| Case Number | Case Title | Open Date | Closed Date |
| 18-0438-WS-COI | IN THE MATTER OF THE COMMISSION'S INVESTIGATION INTO COLUMBIA MHC EAST, LLC DBA COLUMBIA PARK WATER AND SEWER SYSTEM | 03/13/2018 | |
| 18-1294-WS-AEM | Columbia MHC East LLC | 08/15/2018 | 10/04/2023 |
| 18-1330-WS-ACE | AQUA OHIO INC/AQUA WASTEWATER INC | 08/24/2018 | 10/04/2023 |
| 18-1331-WS-ATA | AQUA OHIO INC/AQUA WASTEWATER INC | 08/24/2018 | 10/04/2023 |
| 18-1528-WS-AIR | Columbia MHC East LLC d/b/a Columbia Park Water and Sewer System | 10/09/2018 | 10/04/2023 |