| Conco | Karen Ann Watson | — | (925) 685 6799 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Conco Pumping | Steven Alan Gonsalves | — | (925) 685 6799 | Other | Concord · Contra Costa County | — | — |
| Conco Services LLC | Brian John Drago | — | (800) 345 3476 | Other | Antioch · Contra Costa County | — | — |
| Concord Ca Roofing & Commercial Roof Repair | Concord Ca Roofing & Commercial Roof Repair | — | (408) 438-5134 | Other roofers | Concord · Contra Costa County | — | — |
| Concord Carpet And Hardwood INC | Tyler Donald Lau | — | (925) 691 7100 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Concord Cement | Concord Cement | — | (925) 787 3617 | Other | Walnut Creek · Contra Costa County | — | — |
| Concord Drywall INC | Timothy Ray Titsworth | — | (925) 676 9255 | Other | Concord · Contra Costa County | — | — |
| Concord Glass INC | Ronald Govan | concordglass@gmail.com | (925) 777 9191 | Windows, patio, painters | Concord · Contra Costa County | — | — |
| Concord Iron Works INC | Jill Marie Lee | — | (925) 432 0136 | Other | Pittsburg · Contra Costa County | — | — |
| Concord Locksmith And Safes | Oleg Alex Berger | — | (925) 689 1534 | Other | Concord · Contra Costa County | — | — |
| Concord Plumbing Co INC | Marco Antonio Becerra | concordplumbing@hotmail.com | (925) 334 6066 | Other | Concord · Contra Costa County | — | — |
| Concord Roofing | Concord Roofing | — | (925) 966-1640 | Other roofers | Concord · Contra Costa County | — | — |
| Concrete Construction | Jose Marcio Castro Reis | — | (650) 271 6059 | Other | Oakley · Contra Costa County | — | — |
| Concrete Paver Restorations LLC DBA Concrete Paver Restorations | Andrew Lyn Bogetti | — | (408) 828 6903 | Restoration | Walnut Creek · Contra Costa County | — | — |
| Concrete Visions INC | Rodger Nicholas Iglesias | — | (925) 634 1033 | Other | Brentwood · Contra Costa County | — | — |
| Concretum Operis INC | Odilon Nemesio Gonzalez | concretum721@yahoo.com | (415) 729 6060 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| Conetec INC | Clayton John Bartholomew | info@conetec.com | (510) 357 3677 | Other | Richmond · Contra Costa County | — | — |
| Connect | Carl James Henderson | support@youspot.com | (925) 336 4757 | Other | Brentwood · Contra Costa County | — | — |
| Connect Tek Of California INC | Jason Wayne Lehrer | — | (925) 634 8475 | Electricians | Brentwood · Contra Costa County | — | — |
| Connerstone | Conners Jay | — | (510) 672 4493 | Other | Richmond · Contra Costa County | — | — |
| Connolly Heating & Air Conditioning | Ronald Norman Grimes | — | (925) 288 1408 | HVAC | Pacheco · Contra Costa County | — | — |
| Connolly Heating & Air Conditioning | Connolly Heating & Air Conditioning | — | (925) 288 1408 | HVAC | Pacheco · Contra Costa County | — | — |
| Conrad Painting & Decorating | Gary Ted Conrad | — | (925) 283 8059 | Windows, patio, painters | Lafayette · Contra Costa County | — | — |
| Conrado Drywall | Conrado Drywall | — | (415) 509 4485 | Other | Richmond · Contra Costa County | — | — |
| Conscious Construction INC | Sochet Jeffrey | — | (510) 450 0551 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| Considerate Contracting INC | Kevin Matthew Caro | — | (925) 457 3635 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Constable Construction | Michael Wellington Constable | — | (925) 899 7170 | GC, remodel, ADU | Moraga · Contra Costa County | — | — |
| Constanza Construction Services LLC | Michael Emanuel Constanza | constanzaconstructionservices@gmail.com | (925) 967 5598 | GC, remodel, ADU | San Ramon · Contra Costa County | — | — |
| Constellation Lighting And Electric | Martin Joseph Ortega | — | (510) 326 0696 | Electricians | El Cerrito · Contra Costa County | — | — |
| Construart Pavers Co | Gabriela De Oliveira Gonzalez | office@construartpavers.com | (650) 275 3762 | GC, remodel, ADU | El Sobrante · Contra Costa County | — | — |
| Construction By D And M INC | Jesse Emerson Fowler | — | (925) 260 8424 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |
| Construction Concepts | Mark Alan Kasche | info@constructionconcepts.com | (925) 899 2018 | GC, remodel, ADU | Pleasant Hill · Contra Costa County | — | — |
| Construction Design By United | Gregory Michael Somers | — | (925) 949 6211 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Construction H Group | H Construction INC Group | — | (510) 779 4913 | GC, remodel, ADU | San Pablo · Contra Costa County | — | — |
| Construction Network INC | David Russell Bruzzone | — | (925) 376 1921 | GC, remodel, ADU | Moraga · Contra Costa County | — | — |
| Construction Pros LLC | Shaghasi Abdullah | — | (925) 381 4486 | GC, remodel, ADU | Danville · Contra Costa County | — | — |
| Construction Remedy | Petros Firas | — | (510) 637 8973 | GC, remodel, ADU | Pinole · Contra Costa County | — | — |
| Construction Services And Remodeling | Diarmuid Joseph Drohan | — | (925) 743 9965 | GC, remodel, ADU | Danville · Contra Costa County | — | — |
| Construction Site Services INC | Ramos Avila Javier | — | (925) 305 5910 | Electricians | Pittsburg · Contra Costa County | — | — |
| Construction Specialty Service | Michael Gerard Cameron | — | (925) 519 3495 | GC, remodel, ADU | Pittsburg · Contra Costa County | — | — |