Neb. Rev. Stat. § 16-6,104

For the purpose of paying the cost of any sanitary sewer mains or water mains constructed in a connection district created under section 16-6,102 , the mayor and city council may spend funds accumulated in any sanitary sewer or water department surplus funds of the city. The connection fees collected by any such city for properties connecting to such sanitary sewer mains or water mains shall be paid into the sanitary sewer or water department surplus fund to replenish such funds for the construction costs.