35 Ill. Adm. Code 6110.611.641
State-Only MCLs
Section 611
TITLE 35: ENVIRONMENTAL PROTECTION
SUBTITLE F: PUBLIC WATER SUPPLIES
CHAPTER I: POLLUTION CONTROL BOARD
PART 611 PRIMARY DRINKING WATER STANDARDS
SECTION 611.641 STATE-ONLY MCLS
Section 611.641 State-Only MCLs
a) An analysis of substances for the purpose of determining
compliance with the State-only MCLs of Section 611.310 must be made as follows:
1) The Agency must issue a SEP requiring CWS suppliers utilizing
surface water sources to collect samples during the period of the year when
contamination by pesticides is most likely to occur. The Agency must require
the supplier to repeat these analyses at least annually.
2) The Agency must issue a SEP requiring CWS suppliers utilizing
only groundwater sources to collect samples at least once every three years.
b) If the result of an analysis made under subsection (a)
indicates that the level of any contaminant exceeds its State-only MCL, the CWS
supplier must report to the Agency within seven days and initiate three
additional analyses within one month.
c) When the average of four analyses made under subsection (a),
rounded to the same number of significant figures as the MCL for the substance
in question, exceeds the State-only MCL, the CWS supplier must report to the
Agency and give notice to the public under Subpart T of this Part. Monitoring
after public notification must be at a frequency designated by the Agency and
must continue until the MCL has not been exceeded in two successive samples or
until a monitoring schedule as a condition to a variance, adjusted standard, or
enforcement action becomes effective.
d) Analysis made to determine compliance with the State-only MCLs
of Section 611.310 must be made in compliance with the appropriate methods
specified in Section 611.645.
BOARD NOTE: This provision now
applies only to State-only MCLs. This Section originally derived from 40 CFR
141.24(a) through (e), which USEPA removed and reserved.