Ill. Admin. Code tit. 35 § 301.102
The General Assembly finds that pollution of the waters of this State constitutes a menace to public health and welfare, creates public nuisances, is harmful to wildlife, fish, and aquatic life, impairs domestic, agricultural, industrial, recreational, and other legitimate beneficial uses of water, depresses property values, and offends the senses [415 ILCS 5/11(a)(1)] . It is the purpose of these rules to designate the uses for which the various waters of the State will be maintained and protected; to prescribe the water quality standards required to sustain the designated uses; to establish effluent standards to limit the contaminants discharged to the waters; and to prescribe additional regulations necessary for implementing, achieving and maintaining the prescribed water quality. It is also the purpose of these rules to comply with Section 402 of the Clean Water Act.
Ill. Admin. Code tit. 35, § 301.102