C.R.S. § 32-11-539

(1) Such tax shall be levied immediately after the issuance of any general obligation securities issued in accordance with the provisions of this article, at the times and in the manner provided by law, and annually thereafter until all of the securities and the interest thereon have been fully discharged. (2) Such tax may be first levied after the district, acting by and through the board, has contracted to sell any securities but before their issuance.