Ohio Revised Code Title LXI. Water Supply Sanitation Ditches § 6111.56

(A) If the source or sources of a pollutant causing an impairment of a water of the state are unknown, the water of the state may be identified and listed under section 303(d) of the Federal Water Pollution Control Act. However, the director of environmental protection shall continue to monitor the water of the state to determine the source or sources of the impairment before a total maximum daily load is established for the water of the state pursuant to that section.

(B) The director shall not include a water of the state on a list established under section 303(d) of the Federal Water Pollution Control Act or establish a total maximum daily load for a water of the state if the failure of the water of the state to comply with an applicable water quality standard results solely from the existence of a naturally occurring condition or conditions.

(C) The director shall establish narrative water quality standards where numerical criteria cannot be established or to supplement numerical criteria.