S.C. Code Ann. § 12-37-2690

A municipality may by contract authorize the county to assess and collect the municipal tax on motor vehicles. When so contracted, the provisions hereof shall be applicable to the municipal tax on vehicles. In such cases the duplicate and receipt above provided for shall also reflect the amount of municipal tax. A municipality that does not contract shall by ordinance provide for the date that taxes due on motor vehicles for each tax year are to be paid. All statutes providing for the collection of taxes shall be applicable to such municipal tax.