowland Painter | Snowland Painter | — | (510) 328 0378 | Windows, patio, painters | El Cerrito · Contra Costa County | — | — |
| Soares Construction | Daniel Louis Soares | — | (510) 912 5515 | Other | San Ramon · Contra Costa County | — | — |
| Social Spaces | Social Spaces | — | (510) 867 3038 | Windows, patio, painters | Brentwood · Contra Costa County | — | — |
| Sogc Construction INC | Selvin Orlando Guevara | — | (415) 589 9499 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| Sohrab Nazari | Sohrab Nazari | — | (510) 384 7700 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Sok Construction Solutions | Vectra Henry Sok | — | (408) 460 8446 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |
| Solana Builder | Solana Builder | — | (925) 350 2898 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Solares House Movers Incorporated | Jose Guillermo Rubio | — | (925) 777 9053 | Other | Antioch · Contra Costa County | — | — |
| Solarpark Usa INC | Ya-Sin Norrise | sales@solarparkusa.com | (510) 483 7200 | Electricians | San Ramon · Contra Costa County | — | — |
| Solid Coat Painting | Solid Coat Painting | contact@sansoxygen.com | (925) 209 8562 | Windows, patio, painters | Martinez · Contra Costa County | — | — |
| Solid Rock Construction | Jason Allen Dingle | info@solidrockconstruction.com | (925) 383 2221 | GC, remodel, ADU | Oakley · Contra Costa County | — | — |
| Solid Tile | Solid Tile | — | (925) 839 7481 | Other | Martinez · Contra Costa County | — | — |