| West Coast Garage Doors | West Coast Garage Doors | — | (209) 952 0740 | Other | Stockton · San Joaquin County | — | — |
| West Coast Plumbing & Sewer | West Coast Plumbing & Sewer | — | (209) 688 3259 | Other | Stockton · San Joaquin County | — | — |
| West Valley Industries INC | Ronald David Jr Dufour | — | (209) 759 3600 | Electricians | Clements · San Joaquin County | — | — |
| West Valley Masonry | West Valley Masonry | — | (209) 740 1928 | Other | Tracy · San Joaquin County | — | — |
| Westbrook Rei Construction | Peter Michael Westbrook | — | (209) 481 7780 | GC, remodel, ADU | Lockeford · San Joaquin County | — | — |
| Western Refrigeration | Robb Kevin Sasaki | — | (209) 464 0427 | HVAC | Stockton · San Joaquin County | — | — |
| Western Steel Erectors INC | Gregory Allen Yates | — | (209) 838 6868 | Other | Escalon · San Joaquin County | — | — |
| Westmark Concrete | Westmark Concrete | — | (209) 426 6446 | Other | Lodi · San Joaquin County | — | — |
| White Construction INC | Brandon Ray White | — | (209) 625 6418 | GC, remodel, ADU | Lodi · San Joaquin County | — | — |
| White Glove Painting INC | Mario Alberto Hernandez Del Carmen | — | (510) 561 6353 | Windows, patio, painters | Lathrop · San Joaquin County | — | — |
| Wight Construction & Materials Company | Jose De Jesus Navarro | — | (209) 993 7825 | GC, remodel, ADU | Stockton · San Joaquin County | — | — |
| Wilbur Custom Home & Remodel | Wilbur Custom Home & Remodel | — | (209) 596 1278 | GC, remodel, ADU | Ripon · San Joaquin County | — | — |
| Willette Electrical | John Paul Willette | — | (209) 955 8658 | Electricians | Stockton · San Joaquin County | — | — |
| William Arthur Hobson | William Arthur Hobson | — | (707) 290 8386 | Windows, patio, painters | Lodi · San Joaquin County | — | — |
| William Casey Haynes | William Casey Haynes | — | (209) 712 2674 | Other | Lodi · San Joaquin County | — | — |
| William E Leer Construction INC | William Edward Iii Leer | — | (209) 303 6040 | GC, remodel, ADU | Ripon · San Joaquin County | — | — |
| William E Phillips Jr General Contractor | William Edgar Jr Phillips | — | (209) 333 1481 | GC, remodel, ADU | Lodi · San Joaquin County | — | — |
| William H Meyer | William H Meyer | — | (209) 480 1495 | Other | Ripon · San Joaquin County | — | — |
| William King Construction | William Scott King | — | (209) 993 1862 | GC, remodel, ADU | Lodi · San Joaquin County | — | — |
| William Mulder | William Mulder | — | (209) 679 5446 | GC, remodel, ADU | Ripon · San Joaquin County | — | — |
| William Nathan Thomas | William Nathan Thomas | — | (209) 603 5904 | GC, remodel, ADU | Stockton · San Joaquin County | — | — |
| Williams Service And Repair | Robert Lee Williams | — | (209) 479 6898 | GC, remodel, ADU | Lodi · San Joaquin County | — | — |
| Wills Plumbing | Wills Plumbing | — | (209) 992 8126 | Other | Stockton · San Joaquin County | — | — |
| Wilson Construction | Ronald Lyn Wilson | — | (209) 573 1959 | GC, remodel, ADU | Ripon · San Joaquin County | — | — |
| Wilson Construction Services INC | Reed Allen Wilson | — | (925) 605 6982 | GC, remodel, ADU | Lathrop · San Joaquin County | — | — |
| Wilson General Contracting INC | Wilson Lumanlan Magat | — | (925) 915 1606 | GC, remodel, ADU | Tracy · San Joaquin County | — | — |
| Window Washer | Window Washer | — | (209) 637 8631 | Other | Manteca · San Joaquin County | — | — |
| Wine Country Mechancal | Wine Country Mechancal | — | (916) 616 1274 | HVAC | Woodbridge · San Joaquin County | — | — |
| Winegarden Studio | Winegarden Studio | — | (209) 814 3014 | Windows, patio, painters | Manteca · San Joaquin County | — | — |
| Wire Tech Electric INC | Olvin Josue Rivera Perdomo | — | (925) 292 8005 | Electricians | Tracy · San Joaquin County | — | — |
| Wirepro Plus | Wirepro Plus | — | (510) 909 8795 | Other | Tracy · San Joaquin County | — | — |
| Wireteck Electric | Juan Manuel Vargas | — | (209) 505 3161 | Electricians | Escalon · San Joaquin County | — | — |
| Wm Universal Projects INC DBA Universal Heating & Cooling | Nicolas Vargas | — | (925) 844 4221 | HVAC | Lathrop · San Joaquin County | — | — |
| Wolfe Construction Company | Andrew P Jr Wolfe | wolfeconstruction@live.co.uk | (209) 200 9936 | GC, remodel, ADU | Woodbridge · San Joaquin County | — | — |
| Wood Construction | Chadrick Logan Wood | — | (209) 471 0498 | GC, remodel, ADU | Stockton · San Joaquin County | — | — |
| Wooden Tech Kitchen Cabinets | Wooden Tech Kitchen Cabinets | — | (209) 855 0549 | Other | Tracy · San Joaquin County | — | — |
| Woodhouse Construction | Steven Robert Woodhouse | — | (209) 992 0562 | GC, remodel, ADU | Lodi · San Joaquin County | — | — |
| Woodruff Construction | Larry Paul Woodruff | — | (209) 327 4588 | GC, remodel, ADU | Lodi · San Joaquin County | — | — |
| Woodside Construction | Mendoza Flaviano | joiner@woodside-construction.com | (209) 679 1271 | GC, remodel, ADU | Manteca · San Joaquin County | — | — |
| Woodworks By David | Woodworks By David | — | (209) 931 5412 | Other | Manteca · San Joaquin County | — | — |