| Amex Building Solutions INC | Porfirio Rubio | — | (925) 708 3192 | GC, remodel, ADU | Brentwood · Contra Costa County | — | — |
| Amezcua Construction INC | Hernandez Eleazar Amezcua | — | (925) 586 8982 | GC, remodel, ADU | Pittsburg · Contra Costa County | — | — |
| Amg Custom Builders | Michael Joseph Gutridge | — | (975) 783 0501 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |
| Amg Excavating INC | Anthony Edward Guaimano | — | (925) 570 4630 | GC, remodel, ADU | Danville · Contra Costa County | — | — |
| Amg Painting | Amg Painting | — | (650) 531-0727 | Windows, patio, painters | Antioch · Contra Costa County | — | — |
| Amg Quality Plumbing And Rooter | Amg Quality Plumbing And Rooter | — | (925) 261 6121 | Other | Antioch · Contra Costa County | — | — |
| Aml Construction INC | Lopez Alonso | — | (510) 734 7053 | GC, remodel, ADU | Pinole · Contra Costa County | — | — |
| Ammar Electric | Ammar Yaseen Hasan Aldoori | — | (510) 472 0919 | Electricians | Concord · Contra Costa County | — | — |
| Amn Homes | Amn Homes | — | (510) 480 7073 | GC, remodel, ADU | Pinole · Contra Costa County | — | — |
| Amn Plumbing INC | Anthony Michael Nicoli | — | (510) 375 3127 | Other | San Pablo · Contra Costa County | — | — |
| Amores Mechanical INC | Shawn Robert Amores | — | (415) 938 0808 | HVAC | Knightsen · Contra Costa County | — | — |
| Amores Plumbing Company | Robert Owens Amores | — | (415) 823 4432 | Other | Danville · Contra Costa County | — | — |
| Amp Electric | Eric Troy Goodbar | — | (510) 253 3049 | Electricians | Rodeo · Contra Costa County | — | — |
| Amp It Up Electric INC | Jeffrey William Lapat | — | (925) 360 0785 | Electricians | Concord · Contra Costa County | — | — |
| Amped Up Electric | Zachary Allen Wells | — | (925) 550 6720 | Electricians | Concord · Contra Costa County | — | — |
| Ampko Heating And Air Conditioning | Ampko Heating And Air Conditioning | — | (925) 687 1409 | HVAC | Concord · Contra Costa County | — | — |
| Ams Construction LLC | Michael Edward Hannig | — | (925) 487 8261 | GC, remodel, ADU | Brentwood · Contra Costa County | — | — |
| Amw Construction And Development INC | Adam Mark Wetzel | — | (925) 542 9482 | GC, remodel, ADU | Oakley · Contra Costa County | — | — |
| Anatoli Electric | Anatoli Tzviatkiv Pavlov | — | (408) 930 0953 | Electricians | Concord · Contra Costa County | — | — |
| Anaya Tile Stone INC | Rafael Anaya | — | (510) 235 1530 | Other | San Pablo · Contra Costa County | — | — |
| Anchor Door | Anchor Door | sales@anchordoor.com | (925) 370 9750 | Other | Martinez · Contra Costa County | — | — |
| Anchor Heating & Cooling INC | Eric Wayne Miller | — | (510) 520 9157 | HVAC | Pleasant Hill · Contra Costa County | — | — |
| Anchored Floors LLC | Brandon Lee Datuin | — | (925) 514 9500 | Other | Concord · Contra Costa County | — | — |
| Anco Construction Company | Jason W L Yung | — | (925) 381 1484 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |
| Ancof Construction & Remodeling | Carlos Fernando Oliva | — | (510) 734 7872 | GC, remodel, ADU | Pinole · Contra Costa County | — | — |
| Anderson Construction | Michael Joseph Anderson | — | (925) 998 7200 | GC, remodel, ADU | Clayton · Contra Costa County | — | — |
| Anderson Home Solutions INC | Richard Scott Anderson | — | (925) 595 0855 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Andiamo Plumbing | Andiamo Plumbing | — | (925) 876 1699 | Other | Walnut Creek · Contra Costa County | — | — |
| Andino Builders And Development INC | Victor Alfonso Medina Garcia | — | (925) 956 3557 | GC, remodel, ADU | Bay Point · Contra Costa County | — | — |
| Andino Construction | Gerson Ariel Andino Cerrato | — | (415) 410 1129 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| Andrade Link Electric Corporation | Adolfo Andrade-Medal | linkelectriccorp@gmail.com | (415) 305 7646 | Electricians | Richmond · Contra Costa County | — | — |
| Andre's Mechanical And General Engineering INC | Andrzej Boleslaw Fiutek | — | (925) 323 1871 | Other | Antioch · Contra Costa County | — | — |
| Andres Design Woodwork INC | Castaneda Rodriguez Andres | — | (510) 224 1312 | Other | San Pablo · Contra Costa County | — | — |
| Andrew Antonov Tile | Andrew Antonov Tile | — | (415) 225 8161 | Other | Richmond · Contra Costa County | — | — |
| Andrew Lee | Andrew Lee | — | (415) 531 3131 | Other | Richmond · Contra Costa County | — | — |
| Andrew Mathias | Andrew Mathias | — | (925) 667 6309 | GC, remodel, ADU | Oakley · Contra Costa County | — | — |
| Andrew Reams Painting | Andrew Reams Painting | — | (925) 586 4351 | Windows, patio, painters | Concord · Contra Costa County | — | — |
| Andrew Thomas Roy | Andrew Thomas Roy | — | (925) 285 9041 | Other | Danville · Contra Costa County | — | — |
| Andrew Trias | Andrew Trias | — | (510) 719 0834 | GC, remodel, ADU | Martinez · Contra Costa County | — | — |
| Andrey Chosenko Construction | Andrey Vasilyevich Chosenko | — | (925) 639 0620 | GC, remodel, ADU | Danville · Contra Costa County | — | — |