Section 553.530 - Disposition of funds received(1) All sums of money received by a district in payment of any assessment shall be kept in a separate fund for each subdistrict from which the assessment is collected. All funds remaining unexpended in any construction fund after the payment of all costs incurred for the construction of works in any subdistrict shall be paid into the improvement fund for such subdistrict, and any funds remaining on hand in any maintenance and operation fund for any year for any subdistrict shall likewise be paid into the improvement fund of that subdistrict.(2) The district shall maintain a general fund in which shall be kept all funds received by the district for paying the general overhead and other expenses of the district. The district shall pay into the general fund such portion of each of the special assessments levied against lands within subdistricts as is necessary to pay the general expenses and overhead of the district.