| Justin's Professional Landscaping | Justin Tai Pham | — | (707) 631 7774 | Windows, patio, painters | Fairfield · Solano County | — | — |
| Jw Burton Construction | William James Burton | — | (530) 614 0216 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Jwb's Painting | Jwb's Painting | — | (707) 386 5314 | Windows, patio, painters | Fairfield · Solano County | — | — |
| Jwd Builders INC | James Walter Doering | james@jwdbuilders.com | (707) 704 9919 | GC, remodel, ADU | Vallejo · Solano County | — | — |
| K & K Stairs And Finish Carpentry | Garcia Horacio | — | (707) 655 0543 | Other | Vallejo · Solano County | — | — |
| K & S Mechanical INC | Stephen Dennis Babb | — | (707) 448 8575 | HVAC | Vacaville · Solano County | — | — |
| K B & B Construction INC | Yuenshu Li | — | (415) 318 9909 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| K Butler Electric | Kenneth Raymond Jr Butler | — | (707) 745 1230 | Electricians | Benicia · Solano County | — | — |
| K C Plumbing | K C Plumbing | — | (415) 728 8582 | Other | Vacaville · Solano County | — | — |
| K D Construction And Engineering | Karen Diane Duncan | — | (707) 689 3089 | GC, remodel, ADU | Dixon · Solano County | — | — |
| K L Kierce Plumbing | K L Kierce Plumbing | — | (510) 837 7057 | Other | Dixon · Solano County | — | — |
| K&p Season Landscaping | Tri Nguyen | — | (707) 515 8131 | Windows, patio, painters | Vallejo · Solano County | — | — |
| Kaban Design & Construction | Gerald Philip Kaban | — | (707) 761 9408 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Kane's Electric | David William Kane-newton | — | (415) 320 4682 | Electricians | Vallejo · Solano County | — | — |
| Karibe Holdings LLC | Reed Whitney Walker | — | (415) 516 7776 | GC, remodel, ADU | Vallejo · Solano County | — | — |
| Karrittech | Mhamed Samih Karrit | — | (707) 400 5559 | Electricians | Fairfield · Solano County | — | — |
| Kazen Custom Heating & Air | Kazen Custom Heating & Air | — | (707) 689 7204 | HVAC | Vacaville · Solano County | — | — |
| Keller Engineering & Asphalt Services INC | Darrell Eugene Letterman | — | (707) 421 1515 | Other | Fairfield · Solano County | — | — |
| Kelly Snyder | Kelly Snyder | — | (442) 899 8757 | Other | Vacaville · Solano County | — | — |
| Ken Clarks Plumbing | Ken Clarks Plumbing | — | (707) 344 5200 | Other | Vacaville · Solano County | — | — |
| Kenoyer Contracting | Jason Joe Kenoyer | — | (707) 486 0788 | GC, remodel, ADU | Benicia · Solano County | — | — |
| Kerry Wade Grading | Kerry Wade Grading | — | (707) 386 1059 | Other | Suisun City · Solano County | — | — |
| Kevin R Newcomer Construction Company | Kevin Robert Newcomer | — | (707) 205 6848 | GC, remodel, ADU | Dixon · Solano County | — | — |
| Keys Painting & Decorating | Keys Painting & Decorating | — | (410) 871 4826 | Windows, patio, painters | Vallejo · Solano County | — | — |
| Keystone Construction Group INC | Mindy Lew Nelson | — | (707) 365 8367 | GC, remodel, ADU | Fairfield · Solano County | — | — |
| Keystone Homes LLC | Benjamin Edward Nelson | — | (707) 365 8367 | GC, remodel, ADU | Fairfield · Solano County | — | — |
| Kg Pump Service | Carlos Alberto Zepeda | — | (707) 419 4146 | Other | Fairfield · Solano County | — | — |
| Khoury Mechanical LLC | Kristopher Michael| Khoury Kris Michael Khoury | — | (707) 334 6765 | HVAC | Fairfield · Solano County | — | — |
| Kim Rose Home & Garden Concepts | Kimberly Ann Rose | — | (707) 631 3044 | Windows, patio, painters | Fairfield · Solano County | — | — |
| Kingdom Fences | Gennadiy Glushchuk | — | (707) 628 0664 | Other | Vacaville · Solano County | — | — |
| Kings Construction & Remodeling INC | Hayon Moshe | — | (510) 424 3315 | GC, remodel, ADU | Vallejo · Solano County | — | — |
| Kistler Construction | Vance Paul Kistler | john@kistlerconstruction.com | (707) 688 3088 | GC, remodel, ADU | Fairfield · Solano County | — | — |
| Knock 'em Out Pest Control | Knock 'em Out Pest Control | — | (707) 864-6449 | Pest, tile roofs | Fairfield · Solano County | — | — |
| Kolob Construction | Andrew Owen Hill | — | (707) 386 1950 | GC, remodel, ADU | Fairfield · Solano County | — | — |
| Koo Mechanical INC | David Allen Roof | koomechanical@gmail.com | (707) 373 4860 | HVAC | Benicia · Solano County | — | — |
| Korifi Construction INC | George Yervasios Konstantinopoulos | — | (707) 425 8670 | GC, remodel, ADU | Fairfield · Solano County | — | — |
| Kt Construction | Kodi Rex Tatham | — | (530) 979 1191 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Kuertz Construction | Nathaniel James Kuertz | — | (707) 280 8807 | GC, remodel, ADU | Vacaville · Solano County | — | — |
| Kvon Wildfire Mitigation And Forestry Consultancy LLC | Kevin Deforest Kyle | — | (707) 210 7103 | Other | Vallejo · Solano County | — | — |
| L & D Construction | Lamore Charles Ii Jacks | info@ldconstruction.com | (510) 978 6616 | GC, remodel, ADU | Rio Vista · Solano County | — | — |