The Treasurer of the District shall immediately notify the treasurer of each member municipality of the amount of that municipality's assessment and the member municipality shall add such assessment to its own budget and shall assess such tax as is necessary to raise the amount of the assessment. The amount of the assessment in each member municipality shall be paid to the Treasurer of the District in accordance with the schedule of payments adopted by the Board. If any member municipality shall fail to pay when due any assessment against it by the District, it shall incur the maximum penalty allowed by law plus interest at the rate set by the Board. Such penalty and interest, together with the amount due, court costs, and reasonable attorney's fees of the District may be recovered by the District in a civil action under this section, notwithstanding the availability of any other remedy available to the District. Prior to the commencement of any new fiscal year, the Board of Commissioners shall determine, by resolution, the interest rate for that fiscal year, which in no case shall exceed one and one-half percent per month.