Mont. Code Ann. § 85-7-1925

Whenever, in the judgment of the commissioners of any irrigation district, it is necessary for the proper measurement, distribution, or apportionment of the water of the district to install lock boxes, headgates, or other devices for the distribution of water at the point where any lateral is taken out of a main ditch or canal or at a point where any sublateral is taken out of a lateral for further division or distribution of water, they shall have the authority to procure and install the same and to assess the cost thereof against the lands affected thereby.