| 101 Plumbing Solutions | Francisco Javier Zaragoza | — | (415) 377 6939 | Other | Petaluma · Sonoma County | — | — |
| 101 Seamless Gutters INC | George Eugene Angell | — | (707) 566 9113 | Other | Santa Rosa · Sonoma County | — | — |
| 4 Am Systems | 4 Am Systems | — | (707) 773 4699 | Other | Petaluma · Sonoma County | — | — |
| 707 Fence Company INC | Alex Martinez | — | (707) 217 1614 | Other | Santa Rosa · Sonoma County | — | — |
| 707 Plumbers | Scott Eugene Duncan | — | (707) 292 2262 | Other | Santa Rosa · Sonoma County | — | — |
| A & L Asphalt Maintenance | A & L Asphalt Maintenance | — | (707) 528 0388 | Other | Santa Rosa · Sonoma County | — | — |
| A & L Garage Doors | Gerardo Alejandro Franco | — | (707) 538 9200 | Other | Santa Rosa · Sonoma County | — | — |
| A A & T Communications INC | Joseph Charles Augello | — | (707) 528 6812 | Other | Santa Rosa · Sonoma County | — | — |
| A B C Asphalt | A B C Asphalt | — | (707) 769 4429 | Other | Petaluma · Sonoma County | — | — |
| A Better Plumb Co LLC | Micah James Vasey | — | (707) 949 3149 | Other | Santa Rosa · Sonoma County | — | — |
| A L'ancienne Imports INC | Pascal Faivre | info@alaimports.com | (707) 996 2550 | Other | Sonoma · Sonoma County | — | — |
| A Lost Art INC | Joseph Douglas Jr Bryant | — | (415) 392 7577 | Other | Petaluma · Sonoma County | — | — |
| A O G Plumbing INC | Orozco Guerrero Alberto | — | (707) 953 2541 | Other | Rohnert Park · Sonoma County | — | — |
| A Plus Locksmith | A Plus Locksmith | — | (707) 431 0400 | Other | Windsor · Sonoma County | — | — |
| A S A P Plumbing | A S A P Plumbing | — | (707) 544 2727 | Other | Forestville · Sonoma County | — | — |
| Aaa Blasting INC | Gonzalo Diaz Zesati | — | (707) 328 3543 | Other | Santa Rosa · Sonoma County | — | — |
| Aaron Marion Arellanes | Aaron Marion Arellanes | — | (707) 595 6033 | Other | Petaluma · Sonoma County | — | — |
| Abel's Concrete Finishing | Abel's Concrete Finishing | — | (707) 799 1778 | Other | Santa Rosa · Sonoma County | — | — |
| Able Fence Company INC | Dave Castillo | — | (707) 763 2551 | Other | Petaluma · Sonoma County | — | — |
| Ace Court Repair | Ace Court Repair | — | (707) 321 7757 | Other | Santa Rosa · Sonoma County | — | — |
| Ace Insulation Incorporation | Mc Coy Dwaine | — | (707) 584 8377 | Other | Petaluma · Sonoma County | — | — |
| Acoustical Designs | Acoustical Designs | — | (707) 874 9024 | Other | Occidental · Sonoma County | — | — |
| Adalberto Cardenas | Adalberto Cardenas | — | (707) 236 7302 | Other | Santa Rosa · Sonoma County | — | — |
| Adam Z Casheros | Adam Z Casheros | — | (707) 280 8477 | Other | Rohnert Park · Sonoma County | — | — |
| Adams Surfacing | Adams Surfacing | — | (707) 528 9651 | Other | Santa Rosa · Sonoma County | — | — |
| Adobe Construction Company | Kyle Anthony Deidrick | info@adobeconstruction.com | (707) 364 3651 | Other | Penngrove · Sonoma County | — | — |
| Adobe Telcom INC | Philip Yuke Tam | — | (707) 778 7908 | Other | Petaluma · Sonoma County | — | — |
| Adolfo Mendoza Concrete Construction Incorporated | Mendoza Adolfo | — | (707) 938 9906 | Other | El Verano · Sonoma County | — | — |
| Advanced Alternative Energy Solutions INC | Rikizo Ronald Turley | — | (707) 789 9537 | Other | Petaluma · Sonoma County | — | — |
| Advanced Earthworks | Advanced Earthworks | — | (707) 744 1554 | Other | Cloverdale · Sonoma County | — | — |
| Advanced Extraction Labs | Christian Ivan Hluz | — | (707) 523 3702 | Other | Santa Rosa · Sonoma County | — | — |
| Advanced Mobile Tile | Advanced Mobile Tile | — | (707) 241 5560 | Other | Petaluma · Sonoma County | — | — |
| Advanced Stormwater Protection INC | Marilyn Leona Geney | — | (707) 953 8903 | Other | Santa Rosa · Sonoma County | — | — |
| Affordable Asphalt | Affordable Asphalt | — | (707) 331 2874 | Other | Sebastopol · Sonoma County | — | — |
| Agd General Engineering INC | Adam Gerald Dyck | — | (707) 319 8692 | Other | Cotati · Sonoma County | — | — |
| Aguiar Construction | John George Jr Aguiar | — | (707) 762 9538 | Other | Petaluma · Sonoma County | — | — |
| Aguilar Tile Installation | Aguilar Arechiga Ampelio | — | (707) 889 0314 | Other | Santa Rosa · Sonoma County | — | — |
| Ahlborn Fence & Steel INC | Cathy Ellen Ahlborn | — | (707) 573 0742 | Other | Santa Rosa · Sonoma County | — | — |
| Ahlborn Structural Steel INC | Thomas Christian Ahlborn | — | (707) 573 0742 | Other | Santa Rosa · Sonoma County | — | — |
| Ak Tile | Ak Tile | — | (415) 858 2820 | Other | Rohnert Park · Sonoma County | — | — |