| Atmosair Heating And Air Conditioning | Atmosair Heating And Air Conditioning | — | (707) 322 6564 | HVAC | Sebastopol · Sonoma County | — | — |
| Atmosphere Heating And Air Conditioning | Atmosphere Heating And Air Conditioning | — | (707) 547 7594 | HVAC | Santa Rosa · Sonoma County | — | — |
| Atrisco Construction | Hector Alexis Paniagua Atrisco | alexatrisco@icloud.com | (707) 304 1557 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| Ats | Robert Eric Ulicny | — | (707) 585 0810 | Other | Rohnert Park · Sonoma County | — | — |
| Attention To Detail | Attention To Detail | details@attentiontodetail.com | (415) 336 2574 | Windows, patio, painters | Petaluma · Sonoma County | — | — |
| Attune Landscape Co | John William Matthies | — | (707) 755 4730 | Windows, patio, painters | Sebastopol · Sonoma County | — | — |
| August - Jaye Construction | Eddy August Deniz | — | (707) 766 0927 | GC, remodel, ADU | Rohnert Park · Sonoma County | — | — |
| Aurelio's Old World Iron Works | Lofaro Aurelio | — | (707) 762 1516 | GC, remodel, ADU | Petaluma · Sonoma County | — | — |
| Austin Construction Co | Brooks Reed Austin | — | (707) 318 7501 | GC, remodel, ADU | Occidental · Sonoma County | — | — |
| Austin Creek Construction | Raymond Saturnino Jr Barrio | — | (707) 632 5024 | GC, remodel, ADU | Cazadero · Sonoma County | — | — |
| Austin Creek Services INC | Homer Peter Canelis | — | (707) 545 5550 | Other | Santa Rosa · Sonoma County | — | — |
| Austin Orion Shaffer | Austin Orion Shaffer | — | (707) 591 1881 | GC, remodel, ADU | Sebastopol · Sonoma County | — | — |
| Austin Parnow Landscape Design | Austin Parnow Landscape Design | — | (707) 508 7982 | Windows, patio, painters | Windsor · Sonoma County | — | — |
| Automatic Gate Specialist INC | Richard Michael Naujokaitis | — | (707) 837 9120 | GC, remodel, ADU | Healdsburg · Sonoma County | — | — |
| Av Electric INC | Jose Alejandro Valdovines Ortiz | — | (707) 931 9420 | Electricians | Rohnert Park · Sonoma County | — | — |
| Av Stone Surfaces INC | Badillo Alejandro Vazquez | — | (707) 694 2407 | Other | Petaluma · Sonoma County | — | — |
| Avcon Constructors INC | Arthur Leonard Vollert | — | (707) 939 4870 | Electricians | Vineburg · Sonoma County | — | — |
| Avila Electric INC | Avila Salvador | avilaiii@hotmail.com | (707) 843 5557 | Electricians | Santa Rosa · Sonoma County | — | — |
| Avila's Painting | Avila's Painting | efren@avilaspainting.com | (415) 858 5738 | Windows, patio, painters | Rohnert Park · Sonoma County | — | — |
| Avilla Masonry | Avilla Masonry | — | (707) 544 3229 | Other | Santa Rosa · Sonoma County | — | — |
| Avocet Construction Services | Mark Carroll Johnson | — | (707) 342 7284 | GC, remodel, ADU | Sebastopol · Sonoma County | — | — |
| Avrey And Reese Builders | Avrey And Reese Builders | — | (707) 249 2501 | GC, remodel, ADU | Sebastopol · Sonoma County | — | — |
| Award Roofing INC | Rick Floyd Ward | — | (707) 939 1645 | Other roofers | Sonoma · Sonoma County | — | — |
| Award Winning Masonry | Award Winning Masonry | — | (707) 861 9850 | Other | Sebastopol · Sonoma County | — | — |
| Awning Pros | Paul Kirk Nielsen | — | (707) 484 4616 | Other | Petaluma · Sonoma County | — | — |
| Axiom Construction | Ian Michael Maclean | — | (415) 609 9111 | GC, remodel, ADU | Sebastopol · Sonoma County | — | — |
| Azevedo Construction | Ceasar Mariano Azevedo | — | (707) 396 1083 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| Azevedo Flooring | Azevedo Flooring | — | (707) 694 9205 | Other | Geyserville · Sonoma County | — | — |
| Azevedo Plumbing | Azevedo Plumbing | — | (707) 481 1189 | Other | Windsor · Sonoma County | — | — |
| Aztec Drywall INC | Lopez Alfredo | — | (707) 981 7977 | Other | Petaluma · Sonoma County | — | — |
| Aztec Masonry | Aztec Masonry | — | (707) 843 8101 | Other | Santa Rosa · Sonoma County | — | — |
| Aztrack Construction Corporation | Nicholas Wayne Deiter | — | (707) 773 0473 | Other | Petaluma · Sonoma County | — | — |
| B & J Construction | B & J Construction | — | (707) 996-1454 | GC, remodel, ADU | Sonoma · Sonoma County | — | — |
| B & L Glass | Matthew Deen Iribarne | sales@blglass.com | (707) 210-0457 | Windows, patio, painters | Santa Rosa · Sonoma County | — | — |
| B & P Construction | Robert Mendel Parr | — | (707) 763 4576 | GC, remodel, ADU | Petaluma · Sonoma County | — | — |
| B A Electric INC | James Robert Parker | awilson@baelectric.com | (707) 292 0848 | Electricians | Rohnert Park · Sonoma County | — | — |
| B A M Plumbing INC | Blake Anthony Moran | info@bamplumbing.com | (707) 978 0867 | Other | Windsor · Sonoma County | — | — |
| B And D Excavation And Construction | Burns Sean | — | (415) 745 6246 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| B C Builders | B C Builders | — | (707) 217 7726 | GC, remodel, ADU | Cloverdale · Sonoma County | — | — |
| B C C General Contractors INC | David Wayne Baker | — | (707) 664 1800 | GC, remodel, ADU | Cotati · Sonoma County | — | — |