After any such contract shall have been duly executed, as herein provided, the board of directors shall, in accordance with the provisions of such contract, adopt a resolution that a tax be assessed and levied upon all the taxable property in the district. Such tax shall be within the limitation herein provided and shall be levied annually on each dollar of the taxable valuation in the district until the contract obligations have been paid, or a sufficient fund has been accumulated to pay the same. The resolution shall state the purpose of such levy and the amount thereof. A certified copy thereof shall be mailed to the county auditor of each county in the district. Upon the receipt of such resolution or as soon thereafter as county levies are made, such county auditor shall spread the levy specified in such resolution for the current year and annually thereafter as required by such resolution.