| Turn Key Builders | Turn Key Builders | — | (707) 249 5969 | Electricians | Martinez · Contra Costa County | — | — |
| Turner / Devcon A Joint Venture | Construction Company Turner | — | (650) 228 6945 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Turner Design & Construction | Benjamin Arnold James Turner | — | (510) 798 7374 | GC, remodel, ADU | El Sobrante · Contra Costa County | — | — |
| Tuscano Plumbing Service And Drain | Brian Alexander Tuscano | — | (510) 478 3462 | Other | Concord · Contra Costa County | — | — |
| Tutino Construction | David Nicholas Tutino | — | (925) 285 7726 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Tutt's Truck Outfitters INC | John Franklin Iv Tuttle | — | (831) 254 1735 | Other | Pittsburg · Contra Costa County | — | — |
| Twin Flames Services HVAC & Title 24 Duct Testing | Luis Omar Ramirez Garibay | — | (925) 239 8665 | HVAC | Bay Point · Contra Costa County | — | — |
| Twin Pines Plumbing | Twin Pines Plumbing | — | (925) 269 4850 | Other | Oakley · Contra Costa County | — | — |
| Twinwood Development INC | Mike Chi-Cheng Lin | — | (510) 251 1115 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Two Bricks Design Build | Two Bricks Design Build | — | (925) 785 0706 | GC, remodel, ADU | San Ramon · Contra Costa County | — | — |
| Two Ton Construction | Kevin Khoa Tan Nguyen | — | (408) 204 8400 | GC, remodel, ADU | El Cerrito · Contra Costa County | — | — |
| Tws Fine Wood Windows INC | Darryll Lyman Butterfield | — | (510) 865 9663 | Windows, patio, painters | Concord · Contra Costa County | — | — |
| Tyler J Palmer - General Contractor | Palmer Taylor J- General Contractor | — | (925) 759 7045 | GC, remodel, ADU | Orinda · Contra Costa County | — | — |
| Tyndall HVAC INC | Peter Michael Tyndall | service@tyndallhvac.com | (925) 998 9909 | HVAC | Antioch · Contra Costa County | — | — |
| Tyren Construction | Richard Kenneth Tyren | — | (925) 250 2777 | GC, remodel, ADU | Diablo · Contra Costa County | — | — |
| U C I Construction INC | Jeffrey Russell Holz | — | (925) 370 9808 | Other | Concord · Contra Costa County | — | — |
| U S Electric | Nicholas Austin Vargas | — | (925) 642 9245 | Electricians | Discovery Bay · Contra Costa County | — | — |
| U S Electric Controls INC | Nicholas Austin Vargas | — | (925) 642 9245 | Electricians | Discovery Bay · Contra Costa County | — | — |
| U S Glass & Aluminum INC Which Will Do Business In California As | John Patrick Brimmer | — | (925) 427 7100 | Windows, patio, painters | Pittsburg · Contra Costa County | — | — |
| U S Plumbing & Rooter INC | Gregorio Xavier Salgado | — | (925) 238 0940 | Other | Antioch · Contra Costa County | — | — |
| U S Realty Homes INC DBA U S Realty Construction | Tommy Ho-Ming Tam | — | (408) 431 9983 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| U S T Testing Services INC | Steven Dale Sandkohl | — | (925) 288 8944 | HVAC | Concord · Contra Costa County | — | — |
| U.s. Services Gc INC | Scutelnic Ion | — | (510) 566 3885 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |
| Ua Construction | Edward Vitenberg | info@ua-construction.com | (408) 898 0113 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Ucan Builder INC | Diaz Silverio Ucan | impallari@gmail.com | (415) 299 1393 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| Ucb Builders INC | Pei-Shen Feng | ucbbuilders@gmail.com | (510) 815 9986 | GC, remodel, ADU | Pinole · Contra Costa County | — | — |
| Ufer Construction INC | Divino Ciscero Borgsr Oliveria | info@uferconstruction.com | (415) 573 8260 | GC, remodel, ADU | El Cerrito · Contra Costa County | — | — |
| Uh Services Corporation DBA Attic Green | Gal Atias | — | (510) 330 7815 | Other | Concord · Contra Costa County | — | — |
| Ulian Chinlakov | Ulian Chinlakov | — | (925) 323 4049 | Other | Concord · Contra Costa County | — | — |
| Ulloa Construction | Mario Daniel Ulloa Lopez | info@ulloa-construction.com | (714) 487-1860 | GC, remodel, ADU | El Sobrante · Contra Costa County | — | — |
| Ultimate Painting | Ultimate Painting | — | (925) 594 1801 | Windows, patio, painters | Byron · Contra Costa County | — | — |
| Ultimate Pipelines Engineering INC | Mario Jr Ornelas | — | (510) 417 8964 | Other | Hercules · Contra Costa County | — | — |
| Uma- Woodworking On Wheels | Uma- Woodworking On Wheels | — | (925) 788 8663 | Other | Walnut Creek · Contra Costa County | — | — |
| Under Construction Industries 7th Level INC | Leo John Jr Stefani | — | (925) 487 2623 | GC, remodel, ADU | Alamo · Contra Costa County | — | — |
| Undisputed Plumbers INC | Alan Santos Yanez | — | (925) 382 3068 | Other | Bay Point · Contra Costa County | — | — |
| Uni Marble INC | Andrzey Wincenty Baran | unimarble@aol.com | (510) 236 7960 | Other | Richmond · Contra Costa County | — | — |
| Uniframe Windows And Siding INC | Paula Marie Nault | — | (925) 960 0560 | Windows, patio, painters | San Ramon · Contra Costa County | — | — |
| Union Contractor Group | Robert William O'brien | — | (415) 720 5451 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| Unique Drywall | Unique Drywall | unique.contractor.drywall@gmail.com | (830) 496-2017 | Other | Oakley · Contra Costa County | — | — |
| Unique Hardwood Floor | Unique Hardwood Floor | uniquefloors@att.net | (925) 408 3956 | Other | Concord · Contra Costa County | — | — |