| Industrial Power Solutions | Steven Lee Mote | — | (209) 256 5456 | Electricians | Jackson · Amador County | — | — |
| J & J Construction | James Jeremiah Lynch | — | (209) 535 7777 | GC, remodel, ADU | Sutter Creek · Amador County | — | — |
| J & M Painting | J & M Painting | — | (209) 295 4355 | GC, remodel, ADU | Pioneer · Amador County | — | — |
| J C Construction Company | James Clinton Whitaker | — | (916) 591 8960 | GC, remodel, ADU | Sutter Creek · Amador County | — | — |
| J Estrada Construction INC | Julio Cesar Estrada Espinoza | — | (209) 304 3983 | GC, remodel, ADU | Jackson · Amador County | — | — |
| J Katsma Construction | Jason Trent Katsma | — | (209) 418 8785 | GC, remodel, ADU | Jackson · Amador County | — | — |
| J L Builders | J L Builders | — | (209) 295 3323 | GC, remodel, ADU | Pioneer · Amador County | — | — |
| J Ruiz Painting | J Ruiz Painting | — | (209) 217 7070 | Windows, patio, painters | Jackson · Amador County | — | — |
| J S Plumbing And Drain | J S Plumbing And Drain | jsplumbingdrain@gmail.com | (209) 304 9536 | Other | Pioneer · Amador County | — | — |
| J T L & Co | James William Trythall | — | (209) 295 1245 | Electricians | Pioneer · Amador County | — | — |
| J Vila Builders LLC | Joe Anthony Vila | — | (925) 586 1477 | GC, remodel, ADU | Sutter Creek · Amador County | — | — |
| Jamen's Family Plumbing | Benjamen Lawrence Martinez | — | (209) 399 0182 | Other | Pine Grove · Amador County | — | — |
| James Richard Ulm | James Richard Ulm | — | (209) 274 4816 | HVAC | Ione · Amador County | — | — |
| Jardine Construction | Steven Rickey Jardine | — | (209) 304 1514 | GC, remodel, ADU | Pine Grove · Amador County | — | — |
| Jason Cornell Drywall INC | Jason Christopher Cornell | — | (209) 419 0515 | Other | Pine Grove · Amador County | — | — |
| Jaw Heating & Air INC | Joseph Edward White | — | (209) 223 1152 | HVAC | Jackson · Amador County | — | — |
| Jay Maki Construction | Jay William Maki | — | (916) 947 8591 | GC, remodel, ADU | Volcano · Amador County | — | — |
| Jeff Edwards Flooring | Jeff Edwards Flooring | — | (209) 304 8644 | Other | Sutter Creek · Amador County | — | — |
| Jeff Williams - General Contractor | Jeff Williams - General Contractor | — | (831) 818 8659 | GC, remodel, ADU | Pine Grove · Amador County | — | — |
| Jeffery S Kelley Construction | Jeffery Scott Kelley | — | (209) 295 3434 | GC, remodel, ADU | Pioneer · Amador County | — | — |
| Jennings Construction | Kevin Christian Jennings | — | (209) 267 1221 | GC, remodel, ADU | Amador City · Amador County | — | — |
| Jim Josse Construction | James Walter Josse | — | (209) 295 4000 | GC, remodel, ADU | Pine Grove · Amador County | — | — |
| Joe Bender's Counter Design | Joe Bender's Counter Design | — | (209) 304 6281 | Other | Jackson · Amador County | — | — |
| John K Gonsalves General Contractor | John K Gonsalves General Contractor | — | (209) 304 5187 | GC, remodel, ADU | Jackson · Amador County | — | — |
| Jolson Welding | Jolson Welding | — | (530) 633 2933 | Other | Pine Grove · Amador County | — | — |
| Josh Mc Eachron Construction | Joshua Michael Mc Eachron | — | (209) 327 0534 | GC, remodel, ADU | Ione · Amador County | — | — |
| Josh West Concrete | Josh West Concrete | — | (916) 798 4621 | Other | Ione · Amador County | — | — |
| Just Repairs Pools | Just Repairs Pools | hello@rfuenzalida.com | (916) 396 2277 | Pool | Ione · Amador County | — | — |
| K & M Plumbing | K & M Plumbing | — | (775) 901 8016 | Other | Volcano · Amador County | — | — |
| K C P Kevin Copley Painting | Kevin Donald Copley | — | (408) 679 2869 | Windows, patio, painters | Pioneer · Amador County | — | — |
| K K Enterprise | K K Enterprise | — | (209) 419 0971 | Other | Volcano · Amador County | — | — |
| K R Ford Construction | Kurt Robert Ford | — | (530) 416 1405 | GC, remodel, ADU | Volcano · Amador County | — | — |
| K W Construction | Kevin Robert Warren | alecia@kwconstruction.com | (209) 304 5080 | GC, remodel, ADU | Pioneer · Amador County | — | — |
| Kas Landscape Services | Kevin August Smith | — | (209) 296 5468 | Windows, patio, painters | Volcano · Amador County | — | — |
| Kell Fire Protection Services INC | Ty Brandon Kell | — | (916) 826 2968 | Other | Jackson · Amador County | — | — |
| Ken Moller Construction Incorporated | Kenneth James Moller | — | (209) 267 5575 | GC, remodel, ADU | Sutter Creek · Amador County | — | — |
| Kirkpatrick Painting | Kirkpatrick Painting | — | (209) 770 0712 | Windows, patio, painters | Pine Grove · Amador County | — | — |
| Km Land Improvement INC | Kevin Anthony Malia | — | (209) 256 7076 | Other | Volcano · Amador County | — | — |
| Koko Roofing | Christopher Keith Koko | — | (209) 223 0990 | Other roofers | Pine Grove · Amador County | — | — |
| Kreth INC | Richard H Kreth | — | (209) 274 2446 | Other | Ione · Amador County | — | — |