Indian-owned lands passing to non-Indian ownership shall be assessed for construction costs and the first assessment shall be due on December 31 of the year that the Indian title is extinguished. The construction costs against this land will be established as provided by section 5 of the act of September 26, 1961 (75 Stat. 680). The annual per acre assessment rate will be determined by dividing the established construction cost per acre into forty equal payments. “B” lands will also be assessed for reservoir construction costs in the annual per-acre rate as established in the Designation Report dated August 1962. Assessments against this land will continue until the entire established construction costs shall have been repaid to the U.S. Treasury. Landowners may pay at any time the total of the then remaining indebtedness. Under the act of March 10, 1928 (45 Stat. 210), the unpaid charges stand as a lien against the lands until paid.