S.C. Code § 49-17-540
The engineer and viewers shall personally examine the land in the district and classify it with reference to the benefit it will receive from the construction of the levee, ditch, drain or watercourse or other improvement. In the case of drainage the degree of wetness of the land, its proximity to the ditch or a natural outlet and the fertility of the soil and its effect upon health conditions in the district shall be considered in determining the amount of benefit it will receive by the construction of the ditch. The land benefited shall be separated in five classes. The land receiving the highest benefit shall be designated "Class A"; that receiving the next highest benefit, "Class B"; that receiving the next highest benefit, "Class C"; that receiving the next highest benefit, "Class D," and that receiving the smallest benefit, "Class E." The holding of any one landowner need not necessarily be all in one class but the number of acres in each class shall be ascertained, though its boundary need not be marked on the ground or shown on the map. The total number of acres owned by one person in each class and the total number of acres benefited shall be determined. The total number of acres of each class in the entire district shall be obtained and presented in tabulated form.
S.C. Code § 49-17-540