| Straight Shot Plumbing | Straight Shot Plumbing | — | (925) 446 9868 | Other | Oakley · Contra Costa County | — | — |
| Straightline Fences | Straightline Fences | — | (925) 520 5556 | Windows, patio, painters | Antioch · Contra Costa County | — | — |
| Straightline Painting | Straightline Painting | interested@domainmarket.com | (925) 684 2898 | Windows, patio, painters | Bethel Island · Contra Costa County | — | — |
| Stranahan Tile | Stranahan Tile | — | (925) 339 4528 | Other | San Ramon · Contra Costa County | — | — |
| Strand Builders | Nina Louise Strand | — | (925) 330 5158 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Streamline Builders | Xiao Rong Wei | — | (415) 828 0135 | Electricians | Lafayette · Contra Costa County | — | — |
| Streamscapes | Peter Scott Cross | — | (530) 582 0371 | Windows, patio, painters | Discovery Bay · Contra Costa County | — | — |
| Stroer & Graff INC | Thea Ann Shupe | — | (925) 778 0200 | Other | Antioch · Contra Costa County | — | — |
| Stroke Of Genius Painting | Stroke Of Genius Painting | impallari@gmail.com | (510) 910 8454 | Windows, patio, painters | Richmond · Contra Costa County | — | — |
| Strong Tower Construction | Padilla Abel | — | (925) 381 3042 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |
| Strongbuilt Construction Company | Jose Humberto Flores | — | (415) 710 7246 | GC, remodel, ADU | San Pablo · Contra Costa County | — | — |
| Strope Industries INC | Cynthia Lynn Strope | — | (510) 410 5930 | GC, remodel, ADU | Danville · Contra Costa County | — | — |
| Stroud Development | Alexander Patrick Stroud | — | (925) 989 2048 | GC, remodel, ADU | Lafayette · Contra Costa County | — | — |
| Structure Pro | Structure Pro | — | (925) 366 8086 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Stryk Construction | Russell Patrick Stryker | — | (415) 309 8520 | GC, remodel, ADU | Lafayette · Contra Costa County | — | — |
| Stuart Construction | Stuart Duncan Littell | — | (510) 653 1615 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| Stuart Construction | James Michael Stuart | — | (510) 590 1269 | GC, remodel, ADU | El Cerrito · Contra Costa County | — | — |
| Stuart Cutt | Stuart Cutt | — | (925) 864 9224 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Stuart Englehart Construction | Stuart Benton Englehart | — | (925) 944 4984 | GC, remodel, ADU | Pleasant Hill · Contra Costa County | — | — |
| Stuart Thomas Love DBA Eastshore Plumbing | Eastshore Plumbing | — | (520) 724 2743 | Other | Pinole · Contra Costa County | — | — |
| Studio Crit Construction INC | William Terrence Plunkett | — | (510) 258 9636 | GC, remodel, ADU | Orinda · Contra Costa County | — | — |
| Style & Structure INC | Liron Rozen | — | (800) 875 2820 | GC, remodel, ADU | Pleasant Hill · Contra Costa County | — | — |
| Style Builders Construction LLC | Kenneth Daniel Clark | — | (925) 285 6750 | GC, remodel, ADU | Pleasant Hill · Contra Costa County | — | — |
| Success Water Systems INC | Robert Lee Kinslow | info@successwatersystems.com | (925) 513 2373 | Other | Brentwood · Contra Costa County | — | — |
| Sudweeks Excavating | Wayne David Sudweeks | — | (925) 525 9905 | Other | Brentwood · Contra Costa County | — | — |
| Suite Additions | Suite Additions | — | (925) 858 3946 | Electricians | Concord · Contra Costa County | — | — |
| Suliafu Construction | Suliafu Lausii Naufahu | — | (650) 282 0039 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |
| Sullivan Brother Plumber INC | Nathan Andrew Sullivan | — | (925) 323 4159 | Other | Concord · Contra Costa County | — | — |
| Sullivan Construction Company INC | Jerry Patrick Sullivan | — | (925) 689 2177 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Sulvaran Drywall | Sulvaran Drywall | tomas@sulvarandrywallca.com | (925) 384 6785 | Other | Antioch · Contra Costa County | — | — |
| Sumerlin Painting | Sumerlin Painting | — | (925) 984 8105 | Windows, patio, painters | Concord · Contra Costa County | — | — |
| Sumi Builders | Zhuoyuan Li | — | (494) 579 0299 | GC, remodel, ADU | San Ramon · Contra Costa County | — | — |
| Sumi Construction INC | Li Zhuoyuan | — | (949) 579 0299 | GC, remodel, ADU | San Ramon · Contra Costa County | — | — |
| Summerhill Construction Company | Braden Michael Stephenson | — | (925) 244 7500 | GC, remodel, ADU | San Ramon · Contra Costa County | — | — |
| Summit Construction | Tsogtkhuu Purevdorj | — | (415) 678 7121 | GC, remodel, ADU | Lafayette · Contra Costa County | — | — |
| Summit Height Construction Inc. | Christian Samuel Diaz Machuca | hugh@summitheight.com | (925) 550 2312 | GC, remodel, ADU | Oakley · Contra Costa County | — | — |
| Summit Landscape INC | Jorge Hernandez Martinez | — | (925) 229 4779 | Windows, patio, painters | Martinez · Contra Costa County | — | — |
| Sun Development & Construction INC | Majid Payandeh Azad | — | (510) 599 6229 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Sun Francis Painting | Sun Francis Painting | — | (510) 691 2060 | Windows, patio, painters | San Pablo · Contra Costa County | — | — |
| Sun Pirates INC | Robert William Edw Davey | — | (209) 769 6411 | Electricians | Danville · Contra Costa County | — | — |