Illinois Administrative Code › Title 35 - ENVIRONMENTAL PROTECTION › Part 611 - PRIMARY DRINKING WATER STANDARDS › Subpart AA - REVISED TOTAL COLIFORM RULE › Section 611.1058 - Repeat Monitoring and E. coli Requirements

Current through Register Vol. 48, No. 28, July 12, 2024
a) Repeat Monitoring
1) If a sample taken under Sections
				611.1054
				through
				611.1057
				is total coliform-positive, the supplier must collect a set of repeat samples
				within 24 hours after being notified of the positive result. The supplier must
				collect no fewer than three repeat samples for each total coliform-positive
				sample found. The Agency may, by a SEP, extend the 24-hour limit on a
				case-by-case basis if the supplier has a logistical problem in collecting the
				repeat samples within 24 hours that is beyond its control. Alternatively, the
				Agency may implement criteria for the supplier to use in lieu of case-by-case
				extensions. In the case of an extension, the Agency must specify how much time
				the supplier has to collect the repeat samples. The Agency cannot waive the
				requirement for a supplier to collect repeat samples in subsections (a)(1)
				through (a)(3).
2) The supplier
				must collect all repeat samples on the same day, except that the Agency may, by
				a SEP, allow a supplier with a single service connection to collect the
				required set of repeat samples over a three-day period or to collect a larger
				volume repeat samples in one or more sample containers of any size, as long as
				the total volume collected is at least 300 ml.
3) The supplier must collect an additional
				set of repeat samples in the manner specified in subsections (a)(1) through
				(a)(3) if one or more repeat samples in the current set of repeat samples is
				total coliform-positive. The supplier must collect the additional set of repeat
				samples within 24 hours after being notified of the positive result, unless the
				Agency extends the limit as provided in subsection (a)(1). The supplier must
				continue to collect additional sets of repeat samples until either total
				coliforms are not detected in one complete set of repeat samples or the
				supplier determines that a coliform treatment technique trigger specified in
				Section
				611.1059(a)
				has been exceeded as a result of a repeat sample being total coliform-positive
				and notifies the Agency. If a trigger identified in Section
				611.1059
				is exceeded as a result of a routine sample being total coliform-positive, the
				supplier is required to conduct only one round of repeat monitoring for each
				total coliform-positive routine sample.
4) After a supplier collects a routine sample
				and before it learns the results of the analysis of that sample, if the
				supplier collects another routine sample from within five adjacent service
				connections of the initial sample, and the initial sample, after analysis, is
				found to contain total coliforms, then the system may count the subsequent
				sample as a repeat sample instead of as a routine sample.
5) Results of all routine and repeat samples
				taken under Sections
				611.1054
				through 611.1058 not invalidated by the Agency must be used to determine
				whether a coliform treatment technique trigger specified in Section
				611.1059
				has been exceeded.