Neb. Rev. Stat. §§ 23-3627
The county board shall, within thirty days after the effective date of the annexation, submit to the annexing city or village a written accounting of all assets and liabilities, contingent or fixed, of the county with regard to the sewerage disposal system and plant or plants. The annexation of the sewerage disposal system and plant or plants shall be effective thirty days after the effective date of the ordinance annexing the territory unless some later date is specified in the ordinance and is agreed to by the annexing city or village and the county. If the validity of the ordinance annexing the territory is challenged by a proceeding in a court of competent jurisdiction, the effective date of the annexation shall be thirty days after the final determination of the validity of the ordinance. The county shall continue in possession of the sewerage disposal system and plant or plants and shall continue to conduct all affairs with regard to the sewerage disposal system and plant or plants until the effective date of the annexation.
Neb. Rev. Stat. §§ 23-3627