The department, as a member of the tri-institutional Winnebago Mental Health Institute, Winnebago County Asylum, and Sunny View Sanatorium sewer agreement in Winnebago County, is authorized to furnish and charge for water and sewerage services to business and dwelling units located in the privately owned area lying west of the Winnebago Mental Health Institute and bounded on the west by the railroad properties and on the north, east, and south by the grounds of the Winnebago Mental Health Institute, together with any dwelling or other units located on the railroad-owned and state-owned property adjacent to this area.