Mont. Code Ann. § 85-7-2116

Whenever the irrigable area of the lands in an irrigation district or subdistrict has been determined and confirmed, the owner or holder of title or evidence of title to lands in the district or subdistrict, during the period when any bonds are issued and outstanding, may not have the taxable acreage of the owner's or titleholder's lands fixed or adjudicated in the manner provided by 85-7-1841 through 85-7-1845 in a manner or to an extent as to reduce the acreage subject to the payment of the bonds or interest or in a manner as to affect the security of the bonds or interest on the bonds.