S.C. Code Ann. § 58-5-390
A publicly or privately owned utility may not impose a tap fee, other fee, or a recurring maintenance fee of any nature or however described for the installation and maintenance of a fire sprinkler system that exceeds the actual costs associated with the water line to the system.
For purposes of this section, actual costs include direct labor, direct material, the necessity of increased capacity, and other direct charges associated with the separate fire sprinkler line. The direct costs must be documented by either an invoice or work order that specifically assigns the costs to the separate fire sprinkler line. Nothing in this section may be construed as requiring a utility to provide service to support a private fire protection system.