In a residential lease, what responsibilities does a landlord have to maintain his rental unit?

A landlord must keep his rental unit in compliance with applicable building and house codes.
A landlord must make repairs that keep his rental unit in a fit and habitable condition.
A landlord must keep all common areas of the premises in a reasonably safe condition. If the premises contain more than four units, the landlord must keep the common areas in a reasonably clean condition, too.
A landlord must ensure his rental unit has running water, adequate heat, and reasonable amounts of hot water.
A landlord must keep the following in working order: (1) electrical, (2) gas, (3) plumbing, (4) sanitary, (5) heating, (6) ventilating, (7) air conditioning, and (8) other facilities and appliances, including elevators, provided by him. A tenant and landlord can come to an arrangement in the lease where the tenant can perform landlord’s duties or other specified repairs, maintenance tasks, alterations, or remodeling but only if such arrangement does not serve the purpose of landlord evading his obligations under the South Carolina Residential Landlord Tenant Act.