| Tri Star Landscape Services INC | John Anthony Zamora | — | (925) 724 9212 | Windows, patio, painters | Brentwood · Contra Costa County | — | — |
| Tri Valley Doors INC | Steve Forest Haverland | info@trivalleydoors.com | (925) 580 9125 | Other | Byron · Contra Costa County | — | — |
| Tri Valley Painting | Tri Valley Painting | — | (925) 818 4861 | Windows, patio, painters | Concord · Contra Costa County | — | — |
| Tri Valley Plumbing | Tri Valley Plumbing | — | (925) 556 5511 | Other | San Ramon · Contra Costa County | — | — |
| Tri-city Heating & Air-conditioning INC | Steve Thomas Culcasi | — | (925) 755 2665 | HVAC | Antioch · Contra Costa County | — | — |
| Tri-valley Drywall Company Incorporated | Louis Dean Salvador | — | (925) 706 2268 | Windows, patio, painters | Brentwood · Contra Costa County | — | — |
| Tri-valley Landscape Construction INC | Nancy Lee Hall | — | (925) 922 4558 | Windows, patio, painters | Brentwood · Contra Costa County | — | — |
| Tri-valley Striping | George Vaughn Deboever | info@trivalleystriping.com | (925) 787 1003 | Other | Orinda · Contra Costa County | — | — |
| Trident Environmental And Engineering INC | Michael Edward Heckathorn | — | (925) 706 6931 | Other | Brentwood · Contra Costa County | — | — |
| Trigueiro Design & Construction | Allen Joseph Trigueiro | — | (510) 816 4026 | GC, remodel, ADU | Kensington · Contra Costa County | — | — |
| Trigueros Development Group INC | Christian Jean Rousset | info@website.com | (626) 426 1654 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Trimco Construction | Peter Wayne Emery | story@trimcoconstruction.com | (925) 754 7743 | GC, remodel, ADU | Oakley · Contra Costa County | — | — |
| Trinity Electrical INC | Lindsey James Duke | — | (925) 788 7868 | Electricians | Pleasant Hill · Contra Costa County | — | — |
| Trip Hazard Landscape | Philip Aaron Rogacki | — | (800) 240 8653 | Windows, patio, painters | Bay Point · Contra Costa County | — | — |
| Triple J Construction Services | Jeffrey Frank Kolsut | — | (925) 876 5318 | GC, remodel, ADU | Lafayette · Contra Costa County | — | — |
| Triple R Electric INC | Douglas Walter Rosenberry | — | (925) 686 9140 | Electricians | Concord · Contra Costa County | — | — |
| Troels Thorenfeldt Construction Company | Kim Troels Thorenfeldt | — | (925) 932 0689 | Electricians | Lafayette · Contra Costa County | — | — |
| Tropical Construction Company | Luis Wilfredo Velez | — | (925) 778 7434 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |
| Trovec Technologies | Chris Nnamdi Chidumije | — | (510) 994 6332 | Other | Antioch · Contra Costa County | — | — |
| Troy Auzenne | Troy Auzenne | — | (925) 386 6555 | GC, remodel, ADU | Orinda · Contra Costa County | — | — |
| Troy Construction | Bas Bulent | troyconstruction10@gmail.com | (510) 528 9944 | GC, remodel, ADU | El Cerrito · Contra Costa County | — | — |
| Troy Wilson DBA Wilson Construction | Troy Anthony Wilson | — | (510) 682 7674 | GC, remodel, ADU | El Sobrante · Contra Costa County | — | — |
| True Color Painting Company | Sean Patrick Wightman | — | (925) 360 0754 | Windows, patio, painters | Oakley · Contra Costa County | — | — |
| True Craft Builders INC | Rodney Steven Pacheco | — | (925) 383 3081 | GC, remodel, ADU | Pacheco · Contra Costa County | — | — |
| True Magic Landscaping | True Magic Landscaping | — | (510) 829 6433 | Windows, patio, painters | Pinole · Contra Costa County | — | — |
| True Temp Experts | Irvin Rodrigo Argueta Nunez | — | (510) 314 9145 | HVAC | Pittsburg · Contra Costa County | — | — |
| True View Glass INC | Mamoun Basem Abdelwahhab | — | (415) 713 3999 | Windows, patio, painters | Pinole · Contra Costa County | — | — |
| True Welding LLC | Michael Glenn Mitchell | — | (707) 712 1675 | Other | Pinole · Contra Costa County | — | — |
| Trumark Construction Services INC | Anthony Tobias Bosowski | — | (925) 999 3950 | GC, remodel, ADU | San Ramon · Contra Costa County | — | — |
| Trupro Insulation | Mark Antonio Ramirez | — | (415) 286 8861 | Other | Antioch · Contra Costa County | — | — |
| Trusource Energy INC | Tony Jr Cilenti | legal@trusourceenergy.com | (925) 858 4220 | Electricians | Danville · Contra Costa County | — | — |
| Try Tile Installation LLC | Enrique Medardo Magana | — | (415) 377 1653 | Other | Richmond · Contra Costa County | — | — |
| Ts Gardencare And Landscape Services | Antonio Mafnas Salas | — | (925) 351 3801 | Windows, patio, painters | Concord · Contra Costa County | — | — |
| Tsakos Development LLC | Georgios Lampropoulos | — | (925) 785 5419 | GC, remodel, ADU | Danville · Contra Costa County | — | — |
| Tsc Metal INC | Mei Xiang | — | (415) 319 2345 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |
| Tsp Flooring INC | Anthony David Delima | — | (925) 290 7148 | GC, remodel, ADU | Brentwood · Contra Costa County | — | — |
| Tsp Roofing And Solar | Peter Justin Ellis | — | (925) 233 5013 | Other roofers | Hercules · Contra Costa County | — | — |
| Tub World | Tub World | — | (925) 798 6608 | Other | Pleasant Hill · Contra Costa County | — | — |
| Turcios General Construction | Enmanuel De Jesus Turcios Lopez | — | (925) 206 7717 | GC, remodel, ADU | Oakley · Contra Costa County | — | — |
| Turcotte Construction INC | David Allen Turcotte | — | (925) 516 9127 | GC, remodel, ADU | Byron · Contra Costa County | — | — |