Heat pumps, air conditioning systems, skirting, steps, decks, septic tanks, wells, and driveways built or installed after the home is delivered to the construction site are not considered a part of the delivered home and are taxed separately from the home. The sale of these items to, or the purchase of these items by, the person who will build or supply and install them is subject to the tax.
S.C. Code Regs. § 117-335.5