| West C Builders INC | Anton Dreyen Council | — | (707) 224 8867 | GC, remodel, ADU | Napa · Napa County | — | — |
| West Coast Floor Company | Jesus Alfredo Martinez | — | (707) 297 2476 | Other | Napa · Napa County | — | — |
| West Coast Water | West Coast Water | interested@domainmarket.com | (707) 338 9876 | Other | Napa · Napa County | — | — |
| West Coast Well And Pump | West Coast Well And Pump | — | (707) 815 3288 | Other | Napa · Napa County | — | — |
| Westenrider Electric | Sean Wesley Westenrider | — | (707) 200 2181 | Electricians | Angwin · Napa County | — | — |
| Western States Investors INC | Douglas Lane| Ulery Doug Lane Ulery | — | (707) 590 0224 | GC, remodel, ADU | St Helena · Napa County | — | — |
| Westwood Construction | Jose Roberto Olguin | — | (707) 363 5433 | GC, remodel, ADU | Napa · Napa County | — | — |
| Wfr Development | Wfr Development | — | (707) 363 5105 | GC, remodel, ADU | Yountville · Napa County | — | — |
| Whitehill Construction | Leigh Andrew Whitehill | — | (707) 252 2515 | GC, remodel, ADU | Napa · Napa County | — | — |
| Whitney & Sons INC | Kevin Leon Whitney | — | (707) 287 2645 | GC, remodel, ADU | Napa · Napa County | — | — |
| Wightman Built INC | Daniel William Wightman | — | (408) 674 0035 | GC, remodel, ADU | St Helena · Napa County | — | — |
| Wilder's Tree Care | Wilder's Tree Care | — | (707) 812 4262 | Tree | Napa · Napa County | — | — |
| William Andrew Fennell | William Andrew Fennell | — | (925) 323 8970 | GC, remodel, ADU | Calistoga · Napa County | — | — |
| William Kreysler & Associates INC DBA Kreysler & Associates | William Bartley Kreysler | — | (707) 552 3500 | Other | American Canyon · Napa County | — | — |
| William L Bounsall Construction INC | William Logan Bounsall | — | (707) 484 4632 | Other | Calistoga · Napa County | — | — |
| Willoughby Construction | Jackson Blue Willoughby | — | (707) 337 2916 | GC, remodel, ADU | Napa · Napa County | — | — |
| Wine Country Development INC | Jacob John Songer | — | (707) 492 8214 | GC, remodel, ADU | Napa · Napa County | — | — |
| Wine Country Electric Napa LLC | Joshua Cruz Debonis | — | (707) 738 8681 | Electricians | Napa · Napa County | — | — |
| Wine Country Gardens | Jose De Jesus Guerrero Lona | — | (707) 975 7232 | Windows, patio, painters | Yountville · Napa County | — | — |
| Wine Country Pavers | Everton De Oliveira Rocha | info@winecountrypavers.com | (707) 205 1265 | GC, remodel, ADU | Napa · Napa County | — | — |
| Wine Country Plastering INC | Matthew Thomas Conatser | contact@sansoxygen.com | (707) 252 1960 | Other | Napa · Napa County | — | — |
| Wine Country Woodworking | Wine Country Woodworking | — | (707) 226 1224 | GC, remodel, ADU | Napa · Napa County | — | — |
| Wine Country Workshop | Wine Country Workshop | — | (707) 592 7010 | Other | Napa · Napa County | — | — |
| Wine Valley Electric | Edward Jean Bruner | — | (707) 333 7369 | Electricians | Napa · Napa County | — | — |
| Winery Heating Industrial Refrigeration Company | Connie Joann Rios-schellenger | — | (707) 737 4101 | HVAC | Calistoga · Napa County | — | — |
| Wlb Builders Ca INC | Jeremy Keoki Turner | — | (707) 225 1318 | GC, remodel, ADU | Napa · Napa County | — | — |
| Wooly's Electric INC | Toni Lynn Owen | — | (707) 252 2644 | Electricians | Napa · Napa County | — | — |
| Wv Painting INC | Wilber Valencia | — | (707) 312 9016 | Windows, patio, painters | Napa · Napa County | — | — |
| Wycoff Painting | Wycoff Painting | — | (707) 591 3717 | Windows, patio, painters | Calistoga · Napa County | — | — |
| Wyman Property Management Inc. | Wyman Property Management Inc. | info@wymanpm.com | (707) 224-0400 | Property managers | Napa · Napa County | — | — |
| Yager Carpentry | Yager Carpentry | — | (707) 812 0744 | Other | Napa · Napa County | — | — |
| Young's Painting & Deck Restoration | Young's Painting & Deck Restoration | — | (707) 253 7716 | Windows, patio, painters | Napa · Napa County | — | — |
| Z S Heating And Air INC | Zaid Tomas Szmidt | — | (707) 287 4027 | HVAC | Napa · Napa County | — | — |
| Zerba Construction | Mark Eugene Zerba | — | (707) 252 7363 | GC, remodel, ADU | Napa · Napa County | — | — |
| Zetina Construction LLC | Andrade Nabor | — | (707) 758 2323 | Electricians | Napa · Napa County | — | — |