| William Decker & Company INC | Rachel Marie Decker | — | (415) 850 7762 | GC, remodel, ADU | Penngrove · Sonoma County | — | — |
| William G Avellar Heating And Air Conditioning | William George Avellar | — | (707) 887 7530 | HVAC | Forestville · Sonoma County | — | — |
| William Gibson | William Gibson | — | (707) 205 7328 | GC, remodel, ADU | Rohnert Park · Sonoma County | — | — |
| William Kent Development INC | William Kent Gorton | — | (818) 345 8518 | GC, remodel, ADU | Cloverdale · Sonoma County | — | — |
| William Patrick Builders | William Patrick Builders | — | (510) 812 5515 | GC, remodel, ADU | Sonoma · Sonoma County | — | — |
| William R Bisel | William R Bisel | — | (707) 490 4134 | Other | Cotati · Sonoma County | — | — |
| William R Howell | William R Howell | — | (707) 849 0915 | Electricians | Healdsburg · Sonoma County | — | — |
| William Underwood Construction | William Arrington Underwood | — | (707) 664 9415 | GC, remodel, ADU | Cotati · Sonoma County | — | — |
| William Villa Painting | William Villa Painting | villafamily_1@msn.com | (707) 239 1676 | Windows, patio, painters | Windsor · Sonoma County | — | — |
| Williams Construction & Remodel | Pablo Lino Puentes | — | (707) 971 4741 | GC, remodel, ADU | Petaluma · Sonoma County | — | — |
| Willowglen | Benjamin Otto Vanzutphen | — | (707) 473 8620 | GC, remodel, ADU | Healdsburg · Sonoma County | — | — |
| Willy's Mobile Welding & Fabrication | Willy's Mobile Welding & Fabrication | — | (707) 322 6742 | Other | Sebastopol · Sonoma County | — | — |
| Wilo Construction Co | Ryan Michael Wilbur | — | (518) 365 4011 | GC, remodel, ADU | Petaluma · Sonoma County | — | — |
| Wilson Construction | Anthony Dean Wilson | — | (707) 568 3922 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| Wilson HVAC Solutions LLC | Luke Wilson | — | (707) 569 4404 | HVAC | Occidental · Sonoma County | — | — |
| Wilson's Locksmith & Security Center | Lawrence Duane Lindblad | — | (707) 996 3707 | Alarm and generators | Sonoma · Sonoma County | — | — |
| Wilson's Painting | Wilson's Painting | — | (530) 708 0700 | Windows, patio, painters | Santa Rosa · Sonoma County | — | — |
| Wilsons Custom Builds | Robert James Wilson | — | (760) 497 2325 | GC, remodel, ADU | Windsor · Sonoma County | — | — |
| Wind Construction | Rodriguez Lopez Gustavo | — | (707) 479 2509 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| Windsor Fabrication DBA Welding Contractor | Samuel Fred Borland | — | (707) 570 9806 | Other | Windsor · Sonoma County | — | — |
| Windsor Painting | Windsor Painting | — | (707) 695 8538 | Windows, patio, painters | Windsor · Sonoma County | — | — |
| Windsor Plumbing | Windsor Plumbing | — | (707) 535 9236 | Other | Healdsburg · Sonoma County | — | — |
| Windsor Waterproofing INC | Gerald Scott Balfour | — | (707) 703 2348 | Other | Windsor · Sonoma County | — | — |
| Windward Knolls Construction | David Eldredge Gurley | — | (415) 717 5633 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| Wine Country Builders INC | Cameron Ridge Fraser | info@winecountrybuilders.com | (707) 935 7474 | GC, remodel, ADU | Sonoma · Sonoma County | — | — |
| Wine Country Countertops LLC | Michael John Deas | — | (707) 857 4940 | Other | Santa Rosa · Sonoma County | — | — |
| Wine Country Custom Builders INC | Jeffrey Robert Cuda | — | (707) 477 6638 | GC, remodel, ADU | Sonoma · Sonoma County | — | — |
| Wine Country Electric | Richard Lindley Ii Ogg | — | (707) 477 0197 | Electricians | Bodega Bay · Sonoma County | — | — |
| Wine Country Electric Corporation | Martinez David Martinez | — | (707) 721 6770 | Electricians | El Verano · Sonoma County | — | — |
| Wine Country Fire Protection & Plumbing INC | Richard Alan Jr Hudson | — | (707) 933 7900 | Other | Sonoma · Sonoma County | — | — |
| Wine Country Flooring | Wine Country Flooring | — | (707) 280 3854 | Other | Cloverdale · Sonoma County | — | — |
| Wine Country Heating & Air Conditioning | Ryan Charles Mccown | — | (707) 536 5112 | HVAC | Windsor · Sonoma County | — | — |
| Wine Country Landscaping | Wine Country Landscaping | — | (707) 815 0557 | Windows, patio, painters | Sonoma · Sonoma County | — | — |
| Wine Country Painters INC | Lee Monte Dido | lee@winecountrypainters.com | (707) 887 8701 | Windows, patio, painters | Petaluma · Sonoma County | — | — |
| Wine Country Pools & Concrete | Wine Country Pools & Concrete | — | (707) 528 7665 | Pool | Santa Rosa · Sonoma County | — | — |
| Wine Country Remodel Corporation | Raquel Luna Pacheco | — | (707) 303 7867 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| Wine Country Roofing INC | Angel Espitia Vera | — | (707) 578 5969 | Other roofers | Santa Rosa · Sonoma County | — | — |
| Wine County Floors INC | Antonio Esparza-Vazquez | — | (707) 547 7011 | Other | Santa Rosa · Sonoma County | — | — |
| Wine County HVAC | Wine County HVAC | — | (707) 332 4148 | HVAC | Sonoma · Sonoma County | — | — |
| Wineworks Equipment & Supply | Jeffrey Thomas Allen | — | (707) 978 5843 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |