Colo. Rev. Stat. § 37-50-124
Except for the issuance of refunding bonds or other funding or refunding of obligations that does not increase the net indebtedness of the district, no indebtedness shall be incurred by the issuance of general obligation bonds of the district or by any contract by which the district agrees to repay as general obligations or other obligations constituting a "general obligation debt by loan in any form", as such term is used in section 6 of article XI of the state constitution, of the district to the federal government, the state, a political subdivision, or a person over a term not limited to the then current fiscal year any project costs advanced thereby under any contract for the acquisition or improvement of the facilities or any interest in the facilities, or for any project, advanced by the issuance of securities of such a political subdivision or person to defray any cost of the project or of the facilities or an interest in the project or facilities acquired and becoming a part of the facilities of the district, or otherwise advanced, unless a proposal for issuing the district's general obligation bonds or of incurring an indebtedness by the district by making such a contract is submitted to the electors of the district and is approved by a majority of such electors voting on the proposal at an election held for that purpose in accordance with this article.
C.R.S. § 37-50-124