In all cases of annexation under current Montana law, services must be provided according to a plan provided by the municipality as specified in 7-2-4732, except: (1) as provided in 7-2-4736; and (2) in first-class cities, when otherwise mutually agreed upon by the municipality and the real property owners of the area to be annexed.
Provision Of Services
Mont. Code Ann. § 7-2-4610, under Annexation by Petition.
Mont. Code Ann. § 7-2-4610