| Anzures Lath & Plaster INC | Anzures Andres | — | (650) 739 9554 | Other | Healdsburg · Sonoma County | — | — |
| Ap Construction | Andrew Jerome Pimentel | — | (415) 306 1253 | GC, remodel, ADU | Petaluma · Sonoma County | — | — |
| Apex Construction Services | Thomas Jarred Linfante | — | (707) 364 0606 | GC, remodel, ADU | El Verano · Sonoma County | — | — |
| Apex Contractors INC | Mark Anthony Smith | — | (707) 484 6652 | GC, remodel, ADU | Petaluma · Sonoma County | — | — |
| Apex Heating & Air | Apex Heating & Air | — | (707) 477 8647 | HVAC | Windsor · Sonoma County | — | — |
| Apex Home Resources INC | Roberto T Murcia | — | (415) 828 4636 | Other | Santa Rosa · Sonoma County | — | — |
| Apex Landscape Lighting & Audio | Jared Vahram Platsis | — | (415) 448 7035 | Other | Petaluma · Sonoma County | — | — |
| Apex Window Coverings | Apex Window Coverings | alex@apexwindowcoverings.com | (707) 293 0264 | Other | Santa Rosa · Sonoma County | — | — |
| Apg Construction INC | George Russell Moskoff | — | (707) 636 4816 | Electricians | Santa Rosa · Sonoma County | — | — |
| Apple Dog | Mason Lee Belden | — | (707) 481 1124 | GC, remodel, ADU | Sebastopol · Sonoma County | — | — |
| Apple Renovations | Apple Renovations | bard@sonomacountypermit.com | (707) 484 8669 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| Applied Building Solutions INC | Jason Anatole Offill | — | (707) 865 4186 | GC, remodel, ADU | Monte Rio · Sonoma County | — | — |
| Applied Shotcrete | Applied Shotcrete | oscar@appliedshotcrete.com | (415) 454 8178 | Other | Sebastopol · Sonoma County | — | — |
| Aqua Solutions Pool & Spa Services | Robert Miles Christian | — | (707) 540 5920 | Pool | Petaluma · Sonoma County | — | — |
| Aquacraft Plumbing INC | Ramzi Ibrahim Soudah | aquacraftplumbing.us@gmail.com | (707) 757 3838 | Other | Santa Rosa · Sonoma County | — | — |
| Aquapro Pool Care LLC | James Ralph Iii Jackson | — | (251) 533 6641 | Pool | Petaluma · Sonoma County | — | — |
| Aquascape | Todd Frances Hendrickson | — | (707) 769 7212 | Pool | Petaluma · Sonoma County | — | — |
| Aquascape Pool Service INC | Todd Frances Hendrickson | — | (707) 762 0300 | Pool | Petaluma · Sonoma County | — | — |
| Aquatic Pools Sonoma County | Leffler Alan Brown | — | (707) 584 0436 | Pool | Rohnert Park · Sonoma County | — | — |
| Aquatic Resource Management | Anthony Charles Domenici | — | (707) 230 2075 | Other | Sebastopol · Sonoma County | — | — |
| Aquila Low Voltage | Aquila Low Voltage | — | (415) 302 8555 | Other | Santa Rosa · Sonoma County | — | — |
| Ar Drywall Services | Ramirez Lopez Abel | — | (707) 322 2690 | Windows, patio, painters | Rohnert Park · Sonoma County | — | — |
| Araujo & Maldonado Construction & Remodeling INC | Lusvin Armando Araujo Rac | — | (707) 658 8002 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| Arbor Fence INC | Genevieve Catherine Van Bebber | — | (707) 938 3133 | Windows, patio, painters | Sonoma · Sonoma County | — | — |
| Arborcare Group INC | Villar Mario Del | — | (707) 755 4138 | Tree | Santa Rosa · Sonoma County | — | — |
| Arborists That Climb INC | Tyler Michael Woodbury | — | (707) 526 1104 | Tree | Santa Rosa · Sonoma County | — | — |
| Arbors General Contractor LLC | Michael Anthony Smith | — | (707) 542 4862 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| Arcadio G Fogal | Arcadio G Fogal | — | (707) 953 3633 | GC, remodel, ADU | Guerneville · Sonoma County | — | — |
| Arce Construction Solutions INC | Raciel Saul Antuna Arce | — | (707) 503 8337 | GC, remodel, ADU | Sebastopol · Sonoma County | — | — |
| Arch's Glass INC | Caitlin Marie Stewart-Baker | — | (707) 795 6976 | Windows, patio, painters | Rohnert Park · Sonoma County | — | — |
| Arciga Tile INC | Miguel Arciga | arciga.tile@gmail.com | (707) 536 5802 | Other | Santa Rosa · Sonoma County | — | — |
| Arcworks LLC | David Wayne Tippey | — | (707) 416 5131 | Electricians | Santa Rosa · Sonoma County | — | — |
| Ardillo's Tree Service LLC | Ruben Ruiz Ruiz | — | (707) 322 6281 | Tree | Santa Rosa · Sonoma County | — | — |
| Arellano Peerless Flooring INC | Razo Alvaro Arellano | — | (707) 890 0891 | Other | Santa Rosa · Sonoma County | — | — |
| Argenalwelding INC | Jose Manuel Argenal | — | (707) 765 5993 | Other | Penngrove · Sonoma County | — | — |
| Argonaut Constructors INC | Michael Anthony Smith | info@argonautconstructors.com | (707) 542 4862 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| Ari Wangerin | Ari Wangerin | — | (510) 552 4770 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| Ariel Berglund Plumbing | Ariel Berglund Plumbing | — | (530) 282 2656 | Other | Petaluma · Sonoma County | — | — |
| Arietta Electric LLC | Daniel Joseph Arietta | ariettaelectric@gmail.com | (707) 338 6473 | Electricians | Santa Rosa · Sonoma County | — | — |
| Aristocrat Wood Products Co | Zachary Joseph Correia | — | (707) 431 0264 | Other | Cloverdale · Sonoma County | — | — |