S.C. Code Ann. § 27-40-630 – Wrongful failure to provide essential services

(a) If the landlord is negligent or wilful in failing to provide essential services as required by the rental agreement or Section 27-40-440, the tenant may give written notice to the landlord specifying the breach and may:
1. (1) procure reasonable amounts of the required essential services during the period of the landlord's noncompliance and deduct their actual and reasonable cost from the rent; or
2. (2) recover damages based upon the diminution in the fair-market rental value of the dwelling unit and reasonable attorney's fees.
(b) If the tenant proceeds under this section, he may not proceed under Section 27-40-610 as to that breach.
(c) Under no circumstances should this section be interpreted to authorize the tenant to make repairs on the rental property and deduct the cost of the repairs from rent. In the event that the tenant unlawfully acts without the landlord's consent and authorizes repairs, any mechanic's lien arising therefrom shall be unenforceable.
(d) Rights of the tenant under this section do not arise until he has given notice to the landlord and the landlord fails to act within a reasonable time or if the condition was caused by the deliberate or negligent act or omission of the tenant, a member of his family, or other person on the premises with the tenant's permission or who is allowed access to the premises by the tenant.