| Alpha Construction | Renteria Felipe | — | (925) 375 8013 | GC, remodel, ADU | Oakley · Contra Costa County | — | — |
| Alpha Construction Company | Pak Wing Chan | — | (415) 889 3504 | Electricians | El Cerrito · Contra Costa County | — | — |
| Alpha Design And Build INC | Christian Rafael Torres | — | (925) 557 0701 | GC, remodel, ADU | Danville · Contra Costa County | — | — |
| Alpha Eagle Roofing | Alpha Eagle Roofing | sales@alphaeagleroofing.com | (415) 410-7917 | Other roofers | San Ramon · Contra Costa County | — | — |
| Alpha Electric | David Alan Narron | — | (925) 798 8427 | Electricians | Concord · Contra Costa County | — | — |
| Alpha X Pro Remodeling | Alpha X Pro Remodeling | — | (925) 207 9445 | GC, remodel, ADU | Martinez · Contra Costa County | — | — |
| Alpha-omega Quality Painting & Decorating INC | Lyle Dean Knittel | — | (925) 634 3442 | Windows, patio, painters | Brentwood · Contra Costa County | — | — |
| Alpine Building And Remodel | Alpine Building And Remodel | — | (510) 283 3617 | GC, remodel, ADU | Rodeo · Contra Costa County | — | — |
| Alpine Diablo Construction | Peter Ross Janka | — | (707) 295 0806 | GC, remodel, ADU | Martinez · Contra Costa County | — | — |
| Alpine Heating And Air | Alpine Heating And Air | — | (214) 940 8135 | HVAC | Pittsburg · Contra Costa County | — | — |
| Als Builders Pro INC | Martinez Adolfo Soto | — | (650) 430 1811 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| Alsd Mechanical | Douglas Scott Mossholder | — | (800) 464 6866 | HVAC | Pittsburg · Contra Costa County | — | — |
| Alta American Pools INC | Ross Christopher Owens | — | (925) 766 2269 | Pool | Danville · Contra Costa County | — | — |
| Alta Fence Co | John Gordon Jones | — | (925) 777 9877 | Other | Martinez · Contra Costa County | — | — |
| Altamont Landscape Services INC | Frank William Carlson | — | (925) 634 5555 | Windows, patio, painters | Brentwood · Contra Costa County | — | — |
| Altavista Concrete | Altavista Concrete | estimates@altavistaconcrete.com | (925) 852 3740 | Other | Concord · Contra Costa County | — | — |
| Alten Construction LLC | Robert Andrew Alten | aadams@altenconstruction.com | (510) 234 4200 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| Alternative Design | Alternative Design | — | (925) 771 9098 | Electricians | Clayton · Contra Costa County | — | — |
| Althen's Enterprise | Althen's Enterprise | — | (925) 212 3455 | Windows, patio, painters | Martinez · Contra Costa County | — | — |
| Altitude Essentiel Tree Service | Dhaou Moussa | — | (415) 350 6472 | Tree | Pinole · Contra Costa County | — | — |
| Altor Construction LLC | Torabian Ali | — | (925) 639 4710 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Altos Electric INC | Guadalupe Guillermo Gonzalez | — | (510) 335 6410 | Electricians | San Pablo · Contra Costa County | — | — |
| Alvarado & Son Construction INC | Jose Isabel Alvarado-salinas | — | (510) 776 4557 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| Alvarado Masonry | Alvarado Masonry | — | (925) 864 6406 | Other | Oakley · Contra Costa County | — | — |
| Alvarado Tree Service | Alvarado Benites Leodegario | — | (510) 672 7853 | Tree | Richmond · Contra Costa County | — | — |
| Alvarado Vision Construction | Alvarado Virgilio | — | (925) 999 0045 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |
| Alvarez Landscaping And Fencing | Alvarez Landscaping And Fencing | — | (510) 799 0375 | Windows, patio, painters | Hercules · Contra Costa County | — | — |
| Alvarez Woodworks | Alvarez Woodworks | — | (510) 660 1842 | Other | Richmond · Contra Costa County | — | — |
| Alvo Landscape INC | Olaez Carrillo Alvaro | — | (925) 325 8140 | Windows, patio, painters | Oakley · Contra Costa County | — | — |
| Always Playgrounds INC | Rivera Rodriguez Oscar | — | (707) 805 9787 | Other | Bay Point · Contra Costa County | — | — |
| Always Safe Fencing | Always Safe Fencing | — | (925) 922 0385 | Other | Discovery Bay · Contra Costa County | — | — |
| Alyadoz Electric | Jose Efrain Martinez | — | (510) 621 4061 | Electricians | Richmond · Contra Costa County | — | — |
| Am Acoustics | Am Acoustics | — | (925) 451 1461 | Other | Brentwood · Contra Costa County | — | — |
| Am Construction | Andreas Richard Mccurdy | — | (925) 766 8088 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Am Construction INC | Alberto Javier Macco | — | (925) 899 1925 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Am Property Management | Am Property Management | — | (925) 216-7426 | Property managers | San Ramon · Contra Costa County | — | — |
| Amador Masonry Services INC | Torres Diego Amador | — | (510) 932 3905 | GC, remodel, ADU | San Pablo · Contra Costa County | — | — |
| Amador Painting | Amador Painting | — | (415) 574 5609 | Windows, patio, painters | San Pablo · Contra Costa County | — | — |
| Amaro's Pro Painting INC | Melchor Abraham Urbina | — | (503) 468 9633 | Windows, patio, painters | Pinole · Contra Costa County | — | — |
| Amaton Drywall INC | Gonzalo Estrada Amaton | hello@rfuenzalida.com | (925) 298 7383 | Windows, patio, painters | Walnut Creek · Contra Costa County | — | — |