1. a) Notify the Agency that the owner or operator intends to make a demonstration under this Section when submitting the groundwater monitoring results required under Section 615.208.
2. b) Submit a report to the Agency that demonstrates that a source other than a facility or unit owned or operated by the owner or operator caused the groundwater standard to be exceeded, or that the groundwater standard was exceeded due to an error in sampling, analysis or evaluation. Such report must be included with the next submission of groundwater monitoring results required under Section 615.208; and
3. c) Continue to monitor in compliance with the groundwater monitoring program established under Sections 615.205, 615.206, and 615.207.

If the groundwater sampling required under Section 615.207 shows that a groundwater standard has been exceeded, it is presumed that contamination from the facility or unit that is being monitored is responsible for the standard being exceeded. An owner or operator may overcome that presumption by making a demonstration that a source other than the facility or unit that is being monitored caused the exceedance or that the exceedance resulted from error in sampling, analysis, or evaluation. In making the demonstration, the owner or operator must:

(Source: Amended at 47 Ill. Reg. 7581, effective May 16, 2023)