| Mark Collins Plumbing | Mark Collins Plumbing | — | (510) 508 8814 | Other | Pittsburg · Contra Costa County | — | — |
| Mark Darius General Contractor | Mark Darius General Contractor | — | (415) 812 3407 | GC, remodel, ADU | Martinez · Contra Costa County | — | — |
| Mark Drayer | Mark Drayer | — | (925) 253 0964 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Mark Etie DBA Plumbing Geek | Mark Etie DBA Plumbing Geek | — | (925) 270 7492 | Other | Concord · Contra Costa County | — | — |
| Mark G Rolandelli Construction INC | Mark Gerard Rolandelli | — | (925) 935 3100 | GC, remodel, ADU | Lafayette · Contra Costa County | — | — |
| Mark Petersen Corporation DBA American Plumbing | Eric Allen Petersen | — | (925) 754 4990 | Other | Antioch · Contra Costa County | — | — |
| Mark Scott Construction | Mark Allen Scott | — | (925) 944 0502 | GC, remodel, ADU | Pleasant Hill · Contra Costa County | — | — |
| Mark Scott Construction INC | Troy Raymond Brincat | — | (925) 944 0502 | GC, remodel, ADU | Pleasant Hill · Contra Costa County | — | — |
| Mark Silva DBA Twins Electric | Mark Anthony Silva | — | (925) 255 3407 | Electricians | Brentwood · Contra Costa County | — | — |
| Mark Thompson Construction INC | Mark Steven Thompson | — | (925) 552 1411 | GC, remodel, ADU | Alamo · Contra Costa County | — | — |
| Marlin Construction | Joseph Steven Marlin | — | (510) 517 6870 | GC, remodel, ADU | Clayton · Contra Costa County | — | — |
| Marlow's Maintenance | Marlow's Maintenance | — | (510) 677 4137 | GC, remodel, ADU | Crockett · Contra Costa County | — | — |
| Marnie Collier | Marnie Collier | — | (510) 719 1414 | GC, remodel, ADU | Martinez · Contra Costa County | — | — |
| Maroc Painting INC | Zahid Jamal | info@marocpainting.com | (510) 233 5373 | Windows, patio, painters | Richmond · Contra Costa County | — | — |
| Marques Construction | Antonio Luis Marques | — | (510) 812 3923 | GC, remodel, ADU | Hercules · Contra Costa County | — | — |
| Marquino Tile Marble C & M | Marquez Aguila David | — | (415) 542 6107 | Other | Pinole · Contra Costa County | — | — |
| Marroquin Construction | Jonny Misrrain Marroquin | jorge@marroquin-construction.com | (510) 502 3358 | GC, remodel, ADU | San Pablo · Contra Costa County | — | — |
| Mars Construction | Serova Maria | info@marsconstruction.com | (415) 990 4450 | GC, remodel, ADU | Pleasant Hill · Contra Costa County | — | — |
| Mars Construction And Remodeling | Daria Kugay | — | (925) 300 6181 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Martell Water Systems INC | Annette Kay Chancellor | — | (925) 432 4282 | Other | Pittsburg · Contra Costa County | — | — |
| Martin & Martin Construction | Harold T Martin | — | (408) 569 3725 | Other | Danville · Contra Costa County | — | — |
| Martin A Miller Construction | Martin Albert Miller | — | (925) 690 7007 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Martin Herzfeld | Martin Herzfeld | — | (510) 243 0190 | Electricians | El Sobrante · Contra Costa County | — | — |
| Martin Home Construction | Charles Andrew Martin | — | (925) 260 9441 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Martin Lastowski | Martin Lastowski | — | (650) 269 3456 | GC, remodel, ADU | Alamo · Contra Costa County | — | — |
| Martin P Vazquez | Martin P Vazquez | — | (510) 999 1597 | GC, remodel, ADU | El Sobrante · Contra Costa County | — | — |
| Martinez Bro's Tree INC | Jose Edenilson Martinez | — | (925) 446 9364 | Other | Concord · Contra Costa County | — | — |
| Martinez Construction | Martinez Jesus | — | (925) 822 6404 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Martinez Construction | David Jr Martinez | — | (925) 516 7915 | Other | Brentwood · Contra Costa County | — | — |
| Martinez Flooring INC | Martinez Melecio | — | (925) 584 6596 | Other | Antioch · Contra Costa County | — | — |
| Martinez Miguel Construction INC | Juan Martinez-Miguel | — | (415) 572 3912 | GC, remodel, ADU | Antioch · Contra Costa County | — | — |
| Martinez Sheet Metal INC | Carlos Raymond Bazan | — | (925) 228 3380 | HVAC | Martinez · Contra Costa County | — | — |
| Martinez Stair Company INC | Taro Erasmo Martinez | — | (925) 788 0383 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Marvin Collins Construction | Adam Lawrence Sanchez | info@marvincollinsconstruction.com | (510) 741 2100 | GC, remodel, ADU | Hercules · Contra Costa County | — | — |
| Marvin E Varela | Marvin E Varela | — | (510) 461 4865 | Electricians | Oakley · Contra Costa County | — | — |
| Mary A Ramos | Mary A Ramos | — | (510) 427 7366 | Other | Walnut Creek · Contra Costa County | — | — |
| Mason Bpp INC | Lowell Lee Mason | — | (925) 256 1092 | HVAC | Martinez · Contra Costa County | — | — |
| Mason Endeavours INC DBA Independent Power INC | Shaun Allen Mason | — | (925) 383 8747 | Electricians | Crockett · Contra Costa County | — | — |
| Masp Construction | Shay Philosoph | — | (917) 250 7668 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Massone Mechanical INC | Michael Edward Hollingshead | customerservice@massonemechanical.com | (925) 945 8501 | HVAC | Alamo · Contra Costa County | — | — |