S.C. Code Ann. § 12-36-2570 — Time when tax payment due; monthly report

(A) The taxes imposed under the provisions of this chapter, except as otherwise provided, are due and payable in monthly installments on or before the twentieth day of the month following the month in which the tax accrues.
(B) On or before the twentieth day of each month, every person on whom the taxes under this chapter are imposed shall render to the department, on a form prescribed by it, a true and correct statement showing, by location, the gross proceeds of wholesale and retail sales of his business, and sales price of the property purchased for storage, use, or consumption in this State, together with other information the department may require.
(C) At the time of making a monthly report, the person shall compute the taxes due and pay to the department the amount of taxes shown to be due. A return is considered to be timely filed if the return is mailed and has a postmark dated on or before the date the return is required by law to be filed.
(D) The department may permit the filing of returns every twenty-eight days. These returns must be filed within twenty days following the period covered by the return.
(E) The department may enter into an agreement with a taxpayer which allows the taxpayer to remit the tax on statistical factors as set forth in the agreement. This method of reporting only applies to purchases by the taxpayer for its use, storage, or consumption, and not to purchases by the taxpayer for resale.