S.C. Code § 59-21-30
No school in any school district shall continue open a longer period of time than that fixed by (a) the board of trustees in the district in which such school is located or (b) the county board of education in any county which may operate under a county unit plan. No school shall receive any benefits under the provisions of Section 59-21-20 which does not have the minimum average daily attendance for the previous scholastic year, or for the current scholastic year, fixed in the schedules below.
In three-teacher high schools the minimum average daily attendance shall be 48; in four-teacher high schools the minimum average daily attendance shall be 68; in five-teacher high schools the minimum average daily attendance shall be 90; in six-teacher high schools the minimum average daily attendance shall be 114; in seven-teacher high schools the minimum average daily attendance shall be 140; in eight-teacher high schools the minimum average daily attendance shall be 168; in nine-teacher high schools the minimum average daily attendance shall be 198; in ten-teacher high schools the minimum average daily attendance shall be 230; in eleven-teacher high schools the minimum average daily attendance shall be 264; in twelve-teacher high schools the minimum average daily attendance shall be 300; and in all high schools with more than twelve teachers the minimum average daily attendance shall be 26 pupils for each teacher.
In one-teacher elementary schools the minimum average daily attendance shall be 17; in two-teacher elementary schools the minimum average daily attendance shall be 36; in three-teacher elementary schools the minimum average daily attendance shall be 60; in four-teacher elementary schools the minimum average daily attendance shall be 84; in five-teacher elementary schools the minimum average daily attendance shall be 110; in six-teacher elementary schools the minimum average daily attendance shall be 138; in seven-teacher elementary schools the minimum average daily attendance shall be 168; in eight-teacher elementary schools the minimum average daily attendance shall be 200; in nine-teacher elementary schools the minimum average daily attendance shall be 234; and in all elementary schools with more than nine teachers the minimum average daily attendance shall be 26 pupils per teacher. In addition to the number of teachers a district is entitled to under the above schedule, a district shall receive benefits to pay additional teachers, high or elementary, according to the excess average daily attendance in each school, such excess to be added together by level. The high school excess average daily attendance shall be divided by 26 and the elementary excess average daily attendance by 26. Each district shall receive benefits for the salaries resulting from such excess, provided that the school board of trustees shall not employ a teacher in any school based on the average daily attendance of another school within the district.
S.C. Code § 59-21-30