| Linco Electric INC | Dannette Linn Pastor | — | (925) 516 6596 | Electricians | Byron · Contra Costa County | — | — |
| Linda Vista Landscape | Linda Vista Landscape | 1-818-441-8033gflores@lindavistalandscape.com | (925) 766 3048 | Windows, patio, painters | Oakley · Contra Costa County | — | — |
| Line Ops Consulting LLC | Blake Richard Edwards | — | (408) 220 4906 | Electricians | Brentwood · Contra Costa County | — | — |
| Lio Welding Services LLC | Aurelio Antonio Gutierrez Arciga | — | (307) 749 0280 | Other | Hercules · Contra Costa County | — | — |
| Lion Electric | Ramirez Rivera Victor | — | (510) 253 9249 | Electricians | El Sobrante · Contra Costa County | — | — |
| Lion Group Construction | Ohad Arye Finkel | — | (925) 639 7770 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Lionheart Homes INC | David Thomas Seeno | — | (925) 483 2589 | GC, remodel, ADU | Pleasant Hill · Contra Costa County | — | — |
| Liotta And Son Construction | Marc French Liotta | — | (925) 286 2232 | GC, remodel, ADU | Lafayette · Contra Costa County | — | — |
| Liquitech Fire Systems INC | Justin Curtis Maxwell | — | (925) 338 0555 | Other | San Ramon · Contra Costa County | — | — |
| Liri Builders | Idan Harush | — | (925) 393 9898 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |
| Liske Construction | Patrick Dale Liske | — | (415) 990 0070 | GC, remodel, ADU | Pinole · Contra Costa County | — | — |
| Littlefield General Contracting | Jason Thomas Littlefield | — | (415) 377 9195 | GC, remodel, ADU | Pinole · Contra Costa County | — | — |
| Live Oak Construction INC | Thomas Michael Jr Tuohy | — | (925) 260 3351 | GC, remodel, ADU | Alamo · Contra Costa County | — | — |
| Living Waters Construction Company | Perez Francisco | — | (925) 759 0684 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |
| Llano Grande Landscaping Corporation | Kristopher Lee Dasso | — | (925) 418 5626 | GC, remodel, ADU | Oakley · Contra Costa County | — | — |
| Lloyd E Kristof Construction | Lloyd Eugenio Kristof | — | (510) 504 5658 | GC, remodel, ADU | Danville · Contra Costa County | — | — |
| Lloyd R Paulsell | Lloyd R Paulsell | — | (510) 787 3037 | Other | Crockett · Contra Costa County | — | — |
| Lloyd's Custom Woodwork INC | David Eric Lloyd | — | (925) 260 9744 | GC, remodel, ADU | Pleasant Hill · Contra Costa County | — | — |
| Lm Landscaping | Lm Landscaping | — | (925) 752 3074 | Windows, patio, painters | Pittsburg · Contra Costa County | — | — |
| Lmh Scaffold | Noel Antonio Villafranco | info@lmhscaffold.com | (510) 260 1425 | Other | Richmond · Contra Costa County | — | — |
| Lnc Construction INC | Mariano Alfredo Aquino Flores | — | (510) 932 4380 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| Local Tree INC | Justin Vance Anderson | — | (415) 684 4224 | Tree | Richmond · Contra Costa County | — | — |
| Lodestar Electric | Thomas Charles Kolinski | — | (847) 828 4703 | Electricians | El Cerrito · Contra Costa County | — | — |
| Logan Security Systems | Jeffrey Wayne Logan | — | (925) 325 6418 | Alarm and generators | Oakley · Contra Costa County | — | — |
| Lombo Electric INC | Steven Lawrence Lombardi | — | (925) 367 4601 | Electricians | Pleasant Hill · Contra Costa County | — | — |
| Lon B Williams | Lon B Williams | — | (925) 708 4800 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Longshore Handyman LLC | David Allen Cotton | %20longshorehandyman@gmail.com | (510) 609 5200 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| Lonnie Jay Arguello DBA L A Building Services | Lonnie Jay Arguello | — | (925) 216 3163 | GC, remodel, ADU | Brentwood · Contra Costa County | — | — |
| Lontz Construction | Peter Charles Lontz | — | (209) 323 0065 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Lopez Build Group | Fernando Daniel Lopez | — | (925) 448 4175 | GC, remodel, ADU | Oakley · Contra Costa County | — | — |
| Lopez Construction Company | Martin Jr Lopez | — | (510) 228 6794 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |
| Lopez Home Improvement INC | Martinez Guillermo Lopez | — | (510) 932 7725 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| Lopez Landscaping | Lopez Landscaping | — | (510) 334 6159 | Windows, patio, painters | El Sobrante · Contra Costa County | — | — |
| Lopez Landscaping Company | Jose Arturo Lopez | — | (925) 446 5062 | Windows, patio, painters | Concord · Contra Costa County | — | — |
| Lopez Reglazing & General Construction INC | Pedro Damian Ramirez Lopez | — | (323) 476 5563 | GC, remodel, ADU | Bay Point · Contra Costa County | — | — |
| Loren Construction Company | David Loren Zapf | — | (925) 642 5005 | GC, remodel, ADU | Brentwood · Contra Costa County | — | — |
| Lorentson Painting & Decorating | Lorentson Painting & Decorating | — | (925) 947 3938 | Windows, patio, painters | Walnut Creek · Contra Costa County | — | — |
| Lori J Ortiz Wood Floors | Lori J Ortiz Wood Floors | — | (925) 788 3599 | Other | Martinez · Contra Costa County | — | — |
| Lot Fence Works LLC | Luis Enrique Ortiz | — | (925) 440 8390 | Other | Concord · Contra Costa County | — | — |
| Lou's Construction | Louis Frank Tageson | ltageson@lousconstruction.com | (510) 384 6077 | GC, remodel, ADU | Clayton · Contra Costa County | — | — |