Indiana Code Title 36. Local Government § 36-9-27-84

Sec. 84. (a) After letting a contract for the construction, reconstruction, or maintenance of a drain, the board shall determine the full cost of the construction, reconstruction, or maintenance, including the contract price, incidental expenses, damages, interest on any bonds issued under section 94 of this chapter, and attorney's fees, if any.  The board shall then apportion this cost to the tracts of land assessed in proportion to the benefit percentage previously assigned to each tract.  If the contract is for work on an urban drain, the board shall also designate each tract that is assessed as rural land or urban land.

(b) When determining and apportioning the full cost of construction or reconstruction under this section, the board may include for contingencies a reasonable sum not in excess of ten percent (10%) of the full cost.

(c) An improved or unimproved lot or tract of land that is benefited by the construction, reconstruction, or maintenance of a regulated drain shall be assessed each year for that construction, reconstruction, or maintenance in an amount fixed by the board.