S.C. Code Ann. § 15-9-720: Service on unknown parties by publication for certain real property actions.

(A) For the purposes of this section, "court" means a court, judge, clerk of court, master-in-equity, special referee, or judge of probate of competent jurisdiction in the county where the action is pending.

(B)(1) A court shall grant an order allowing a party with an interest in or lien on a parcel of real property subject to a partition action, mortgage foreclosure action, or other action affecting the property's title to serve by publication any unknown party to the action and who has an interest in or lien on the real property, any such legal notice as will accomplish the underlying purposes set forth in this section, if the:

(a) residence of the unknown party cannot, with a reasonably diligent effort, be ascertained by the plaintiff; and

(b) plaintiff presents an affidavit to the court stating he has been unable to ascertain the residence of the unknown party after making a reasonably diligent effort.

(2) A court order allowing a party to serve an unknown party by publication must require the party serving by publication to publish the service once a week for three weeks in a newspaper of general circulation in the county where the property is situated. Service by publication under this section is equal to personal service on the unknown party.

(C) A party may accomplish service by publication pursuant to this section for multiple units in a single horizontal property regime by consolidating the services into a single service that identifies each apartment included in the action based on the apartment's description in the master deed. This consolidated service must comply with the other requirements of this section and other applicable statutes, including the requirement that publication must take place once a week for three weeks in a newspaper of general circulation in the county where the property is situated.