Idaho Code § 63-2704
Every such producer shall render to the state tax commission of the state of Idaho on forms prescribed, prepared and furnished by the state tax commission, the statement required under section 63-2701, Idaho Code, sworn to by the manager, president, secretary or treasurer of such producer, showing the number of kilowatt hours of electricity and electrical energy produced, generated or manufactured by him or it in the state of Idaho during the period to which the tax statement relates through and by means of water power, and the number of kilowatt hours subject to the tax imposed by this chapter. For the purpose of measuring such electricity and electrical energy such producer shall keep and maintain at the point or points of production, a recording watt hour meter or meters, or other suitable instrument for measuring the electricity or electrical energy produced, of a type to be approved by the state tax commission, and, subject to rules and regulations prescribed by the state tax commission under this chapter, shall compute the number of kilowatt hours subject to the tax imposed by this chapter during each monthly period, such recordings and computations to be kept on file at the principal place of business of such producer within the state of Idaho and same together with the books and records of such producer shall be subject to the inspection of the state tax commission, their deputies or assistants, during reasonable business hours.
Idaho Code § 63-2704