| Western Asset Recovery INC | George Joseph Rose | — | (209) 848 8095 | GC, remodel, ADU | Oakdale · Stanislaus County | — | — |
| Western Building & Remodeling | Western Building & Remodeling | — | (209) 404 4588 | GC, remodel, ADU | Modesto · Stanislaus County | — | — |
| Western Doors & Windows INC | Kevin Mark Shatswell | — | (209) 568 8306 | Other | Salida · Stanislaus County | — | — |
| Western Fence Company | Lance Richard Harvey | — | (209) 456 3705 | GC, remodel, ADU | Oakdale · Stanislaus County | — | — |
| Western Flooring INC | Duane Gregory Johnson | colt@western-flooring.com | (858) 560 5557 | Other | Modesto · Stanislaus County | — | — |
| Western Metal Buildings | John C Shatswell | info@westernmetalbuildings.com | (209) 543 9361 | GC, remodel, ADU | Oakdale · Stanislaus County | — | — |
| Western Mining Services LLC | Michael Clayton Loche | — | (209) 521 1410 | Other | Ceres · Stanislaus County | — | — |
| Western Plumbing Corporation | Daniel Melvin Sibley | — | (209) 848 8629 | Other | Oakdale · Stanislaus County | — | — |
| Western Sand & Water Blasting Co | Michael Angel Orozco | — | (209) 582 5677 | Other | Modesto · Stanislaus County | — | — |
| Western Slipform | Western Slipform | — | (209) 470 9782 | Other | Oakdale · Stanislaus County | — | — |
| Westside Landscape & Concrete INC | Armando Estrada Garcia | — | (209) 862 3908 | GC, remodel, ADU | Newman · Stanislaus County | — | — |
| Westside Paint & Stain | Westside Paint & Stain | — | (209) 985 2904 | Windows, patio, painters | Newman · Stanislaus County | — | — |
| Weststar Fire Systems INC | Alfred Alvarado | — | (209) 579 5199 | Other | Modesto · Stanislaus County | — | — |
| Wheeler Irrigation Repair LLC | Lane Oland Wheeler | — | (209) 620 6770 | Other | Turlock · Stanislaus County | — | — |
| White Construction | Loren Edward White | — | (209) 499 3049 | GC, remodel, ADU | Modesto · Stanislaus County | — | — |
| Whorton Construction | Dennis Dewain Whorton | — | (209) 605 6226 | GC, remodel, ADU | Modesto · Stanislaus County | — | — |
| Wiggins Fencing | Wiggins Fencing | — | (209) 985 5056 | Other | Modesto · Stanislaus County | — | — |
| Wiley's Custom Fabrication & Design | Wiley's Custom Fabrication & Design | — | (209) 844 5275 | Other | Oakdale · Stanislaus County | — | — |
| Wilfredo's Garage Door INC | Wilfredo Aguirre | wilfredosinstaller@gmail.com | (209) 492 0111 | Other | Modesto · Stanislaus County | — | — |
| Wilfredo's Garage Door Installer | Wilfredo's Garage Door Installer | — | (209) 492 0111 | Other | Modesto · Stanislaus County | — | — |
| Wilkey Industries INC | Patricia Ann Wilkey | — | (209) 656 0561 | HVAC | Turlock · Stanislaus County | — | — |
| William Cook Plumbing & Construction Incorporated | William Ted Iii Cook | — | (925) 980 2141 | GC, remodel, ADU | Patterson · Stanislaus County | — | — |
| William Rucker Painting | William Rucker Painting | — | (209) 345 6311 | Windows, patio, painters | Oakdale · Stanislaus County | — | — |
| Williams Construction Company | Daniel William Vidal | — | (408) 595 8907 | GC, remodel, ADU | Riverbank · Stanislaus County | — | — |
| Williams Heat & Air | Williams Heat & Air | — | (209) 537 8151 | HVAC | Modesto · Stanislaus County | — | — |
| Willow Landscape | Willow Landscape | — | (209) 521 4980 | Windows, patio, painters | Modesto · Stanislaus County | — | — |
| Wilson Family Plumbing INC | Donald Joseph Wilson | — | (209) 874 2555 | Other | Waterford · Stanislaus County | — | — |
| Wilson Portable Welding | Wilson Portable Welding | — | (209) 765 3596 | Other | Denair · Stanislaus County | — | — |
| Wilson Technologies | Brian Allan Self | — | (209) 577 2240 | Other | Modesto · Stanislaus County | — | — |
| Windward Pacific Builders INC | Randal Blinn Hurlburt | — | (209) 521 0803 | GC, remodel, ADU | Modesto · Stanislaus County | — | — |
| Windy Tree INC | Wendy Erin Quinn | — | (209) 499 0219 | Tree | Oakdale · Stanislaus County | — | — |
| Winma Heating & Air INC | Winston Appiah | — | (209) 857 6073 | HVAC | Modesto · Stanislaus County | — | — |
| Winters Ranch Electric | Robert Randolph Winters | — | (209) 613 1637 | Electricians | Newman · Stanislaus County | — | — |
| Wire Guys Group INC | Rimond Karim | — | (209) 765 9300 | Electricians | Turlock · Stanislaus County | — | — |
| Wittmers Electric INC | Kathryn Marie Wittmers | — | (405) 687 0580 | Electricians | Oakdale · Stanislaus County | — | — |
| Wlf Construction INC | Villalobos Valentine | — | (209) 552 1112 | GC, remodel, ADU | Oakdale · Stanislaus County | — | — |
| Wolfpack Earthcare & Irrigation INC | Jakob Javan Magana | — | (209) 505 8863 | Windows, patio, painters | Modesto · Stanislaus County | — | — |
| Womack Striping INC | Cynthia Catherine Womack | — | (209) 550 0771 | Other | Modesto · Stanislaus County | — | — |
| Wood Connection INC | Upma Agarwala | — | (209) 248 6103 | Other | Modesto · Stanislaus County | — | — |
| Wood Dreams Construction Specialities | Roderick Lee Cascia | — | (209) 573 1682 | GC, remodel, ADU | Denair · Stanislaus County | — | — |