A Critical Area Line (CAL) is the boundary between the upland and the tidelands and coastal water critical areas, and any activities seaward of the CAL require a permit. CALs are determined by DHEC OCRM staff upon request and are valid for 5 years. A current CAL must be included with all permits that involve erosion control structures or docks with walkways that are 900' or greater over the critical area. CALs are also often required by local municipalities for building setback purposes. A CAL request can be submitted via ePermitting.