| Swiers Electrical Services | Bryan Andrew Swiers | — | (209) 278 8067 | Electricians | Concord · Contra Costa County | — | — |
| Swift Certified Mechanical | Swift Certified Mechanical | — | (925) 827 5561 | HVAC | Concord · Contra Costa County | — | — |
| Swift Restoration INC | Michael Beserman | — | (415) 713 4426 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Swinerton / Webcor Jv | Builders Swinerton | — | (925) 602 6400 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Swinerton Builders | Genaro Iii Nuno | — | (925) 602 6400 | Other roofers | Concord · Contra Costa County | — | — |
| Swinerton Builders & Power Engineering A Joint Venture | Engineering Construction Company Power | — | (925) 602 6400 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Swinerton Energy INC | Aaron Matthew Townsend | information@swinertonenergy.com | (925) 602 6400 | Other | Concord · Contra Costa County | — | — |
| Swinerton Management & Consulting LLC | Kevin Kala Kaanehe | — | (925) 602 6400 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Swinerton Rubecon Joint Venture | Builders Swinerton | — | (925) 602 6400 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Switch Plug Electric | Julio Cesar Ramirez | — | (925) 826 8715 | Electricians | Concord · Contra Costa County | — | — |
| Sycamore Electric LLC | Matthew Scott Edson | — | (925) 856 6004 | Electricians | Danville · Contra Costa County | — | — |
| Sycamore Valley Landscape LLC | Scott Emil O'drobinak | — | (925) 719 6856 | Windows, patio, painters | Alamo · Contra Costa County | — | — |
| Symbolic Plumbing | Waheed Tamim Popal | — | (510) 396 9233 | Other | San Ramon · Contra Costa County | — | — |
| Symbolic Remodeling And Construction | Waheed Tamim Popal | — | (510) 396 9233 | GC, remodel, ADU | San Ramon · Contra Costa County | — | — |
| Symplify Roofing INC | Eitan Yitzchak Perlman | — | (844) 796 5439 | Other roofers | Walnut Creek · Contra Costa County | — | — |
| Synergy Construction Co | Gregory Paul Schulz | — | (925) 299 8888 | GC, remodel, ADU | Lafayette · Contra Costa County | — | — |
| Synergyplus LLC | Alberto Daniel-Camargo | — | (415) 244 3503 | HVAC | Pinole · Contra Costa County | — | — |
| Systematic Electric | Gonzalez Bernardo | — | (925) 219 6053 | Electricians | Pittsburg · Contra Costa County | — | — |
| T & C Construction | Timothy John Mc Connell | — | (925) 256 9064 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| T & C Plumbing And Rooter INC | Edwin Esau Calderon | — | (925) 812 5381 | Other | Pittsburg · Contra Costa County | — | — |
| T & C Roofing INC DBA Town & Country Roofing | Jeffery Joseph Tamayo | — | (925) 634 7663 | Other roofers | Brentwood · Contra Costa County | — | — |
| T & D Contracting Services | Timothy Dean Day | — | (925) 595 5400 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| T & J Carmona INC DBA Cool Breeze | Timothy Gabriel Carmona | — | (408) 422 2021 | HVAC | Brentwood · Contra Costa County | — | — |
| T & T Landscaping & Maintenance | Thuong Tran | — | (415) 797 2236 | Windows, patio, painters | San Pablo · Contra Costa County | — | — |
| T & T Painting Co | Steven Randall Thaw | — | (925) 376 3380 | Windows, patio, painters | Moraga · Contra Costa County | — | — |
| T - 1 Electric INC | Anthony Alan Jr Himan | — | (408) 648 7321 | Electricians | Concord · Contra Costa County | — | — |
| T A S K | T A S K | — | (925) 855 3205 | Other | San Ramon · Contra Costa County | — | — |
| T B Plumbing | Tommy Andrew Balistreri | inquiries@tbplumbing.com | (925) 370 1195 | Other | Martinez · Contra Costa County | — | — |
| T Bubniak | T Bubniak | — | (925) 325 9456 | GC, remodel, ADU | Discovery Bay · Contra Costa County | — | — |
| T Callanta Enterprises | Anthony Victor Callanta | — | (925) 595 0827 | GC, remodel, ADU | Clayton · Contra Costa County | — | — |
| T D Construction | Michael Robert Curtis | — | (510) 612 6330 | GC, remodel, ADU | Brentwood · Contra Costa County | — | — |
| T D K Construction | Keith Elliot Kastner | — | (925) 588 1949 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| T E P S | Kenneth Wayne Williams | — | (925) 681 2238 | HVAC | Concord · Contra Costa County | — | — |
| T G B Service Contractor | Thomas George Bailey | — | (925) 323 7851 | Electricians | Concord · Contra Costa County | — | — |
| T G Floor Covering | T G Floor Covering | — | (925) 360 1572 | Other | Concord · Contra Costa County | — | — |
| T G Hardwood Floors | T G Hardwood Floors | — | (925) 376 1118 | Other | Moraga · Contra Costa County | — | — |
| T Hubbard Electric | Therron Austin Hubbard | — | (925) 567 6971 | Electricians | Oakley · Contra Costa County | — | — |
| T I M E House Construction | Juan Antonio Mejia Rodriguez | — | (415) 272 1597 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| T J Carpet | T J Carpet | — | (510) 385 4823 | Other | Brentwood · Contra Costa County | — | — |
| T J General Construction | Huy Quang Le | — | (510) 375 3454 | GC, remodel, ADU | Hercules · Contra Costa County | — | — |