S.C. Code Ann. § 5-41-130: Sales and use tax; imposition and termination.

(A) If the sales and use tax is approved in the referendum, the tax is imposed on the first of May following the date of the referendum. If the reimposition of an existing sales and use tax imposed pursuant to this chapter is approved in the referendum reimposing the tax, the new tax is imposed immediately following the termination of the earlier imposed tax and the reimposed tax terminates on the applicable thirtieth of April, not to exceed seven years from the date of reimposition. If the certification is not timely made to the Department of Revenue, the imposition is postponed for twelve months.

(B) The tax terminates the final day of the maximum time period specified for the imposition.

(C)(1) Amounts collected in excess of the required net proceeds must first be applied, if necessary, to complete a project for which the tax was imposed, if applicable.

(2) If funds still remain after first using the funds as described in item (1) and the tax is reimposed, the remaining funds must be used to fund any projects approved by the voters in the referendum to reimpose the tax, in priority order as the projects appeared on the enacting ordinance.

(3) If funds still remain after first using the funds as described in item (1) and the tax is not reimposed, the remaining funds must be used for the purposes pursuant to Section 5-41-120(C)(1). These remaining funds only may be expended for the purposes pursuant to Section 5-41-120(C)(1) following an ordinance specifying the authorized purpose or purposes for which the funds will be used.