Mont. Code Ann. § 7-12-4201

All costs and expenses incurred in the acquisition or construction of any improvements specified in part 41 in any improvement district or incurred in the issuance of the bonds or warrants of the district, including incidental expenses, shall be paid for by special improvement district bonds or warrants. The city or town council shall provide for making payments for improvements in any special improvement district by the method provided in 7-12-4204 and 7-12-4205.