| Stunts Custom Construction INC | Michael Robert Costlow | — | (707) 620 0717 | GC, remodel, ADU | Windsor · Sonoma County | — | — |
| Styles Design | Styles Design | — | (707) 479 4161 | GC, remodel, ADU | Cloverdale · Sonoma County | — | — |
| Suarez Plastering INC | Jose Refugio Suarez | — | (707) 235 9084 | Other | Petaluma · Sonoma County | — | — |
| Sullivan Construction | Christian Gregory Sullivan | — | (707) 322 8473 | GC, remodel, ADU | Petaluma · Sonoma County | — | — |
| Sullivan Professional Construction INC | Benjamin Michael Sullivan | — | (415) 827 1374 | GC, remodel, ADU | Petaluma · Sonoma County | — | — |
| Suman Tile INC | Devin Michael Suman | — | (707) 484 2159 | Other | Santa Rosa · Sonoma County | — | — |
| Summit Electric INC | Yvonne Pearl Martin | sales@summit-electric.com | (707) 542 4773 | Electricians | Santa Rosa · Sonoma County | — | — |
| Summit Electronic Systems INC | Laurence William Dashiell | — | (707) 542 4773 | Electricians | Santa Rosa · Sonoma County | — | — |
| Summit General Engineering | Summit General Engineering | — | (707) 495 4859 | Other | Penngrove · Sonoma County | — | — |
| Summit Granite And Tile | Ryan Carl Lesky | — | (530) 277 5008 | Other | Occidental · Sonoma County | — | — |
| Summit Technology Group INC | Laurence William Dashiell | — | (707) 542 4773 | Electricians | Santa Rosa · Sonoma County | — | — |
| Summit Tree Care | Summit Tree Care | — | (707) 762 6719 | Tree | Petaluma · Sonoma County | — | — |
| Sun America Solar & Construction Co | Mark Paul Kirchen | — | (707) 364 5915 | Other roofers | Petaluma · Sonoma County | — | — |
| Sun Electric | Kevin Preston Nave | — | (415) 215 6241 | Electricians | Sebastopol · Sonoma County | — | — |
| Sun Painting | Sun Painting | — | (707) 509 9291 | Windows, patio, painters | Sonoma · Sonoma County | — | — |
| Sun Ray Energy Systems | Sun Ray Energy Systems | — | (707) 703 7670 | Electricians | Cotati · Sonoma County | — | — |
| Sunco Electric | Ronald Dean Van Stone | admin@admin.com | (707) 537 9544 | Electricians | Santa Rosa · Sonoma County | — | — |
| Suncoast Painting Co | Todd Jerl Hutchison | — | (707) 703 8697 | Windows, patio, painters | Santa Rosa · Sonoma County | — | — |
| Sundance Decorating & Painting | Sundance Decorating & Painting | — | (707) 837 3626 | Windows, patio, painters | Monte Rio · Sonoma County | — | — |
| Sundog-e Electric | Marshall Gilmore Jennings | — | (707) 978 0964 | Electricians | Guerneville · Sonoma County | — | — |
| Sundriver Construction LLC | Jack Edward Rogers | — | (510) 332 6481 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| Sunny Pool Service | Justin David Key | — | (707) 331 2844 | Pool | Santa Rosa · Sonoma County | — | — |
| Sunrise Homestead General Contractor | Nicholas Louis Maimone | — | (707) 331 5887 | GC, remodel, ADU | Occidental · Sonoma County | — | — |
| Sunset Coast Construction INC | Randy Gene Ullyott | — | (707) 490 9900 | GC, remodel, ADU | Healdsburg · Sonoma County | — | — |
| Sunset Construction | Larry Allen Crabtree | — | (707) 584 9520 | GC, remodel, ADU | Rohnert Park · Sonoma County | — | — |
| Sunset Pools | Sunset Pools | — | (707) 546 0646 | Pool | Windsor · Sonoma County | — | — |
| Sunset Screens & Shades | Sunset Screens & Shades | — | (707) 843 7068 | Other | Santa Rosa · Sonoma County | — | — |
| Sunshine Aquatics INC | George Louis Catelli | — | (707) 486 9013 | Pool | Windsor · Sonoma County | — | — |
| Sunshine Construction | Daniel Joseph Dortch | — | (707) 539 7094 | Other | Santa Rosa · Sonoma County | — | — |
| Sunshine Sean Electrical Renewable Energy Services | Sean Farshied Pouyamehr | — | (650) 544 0880 | Electricians | Petaluma · Sonoma County | — | — |
| Super Service Plumbing | Ralph Arthur Dexter | service@superserviceplumbing.com | (707) 575 1500 | Other | Santa Rosa · Sonoma County | — | — |
| Superior Building | Neil Francis Seelhoff | superiorbuildingsystems1@gmail.com | (707) 347 9502 | Electricians | Petaluma · Sonoma County | — | — |
| Superior Concrete | Superior Concrete | — | (562) 606 6315 | Other | Santa Rosa · Sonoma County | — | — |
| Superior Finish And Detail | Superior Finish And Detail | — | (707) 975 9523 | GC, remodel, ADU | Petaluma · Sonoma County | — | — |
| Superior Grading & Paving | Richard Anthony Golobe | — | (707) 331 2892 | Other | Sebastopol · Sonoma County | — | — |
| Superior Pools And Spas | Joseph William Bischel | — | (805) 947 9132 | GC, remodel, ADU | Santa Rosa Valley · Sonoma County | — | — |
| Superior Screens INC | Peter Ray Balchinas | — | (707) 996 6105 | Other | Sonoma · Sonoma County | — | — |
| Superior Seamless Gutter INC | Cory Gene Thomas | — | (707) 585 1580 | Other | Cotati · Sonoma County | — | — |
| Superior Straight Line Fencing | Superior Straight Line Fencing | — | (707) 843 0041 | Other | Santa Rosa · Sonoma County | — | — |
| Supreme Finish & Painting Co | Anderson Humberto Romero Alvarado | — | (707) 213 6004 | Windows, patio, painters | Santa Rosa · Sonoma County | — | — |