| G Forster Construction Inc. | Gardner Forster | — | (925) 858 5343 | GC, remodel, ADU | Danville · Contra Costa County | — | — |
| G G H Roof Removal | Johanny Elvira Howard | — | (408) 205 6734 | Other roofers | El Cerrito · Contra Costa County | — | — |
| G G Z Custom Cabinets & Millworks | German Zamora Garcia | — | (925) 595 1207 | Other | Pittsburg · Contra Costa County | — | — |
| G H Construction | Greydon John Hicks | — | (925) 787 7197 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| G H Group INC | Gary Lee Hanstedt | — | (925) 485 9800 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| G I G General Engineering Contractor | Milton Dewayne Lea | — | (925) 812 1732 | Other | Oakley · Contra Costa County | — | — |
| G J R Development Co | Gary John Rapp | — | (510) 409 3930 | GC, remodel, ADU | Moraga · Contra Costa County | — | — |
| G K M Investments INC | Detrick Jason | — | (916) 706 7295 | GC, remodel, ADU | Brentwood · Contra Costa County | — | — |
| G K Welding INC | George Jamil Kassab | — | (510) 233 0133 | Other | Richmond · Contra Costa County | — | — |
| G L Rangel | Gary John Rangel | — | (925) 765 6090 | GC, remodel, ADU | Martinez · Contra Costa County | — | — |
| G Legarte Construction | Virgilio Garduce Legarte | — | (415) 988 5838 | GC, remodel, ADU | Hercules · Contra Costa County | — | — |
| G M A Construction | Gregory Michael Abram | — | (925) 325 5832 | GC, remodel, ADU | Bay Point · Contra Costa County | — | — |
| G M Marble & Granite INC | Brian Grzegorz Markiel | — | (925) 676 8385 | Other | Oakley · Contra Costa County | — | — |
| G M Piombo Construction | George Michael Piombo | — | (925) 451 2136 | GC, remodel, ADU | Danville · Contra Costa County | — | — |
| G M Pro Plumbing & Rooter | Gerber Geovany Martinez | — | (925) 705 2709 | Other | Antioch · Contra Costa County | — | — |
| G Morales Landscaping LLC | Gonzalo Rigoberto Morales Mata | — | (415) 246 1139 | Windows, patio, painters | San Pablo · Contra Costa County | — | — |
| G N Henley INC | Susan Marie Henley | — | (925) 557 6898 | GC, remodel, ADU | Clayton · Contra Costa County | — | — |
| G N S Construction Management/general Contracting | George Steven Speights | — | (415) 740 4202 | GC, remodel, ADU | San Ramon · Contra Costa County | — | — |
| G O Blessing Construction INC | Juan Antonio Guzman Soriano | goblessingconstruction@gmail.com | (510) 381 0155 | GC, remodel, ADU | San Pablo · Contra Costa County | — | — |
| G O R Construction | Gerardo Orontes Ramirez | — | (510) 407 6156 | GC, remodel, ADU | Discovery Bay · Contra Costa County | — | — |
| G P Complete Remodeling INC | Edith Alexander Majano Padilla | — | (925) 596 9007 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |
| G P Construction | Gaspar Perez Hernandez | — | (415) 378 5759 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| G Reyes Construction INC | Gregorio Reyes | — | (510) 459 5448 | GC, remodel, ADU | El Sobrante · Contra Costa County | — | — |
| G Squared Construction LLC | Glen Scott Gagon | %20info@gsquaredconstruction.com | (925) 255 1493 | GC, remodel, ADU | Orinda · Contra Costa County | — | — |
| G T O Plumbing And Rooter | Jose Manuel Saldana | — | (415) 745 6959 | Other | Richmond · Contra Costa County | — | — |
| G W Bartle Enterprises INC DBA Elliott & Son Roofing | Norman Easton Bergman | — | (925) 676 5085 | Other roofers | Concord · Contra Costa County | — | — |
| G W C Custom Builder | G W C Custom Builder | — | (925) 876 8293 | GC, remodel, ADU | Pacheco · Contra Costa County | — | — |
| G W Contracting Services INC | Gwynn Ellen Spinola | — | (510) 377 8760 | Other | Crockett · Contra Costa County | — | — |
| G&e Landscaping LLC | Da Costa Neto Jeronimo Sardinha | — | (510) 837 2611 | Windows, patio, painters | Richmond · Contra Costa County | — | — |
| G&l Construction LLC | Luis Alfredo Montes Gomez | — | (510) 691 5629 | GC, remodel, ADU | San Pablo · Contra Costa County | — | — |
| G6 Homes LLC | William Nicholas Gierok | — | (925) 354 9460 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Ga Floors INC | Amezcua-ramirez Gabriel | — | (925) 219 6620 | Other | Pittsburg · Contra Costa County | — | — |
| Ga Higgins INC | Gregory Albert Higgins | operations@gahiggins.com | (925) 969 1907 | GC, remodel, ADU | Pleasant Hill · Contra Costa County | — | — |
| Gabe Gomez | Gabe Gomez | gomezwriter@gmail.com | (925) 300 5425 | GC, remodel, ADU | Pleasant Hill · Contra Costa County | — | — |
| Gabe The Builder | Gabe The Builder | — | (925) 490 8401 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Gabo Flooring Services | Elton Nelson Gabourel | — | (925) 783 5101 | Other | Antioch · Contra Costa County | — | — |
| Gabriel Lock And Key | Gabriel Zaidenberg | — | (510) 830 6788 | Other | Danville · Contra Costa County | — | — |
| Gabriel Serrato Plumbing | Gabriel Serrato Plumbing | — | (510) 719 4252 | Other | Hercules · Contra Costa County | — | — |
| Gagetta Steam Fitting | Gregory John Gagetta | — | (925) 565 6054 | HVAC | Antioch · Contra Costa County | — | — |
| Gaia Landscape INC | Hernandez Govea Sergio | gaialandscapect@gmail.com | (925) 207 6831 | Windows, patio, painters | Concord · Contra Costa County | — | — |