| William P Jordan Construction | William Patrick Jordan | — | (925) 872 7249 | GC, remodel, ADU | Clayton · Contra Costa County | — | — |
| William R Ingham | William R Ingham | — | (925) 708 4774 | Other | Concord · Contra Costa County | — | — |
| William Sheldon Cook | William Sheldon Cook | — | (925) 963 9226 | GC, remodel, ADU | Oakley · Contra Costa County | — | — |
| Williams Electrical Systems INC | Christopher Grayson Williams | info@williamselectricalsystems.com | (510) 334 8203 | Electricians | Richmond · Contra Costa County | — | — |
| Williams Grading | Williams Grading | — | (925) 516 0572 | Other | Discovery Bay · Contra Costa County | — | — |
| Williams Sanitary Service INC | Solorio Alberto Verduzco | info@williamssanitaryservice.com | (925) 634 4855 | Other | Brentwood · Contra Costa County | — | — |
| Williamson Pools | Williamson Pools | — | (925) 497 3018 | Pool | Concord · Contra Costa County | — | — |
| Willy's Painting | Willy's Painting | — | (510) 776 0223 | Windows, patio, painters | Rodeo · Contra Costa County | — | — |
| Willy's Tree Service | William Cesar Martinez Jonda | — | (510) 710 2443 | Tree | El Cerrito · Contra Costa County | — | — |
| Willycom Communications INC | Willson Ivan Amezcua | — | (408) 835 0701 | Other | Antioch · Contra Costa County | — | — |
| Wilson Construction | Terry Clifford Wilson | — | (510) 685 3290 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| Wilson Painting | Wilson Painting | info@wilson-painting.com | (714) 720-5233 | Windows, patio, painters | Brentwood · Contra Costa County | — | — |
| Wilson Remodeling | Wilson Remodeling | — | (925) 783 0761 | GC, remodel, ADU | Pittsburg · Contra Costa County | — | — |
| Wily Figueiredo | Wily Figueiredo | — | (510) 355 5304 | Other | Pinole · Contra Costa County | — | — |
| Windham Painting INC | Keith Martin Windham | — | (209) 652 5564 | Windows, patio, painters | Discovery Bay · Contra Costa County | — | — |
| Window And Glass Pros | Window And Glass Pros | — | (925) 263 9004 | Windows, patio, painters | Concord · Contra Costa County | — | — |
| Window Innovations INC | Steven Donahue Clark | — | (925) 634 6008 | Windows, patio, painters | Brentwood · Contra Costa County | — | — |
| Window Replacement Pros | Window Replacement Pros | info@replacementwindowsmartinez.com | (925) 886-6119 | Windows, patio, painters | Martinez · Contra Costa County | — | — |
| Window Station INC | Leonid Elbert | — | (415) 235 4143 | Windows, patio, painters | Concord · Contra Costa County | — | — |
| Windows 4 U | Elbert Leonid | — | (925) 595 1453 | Windows, patio, painters | Walnut Creek · Contra Costa County | — | — |
| Windows Doors & More | Windows Doors & More | — | (510) 384 0805 | GC, remodel, ADU | San Pablo · Contra Costa County | — | — |
| Windsor Pacific Property Management | Windsor Pacific Property Management | — | (925) 248-5030 | Property managers | San Ramon · Contra Costa County | — | — |
| Wing Construction Co | Wing Fai Chan | — | (925) 487 4797 | GC, remodel, ADU | San Ramon · Contra Costa County | — | — |
| Wingard Construction INC | Bror David Wingard | — | (925) 689 9322 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Winzeler Construction | Joshua Christopher Winzeler | — | (510) 485 2555 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| Wirthman Property Group LLC | Grant James Wirthman | — | (925) 899 4726 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Wise Builders INC | Eun Gyu Kim | — | (925) 407 7092 | GC, remodel, ADU | Pleasant Hill · Contra Costa County | — | — |
| Wise Construction | Kenneth William Robinson | — | (925) 586 3207 | GC, remodel, ADU | Byron · Contra Costa County | — | — |
| Wmg Enterprises INC | Luis Morales | — | (415) 368 4339 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| Woehrle And Son Builders | Woehrle And Son Builders | — | (925) 212 8771 | GC, remodel, ADU | Lafayette · Contra Costa County | — | — |
| Wolf Renovations | Tariq Eric Aslami | — | (925) 655 9653 | GC, remodel, ADU | Pleasant Hill · Contra Costa County | — | — |
| Wolf's Intuitive Landscapes | Wolf's Intuitive Landscapes | — | (925) 825 5090 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Wolpert & Associates | Jeremy Raymond Wolpert | — | (949) 838 7535 | GC, remodel, ADU | San Ramon · Contra Costa County | — | — |
| Wood Trix Construction INC | Silva Armando Pulido | — | (925) 698 4180 | GC, remodel, ADU | Bay Point · Contra Costa County | — | — |
| Wood's Construction | Herbert Bannister Wood | — | (925) 431 0620 | GC, remodel, ADU | Pittsburg · Contra Costa County | — | — |
| Woodbridge Construction | Morales Oscar Vega | — | (415) 377 7765 | GC, remodel, ADU | Point Richmond · Contra Costa County | — | — |
| Woodchuck Tree Care | Woodchuck Tree Care | — | (925) 849 4056 | Tree | Pleasant Hill · Contra Costa County | — | — |
| Wooden' It Be Nice | Wooden' It Be Nice | — | (925) 285 9922 | Other | Clayton · Contra Costa County | — | — |
| Woodiwiss Painting LLC | Toby Luke Woodiwiss | — | (925) 788 5263 | Windows, patio, painters | Pleasant Hill · Contra Costa County | — | — |
| Woodman Hardwood Floors | Woodman Hardwood Floors | info@woodmanhardwoodfloors.com | (510) 965 5051 | Other | Richmond · Contra Costa County | — | — |