Tenn. Code § 69-5-817
It is the duty of the trustee to collect the assessments along with other taxes upon the lands, which shall be credited to the account of the drainage district; and it is the duty of the county trustee, within ten (10) days after any drainage tax is delinquent, to give written notice to the party to whom the tract or tracts on which taxes are delinquent is assessed that the tax is delinquent, and that a penalty of ten percent (10%) will accrue on the delinquency as provided in this part. No additional amount shall be taxed against the party assessed to cover any attorney's fees in case of suit brought necessary to collect the taxes; the attorney's fees shall be paid out of the penalty, and shall not in any case exceed the penalty.
T.C.A. § 69-5-817