S.C. Code § 12-45-390
When an area of a county is annexed to another county, property taxes shall be levied based upon the last assessment of property values and levied according to the millage of the annexing county and shall be prorated between the two counties for the taxable year.
Any delinquent taxes on property in the area annexed shall be executed upon by the annexing county and the actual amount of the tax due and the amount of the penalties due at the time of annexation, upon collection, shall be paid to the county from which the area was annexed. All costs of execution and collection shall be deducted and retained by the annexing county.
If the sale of property for payment of delinquent taxes is necessary, the sale shall be held in the annexing county in the same manner as all other such sales are held.
S.C. Code § 12-45-390