| Delgado Painting | Delgado Painting | anapbm@gmail.com | (925) 481 8472 | Windows, patio, painters | Pittsburg · Contra Costa County | — | — |
| Delgado Property Management | Delgado Property Management | — | (707) 297-6800 | Property managers | Benicia · Contra Costa County | — | — |
| Dellamar Electric INC | Steve Michael Dellamar | — | (510) 504 0904 | Electricians | Moraga · Contra Costa County | — | — |
| Delpac Electric Co | Steve Joseph Baires | — | (925) 664 1749 | Electricians | Pittsburg · Contra Costa County | — | — |
| Delta Bay Concrete Cutting INC | Nicholas James Brennan | — | (925) 778 9096 | Other | Oakley · Contra Costa County | — | — |
| Delta Bay Home Inspections | Delta Bay Home Inspections | — | (925) 785-5372 | Inspectors | Antioch · Contra Costa County | — | — |
| Delta Bay Waterproofing | David Duane Moore | — | (925) 778 1224 | Windows, patio, painters | Antioch · Contra Costa County | — | — |
| Delta Breeze Heating & Air | Delta Breeze Heating & Air | — | (925) 825 3455 | HVAC | Oakley · Contra Costa County | — | — |
| Delta Climate Control | Delta Climate Control | — | (925) 634 4689 | HVAC | Discovery Bay · Contra Costa County | — | — |
| Delta Coatings INC | Jennifer Sellers Lowe | info@deltacoatings.com | (925) 642 9326 | Windows, patio, painters | Discovery Bay · Contra Costa County | — | — |
| Delta Construction | Michael John Harbert | — | (925) 775 5046 | GC, remodel, ADU | Bethel Island · Contra Costa County | — | — |
| Delta Contracting INC | Dale William Rayzor | — | (925) 963 1927 | Electricians | Discovery Bay · Contra Costa County | — | — |
| Delta Dawn Electric | Ryan Wayne Castagna | info@indiantypefoundry.com | (925) 890 9504 | Electricians | Oakley · Contra Costa County | — | — |
| Delta Diablo Garage Doors | Delta Diablo Garage Doors | — | (925) 363 9612 | Other | Antioch · Contra Costa County | — | — |
| Delta Drain And Pipe | Delta Drain And Pipe | — | (925) 956 3058 | Other | Walnut Creek · Contra Costa County | — | — |
| Delta Earthworks & Grading INC | Bryan Alexis Batres Carrera | — | (925) 506 9134 | Other | Oakley · Contra Costa County | — | — |
| Delta Electrical Construction INC | Bryan Lee Hair | — | (925) 370 3400 | Electricians | Martinez · Contra Costa County | — | — |
| Delta Fence Co INC | Steven Phillip Caldwell | frank@deltafence.com | (925) 634 5990 | Other | Brentwood · Contra Costa County | — | — |
| Delta Grading | Delta Grading | — | (925) 634 2659 | GC, remodel, ADU | Brentwood · Contra Costa County | — | — |
| Delta Grinding Company INC | Kenneth John Ferrante | — | (925) 778 3939 | Other | Knightsen · Contra Costa County | — | — |
| Delta Mechanical | Delta Mechanical | — | (925) 597 8920 | HVAC | Concord · Contra Costa County | — | — |
| Delta Pacific Builders INC | Daniel George Phippen | — | (925) 382 6520 | GC, remodel, ADU | Bethel Island · Contra Costa County | — | — |
| Delta Pacific Plumbing INC | Armando Mauricio Ceja | — | (925) 207 0069 | Other | Antioch · Contra Costa County | — | — |
| Delta Plumbing And Rooter | Delta Plumbing And Rooter | — | (925) 497 7224 | Other | Antioch · Contra Costa County | — | — |
| Delta Pro Builders | Adrian Hurtado | — | (925) 338 5915 | GC, remodel, ADU | Brentwood · Contra Costa County | — | — |
| Delta Pure Water INC | Hayek Chris | — | (925) 634 6658 | Other | Brentwood · Contra Costa County | — | — |
| Delta T HVAC | Delta T HVAC | — | (925) 204 4038 | HVAC | Oakley · Contra Costa County | — | — |
| Delta Valley Plumbing LLC | Christopher James Demetris | deltavalleyplumbing@gmail.com | (650) 281 6670 | Other | Brentwood · Contra Costa County | — | — |
| Delta Wye Electrical Services INC | Jorge David Hernandez-mendoza | — | (925) 323 5995 | Electricians | Antioch · Contra Costa County | — | — |
| Delux Painting | Carlos Alberto Perez Villa | deluxpainting1@outlook.com | (925) 595 2744 | Windows, patio, painters | Brentwood · Contra Costa County | — | — |
| Delvin Garcia Construction-a Partnership | Delvin Ronaldo Garcia Prado | — | (415) 724 6434 | Electricians | Richmond · Contra Costa County | — | — |
| Demolition Management Group INC | Sean Tavernier | — | (925) 388 0550 | GC, remodel, ADU | Moraga · Contra Costa County | — | — |
| Demomex | Jesus Antonio Hernandez | jesus3065@comcast.net | (925) 586 5461 | Other | Concord · Contra Costa County | — | — |
| Den Sevcik DBA European Craftsman | Den Sevcik DBA European Craftsman | — | (925) 671 7879 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Denalect INC | Jarl Erving Saal | — | (925) 932 2211 | Electricians | Walnut Creek · Contra Costa County | — | — |
| Dencol Construction Co INC | Dennis Dickson Lemmons | — | (925) 513 1024 | GC, remodel, ADU | Brentwood · Contra Costa County | — | — |
| Dennis Earl Taylor Construction | Dennis Earl Taylor | — | (925) 698 6608 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Dennis Severs | Dennis Severs | — | (925) 383 8726 | Other | Byron · Contra Costa County | — | — |
| Dennis Sleighter Const | Dennis Sleighter Const | — | (925) 984 5800 | GC, remodel, ADU | Clayton · Contra Costa County | — | — |
| Dependable Roofing INC | Jose Isabel Rodriguez | — | (925) 777 1417 | Other roofers | Oakley · Contra Costa County | — | — |