| 1 Call Flood & Construction Specialist LLC | Shawn Bush | — | (619) 954 5162 | GC, remodel, ADU | El Cajon · San Diego County | — | — |
| 1 Click Electric | Cody Allyn Phillips | gerencia_comercial@click-electric.com | (760) 504 9282 | Electricians | San Marcos · San Diego County | — | — |
| 1 Day Aluminum Gutters | 1 Day Aluminum Gutters | — | (858) 472 6279 | Other | Poway · San Diego County | — | — |
| 1 Electrical Services | Andrew Boyd Davis | — | (858) 914 1211 | Electricians | San Diego · San Diego County | — | — |
| 1 Source Electrical INC | Carl Joseph Pizzuto | — | (760) 739 1987 | Electricians | San Marcos · San Diego County | — | — |
| 1-877 Appliance Repair INC | Ayriyan Gary | 1877appliance@gmail.com | (858) 222 9542 | HVAC | La Mesa · San Diego County | — | — |
| 1-888-wow-1 Day! Painting | Zachary Von Strehl Jaggers | — | (619) 955 0071 | Windows, patio, painters | San Diego · San Diego County | — | — |
| 1-stop Integrated Solutions LLC | Luis Alberto Reyna Gaytan | — | (760) 705 5639 | Other | Escondido · San Diego County | — | — |
| 101 Hardwood Flooring | 101 Hardwood Flooring | — | (760) 450 7429 | Other | Carlsbad · San Diego County | — | — |
| 101 Mobility Of San Diego | Todd Robert Girouard | — | (858) 800 2820 | GC, remodel, ADU | Carlsbad · San Diego County | — | — |
| 101 Stucco INC | John Hugh Coutts | — | (760) 801 2639 | Other | Encinitas · San Diego County | — | — |
| 1010 Electric | Matt Mohammad Sohrabi | — | (760) 807 5555 | Electricians | San Marcos · San Diego County | — | — |
| 1015 Construction | Arthur Charles Mansir | — | (760) 415 4245 | GC, remodel, ADU | Escondido · San Diego County | — | — |
| 10ten Construction LLC | Jessica Marie Gilmour | — | (760) 712 7840 | GC, remodel, ADU | Fallbrook · San Diego County | — | — |
| 10x33 Construction Consulting | Zakar Gamaliel Jayne | — | (619) 995 1023 | GC, remodel, ADU | San Diego · San Diego County | — | — |
| 1111 Construction | Chad Edward Emery | guy@infinitydesignbuild.com | (760) 420 7236 | Electricians | Vista · San Diego County | — | — |
| 1224 INC | Jamison Scott Persons | — | (619) 206 0811 | Other | San Diego · San Diego County | — | — |
| 123 Floor | James Wendell Cantwell | sdjim6@gmail.com | (858) 583 0377 | Other | San Diego · San Diego County | — | — |
| 123 Remodeling Ca INC | David Lavi | dreamsrenovationca@gmail.com | (858) 240 1123 | GC, remodel, ADU | San Diego · San Diego County | — | — |
| 13zero3 Construction | Gaetano Gino Giacalone | eben@eyebytes.com | (619) 731 4242 | GC, remodel, ADU | San Diego · San Diego County | — | — |
| 180 Roofing Pros | Kenneth Edward Walter | — | (760) 264 4003 | Other roofers | Escondido · San Diego County | — | — |
| 1800 Anytime Plumbing Heating & Air | Geno Anthony Gruber | — | (800) 269 8463 | HVAC | Coronado · San Diego County | — | — |
| 1904 Construction | Reid Michael Schneider | — | (619) 550 6384 | GC, remodel, ADU | Lakeside · San Diego County | — | — |
| 1904 Garage Doors & Gates INC | Alexander Joseph Johnson | info@garagedoorsgates.com | (619) 962 1564 | Other | San Diego · San Diego County | — | — |
| 1904 Glazing INC | Oscar Efren Verduzco Casillas | — | (619) 915 1931 | Windows, patio, painters | Chula Vista · San Diego County | — | — |
| 1M Enterprises INC | Nicholas Ryan Fleming | — | (760) 697 6999 | GC, remodel, ADU | Oceanside · San Diego County | — | — |
| 1quality Construction Corp | Jose Luis Hernandez Tellez | — | (760) 310 6308 | GC, remodel, ADU | Vista · San Diego County | — | — |
| 1st Aid Drainage & Plumbing INC | Ricardo Bernal | — | (619) 454 2704 | Other | Lemon Grove · San Diego County | — | — |
| 1st Choice Backflow And Construction | Henry George Kohlmann | — | (760) 468 4026 | GC, remodel, ADU | Bonsall · San Diego County | — | — |
| 1st Choice Drywall INC | Rogelio Silva-Espitia | — | (619) 799 8404 | Other | Lemon Grove · San Diego County | — | — |
| 1st Choice Plumbing Heating And Air | Fernando Andres Jr Rojas | — | (760) 696 1201 | HVAC | Oceanside · San Diego County | — | — |
| 1st Class Plumbing | 1st Class Plumbing | — | (760) 925 1336 | Other | Escondido · San Diego County | — | — |
| 1st First Prodoor | Jesse Calderon | — | (619) 942 2570 | Other | El Cajon · San Diego County | — | — |
| 1st Response Plumbing & Flood Damage | Robert Damien Cervantes | jared@1stresponseplumbing.com | (858) 203 0930 | HVAC | National City · San Diego County | — | — |
| 1st Watch Technology Solution Incorporated | Shawn Anthony M Dalugdug Kenville | hello@rfuenzalida.com | (833) 302 5276 | Electricians | Chula Vista · San Diego County | — | — |
| 1up Drywall | Luis Antonio Garcia | — | (760) 532 6656 | Other | Escondido · San Diego County | — | — |
| 1vision Roof Pros | Sergio Duron | — | (619) 289 6378 | Other roofers | San Diego · San Diego County | — | — |
| 2 Bros Construction INC | Aispuro Jonathan Guerrero | jordan@bros-construction.com | (619) 496 1364 | GC, remodel, ADU | San Diego · San Diego County | — | — |
| 2 Brothers Construction INC | Mike Iloski | — | (760) 802 5539 | GC, remodel, ADU | Escondido · San Diego County | — | — |
| 2 Day Painting | 2 Day Painting | — | (619) 646 5452 | Windows, patio, painters | San Diego · San Diego County | — | — |