| Acn Construction INC | Alexander Alvarez Perez | — | (951) 807 0085 | GC, remodel, ADU | Moreno Valley · Riverside County | — | — |
| Acomm Cabling INC | Sebastian Valentin Velasco | — | (562) 756 5392 | Other | Menifee · Riverside County | — | — |
| Acosta AC | Acosta AC | — | (951) 206 5910 | HVAC | Jurupa Valley · Riverside County | — | — |
| Acosta Construction | Acosta Raul | — | (760) 619 9630 | GC, remodel, ADU | Palm Desert · Riverside County | — | — |
| Acosta Mechanical INC | Jose Luis Acosta | — | (760) 404 9914 | HVAC | Palm Springs · Riverside County | — | — |
| Acosta Painting | Acosta Painting | — | (951) 616 4155 | Windows, patio, painters | Corona · Riverside County | — | — |
| Acoustic Removal Experts | Acoustic Removal Experts | — | (866) 981 3979 | GC, remodel, ADU | Corona · Riverside County | — | — |
| Acps Plumbing & Drains INC | John Dale Pea | — | (951) 772 3946 | Other | Murrieta · Riverside County | — | — |
| Acr Acoustical Systems | Acr Acoustical Systems | acracousticalsys@gmail.com | (714) 231 0388 | GC, remodel, ADU | Lake Elsinore · Riverside County | — | — |
| Acr Acoustical Systems INC DBA Acr Construction | Alberto C Ramos | — | (714) 231 0388 | GC, remodel, ADU | Lake Elsinore · Riverside County | — | — |
| Act 1 Construction INC | Donald Wayne Trenholm | — | (951) 735 1184 | GC, remodel, ADU | Norco · Riverside County | — | — |
| Action 1 Automated Gates | Todd Neal Thomas | — | (951) 552 5967 | Other | Riverside · Riverside County | — | — |
| Action Acoustics INC | Dejon Louis| Anderson De Jon Louis Anderson | — | (951) 237 8391 | GC, remodel, ADU | Corona · Riverside County | — | — |
| Action Air Conditioning Service | Derrick Levert Tucker | — | (951) 764 9829 | HVAC | Moreno Valley · Riverside County | — | — |
| Action Development | Action Development | — | (951) 737 8391 | GC, remodel, ADU | Corona · Riverside County | — | — |
| Action Door Controls INC | Richard Paul Mesa | — | (951) 784 0622 | Other | Riverside · Riverside County | — | — |
| Action Heating & A / C | Tom Leon Tucker | — | (951) 217 1411 | HVAC | Hemet · Riverside County | — | — |
| Action Property Services | Matthew Shidan Feres | — | (951) 393 8460 | GC, remodel, ADU | Riverside · Riverside County | — | — |
| Action Repair Service | Hisham Abder-rahim El-khatib | — | (951) 808 0207 | HVAC | Corona · Riverside County | — | — |
| Action Security Systems | Action Security Systems | — | (951) 852 5515 | Electricians | Temecula · Riverside County | — | — |
| Active Air Control INC | Spencer Kyle Kincaid | — | (951) 987 0416 | HVAC | Corona · Riverside County | — | — |
| Active Drilling & Pump Supply | Active Drilling & Pump Supply | — | (951) 926 1254 | Other | Hemet · Riverside County | — | — |
| Active Plumbing & Rooter INC | Scott Wesley Douglas | — | (800) 970 2577 | GC, remodel, ADU | Corona · Riverside County | — | — |
| Active Power Solutions | Active Power Solutions | — | (818) 661 8287 | Electricians | Temecula · Riverside County | — | — |
| Active Restoration Construction | Robert Frederick Guedea | — | (951) 833 7866 | GC, remodel, ADU | Corona · Riverside County | — | — |
| Active Sheet Metal INC | Clayton Robert Johnson | — | (951) 549 9711 | Other | Corona · Riverside County | — | — |
| Activeconcretecutting | Juan Martell Macias | — | (714) 709 9872 | Other | Lake Elsinore · Riverside County | — | — |
| Acunas Engineering INC | Jose Luis Acuna Davalos | — | (951) 261 4808 | Other | Mira Loma · Riverside County | — | — |
| Adair's Custom Floor Covering | Adair's Custom Floor Covering | — | (951) 543 5381 | Other | Riverside · Riverside County | — | — |
| Adam Electric Contractor INC | Mohamed Ibra Soliman Elkhouly | — | (951) 790 9602 | Electricians | Eastvale · Riverside County | — | — |
| Adam Hall | Adam Hall | — | (951) 538 2730 | GC, remodel, ADU | Moreno Valley · Riverside County | — | — |
| Adam Kunka Construction | Adam Ryan Kunka | — | (626) 806 5422 | GC, remodel, ADU | Norco · Riverside County | — | — |
| Adam Othman | Adam Othman | — | (714) 553 2030 | GC, remodel, ADU | Canyon Lake · Riverside County | — | — |
| Adam Rene Puentes | Adam Rene Puentes | — | (951) 240 6036 | Other | Murrieta · Riverside County | — | — |
| Adame Contracting INC | Leopoldo Vidales Adame | — | (951) 238 8243 | GC, remodel, ADU | Nuevo · Riverside County | — | — |
| Adame Landscape INC | Adame Rodolfo | info@adamelandscape.com | (951) 698 3090 | Windows, patio, painters | Murrieta · Riverside County | — | — |
| Adame Underground Drilling Services | Andrew Barajas Adame | — | (714) 486 8859 | Other | Corona · Riverside County | — | — |
| Adamik's American Plumbing Drain And Backflow | Jonathan Robert Adamik | — | (714) 483 1244 | Other | Lake Elsinore · Riverside County | — | — |
| Adams Electric | Jeffrey James Adams | — | (951) 306 7782 | Electricians | Idyllwild · Riverside County | — | — |
| Adams Landscaping INC | Marc Edward Adams | — | (951) 694 9787 | Windows, patio, painters | Murrieta · Riverside County | — | — |