Tenn. Code Ann. § 67-4-2913

After June 20, 2006, no county shall be authorized to enact an impact fee on development or a local real estate transfer tax by private or public act. In addition, this part shall be the exclusive authority for local governments to adopt any new or additional adequate facilities taxes on development. However, this part shall not be construed to prevent a municipality or county from exercising any authority to levy or collect similar development taxes or impact fees granted by a private act that was in effect prior to June 20, 2006, or from revising the dedicated use and purpose of a tax on new development from public facilities to public school facilities. A county levying a development tax or impact fee by private act on June 20, 2006, shall be prohibited from using the authority provided in this part so long as the private act is in effect.