Nebraska Revised Statute 17-912
The councils or boards of the cities or villages issuing such joint bonds for the erection of such plant shall levy annually a sufficient tax to maintain and operate and extend such plant and to provide for the payment of interest on, and principal of, any bonds that may have been issued as herein provided.
Laws 1921, c. 192, § 2, p. 713;
C.S.1922, § 4395;
C.S.1929, § 17-602;
R.S.1943, § 17-912.