| Sax Construction INC | Brandon Keith Sax | — | (707) 815 4062 | GC, remodel, ADU | Napa · Napa County | — | — |
| Sc Builder | Sc Builder | — | (408) 607 8565 | GC, remodel, ADU | Calistoga · Napa County | — | — |
| Scaffold Solutions INC | Charles William Meadows | — | (707) 561 7712 | Other | American Canyon · Napa County | — | — |
| Scheidecker Construction Company | Timothy Lee Scheidecker | — | (707) 252 7726 | GC, remodel, ADU | Napa · Napa County | — | — |
| Schiller Philippe-auguste | Schiller Philippe-auguste | — | (404) 518 3961 | GC, remodel, ADU | American Canyon · Napa County | — | — |
| Schoeps Painting | Schoeps Painting | — | (707) 968 1054 | Windows, patio, painters | Napa · Napa County | — | — |
| Scholl Construction | John Adrian Scholl | — | (707) 337 4366 | GC, remodel, ADU | Napa · Napa County | — | — |
| Scott Duncan Construction | Scott Allan Duncan | — | (707) 486 1264 | GC, remodel, ADU | Napa · Napa County | — | — |
| Scott Eberlin Construction | Scott Allen Eberlin | — | (707) 812 9168 | GC, remodel, ADU | Napa · Napa County | — | — |
| Scott William Murphy DBA L&s Murphy Electrical | Scott William Murphy | — | (707) 486 6209 | Electricians | Napa · Napa County | — | — |
| Scott's Painting | Scott's Painting | — | (707) 718 4194 | Windows, patio, painters | Napa · Napa County | — | — |
| Segno-grafiks LLC DBA Fastsigns American Canyon | Mark Nicholas Barber | — | (707) 552 0110 | Other | American Canyon · Napa County | — | — |
| Seth Dillon Construction | Seth Randall Dillon | — | (707) 287 3048 | GC, remodel, ADU | Angwin · Napa County | — | — |
| Sfi Mechanical INC | Susan Mareta Fairbanks | — | (707) 710 8415 | Other | Calistoga · Napa County | — | — |
| Shergill's Landscape | Shergill's Landscape | — | (707) 648 7955 | Windows, patio, painters | American Canyon · Napa County | — | — |
| Sherwood INC | Eric Joseph Sherwood | — | (707) 310 1230 | GC, remodel, ADU | Napa · Napa County | — | — |
| Shimmer Pool And Spa Service | Roger Antonio Mejia | — | (707) 256 9971 | Pool | Napa · Napa County | — | — |
| Signature Tree Solutions | Curtis Lee Fosnaugh | — | (707) 963 3333 | Tree | St Helena · Napa County | — | — |
| Silverado Electric LLC | Donald Albert Gomez | — | (707) 252 0450 | Electricians | Napa · Napa County | — | — |
| Silverado Plumbing | Silverado Plumbing | — | (707) 548 2777 | Other | Napa · Napa County | — | — |
| Silverado Plumbing INC DBA Mr Rooter Plumbing | Scott Allen Rossmiller | — | (707) 252 6578 | GC, remodel, ADU | Napa · Napa County | — | — |
| Skn Construction INC | Kevin Garrett Nickerson | info@sknconstruction.com | (707) 690 0111 | GC, remodel, ADU | Napa · Napa County | — | — |
| Skylark Landscaping INC | Daniel John| Sakai Dan John Sakai | skylarklandscaping@att.net | (707) 257 7328 | Windows, patio, painters | Napa · Napa County | — | — |
| Skyline Tree Solutions | Skyline Tree Solutions | — | (707) 229-1809 | Tree | Napa · Napa County | — | — |
| Skywood Landscaping | Skywood Landscaping | sales@skywoodlandscaping.com | (707) 774 5499 | GC, remodel, ADU | American Canyon · Napa County | — | — |
| Slarve Construction LLC | Alexander Rubin Slarve | ap@slarveconstruction.com | (707) 927 3624 | GC, remodel, ADU | Napa · Napa County | — | — |
| Slaybuilt Welding INC | Bryon Keith Slay | — | (707) 227 2580 | Other | Napa · Napa County | — | — |
| Slim Glass | Slim Glass | — | (510) 529 8437 | Windows, patio, painters | American Canyon · Napa County | — | — |
| Slp Construction INC | Saul Lopez | — | (707) 681 4691 | GC, remodel, ADU | Napa · Napa County | — | — |
| Smart Finish | Jesus Valderrama | — | (415) 728 2804 | GC, remodel, ADU | Napa · Napa County | — | — |
| Smith Mobile Homes | Smith Mobile Homes | — | (707) 333 9803 | Other | Napa · Napa County | — | — |
| Sol Rio Construction | Solorio Juan Carlos | — | (707) 235 8941 | GC, remodel, ADU | Napa · Napa County | — | — |
| Solano-Napa Jatc | Solano-Napa Jatc | — | (707) 251-0315 | Electricians | Napa · Napa County | — | — |
| Solivella Terra Landscaping | Solivella Terra Landscaping | — | (707) 738 1773 | Windows, patio, painters | Napa · Napa County | — | — |
| Sonoma Mountain Homes INC | Robert Bradley Branstad | — | (510) 334 2232 | GC, remodel, ADU | Calistoga · Napa County | — | — |
| Sonoma Paint Center | Sonoma Paint Center | — | (707) 996-6756 | Windows, patio, painters | Sonoma · Napa County | — | — |
| Southern Ca Home Inspections | Southern Ca Home Inspections | — | (951) 461-9769 | Inspectors | Murrieta · Napa County | — | — |
| Specialized Construction And Fabrication INC | Joseph Raymond Bates | — | (707) 254 9442 | GC, remodel, ADU | Napa · Napa County | — | — |
| Specialized Storage Solutions INC | Mark Patton Hiddleson | — | (707) 732 3892 | GC, remodel, ADU | Napa · Napa County | — | — |
| Spiro Dalageorgas DBA Spiro's Painting Services | Spiro Peter Dalageorgas | — | (707) 252 8493 | Windows, patio, painters | Napa · Napa County | — | — |