| Business | Phone |
| Cal Engineering & Geology Inc 1870 Olympic Blvd # 100, Walnut Creek 94596 | (925) 935-9771 |
| Dcm-Joyal Engineering 484 N Wiget Ln, Walnut Creek 94598 | (925) 945-0677 |
| Diablo Soil Engineers Inc 2726 N Main St, Walnut Creek 94597 | (925) 943-1200 |
| Geo Focus Geotechnical Engrs 49 Quail Ct # 200, Walnut Creek 94596 | (925) 945-1995 |
| Landslide & Foundation Failure 3708 N Mount Diablo Blvd, Walnut Creek 94596 | (925) 284-4208 |