Nothing contained in sections 16-673 to 16-677 shall change or in any way affect existing franchises or existing contracts between any city and any company, corporation, or individual for furnishing the city or its inhabitants with light, power, heat, or water. The mayor and city council shall levy a sufficient tax to pay for such light, power, heat, or water supply in accordance with the terms of such existing contracts, not exceeding four and nine-tenths cents on each one hundred dollars upon the taxable value of all the taxable property in such city in any one year for any one of the purposes.
Neb. Rev. Stat. §§ 16-678