Michigan Compiled Laws, Chapter 141. Municipal Financing § 141.122

(a) After provision for the payment for the next succeeding period of all current expenses of administration and operation and the current expenses for that period for maintenance as may be necessary to preserve the public improvement in good repair and working order.

(b) There shall be next set aside a sum sufficient to provide for the payment of the principal of and the interest upon all bonds payable from those revenues, as and when the bonds become due and payable. This account shall be designated “bond and interest redemption account”. In the event that the revenues of any operating year over and above those necessary for the operation and maintenance expenses shall be insufficient to pay the principal of and interest on the bonds maturing in any operating year, then an additional amount sufficient to pay the principal and interest shall be set aside out of the revenues of the next succeeding operating year, after provision for the expenses of operation and maintenance. In respect to the allocation and use of money in the bond and interest redemption account, due recognition shall be given as to priority rights, if any, between different issues or series of outstanding bonds. The public corporation may provide by ordinance that a reasonable excess amount shall be set aside in the bond and interest redemption account from time to time so as to produce and provide a reserve to meet any possible future deficiencies.

(c) Next there shall be set aside, in the manner and priority provided by the ordinance, the sum or sums necessary for the additional accounts as may be required.