Neb. Rev. Stat. § 19-1402

The cost of purchasing, constructing, maintaining, and improving utilities under section 19-1401 may be defrayed by the levy of a tax of not to exceed three and five-tenths cents on each one hundred dollars upon the taxable value of all the taxable property in such city or village in any one year for a heating or lighting plant and of not to exceed two and one-tenth cents on each one hundred dollars upon the taxable value of all the taxable property in such city or village in any one year for an ice plant, or when such tax is insufficient for the purpose, the cost of such utilities may be defrayed by the issuance of bonds of the municipality.