When a customer has been overcharged or undercharged as a result of incorrect reading of the meter, incorrect application of rate schedule, incorrect connection of the meter, application of an incorrect multiplier or constant or other similar reasons, the amount of the overcharge shall be refunded to the customer or the amount of the undercharge may be billed to the customer as detailed in subparts 2 through 4.
When a utility has overcharged a customer, the utility shall calculate the difference between the amount collected for service rendered and the amount the utility should have collected for service rendered, plus interest, for the period beginning three years before the date of discovery. Interest must be calculated as prescribed by Minnesota Statutes, section 325E.02, paragraph (b). If the recalculated bills indicate that more than $1 is due an existing customer or $2 is due a person no longer a customer of the utility, the full amount of the calculated difference between the amount paid and the recalculated amount shall be refunded to the customer. The refund to an existing customer may be in cash or as credit on a bill. Credits shall be shown separately and identified. If a refund is due a person no longer a customer of the utility, the utility shall mail to the customer's last known address either the refund or a notice that the customer has three months in which to request a refund from the utility.
When a utility has undercharged a customer, the utility shall calculate the difference between the amount collected for service rendered and the amount the utility should have collected for service rendered, for the period beginning one year before the date of discovery. If the recalculated bills indicate that the amount due the utility exceeds $10, the utility may bill the customer for the amount due. But a utility must not bill for any undercharge incurred after the date of a customer inquiry or complaint if the utility failed to begin investigating the matter within a reasonable time and the inquiry or complaint ultimately resulted in the discovery of the undercharge. The first billing rendered shall be separated from the regular bill and the charges explained in detail.
If the date the error occurred can be fixed with reasonable certainty, the remedy shall be calculated on the basis of payments for service rendered after that date, but in no event for a period beginning more than three years before the discovery of an overcharge or one year before the discovery of an undercharge.
33 SR 215
October 9, 2008