| Business | Phone |
| Parsons Corp 2121 N California Blvd, Walnut Creek 94596 | (925) 941-3700 |
| Fard Engineers Inc Chamberlain 309 Lennon Ln, Walnut Creek 94598 | (925) 944-7630 |
| Geo Strata 1630 N Main St # 259, Walnut Creek 94596 | (925) 798-1164 |
| International Resource Engr 1255 Treat Blvd, Walnut Creek 94597 | (925) 472-6972 |
| Macro Corp 1777 Oakland Blvd, Walnut Creek 94596 | (925) 210-1500 |