| Rubicon Landscape | Eric David Hage | danielh@rubiconprograms.org | (510) 231 4400 | Windows, patio, painters | Richmond · Contra Costa County | — | — |
| Rubicon Landscape Corporation | James Allen Miranda | danielh@rubiconprograms.org | (510) 221 4400 | Windows, patio, painters | Richmond · Contra Costa County | — | — |
| Rubio Acoustical Interiors | Rubio Acoustical Interiors | — | (925) 550 5560 | Other | Brentwood · Contra Costa County | — | — |
| Rubio's Concrete | Rubio's Concrete | — | (925) 698 2058 | Other | Antioch · Contra Costa County | — | — |
| Rubio's Construction | Rubio Porfirio | — | (925) 708 3192 | GC, remodel, ADU | Oakley · Contra Costa County | — | — |
| Rudy Fence INC | Rodolfo Javier Tejeda Prieto | — | (925) 586 2282 | Other | Concord · Contra Costa County | — | — |
| Rudy's Commercial Refrigeration INC | Bennie Lee Plant | — | (510) 234 9424 | HVAC | San Pablo · Contra Costa County | — | — |
| Rudy's Custom Concrete | Rudy's Custom Concrete | — | (925) 513 2183 | Other | Brentwood · Contra Costa County | — | — |
| Ruiz Electric | Luna Alfredo Ruiz | ruizeleectric17@yahoo.com | (510) 260 7225 | Electricians | Richmond · Contra Costa County | — | — |
| Ruiz Legacy Electric INC | Hernandez Hugo Ruiz | — | (925) 681 9648 | Electricians | Antioch · Contra Costa County | — | — |
| Ruiz Metal Fabricators INC | Andrey Ruiz | — | (510) 724 9335 | Other | Richmond · Contra Costa County | — | — |
| Russell Flood Electric | Russell William Flood | — | (925) 752 3702 | Electricians | Brentwood · Contra Costa County | — | — |
| Russo Environmental Services INC | Craig Anthony Joseph | — | (925) 432 1755 | Other | Pittsburg · Contra Costa County | — | — |
| Rvp Construction INC | Pereira Roberto Varela | — | (925) 325 5942 | GC, remodel, ADU | Pittsburg · Contra Costa County | — | — |
| Rwb Painting And Construction INC | Travis Jon Sumerlin | — | (925) 207 0552 | GC, remodel, ADU | Concord · Contra Costa County | — | — |
| Ryan Gilliam Construction | Ryan Lyle Gilliam | — | (510) 313 3684 | GC, remodel, ADU | El Sobrante · Contra Costa County | — | — |
| Ryan Loria Plumbing | Ryan Joseph Loria | — | (925) 681 8226 | Other | Concord · Contra Costa County | — | — |
| Ryan Perrypatton Eyges | Ryan Perrypatton Eyges | — | (510) 604 4260 | GC, remodel, ADU | Richmond · Contra Costa County | — | — |
| Ryder Homes Of California INC | Ned Jay Ryder | — | (925) 937 4373 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| Ryno's Garage Doors INC | Ryan Leo Mangante | — | (925) 565 6277 | Other | Oakley · Contra Costa County | — | — |
| Rytech Restoration Of Eastern Contra Costa County | Selvin Ronald Trigueros-Rivera | — | (925) 804 1054 | GC, remodel, ADU | Pittsburg · Contra Costa County | — | — |
| Rzr Plastering INC | Rudi Emerson Zavala Rogel | — | (925) 316 3362 | Other | Antioch · Contra Costa County | — | — |
| Rzs Steel LLC | Rodriguez Miguel | — | (510) 776 5350 | Other | El Sobrante · Contra Costa County | — | — |
| S & B Electric | Stewart Morey Jr Brown | — | (925) 332 5943 | Electricians | Concord · Contra Costa County | — | — |
| S & E Masters Painting & Decorating INC | Bjelogrlic Sava | — | (925) 818 6042 | Windows, patio, painters | Pleasant Hill · Contra Costa County | — | — |
| S & F Golden Tree Services Corporation | Rodriguez Ramon Gonzalez | — | (510) 932 3078 | Other | Richmond · Contra Costa County | — | — |
| S & H Construction INC | Harmeet Singh Anand | — | (510) 579 7382 | HVAC | Danville · Contra Costa County | — | — |
| S & H Plastering INC | Harmeet Singh Anand | — | (510) 579 7382 | Other | Danville · Contra Costa County | — | — |
| S & H Scaffolding Rentals INC | Harmeet Singh Anand | — | (510) 579 7382 | Other | Danville · Contra Costa County | — | — |
| S & J Properties Construction INC | James Craig Long | — | (925) 575 0227 | GC, remodel, ADU | Danville · Contra Costa County | — | — |
| S & K Nellis Painting INC | Deborah Jean Hansen | — | (925) 687 2233 | Windows, patio, painters | Concord · Contra Costa County | — | — |
| S A Heating & Air Conditioning | Samuel Sr Arguello | — | (925) 450 5989 | HVAC | Oakley · Contra Costa County | — | — |
| S A Heating And Air Conditioning | Jose Hugo Suarez | — | (925) 337 3633 | HVAC | San Ramon · Contra Costa County | — | — |
| S A R Builders | Arayik Sargsyan | — | (925) 451 2202 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| S And A Pacific Construction | Vera Lukas | — | (510) 932 1955 | Other | Richmond · Contra Costa County | — | — |
| S And L Remodeling And Design INC | Al Louis Mastroianni | — | (925) 849 4206 | GC, remodel, ADU | Walnut Creek · Contra Costa County | — | — |
| S Anderson | S Anderson | s.anderson@s-anderson.com | (510) 589 3650 | GC, remodel, ADU | San Ramon · Contra Costa County | — | — |
| S B C A Tree Consulting | Stephen Gerald Batchelder | — | (510) 787 3075 | Windows, patio, painters | Crockett · Contra Costa County | — | — |
| S B E Builders | S B E Builders | info@sbebuilders.com | (925) 634 6022 | GC, remodel, ADU | Discovery Bay · Contra Costa County | — | — |
| S B Painting INC | Bahary Shaul | — | (925) 305 8686 | Windows, patio, painters | Pleasant Hill · Contra Costa County | — | — |