| Torres Builders LLC | Jaime Ceja | micah@micahrich.com | (707) 671 3394 | GC, remodel, ADU | Clearlake · Lake County | — | — |
| Torrigino Flooring | Torrigino Flooring | — | (707) 262 2047 | Other | Lucerne · Lake County | — | — |
| Totorica Plumbing INC | Frank Michael Totorica | — | (707) 279 4020 | Other | Kelseyville · Lake County | — | — |
| Totorica Tile Co | Mark Alan Totorica | — | (707) 279 2045 | Other | Kelseyville · Lake County | — | — |
| Traction King LLC | Dennis Loyd Brooner | — | (707) 500 5018 | Other | Upper Lake · Lake County | — | — |
| Trinity Construction & Land Development | Barry Roger Fullman | — | (707) 530 1555 | GC, remodel, ADU | Kelseyville · Lake County | — | — |
| Trinity Roofing Arrowhead | Trinity Roofing Arrowhead | — | (442) 233-3491 | Other roofers | Lake Arrowhead · Lake County | — | — |
| Trison Builders | Dare Jacob Green | — | (707) 802 8787 | GC, remodel, ADU | Clearlake · Lake County | — | — |
| Troy Carrillo Concrete INC | Troy Cedric Carrillo | — | (707) 295 7615 | Other | Middletown · Lake County | — | — |
| Trusolution Pest Control & Rodent Management | Trusolution Pest Control & Rodent Management | — | (916) 865-6946 | Pest, tile roofs | Plumas Lake · Lake County | — | — |
| Tsr Excavating | Kody Robert Hubert | tsrexcavating@gmail.com | (707) 495 8885 | Other | Lower Lake · Lake County | — | — |
| Turner European Construction | Laszlo Istuan Turner | — | (707) 987 3985 | GC, remodel, ADU | Hidden Valley Lake · Lake County | — | — |
| Turner Insulation Company | Mark Louis Borghesani | — | (707) 279 1800 | Other | Kelseyville · Lake County | — | — |
| Underdog Painting | Underdog Painting | gerard@underdogpainting.com | (707) 367 5781 | Windows, patio, painters | Lakeport · Lake County | — | — |
| Uribe Landscapes | Uribe Landscapes | — | (707) 530 4032 | Windows, patio, painters | Cobb · Lake County | — | — |
| Vantage Construction INC | James Michael Watson | — | (707) 360 7346 | GC, remodel, ADU | Cobb · Lake County | — | — |
| Vg Construction | Valverde-guzman Rogelio | — | (714) 936 5837 | GC, remodel, ADU | Lower Lake · Lake County | — | — |
| Webb Land Development | Webb Land Development | — | (707) 472 7353 | Other | Clear Lake · Lake County | — | — |
| Well Hung Garage Doors | Well Hung Garage Doors | — | (707) 830 0207 | Other | Hidden Valley Lake · Lake County | — | — |
| Wes Walls | Wes Walls | weswallsmusic@gmail.com | (707) 295 7077 | GC, remodel, ADU | Kelseyville · Lake County | — | — |
| West Coast | Douglas Keith Bridges | — | (707) 462 5326 | GC, remodel, ADU | Kelseyville · Lake County | — | — |
| West Coast Painter | West Coast Painter | — | (707) 320 8876 | Windows, patio, painters | Clearlake · Lake County | — | — |
| West Coast Roofing Services | Nicholas James Martin | — | (707) 799 1644 | Other roofers | Hidden Valley Lake · Lake County | — | — |
| Western General Engineering | Western General Engineering | — | (707) 972 4381 | Other | Kelseyville · Lake County | — | — |
| Westlake Environmental Contractors | Keith Alan Westlake | — | (707) 291 9115 | GC, remodel, ADU | Lakeport · Lake County | — | — |
| Weston Construction | Michael David Weston | — | (707) 396 3987 | GC, remodel, ADU | Kelseyville · Lake County | — | — |
| Wheelan Engineering | Wheelan Engineering | — | (707) 349 5900 | Tree | Kelseyville · Lake County | — | — |
| Wilder Construction | Jeffery Curtis Wilder | — | (707) 318 5422 | GC, remodel, ADU | Cobb · Lake County | — | — |
| Will Peterson Well Drilling | Will Peterson Well Drilling | william.peterson707@yahoo.com | (707) 277 0103 | Other | Kelseyville · Lake County | — | — |
| William Clark | William Clark | — | (707) 972 8895 | GC, remodel, ADU | Kelseyville · Lake County | — | — |
| William R Bero | William R Bero | — | (707) 987 8508 | GC, remodel, ADU | Hidden Valley Lake · Lake County | — | — |
| Willy And Son Construction | Gary David Wilcox | — | (707) 349 2167 | GC, remodel, ADU | Lakeport · Lake County | — | — |
| Willy's Construction | Gary David Wilcox | — | (707) 349 2167 | GC, remodel, ADU | Lakeport · Lake County | — | — |
| Window World Of San Diego | Window World Of San Diego | — | (760) 645-8948 | Windows, patio, painters | San Marcos · Lake County | — | — |
| Wiser Plumbing INC | Kelly Lee Wiser | — | (707) 533 9496 | Other | Kelseyville · Lake County | — | — |
| Witzel Construction | Evan Roy Witzel | — | (707) 987 2685 | Other | Middletown · Lake County | — | — |
| Woodall Construction | David Allen Woodall | — | (415) 994 6869 | GC, remodel, ADU | Kelseyville · Lake County | — | — |
| Woodbine Contractors | Alfred J Young | — | (707) 495 1169 | Other | Middletown · Lake County | — | — |
| Yanez Roofing | Yanez Javier | — | (707) 263 3265 | Other roofers | Lakeport · Lake County | — | — |
| Young & Family INC | Hilary Cecil Young | — | (707) 263 8877 | GC, remodel, ADU | Lakeport · Lake County | — | — |