| Diablo Telecom & Construction INC | Justin Sinclair Balough | — | (926) 349 5769 | Electricians | Concord · Contra Costa County | — | — |
| Diablo Thermal Systems INC | Sandra Kirsten Van Scyoc | — | (925) 979 1300 | HVAC | Walnut Creek · Contra Costa County | — | — |
| Diablo Valley Engineering INC | John Anthony Ii Moffat | — | (925) 250 4172 | Other | Martinez · Contra Costa County | — | — |
| Diablo Valley Heating & Air Conditioning | David Lee Earley | — | (925) 755 0792 | HVAC | Antioch · Contra Costa County | — | — |
| Diablo Valley Landscape And Design INC | Kristen Peterson O'brien | — | (925) 765 9199 | Windows, patio, painters | Danville · Contra Costa County | — | — |
| Diablo View Construction INC | Kevin Michael Schmidt | diabloviewconstruction@gmail.com | (925) 822 5144 | GC, remodel, ADU | Clayton · Contra Costa County | — | — |
| Diablo Water Heaters INC | Jonathan Henry Williams | diablowaterheaters@gmail.com | (925) 263-9444 | Other | Orinda · Contra Costa County | — | — |
| Dial Construction Co | In Seuk Jeung | — | (510) 910 3497 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| Diameza Construction | Ury Noe Diaz Martinez | — | (510) 612 2467 | GC, remodel, ADU | Pinole · Contra Costa County | — | — |
| Diamond Bridge Builders | Enoc Isai Martinez Cruz | diamondbridgebuildersinc@gmail.com | (510) 712 5672 | Other roofers | San Pablo · Contra Costa County | — | — |
| Diamond Dog Electric | Russell James De Soto | — | (925) 305 0063 | Electricians | Antioch · Contra Costa County | — | — |
| Diamond Elevator INC | Scott Allen Zoetewey | — | (925) 831 1168 | Other | San Ramon · Contra Costa County | — | — |
| Diamond Mechanical LLC | Kenneth Harold Levi | tracy@diamondmechanical.com | (623) 435-7126 | HVAC | Brentwood · Contra Costa County | — | — |
| Diamond Painting | Rios Favian Rodriguez | — | (925) 323 0043 | Windows, patio, painters | Pittsburg · Contra Costa County | — | — |
| Diamond Pavers | Diamond Pavers | — | (650) 906 6299 | Other | Antioch · Contra Costa County | — | — |
| Diamond Petroleum Services INC | Guadalupe Reyes Sanchez | — | (925) 470 0803 | Other | Antioch · Contra Costa County | — | — |
| Diamond Plumbing And Rooter | Alvarado-cruz Hugo Alberto | — | (925) 864 1568 | Other | Concord · Contra Costa County | — | — |
| Diaz Handyman Services LLC DBA Diaz Home Services | Jose De Jesus Alves-Diaz | — | (510) 684 8624 | GC, remodel, ADU | El Cerrito · Contra Costa County | — | — |
| Diaz Marin Pool Services | Kevin Arnold Diaz Arango | selvinreys11722@gmail.com | (510) 829 6808 | Pool | Richmond · Contra Costa County | — | — |
| Diaz-zamora Electric INC | Sergio Diaz-Zamora | — | (415) 240 3567 | Electricians | Richmond · Contra Costa County | — | — |
| Dickinson Construction | Ted Louis Dickinson | — | (925) 350 9837 | GC, remodel, ADU | Oakley · Contra Costa County | — | — |
| Dickson Construction | Michael David Dickson | — | (925) 324 1321 | GC, remodel, ADU | Danville · Contra Costa County | — | — |
| Diego Nieva | Diego Nieva | — | (925) 430 9489 | GC, remodel, ADU | San Ramon · Contra Costa County | — | — |
| Dig & Demo INC | John Edward Hartung | phil@digdemo.com | (877) 933 4448 | Other | San Ramon · Contra Costa County | — | — |
| Dig This INC | Joseph Anthony Zabbo | — | (925) 673 9405 | Other | Walnut Creek · Contra Costa County | — | — |
| Digs | Tanner Joseph Drake | — | (805) 509 5931 | Other | Clayton · Contra Costa County | — | — |
| Dillard Environmental Services | Melissa Anne Kirn | — | (925) 634 6850 | Other | Byron · Contra Costa County | — | — |
| Dillon Electric INC | David Russell Dillon | — | (925) 250 5912 | Electricians | Oakley · Contra Costa County | — | — |
| Dimartino Todd R | Dimartino Todd R | — | (925) 464 1570 | GC, remodel, ADU | Alamo · Contra Costa County | — | — |
| Dimension Construction INC | Joao Raimundo Nicolau | — | (510) 275 3201 | GC, remodel, ADU | Pinole · Contra Costa County | — | — |
| Dimension Painting | Dimension Painting | — | (510) 575 5157 | Windows, patio, painters | Walnut Creek · Contra Costa County | — | — |
| Dinh Brothers Construction INC | Tony Tue Dinh | — | (510) 672 7800 | GC, remodel, ADU | Brentwood · Contra Costa County | — | — |
| Dino's Contracting INC | Dino Anthony Gerosolimo | — | (925) 682 3100 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Dio Reality LLC | Daxiong He | — | (510) 200 8818 | GC, remodel, ADU | Danville · Contra Costa County | — | — |
| Dion's Construction Company | Dion Arnelle Horton | — | (510) 830 8555 | GC, remodel, ADU | Pittsburg · Contra Costa County | — | — |
| Dirt Doctor Excavating | Dirt Doctor Excavating | — | (925) 260 3636 | Other | Martinez · Contra Costa County | — | — |
| Discovery Builders INC | Louis Everett Parsons | — | (925) 682 6419 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Discovery Coatings | Gargie Rodriguez Balarbar | — | (415) 971 8207 | Other | Oakley · Contra Costa County | — | — |
| Discovery Roofing | Guillermo Chavoya Suarez | — | (925) 625 9865 | Other roofers | Oakley · Contra Costa County | — | — |
| Discovery Wall Systems INC | Cheree Michele Mendonsa | — | (925) 240 7059 | Other | Brentwood · Contra Costa County | — | — |