| 5 Star Pipes | 5 Star Pipes | — | (415) 405 5067 | Other | San Francisco · San Francisco County | — | — |
| 8 A Plumbing | 8 A Plumbing | — | (510) 815 4029 | Other | San Francisco · San Francisco County | — | — |
| A & A Plumbing | A & A Plumbing | — | (415) 672 1640 | Other | San Francisco · San Francisco County | — | — |
| A & H Door And Access Control | Walter Rafael Rojas | — | (650) 271 0291 | Other | San Francisco · San Francisco County | — | — |
| A & K Plumbing INC | Zhanhong Zeng | — | (415) 205 7091 | Other | San Francisco · San Francisco County | — | — |
| A & R Plumbing | William Javier Mendieta | — | (415) 586 6851 | Other | San Francisco · San Francisco County | — | — |
| A A Discount Phone System | A A Discount Phone System | — | (415) 664 8000 | Other | San Francisco · San Francisco County | — | — |
| A C Contracting | Covarrubias Adrian | — | (415) 297 4687 | Other | San Francisco · San Francisco County | — | — |
| A E W Engineering INC | Kenneth Ping-sang Leung | — | (415) 495 8400 | Other | San Francisco · San Francisco County | — | — |
| A G Quality Plumbing | Agustin Cruz Garcia | — | (415) 824 2517 | Other | San Francisco · San Francisco County | — | — |
| A General Engineering Company | Alejandro Hernandez | — | (510) 734 4666 | Other | San Francisco · San Francisco County | — | — |
| A M F K Industries INC | Andrew Eunkyu Kim | — | (415) 390 5804 | Other | San Francisco · San Francisco County | — | — |
| A M West Mechanical INC | Lutsker Sam | info@amwestmechanical.com | (415) 254 2931 | Other | San Francisco · San Francisco County | — | — |
| A Mc Carthy Engineering INC | Angus Fursey Mc Carthy | — | (415) 269 1780 | Other | San Francisco · San Francisco County | — | — |
| A P R Service | Ruben Cristobal Tse | — | (415) 370 9221 | Other | San Francisco · San Francisco County | — | — |
| A Plumbing | A Plumbing | — | (415) 336 5098 | Other | San Francisco · San Francisco County | — | — |
| A Plumbing Company | Zhang Guan Dong | — | (415) 713 3186 | Other | San Francisco · San Francisco County | — | — |
| A Plus Garage Door Corp | Edgar David Nolasco | — | (415) 386 2136 | Other | San Francisco · San Francisco County | — | — |
| A R Plumbing | A R Plumbing | — | (415) 312 1751 | Other | San Francisco · San Francisco County | — | — |
| A T D Tile | A T D Tile | — | (415) 225 5340 | Other | San Francisco · San Francisco County | — | — |
| A V A | A V A | — | (415) 317 0350 | Other | San Francisco · San Francisco County | — | — |
| A3 Pipeline | Alfredo Gonzalez | — | (415) 300 0364 | Other | San Francisco · San Francisco County | — | — |
| Access Scaffolding Co | Igor Vassiliev | — | (510) 230 5040 | Other | San Francisco · San Francisco County | — | — |
| Ace Automatic Garage Doors INC | Hernandez Miguel | — | (415) 826 7686 | Other | San Francisco · San Francisco County | — | — |
| Acme Bay Area Backflow INC | Mark Richard Delzer | — | (415) 505 3917 | Other | San Francisco · San Francisco County | — | — |
| Active Scaffold | Juan Carlos Romero | active.scaffolding@hotmail.co.uk | (415) 912 7454 | Other | San Francisco · San Francisco County | — | — |
| Actnet Advanced Technology Corporation | Julie Yi Zhou | — | (415) 661 9000 | Other | San Francisco · San Francisco County | — | — |
| Ad Art INC | Terry Jack Long | — | (415) 869 6464 | Other | San Francisco · San Francisco County | — | — |
| Adrian P Harty | Adrian P Harty | — | (415) 342 3170 | Other | San Francisco · San Francisco County | — | — |
| Advanced Plumbing And Drain INC | Nicholas Wayne Bobos | — | (415) 744 4944 | Other | San Francisco · San Francisco County | — | — |
| Aimhigh Scaffolding INC | Kenny Jing Yi Li | — | (415) 652 0161 | Other | San Francisco · San Francisco County | — | — |
| Alan Merritt | Alan Merritt | — | (415) 845 7018 | Other | San Francisco · San Francisco County | — | — |
| Alec Morgan Construction INC | Alec Charles Morgan | — | (415) 936 3614 | Other | San Francisco · San Francisco County | — | — |
| Alex Sweeney Construction INC | Alex Michael Sweeney | — | (415) 916 9338 | Other | San Francisco · San Francisco County | — | — |
| Alex's Custom Tile | Alex's Custom Tile | — | (415) 806 4524 | Other | San Francisco · San Francisco County | — | — |
| All Rooter & Plumbing Service INC | Minh Gia Luc | — | (415) 282 8289 | Other | San Francisco · San Francisco County | — | — |
| All-star Marble And Granite Corp | Nestor Romeo Rodriguez Zepeda | — | (408) 460 1017 | Other | San Francisco · San Francisco County | — | — |
| Alonso Tile Company | Robert Manuel Alonso | — | (415) 533 4292 | Other | San Francisco · San Francisco County | — | — |
| Alta Group INC | Glenele Oberrich | office@altagroup.rs | (510) 388 3582 | Other | San Francisco · San Francisco County | — | — |
| Amalfi Tile & Marble | Amalfi Tile & Marble | — | (415) 309 5482 | Other | San Francisco · San Francisco County | — | — |