Utah Code Title 54. Public Utilities § 54-4-8. Additions, improvements, extensions, repairs, or changes--Apportioning costs

(1)(a) Whenever the commission shall find that additions, extensions, repairs, or improvements to or changes in the existing plant, equipment, apparatus, facilities, or other physical property of any public utility or of any two or more public utilities ought reasonably to be made, or that a new structure or structures ought to be erected to promote the security or convenience of its employees or the public or in any way to secure adequate service or facilities, the commission shall make and serve an order directing that such additions, extensions, repairs, improvements, or changes be made or such structure or structures be erected in the manner and within the time specified in the order.

(b) If any additions, extensions, repairs, improvements, or changes, or any new structure or structures which the commission has ordered to be erected, require joint action by two or more public utilities, the commission shall notify the public utilities that the additions, extensions, repairs, improvements, or changes, or new structure or structures have been ordered and shall be made at their joint cost; whereupon the public utilities shall have reasonable time as the commission may grant within which to agree upon the portion or division of cost of the additions, extensions, repairs, improvements, or changes or any new structure or structures which each shall bear.