Colo. Rev. Stat. § 37-85-103
The board of county commissioners of each county, at its regular sessions in each year, and at such other sessions as it in its discretion may deem proper, in view of the irrigation and harvesting season, and the convenience of all parties interested, shall hear and consider all applications which may be made to it by any party interested, either in furnishing and delivering for compensation in any manner, or in procuring for such compensation, water for irrigation, mining, milling, manufacturing, or domestic purposes, from any ditch, canal, conduit, or reservoir, the whole or any part of which lies in such county. The application shall be supported by such affidavits as the applicant may present, showing reasonable cause for such board of county commissioners to proceed to fix a reasonable maximum rate of compensation for water to be thereafter delivered from such ditch, canal, conduit, or reservoir, within such county.
C.R.S. § 37-85-103