| Bogarin Painting INC | Bogarin Ricardo Conchas | — | (510) 829 6619 | Windows, patio, painters | Richmond · Contra Costa County | — | — |
| Bohannan Concrete INC | Garrett Brent Bohannan | — | (925) 932 2192 | Other | Alamo · Contra Costa County | — | — |
| Bohemia Roofing | Vaclav Vashek Zak | — | (925) 768 2029 | Other roofers | Oakley · Contra Costa County | — | — |
| Bohemian Roots | Bohemian Roots | — | (510) 717 2236 | Windows, patio, painters | Concord · Contra Costa County | — | — |
| Bolt Electric | Mark Steven Milz | — | (975) 577 0696 | Electricians | Danville · Contra Costa County | — | — |
| Bolt INC | Leon Gramajo Roberto I De | — | (415) 275 0776 | GC, remodel, ADU | Pleasant Hill · Contra Costa County | — | — |
| Bomac's INC | Susan Lenore Phalen | — | (925) 935 5071 | Other | Walnut Creek · Contra Costa County | — | — |
| Bondoc Construction | Vener Dela Cruz Bondoc | — | (415) 407 3877 | GC, remodel, ADU | Hercules · Contra Costa County | — | — |
| Bonner Electric | David Brian Bonner | — | (510) 377 7244 | Electricians | Concord · Contra Costa County | — | — |
| Boothline Electric | Lee Scott Hall | info@boothlineelectric.com | (408) 930 7361 | Electricians | El Cerrito · Contra Costa County | — | — |
| Borges Soares Interlocking Pavers | Borges Soares Interlocking Pavers | — | (510) 660 7147 | Other | Richmond · Contra Costa County | — | — |
| Boschert / Dokana | Boschert / Dokana | iamtim66@gmail.com | (510) 231 9089 | GC, remodel, ADU | El Sobrante · Contra Costa County | — | — |
| Bosco Development & Construction INC | Erick Alonso Chavez Urena | — | (925) 497 6148 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Boscolai Construction | Kwong Wai Lai | — | (415) 636 8999 | HVAC | Danville · Contra Costa County | — | — |
| Bosman Woodcraft | Bosman Woodcraft | — | (925) 382 5588 | GC, remodel, ADU | Lafayette · Contra Costa County | — | — |
| Boss Mechanical | Boss Mechanical | — | (510) 812 4051 | HVAC | Richmond · Contra Costa County | — | — |
| Botelho Const Co | Steven Mickel Botelho | — | (925) 330 2952 | GC, remodel, ADU | Danville · Contra Costa County | — | — |
| Bower Company | Ronald Kieth Bower | — | (916) 206 4059 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Boydstun Construction INC | Jonathan David Boydstun | — | (925) 370 7070 | GC, remodel, ADU | Martinez · Contra Costa County | — | — |
| Bq Construction INC | Diego Teodardo Nieva Carrasco | info@bqconstruction.com | (650) 630 7928 | GC, remodel, ADU | San Ramon · Contra Costa County | — | — |
| Brace Restoration | Brace Restoration | — | (415) 846 1044 | GC, remodel, ADU | Pinole · Contra Costa County | — | — |
| Bracelin Company | Brent Alan Sr Bracelin | — | (510) 815 4633 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Bracelin Construction | Brent Alan Sr Bracelin | — | (510) 386 3480 | GC, remodel, ADU | Alamo · Contra Costa County | — | — |
| Brachi Construction | Pedro Eduardo Crevelari | — | (510) 778 9502 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| Brackett Construction | Angel Kim Brackett | — | (925) 765 0768 | GC, remodel, ADU | Lafayette · Contra Costa County | — | — |
| Braddock & Logan Services INC | Joseph Edwin Raphel | — | (925) 736 4000 | GC, remodel, ADU | Danville · Contra Costa County | — | — |
| Bradley Tanks INC | Norman Leroy Christensen | — | (925) 229 2900 | Other | Danville · Contra Costa County | — | — |
| Brady Construction | Michael John Brady | info@bradyconstruction.com | (925) 207 1836 | GC, remodel, ADU | Bay Point · Contra Costa County | — | — |
| Brains Automation | Brains Automation | — | (510) 776 9972 | Electricians | Walnut Creek · Contra Costa County | — | — |
| Branagh Development INC | Matthew Ryan Branagh | — | (925) 743 9500 | GC, remodel, ADU | Lafayette · Contra Costa County | — | — |
| Brand Kitchens & Design | Brand Kitchens & Design | — | (415) 680 5454 | GC, remodel, ADU | Brentwood · Contra Costa County | — | — |
| Brandon Construction INC | Brandon Scott Quan | — | (925) 867 3811 | GC, remodel, ADU | San Ramon · Contra Costa County | — | — |
| Brandon Welch Construction | Brandon Orval Welch | — | (925) 354 6668 | GC, remodel, ADU | Brentwood · Contra Costa County | — | — |
| Brannick & Associates Painting Services | Patrick Sean Brannick | — | (510) 435 7918 | Windows, patio, painters | El Sobrante · Contra Costa County | — | — |
| Brasmerica Pavers System INC | Carlos Eduardo Barbosa | — | (925) 483 5341 | Other | San Pablo · Contra Costa County | — | — |
| Bravo Building Co INC | Gregory Paul Di Loreto | — | (925) 432 1314 | GC, remodel, ADU | Clayton · Contra Costa County | — | — |
| Brawdus Construction | Davie Brawdus Jr Bushong | — | (925) 382 1356 | GC, remodel, ADU | Brentwood · Contra Costa County | — | — |
| Brazil Electric INC | Michael Anthony Brazil | — | (925) 944 9600 | Electricians | Pleasant Hill · Contra Costa County | — | — |
| Breeden Engineering | Breeden Engineering | — | (510) 821 1002 | Other | Concord · Contra Costa County | — | — |
| Breeze Heating & Cooling | Breeze Heating & Cooling | — | (415) 312 7079 | HVAC | Antioch · Contra Costa County | — | — |