| 1 Aircare HVAC | Hrek Oleksandr | — | (209) 281 5663 | HVAC | Oakdale · Stanislaus County | — | — |
| 108 Mechanical | 108 Mechanical | — | (209) 648 2371 | HVAC | Knights Ferry · Stanislaus County | — | — |
| 1st Choice Electric Enterprises INC | Marcos Antonio Vazquez | — | (209) 809 5021 | Electricians | Modesto · Stanislaus County | — | — |
| 1st Class Construction INC | Troy Anthony Ross | — | (209) 617 8452 | GC, remodel, ADU | Patterson · Stanislaus County | — | — |
| 1st Security & Sound | Robert Tracey Wright | — | (209) 522 6180 | Electricians | Modesto · Stanislaus County | — | — |
| 209 Pavement | Elizabeth Marie Vanderveen | — | (209) 985 9581 | GC, remodel, ADU | Modesto · Stanislaus County | — | — |
| 24/7 Builders INC | Jose Manuel Gomez | — | (510) 875 4582 | GC, remodel, ADU | Patterson · Stanislaus County | — | — |
| 24/7 Day Electrical | Thomas Charles Iii Day | — | (209) 535 2094 | Electricians | Waterford · Stanislaus County | — | — |
| 3 - D Painting | Dale Leedy Denlinger | — | (209) 872 6919 | Windows, patio, painters | Modesto · Stanislaus County | — | — |
| 3 C's Ornamental Iron Works | Javier Valencia Chavez | — | (408) 225 4100 | Other | Waterford · Stanislaus County | — | — |
| 3 D Green Plumbing | 3 D Green Plumbing | — | (209) 808 6807 | Other | Modesto · Stanislaus County | — | — |
| 3 Diamonds Construction INC | Juan Antonio Santoyo Lopez | — | (408) 648 6178 | GC, remodel, ADU | Modesto · Stanislaus County | — | — |
| 3 Elements Heating & Cooling INC | Paul Samuel Mcgill | — | (209) 202 1000 | HVAC | Newman · Stanislaus County | — | — |
| 360 Waterproofing Services | Barrera Bustos Samuel | — | (408) 648 3779 | Other | Patterson · Stanislaus County | — | — |
| 3D Door Designs | 3D Door Designs | — | (209) 879 9153 | Other | Riverbank · Stanislaus County | — | — |
| 3G Flooring Solutions | 3G Flooring Solutions | — | (209) 252 2100 | Other | Crows Landing · Stanislaus County | — | — |
| 4 Ace Tile | 4 Ace Tile | — | (209) 522 2453 | Other | Modesto · Stanislaus County | — | — |
| 4 Vanz4 Build & D3sign | 4 Vanz4 Build & D3sign | — | (209) 204 8841 | GC, remodel, ADU | Modesto · Stanislaus County | — | — |
| 5 Star Pool Plaster INC | Luz Maria Munoz | — | (925) 606 1812 | Pool | Modesto · Stanislaus County | — | — |
| 7 Contractors | Rafael Idos Angeles | — | (209) 996 8746 | GC, remodel, ADU | Modesto · Stanislaus County | — | — |
| 7/11 Materials INC | Deanna Antonette Renteria | — | (209) 521 9771 | Other | Modesto · Stanislaus County | — | — |
| 8 A Insulation Co | Ochoa Jaime | — | (209) 968 8024 | Other | Ceres · Stanislaus County | — | — |
| 8A Stone & Tile Surfaces | 8A Stone & Tile Surfaces | — | (209) 289 7657 | Other | Modesto · Stanislaus County | — | — |
| 91 Plumbing Company | James Lewis Jr Bolin | — | (209) 552 5209 | Other | Modesto · Stanislaus County | — | — |
| A & A Landscaping Co | Armando Jr Rodriguez | — | (209) 410 9562 | Windows, patio, painters | Riverbank · Stanislaus County | — | — |
| A & E Construction & Remodeling INC | Alan Jay Boyington | — | (209) 252 9837 | GC, remodel, ADU | Turlock · Stanislaus County | — | — |
| A & J Construction INC | Juan Eduardo Farias | — | (209) 801 6574 | GC, remodel, ADU | Ceres · Stanislaus County | — | — |
| A & J Flooring | Jafet Conrado Cruz Garcia | info@ajflooring.com | (209) 985 1205 | Other | Modesto · Stanislaus County | — | — |
| A & J Velazquez Landscaping INC | Jose Antonio Velazquez | — | (209) 534 5717 | Windows, patio, painters | Modesto · Stanislaus County | — | — |
| A & R Concrete INC | Oscar Ruben Ahumada | — | (209) 604 0027 | Other | Modesto · Stanislaus County | — | — |
| A & S Home Improvement | A & S Home Improvement | — | (805) 844 6927 | GC, remodel, ADU | Turlock · Stanislaus County | — | — |
| A - 1 Glass Co | Debra Lynne Stafford | — | (209) 522 1172 | GC, remodel, ADU | Modesto · Stanislaus County | — | — |
| A - Quality Painting | A - Quality Painting | wweeiihhuuaanngg@gmail.com | (209) 566 5351 | Windows, patio, painters | Modesto · Stanislaus County | — | — |
| A - Team Electric | Tynda Aleksandr | — | (209) 918 3320 | Electricians | Hughson · Stanislaus County | — | — |
| A 2 Z Construction & Maintenance LLC | Stoney Sparky Mccullough | — | (209) 496 7735 | GC, remodel, ADU | Modesto · Stanislaus County | — | — |
| A 2 Z Garage Doors | A 2 Z Garage Doors | — | (209) 652 2686 | Other | Modesto · Stanislaus County | — | — |
| A A E Construction INC | Juan Antonio Burgos Favela | — | (209) 408 9133 | GC, remodel, ADU | Ceres · Stanislaus County | — | — |
| A A E S INC | Atif Ahmad Ammar | — | (209) 601 0038 | Electricians | Riverbank · Stanislaus County | — | — |
| A A Guaranteed Electric | Jacob Capril Aaron | — | (209) 281 7600 | Electricians | Ceres · Stanislaus County | — | — |
| A And P Construction | Pourtaverdi Albert | — | (209) 648 4319 | GC, remodel, ADU | Turlock · Stanislaus County | — | — |