| Lucky's Construction INC | Conrad Lucky White | — | (707) 480 8758 | GC, remodel, ADU | Nice · Lake County | — | — |
| Lynch Construction | Daniel Patrick Lynch | — | (707) 350 5337 | GC, remodel, ADU | Clear Lake · Lake County | — | — |
| M & M Refrigeration | M & M Refrigeration | — | (707) 816 9063 | HVAC | Cobb · Lake County | — | — |
| M A P Electric | Michael Albert Jr Peters | — | (707) 533 3637 | Electricians | Kelseyville · Lake County | — | — |
| M E Strecker | M E Strecker | — | (707) 349 1921 | GC, remodel, ADU | Kelseyville · Lake County | — | — |
| M O D Plumbing | M O D Plumbing | — | (650) 291 2636 | Other | Hidden Valley Lake · Lake County | — | — |
| M V M Construction INC | Michael Vernon Monroe | — | (530) 210 0334 | GC, remodel, ADU | Hidden Valley Lake · Lake County | — | — |
| Mac Donald Construction | Steven Thomas Mac Donald | — | (707) 963 4000 | GC, remodel, ADU | Kelseyville · Lake County | — | — |
| Mac's Marine & Land Construction INC | Macario Medina Tejeda | — | (707) 279 9414 | Other | Kelseyville · Lake County | — | — |
| Macias Drywall | Macias Drywall | — | (707) 349 2969 | Other | Kelseyville · Lake County | — | — |
| Madsen Ranch Construction Services | Brett Thomas Madsen | — | (707) 355 4733 | GC, remodel, ADU | Hidden Valley Lake · Lake County | — | — |
| Majestic Landscaping | Majestic Landscaping | — | (707) 413 8786 | Windows, patio, painters | Lucerne · Lake County | — | — |
| Martin Kutches Landscaping | Martin Kutches Landscaping | — | (415) 218 4896 | Windows, patio, painters | Lucerne · Lake County | — | — |
| Martinez Construction | Martinez Eduardo | — | (707) 349 3815 | GC, remodel, ADU | Kelseyville · Lake County | — | — |
| Mas Construction | Mark Anthony Santos | — | (707) 489 0970 | GC, remodel, ADU | Upper Lake · Lake County | — | — |
| Matthew E Nagy Construction | Matthew Ethan Nagy | — | (707) 490 2978 | GC, remodel, ADU | Lakeport · Lake County | — | — |
| Matthew Lockwood | Matthew Lockwood | — | (707) 349 3673 | GC, remodel, ADU | Kelseyville · Lake County | — | — |
| Mayo's Plumbing | Mayo's Plumbing | — | (707) 508 9808 | Other | Hidden Valley Lake · Lake County | — | — |
| Mc Comas Painting & Decorating | Mc Comas Painting & Decorating | — | (707) 570 7003 | Windows, patio, painters | Hidden Valley Lake · Lake County | — | — |
| Mc Cutcheon Construction | Ronald Dale Mc Cutcheon | — | (707) 275 2221 | GC, remodel, ADU | Upper Lake · Lake County | — | — |
| Mccarthy Tree Specialties INC | John Henry Mc Carthy | — | (650) 367 7552 | Tree | Lower Lake · Lake County | — | — |
| Mce Framing INC | Jose Cruz Estrada Bastida | — | (707) 758 4882 | Other | Clearlake · Lake County | — | — |
| Meek Construction | David Wayne Sr Meek | — | (707) 263 6335 | GC, remodel, ADU | Lakeport · Lake County | — | — |
| Mendo - Lake Garage Door Co | Rodney Lee Helsel | — | (707) 263 4830 | Other | Lakeport · Lake County | — | — |
| Mendo-lake Interiors | Mendo-lake Interiors | — | (707) 272 4717 | GC, remodel, ADU | Lakeport · Lake County | — | — |
| Mendocino Art Center | Mendocino Art Center | — | (707) 937-5818 | Windows, patio, painters | Mendocino · Lake County | — | — |
| Mertle Construction | Jeffrey Thomas Mertle | — | (707) 279 8159 | GC, remodel, ADU | Lakeport · Lake County | — | — |
| Michael Del Valle Construction | Michael Felix Del Valle | — | (707) 295 6637 | Electricians | Clearlake · Lake County | — | — |
| Michael Froio | Michael Froio | michael@michaelfroio.com | (707) 349 9100 | GC, remodel, ADU | Lakeport · Lake County | — | — |
| Michael Harris Tile Co | Michael James Harris | — | (916) 716 7850 | Other | Hidden Valley Lake · Lake County | — | — |
| Michael Russo | Michael Russo | — | (707) 809 7194 | Windows, patio, painters | Hidden Valley Lake · Lake County | — | — |
| Michael Yacorzynski | Michael Yacorzynski | — | (707) 274 5584 | GC, remodel, ADU | Nice · Lake County | — | — |
| Mike Carrillo Concrete | Mike Carrillo Concrete | — | (707) 490 6978 | Other | Kelseyville · Lake County | — | — |
| Mike Knight Construction | Michael Alan Knight | — | (707) 533 6297 | GC, remodel, ADU | Lakeport · Lake County | — | — |
| Mike Thorn's Custom Painting | Mike Thorn's Custom Painting | — | (707) 277 9695 | Windows, patio, painters | Kelseyville · Lake County | — | — |
| Mike Ullrich Construction | Michael Patrick Ullrich | — | (415) 699 5761 | GC, remodel, ADU | Kelseyville · Lake County | — | — |
| Mike's Home Improvements | Mike's Home Improvements | — | (707) 380 4952 | GC, remodel, ADU | Kelseyville · Lake County | — | — |
| Mike's Roofing | Michael Robert Barron | — | (707) 274 8593 | Other roofers | Lucerne · Lake County | — | — |
| Miller's Building And Home Improvements | Miller's Building And Home Improvements | — | (707) 376 6082 | GC, remodel, ADU | Lakeport · Lake County | — | — |
| Millerick Plumbing | Millerick Plumbing | — | (707) 495 2954 | Other | Hidden Valley Lake · Lake County | — | — |