Conn. Gen. Stat. § 7-334

The central city and any one or more towns, cities or boroughs within a metropolitan area may join to form a metropolitan district for the performance of any one or more functions, services or works which any of such towns, cities or boroughs is by special act or general statute authorized to perform. The jurisdiction of the metropolitan district for the performance of such functions, services or works as it may perform shall be coterminous with the area of the respective towns, cities and boroughs comprising such district.