| Bastion Builders | Bastion Builders | sales@bastionbuilders.com | (925) 963 9843 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Bates Builders | Bates Builders | — | (510) 401 7034 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| Bates Landscape And Hardscape | Bates Landscape And Hardscape | — | (925) 595 3059 | Windows, patio, painters | Danville · Contra Costa County | — | — |
| Bath Fixer | Bath Fixer | — | (925) 234 1982 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |
| Battaglini Electric INC | Bryan David Battaglini | wirewizzard1@outlook.com | (925) 736 2976 | Electricians | Danville · Contra Costa County | — | — |
| Battas Drywall | Battas Drywall | — | (510) 599 2856 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| Bauhaus Construction | Bazyl Sylvester Zasun | — | (510) 676 5122 | GC, remodel, ADU | Hercules · Contra Costa County | — | — |
| Bauhaus Marble & Granite | Bauhaus Marble & Granite | — | (925) 876 1201 | Other | Pittsburg · Contra Costa County | — | — |
| Bautista General Construction INC | Victor Gonzalez | — | (510) 221 1643 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| Bautista Landscaping | Bautista Landscaping | — | (510) 383 6721 | Windows, patio, painters | Concord · Contra Costa County | — | — |
| Bautista's Electric INC | Santos Alonso Bautista Aguayo | — | (925) 665 6397 | Electricians | Pittsburg · Contra Costa County | — | — |
| Bautista's Painting | Bautista's Painting | — | (510) 703 5019 | Windows, patio, painters | Oakley · Contra Costa County | — | — |
| Bay Air Flow Incorporated | Dennis Khuttan | — | (925) 852 8918 | HVAC | Pittsburg · Contra Costa County | — | — |
| Bay Air Refrigeration INC | Edwin Orlando Guerra Aguilar | bayairrefrigerationinc@yahoo.com | (510) 994 7711 | HVAC | Richmond · Contra Costa County | — | — |
| Bay Air Systems INC | Bert John Morgan | — | (925) 356 3000 | HVAC | Concord · Contra Costa County | — | — |
| Bay Alarm Company | Jonathan Robert Surridge | — | (925) 808 4315 | Electricians | Concord · Contra Costa County | — | — |
| Bay Alarm Company | Tim Bradley Westphal | bayalarm@bayalarm.com | (800) 610 1000 | Electricians | Concord · Contra Costa County | — | — |
| Bay Area Brushworks | James Michael Cook | — | (925) 326 5470 | Windows, patio, painters | Concord · Contra Costa County | — | — |
| Bay Area Builders | Scott Edward Acevedo | — | (925) 382 0630 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Bay Area Builders | Michael Anthony Lucido | — | (925) 765 3811 | GC, remodel, ADU | Brentwood · Contra Costa County | — | — |
| Bay Area Comfort HVAC INC | Ernesto Soria | bacomforthvac@gmail.com | (925) 408 9397 | HVAC | Pittsburg · Contra Costa County | — | — |
| Bay Area Comfort Solutions HVAC INC | Michael Pike Stanton | — | (510) 778 0675 | HVAC | Brentwood · Contra Costa County | — | — |
| Bay Area Construction Management Group | Derek Jeffrey Daymond | — | (510) 230 8040 | GC, remodel, ADU | Danville · Contra Costa County | — | — |
| Bay Area Contractor | Bay Area Contractor | — | (707) 690 7667 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Bay Area Custom Floors INC | Farshid Rahmani | — | (925) 727 5343 | Other | Pittsburg · Contra Costa County | — | — |
| Bay Area Doors | Bay Area Doors | — | (925) 798 3280 | Other | Concord · Contra Costa County | — | — |
| Bay Area Drainage INC | Wayne William Ortland | — | (925) 377 9209 | Windows, patio, painters | Concord · Contra Costa County | — | — |
| Bay Area Earthworks INC | Richard Christopher Knapp | — | (925) 807 8007 | Other | Concord · Contra Costa County | — | — |
| Bay Area Electric Group INC | Nissim Zanna | — | (818) 605 4085 | Electricians | Lafayette · Contra Costa County | — | — |
| Bay Area Electric LLC | Alexander Drabkin | info@bayareaelectric.com | (925) 212 0225 | Electricians | Antioch · Contra Costa County | — | — |
| Bay Area Electric Services INC | Mohammed Azzi | — | (510) 798 8455 | Electricians | Pleasant Hill · Contra Costa County | — | — |
| Bay Area Floor Experts INC | Franyer Estheban Nava Velasquez | — | (786) 312 7491 | Other | Antioch · Contra Costa County | — | — |
| Bay Area Floor Services | Phuc Kham Le | — | (408) 531 5046 | Other | Antioch · Contra Costa County | — | — |
| Bay Area General Construction | Juan Carlos Sanchez Bustos | — | (925) 671 0465 | GC, remodel, ADU | Bay Point · Contra Costa County | — | — |
| Bay Area Greenscapes INC | Wayne William Ortland | — | (925) 819-2100 | Windows, patio, painters | Concord · Contra Costa County | — | — |
| Bay Area Grout Specialist | Bay Area Grout Specialist | — | (415) 672 6411 | Other | Brentwood · Contra Costa County | — | — |
| Bay Area Hardwood Floors | Bay Area Hardwood Floors | info@bayareahardwoodfloors.com | (510) 385 3135 | GC, remodel, ADU | San Pablo · Contra Costa County | — | — |
| Bay Area HVAC & Refrigeration | Sean Claude Mergy | — | (925) 689 2525 | HVAC | Pittsburg · Contra Costa County | — | — |
| Bay Area HVAC Service | Andrei Vasilyevich Kuznetsov | — | (510) 514 1826 | HVAC | San Ramon · Contra Costa County | — | — |
| Bay Area Koi Ponds LLC | Noah Graham Twitchell | noah@bayareakoiponds.com | (510) 984 8947 | Pool | Richmond · Contra Costa County | — | — |