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
Universal Citation: 35 IL Admin Code ยง 611.1058
Current through Register Vol. 48, No. 38, September 20, 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.
b) Escherichia coli (E. coli) Testing
1) If any
routine or repeat sample is total coliform-positive, the supplier must analyze
that total coliform-positive culture medium to determine if E. coli are
present. If E. coli are present, the supplier must notify the Agency by the end
of the day when the supplier is notified of the test result, unless the
supplier is notified of the result after the Agency office is closed and the
Agency does not have either an after-hours phone line or an alternative
notification procedure, in which case the supplier must notify the Agency
before the end of the next business day.
2) The Agency has the discretion to allow a
supplier, on a case-by-case basis, to forego E. coli testing on a total
coliform-positive sample if that supplier assumes that the total
coliform-positive sample is E. coli-positive. Accordingly, the supplier must
notify the Agency as specified in subsection (b)(1) and the provisions of
Section 141.63(c) apply.
BOARD NOTE: Derived from 40 CFR 141.858.
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