Neb. Rev. Stat. § 15-211

A city of the primary class may, by ordinance, require any and all lots or pieces of ground within the city or within its extraterritorial zoning jurisdiction to be drained or filled so as to prevent stagnant water or any other nuisance accumulating thereon. Upon the failure of the owners of such lots or pieces of ground to fill or drain the lots or pieces when so required, the city council may cause such lots or pieces of ground to be drained or filled, and the cost and expenses thereof shall be levied upon the property so filled or drained and collected as a special assessment.