Tenn. Code Ann. § 7-21-404

The legislative branch of the unified government may establish and name such special service districts, as in its judgment, may be necessary or appropriate for the exercise within such district of any one (1) or more of the public corporation rights or powers of the unified government not then being exercised for the benefit of all citizens of the county. All tax levies in special service districts shall be made with due regard for services rendered in the special service districts. The boundaries of special service districts need not be contiguous and may overlap or be coextensive with the boundaries of other special service districts.