| S Bliss Construction | Scott William Bliss | — | (925) 300 6085 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| S C Overhead Garage Door INC | Celso Saul | — | (510) 334 7346 | Other | San Pablo · Contra Costa County | — | — |
| S Costa Construction INC | Scott Michael Costa | scott.costa@comcast.net | (925) 829 6960 | GC, remodel, ADU | San Ramon · Contra Costa County | — | — |
| S D Electric INC | Steven Dale Hanson | — | (209) 832 0870 | Electricians | Brentwood · Contra Costa County | — | — |
| S E A M Construction INC | Scott Rocheleau | — | (925) 497 4107 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| S E Bright Construction Company | Steven Eugene Bright | — | (510) 566 5467 | GC, remodel, ADU | Danville · Contra Costa County | — | — |
| S E Clare Construction And General Contractor | Scott Ernest Clare | — | (925) 719 0614 | GC, remodel, ADU | Danville · Contra Costa County | — | — |
| S G C Plumbing | S G C Plumbing | steve@sgcplumbing.com | (925) 698 0514 | Other | Pittsburg · Contra Costa County | — | — |
| S G Construction Company | Scott Asdrubal Groschel | — | (925) 412 4944 | GC, remodel, ADU | Danville · Contra Costa County | — | — |
| S G S Incorporated | Larry Clinton Green | — | (650) 483 2961 | GC, remodel, ADU | Discovery Bay · Contra Costa County | — | — |
| S J N Construction | Stephanie Jean Nazzisi | — | (209) 649 7806 | GC, remodel, ADU | Discovery Bay · Contra Costa County | — | — |
| S J Wagner | S J Wagner | — | (925) 200 2002 | GC, remodel, ADU | Pittsburg · Contra Costa County | — | — |
| S K Builders | S K Builders | — | (510) 393 6955 | GC, remodel, ADU | El Sobrante · Contra Costa County | — | — |
| S K M Construction | Steven Keith Maestas | — | (925) 935 5854 | Other | Walnut Creek · Contra Costa County | — | — |
| S M Communications LLC | Martinez Salvador | — | (925) 752 1260 | Other | Antioch · Contra Costa County | — | — |
| S O S Roofing Co | George S Padilla | — | (925) 689 3310 | Other roofers | Concord · Contra Costa County | — | — |
| S Page & Son Painting INC | Jason Steven Page | — | (925) 766 0054 | Windows, patio, painters | Oakley · Contra Costa County | — | — |
| S R Construction And Landscape INC | Salcedo Reynaldo | — | (925) 787 2203 | GC, remodel, ADU | Martinez · Contra Costa County | — | — |
| S R M Electric | Reinhold Emanuel Lutz | — | (925) 719 0210 | Electricians | Antioch · Contra Costa County | — | — |
| S V Construction | Vafa Saied | kpccreativeconcepts@gmail.com | (925) 890 0456 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| S Woods Construction | Shaun Alan Woods | — | (925) 366 5432 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| S&s Shower Enclosures LLC | Branden Michael Stone | — | (925) 705 0946 | Windows, patio, painters | Oakley · Contra Costa County | — | — |
| S-tileing Renovation | S-tileing Renovation | — | (925) 899 1196 | GC, remodel, ADU | Pittsburg · Contra Costa County | — | — |
| S. A. Selover Construction Operations INC | Theresa Annette Selover | — | (925) 216 6406 | GC, remodel, ADU | Lafayette · Contra Costa County | — | — |
| S2serm LLC | Brian Robert Frantz | — | (925) 362 3041 | Other | Danville · Contra Costa County | — | — |
| Saavedra's Bay Area Construction | Brenda Y Rosales Membreno | — | (510) 712 4001 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| Saberi Design Build Consulting | Jamal Qasem Saberi | — | (415) 420 2013 | GC, remodel, ADU | Orinda · Contra Costa County | — | — |
| Saboo INC | Asghar Toheed | — | (626) 260 2849 | HVAC | Brentwood · Contra Costa County | — | — |
| Safe And Sound Security | Safe And Sound Security | — | (510) 640-8720 | Alarm and generators | Oakland · Contra Costa County | — | — |
| Safe And Sound Surveillance | Patrick Anthony Chown | — | (925) 369 5902 | Electricians | Walnut Creek · Contra Costa County | — | — |
| Safe Engineering Construction | Michael Mahmood Rasooly | — | (415) 747 1000 | GC, remodel, ADU | Oakley · Contra Costa County | — | — |
| Saga Quality Painting | Jesus Guillermo Cedeno Hernandez | — | (925) 848 8908 | Windows, patio, painters | Brentwood · Contra Costa County | — | — |
| Sagarchi Enterprises INC | Salim Shirmohammad Sagarchi | — | (408) 458 6670 | Electricians | Danville · Contra Costa County | — | — |
| Sage Woodworking INC | Brian Patrick O'malley | — | (415) 694 8454 | Other | Richmond · Contra Costa County | — | — |
| Sage Woodworks A Partnership | Gary Austin Demo | — | (415) 359 7925 | Other | Richmond · Contra Costa County | — | — |
| Saint's Mechanical | Saint's Mechanical | — | (925) 430 4079 | Other | Bay Point · Contra Costa County | — | — |
| Saitta's Gardening | Saitta's Gardening | — | (925) 516 2952 | Windows, patio, painters | Discovery Bay · Contra Costa County | — | — |
| Sak Builders INC | David Clifford Callis | — | (925) 602 6400 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Saki Brothers INC | Saki Karen Gharibian | — | (925) 383 2110 | HVAC | Concord · Contra Costa County | — | — |
| Salcedo's General Builder | Salcedo's General Builder | gustavo1al@hotmail.com | (925) 360 7179 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |