When Does a Dam Need a Permit in South Carolina?
The threshold question in South Carolina is whether the dam is regulated at all, and the answer turns on a size test paired with a consequence test. Both are below, from S.C. Code Ann. §§ 49-11-110 et seq. and S.C. Code Regs. 72-1 through 72-9.
Which dams are exempt — and the conjunction that decides it
Under § 49-11-120(4)(a) a dam is outside the Act if it is less than 25 feet in height AND has less than 50 acre-feet impounding capacity. Both conditions must hold.
North Carolina's equivalent exemption, G.S. 143-215.25A(a)(6), uses the same two numbers with or: under 25 feet or under 50 acre-feet. South Carolina uses and.
So a 20-foot dam impounding 200 acre-feet meets North Carolina's size threshold (it is under 25 feet) but fails South Carolina's (it is not under 50 acre-feet). An engineer carrying a rule of thumb across the state line gets this backwards, and it is the single most consequential difference between the two programs.
The exemption is also conditional either way: the Department may still regulate a smaller dam where hazard potential is such that failure may cause loss of human life.
Other exclusions
- Dams owned or operated by federal agencies.
- Dams licensed by FERC or the NRC, or under USACE authority.
- Dams of the South Carolina Public Service Authority.
- Dams where a transportation department maintains the road that is the primary downstream hazard (R.72-2).
- Dams the Department determines pose no significant downstream threat.
Approval to build, enlarge, repair or remove
§ 49-11-200(A): construction of a new dam or reservoir, or the enlargement, removal or repair of an existing one, may not begin until the owner has applied for and obtained written approval from the Department. Application requirements are in § 49-11-210, and for a high or significant hazard dam the application must include a fully developed emergency action plan.
Scope. General information about South Carolina dam safety regulation, read from primary sources and current as of 2026-08-28. Not an engineering opinion about any specific structure and not legal advice. Requirements change when the legislature amends the Dams and Reservoirs Safety Act or the rules are revised — confirm against the current text of S.C. Code Ann. §§ 49-11-110 et seq. and S.C. Code Regs. 72-1 through 72-9, and contact the South Carolina Department of Environmental Services (SCDES) for a determination that binds.