| Laguna Pool & Spa INC | Jose Cirilo Juarez | — | (925) 664 5251 | Pool | Antioch · Contra Costa County | — | — |
| Lala's Tile LLC | Luis Alejandro Cruz Magana | anapbm@gmail.com | (415) 602 3377 | Other | Richmond · Contra Costa County | — | — |
| Lalo's Custom Roofing INC | Eduardo Longoria | lalo@laloscustomroofing.com | (925) 597 9997 | Other roofers | Pittsburg · Contra Costa County | — | — |
| Lamorinda Builders INC | Michael Raymond Parodi | — | (925) 766-2371 | GC, remodel, ADU | Lafayette · Contra Costa County | — | — |
| Lamorinda Construction & Consulting | Kari Jo Grosz | — | (925) 899 7201 | GC, remodel, ADU | Lafayette · Contra Costa County | — | — |
| Lamorinda Construction Corp | Hooman Jenab | — | (925) 255 3955 | GC, remodel, ADU | Pleasant Hill · Contra Costa County | — | — |
| Lamorinda Fence Co | Edward James Jr Makrakis | — | (925) 890 6627 | Other | Concord · Contra Costa County | — | — |
| Lamorinda INC | Victor Manuel Rangel | — | (925) 899 1632 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Lamorinda Kitchen And Bath | Ryan Michael Trudeau | — | (925) 238 6806 | GC, remodel, ADU | Lafayette · Contra Costa County | — | — |
| Lamorinda Painting | Lamorinda Painting | lamorindapainting@gmail.com | (925) 890 0361 | Windows, patio, painters | Lafayette · Contra Costa County | — | — |
| Lamorinda Pavers | Lamorinda Pavers | — | (925) 389 0119 | Other | Lafayette · Contra Costa County | — | — |
| Lance Plumbing Solutions | Carlos Augusto Jr Lancellotti | lanceplumbingsolutions@gmail.com | (415) 996 9905 | Other | Brentwood · Contra Costa County | — | — |
| Landa Plumbing INC | Elias Jr Landa | 291-6628landaplumbinginc@gmail.comhttps | (925) 305 7847 | Other | Bay Point · Contra Costa County | — | — |
| Landon Pool And Spa | Landon Pool And Spa | — | (925) 354 3904 | Pool | Oakley · Contra Costa County | — | — |
| Landscape Care Co | Nikolas Alexander Vizcay | eben@eyebytes.com | (707) 590 0660 | Windows, patio, painters | Martinez · Contra Costa County | — | — |
| Landscape Dynamics | Landscape Dynamics | — | (925) 829 8970 | GC, remodel, ADU | San Ramon · Contra Costa County | — | — |
| Landscape Experts INC | Aaron Joseph Gentile | — | (925) 397 3787 | GC, remodel, ADU | Danville · Contra Costa County | — | — |
| Landspaces LLC | Peter Thomas Rohan | — | (510) 672 1642 | Windows, patio, painters | Richmond · Contra Costa County | — | — |
| Langdon - Gionet & Associates INC | Christopher Lawrence Langdon | — | (925) 323 6582 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Lantech Design | Eduardo Solis Garcia | eduardo.lantechdesign@gmail.com | (925) 944 5782 | Windows, patio, painters | Pleasant Hill · Contra Costa County | — | — |
| Lara's Concrete INC | Luis Humberto Lara | info@larasconcrete.com | (925) 246 0096 | Other | Martinez · Contra Costa County | — | — |
| Laran Construction LLC | Jesus Israel Reyes Ambriz | — | (925) 584 7523 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |
| Larios And Sons | Larios And Sons | — | (510) 799 5240 | Other | Hercules · Contra Costa County | — | — |
| Larracilla General Construction | Larracilla-de Rosas Higinio | — | (925) 332 9174 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |
| Larry C Cross | Larry C Cross | — | (925) 899 4759 | GC, remodel, ADU | Alamo · Contra Costa County | — | — |
| Larry Flores Construction | Flores Larry | — | (925) 437 1733 | GC, remodel, ADU | Brentwood · Contra Costa County | — | — |
| Larry Gorman Cabinets | Larry Gorman Cabinets | — | (925) 584 6101 | Other | Antioch · Contra Costa County | — | — |
| Larry Lee Winston | Larry Lee Winston | — | (925) 812 1775 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |
| Larry Vo | Larry Vo | — | (510) 944 8600 | GC, remodel, ADU | San Pablo · Contra Costa County | — | — |
| Larry's Custom Quality Painting And Decorating | Larry James Hayne | — | (925) 768 0744 | Windows, patio, painters | Pleasant Hill · Contra Costa County | — | — |
| Larson Pools INC | Steven Larry Larson | plaster@larsonpools.com | (925) 260 8422 | Pool | Antioch · Contra Costa County | — | — |
| Latteri's Painting & Decorating | Latteri's Painting & Decorating | — | (925) 998 3764 | Windows, patio, painters | Martinez · Contra Costa County | — | — |
| Lawn Gone | Lawn Gone | lawngonepdx@gmail.com | (707) 799 8238 | Windows, patio, painters | Richmond · Contra Costa County | — | — |
| Lawrence Construction INC | Thomas Mc Mullen Lawrence | info@lawrence-construction.com | (510) 237 3421 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| Lawrence E Munn | Lawrence E Munn | — | (925) 229 2324 | GC, remodel, ADU | Martinez · Contra Costa County | — | — |
| Lawrence E Tonti | Lawrence E Tonti | — | (925) 286 4170 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Lawrence Electric & Construction | Lawrence Edward Salisbury | — | (925) 625 7597 | Electricians | Oakley · Contra Costa County | — | — |
| Lawton Construction & Restoration INC | Lawton Construction & Restoration INC | help@lawtoncr.com | (866) 990-5150 | Restoration | Benicia · Contra Costa County | — | — |
| Laz N General Construction | Lazaro Peralta Nemias | — | (925) 864 2300 | GC, remodel, ADU | Martinez · Contra Costa County | — | — |
| Lb Harbors Roofing INC | Melvin Alexander Henriquez | — | (925) 338 0080 | Other roofers | Walnut Creek · Contra Costa County | — | — |