Mont. Code Ann. § 85-2-417

Any person constructing the necessary ditches, aqueducts, or flumes and making the payments or tenders hereinbefore provided is entitled to the use of so much of the surplus water as said ditches, flumes, or aqueducts have the capacity to carry and for which payment or tender is made and may institute and maintain any appropriate action at law or in equity for the enforcement of such right or recovery of damages arising from a failure to deliver or wrongful diversion of the same.