Colo. Rev. Stat. § 32-11-533
Subject to the provisions of sections 32-11-564 and 32-11-566, no indebtedness shall be incurred by the issuance of district securities or by any contract by which the district agrees to repay as general obligations of the district to the federal government or to any public body over a term not limited to the then current fiscal year any project costs advanced thereby under any contract for the acquisition of the project or any interest therein, advanced by the issuance of securities of such a public body to defray any cost of the project or of facilities thereby acquired and becoming a part of the district's facilities, or otherwise advanced, unless a proposal of issuing the district's general obligation bonds, including the maximum net effective interest rate at which such issue of bonds may be issued, or of incurring an indebtedness by the district by making such a contract is submitted and approved at an election held for that purpose in accordance with part 4 of this article and with all laws amendatory thereof and supplemental thereto.
C.R.S. § 32-11-533