| Business | Phone |
| Widmer Engineering Inc 315 Liberty St, Butler 16001 | (724) 283-4306 |
| Gateway Engineers Inc 201 S Main St # 200, Butler 16001 | (724) 779-8940 |
| Gray-Warnick Engineering 201 S Main St # 200, Butler 16001 | (724) 287-1055 |
| Olsen & Assoc Llc 126 S Main St # 1, Butler 16001 | (724) 282-4786 |