| Working For You Construction | Jesse Drury Working | — | (707) 685 3412 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Worsham Pump Co | Victor Manuel Velasquez | — | (707) 448 5904 | Other | Vacaville · Solano County | — | — |
| Wp Collins Construction | William Peter Collins | — | (415) 706 1462 | GC, remodel, ADU | Fairfield · Solano County | — | — |
| Wpcs International - Suisun City INC | Brandon Michael Ripley | — | (707) 421 1300 | Other | Fairfield · Solano County | — | — |
| Wsc INC DBA Western Sign Co | Kyle Rudolf Urban | — | (707) 422 6011 | Other | Fairfield · Solano County | — | — |
| Xfinity Painting INC | Jaime Becerra | — | (510) 460 2112 | Windows, patio, painters | Vallejo · Solano County | — | — |
| Xkt Engineering INC | Gary Vernon Mathison | — | (707) 562 2500 | GC, remodel, ADU | Vallejo · Solano County | — | — |
| Yantas Complete Landscaping | Yantas Complete Landscaping | — | (707) 430 8429 | Windows, patio, painters | Dixon · Solano County | — | — |
| Yeakley Construction | Matthew Brian Yeakley | — | (707) 386 6898 | GC, remodel, ADU | Suisun City · Solano County | — | — |
| Yelton Company INC | Charles Wray Yelton | firstname@yelton.com | (707) 451 3366 | Other | Vacaville · Solano County | — | — |
| Your Garage Door Guys | Your Garage Door Guys | — | (805) 955-0340 | Other | Vallejo · Solano County | — | — |
| Yugo Electric | Daniel Robert Yugo | — | (707) 880 9044 | Electricians | Vacaville · Solano County | — | — |
| Yupana INC | Muzaffer Mete Dalan | — | (925) 482 0657 | Electricians | Benicia · Solano County | — | — |
| Z And T Construction Limited Liability Company | Travis Leon Thomsen | — | (707) 529 3476 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Zehr Building And Fabrication | Zehr Building And Fabrication | — | (404) 668 7657 | GC, remodel, ADU | Vallejo · Solano County | — | — |
| Zepco Construction | Roberto Antonio Zepeda | — | (707) 712 4152 | GC, remodel, ADU | Vallejo · Solano County | — | — |
| Zepeda Custom Painting INC | Ernesto Mora Zepeda | — | (925) 787 2358 | Windows, patio, painters | Benicia · Solano County | — | — |
| Zoe Landscaping INC DBA Zoe General Construction | Timothy Jacob Klyberg | — | (707) 628 1974 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Zoological Fabrication | Zoological Fabrication | — | (916) 454 3414 | GC, remodel, ADU | Vallejo · Solano County | — | — |
| Zuvich Precision Painting | Zuvich Precision Painting | — | (707) 718 9179 | Windows, patio, painters | Vacaville · Solano County | — | — |