S.C. Code § 31-3-1040
The legislative delegation of each of the counties in the regional housing authority, the commissioners of the regional housing authority and the legislative delegation of each such additional county or counties shall by resolution declare that there is a need for the inclusion of such additional county or counties in the area of operation of the regional housing authority only if (a) the legislative delegation of each such additional county or counties finds that unsanitary or unsafe inhabited dwelling accommodations exist in such county or there is a shortage of safe and sanitary dwelling accommodations in such county available to persons of low income at rentals they can afford and (b) the legislative delegation of each of the counties then included in the area of operation of the regional housing authority, the commissioners of the regional housing authority and the legislative delegation of each such additional county or counties find that the regional housing authority would be a more efficient or economical administrative unit to carry out the purposes of this chapter and Chapter 11 if the area of operation of the regional housing authority is increased to include such additional county or counties.
In determining whether dwelling accommodations are unsafe or unsanitary the legislative delegation of a county shall take into consideration the safety and sanitation of dwellings, the light and air space available to the inhabitants of such dwellings, the degree of overcrowding, the size and arrangement of the rooms and the extent to which conditions exist in such dwellings which endanger life or property by fire or other causes.
S.C. Code § 31-3-1040