| Watersfinehomes | Watersfinehomes | — | (858) 449-3320 | GC, remodel, ADU | Carlsbad · Solano County | — | — |
| Waterwaze Innovative Plumbing Solutions | David Joseph Hanson | — | (707) 280 8866 | Other | Vallejo · Solano County | — | — |
| Watt Now INC | Sean William Zeigler | — | (707) 438 6699 | Electricians | Fairfield · Solano County | — | — |
| Watt's Up Electric INC | David Allen Stump | — | (707) 373 4054 | Electricians | Benicia · Solano County | — | — |
| Wayne Horne Plumbing | Wayne Horne Plumbing | — | (707) 647 3350 | Other | Vallejo · Solano County | — | — |
| Weber General Engineering | Weber General Engineering | — | (530) 795 1800 | Other | Vacaville · Solano County | — | — |
| Weber General Engineering INC | Bryan Morgan Weber | — | (530) 795 1800 | Other | Dixon · Solano County | — | — |
| Webster Pro Plumbing | Webster Pro Plumbing | — | (408) 384 2426 | Other | Fairfield · Solano County | — | — |
| Wedgewood Construction | Curtis Troy Wedge | — | (707) 718 6124 | GC, remodel, ADU | Fairfield · Solano County | — | — |
| Weiand And Associates Homes INC | Brent Patrick Weiand | — | (530) 308 5008 | GC, remodel, ADU | Dixon · Solano County | — | — |
| Welding Services | Brandon James Pritchard | — | (707) 330 9087 | Other | Fairfield · Solano County | — | — |
| West & Associates Environmental Engineers INC | Brian William West | — | (707) 761 2307 | Other | Vacaville · Solano County | — | — |
| West Bay General Building Contractors | Kevin Fitzgerald Domino | — | (650) 784 6216 | GC, remodel, ADU | Suisun City · Solano County | — | — |
| West Commercial And Custom Residential Builders | Paul Gerard Hansen | — | (510) 387 0966 | GC, remodel, ADU | Vallejo · Solano County | — | — |
| West Construction LLC | Alec West Brassington | — | (916) 622 3225 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| West Elm Construction | Christopher Ryan Ingram | — | (925) 330 1437 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| West Pacific Air Conditioning Heating & Cooling | David John Munoz | — | (707) 474 7200 | HVAC | Vacaville · Solano County | — | — |
| West Point Concrete INC | Reyes Jose Jesus Madrigal | — | (707) 366 4308 | Other | Suisun City · Solano County | — | — |
| West-com & Tv INC | Jonathan Richard Peters | — | (707) 428 5902 | GC, remodel, ADU | Fairfield · Solano County | — | — |
| Westec Builder | Westec Builder | — | (510) 813 3002 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Western Machinery Electric | Leonard Mark Horewitz | — | (707) 747 0125 | Electricians | Benicia · Solano County | — | — |
| Westfield Concrete | Westfield Concrete | — | (707) 419 9876 | Other | Fairfield · Solano County | — | — |
| Wetland Construction INC | Joshua Adam Knoll | — | (707) 422 6848 | Other | Suisun City · Solano County | — | — |
| Whisper Homes LLC | Peter Anthony Trapolino | — | (707) 234 5829 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Wickens Construction LLC | Bruce Neal Wickens | — | (707) 447 7475 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Wide Step Construction | Gutierrez Francisco | — | (707) 290 3663 | GC, remodel, ADU | Fairfield · Solano County | — | — |
| William Robert Walker | William Robert Walker | — | (707) 477 5444 | Other | Suisun City · Solano County | — | — |
| Williams Construction | James Mark Williams | — | (707) 428 5373 | GC, remodel, ADU | Fairfield · Solano County | — | — |
| Williams Landscaping | Williams Landscaping | — | (650) 455 2627 | Windows, patio, painters | Rio Vista · Solano County | — | — |
| Window Covering Styles | Ed Paungan Jacobe | mycover@windowcoveringstyles.com | (707) 655 5706 | Other | Vallejo · Solano County | — | — |
| Window Fashions Of Northern California INC | Kittle Misun | — | (707) 429 5156 | Other | Fairfield · Solano County | — | — |
| Windows-r-us | Timothy Austin Dalpee | — | (707) 333 8780 | Windows, patio, painters | Benicia · Solano County | — | — |
| Wink Enterprises INC | Robert Greg Wink | — | (707) 428 5509 | Electricians | Fairfield · Solano County | — | — |
| Wire-rite Electric | Barry Lee Adams | — | (707) 321 5086 | Electricians | Fairfield · Solano County | — | — |
| Wise Construction | Benitez Guerrero Ivan | — | (707) 450 6681 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Wiseman Commercial INC | Adam Wayne Goodrich | — | (707) 427 1212 | GC, remodel, ADU | Suisun City · Solano County | — | — |
| Withers Construction & Development | Alexander Marc Withers | — | (707) 685 4590 | GC, remodel, ADU | Fairfield · Solano County | — | — |
| Wohler Construction | Andrew Tobias Wohler | — | (707) 450 7178 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Wood Floored | Wood Floored | — | (530) 318 4441 | Other | Vacaville · Solano County | — | — |
| Woody J Sims | Woody J Sims | — | (707) 328 0396 | GC, remodel, ADU | Vallejo · Solano County | — | — |