| Company | Location | Certifications | License # |
|---|---|---|---|
| Advanced Trenchless Inc | Martinez, CA | Installer (C-42) | 971074 |
| All Bay Rooting And Plumbing Services | Lafayette, CA | Installer (C-42) | 821259 |
| All Water Heaters & Plumbing Llc | Concord, CA | Installer (C-42) | 1143044 |
| American Pipe Bursting Llc | Martinez, CA | Installer (C-42) | 1039462 |
| Avalon Rooter | Richmond, CA | Installer (C-42) | 1067780 |
| Bay Flow Sewers | San Pablo, CA | Installer (C-42) | 1155098 |
| Bay Plumbing & Rooter Llc | Rodeo, CA | Installer (C-42) | 929458 |
| Better Rooter Inc | Richmond, CA | Installer (C-42) | 1035198 |
| Betti Val Plumbing & Heating Inc | Richmond, CA | Installer (C-42) | 196928 |
| Clear Water Mechanical Plumbing & Underground | Clyde, CA | Installer (C-42) | 931971 |
| Corsa Plumbing And Rooter | Pleasant Hill, CA | Installer (C-42) | 1091604 |
| Davila Plumbing Company Inc | Brentwood, CA | Installer (C-42) | 934263 |
| Drain Doctors And Plumbers | Antioch, CA | Installer (C-42) | 944651 |
| Drainman Pro Inc | Antioch, CA | Installer (C-42) | 881542 |
| Echo Plumbing And Rooter | Concord, CA | Installer (C-42) | 1033391 |
| Ernie'S Plumbing & Sewer Service | Martinez, CA | Installer (C-42) | 802333 |
| Erwyn'S Plumbing | Richmond, CA | Installer (C-42) | 1050217 |
| Everest Plumbing And Drain | El Sobrante, CA | Installer (C-42) | 945398 |
| First Class Water Heaters Inc | Pittsburg, CA | Installer (C-42) | 1024238 |
| Flowing Water | Pacheco, CA | Installer (C-42) | 1111542 |
| Guerra Bros Plumbing Inc | Concord, CA | Installer (C-42) | 802256 |
| H & R Underground | El Sobrante, CA | Installer (C-42) | 878364 |
| In Demand Plumbing Heating & Air Inc | Antioch, CA | Installer (C-42) | 943549 |
| Lifesaver Plumbing And Rooter | Pinole, CA | Installer (C-42) | 1134533 |
| Magnificent Plumbing & Rooter Inc | San Ramon, CA | Installer (C-42) | 1018622 |
| Malachi Plumbing Inc | Oakley, CA | Installer (C-42) | 1072451 |
| Marelich Mechanical Co Inc | Martinez, CA | Installer (C-42) | 752638 |
| Matheneys Plumbing & Heating | Danville, CA | Installer (C-42) | 933520 |
| N V Heathorn Co | Concord, CA | Installer (C-42) | 761659 |
| Olsson Plumbing Company | Danville, CA | Installer (C-42) | 443706 |
| Ortega Plumbing & Rooter Llc | Richmond, CA | Installer (C-42) | 1105758 |
| Plumbing Express Inc | Pinole, CA | Installer (C-42) | 714073 |
| Plumbing Pro | Hercules, CA | Installer (C-42) | 930861 |
| Pure Water Plumbing | Oakley, CA | Installer (C-42) | 1016056 |
| Rooter-Man | Walnut Creek, CA | Installer (C-42) | 646020 |
| Royal Rooter | Antioch, CA | Installer (C-42) | 862460 |
| Service Pros Plumbers Inc | Antioch, CA | Installer (C-42) | 979455 |
| Sewer And Drain Masters Corporation | Richmond, CA | Installer (C-42) | 808055 |
| Sewer Connection Inc | El Sobrante, CA | Installer (C-42) | 796452 |
| Superior Plumbing & Drain Cleaning Services | Richmond, CA | Installer (C-42) | 915553 |
| Symbolic Plumbing | San Ramon, CA | Installer (C-42) | 1136896 |
| Tankless Water Heater Experts | San Ramon, CA | Installer (C-42) | 992032 |
| U S T Testing Services Inc | Concord, CA | Installer (C-42) | 866797 |
| White L H General Building Contractor | Lafayette, CA | Installer (C-42) | 275246 |
44 companies in the CSLB Licensed C-42 Sanitation System Contractors are based in Contra Costa County as of 2026-07-23. Companies based elsewhere in California also commonly serve the county.
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