| Shelton Lee Flooring Specialties INC | Tom Oan Mathews | — | (259) 491 0310 | Other | Modesto · Stanislaus County | — | — |
| Shep Welding Fabrication | Zachary Eli Shepherd | — | (209) 840 2753 | HVAC | Oakdale · Stanislaus County | — | — |
| Shields Glass | Shields Glass | — | (209) 668 7031 | Windows, patio, painters | Turlock · Stanislaus County | — | — |
| Shutter Elite | Shutter Elite | — | (209) 604-2488 | Other | Turlock · Stanislaus County | — | — |
| Siemion Construction | Jason Robert Siemion | — | (209) 840 9836 | GC, remodel, ADU | Modesto · Stanislaus County | — | — |
| Sierra Casework INC | Shawn Aaron Cheney | — | (209) 527 5729 | Other | Modesto · Stanislaus County | — | — |
| Sierra Coast Construction INC | Alexander Ricardo Gonzalez | — | (209) 638 6905 | GC, remodel, ADU | Denair · Stanislaus County | — | — |
| Sierra Custom Construction | Mario Antone Mc Ghee | — | (209) 524 2935 | GC, remodel, ADU | Modesto · Stanislaus County | — | — |
| Sierra Enterprise | Sierra Enterprise | — | (209) 847 4090 | GC, remodel, ADU | Oakdale · Stanislaus County | — | — |
| Sign Designs INC | Douglas Lundin Smith | sdi@signdesigns.com | (209) 524 4484 | GC, remodel, ADU | Modesto · Stanislaus County | — | — |
| Signature Construction | Michael Alan Hayes | contactus@signatureconstruction.com | (209) 480 6959 | GC, remodel, ADU | Modesto · Stanislaus County | — | — |
| Signature Signs | Michael Scott Gibson | — | (209) 848 8880 | Other | Oakdale · Stanislaus County | — | — |
| Signs By Randy | Signs By Randy | — | (209) 848 0330 | Other | Oakdale · Stanislaus County | — | — |
| Silman Construction | Bryce Jason Silman | — | (209) 596 6032 | GC, remodel, ADU | Patterson · Stanislaus County | — | — |
| Silva Old School Tile Setter INC | Arce Fermin Silva | — | (209) 809 8249 | Other | Patterson · Stanislaus County | — | — |
| Silva's Backhoe Service | Joseph Herman Jr Silva | — | (209) 495 9671 | Other | Turlock · Stanislaus County | — | — |
| Silver Flooring Services INC | Llerenas Anguiano Silverio | — | (209) 485 3747 | GC, remodel, ADU | Oakdale · Stanislaus County | — | — |
| Silver S Construction | Mendez Saul Zamora | — | (209) 605 1521 | GC, remodel, ADU | Modesto · Stanislaus County | — | — |
| Simile Construction Service INC | Joseph John Simile | — | (209) 545 6111 | GC, remodel, ADU | Modesto · Stanislaus County | — | — |
| Simmons And Sons Flooring | Terry Jr Simmons | — | (661) 333 7479 | Other | Modesto · Stanislaus County | — | — |
| Simplexx Plumbing & Drain Cleaning | Simplexx Plumbing & Drain Cleaning | — | (209) 495 5087 | Other | Ceres · Stanislaus County | — | — |
| Simplisafe | Simplisafe | customer-support@simplisafe.co.uk | — | Alarm and generators | Modesto · Stanislaus County | — | — |
| Sin Cal Fencing | James Jason Jarman | — | (209) 479 1518 | Other | Modesto · Stanislaus County | — | — |
| Sinclair General Engineering Construction INC | Sean Charles Sinclair | — | (209) 847 6100 | GC, remodel, ADU | Oakdale · Stanislaus County | — | — |
| Singh's Welding | Singh's Welding | — | (209) 675 0198 | Other | Turlock · Stanislaus County | — | — |
| Singleton Landscaping INC | Charles Gerald Singleton | — | (209) 324 9421 | Windows, patio, painters | Hughson · Stanislaus County | — | — |
| Skipper Jeff Remodeling | Skipper Jeff Remodeling | — | (209) 541 5797 | GC, remodel, ADU | Patterson · Stanislaus County | — | — |
| Skipper Remodeling INC | Russell David Skipper | — | (209) 614 3592 | GC, remodel, ADU | Modesto · Stanislaus County | — | — |
| Sky Rooter & Plumbing INC | Jitendra Raj Singh | — | (209) 595 0532 | Other | Modesto · Stanislaus County | — | — |
| Sky Whirl INC | Joshua Naranjo | — | (209) 535 8086 | HVAC | Patterson · Stanislaus County | — | — |
| Skylines Roofing | Wandenna May Jackson | — | (209) 551 5722 | Other roofers | Modesto · Stanislaus County | — | — |
| Skyway Pools & Spas Landscape Contractor | Eduardo Delgado Cardenas | — | (209) 430 7593 | Windows, patio, painters | Modesto · Stanislaus County | — | — |
| Slade Electric INC | Emmanuel Wayne Slade | — | (209) 605 4906 | Electricians | Turlock · Stanislaus County | — | — |
| Smart Choice Construction INC | Eberardo Zamora | — | (650) 716 6734 | GC, remodel, ADU | Modesto · Stanislaus County | — | — |
| Smartscape Turf Innovations | Smartscape Turf Innovations | — | (209) 201 9754 | Other | Modesto · Stanislaus County | — | — |
| Smith Construction | Kenneth Eugene Smith | — | (209) 484 3082 | GC, remodel, ADU | Modesto · Stanislaus County | — | — |
| Smith Floor Covering | Smith Floor Covering | — | (209) 540 2880 | Other | Oakdale · Stanislaus County | — | — |
| Snow Tile LLC | Jake Henry Snow | — | (209) 417 8642 | Other | Waterford · Stanislaus County | — | — |
| Sns Painting | Sns Painting | — | (209) 401 5903 | Windows, patio, painters | Modesto · Stanislaus County | — | — |
| Soar Building | Soar Building | — | (209) 202 6564 | GC, remodel, ADU | Turlock · Stanislaus County | — | — |