Each public utility and each railroad corporation, subject to the jurisdiction of the commission, and subject to the provisions of this act, shall pay to the commission in each year, a special regulatory fee in such amount as the commission shall find and determine to be necessary, together with the amount of all other fees paid or payable to the commission by each such public utility and railroad corporation in the current calendar year, to defray the amount to be expended by the commission for expenses in supervising and regulating the public utilities and railroad corporations subject to its jurisdiction.
Idaho Code § 61-1001