| Irrigation Systems Management | Christine Theresa Colasurdo | — | (714) 925 3354 | Windows, patio, painters | Perris · Riverside County | — | — |
| Irriscape Construction INC | Robert Henking Smith | info@irriscapeconstruction.com | (951) 694 6936 | Windows, patio, painters | Temecula · Riverside County | — | — |
| Irvine Pipeline Company INC | Theresa Lee Brisco | — | (951) 351 1774 | Other | Riverside · Riverside County | — | — |
| Irvine Window Coverings LLC | Brandon Craig Green | — | (714) 350 7156 | Other | Corona · Riverside County | — | — |
| Irwin Electric | Kyle Patrick Irwin | — | (951) 765 7512 | Electricians | Banning · Riverside County | — | — |
| Isaac Hernandez | Isaac Hernandez | — | (951) 281 9644 | Windows, patio, painters | Corona · Riverside County | — | — |
| Isal Construction | Saldana Ornelas Ivan | — | (951) 375 7529 | Electricians | Winchester · Riverside County | — | — |
| Ishine Cleaning | Ishine Cleaning | — | (714) 333 5799 | Other | Norco · Riverside County | — | — |
| Isl Construction | Oros Ioan | — | (714) 400 8399 | GC, remodel, ADU | Corona · Riverside County | — | — |
| Island Hometech INC | Lawrence Lee Merrill | — | (951) 837 9434 | Other | Temecula · Riverside County | — | — |
| Island Patio Covers | Sadara Tyrone Ongalibang | — | (951) 232 5804 | GC, remodel, ADU | Norco · Riverside County | — | — |
| Islas Construction Service | Juan Manuel Islas | — | (714) 609 1514 | GC, remodel, ADU | Riverside · Riverside County | — | — |
| Islas Heating & Cooling | Jose Alfredo Islas Lopez | — | (415) 755 5426 | HVAC | Menifee · Riverside County | — | — |
| Islas Pools INC | Abraham Islas | — | (760) 272 5475 | Pool | Cathedral City · Riverside County | — | — |
| Ismael & Ismael Jr Painting | Ismael Sr Camarillo | — | (760) 669 6420 | Windows, patio, painters | Corona · Riverside County | — | — |
| Israel Bautista | Israel Bautista | — | (951) 796 3205 | GC, remodel, ADU | Murrieta · Riverside County | — | — |
| Israel Fernando Montes De Oca | Israel Fernando Montes De Oca | — | (760) 409 9237 | GC, remodel, ADU | Cathedral City · Riverside County | — | — |
| Israel Morgan | Israel Morgan | — | (760) 485 3025 | GC, remodel, ADU | Coachella · Riverside County | — | — |
| Issa Electric | Juan Manuel Sanchez | — | (909) 772 0216 | Electricians | Riverside · Riverside County | — | — |
| Issa Electric INC | Juan Manuel Sanchez | — | (909) 772 0216 | Electricians | Riverside · Riverside County | — | — |
| It's No Sweat Heat & Air | Justin James Jaszewski | — | (951) 545 8960 | HVAC | Moreno Valley · Riverside County | — | — |
| Ital-tile-design INC | Rini Luigi | — | (951) 704 6232 | Other | Winchester · Riverside County | — | — |
| Italian Construction INC | Paul Trader | — | (951) 296 9510 | GC, remodel, ADU | Temecula · Riverside County | — | — |
| Itani Design Concepts | Itani Design Concepts | — | (661) 549 5886 | GC, remodel, ADU | Corona · Riverside County | — | — |
| Itc Construction Services | Kyle Robert Bailes | — | (949) 491 4144 | Electricians | Riverside · Riverside County | — | — |
| Itech California | Timothy Richard Hieter | sales@itechca.us | (855) 994 8324 | Electricians | Menifee · Riverside County | — | — |
| Ivan Esparza | Ivan Esparza | — | (951) 410 1820 | GC, remodel, ADU | Riverside · Riverside County | — | — |
| Ivan Grablev | Ivan Grablev | — | (805) 689 3096 | GC, remodel, ADU | Riverside · Riverside County | — | — |
| Ivan's Blinds And More | Ivan Gary Samuels | — | (760) 777 7670 | Other | La Quinta · Riverside County | — | — |
| Ivan's Garage Doors | Ivan's Garage Doors | — | (760) 799 2645 | Other | Hemet · Riverside County | — | — |
| Ivan's Painting INC | Raul Ivan Castillo | — | (760) 507 9980 | GC, remodel, ADU | Coachella · Riverside County | — | — |
| Ivanov Milen Genov DBA Home Plumbing Co | Ivanov Milen Genov | — | (951) 310 2786 | Other | Menifee · Riverside County | — | — |
| Ivv Painting INC | Jeff Valdez-Sanchez | — | (760) 275 1376 | Windows, patio, painters | Desert Hot Springs · Riverside County | — | — |
| Iw Design LLC DBA Iw Design And Construction | Stephan Stephanoff | — | (442) 666 4508 | GC, remodel, ADU | Indian Wells · Riverside County | — | — |
| Iwatcher Plus | Oscar Jin Zhang | iwatcherplus@gmail.com | (951) 377 3315 | HVAC | Riverside · Riverside County | — | — |
| Iwatcher Plus Security Solutions | Iwatcher Plus Security Solutions | — | (951) 643-2080 | Alarm and generators | Riverside · Riverside County | — | — |
| Iz Finishes Tile And Granite | Iz Finishes Tile And Granite | — | (442) 342 5549 | Other | Palm Springs · Riverside County | — | — |
| J & A Home Improvements | Jose De Jesus Alcala Cervantes | info@jahomeimprovements.com | (562) 479 6849 | GC, remodel, ADU | Moreno Valley · Riverside County | — | — |
| J & A Installations INC | Cervantes Javier | — | (714) 334 7524 | GC, remodel, ADU | Moreno Valley · Riverside County | — | — |
| J & A Plumbing & Drain Solutions LLC | Francisco Antonio Gonzalez Garcia | — | (760) 504 4139 | Other | Hemet · Riverside County | — | — |