Tenn. Code § 8-4013
For the purpose of providing further funds with which to aid the defraying of costs of the retirement herein provided, all county officials participating in the retirement system shall contribute each month, from his or her total monthly compensation realized from serving as such county official, four per cent (4%) commencing July 1, 1968, if in office on that date, or from the date he became a county official, if subsequent to that date. This contribution shall be paid to the chairman of the retirement board or other official designated by him and shall be placed in the state treasury for use in making the payments herein provided and shall become a part of the retirement fund.
Any participating county official who fails to make the required monthly contribution and becomes delinquent for more than sixty (60) days, will be subject to the action of the retirement board with respect to continued participation in the system.
T.C.A. § 8-4013