South Carolina Code 46-35-40. Service of citation
If the party resides within the county, service may be made by leaving a copy of the citation, together with a copy of the petition, at the residence of the party between the hours of eight in the morning and six in the evening with some person not less than eighteen years of age. If at the time of attempted service between said hours no such person can be found at the residence of the party, service may be made by mail. If the party does not reside within the county, service may be made by mail, if he resides or has his office at a place where there is a delivery service by mail and, if not or if his residence is not known, service may be made by posting a copy of the citation, together with a copy of the petition, in a conspicuous place on the property at least twenty days before the date specified in the citation.