Mont. Code § 85-7-1841
Whenever any lot, tract, or parcel of land has been heretofore or may hereafter be included within the boundaries of any public irrigation district formed under the laws of this state and the acreage thereof fixed and stated in the decree for the creation of said district or in any other proceeding relating thereto is fixed at a greater number of acres than actually exist within such lot, tract, or parcel of land or at a greater number of acres than can be irrigated from the reclamation system of said district or whenever, from any action or proceeding by or on behalf of said district or its commissioners, any such lot, tract, or parcel of land included therein has been or is about to be assessed from a greater acreage than exists therein or can be irrigated from the reclamation system of said district, the owner or holder of title or evidence of title to said lands, as defined by the irrigation district acts, may have the taxable acreage contained therein fixed and adjudicated as provided for by 85-7-1841 through 85-7-1845. However, if any bonds have been issued with the approval and pursuant to confirmation by the court then no proceeding for the determination of the acreage shall be allowed to alter or reduce in any manner the acreage subject to the lien of such bonds, in principal or interest, or of the taxes or assessments to meet the interest or principal thereof while such bonds or the interest thereon are unpaid in whole or in part. Such proceeding may still be allowed to correct or determine acreage subject to taxes or assessments for maintenance and current expenses and insofar as the latter only are to be affected.
§ 85-7-1841, MCA