Antidegradation provisions describe the conditions under which water quality may be lowered in surface waters. Existing beneficial uses must be maintained and protected. Further, water quality better than that needed to protect existing beneficial uses must be maintained unless lower quality is deemed necessary to allow important economic or social development (existing beneficial uses must still be protected).
Provisions addressing antidegradation are in the Water Quality Standards chapter of the Ohio Administrative Code (OAC Chapter 3745-1). Within that chapter, rule 3745-1-54 addresses antidegradation provisions for wetlands and rule 3745-1-05 addresses antidegradation provisions for other surface waters of the state.