| 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 | — | — |
| Sensible Builders Incorporated | Raymon Jon Vlado Bradbury | — | (510) 816 0653 | GC, remodel, ADU | Kensington · Contra Costa County | — | — |
| Sensley's Refrigeration | Sensley's Refrigeration | — | (925) 978 9632 | HVAC | Antioch · Contra Costa County | — | — |
| Sepulveda Landscaping | Sepulveda Landscaping | info@sepulvedalts.com | (925) 308 0563 | Windows, patio, painters | Brentwood · Contra Costa County | — | — |
| Sequoia Construction Services LLC | Matthew Roy Jensen | — | (925) 322 2626 | GC, remodel, ADU | Pleasant Hill · Contra Costa County | — | — |
| Sequoia Signs INC | Megan Cantini Schnurr | — | (925) 300 1066 | Other | Pacheco · Contra Costa County | — | — |
| Serafix Engineering Contractors INC | Larry Edward Brandt | — | (925) 552 8253 | Electricians | San Ramon · Contra Costa County | — | — |
| Serious Leisure Pools | Serious Leisure Pools | — | (925) 775 5722 | Pool | Brentwood · Contra Costa County | — | — |
| Service Pros Plumbers INC | Walker Jason | service@serviceprosplumbers.com | (925) 753 5600 | Other | Antioch · Contra Costa County | — | — |
| Servicexcel Heating And Air Conditioning | Abdul Samad Hakimi | — | (925) 344 2286 | HVAC | San Ramon · Contra Costa County | — | — |
| Setchko Construction | Dirk Stephen Setchko | — | (510) 812 5077 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| Seth Alexander | Seth Alexander | — | (415) 515 1761 | GC, remodel, ADU | Pinole · Contra Costa County | — | — |
| Seuss Flooring | Seuss Flooring | — | (925) 376 3000 | Other | Alamo · Contra Costa County | — | — |
| Seven Bridges Construction | Estevam Rogerio | — | (925) 787 4100 | GC, remodel, ADU | Pacheco · Contra Costa County | — | — |
| Sewer And Drain Masters Corporation | Ricardo Lopez Bonilla | — | (510) 222 7608 | Other | Richmond · Contra Costa County | — | — |
| Sewer Connection INC | Manuel Araujo Sousa | xe.iaso@techaro.lol | (775) 671 5637 | Other | El Sobrante · Contra Costa County | — | — |
| Sewer Solutions | Sewer Solutions | — | (925) 389 1872 | Other | Pittsburg · Contra Costa County | — | — |
| Sewer Works INC | Linda Maria Brazil | — | (510) 778 5259 | Other | Hercules · Contra Costa County | — | — |
| Sexton Heating & Air INC | Patrick Steven Sexton | — | (925) 783 0987 | HVAC | Brentwood · Contra Costa County | — | — |
| Seyed Abbas Hejrati | Seyed Abbas Hejrati | — | (650) 272 7174 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Sf Bay General Building | Larissa Goncalves Marques | info@sfbaygeneralbuilding.com | (510) 258 1143 | GC, remodel, ADU | Pinole · Contra Costa County | — | — |
| Sf Bay Plumbing | Sf Bay Plumbing | — | (415) 688-5358 | Other | San Pablo · Contra Costa County | — | — |
| Sf Crown Remodeling INC | Eduardo Montelongo | — | (415) 583 5205 | GC, remodel, ADU | San Pablo · Contra Costa County | — | — |
| Sf Mill Cabinets INC | Rafael Jr Montero Zamudio | anapbm@gmail.com | (415) 497 8557 | Other | Richmond · Contra Costa County | — | — |
| Sf Signature Builders INC | Rokay Jalal Mukhtar | — | (510) 359 8349 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |
| Sfc Electric Co INC | Milton Daniel Avila | — | (415) 580 9034 | Electricians | Concord · Contra Costa County | — | — |
| Sfe Electric INC | Pedro Felix Pereda | — | (925) 768 3390 | Electricians | Pittsburg · Contra Costa County | — | — |
| Sfr Builders INC | Saul Guadalupe Alvarez | — | (510) 367 4934 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| Sg Architectural Specialties | Miles Matthew Rolon | — | (877) 345 1276 | Other | Concord · Contra Costa County | — | — |
| Sgambati Painting Co INC | David Vincent Sgambati | — | (925) 787 8172 | Windows, patio, painters | Walnut Creek · Contra Costa County | — | — |
| Sgx Construction Services INC | Paul Gustave Dougherty | — | (925) 725 1805 | GC, remodel, ADU | Danville · Contra Costa County | — | — |
| Shadetech INC | William Joseph Lopak Mitchell | — | (707) 416 9993 | Other | Brentwood · Contra Costa County | — | — |
| Shahrzad Mansouri | Shahrzad Mansouri | — | (510) 499 4171 | GC, remodel, ADU | San Ramon · Contra Costa County | — | — |
| Shambala Construction INC | Peter Francis De Simone | — | (925) 470 0579 | GC, remodel, ADU | Discovery Bay · Contra Costa County | — | — |
| Shambhala Landscapes | Shambhala Landscapes | info@shambhalalandscapes.com | (415) 515 3436 | GC, remodel, ADU | Orinda · Contra Costa County | — | — |