218.335 Local governmental entity; authority to charge interest on overdue payments.—A local governmental entity may impose an interest penalty on any amount due and owing to it from another local governmental entity if payment of the amount is not made within 10 working days after the required time authorized by interlocal agreement. The rate of interest that must be imposed is the rate established under s. 55.03. This section does not apply to payments due from the state or any of its agencies.