| Business | Phone |
| Bellecci & Assoc 2290 Diamond Blvd # 100, Concord 94520 | (925) 685-4569 |
| Black & Veatch 1855 Gateway Blvd # 1000, Concord 94520 | (925) 246-8000 |
| Gilbert A Fitch & Assoc 1320 Galaxy Way # 101, Concord 94520 | (925) 682-6234 |
| Jes Engineering Inc 1355 Willow Way # 105, Concord 94520 | (925) 674-1151 |
| Milani Associates 4071 Port Chicago Hwy # 100, Concord 94520 | (925) 674-9082 |
| Rmr Design Group 1130 Burnett Ave # A, Concord 94520 | (925) 288-1917 |
| Seto & Assoc 1511 Rishell Dr, Concord 94521 | (925) 825-6560 |
| Brandon Consulting Inc 1375 Woodchuck Ln, Concord 94521 | (925) 459-9010 |
| Cole Management & Engineering Po Box 21547, Concord 94521 | (925) 609-8966 |
| Cordoba Consulting Inc 5368 Laurel Dr, Concord 94521 | (925) 671-5458 |
| Elliott V Ingram Land Srvyng 1310 La Vista Ave, Concord 94521 | (925) 689-4578 |
| Pacific Land Svc 2151 Salvio St, Concord 94520 | (925) 680-6406 |