| Wilson Painting | Wilson Painting | info@wilson-painting.com | (714) 720-5233 | Windows, patio, painters | Eureka · Humboldt County | — | — |
| Windy Point Fence Company | Jose Carlos Alejandre-Rodriguez | — | (707) 786 4452 | Other | Ferndale · Humboldt County | — | — |
| Winkelhaus Construction | Roy Arnold Winkelhaus | — | (707) 502 6217 | GC, remodel, ADU | Fortuna · Humboldt County | — | — |
| Wolf Electric | Joseph I Wolf | — | (707) 223 4188 | Electricians | Arcata · Humboldt County | — | — |
| Woodsy Plumbing | Woodsy Plumbing | — | (707) 498 4268 | Other | Kneeland · Humboldt County | — | — |
| Workhorse Welding LLC | Lonny Martin Whitlow | — | (208) 614-8780 | Other | Miranda · Humboldt County | — | — |
| Wormo LLC | Bernardo Matthew Jaime | — | (503) 816 0026 | GC, remodel, ADU | Willow Creek · Humboldt County | — | — |
| Worthy Construction | Arlo Roland Worthy | — | (707) 223 6864 | GC, remodel, ADU | Whitethorn · Humboldt County | — | — |
| Wyckoff Plumbing | Gary Lee Wyatt | — | (707) 725 4475 | Other | Fortuna · Humboldt County | — | — |
| X X Stripe & Construction INC | Garth Randolph Jr Sundberg | — | (707) 407 5986 | Other | Mc Kinleyville · Humboldt County | — | — |
| Young Enterprises | Donald Raymond Young | — | (707) 845 6428 | Windows, patio, painters | Willow Creek · Humboldt County | — | — |
| Younger Construction | Randall Dean Younger | — | (707) 496 6972 | Other | Eureka · Humboldt County | — | — |
| Your Local Mow Man | Geronimo Lavan Zuniga | humboldt@localmowman.com | (707) 572 8986 | Windows, patio, painters | Eureka · Humboldt County | — | — |
| Zack Cox Construction | Zachary William Cox | — | (707) 499 2949 | GC, remodel, ADU | Eureka · Humboldt County | — | — |
| Zane Mac Donald Construction | Zane Robert Mac Donald | — | (707) 442 8056 | GC, remodel, ADU | Eureka · Humboldt County | — | — |
| Zerlang's Construction | William Rene Zerlang | — | (707) 496 1905 | GC, remodel, ADU | Kneeland · Humboldt County | — | — |
| Zumbrun Construction | Richard Douglas Zumbrun | rzumbrun@gmail.com | (707) 498 1825 | GC, remodel, ADU | Arcata · Humboldt County | — | — |