Colo. Rev. Stat. § 25-15-317
The general assembly declares that it is in the public interest to ensure that environmental remediation projects protect human health and the environment. The general assembly finds that environmental remediation projects may leave residual contamination at levels that have been determined to be safe for a specific use, but not all uses, and may incorporate engineered structures that must be maintained or protected against damage to remain effective. The general assembly finds that in such cases, it is necessary to provide an effective and enforceable means of ensuring the conduct of any required maintenance, monitoring, or operation, and of restricting future uses of the land, including placing restrictions on drilling for or pumping groundwater for as long as any residual contamination remains hazardous. The general assembly, therefore, declares that it is in the public interest to create environmental covenants and notices of environmental use restrictions because such covenants and restrictive notices are necessary for the protection of human health and the environment.
C.R.S. § 25-15-317