| The Wall Artist | The Wall Artist | — | (925) 413 9383 | Windows, patio, painters | Walnut Creek · Contra Costa County | — | — |
| The Workaholics | James Francis Boice | — | (510) 758 9675 | GC, remodel, ADU | San Pablo · Contra Costa County | — | — |
| The Workshop Co | Or Palmor | — | (925) 412 4135 | GC, remodel, ADU | Clayton · Contra Costa County | — | — |
| Thermo H V A C Refrigeration | Joe Duy Nguyen | — | (925) 405 2590 | HVAC | Concord · Contra Costa County | — | — |
| Thiel Carpentry And Construction Corporation | Jacob Alexander Thiel | — | (510) 915 3362 | GC, remodel, ADU | El Sobrante · Contra Costa County | — | — |
| Thomas Albert Seeno | Thomas Albert Seeno | — | (925) 932 4655 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Thomas Black General Contractor | Thomas Black General Contractor | — | (925) 286 5941 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Thomas Builders | Thomas Builders | — | (925) 200 9302 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Thomas C Bergesen Const | Thomas C Bergesen Const | — | (925) 260 9671 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Thomas Cunniff Construction | Thomas Michael Cunniff | — | (415) 378 2007 | GC, remodel, ADU | Kensington · Contra Costa County | — | — |
| Thomas Ward Construction INC | Thomas Matthew Ward | — | (925) 277 1000 | GC, remodel, ADU | Danville · Contra Costa County | — | — |
| Thomas William Young | Thomas William Young | — | (510) 296 2012 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Thomas-swan Sign Company INC | Bruce Emerson Thomas | — | (510) 232 9610 | Other | Richmond · Contra Costa County | — | — |
| Thor Contracting Corporation | Alexander Anthony Montano | mail@thorconstructionco.com | (415) 837 3496 | Other roofers | El Sobrante · Contra Costa County | — | — |
| Thor Trevor Conrad | Thor Trevor Conrad | — | (925) 354 0569 | Other | Pleasant Hill · Contra Costa County | — | — |
| Thorn Construction | William R Thorn | — | (925) 283 4949 | GC, remodel, ADU | Lafayette · Contra Costa County | — | — |
| Thorpe Design INC | Corey Russell Lee Gray | — | (925) 634 5758 | Electricians | Brentwood · Contra Costa County | — | — |
| Thousand Oaks Painting Co | Roland Madrid De La Torre | — | (510) 525 1960 | Windows, patio, painters | El Sobrante · Contra Costa County | — | — |
| Three Lights Electric INC | Joel Eduardo Morales Guerra | joelmorales@threelightselectric.com | (631) 830 2254 | Electricians | Oakley · Contra Costa County | — | — |
| Three Moon Construction | John Tandoc Munoz | — | (510) 213 0333 | GC, remodel, ADU | Hercules · Contra Costa County | — | — |
| Thuan Landscape & Gardening Service | Thuan Van Tran | — | (510) 872 4154 | GC, remodel, ADU | Pinole · Contra Costa County | — | — |
| Thunder Legacy Builders INC | Hernandez Omar Romero | info@thunderlegacybuilders.com | (925) 848 0716 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Thunder Yak Electric LLC | Tenzin Jinpa | — | (510) 804 1174 | Electricians | Richmond · Contra Costa County | — | — |
| Tice Valley Electric INC | Luis Kim Altwer | — | (925) 954 5500 | Electricians | Concord · Contra Costa County | — | — |
| Tidal Marine Construction INC | Shawn Eugene Stambaugh | — | (925) 609 6464 | Other | Antioch · Contra Costa County | — | — |
| Tide Wave Pools INC | Lucas De Carvalho Lea Silva | — | (510) 990 1808 | Pool | Pittsburg · Contra Costa County | — | — |
| Tier 1 Construction | Anthony Ray Grover | — | (925) 852 7200 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Tier 1 Plumbing | Tier 1 Plumbing | — | (925) 316 5893 | Other | Pacheco · Contra Costa County | — | — |
| Tight Lines Painting | Tight Lines Painting | — | (530) 913 2249 | Windows, patio, painters | Martinez · Contra Costa County | — | — |
| Tikal Construction | Vidal Adelso Morales | admin@tikalconstruction.com | (415) 652 3681 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| Tile And Stone Plus Flooring | Tile And Stone Plus Flooring | — | (925) 207 1684 | Other | Discovery Bay · Contra Costa County | — | — |
| Tile Artist | Tile Artist | — | (925) 639 7114 | Other | Concord · Contra Costa County | — | — |
| Tile By Design | Tile By Design | — | (510) 862 3167 | Other | Walnut Creek · Contra Costa County | — | — |
| Tile Creationz | Tile Creationz | — | (925) 207 5145 | Other | Martinez · Contra Costa County | — | — |
| Tile Details INC | Coto Edwin Guzman | — | (415) 368 2708 | Other | San Pablo · Contra Costa County | — | — |
| Tile Floors Counters & Showers By Randy | Randy Russell Pfohl | — | (925) 864 1594 | Other | Pleasant Hill · Contra Costa County | — | — |
| Tim Cosetti | Tim Cosetti | — | (925) 594 2010 | GC, remodel, ADU | Alamo · Contra Costa County | — | — |
| Tim Dennis Construction | Timothy Allen Dennis | — | (925) 788 6019 | GC, remodel, ADU | Martinez · Contra Costa County | — | — |
| Tim Height | Tim Height | — | (510) 967 8963 | Other | San Pablo · Contra Costa County | — | — |
| Tim Lawlor Construction | Timothy Sean Lawlor | tim@timlawlorconstruction.com | (925) 387 8947 | GC, remodel, ADU | Concord · Contra Costa County | — | — |