1. a) A person that has been issued an NPDES Permit must not discharge any contaminant in its effluent in excess of the standards and limitations for that contaminant in its permit.

2. b) A person must not discharge any pollutant subject to, or that contributes to or threatens to cause a violation of, any applicable federal or State water quality standard, effluent standard, guideline, or other limitation, promulgated under the CWA or the Act, unless a limitation for the pollutant is in an applicable NPDES Permit. However, the Agency may, by permit condition, provide that the permittee may discharge pollutants present in its water supply intake sources in concentrations not greater than the concentrations in the intake sources, or which are added in trace amounts by normal domestic water usage.

   BOARD NOTE: Section 304.141(b) was declared invalid in Peabody Coal Co. v. PCB, 3 Ill. App. 3d 5 (5^th District, 1976) and declared valid in U.S. Steel v. PCB, 52 Ill. App. 3d 1 (2d District, 1977).

3. c) The standards of this Chapter apply to thermal discharges unless, after public notice and opportunity for a public hearing, in compliance with section 316 of the CWA, applicable federal regulations, and procedures in 35 Ill. Adm. Code 106.Subpart K, the Board has determined that different standards apply to a particular thermal discharge.

(Source: Amended at 47 Ill. Reg. 4601, effective March 23, 2023)