| Women's Plumbing Repair | Women's Plumbing Repair | — | (510) 593 3038 | Other | Oakland · Alameda County | — | — |
| Wonderlin Roofing Systems INC | Grover Bernard Wonderlin | — | (510) 538 1530 | Other roofers | Castro Valley · Alameda County | — | — |
| Wong Plumbing | Wong Plumbing | — | (510) 559 3925 | Other | Castro Valley · Alameda County | — | — |
| Wong S Construction Co | Wong Wei Shen | — | (510) 828 7948 | GC, remodel, ADU | San Leandro · Alameda County | — | — |
| Wood Pecker Concrete | Eduardo Sr Miranda | — | (510) 798 5923 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| Woodberry Development Company | Kris Woodbury Yapp | — | (510) 538 8448 | GC, remodel, ADU | Castro Valley · Alameda County | — | — |
| Woodcraft Installations INC | Alexandra Claire Chambers | %20alex@woodcraftinstallations.com | (510) 909 9492 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| Woodpecker Remodeling And Construction | Martin Perez Pedro | — | (510) 978 0601 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| Woodruff Design & Construction INC | Martin B Woodruff | — | (408) 438 7534 | GC, remodel, ADU | Pleasanton · Alameda County | — | — |
| Woodsum Construction INC | Daniel Lee Woodsum | — | (510) 376 1030 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| Woodworking By Motown Creations | Woodworking By Motown Creations | — | (650) 759 6796 | Other | Hayward · Alameda County | — | — |
| Woodworks Construction & Design INC | Peter Russell Kyle | — | (510) 704 0966 | GC, remodel, ADU | Berkeley · Alameda County | — | — |
| Wopan Wu Construction Co | Wu Wopan | — | (415) 629 6155 | GC, remodel, ADU | Dublin · Alameda County | — | — |
| Working Willows | Varun Gupta | — | (703) 489 2514 | Windows, patio, painters | Pleasanton · Alameda County | — | — |
| Workshop Construction | Trevor Warren Stafford | — | (510) 463 7748 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| World Exteriors INC | Christopher Anthony Coelho | proteam@mopro.com | (925) 215 4515 | Other roofers | Livermore · Alameda County | — | — |
| World Flooring | World Flooring | — | (415) 786 5935 | Other | Hayward · Alameda County | — | — |
| World Pro Painting INC | Raiff Freire De Q Mendes | contact@worldpropainting.com | (510) 203 5904 | Windows, patio, painters | Fremont · Alameda County | — | — |
| Worldwide Electrical Signs | Robert Allen Kocik | — | (925) 447 7446 | Other | Livermore · Alameda County | — | — |
| Worldwide Restoration & Construction INC | Steven C Berman | — | (248) 996 3595 | GC, remodel, ADU | Dublin · Alameda County | — | — |
| Wright Brothers Builders INC | Rene Calderon | — | (650) 630 0664 | GC, remodel, ADU | Fremont · Alameda County | — | — |
| Wright Mead INC | Heidi Laurent Mead | — | (510) 907 0156 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| Wright S Miller | Wright S Miller | eben@eyebytes.com | (510) 520 3777 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| Wu Construction | Brian Mark Wu | — | (510) 501 5365 | GC, remodel, ADU | Castro Valley · Alameda County | — | — |
| Wu's Construction INC | Wei Hua Wu | — | (510) 501 2005 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| Wy Construction | Wang Yanting | — | (650) 334 8017 | GC, remodel, ADU | Fremont · Alameda County | — | — |
| X L Construction | Liang Xiaodong | info@xlconstruction.com | (510) 830 6281 | GC, remodel, ADU | San Leandro · Alameda County | — | — |
| X5 Networks LLC | Michael Wayne Jr Mcleod | — | (510) 846 8035 | Other | Union City · Alameda County | — | — |
| Xg Building Services | Xiu Guang Liu | — | (510) 303 6882 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| Xian Da Song | Xian Da Song | — | (408) 718 9555 | GC, remodel, ADU | Newark · Alameda County | — | — |
| Xiaomi Construction INC | Yanqing Chen | — | (202) 765 8673 | GC, remodel, ADU | Union City · Alameda County | — | — |
| Xicay Electric INC | Luis Enrique Xicay Ejcalon | info@xicayelectric.com | (510) 688 3813 | Electricians | Fremont · Alameda County | — | — |
| Xotek INC | Antonio Hyun Kim | — | (510) 538 1987 | GC, remodel, ADU | Castro Valley · Alameda County | — | — |
| Xt General Construction Co | Canaan Gan Ten Xin | — | (415) 724 9173 | GC, remodel, ADU | San Leandro · Alameda County | — | — |
| Xtreme 1 Electric Contractor | Luis Fernando Arriola Cortez | — | (510) 467 6097 | Electricians | San Leandro · Alameda County | — | — |
| Y & Z Construction | Zhao Yuhang | — | (510) 332 6661 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| Y B B Construction INC | Leila F Bouhedda | — | (510) 472 2679 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| Y I Develop INC DBA Lifestyle Developers INC | Itzhak Isaac Yadgar | — | (206) 802 4553 | GC, remodel, ADU | Hayward · Alameda County | — | — |
| Y O Build LLC | Yvette Maria Ortiz | — | (650) 468 6447 | GC, remodel, ADU | Oakland · Alameda County | — | — |
| Y&l Construction And Remodeling | Weiqu Zhu | — | (510) 387 3883 | GC, remodel, ADU | San Leandro · Alameda County | — | — |