C.R.S. § 30-28-305

(1) The board of county commissioners shall have a subdivision exemption plat prepared for those properties in the land division study area for which the owners have: (a) Not elected to withdraw from the plan as provided in section 30-28-304 (3); (b) Given written consent to participate in the plan for platting and have supplied adequate evidence of title as required by section 30-28-304 (4). (2) The exemption plat shall be prepared by a professional land surveyor, and shall assign a lot number to each of the properties included in the exemption plat.