S.C. Code § 12-37-2630
When a motor vehicle is first taxable in a county the owner or person having control of the vehicle shall make a property tax return of it within forty-five days, as referenced in Section 56-3-210, and prior to applying for a license. The return shall be made to the auditor of the county in which the owner or person having control of the motor vehicles resides. If the motor vehicle is used in a business the return shall be made to the auditor of the county in which the motor vehicle is situated, that being the county and city of principal use of the vehicle. The return shall be signed under oath and shall set forth the county, school district, special or tax district, and municipality in which the vehicle is principally used.
S.C. Code § 12-37-2630