| Andrzej The Painter Co | Andrzej Stan Kielak | — | (925) 207 3432 | Windows, patio, painters | San Ramon · Contra Costa County | — | — |
| Andrzej Wincenty Baran | Andrzej Wincenty Baran | — | (415) 760 1460 | Other | Richmond · Contra Costa County | — | — |
| Andy Byrne Construction | Andrew George Byrne | — | (415) 350 0513 | GC, remodel, ADU | Hercules · Contra Costa County | — | — |
| Aneceto Mendoza | Aneceto Mendoza | — | (925) 307 4009 | GC, remodel, ADU | San Ramon · Contra Costa County | — | — |
| Angel Electric | Mario Valencia Galvan | — | (650) 245 7584 | Electricians | San Pablo · Contra Costa County | — | — |
| Angel's Construction | Hernandez Angel | — | (415) 810 5049 | GC, remodel, ADU | Pittsburg · Contra Costa County | — | — |
| Angeles Plastering INC | Angeles Ordonez Hugo | — | (415) 297 9615 | Other | San Pablo · Contra Costa County | — | — |
| Angelic Construction | Vincent Angelo Williams | — | (510) 332 2592 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Aniv Construction | Dmitri Anisimov | — | (925) 515 5050 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Anlos Remodeling Services INC | Carlos Jesus Altamirano Rodriguez | — | (925) 658 8527 | GC, remodel, ADU | Pittsburg · Contra Costa County | — | — |
| Anro INC | Rostyslav Sagadyn | — | (415) 948 9618 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Anstirman Construction INC | Roberto Armando Anstirman | — | (415) 678 9085 | GC, remodel, ADU | Martinez · Contra Costa County | — | — |
| Anthony Allen Calif | Anthony Allen Calif | — | (510) 703 0848 | Other | San Ramon · Contra Costa County | — | — |
| Anthony B Kohler Construction Company | Anthony Blaine Kohler | — | (925) 625 1244 | GC, remodel, ADU | Oakley · Contra Costa County | — | — |
| Antioch Plumbing | Bret Jay Nissen | — | (925) 766 7449 | Other | Oakley · Contra Costa County | — | — |
| Antonio Ducharme | Antonio Ducharme | — | (925) 354 9894 | Other | Brentwood · Contra Costa County | — | — |
| Any Angle Construction | Albert Melvin Iii Olson | — | (925) 250 8070 | GC, remodel, ADU | Brentwood · Contra Costa County | — | — |
| Anytime Glass LLC | Amenouche Hakim | — | (510) 682 1969 | Windows, patio, painters | Oakley · Contra Costa County | — | — |
| Anza Builders | Neema Mohammadizad | info@anzabuilders.com | (925) 900 3170 | GC, remodel, ADU | Alamo · Contra Costa County | — | — |
| Anza Engineering Corp | Loni Jean Radetic | — | (925) 513 2060 | GC, remodel, ADU | Brentwood · Contra Costa County | — | — |
| Ao Energy Solutions INC | Kip Allen Trombley | accounting@aoenergysolutions.com | (925) 285 5118 | Electricians | Bay Point · Contra Costa County | — | — |
| Ap & Deck Waterproofing Systems | Ap & Deck Waterproofing Systems | — | (925) 686 2761 | Windows, patio, painters | Concord · Contra Costa County | — | — |
| Ap Custom Builds LLC | Sadique Popal | — | (925) 808 9751 | GC, remodel, ADU | Danville · Contra Costa County | — | — |
| Apartment Renovation Specialists INC | Joseph Matthew Mendelsohn | — | (925) 689 2177 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Apb General Engineering | Alfred Kah Chun Lee | — | (925) 989 1453 | Other | San Pablo · Contra Costa County | — | — |
| Apc Lath And Plaster | Apc Lath And Plaster | — | (925) 329 1680 | Other | Oakley · Contra Costa County | — | — |
| Apco Paving Company | Avila Jesse | — | (925) 827 9850 | Other | Concord · Contra Costa County | — | — |
| Apex Air | Gerald Albert Davis | — | (925) 457 7478 | HVAC | Walnut Creek · Contra Costa County | — | — |
| Apex Commercial Coatings INC | Robert David Serkiz | — | (925) 382 4165 | Windows, patio, painters | Discovery Bay · Contra Costa County | — | — |
| Apex Countertops INC | Jorge Quintero Gutierrez | — | (925) 665 4752 | Other | Bay Point · Contra Costa County | — | — |
| Apex Development Global | Long Tuan On | — | (408) 547 7736 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Apex General Construction And Renovations | Dylan Joseph Maia | — | (510) 685 0640 | GC, remodel, ADU | Martinez · Contra Costa County | — | — |
| Apex Grading INC | Marcus Jason Fifield | — | (825) 818 7075 | Other | Concord · Contra Costa County | — | — |
| Apex Home Improvement And Remodeling | Apex Home Improvement And Remodeling | — | (415) 324 9307 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Apex Pavers Specialists INC | Itamar Leite Jr De Morais | — | (510) 343 4405 | Other | Pinole · Contra Costa County | — | — |
| Apex Refrigeration Corporation | Lewis Marvin Lehner | — | (510) 653 9850 | HVAC | Concord · Contra Costa County | — | — |
| Apex Remodeling Bay Area INC | Michael Gordon Moxley | — | (347) 422 3270 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Aplus Plumbing | Aplus Plumbing | — | (510) 453 7667 | Other | San Ramon · Contra Costa County | — | — |
| Apm Mechanical Heating & Air | Apm Mechanical Heating & Air | — | (916) 470 7856 | HVAC | Concord · Contra Costa County | — | — |
| Apodaca Mechanical | Marc Albert Apodaca | — | (925) 673 8987 | HVAC | Clayton · Contra Costa County | — | — |