Colo. Rev. Stat. § 39-5-121.5
At the written request of any taxpayer or any agent of such taxpayer and subject to such confidentiality requirements as provided by law, the assessor shall, within seven working days after receipt of said request, make available to the taxpayer or agent the data used by the assessor in determining the actual value of any property owned by such taxpayer. At the assessor's election, the assessor may either mail, fax, or send by electronic transmission to the address, phone number, or electronic address supplied by said taxpayer or agent such data. Such data shall include but shall not be limited to the data derived from the declarations filed pursuant to the provisions of article 14 of this title and confidential data, provided that such confidential data shall be presented in such a manner that the source cannot be identified. Upon receipt of such request, the assessor shall notify the taxpayer or agent of the estimated cost of providing such information, payment of which shall be made prior to providing such information. Upon providing such information, the assessor may include a bill for the reasonable cost above the estimated cost and up to the statutory maximum which shall be due and payable upon receipt by the taxpayer or agent.
C.R.S. § 39-5-121.5