S.C. Code § 49-17-1410
The collection of the assessment shall not be defeated, when the proper notices have been given, by reason of any defect in the proceedings occurring prior to the order of the clerk of the court confirming the final report of the viewers but such order or orders shall be conclusive and final that all prior proceedings were regular and according to law, unless they were appealed from. If on appeal the court shall deem it just and proper to release any person or to modify his assessment or liability it shall in no manner affect the rights and legal position of any person other than the appellant and the failure to appeal from the order of the clerk of the court within the time specified shall be a waiver of any illegality in the proceedings and the remedies provided for in this chapter shall exclude all other remedies.
S.C. Code § 49-17-1410