Mont. Code § 85-1-213
The department may institute in any court any actions, suits, and special proceedings necessary to enable it to acquire, own, and hold title to lands for dam sites, reservoir sites, water rights, rights-of-way for diversion and distributing canals, and lateral ditches and other means of distribution of water and may also in any court institute, maintain, and prosecute to final determination actions, suits, and special proceedings necessary to have the water rights adjudicated upon any stream or source of water supply from which is derived the water for the reservoir, diversion and distributing canals, lateral ditches, and other means of distribution of the water. The department may join owners of waters appropriated by a person, association, or corporation from the streams of the state so that adjudication may be had of all surplus water upon all the streams and sources of water supply of a project constructed by the department. All costs and expenses of the actions, suits, or special proceedings shall be paid by the department out of funds provided under this chapter.
§ 85-1-213, MCA