Each utility shall file with the Commission a copy of its tariff which shall include: Rates. Each schedule of rates for service together with the applicable riders. Rules. The utility's rules, or terms and conditions, describing the utility's policies and practices in rendering service. These rules shall include: Extension Plan. The utility's plan for the installation of extensions of main and service lines where these facilities are in excess of those included in the regular rates for service and for which the customer shall be required to pay all or part of the cost. The customer's payments under this plan should be related to the investment that the utility prudently can make in consideration of the probable revenue. Voltages. A list of available voltages. Material Furnished by Utility. A list of the items which the utility furnishes, owns, and maintains on the customer's premises, such as meters, meter sockets, service entrances, etc. Billing Period. A statement indicating the minimum and maximum number of days for which the utility will bill a customer at its regular monthly rates for service. Payment Period. A statement indicating the minimum number of days allowed for payment of the gross amount of the customer's bill before service will be terminated for non-payment. Wastage of Electricity. A general statement of the utility's policy in making adjustments for wastage of electricity when an accidental ground exists without the knowledge of the customer.