C.R.S. § 31-4-104: Wards.

Every city shall be divided by the city council into wards, and such wards shall be numbered consecutively beginning with the number one. The boundaries of said wards shall not be changed more often than once in six years, unless change is necessary to conform to constitutional apportionment requirements. Territory added to the city shall become a part of such ward or wards as may be determined by ordinance; but this shall not prevent apportionment to conform to constitutional requirements. The boundaries and number of wards shall be changed only by majority vote of all members elected to the governing body.