Whenever in any district any assessment has been levied and assessed upon land and remains unpaid in whole or in part, and in the judgment and opinion of the board it is for the best interest of the district or the landowners therein to issue bonds for the purpose of obtaining money to pay the costs of the proposed project, the indebtedness of the district, or any other lawful charge, or when a petition signed by the holders of title to more than one-fourth in assessed value of the land requesting it is filed with the secretary, the board shall by order entered upon its records call a special election to be held in the district. At the special election the question shall be submitted to the holders of title to assessed land whether or not bonds of the district shall be issued in an amount equal to the amount of the assessment, or the part of the assessment remaining unpaid. The amount shall be entered by the board in its records and stated in the order calling the special election.