| Rock And Sons INC | Alexis Levi Emmerson | enq@rocksons.com | (707) 965 2889 | Electricians | Angwin · Napa County | — | — |
| Rojas Painting | Rojas Painting | rojaspainting@gmail.com | (707) 799 6104 | Windows, patio, painters | Napa · Napa County | — | — |
| Roland B Friedrich Construction | Roland Bruce Friedrich | — | (707) 326 3634 | GC, remodel, ADU | Deer Park · Napa County | — | — |
| Roll Out Electric | Jose Antonio Rodriguez | — | (707) 694 4571 | Electricians | Napa · Napa County | — | — |
| Ron M Walker Construction | Ronald M Walker | — | (707) 249 5679 | GC, remodel, ADU | Napa · Napa County | — | — |
| Ron Priest Construction INC | Ronald Leroy Priest | rtpriest@usa.net | (707) 732 8000 | GC, remodel, ADU | Angwin · Napa County | — | — |
| Ron Spiteri | Ron Spiteri | — | (707) 338 5195 | Other | Napa · Napa County | — | — |
| Ronald E Cox Designer / Builder INC | Ronald Eugene Cox | — | (707) 396 9051 | GC, remodel, ADU | Napa · Napa County | — | — |
| Rong's Backhoe Service | James Lee Rong | — | (707) 226 9412 | Other | Napa · Napa County | — | — |
| Roof INC | Amanda Lin Proctor | — | (707) 299 7103 | Other roofers | Napa · Napa County | — | — |
| Roots Strong Builder | Sebastian Balmore Hernandez | — | (415) 748 7538 | GC, remodel, ADU | Napa · Napa County | — | — |
| Rootstock Development | Steven David Kolos | — | (415) 518 2458 | GC, remodel, ADU | Napa · Napa County | — | — |
| Rosales Landscaping | Campos Rosas Pedro | — | (707) 738 1746 | Windows, patio, painters | Napa · Napa County | — | — |
| Roscoe INC | Brant Aaron Roscoe | firstname@roscoe.com | (707) 815 5900 | GC, remodel, ADU | Napa · Napa County | — | — |
| Rose General Contracting INC | Daniel Ray Rose | — | (707) 721 5874 | GC, remodel, ADU | Napa · Napa County | — | — |
| Rossi Plumbing | Rossi Plumbing | — | (707) 337 8124 | Other | Napa · Napa County | — | — |
| Rossi Residential Construction INC | Joseph Jr Rossi | — | (707) 257 6774 | GC, remodel, ADU | Napa · Napa County | — | — |
| Roy J Shaw INC DBA Shaw Plumbing | James Spencer Benjamin | — | (707) 942 6754 | Other | Calistoga · Napa County | — | — |
| Ruben Leija - General Building Contractor | Ruben Hernandez Leija | — | (707) 363 1581 | GC, remodel, ADU | Rutherford · Napa County | — | — |
| Ruiz Electric INC | Ruiz-maravilla Bryan | ruizeleectric17@yahoo.com | (707) 363 0301 | Electricians | Yountville · Napa County | — | — |
| Ruiz Roofing | Thomas Frederick Vance | — | (707) 819 2945 | Other roofers | Napa · Napa County | — | — |
| Ryan Brown Construction | Ryan Andrew Brown | — | (707) 637 6404 | GC, remodel, ADU | Napa · Napa County | — | — |
| Ryan Faller | Ryan Faller | — | (707) 815 0328 | Other | Napa · Napa County | — | — |
| Ryans Painting INC | Sylvester Ray Ryan | — | (707) 320 3561 | Windows, patio, painters | Napa · Napa County | — | — |
| S C Construction | Steven Paul Council | — | (707) 738 8485 | GC, remodel, ADU | Napa · Napa County | — | — |
| S C K Builders INC | John Martin O'donoghue | — | (650) 504 2632 | GC, remodel, ADU | Calistoga · Napa County | — | — |
| S E Lab Group INC | Jerry Robinson Orr | — | (707) 253 8852 | Other | Napa · Napa County | — | — |
| S G Construction | Gonzalez Saul | — | (707) 337 4156 | GC, remodel, ADU | St Helena · Napa County | — | — |
| S G M Construction Incorporated | Steven Gene Madison | — | (916) 807 4540 | GC, remodel, ADU | Yountville · Napa County | — | — |
| S Mendez INC | Mendez Salvador | — | (707) 815 9301 | Windows, patio, painters | Napa · Napa County | — | — |
| S S S Builders Corporation | Sandoval Salvador Saucedo | — | (707) 207 1216 | GC, remodel, ADU | American Canyon · Napa County | — | — |
| Safety Traffic And Resources | Safety Traffic And Resources | — | (510) 326 5505 | GC, remodel, ADU | Napa · Napa County | — | — |
| Sakai General Engineering INC | Bruce Jon Sakai | — | (707) 942 0578 | Other | Calistoga · Napa County | — | — |
| Sakai Landscaping & Irrigation INC | Wesley Yoshito Sakai | — | (707) 942 8933 | Windows, patio, painters | Calistoga · Napa County | — | — |
| Sam Cowell | Sam Cowell | sam.cowell@students.lsa.ac.uk | (707) 738 1842 | Other | Napa · Napa County | — | — |
| Sansan Landscaping | Sansan Landscaping | — | (707) 975 5785 | Windows, patio, painters | Napa · Napa County | — | — |
| Sanshine Landscaping | Sanshine Landscaping | — | (707) 342 1088 | Windows, patio, painters | Napa · Napa County | — | — |
| Santillan Stone And Tile INC | Guillermo Ramon Santillan-sigala | — | (707) 654 6888 | Other | Napa · Napa County | — | — |
| Saul's Painting | Saul's Painting | saul-rodriguez6@icloud.com | (707) 907 0194 | Windows, patio, painters | Calistoga · Napa County | — | — |
| Sax And Roscoe Construction INC | Brandon Keith Sax | — | (707) 815 4062 | GC, remodel, ADU | Napa · Napa County | — | — |