a) Modifications to Pending Applications.

Prior to a final Agency decision on a permit application for an NPDES permit or a sludge generator or sludge user permit, the applicant may propose modifications to the application in accordance with the Act and regulations adopted under the Act without any additional fee becoming due, unless the proposed modifications would cause additional fees to be due under Section 325.205.

b) Modifications to Existing Permits.

1. 1) If a requested modification to an existing NPDES permit causes a change in the applicable fee categories under Section 325.205 that results in an increase in the required fee, the permittee must pay to the Agency the amount of the increase, prorated for the number of months remaining before the next July 1, before the modification is granted. [415 ILCS 5/12.5(c)] For purposes of calculating the prorated fee due under this subsection (b)(1), partial months will be rounded down to the nearest whole month.
2. 2) If a requested modification to an existing sludge generator or sludge user permit causes a change in the applicable fee categories under Section 325.205 that results in an increase in the required fee, the permittee must pay to the Agency the amount of the increase, prorated for the number of months remaining before the next July 1, before the modification is granted. For purposes of calculating the prorated fee due under this subsection (b)(2), partial months will be rounded down to the nearest whole month.
3. c) If modifications to a permit application for an individual NPDES permit or a sludge generator or sludge user permit are received by the Agency from the applicant within 90 days after the date of a permit denial by the Agency, and if the modifications would allow approval of the application, a permit will be issued without additional fees becoming due under this Part, unless the proposed modifications cause an increase in the required fee under Section 325.205. If the modifications cause an increase in the fees due under Section 325.205, the applicant shall submit the additional fee to the Agency with the modification.
4. d) Except in those cases in which specified conditions of an individual NPDES permit or sludge generator or sludge user permit have been appealed to the Illinois Pollution Control Board in accordance with Section 40 of the Act, modifications received by the Agency more than 90 days after the date of a permit denial by the Agency shall be considered new applications subject to the fees specified in Section 325.205.