Colo. Rev. Stat. § 40-4-108
The commission has power, after hearing upon its own motion or upon complaint, to ascertain and fix just and reasonable standards, classifications, regulations, practices, measurements, or service to be furnished, imposed, observed, and followed by all electric, gas, and water public utilities; to ascertain and fix adequate and serviceable standards for the measurement of quantity, quality, pressure, initial voltage, or other condition pertaining to the supply of the product, commodity, or service furnished or rendered by any such public utility; to prescribe reasonable regulations for the examination and testing of such product, commodity, or service and for the measurement thereof; to establish reasonable rules, regulations, specifications, and standards to secure the accuracy of all meters and equipment for measurement and weighing; and to provide for the examination and testing of any and all equipment used for the measurement or weighing of any product, commodity, or service of any such public utility.
C.R.S. § 40-4-108