Tenn. Code Ann. § 68-221-210: Authority to levy and collect other charges

(a) The municipality collecting the user's fee shall have the authority to fix, levy and collect fees, rents, tolls or other charges in an amount necessary to provide for the maintenance and operation of sewage treatment works and payment of any indebtedness.

(b) This authority shall be in addition to any other authority to set like fees or to levy taxes pursuant to any other statute or authority granted by the state.