S.C. Code Ann. § 48-1-85

(A) It is unlawful for a person to operate or float a houseboat on the waters of this State unless it has a marine toilet that discharges only into a holding tank. (B) As used in this section: (1) "Holding tank" means a container designed to receive and hold sewage and other wastes discharged from a marine toilet and constructed and installed in a manner so that it may be emptied only by pumping out its contents. (2) "Houseboat" means watercraft primarily used as habitation and not used primarily as a means of transportation. (3) "Marine toilet" includes equipment for installation on board a houseboat designed to receive, retain, treat, or discharge sewage. A marine toilet must be equipped with a holding tank. (C) When an owner of a houseboat having a marine toilet applies to the Department of Natural Resources for a certificate of title pursuant to Section 50-23-20, he shall certify in the application that the toilet discharges only into a holding tank. (D) Houseboat holding tanks may be emptied only by a pump-out system permitted by the South Carolina Department of Health and Environmental Control. (E) A person who violates this section is guilty of a misdemeanor and, upon conviction, must be fined not more than two hundred dollars for each day's violation or imprisoned not more than thirty days, or both. Effect of Amendment The 2007 amendment, in subsection (A), substituted "waters of this State unless it has a marine toilet that discharges" for "freshwaters of this State having a marine toilet unless it discharges"; and, in paragraph (B)(2), substituted "watercraft primarily used as habitation" for "a vessel which is used primarily as a residence".