| Supreme Painting INC | Alberto Garcia | — | (707) 708 6484 | Windows, patio, painters | Santa Rosa · Sonoma County | — | — |
| Surface Art Countertop | Michael Landon Mc Combs | — | (707) 431 7693 | Other | Healdsburg · Sonoma County | — | — |
| Surge Electric | Sergio Steven Quiroz | — | (707) 331 4827 | Electricians | Santa Rosa · Sonoma County | — | — |
| Surge Electric Service | Jacob Henry Johnson | — | (707) 694 8638 | Electricians | Windsor · Sonoma County | — | — |
| Surgeon Electric | Vincenzo Anthony Chambrone | — | (707) 596 0632 | Electricians | Santa Rosa · Sonoma County | — | — |
| Susan Cristler Painting And Finishing | Susan Cristler Painting And Finishing | — | (707) 953 2677 | Windows, patio, painters | Sebastopol · Sonoma County | — | — |
| Sustainable Living Builders INC | Jaime Soren Delgado Lopez | — | (707) 595 8500 | Other roofers | Sebastopol · Sonoma County | — | — |
| Sustainable Structures INC | Jacques Courtright Levy | info@sustainablestructures.com | (702) 823 2800 | Electricians | Sebastopol · Sonoma County | — | — |
| Sutter Roofing Systems INC | Jason Nicholas Sutter | cameron@sutterroofingsystems.com | (707) 338-1264 | Other roofers | Sebastopol · Sonoma County | — | — |
| Swain Builders | Swain Builders | — | (707) 795 4448 | GC, remodel, ADU | Penngrove · Sonoma County | — | — |
| Swan Plumbing INC | Swan George | — | (707) 575 5541 | Other | Santa Rosa · Sonoma County | — | — |
| Swan Pools - Sonoma Pool Builder | Swan Pools - Sonoma Pool Builder | — | (707) 934-4194 | Pool | Santa Rosa · Sonoma County | — | — |
| Swartz Construction | John William Swartz | — | (916) 761 1990 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| Sweeney Electrical Contracting | Matthew Donald Sweeney | — | (707) 570 5169 | Electricians | Healdsburg · Sonoma County | — | — |
| Sweep For Hire | Sweep For Hire | impallari@gmail.com | (707) 876 9868 | Other | Bodega · Sonoma County | — | — |
| Sweet Bee Painting INC | Miguel Angel Espinosa Cardenas | sweetbeepainting@gmail.com | (707) 495-9185 | Windows, patio, painters | Santa Rosa · Sonoma County | — | — |
| Sweet Home Drywall | Eduardo Rodriguez | — | (707) 870 4800 | Other | Santa Rosa · Sonoma County | — | — |
| Swi Co Construction INC | Michael Ryan Swicegood | — | (707) 395 4044 | GC, remodel, ADU | Healdsburg · Sonoma County | — | — |
| Swift Finishing Incorporated | Percy Robert Swift | — | (707) 763 1311 | Windows, patio, painters | Petaluma · Sonoma County | — | — |
| Swifthawk Construction INC | Blake Evan Allen | — | (707) 892 3110 | GC, remodel, ADU | Occidental · Sonoma County | — | — |
| Swilly Plastering & Stucco | Mc Fadden Sean | — | (415) 516 0533 | Other | Sonoma · Sonoma County | — | — |
| Symbios INC | Kevin Stephen Falkerson | walbrach@symbios.com | (707) 824 0314 | GC, remodel, ADU | Sebastopol · Sonoma County | — | — |
| Symbiosis Landscape Maintenance And Irrigation | Symbiosis Landscape Maintenance And Irrigation | — | (707) 755 0485 | Windows, patio, painters | Sebastopol · Sonoma County | — | — |
| Symphonic Finishing | Symphonic Finishing | hello@rfuenzalida.com | (415) 305 8112 | GC, remodel, ADU | Cloverdale · Sonoma County | — | — |
| Sync Systems INC | Michael Lawrence Camotta | — | (707) 799 9558 | Other | Santa Rosa · Sonoma County | — | — |
| Synergy Construction LLC | Andrew Alan Christopherson | — | (707) 360 6180 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| Szanyi Construction INC | John Keller Szanyi | — | (707) 318 0846 | GC, remodel, ADU | Sonoma · Sonoma County | — | — |
| T & G Medeiros INC DBA Tony Medeiros - Wacker And Sons | Antonio Joseph Medeiros | — | (707) 795 4848 | Other | Penngrove · Sonoma County | — | — |
| T & T Painting Co | T & T Painting Co | — | (707) 996-0229 | Windows, patio, painters | Sonoma · Sonoma County | — | — |
| T C Builder | T C Builder | — | (707) 486 9867 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| T C Castle Construction INC | Thomas Steven Castellino | — | (707) 527 9231 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| T C Construction | Thomas George Cass | — | (707) 548 5053 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| T C Steel | Thomas James Cleary | sales@tcsteel.com | (707) 773 2150 | Other | Petaluma · Sonoma County | — | — |
| T Dent Landscape Services | Tony Louis Jr Dent | — | (707) 631 2720 | Windows, patio, painters | Petaluma · Sonoma County | — | — |
| T F Electric | Thomas Malcolm Free | — | (707) 934 5095 | Electricians | Sonoma · Sonoma County | — | — |
| T L Brown Construction Services | Timothy William Brown | — | (707) 494 5509 | GC, remodel, ADU | Sebastopol · Sonoma County | — | — |
| T L C Construction Services | Anthony Jr Lazaro | — | (707) 328 8099 | GC, remodel, ADU | Rohnert Park · Sonoma County | — | — |
| T M K Builders INC | Thomas Melvin Kline | tom@tmkbuilders.com | (415) 686 1178 | GC, remodel, ADU | Penngrove · Sonoma County | — | — |
| T M Loyola Company | Teofanes Montoya Loyola | — | (707) 206 0332 | GC, remodel, ADU | Rohnert Park · Sonoma County | — | — |
| T Mc Farlin INC DBA Bay West Construction | Thomas Joseph Mc Farlin | — | (707) 217 4510 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |