Tenn. Code Ann. § 7-33-115: Tax levy to meet payments not met by assessments

(a) It is the duty of the legislative body of the municipality to levy an ad valorem tax upon all of the taxable property in the municipality to pay the principal and interest of the bonds as they become due, or to pay such part or parts of the principal and interest of the bonds as are not provided for by the assessments levied and actually collected and in the treasury of the municipality set apart for the payment of such bonds and interest.

(b) Such tax shall be in addition to all other taxes that such municipality is by law authorized to levy.