Public utilities, and municipalities or their agencies furnishing public utility service beyond their corporate limits, may require deposits to secure future payments of rates, subject to the following:
(1) Deposits may be required from customers taking service for a period of less than 30 days, in an amount equal to the estimated gross bill for such temporary period. Deposits may be required from all other customers, except that in no instance may deposits be required in excess of the estimated gross bill for any single billing period plus one month, the maximum period not to exceed four months, with a minimum of $5.00.(2) Deposits secured from a domestic customer or residential subscriber shall be returned to the depositor when he pays undisputed bills for service over a period of 12 consecutive months. Any such customer, having secured the return of a deposit, shall not be required to make a new deposit, unless the service has been discontinued, or the credit standing of the customer has been impaired through failure to comply with tariff provisions.(3) The payment of any undisputed bill, within the meaning of the Public Utility Law (66 P.S. § 1101 et seq.), shall be payment of the bill with or without discount or penalty, within 30 days following the period for which the bill was rendered or payment within 30 days following presentation of the bill, or the payment of any contested bill, payment of which is withheld beyond such period and the dispute is terminated substantially in favor of the customer and payment made by the customer within ten days thereafter.(4) All tariffs shall provide for interest on deposits at the rate of 6.0% annually without deduction for any taxes on such deposits. This section cited in 52 Pa. Code § 56.34 (relating to deposits for temporary service); and 52 Pa. Code § 56.284 (relating to deposits for temporary service).