DHEC issues wastewater construction permits for collection systems. However, if a proposed line meets the definition of a service connection or service line, a DHEC permit is not required. DHEC only permits main lines. Generally speaking, a service line is a line or group of lines serving a single building. While a more thorough definition is found in Regulation 61-67.100.D.44, the single building example is typical. Where two service lines come together, the downstream line is defined as a main line or main sewer. Main lines need to be permitted by DHEC. See chart for an illustration.
Special Cases. For alternative collection systems (septic tank effluent pumping systems), the main line actually begins at the tank/pump point, even though the tank/pump may only be serving one home. Double service lines for residential development are not considered main lines (and don't need permitting), however the entity owning main line must be responsible for the common service line that serves both homes. A line that is serving one building, but has the reasonable ability to serve other properties or buildings would not be considered a service line. In any case, you can contact DHEC to decide if your particular case requires a DHEC permit.