| J & M Elite Enterprises INC DBA J & M Landscape | Andres Rodriguez | — | (925) 360 4442 | Windows, patio, painters | Concord · Contra Costa County | — | — |
| J & M Kis Cleaning & Janitorial | Jorge M Kisielewski | — | (925) 754 3469 | Other | Antioch · Contra Costa County | — | — |
| J & R Floor Services | Joseph Salvatore Sanchez | — | (925) 998 0735 | GC, remodel, ADU | Clayton · Contra Costa County | — | — |
| J & S Steel Construction | Jay Christopher Kelling | — | (925) 708 2900 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| J A Construction Company | Santiago Torres Javier | — | (510) 375 7389 | GC, remodel, ADU | Rodeo · Contra Costa County | — | — |
| J A Design And Construction INC | Mark Christopher Weyland | — | (925) 283 6234 | GC, remodel, ADU | Lafayette · Contra Costa County | — | — |
| J A G Electric | Jose Alfredo Garcia | — | (415) 632 0820 | Electricians | Antioch · Contra Costa County | — | — |
| J A Langon Builders Incorporated | Jeff Allen Langon | — | (925) 570 5227 | GC, remodel, ADU | Diablo · Contra Costa County | — | — |
| J A M P Plumbing | J A M P Plumbing | — | (925) 597 0726 | Other | Antioch · Contra Costa County | — | — |
| J A R & Company | Ramos Jesus Alvarez | — | (510) 375 2513 | GC, remodel, ADU | San Pablo · Contra Costa County | — | — |
| J A Ronco Construction | Joseph Anthony Ronco | — | (925) 872 3049 | GC, remodel, ADU | Clayton · Contra Costa County | — | — |
| J Alba Construction INC | Alba Santos Jorge | — | (925) 595 5344 | GC, remodel, ADU | Pittsburg · Contra Costa County | — | — |
| J Alejandre Builders | Quevedo Jesus Alejandre | — | (510) 224 1235 | GC, remodel, ADU | El Sobrante · Contra Costa County | — | — |
| J And J Services INC | Joel Weinz | — | (925) 337 0681 | GC, remodel, ADU | Pittsburg · Contra Costa County | — | — |
| J And R Heating And A/c Inc. | Gomez Javier | — | (925) 548 5699 | HVAC | Oakley · Contra Costa County | — | — |
| J Andrade | J Andrade | — | (925) 752 3945 | Windows, patio, painters | Antioch · Contra Costa County | — | — |
| J B Construction | Jeff Paul Balocco | — | (925) 628 2177 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |
| J B Home Construction LLC | Jerome Edward Barber | — | (925) 440 9752 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |
| J B Landscape Management INC | Barron Jesse | — | (877) 550 2900 | Windows, patio, painters | San Ramon · Contra Costa County | — | — |
| J B R Builders INC | Barragan Jorge Ruiz | — | (925) 395 8576 | GC, remodel, ADU | Martinez · Contra Costa County | — | — |
| J B Tile Co | Jay Randolph Burns | — | (925) 766 8071 | GC, remodel, ADU | Moraga · Contra Costa County | — | — |
| J Beltran Plumbing INC | Julian Aaron Beltran | — | (510) 239 8330 | Other | Concord · Contra Costa County | — | — |
| J C & Son Construction INC | Joseph Anthony Cuevas | — | (925) 339 3607 | GC, remodel, ADU | Martinez · Contra Costa County | — | — |
| J C C INC | Cynthia Lynn Johnson | — | (925) 370 6067 | Other | Concord · Contra Costa County | — | — |
| J C Engineering And Drilling | J C Engineering And Drilling | — | (925) 382 2305 | Other | Oakley · Contra Costa County | — | — |
| J C Flooring | J C Flooring | — | (925) 457 1270 | Other | Concord · Contra Costa County | — | — |
| J C G Construction Company | John Carlos Gamez | — | (925) 513 9218 | GC, remodel, ADU | Brentwood · Contra Costa County | — | — |
| J C General Contractors INC | Jose Guadalupe Ramirez | info@jcelectricsolutions.com | (925) 377 0104 | Electricians | Moraga · Contra Costa County | — | — |
| J C Guzman Construction Company | Jose Curiel Guzman | — | (925) 516 7143 | Other | Byron · Contra Costa County | — | — |
| J C L Painting Contractor INC | Gonzalez Pedro Castaneda | jclpaintingcontractor@gmail.com | (510) 750 9401 | Windows, patio, painters | Concord · Contra Costa County | — | — |
| J C Landscaping | J C Landscaping | — | (510) 326 3851 | Windows, patio, painters | San Ramon · Contra Costa County | — | — |
| J C M Painting | J C M Painting | — | (925) 705 0581 | Windows, patio, painters | Concord · Contra Costa County | — | — |
| J C Plumbing | J C Plumbing | — | (925) 708 6647 | Other | Pinole · Contra Costa County | — | — |
| J Co Contractors INC | Julian Cortez | — | (925) 492 9080 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| J Corona Construction | Corona Jesus | — | (510) 472 3725 | GC, remodel, ADU | Pinole · Contra Costa County | — | — |
| J Cortes Construction | Cortes Preciado Julio | — | (510) 815 7083 | GC, remodel, ADU | El Sobrante · Contra Costa County | — | — |
| J D Co | John David Phillips | — | (925) 567 6125 | GC, remodel, ADU | Clayton · Contra Costa County | — | — |
| J D Construction | Jerry Dean Pacheco | — | (510) 541 7319 | GC, remodel, ADU | San Pablo · Contra Costa County | — | — |
| J D Framing INC | Jose Omar Dominguez | — | (925) 267 2053 | Other | Bay Point · Contra Costa County | — | — |
| J D Henley General Contractor | J D Henley General Contractor | — | (925) 687 7791 | GC, remodel, ADU | Alamo · Contra Costa County | — | — |