Tennessee Code Title 13. Public Planning and Housing § 13-7-603

(a) Except as otherwise provided in subsection (b), an ordinance, resolution, regulation, rule, or other requirement of any type that prohibits, effectively prohibits, or otherwise regulates the use of property as a short-term rental unit shall not apply to property if the property was being used as a short-term rental unit by the owner of the property prior to the enactment of the ordinance, resolution, regulation, rule, or other requirement by the local governing body. The ordinance, resolution, regulation, rule, or other requirement in effect at the time the property began being used as a short-term rental unit is the law that governs the use of the property as a short-term rental unit until the property is sold, transferred, ceases being used as a short-term rental unit for a period of thirty (30) continuous months, or has been in violation of a generally applicable local law three (3) or more separate times as provided by § 13-7-604. For purposes of this subsection (a), an ordinance, resolution, regulation, rule, or other requirement is in effect at the time it is lawfully enacted by the local governing body and not the time in which it is introduced for consideration by the local governing body.

(b) Notwithstanding subsection (a), an ordinance, resolution, regulation, rule, or other requirement of any type enacted prior to January 1, 2014, that prohibits or effectively prohibits the use of property as a short-term rental unit may apply to any property within a local governing body's jurisdiction, regardless of the property's existing use. However, this subsection (b) applies only to ordinances, resolutions, regulations, rules, or other requirements that expressly limit the period of time a residential dwelling may be rented, and does not apply to ordinances, resolutions, regulations, rules, or other requirements that generally prohibit commercial activity or the renting of residential dwellings to transients.