S.C. Code § 12-37-235
Each county and municipality in this State may charge the owners of all real property exempt from ad valorem taxation under the provisions of items (2), except property of the State, counties, municipalities, school districts and other political subdivisions where such property is used exclusively for public purposes, (3), except public libraries, and (4) of subsection (A) of Section 12-37-220 of the 1976 Code, which is located within their respective boundaries, reasonable fees for fire protection; provided, that no fees may be charged by a county for protection or service provided to such owners by a municipality.
All such fees shall be based on the protection and services provided and which are maintained in whole or in part by funds from ad valorem taxes. No fees shall exceed the amount of taxes that would be levied on any of the subject property for any one service if the subject property were subject to ad valorem taxation.
S.C. Code § 12-37-235