S.C. Code § 6-11-2110
The commissioners of election for the county in which the referendum is held shall certify the results of the election to the governing body of the district. The question presented in referendum shall be considered approved if at least two-thirds of the qualified electors of the district voting in the referendum vote in favor of it. The commissioners of election shall also cause the certificate of results of the referendum to be filed with the clerk of court for the county in which the district is located within five days of the date of the certification. The results of the referendum and the validity of those actions taken precedent to it are not open to question except by action instituted within thirty days from the filing of the certificate of results.
S.C. Code § 6-11-2110