S.C. Code Ann. § 6-1-40: Interstate extension of water and sewer systems.

No water or sewage system owned or operated by a county, municipality, special purpose district, or political subdivision created, organized, or existing under the laws of any other state may be extended, leased, or operated in the unincorporated area of any county of this State unless the county governing body wherein the system is proposed to be extended, leased, or operated has by ordinance approved and authorized the extension, lease, or operation.