If a metropolitan utilities district supplies water at retail to residents of a city or village other than a city of the metropolitan class or residents of a sanitary and improvement district, whether or not such city, village, or sanitary and improvement district is within the district boundaries, such city, village, or sanitary and improvement district and metropolitan utilities district shall have power and authority to enter into a contract to obtain the use of facilities and services of the water utility of such district in order to collect from the residents supplied water by the district sewer use or rental fees or charges for other utility services for such city, village, or sanitary and improvement district in the same manner and to the same extent as is provided for such services to cities of the metropolitan class by sections 14-2134 to 14-2136. No utility service under this section shall be discontinued for nonpayment of charges for unrelated services.