| Business | Phone |
| Lin Quest 8424 Dorsey Cir 201, Manassas 20110 | (703) 365-2550 |
| Cad-Con Consulting Inc 10706 Vandor Ln, Manassas 20109 | (703) 392-5141 |
| Eg & G 10687 Gaskins Way 101, Manassas 20109 | (703) 368-0100 |
| Professional Inspection 9423 Main St, Manassas 20110 | (703) 690-3777 |
| Emsi Engineering Inc 6997 Gateway Ct, Manassas 20109 | (703) 257-0877 |
| Fountain Consulting Inc 10382 Aragon Ct, Manassas 20110 | (703) 368-0825 |
| Mep Designs Inc 9300 Forest Point Cir, Manassas 20110 | (703) 366-3663 |