To provide additional funds for the payment of the principal of, interest on, and other charges in connection with bonds issued under the provisions of this article, in the event its anticipated revenue and funds are found to be insufficient therefor by order entered on its minutes each year that such tax is found necessary, a copy of which order shall be published for two consecutive weeks in a newspaper published in each county of the district thirty days before such levy is made by the board of supervisors, the district is also empowered to levy annually a special tax, not to exceed two mills upon all of the taxable property within such district, on or before the first Monday of September of each year and shall certify the levy to the boards of supervisors of the various counties in said district; and it shall be the duty of the boards of supervisors to make said levy on each tract of land or other property in said county, according to the assessed valuation thereof. Such taxes shall be collected by the tax collectors of the respective counties in said district, who shall deposit them in such depository as shall be selected by the board of directors of the district. Where bonds are issued payable wholly or partially from ad valorem taxes, it shall be the duty of the board of directors to levy a tax sufficient, together with pledged revenues other than the taxes authorized hereunder, to pay the bonds and the interest thereon as such bonds and interest become due, provided that in no event shall the tax levied exceed two mills. Any part of this levy lost through homestead exemption shall not be reimbursed by the state.