Ohio Rev. Code § 6111.52: Level three credible data activities.

The director of environmental protection shall use only level three credible data to conduct any of the following activities:

(A) Developing, reviewing, and revising use designations in water quality standards;

(B) Developing a statewide water quality inventory or other water assessment report;

(C) Identifying, listing, and delisting waters of the state for the purpose of section 303(d) of the Federal Water Pollution Control Act;

(D) Determining whether a water of the state is supporting its designated use or other classification;

(E) Establishing a total maximum daily load for a water of the state.