1. a) Notice to POTW. The Agency must notify the POTW if, on the basis of pollutant removal capability reports received pursuant to Section 310.350(c) or other information available to it, the Agency determines:

   1. 1) That one or more of the discharge limits revisions made by the POTW, or the POTW itself, no longer meets the requirements of this Subpart; or
   2. 2) That such discharge limit revisions are causing or significantly contributing to a violation of any conditions or limits contained in the POTW's NPDES permit. A revised discharge limit is significantly contributing to a violation of the POTW's permit if it satisfies the definition of pass through or interference as defined in Section 310.110.
2. b) Corrective action. If appropriate corrective action is not taken within a reasonable time, not to exceed 60 days unless the POTW or an affected industrial user demonstrates that a longer time period is reasonably necessary to undertake the appropriate corrective action, the Agency must either withdraw such discharge limits or require modifications in the revised discharge limits.

3. c) Public notice of withdrawal or modification. The Agency must not withdraw, modify, or revise discharge limits unless it first notifies the POTW and all industrial users to whom revised discharge limits have been applied, and made public in writing the reasons for such withdrawal or modification and provided an opportunity for public hearing. Following such notice and withdrawal or modification, all industrial users to whom revised discharge limits had been applied must be subject to the modified discharge limits or the discharge limits prescribed in the applicable categorical pretreatment standards as appropriate and must achieve compliance with such limits within a reasonable time, not to exceed the period of time prescribed in the applicable categorical pretreatment standard.

   BOARD NOTE: Derived from 40 CFR 403.7(f)(4) (2003), as modified to reflect NRDC v. USEPA, 790 F.2d 289 (3d Cir. 1986).

(Source: Amended at 47 Ill. Reg. 5083, effective March 23, 2023)