(FORT WAYNE) - NIPSCO says it is cooperating with a state investigation into potential billing errors that led some customers to receive unusually high natural gas bills.
The investigation is being conducted by the Indiana Utility Regulatory Commission and began in November 2025 after NIPSCO alerted regulators to possible issues discovered during the rollout of its new Advanced Metering Infrastructure, or AMI.
The AMI system allows the utility to read meters remotely and replaces the older Automated Meter Reading modules. According to IURC documents, NIPSCO identified problems with a "not-insignificant" number of natural gas meters during the transition. Regulators also noted the company did not initially provide sufficient notice or explanation to affected customers.
In recent weeks, customers have taken to social media to report bills that were double or even triple their normal amounts.
In a statement released Monday, NIPSCO said customer safety and accurate billing remain its top priorities. The company emphasized that it proactively notified the IURC after discovering potential discrepancies and said the issue is not caused by the new AMI technology itself.
NIPSCO said fewer than 1% of its natural gas customers are affected. For customers who were billed for more than their actual usage, the company said it is issuing refunds covering up to 12 months of overbilling, in accordance with IURC rules.
"Customers do not need to take any action at this time," the company said, adding that it has already taken steps to verify and correct impacted bills and will continue to provide updates as more information becomes available.
The IURC investigation remains ongoing, and state officials have not indicated when a final determination will be made.