| A-1 All Star Plumbing | A-1 All Star Plumbing | — | (559) 584 0476 | Other | Hanford · Kings County | — | — |
| A-1 American Plumbing Heating And Air Conditioning | David Michael Le May | — | (510) 581 0607 | HVAC | San Leandro · Alameda County | — | — |
| A-1 Andor Welding | Rogelio Lopez | — | (714) 337 1160 | Other | Hesperia · San Bernardino County | — | — |
| A-1 Anytime Construction | Andrew Douglas Whitehead | — | (661) 376 5737 | GC, remodel, ADU | Bakersfield · Kern County | — | — |
| A-1 Apache Plumbing | A-1 Apache Plumbing | — | (323) 385 8763 | GC, remodel, ADU | La Habra · Orange County | — | — |
| A-1 Asphalt | A-1 Asphalt | — | (408) 726 6188 | Other | Milpitas · Santa Clara County | — | — |
| A-1 Backhoe Service | Scott Douglas Hill | — | (408) 639 8453 | Other | Hollister · San Benito County | — | — |
| A-1 Bay Area Rooter & Plumbing | Matias Pablo Luis | — | (510) 712 0906 | Other | Oakland · Alameda County | — | — |
| A-1 Best Development Group | Hubert William Tsang | — | (626) 757 2225 | GC, remodel, ADU | Temple City · Los Angeles County | — | — |
| A-1 Builders General Contractors INC | Craig Brian Mason | — | (707) 570 2900 | GC, remodel, ADU | Santa Rosa · Sonoma County | — | — |
| A-1 California Builders | A-1 California Builders | — | (818) 222 1050 | GC, remodel, ADU | Calabasas · Los Angeles County | — | — |
| A-1 Comfort Heating & Air | A-1 Comfort Heating & Air | — | (707) 301 0717 | HVAC | Fairfield · Solano County | — | — |
| A-1 Complete Yard Service LLC | Autar Singh Johal | — | (925) 829 9650 | Windows, patio, painters | Dublin · Alameda County | — | — |
| A-1 Concrete INC | Mark David Simmons | — | (805) 712 5630 | Other | Atascadero · San Luis Obispo County | — | — |
| A-1 Concrete Pumping INC | Tim Shawn Regan | mattsmith@a1pumpcrete.com | (619) 206 7867 | Other | San Diego · San Diego County | — | — |
| A-1 Construction | Shane Darnell Scanlon | — | (818) 709 4341 | GC, remodel, ADU | Chatsworth · Los Angeles County | — | — |
| A-1 Construction | Thad James Henninger | — | (707) 350 1818 | GC, remodel, ADU | Lakeport · Lake County | — | — |
| A-1 Construction | John Edward Lindsay | — | (805) 525 6400 | GC, remodel, ADU | Santa Paula · Ventura County | — | — |
| A-1 Construction | Berg Rene | — | (619) 855 2677 | GC, remodel, ADU | Ocean Beach · San Diego County | — | — |
| A-1 Construction & Landscaping INC | Michael David Peryea | — | (951) 658 7434 | GC, remodel, ADU | Hemet · Riverside County | — | — |
| A-1 Construction & Management Co | Kwang Rock Chung | — | (408) 469 2628 | GC, remodel, ADU | Sunnyvale · Santa Clara County | — | — |
| A-1 Construction & Remodel | Jaspal Singh Klair | — | (559) 479 2566 | GC, remodel, ADU | Madera · Madera County | — | — |
| A-1 Construction Building Services INC | Antonio Garcia | — | (562) 370 5958 | GC, remodel, ADU | Long Beach · Los Angeles County | — | — |
| A-1 Construction Management | Mezain Omar El | — | (858) 345 0044 | GC, remodel, ADU | San Diego · San Diego County | — | — |
| A-1 Contracting LLC | Robert Davis Piddock | — | (510) 928 0027 | Other | Castro Valley · Alameda County | — | — |
| A-1 Creative Design General Contracting | Bradley Lyle Barnes | — | (818) 648 2544 | GC, remodel, ADU | Canoga Park · Los Angeles County | — | — |
| A-1 Custom Stone And Tile | A-1 Custom Stone And Tile | — | (562) 755 6167 | Other | Whittier · Los Angeles County | — | — |
| A-1 Deadbolt & Door | A-1 Deadbolt & Door | — | (831) 476 7970 | GC, remodel, ADU | Capitola · Santa Cruz County | — | — |
| A-1 Deck & Coating | A-1 Deck & Coating | — | (310) 560 0298 | Other | Torrance · Los Angeles County | — | — |
| A-1 Delivery Co | Michael Terry Webb | — | (909) 444 1220 | Other | Ontario · San Bernardino County | — | — |
| A-1 Demolition & Hauling | Alvarez Francisco Alvarez | — | (510) 472 4844 | Other | Hayward · Alameda County | — | — |
| A-1 Drains | A-1 Drains | — | (530) 598 2789 | Other | Etna · Siskiyou County | — | — |
| A-1 Drilling & Pump Service INC | Gurminder Singh Sandher | — | (530) 632 4373 | GC, remodel, ADU | Yuba City · Sutter County | — | — |
| A-1 Drywall | A-1 Drywall | — | (805) 340 9908 | Other | Ventura · Ventura County | — | — |
| A-1 Dynamic Builders INC | Jianguo Li | — | (415) 770 9736 | GC, remodel, ADU | San Francisco · San Francisco County | — | — |
| A-1 Electric | Jules Wathan Iv Pruitt | — | (909) 624 7578 | Electricians | Claremont · Los Angeles County | — | — |
| A-1 Electric | Nathan Lewis Cole | — | (530) 244 9229 | Electricians | Redding · Shasta County | — | — |
| A-1 Electric Service Company INC | Scott Thomas Pieper | — | (310) 204 1077 | Electricians | Culver City · Los Angeles County | — | — |
| A-1 Electrical | Ramon Jr Pando | — | (323) 221 0321 | Electricians | Upland · San Bernardino County | — | — |
| A-1 Electrical Services | Jeffrey Lee Moita | info@aelectricalservices.com | (510) 701 0240 | Electricians | Alameda · Alameda County | — | — |