| Acorn Landscaping INC | Andrew Landes Packer | — | (510) 915 3720 | Windows, patio, painters | Orinda · Contra Costa County | — | — |
| Acorym Developers | Michael Lawrence Williams | — | (510) 866 6375 | GC, remodel, ADU | Pinole · Contra Costa County | — | — |
| Acosta Builders | Acosta Builders | luis@acosta-builders.com | (401) 688-6533 | GC, remodel, ADU | Pinole · Contra Costa County | — | — |
| Acosta Landscaping | Acosta Landscaping | acostalawncare@gmail.com | (925) 752 6507 | Windows, patio, painters | Concord · Contra Costa County | — | — |
| Activate Fire Protection | Kyle Robert Williams | help@activatefireprotection.com | (925) 848-0188 | Other | Brentwood · Contra Costa County | — | — |
| Acustruct | Daniel William Yust | — | (925) 872 4680 | Electricians | Concord · Contra Costa County | — | — |
| Acw Steel | Acw Steel | — | (415) 861 8410 | Other | Richmond · Contra Costa County | — | — |
| Adajar Construction | Primo Gutierrez Jr Adajar | — | (925) 575 1500 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Adam Gonzales LLC | Gonzales Adam | — | (559) 812 8487 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Adam Lawrence Howard Construction | Lawrence Keith Howard | — | (510) 691 1425 | GC, remodel, ADU | Rodeo · Contra Costa County | — | — |
| Adam M Arrington Construction & Design | Adam Michael Arrington | — | (510) 759 8036 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Adam Wilbanks Construction | Adam Christian Wilbanks | — | (925) 785 9061 | GC, remodel, ADU | Danville · Contra Costa County | — | — |
| Adama Construction | Ana Isabel Gutierrez | — | (510) 220 7311 | GC, remodel, ADU | Pinole · Contra Costa County | — | — |
| Adan Flores General Contractor | Adan Flores General Contractor | — | (650) 766 0716 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| Adan's Painting Services | Adan De Jesus Munoz Enriquez | — | (510) 487 8249 | Windows, patio, painters | Richmond · Contra Costa County | — | — |
| Addison Communications LLC | Steve Earl Vanmeetren | — | (925) 453 1747 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |
| Adg Development & Investments INC | John Edward Hyjer | — | (925) 708 8994 | GC, remodel, ADU | Orinda · Contra Costa County | — | — |
| Adh Construction LLC | Andrew Durham Harnett | — | (510) 409 3338 | GC, remodel, ADU | Orinda · Contra Costa County | — | — |
| Adls Builders Corp | Mendoza Liliana Orozco | — | (510) 992 9375 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |
| Adriano Dos Santos | Adriano Dos Santos | — | (510) 253 7142 | Other | San Pablo · Contra Costa County | — | — |
| Adriatic Builders LLC | Obradovic Dejan | — | (510) 332 1377 | Electricians | Hercules · Contra Costa County | — | — |
| Adu Crew LLC | Brian Christopher O'leary | — | (925) 979 5450 | GC, remodel, ADU | Clayton · Contra Costa County | — | — |
| Adval Construction INC | Alan Richard Stubbs | — | (925) 324 4438 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Advance Construction And Development INC | William J Eppinga | — | (925) 864 0985 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Advance Design Builder | Advance Design Builder | — | (818) 795 1674 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Advance Design Construction INC | Frederick Marshall Lamb | — | (925) 323 4175 | GC, remodel, ADU | Brentwood · Contra Costa County | — | — |
| Advance Pool Care INC | Michael Allan Schaezler | info@advancepoolcare.com | (925) 309 4685 | Pool | Danville · Contra Costa County | — | — |
| Advance Telecom INC | Marco Antonio Rodriguez | — | (510) 921 1149 | Other | Brentwood · Contra Costa County | — | — |
| Advanced Automatic Sprinkler INC | Frederick Joseph Iii Benn | — | (925) 552 5870 | Other | San Ramon · Contra Costa County | — | — |
| Advanced Construction | Afsarifard Farshad | interested@domainmarket.com | (415) 377 8048 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Advanced Control | Advanced Control | info@advancedcontrol.com | (208) 362-5858 | HVAC | Orinda · Contra Costa County | — | — |
| Advanced Elevator Solutions INC | Victor Latronica | aes@advancedelevatorsolutions.com | (510) 281 0920 | Other | Concord · Contra Costa County | — | — |
| Advanced Equipment Services | Stephen Joseph Rivas | — | (925) 945 7411 | HVAC | Pacheco · Contra Costa County | — | — |
| Advanced Office Systems INC | David Eric Hatfield | — | (925) 687 3100 | Other | Concord · Contra Costa County | — | — |
| Advanced Pipeline Services | Robert James Whitman | — | (209) 815 3822 | Other | Oakley · Contra Costa County | — | — |
| Advanced Plumbing & Drain Master | Advanced Plumbing & Drain Master | — | (925) 732 3351 | Other | Brentwood · Contra Costa County | — | — |
| Advanced Plumbing And Rooter Service | William Niel Van Mastrigt | — | (925) 383 6100 | Other | San Ramon · Contra Costa County | — | — |
| Advanced T I INC | Joseph Allen Standridge | — | (925) 299 0515 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Advanced Trenchless INC | Ryan Matthew Charles | — | (925) 932 4023 | GC, remodel, ADU | Martinez · Contra Costa County | — | — |
| Advanced Voice & Data INC | Scott Alan Levine | — | (925) 681 2800 | Other | Concord · Contra Costa County | — | — |