Sec. 2. (a) The board shall budget annually the necessary money to meet the probable expenses of operation and maintenance of the district, including the following:
(1) Repairs.
(2) Fees.
(3) Salaries.
(4) Depreciation on all depreciable assets.
(5) Rents.
(6) Supplies.
(b) Subject to any budget review and approval required under this chapter, the board may add not more than ten percent (10%) of the total for contingencies.