| A-z Plumbing INC | Vladimir Reese | — | (925) 399 7779 | Other | Oakley · Contra Costa County | — | — |
| A. Ortiz Landscaping Corporation | Adolfo Ortiz | — | (925) 529 5843 | Windows, patio, painters | Oakley · Contra Costa County | — | — |
| A1 Bay Area Painters INC | Santhosh Kumar Reddy Kanjula | — | (925) 389 1722 | Windows, patio, painters | San Ramon · Contra Costa County | — | — |
| A1 Home Roofing | Fariborz Ghorban | — | (800) 450 7165 | Other roofers | Orinda · Contra Costa County | — | — |
| A1 Painting | A1 Painting | a1painting2004@yahoo.com | (925) 956 3744 | Windows, patio, painters | Martinez · Contra Costa County | — | — |
| A1 Phoenix Plumbing INC | James Ray Warford | info@a1phoenixplumbing.com | (925) 380 1114 | GC, remodel, ADU | Pittsburg · Contra Costa County | — | — |
| A1 Quality Contractor INC | Deshawn Khiry Garcia | a1qualitycontractor.inc@gmail.com | (925) 508 8381 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |
| A1 Quality Refinishing | A1 Quality Refinishing | info@a1qualityrefinishing.com | (925) 798 1144 | Other | Danville · Contra Costa County | — | — |
| A2 Remodeling | A2 Remodeling | — | (510) 367 4761 | GC, remodel, ADU | Rodeo · Contra Costa County | — | — |
| A2z Construction Co | Ungsoh Bruce Choi | pmarlow@a2zconstruction.com | (925) 726 7722 | GC, remodel, ADU | Martinez · Contra Costa County | — | — |
| A2z Hvacr | A2z Hvacr | — | (925) 550 5719 | HVAC | Concord · Contra Costa County | — | — |
| A2z Restoration | Shibam Afik | hello@rfuenzalida.com | (415) 323 9358 | GC, remodel, ADU | Martinez · Contra Costa County | — | — |
| A3 Pro West | A3 Pro West | impallari@gmail.com | (805) 888 7194 | Other roofers | Brentwood · Contra Costa County | — | — |
| A3 Smart Home LP DBA Aaa Smart Home | Lance Allen Chapman | — | (925) 840 4777 | Electricians | Walnut Creek · Contra Costa County | — | — |
| A4 Builders LLC | Justin Claude Allen | — | (530) 410 5455 | GC, remodel, ADU | Danville · Contra Costa County | — | — |
| A5 Floors INC | Jose Alfredo Palmer-gonzalez | — | (510) 472 5568 | Other | Antioch · Contra Costa County | — | — |
| Aa General Engineering | Aa General Engineering | — | (925) 250 7608 | GC, remodel, ADU | Brentwood · Contra Costa County | — | — |
| Aa Paving | Aa Paving | info@aa-paving.com | (510) 501 2601 | Other | Bay Point · Contra Costa County | — | — |
| Aaa Construction Management | Artem Vadimovich Mamekhin | — | (925) 989 1710 | GC, remodel, ADU | Clayton · Contra Costa County | — | — |
| Aaa Water Systems INC | Soltani Tony | — | (925) 686 6788 | Other | Concord · Contra Costa County | — | — |
| Aaaa Quality Garage Door Co | Ted Darren Hodges | — | (925) 625 2098 | Other | Oakley · Contra Costa County | — | — |
| Aag Construction | Achim Alois Groess | — | (925) 939 7453 | GC, remodel, ADU | Pleasant Hill · Contra Costa County | — | — |
| Aames Home Improvement | Brian Reza Ghorban | — | (925) 671 7995 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Aar General Contractor | Aar General Contractor | — | (510) 812 7815 | GC, remodel, ADU | Hercules · Contra Costa County | — | — |
| Aarnav Builders INC | Nari Pahilajrai Ramchandani | — | (510) 325 3650 | Electricians | Danville · Contra Costa County | — | — |
| Aaron Chapman Builders | Aaron Chapman Builders | — | (925) 899 7939 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Aaron Nixon Builder | Aaron Nixon Builder | — | (510) 502 0112 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| Aaronsolutions INC | Calderon Abraham | abraham@aaronsolutions.com | (510) 815 1265 | Other | Richmond · Contra Costa County | — | — |
| Ab Construction | Angel Luis Barros | — | (925) 325 1700 | Electricians | Brentwood · Contra Costa County | — | — |
| Ab Construction INC | Andrew Lawrence Boggeri | — | (925) 708 2491 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Ab Framing Company INC | Alvarez Omar Becerra | — | (925) 421 8380 | Other | Pittsburg · Contra Costa County | — | — |
| Abacus Concrete | Abacus Concrete | ep@abacusconcrete.com | (925) 667 8734 | Other | Brentwood · Contra Costa County | — | — |
| Abba Stone And Tile INC | Armando Barajas | — | (415) 648 2501 | Other | San Pablo · Contra Costa County | — | — |
| Abbes Construction | Ronald Christopher Jr Abbes | ron@abbesconstruction.com | (925) 570 4630 | GC, remodel, ADU | Danville · Contra Costa County | — | — |
| Abc Construction | Makeev Alex | — | (510) 455 1806 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Abenoja Floors | Abenoja Floors | — | (925) 752 2629 | Other | Oakley · Contra Costa County | — | — |
| Able Garage Door Repair Instalation | Able Garage Door Repair Instalation | — | (408) 306 2209 | Other | Brentwood · Contra Costa County | — | — |
| Able T Construction Company | Tan Genxiang | — | (415) 602 3604 | GC, remodel, ADU | Brentwood · Contra Costa County | — | — |
| Above & Beyond Construction And Remodeling | Justin Joseph Hourany | — | (925) 808 8711 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Above And Beyond Roofing And Tear Off Services | Johanny Elvira Howard | — | (510) 599 8916 | Other roofers | El Cerrito · Contra Costa County | — | — |