| Business | Phone |
| Tma Geotechnical Engineering 8935 Shady Grove Ct, Gaithersburg 20877 | (301) 258-5053 |
| Professional Consulting Corp 943 Russell Ave # A, Gaithersburg 20879 | (301) 926-8569 |
| Edafos Geotechnical Consulting 6 Turnham Ln, Gaithersburg 20878 | (301) 309-6881 |
| Kim Engineering Inc 7824 Beechcraft Ave, Gaithersburg 20879 | (301) 987-8188 |