| Lsl Construction INC | Andrew Dean Meyer | — | (707) 634 8575 | GC, remodel, ADU | Sebastopol · Sonoma County | — | — |
| Lucas Bell Plumbing & Heating | Lucas Bell Plumbing & Heating | — | (707) 318 0631 | HVAC | Rohnert Park · Sonoma County | — | — |
| Lucas Construction | Gregory Joel Lucas | — | (707) 585 7400 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| Lucas Construction Company | John Merritt Lucas | — | (707) 484 9700 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| Lucas Robert Monroe | Lucas Robert Monroe | — | (707) 331 3121 | GC, remodel, ADU | Sebastopol · Sonoma County | — | — |
| Lucas Russell Collins | Lucas Russell Collins | — | (707) 794 9447 | Other | Rohnert Park · Sonoma County | — | — |
| Lucero Kline INC | Grace Rose Lucero | — | (707) 326 5161 | GC, remodel, ADU | Healdsburg · Sonoma County | — | — |
| Luciani Pump Company INC | Derek Donald Olsen | info@lucianipump.com | (707) 433 4424 | Other | Healdsburg · Sonoma County | — | — |
| Lucky Dog Painting | Lucky Dog Painting | — | (707) 799 3644 | Windows, patio, painters | Petaluma · Sonoma County | — | — |
| Lucky Garage Door | Lucky Garage Door | — | (707) 771 9312 | Other | Windsor · Sonoma County | — | — |
| Ludlow Plumbing | Ludlow Plumbing | — | (707) 787 6397 | Other | Petaluma · Sonoma County | — | — |
| Luedecke Woodworks | Luedecke Woodworks | — | (707) 766 9313 | Other | Petaluma · Sonoma County | — | — |
| Luis Drywall | Luis Drywall | — | (707) 338 0205 | Other | Petaluma · Sonoma County | — | — |
| Luke's Construction Service | Luke James | — | (707) 328 8162 | GC, remodel, ADU | Windsor · Sonoma County | — | — |
| Lukkasson Earthworks | Lukkasson Earthworks | — | (707) 396 2072 | Other | Forestville · Sonoma County | — | — |
| Lumitech Electric INC | Maldonado Jahiro Arango | jarango@lumitechelectric.com | (510) 988 2724 | Electricians | Petaluma · Sonoma County | — | — |
| Lunny Engineering INC | Joseph Anthony Iii Lunny | — | (707) 996 1284 | Other | Sonoma · Sonoma County | — | — |
| Lunt Heating & Air Conditioning INC | Samuel Cook Lunt | — | (707) 545 0741 | HVAC | Santa Rosa · Sonoma County | — | — |
| Lush Planet Electric And Building | Michael David Stokes | — | (707) 922 4790 | Electricians | Cazadero · Sonoma County | — | — |
| Lux Lighting Design & Electrical | Cristian Emanuel Albino | — | (415) 827 8236 | Electricians | Santa Rosa · Sonoma County | — | — |
| Lux Metals INC | David Andrew Wiggins | — | (707) 546 1821 | HVAC | Santa Rosa · Sonoma County | — | — |
| Luxolite Electric LLC | Manuel Alejandro Magana Bucio | — | (707) 721 7377 | Electricians | Sonoma · Sonoma County | — | — |
| Luxur Painting & Decorating | Luxur Painting & Decorating | — | (707) 569 6000 | Windows, patio, painters | Santa Rosa · Sonoma County | — | — |
| Luzvin O De Leon Construction INC | Luzvin Osmin De Leon De Leon | — | (415) 609 1800 | GC, remodel, ADU | Petaluma · Sonoma County | — | — |
| Lynn E Barr | Lynn E Barr | — | (707) 953 1294 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| Lytle INC | Julie Anne Lytle | — | (707) 545 1822 | HVAC | Santa Rosa · Sonoma County | — | — |
| M & C Drywall Services INC | Cesar Carrillo | — | (707) 486 2739 | Other | Santa Rosa · Sonoma County | — | — |
| M & M Plumbing | M & M Plumbing | — | (707) 799 0205 | Other | Santa Rosa · Sonoma County | — | — |
| M & Z Electrical Contractor | Mahmud Rashid Al Zahawi | — | (707) 738 1551 | Electricians | Sonoma · Sonoma County | — | — |
| M A C C Construction | James Edward Hughes | — | (707) 732 6391 | GC, remodel, ADU | Glen Ellen · Sonoma County | — | — |
| M A Mc Clish Excavating INC | Michael Alynn Mc Clish | — | (707) 538 7079 | Other | Santa Rosa · Sonoma County | — | — |
| M C A Creative | M C A Creative | — | (707) 318 4331 | Other | Sonoma · Sonoma County | — | — |
| M C Davis Construction | Mark Cameron Davis | — | (707) 484 1858 | GC, remodel, ADU | Penngrove · Sonoma County | — | — |
| M D B Interiors INC | Michael Joseph Daly | — | (415) 444 5300 | GC, remodel, ADU | Petaluma · Sonoma County | — | — |
| M D C Construction | Matthew Donald Chapman | — | (415) 209 3696 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| M E Olson Construction | Michael Edward Olson | — | (707) 321 4409 | GC, remodel, ADU | Petaluma · Sonoma County | — | — |
| M Ferris Electric INC | Mark Philip Ferris | — | (707) 762 2626 | Electricians | Petaluma · Sonoma County | — | — |
| M G O Construction | Guzman Ortiz Martin | — | (707) 217 9037 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| M G Pro Builders INC | Gomez Miguel Gonzalez | — | (707) 308 4436 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| M Heizer Tile Stone INC | Matthew Clementino Heizer | — | (707) 338 1452 | Other | Petaluma · Sonoma County | — | — |