Idaho Code § 43-1912

Any district issuing bonds under this act for the acquisition, construction, reconstruction, improvement, betterment or extension of any works, shall have the right to appropriate, apply or expend the revenue of the works for the following purposes: (a) to pay when due all bonds and interest thereon, for the payment of which the revenue is or shall have been pledged, charged or otherwise encumbered, including reserves therefor; (b) to provide for all expenses of operation, maintenance, replacement and depreciation of the works, including reserves therefor; (c) to pay and discharge notes, bonds or other obligations and interest thereon, not issued under this act for the payment of which the revenue of the works may have been pledged, charged or encumbered; (d) to pay and discharge notes, bonds or other obligations and interest thereon which do not constitute a lien, charge or encumbrance on the revenue of such works, which may have been issued for the purpose of financing the acquisition, construction, reconstruction, improvement, betterment or extension of the works; and (e) provide a reserve for improvements to the works. Unless and until full and adequate provision has been made for the foregoing purposes, no district shall have the right to transfer the revenue of works to its general fund.