| Redwood Property Services LLC | Barry Roger Fullman | — | (707) 530 4530 | GC, remodel, ADU | Kelseyville · Lake County | — | — |
| Reed Homes | Reed Homes | — | (707) 303 5881 | GC, remodel, ADU | Lakeport · Lake County | — | — |
| Refined Painting & Decorating | Refined Painting & Decorating | — | (707) 206 1044 | Windows, patio, painters | Hidden Valley Lake · Lake County | — | — |
| Refrigeration Technology Incorporated | C Glen Marks | — | (707) 987 0500 | HVAC | Middletown · Lake County | — | — |
| Reliable Plumbing | Jarrod Allen Giannecchini | — | (707) 987 9447 | Other | Hidden Valley Lake · Lake County | — | — |
| Rfc Flooring INC | Omar Alfonso Rosales | — | (707) 495 4179 | Other | Middletown · Lake County | — | — |
| Rg Martin Construction INC | Robert Glenn Martin | — | (707) 291 0653 | GC, remodel, ADU | Middletown · Lake County | — | — |
| Rice Lake Construction Group | Rice Lake Construction Group | — | (218) 546-5519 | GC, remodel, ADU | Carlsbad · Lake County | — | — |
| Rick Rose Painting | Rick Rose Painting | — | (707) 349 4675 | Windows, patio, painters | Lakeport · Lake County | — | — |
| Rico Tree Service | Rico Martinez Gerardo | — | (707) 828 5007 | Tree | Kelseyville · Lake County | — | — |
| Rico's Cabinets | Rico's Cabinets | — | (707) 413 9349 | Other | Lakeport · Lake County | — | — |
| Right On Time Heating And Cooling | Justin Gregory Mccarty | rightontimehvac@gmail.com | (707) 367 1194 | HVAC | Clearlake · Lake County | — | — |
| River City Remodeling | River City Remodeling | — | (916) 335 1319 | GC, remodel, ADU | Lakeport · Lake County | — | — |
| Rivera Contracting | Rafael Tapia Rivera | — | (707) 350 3725 | GC, remodel, ADU | Clear Lake · Lake County | — | — |
| Rls Custom Carpentry LLC | Robert Lee Jr Schmetzer | rob.schmetzer@gmail.com | (707) 513 8722 | GC, remodel, ADU | Lucerne · Lake County | — | — |
| Robinson Rancheria General Engineering | Aaron Wayne Oliver | — | (707) 533 5038 | Other | Nice · Lake County | — | — |
| Rodney Silva | Rodney Silva | — | (707) 350 0563 | GC, remodel, ADU | Clearlake · Lake County | — | — |
| Roger Anthony Construction | Roger Leroy Anthony | — | (707) 344 5226 | GC, remodel, ADU | Hidden Valley Lake · Lake County | — | — |
| Ron Raffo Roofing | Ronald Anthony Raffo | ronrafforoofing@comcast.com | (707) 708 1147 | Other roofers | Hidden Valley Lake · Lake County | — | — |
| Ron Sugimoto Const | Ron Sugimoto Const | — | (707) 350 5374 | GC, remodel, ADU | Clearlake Oaks · Lake County | — | — |
| Rowser Construction | Aaron Douglas Rowser | — | (707) 481 3777 | GC, remodel, ADU | Middletown · Lake County | — | — |
| Rpc General Contracting INC | Rees Wilson Purcell | — | (707) 294 0661 | GC, remodel, ADU | Middletown · Lake County | — | — |
| Rubin Construction | Nathaneil Rain Rubin | — | (707) 349 7193 | GC, remodel, ADU | Nice · Lake County | — | — |
| Rubio Builders | Rubio Builders | — | (707) 849 6294 | GC, remodel, ADU | Hidden Valley Lake · Lake County | — | — |
| Running Springs Heating & Air | Running Springs Heating & Air | — | (707) 263 4938 | HVAC | Lakeport · Lake County | — | — |
| Rupp Tile & Stone | Rupp Tile & Stone | — | (707) 292 9955 | Other | Hidden Valley Lake · Lake County | — | — |
| Russell Andrew Wallar | Russell Andrew Wallar | — | (510) 825 5823 | GC, remodel, ADU | Lakeport · Lake County | — | — |
| Ryan Perez Plumbing | Ryan Perez Plumbing | ryanperezplumbing@gmail.com | (707) 294 8953 | Other | Middletown · Lake County | — | — |
| Ryan Villanueva Construction | Ryan David Villanueva | — | (707) 245 6855 | GC, remodel, ADU | Lakeport · Lake County | — | — |
| S J F Electric | Stephen John Fogel | — | (415) 645 3951 | Electricians | Kelseyville · Lake County | — | — |
| S T Rhoades And C&s Civil Jv | T Rhoades Construction Incorporated S | — | (707) 489 9599 | Other | Lakeport · Lake County | — | — |
| Salas Roofing | Michael Robert Salas | — | (707) 416 9055 | Other roofers | Upper Lake · Lake County | — | — |
| Saldivar Concrete INC | J Asuncion Saldivar | — | (707) 326 7513 | Other | Clearlake · Lake County | — | — |
| Salmina Construction INC | Michael Patrick Salmina | — | (707) 355 1958 | GC, remodel, ADU | Lower Lake · Lake County | — | — |
| Samuels Signature Builds | Samuels Signature Builds | — | (707) 349 5186 | GC, remodel, ADU | Lakeport · Lake County | — | — |
| Sanders Construction Company | Frederick William Sanders | — | (707) 994 6733 | Other | Clear Lake Park · Lake County | — | — |
| Sawdust Construction | Kenneth Martin Brown | — | (707) 245 5240 | GC, remodel, ADU | Upper Lake · Lake County | — | — |
| Schelter Construction | John David Schelhorn | johnschelhorn@gmail.com | (707) 396 2435 | GC, remodel, ADU | Hidden Valley Lake · Lake County | — | — |
| Scott Construction | Patrick William Jack Scott | general@scott-construction.com | (707) 994 3567 | GC, remodel, ADU | Clearlake · Lake County | — | — |
| Scott Marsh Drywall | Scott Marsh Drywall | — | (408) 455 1524 | Other | Kelseyville · Lake County | — | — |