C.R.S. § 31-25-527

All special assessments for local improvements shall be due and payable within thirty days after the final publication of the assessing ordinance without demand; but all such assessments may be paid, at the election of the owner, in installments with interest as provided in section 31-25-528 . All special assessments for local improvements authorized in section 31-25-502 (2) may be due and payable at such alternate time or times as set forth in the assessing ordinance.