C.R.S. § 29-15-109

No action or proceeding, at law or in equity, to review any act or proceeding, or to question the validity or enjoin the performance of any act or the issuance of any tax anticipation notes authorized by this article, or to obtain any other relief against any acts or proceedings done or had under this article, whether based upon irregularities or jurisdictional defects, shall be maintained unless such action or proceeding is commenced within thirty days after the performance of the act or the effective date of the legislative act complained of; otherwise, it shall be thereafter perpetually barred.