K.S.A. 12-812

If such city deems it necessary to enlarge, improve or extend any waterworks system, or part thereof (so condemned), the governing body is hereby empowered to issue for said purpose bonds to such an amount as may be fixed by ordinance and authorized by the electors at the election hereinbefore provided for, or at any subsequent special election or elections called therefor, which said bonds shall be issued according to law.