S.C. Code § 5-31-10
Any municipal corporation of this State having power to construct and operate a plant for water supply or any person contemplating the laying of pipes for supplying water to a municipal corporation or to a community of citizens may lay water pipes for the purpose of carrying water on or under the bed of any nontidal navigable stream of this State and, with the approval of the county authorities in any county, on or under any highway of such county. Such pipes shall be so laid as not to interfere with the free use of such highway or the navigation of such streams by boats to the same extent that they would be navigable if such pipes were not laid.
Every such municipality or person, having laid such pipes, shall keep them in repair.
S.C. Code § 5-31-10