| Yv Elite Construction LLC | Kamen Georgiev Georgiev | yveliteconstructioninc@gmail.com | (925) 639 8655 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Z & W Floors | Gregory John Walker | — | (925) 726 8394 | Other | Pittsburg · Contra Costa County | — | — |
| Z L C Corp | Tisza Arianna Lori Shastid | — | (925) 465 6663 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Z M Electric 925 INC | Mikerevic Zoran | — | (925) 250 6495 | Electricians | Pleasant Hill · Contra Costa County | — | — |
| Z M I Stone INC | Rabinder Singh Madahar | — | (510) 254 3722 | Other | Concord · Contra Costa County | — | — |
| Z Mazza Masonry | Z Mazza Masonry | — | (925) 290 6992 | Other | Concord · Contra Costa County | — | — |
| Z N Keas Painting INC | Zachary Neal Keas | — | (925) 550 0990 | Windows, patio, painters | Oakley · Contra Costa County | — | — |
| Z O B Builders | Z O B Builders | — | (510) 453 4675 | GC, remodel, ADU | San Pablo · Contra Costa County | — | — |
| Z Yang Heating & Cooling | Z Yang Heating & Cooling | — | (626) 558 1260 | HVAC | Richmond · Contra Costa County | — | — |
| Zacan INC | Hector Gabriel Ortiz | — | (510) 589 3626 | GC, remodel, ADU | San Pablo · Contra Costa County | — | — |
| Zacarias Remodeling Construction INC | Oscar Delfino Zacarias Lopez | info@zacariasremodelingconstruction.com | (510) 472 8193 | GC, remodel, ADU | Pittsburg · Contra Costa County | — | — |
| Zach Giberson | Zach Giberson | — | (831) 588 7668 | GC, remodel, ADU | Brentwood · Contra Costa County | — | — |
| Zach White Construction | Zachary Dale White | — | (925) 487 6773 | GC, remodel, ADU | Danville · Contra Costa County | — | — |
| Zak Tile & Stone | Zak Tile & Stone | — | (619) 540 2607 | GC, remodel, ADU | Martinez · Contra Costa County | — | — |
| Zaldana Construction | Guillermo Antonio Zaldana | zaldana.construction@hotmail.com | (510) 200 4245 | GC, remodel, ADU | Pittsburg · Contra Costa County | — | — |
| Zamora Mastercraft Construction | Ted Louis Dickinson | — | (925) 270 5999 | GC, remodel, ADU | Oakley · Contra Costa County | — | — |
| Zamora's Painting | Zamora's Painting | — | (925) 270 5999 | Windows, patio, painters | Oakley · Contra Costa County | — | — |
| Zanger Construction | Joshua Thomas Alpho Zanger | — | (831) 673 0632 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Zankco Renovations INC | Mark Anthony Zankich | — | (925) 349 4229 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Zapa Construction INC | Yama Kashifi | — | (310) 754 5217 | GC, remodel, ADU | San Ramon · Contra Costa County | — | — |
| Zapp Electric | Kalani Jude Sweeney | — | (925) 240 9277 | Electricians | Oakley · Contra Costa County | — | — |
| Zarate Structural Steel Works | Zarate Structural Steel Works | — | (510) 205 8521 | Other | Richmond · Contra Costa County | — | — |
| Zarcoli Professional Painting INC | Arturo Fajardo Zarco | — | (925) 628 4787 | Windows, patio, painters | Antioch · Contra Costa County | — | — |
| Zavala Brothers Construction INC | Herrera Andres Zavala | — | (925) 584 7527 | GC, remodel, ADU | Oakley · Contra Costa County | — | — |
| Zavala Tile | Zavala Tile | — | (510) 776 2506 | Other | Richmond · Contra Costa County | — | — |
| Zebra Construction | Robert Allen Collins | info@zebra-construction.com | (510) 858 8818 | GC, remodel, ADU | San Pablo · Contra Costa County | — | — |
| Zecenas Construction | Zecena Rigoberto | — | (415) 726 0716 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Zech Mechanical | Zech Mechanical | — | (415) 233 1823 | Electricians | Richmond · Contra Costa County | — | — |
| Zeidan Painting & Decorating | Zeidan Painting & Decorating | — | (510) 548 4499 | Windows, patio, painters | Moraga · Contra Costa County | — | — |
| Zembucando | Dean Shinichi Fukawa | — | (510) 684 8323 | GC, remodel, ADU | Hercules · Contra Costa County | — | — |
| Zen Construction | Dmitriy Igorevich Doronkin | — | (925) 708 1587 | GC, remodel, ADU | Pleasant Hill · Contra Costa County | — | — |
| Zermeno's Painting | Zermeno's Painting | — | (510) 846 8705 | Windows, patio, painters | Richmond · Contra Costa County | — | — |
| Zero Waste Energy @ Davis Street An Urbaser Project LLC | Eric Drake Herbert | — | (925) 378 7875 | Other | Walnut Creek · Contra Costa County | — | — |
| Zeus Design Build INC | Rozay Jesse | — | (510) 390 1245 | GC, remodel, ADU | Canyon · Contra Costa County | — | — |
| Zf Heating & Cooling | Zf Heating & Cooling | — | (415) 818 6993 | HVAC | Concord · Contra Costa County | — | — |
| Zigenis Painting | Zigenis Painting | — | (510) 333 2257 | Windows, patio, painters | Orinda · Contra Costa County | — | — |
| Zinhul Construction | Alieksieienko Ievgenii | — | (415) 307 6246 | GC, remodel, ADU | Hercules · Contra Costa County | — | — |
| Zmi Landscape Co | Zackery Myhan Innocenti | — | (925) 260 0142 | Windows, patio, painters | Lafayette · Contra Costa County | — | — |
| Zovich Construction | Zovich Ante | — | (925) 775 4227 | GC, remodel, ADU | Brentwood · Contra Costa County | — | — |
| Zviad Zaqariadze | Zviad Zaqariadze | — | (415) 786 7450 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |