| Spontaneous Construction | Sean Edward Herman | — | (707) 758 8010 | GC, remodel, ADU | Sebastopol · Sonoma County | — | — |
| Spotless Plumbing | Robert Garfield Cottam | — | (855) 693 7246 | Other | Sonoma · Sonoma County | — | — |
| Spurgeon Painting INC | Thomas Boyd Meacham | — | (707) 763 7185 | Windows, patio, painters | Petaluma · Sonoma County | — | — |
| Spye Conservation Incorporated | Stephen Casey Pye | — | (707) 666 5550 | Windows, patio, painters | Petaluma · Sonoma County | — | — |
| Spyrka Electric INC | Scott Michael Spyrka | — | (707) 823 2986 | Electricians | Sebastopol · Sonoma County | — | — |
| Sr Construction | Rebentisch Sasha | — | (707) 495 4556 | GC, remodel, ADU | Guerneville · Sonoma County | — | — |
| Sr Custom Concrete | Sr Custom Concrete | — | (707) 495 2312 | Other | Santa Rosa · Sonoma County | — | — |
| Srt Forestry INC | Downing Cervantes Benjamin | ben@srtforestry.com | (707) 975 5882 | Tree | Santa Rosa · Sonoma County | — | — |
| St Francis Flooring INC | Kerry Brown | — | (707) 539 4790 | Other | Santa Rosa · Sonoma County | — | — |
| Stagecoach Development Co INC | Daniel Gene Bauman | — | (707) 528 8635 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| Staggs Electric | Timothy George Staggs | — | (707) 861 3421 | Electricians | Sebastopol · Sonoma County | — | — |
| Standout Stays | Standout Stays | — | (707) 395-6400 | Property managers | Sonoma · Sonoma County | — | — |
| Stanley Nicholas Grgich | Stanley Nicholas Grgich | — | (415) 308 0799 | GC, remodel, ADU | Sonoma · Sonoma County | — | — |
| Stansfield Fabrication | Stansfield Fabrication | — | (707) 364 4712 | Other | Rohnert Park · Sonoma County | — | — |
| Stapp's Fine Woodworking | Stapp's Fine Woodworking | stappy@comcast.net | (707) 994 9225 | Other | Rohnert Park · Sonoma County | — | — |
| Stat Heating & Air Corporation | David Alfred Andrews | — | (707) 755 0518 | HVAC | Petaluma · Sonoma County | — | — |
| Stately Construction | Christopher Raymond Stately | — | (707) 235 2024 | GC, remodel, ADU | Sonoma · Sonoma County | — | — |
| Steele Construction | Richard Dugald Steele | anapbm@gmail.com | (707) 484 6299 | Electricians | Santa Rosa · Sonoma County | — | — |
| Steele Electric | Christopher Paul Steele | — | (707) 318 4917 | Electricians | Santa Rosa · Sonoma County | — | — |
| Steffan Smith Construction | Steffan Aaron Smith | — | (916) 206 4944 | GC, remodel, ADU | Sonoma · Sonoma County | — | — |
| Stephen Andrew Black DBA Paint It Black | Paint It Black | — | (707) 799 4820 | Windows, patio, painters | Cotati · Sonoma County | — | — |
| Stephen Curley Roofing INC | Stephen Curley Roofing INC | — | (707) 546 4778 | Other roofers | Santa Rosa · Sonoma County | — | — |
| Stephen J Marcussen | Stephen J Marcussen | — | (707) 326 3889 | Other | Santa Rosa · Sonoma County | — | — |
| Stephen Marshall Cabinetmaker | Stephen Marshall Cabinetmaker | — | (415) 233 0423 | GC, remodel, ADU | Petaluma · Sonoma County | — | — |
| Stephens Properties INC | Charles Robert Stephens | — | (707) 763 6819 | GC, remodel, ADU | Petaluma · Sonoma County | — | — |
| Sterling Roofing Co INC | Jeremy James Jagdfeld | — | (707) 495 4161 | Other roofers | Glen Ellen · Sonoma County | — | — |
| Sterling Roofing's Co | Sterling Roofing's Co | — | (864) 340-5063 | Other roofers | Sonoma · Sonoma County | — | — |
| Steve C Burlington | Steve C Burlington | — | (707) 974 2257 | Electricians | Sonoma · Sonoma County | — | — |
| Steve Clark | Steve Clark | — | (415) 716 4362 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| Steve Eric Davis | Steve Eric Davis | — | (707) 695 9913 | Other | Rohnert Park · Sonoma County | — | — |
| Steve Janney Roofing INC | Steven Haines Janney | — | (415) 258 9676 | Other roofers | Penngrove · Sonoma County | — | — |
| Steve Lanning Construction INC | Steven Dean Lanning | — | (707) 938 1232 | GC, remodel, ADU | Sonoma · Sonoma County | — | — |
| Steve Lawrence Construction | Stephen Lanphier Lawrence | — | (707) 867 9909 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| Steve Logan Construction INC | Steven John Logan | — | (415) 255 5480 | GC, remodel, ADU | Sonoma · Sonoma County | — | — |
| Steve Martin Associates INC | Steven Michael Martin | — | (707) 824 9730 | GC, remodel, ADU | Sebastopol · Sonoma County | — | — |
| Steve Milton Construction | Steve Lee Milton | — | (707) 235 6318 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| Steve Murray Builders | Steve Murray Builders | — | (707) 431 7141 | GC, remodel, ADU | Healdsburg · Sonoma County | — | — |
| Steve Rogers Electric Incorporated | Steven Patrick Rogers | — | (707) 480 4991 | Electricians | Kenwood · Sonoma County | — | — |
| Steve Shook Construction | Steven Martin Shook | — | (707) 974 3362 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| Steve Thomas General Contractor | Steve Thomas General Contractor | — | (707) 479 1767 | GC, remodel, ADU | Sebastopol · Sonoma County | — | — |