Tenn. Code Ann. § 68-9-109: Contracts.

(a) The department is empowered to enter into, execute and perform all contracts for services or property, or both, necessary or proper to the execution of the purposes of this chapter and, to this end, may enter into any contract with any county or municipality, or both, jointly, for the use, loan or purchase of any property, real or personal, belonging to the county or municipality, and suitable for the execution of the powers conferred in this chapter, and to make any arrangement for the care, treatment, observation and supervision of eligible patients, under this chapter that may appear proper to the commissioner.

(b) Any contract authorized in this chapter shall comply with all requirements of the law in executing the contract and shall be subject to the budgetary process of the general assembly.