| 101 Plumbing Humboldt INC | Isaac Arizona Kennedy | — | (707) 498 2707 | Other | Eureka · Humboldt County | — | — |
| 6 Rivers Construction INC | Zane Eldon Jr Grant | arielle.pennington@riversconstruction.com | (530) 515 7563 | Other | Hoopa · Humboldt County | — | — |
| Abbott Plumbing | Abbott Plumbing | — | (707) 499 5186 | Other | Arcata · Humboldt County | — | — |
| Agland Engineering INC | Steven Robert Hackett | — | (707) 786 4044 | Other | Ferndale · Humboldt County | — | — |
| Alba Plumbing And Fire Protection INC | Joshua Ryan Conley | — | (707) 834 1213 | Other | Eureka · Humboldt County | — | — |
| Albers Construction | Michael Shane Albers | keith@albersdc.com | (707) 764 2204 | Other | Rio Dell · Humboldt County | — | — |
| Allpoints Advertising INC | Geoffrey Howard Wills | — | (714) 655 0763 | Other | Eureka · Humboldt County | — | — |
| Anthonys Tile | Anthonys Tile | anthonystile@gmail.com | (707) 362 6356 | Other | Mc Kinleyville · Humboldt County | — | — |
| Arcata Cabinet & Design Company | Casey Eric Patton | — | (707) 826 2680 | Other | Arcata · Humboldt County | — | — |
| Arcata Finish Carpentry Fabricators | Arcata Finish Carpentry Fabricators | — | (707) 822 5447 | Other | Arcata · Humboldt County | — | — |
| Arcata Pro Floor INC | Lisa Louise Townsend-Scmitt | — | (707) 822 2838 | Other | Arcata · Humboldt County | — | — |
| B & B Hardscape INC | Penner Robert | — | (415) 302 0720 | Other | Eureka · Humboldt County | — | — |
| B C Ferreira Construction | Brian Louis Ferreira | — | (707) 839 8853 | Other | Mc Kinleyville · Humboldt County | — | — |
| B K Plumbing | B K Plumbing | — | (707) 616 4779 | Other | Fortuna · Humboldt County | — | — |
| Bc Drain Care Plumbing | Bc Drain Care Plumbing | — | (707) 601 6867 | Other | Ferndale · Humboldt County | — | — |
| Big Chunks Plumbing | Big Chunks Plumbing | bigchunksplumbing@gmail.com | (707) 719 2835 | Other | Eureka · Humboldt County | — | — |
| Bingham Tile | Bingham Tile | binghamtile@outlook.com | (707) 496 2290 | Other | Eureka · Humboldt County | — | — |
| Blr Construction | Brian Louis Redding | — | (530) 784 3636 | Other | Willow Creek · Humboldt County | — | — |
| Brad Vallerga Tile | Brad Vallerga Tile | — | (707) 502 1442 | Other | Arcata · Humboldt County | — | — |
| Bushnell Well Drilling | Bushnell Well Drilling | — | (707) 943 3617 | Other | Miranda · Humboldt County | — | — |
| C R Fence Company INC DBA Humboldt Fence Company | Russell Steven Renner | — | (707) 726 7965 | Other | Fortuna · Humboldt County | — | — |
| Cabinets By Andy | Andrew Bryan Dickey | — | (707) 839 0220 | Other | Mc Kinleyville · Humboldt County | — | — |
| Cacren Fencing | Cacren Fencing | — | (707) 496 3870 | Other | Rio Dell · Humboldt County | — | — |
| Cal Plumbing & Fire Suppression INC | Ryan Frank Rousseau | — | (707) 499 2631 | Other | Blue Lake · Humboldt County | — | — |
| Caledonia Plumbing | Caledonia Plumbing | — | (707) 845 1242 | Other | Carlotta · Humboldt County | — | — |
| Carbonneau Ceramic Tile Incorporated | Pierre Gerald Carbonneau | — | (707) 443 8842 | Other | Eureka · Humboldt County | — | — |
| Carpet Depot | Daniel Eugene Mealhouse | — | (707) 442 3470 | Other | Eureka · Humboldt County | — | — |
| Cedar Bay Plumbing | Cedar Bay Plumbing | — | (707) 499 6119 | Other | Eureka · Humboldt County | — | — |
| Century Mobile Homes | Century Mobile Homes | — | (707) 445 8411 | Other | Eureka · Humboldt County | — | — |
| Chamberlain Chimney Sweep | Chamberlain Chimney Sweep | — | (707) 443 5906 | Other | Eureka · Humboldt County | — | — |
| Charles Nganga Flooring | Charles Nganga Flooring | — | (707) 407 5863 | Other | Eureka · Humboldt County | — | — |
| Ciraulo Plumbing Services | Gary James Ciraulo | cirauloplumbing@gmail.com | (707) 497 4213 | Other | Eureka · Humboldt County | — | — |
| Citadel Masonry | Citadel Masonry | — | (707) 267 5836 | Other | Arcata · Humboldt County | — | — |
| Claybons Custom Tile And Design | Claybons Custom Tile And Design | — | (707) 672 4693 | Other | Eureka · Humboldt County | — | — |
| Clear Waters Plumbing | Clear Waters Plumbing | clearwatersplumbing@gmail.com | (707) 499 2581 | Other | Eureka · Humboldt County | — | — |
| Coast To Coast Plumbing | Coast To Coast Plumbing | dispatchexperienceplumbing@gmail.com | (707) 296 6804 | Other | Loleta · Humboldt County | — | — |
| Colin Ott Masonry | Colin Ott Masonry | — | (707) 443 4639 | Other | Eureka · Humboldt County | — | — |
| Collins Sheetmetal | Collins Sheetmetal | — | (408) 781 0806 | Other | Eureka · Humboldt County | — | — |
| Communications Cabling Systems INC | Daniel Robert Browne | dan.browne@communicationscablingsystems.com | (707) 442 2244 | Other | Eureka · Humboldt County | — | — |
| Concrete Pete | Concrete Pete | pete@concretepete.com | (707) 476 9469 | Other | Eureka · Humboldt County | — | — |