Colo. Rev. Stat. § 29-8-132
The public utility has the duty to maintain, repair, and replace all underground facilities installed under this article. There shall be no competitive bidding as to the construction of the converted facilities since existing facilities are owned, maintained, and operated by the public utility and the continuity of service of the utility is essential, both of which make construction work by third persons impracticable. Therefore, the public utility concerned shall be responsible for the accomplishment of all construction work and may contract out such of the construction work as it deems desirable. Title to the converted facilities shall be at all times solely and exclusively in the public utility involved, as the public is only purchasing the intangible benefits which come from converted facilities, that is, the removal of the overhead facilities and replacement by underground facilities.
C.R.S. § 29-8-132