| 101 Hauling Corp | Sanchez Christopher | — | (707) 500 2100 | GC, remodel, ADU | Rohnert Park · Sonoma County | — | — |
| 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 | — | — |
| 21st Century Builder | 21st Century Builder | — | (707) 975 6441 | GC, remodel, ADU | Petaluma · Sonoma County | — | — |
| 3 C Building | 3 C Building | — | (415) 246 6994 | GC, remodel, ADU | Sebastopol · Sonoma County | — | — |
| 3 D Remodeling & Renovation | 3 D Remodeling & Renovation | — | (707) 816 2646 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| 360 Tree Service | Jesse Austin Hall | — | (707) 495 2749 | Tree | Santa Rosa · Sonoma County | — | — |
| 3D Building Company | Romero Antonio Navarro | 3dbuildingeurope@gmail.com | (650) 826 7763 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| 3M Construction Company | Michael Steven Massoletti | — | (415) 308 2911 | GC, remodel, ADU | Petaluma · Sonoma County | — | — |
| 4 Am Systems | 4 Am Systems | — | (707) 773 4699 | Other | Petaluma · Sonoma County | — | — |
| 411 Painting | 411 Painting | — | (707) 393 7750 | Windows, patio, painters | Santa Rosa · Sonoma County | — | — |
| 5th Generation Painting | 5th Generation Painting | — | (707) 623 0890 | Windows, patio, painters | Petaluma · Sonoma County | — | — |
| 707 Electric INC | Freeman Doyle Harris | — | (707) 640 5657 | Electricians | Rohnert Park · Sonoma County | — | — |
| 707 Electric LLC | Reyes Mendoza | — | (707) 971 9649 | Electricians | Santa Rosa · Sonoma County | — | — |
| 707 Fence Company INC | Alex Martinez | — | (707) 217 1614 | Other | Santa Rosa · Sonoma County | — | — |
| 707 Landscapes | 707 Landscapes | — | (707) 396 0032 | Windows, patio, painters | Santa Rosa · Sonoma County | — | — |
| 707 Plumbers | Scott Eugene Duncan | — | (707) 292 2262 | Other | Santa Rosa · Sonoma County | — | — |
| 707 Plumbers INC | Kirk Lewis Walton | — | (707) 292 2262 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| 707 Plumbers INC DBA 707 Electric | Matthew Scott Duncan | — | (707) 292 2262 | HVAC | Santa Rosa · Sonoma County | — | — |
| A & B Shower Doors & Glass INC | Luis Angel Rangel Arredondo | estimate@abshowerdoorsglass.com | (707) 206 5016 | Windows, patio, painters | Santa Rosa · Sonoma County | — | — |
| A & C Noma Construction INC | Charles Noma Iv Harris | — | (707) 328 9273 | GC, remodel, ADU | Cotati · 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 & M Builders | A & M Builders | — | (707) 331 2915 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| A & M Pool Service | Albert Rosario Jr Cerrone | — | (707) 778 0215 | Pool | Petaluma · 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 B L Construction | Aaron Namaste Bruton-long | contactus@ablconstruction.com | (707) 827 3450 | GC, remodel, ADU | Graton · Sonoma County | — | — |
| A B Steel Construction | Anthony Michael Barrett | — | (707) 235 4987 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| A Better Plumb Co LLC | Micah James Vasey | — | (707) 949 3149 | Other | Santa Rosa · Sonoma County | — | — |
| A Better World Construction | Laird Davis Norgeot | — | (707) 273 2389 | GC, remodel, ADU | Sebastopol · Sonoma County | — | — |
| A C C Electric Company | Kevin Terrill Cornish | — | (510) 691 3664 | Electricians | Sebastopol · Sonoma County | — | — |
| A C Menne | A C Menne | — | (707) 318 1403 | GC, remodel, ADU | Sebastopol · Sonoma County | — | — |
| A C P Construction Company | Aaron Craig Popielak | — | (707) 637 3163 | GC, remodel, ADU | Petaluma · Sonoma County | — | — |
| A D Construction | Alan Dale Fudge | amkryukov@gmail.com | (707) 477 4646 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| A E Contractors INC | Jose Maria Rivera | — | (707) 331 7226 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| A Frame Construction | Mason Benton Lessard | — | (707) 480 0740 | GC, remodel, ADU | Sebastopol · Sonoma County | — | — |
| A G Builders | A G Builders | — | (707) 332 2156 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| A G Construction | Aaron Jason Grail | — | (707) 292 4097 | GC, remodel, ADU | Cotati · Sonoma County | — | — |
| A G S Construction | Al Geary Jr Smith | — | (707) 799 1314 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |