| Business | Phone |
| Heg Engineering Llc 672 Marina Dr # 204, Charleston 29492 | (843) 881-9804 |
| Hdr Engineering Inc 2000 Sam Rittenberg Blvd #2020, Charleston 29407 | (843) 416-1160 |
| Hybrid Technologies 828 Harbor Place Dr, Charleston 29412 | (843) 795-9985 |
| Watermark Engineering Llc 705 Saint Andrews Blvd, Charleston 29407 | (843) 225-7191 |