| Kin Construction | Kaleb Wishard Brown | — | (707) 477 6909 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| Kincaid Construction And Electric | Sven S Kincaid | — | (707) 696 4122 | Electricians | Sebastopol · Sonoma County | — | — |
| Kinetic Construction | James Craig Alan Nelson | — | (707) 495 0868 | Electricians | Rohnert Park · Sonoma County | — | — |
| King Built Construction | Tyler Ellis King | — | (707) 478 5144 | GC, remodel, ADU | Sebastopol · Sonoma County | — | — |
| King Construction & General Engineering INC | Kevin Anthony King | — | (707) 328 8111 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| King Electric INC | Ronald Arthur King | — | (707) 769 1604 | Electricians | Petaluma · Sonoma County | — | — |
| King Landscaping And Maintenance INC | Gaspar Ramirez | — | (707) 758 6433 | Windows, patio, painters | Rohnert Park · Sonoma County | — | — |
| King Painting | King Painting | — | (707) 695 1846 | Windows, patio, painters | Petaluma · Sonoma County | — | — |
| King's Tree Service | Jesus Ramon Heredia Chavez | — | (707) 208 5934 | Tree | Santa Rosa · Sonoma County | — | — |
| Kingdom Minded Electric | Kelly Michelle Hernandez | — | (707) 328 5060 | Electricians | Sonoma · Sonoma County | — | — |
| Kings Valley Builders INC | Hugo Caishpal | — | (707) 241 6563 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| Kintz Builders LLC | David Eugene Kintz | — | (707) 766 6878 | GC, remodel, ADU | Petaluma · Sonoma County | — | — |
| Kirby Constructions Company INC DBA Kirby Construction | York David Saccomanno | — | (707) 526 0880 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| Kirby Duff Spaulding Construction | Kirby Duff Spaulding | — | (530) 414 8558 | GC, remodel, ADU | Cloverdale · Sonoma County | — | — |
| Kirby Wilkerson | Kirby Wilkerson | kirbyw@sonic.net | (707) 529 5428 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| Kirk Buckman Electric INC DBA Kb Electric | Kirk Edward Buckman | — | (707) 528 6555 | Electricians | Santa Rosa · Sonoma County | — | — |
| Kirk Hopkin INC DBA Hopkin Construction | Kirk Kenneth Hopkin | — | (707) 321 1062 | GC, remodel, ADU | Sebastopol · Sonoma County | — | — |
| Klaus Construction | Erik Lowman Klaus | — | (707) 344 6191 | GC, remodel, ADU | Forestville · Sonoma County | — | — |
| Klebe Construction | Kolya Andre Klebe | — | (707) 477 7262 | GC, remodel, ADU | Petaluma · Sonoma County | — | — |
| Klemme Construction | Kenneth Wayne Klemme | — | (707) 865 2015 | GC, remodel, ADU | Monte Rio · Sonoma County | — | — |
| Kmk Heating & Air | Kmk Heating & Air | — | (831) 600 6630 | HVAC | Sebastopol · Sonoma County | — | — |
| Kmx Procontractors LLC | Fabian Andrew Nunez Torres | — | (901) 319 4741 | GC, remodel, ADU | Windsor · Sonoma County | — | — |
| Knight Contractors | Jerry Allen Knight | — | (707) 869 8022 | GC, remodel, ADU | Guerneville · Sonoma County | — | — |
| Knights Electric Incorporated | Robert Almond Knight | — | (707) 433 6931 | Electricians | Windsor · Sonoma County | — | — |
| Kobilt INC | Kevin Charles O'malley | — | (707) 235 4120 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| Koch Const Company | David Alfred Koch | — | (707) 575 5608 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| Koch Construction Company INC | David Alfred Koch | — | (707) 575 5608 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| Koenig Drilling | Koenig Drilling | — | (707) 888 9617 | Other | Cotati · Sonoma County | — | — |
| Kohl Mechanical | Kohl Mechanical | — | (707) 322 4348 | Other | Santa Rosa · Sonoma County | — | — |
| Kollide Woodworks | Kollide Woodworks | — | (707) 478 0200 | Other | Santa Rosa · Sonoma County | — | — |
| Koop & Nicol Floorworks | Gary Steven Koop | — | (707) 322 6549 | Other | Santa Rosa · Sonoma County | — | — |
| Korson Homes INC | Anatoliy Alex Kreshchenovskiy | korsonhomes1@gmail.com | (707) 477 4342 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| Kozy Homes | Kozy Homes | — | (707) 778 3500 | Electricians | Petaluma · Sonoma County | — | — |
| Kraal Consulting | Kraal Consulting | — | (415) 847 7506 | GC, remodel, ADU | Petaluma · Sonoma County | — | — |
| Kraftwerk | Christian Ian Lyons | — | (707) 546 1046 | Other | Santa Rosa · Sonoma County | — | — |
| Kris Kirk's Handiworks | Kris Kirk's Handiworks | — | (707) 478 1101 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| Krist Electric INC DBA Jason Krist Electric | Jason Noel Takeuchi-krist | — | (510) 421 1680 | Electricians | Santa Rosa · Sonoma County | — | — |
| Kristensen Enterprises INC | Leonard Melvin Jr Kristensen | — | (818) 209 6001 | GC, remodel, ADU | Petaluma · Sonoma County | — | — |
| Kristine Valencia Guillermo J Valencia | Guillermo Jose Valencia | — | (707) 540 1487 | GC, remodel, ADU | Petaluma · Sonoma County | — | — |
| Kunkle | Aaron James Kunkle | firstname@kunkle.com | (707) 787 8205 | GC, remodel, ADU | Sebastopol · Sonoma County | — | — |