Any supplier may at any time on or after July 1, 1964, apply to the board to establish its service area. In such case and in all cases where agreements have not been entered into, including cases arising under section 70-1008, the secretary shall give written notice to the parties involved citing them to appear at a time, not less than thirty days thereafter, and at a place specified in the notice for a hearing upon the matter of establishing the service areas concerned in the notice. The provisions of this section shall not apply to service within the corporate limits of any municipality.