Nebraska Revised Statute 17-909
The council or board of such city or village shall levy annually a sufficient tax to maintain, operate and extend any such plant, and to provide for the payment of the interest on the principal of any bonds that may have been issued as provided in section 17-908.
Laws 1921, c. 192, § 1, p. 712;
C.S.1922, § 4394;
C.S.1929, § 17-601;
R.S.1943, § 17-909.