Mont. Code Ann. § 20-9-142

By the later of the first Tuesday in September or within 30 calendar days after receiving certified taxable values, the county superintendent shall place before the board of county commissioners the final adopted budget of the district. It is the duty of the board of county commissioners, as provided in 7-6-4036, to fix and levy on all the taxable value of all the real and personal property within the district all district and county taxation required to finance, within the limitations provided by law, the final budget.