Illinois Administrative Code
Title 35 - ENVIRONMENTAL PROTECTION
Part 611 - PRIMARY DRINKING WATER STANDARDS
Subpart W - INITIAL DISTRIBUTION SYSTEM EVALUATIONS
Section 611.921 - Standard Monitoring
Universal Citation: 35 IL Admin Code ยง 611.921
Current through Register Vol. 48, No. 38, September 20, 2024
a) Standard Monitoring Plan. A supplier's standard monitoring plan must comply with subsections (a)(1) through (a)(4). The supplier must prepare and submit its standard monitoring plan to the Agency according to the appropriate of the schedules provided in Section 611.920(c).
1) The supplier's standard monitoring plan
must include a schematic of its distribution system (including distribution
system entry points and their sources, and storage facilities), with notes
indicating locations and dates of all projected standard monitoring, and all
projected Subpart I compliance monitoring.
2) The supplier's standard monitoring plan
must include justification of standard monitoring location selection and a
summary of data the supplier relied on to justify standard monitoring location
selection.
3) The supplier's
standard monitoring plan must specify the population served and its system type
(i.e., that it is a Subpart B or groundwater system).
4) The supplier must retain a complete copy
of its standard monitoring plan submitted under this subsection (a), including
any Agency modification of the plan, for as long as the supplier is required to
retain its IDSE report under subsection (c)(4).
b) Standard Monitoring
1) The supplier must monitor as indicated in
the applicable of subsections (b)(1)(A) through (b)(1)(P), subject to the
limitations of subsections (b)(1)(Q) and (b)(1)(R). The supplier must collect
dual sample sets at each monitoring location. One sample in the dual sample set
must be analyzed for TTHM. The other sample in the dual sample set must be
analyzed for HAA5. The supplier must conduct one monitoring period during the
peak historical month for TTHM levels or HAA5 levels or the month of warmest
water temperature. The supplier must review available compliance, study, or
operational data to determine the peak historical month for TTHM or HAA5 levels
or warmest water temperature.
A) A Subpart B
system supplier that serves fewer than 500 persons and which operates a
consecutive system must collect samples once each calendar year during the peak
historical month: one near an entry point to the distribution system and one at
a high TTHM location, for a total of two samples during each monitoring
period.
B) A Subpart B system
supplier that serves fewer than 500 persons and which does not operate a
consecutive system must collect samples once each calendar year during the peak
historical month: one at a high TTHM location and one at a high HAA5 location,
for a total of two samples during each monitoring period.
C) A Subpart B system supplier that serves
500 to 3,300 persons and which operates a consecutive system must collect
samples four times each calendar year (once every 90 days): one near an entry
point to the distribution system and one at a high TTHM location, for a total
of two samples during each monitoring period.
D) A Subpart B system supplier that serves
500 to 3,300 persons and which does not operate a consecutive system must
collect samples four times each calendar year (once every 90 days): one at a
high TTHM location and one at a high HAA5 location, for a total of two samples
during each monitoring period.
E) A
Subpart B system supplier that serves 3,301 to 9,999 persons must collect
samples four times each calendar year (once every 90 days): one at a location
in the distribution system that represents the average residence time, two at
high TTHM locations, and one at a high HAA5 location, for a total of four
samples during each monitoring period.
F) A Subpart B system supplier that serves
10,000 to 49,999 persons must collect samples six times each calendar year
(once every 60 days): one near an entry point to the distribution system, two
at locations in the distribution system that represent the average residence
time, three at each TTHM location, and two at high HAA5 locations, for a total
of eight samples during each monitoring period.
G) A Subpart B system supplier that serves
50,000 to 249,999 persons must collect samples six times each calendar year
(once every 60 days): three near entry points to the distribution system, four
at locations in the distribution system that represent the average residence
time, five at high TTHM locations, and four at high HAA5 locations, for a total
of 16 samples during each monitoring period.
H) A Subpart B system supplier that serves
250,000 to 999,999 persons must collect samples six times each calendar year
(once every 60 days): four near entry points to the distribution system, six at
locations in the distribution system that represent the average residence time,
eight at high TTHM locations, and six at high HAA5 locations, for a total of 24
samples during each monitoring period.
I) A Subpart B system supplier that serves
1,000,000 to 4,999,999 persons must collect samples six times each calendar
year (once every 60 days): six near entry points to the distribution system,
eight at locations in the distribution system that represent the average
residence time, ten at high TTHM locations, and eight at high HAA5 locations,
for a total of 32 samples during each monitoring period.
