The governing body of a city may enter a written annexation agreement with the governing body of another city regarding the annexation of property located within the extraterritorial zoning or subdivision regulation authority of the cities under chapter 40-47 or 40-48. An agreement is binding on the governing bodies of the cities for the term of the agreement unless the governing bodies agree otherwise or unless determined otherwise by an administrative law judge in accordance with this chapter. An agreement may not have a term greater than twenty years.