| Business | Phone |
| Water Filtration Plant 1200 Adams St, St Clair 48079 | (810) 329-7121 |
| St Clair Administrative Dept 411 Trumbull St, St Clair 48079 | (810) 329-7121 |
| St Clair City Boat Harbor 902 S 2nd St, St Clair 48079 | (810) 329-4125 |
| St Clair City Bridge Tender M 29 & Pine Riveramp;, St Clair 48079 | (810) 329-9420 |