J) A Subpart B system supplier that serves
5,000,000 or more persons must collect samples six times each calendar year
(once every 60 days): eight near entry points to the distribution system, ten
at locations in the distribution system that represent the average residence
time, 12 at high TTHM locations, and ten at high HAA5 locations, for a total of
40 samples during each monitoring period.
K) A groundwater system supplier that serves
fewer than 500 persons and which operates a consecutive system must collect
samples once each calendar year during the peak historical month: one near an
entry point to the distribution system and one at a high TTHM location, for a
total of two samples during each monitoring period.
L) A groundwater system supplier that serves
fewer than 500 persons and which does not operate a consecutive system must
collect samples once each calendar year during the peak historical month: one
at a high TTHM location and one at a high HAA5 location, for a total of two
samples during each monitoring period.
M) A groundwater system supplier that serves
500 to 9,999 persons must collect samples four times each calendar year (once
every 90 days): one at a high TTHM location and one at a high HAA5 location,
for a total of two samples during each monitoring period.
N) A groundwater system supplier that serves
10,000 to 99,999 persons must collect samples four times each calendar year
(once every 90 days): one near an entry point to the distribution system, one
at a location in the distribution system that represents the average residence
time, two at high TTHM locations, and two at high HAA5 locations, for a total
of six samples during each monitoring period.
O) A groundwater system supplier that serves
100,000 to 499,999 persons must collect samples four times each calendar year
(once every 90 days): one near an entry point to the distribution system, one
at a location in the distribution system that represents the average residence
time, three at high TTHM locations, and three at high HAA5 locations, for a
total of eight samples during each monitoring period.
P) A groundwater system supplier that serves
500,000 or more persons must collect samples four times each calendar year
(once every 90 days): two near an entry point to the distribution system, two
at locations in the distribution system that represent the average residence
time, four at high TTHM locations, and four at high HAA5 locations, for a total
of 12 samples during each monitoring period.
Q) A dual sample set (i.e., a TTHM and an
HAA5 sample) must be taken at each monitoring location during each monitoring
period.
R) The "peak historical
month", for the purposes of subsections (b)(1)(A), (b)(1)(B), (b)(1)(K), and
(b)(1)(L), means the month with the highest TTHM or HAA5 levels or the warmest
water temperature.
2) The
supplier must take samples at locations other than the existing Subpart I
monitoring locations. Monitoring locations must be distributed throughout the
distribution system.
3) If the
number of entry points to the distribution system is fewer than the specified
number of entry point monitoring locations, excess entry point samples must be
equally replaced at high TTHM and HAA5 locations. If there is an odd extra
location number, the supplier must take a sample at a high TTHM location. If
the number of entry points to the distribution system is more than the
specified number of entry point monitoring locations, the supplier must take
samples at the entry points to the distribution system that have the highest
annual water flows.
4) The
supplier's monitoring under this subsection (b) may not be reduced under the
provisions of Section
611.500, and the
Agency may not reduce the supplier's monitoring using the provisions of Section
611.161.
c) IDSE Report. A supplier's IDSE report must include the elements required in subsections (c)(1) through (c)(4). The supplier must submit its IDSE report to the Agency according to the applicable of the schedules set forth in Section 611.920(c).
1) The supplier's IDSE report must include
all TTHM and HAA5 analytical results from Subpart I compliance monitoring and
all standard monitoring conducted during the period of the IDSE as individual
analytical results and LRAAs presented in a tabular or spreadsheet format
acceptable to the Agency. If changed from the supplier's standard monitoring
plan submitted under subsection (a), the supplier's report must also include a
schematic of the supplier's distribution system, the population served, and
system type (Subpart B system or groundwater system).
2) The supplier's IDSE report must include an
explanation of any deviations from the supplier's approved standard monitoring
plan.
3) The supplier must
recommend and justify Subpart Y compliance monitoring locations and timing
based on the protocol in Section
611.925.
4) The supplier must retain a complete copy
of its IDSE report submitted under this Section for ten years after the date on
which the supplier submitted the supplier's report. If the Agency modifies the
Subpart Y monitoring requirements that the supplier recommended in its IDSE
report or if the Agency approves alternative monitoring locations under Section
611.161, the supplier must keep a copy of the Agency's notification on file for
ten years after the date of the Agency's notification. The supplier must make
the IDSE report and any Agency notification available for review by the Agency
or the public.
BOARD NOTE: Derived from 40 CFR 141.601.
Disclaimer: These regulations may not be the most recent version. Illinois may have more current or accurate information. We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on the state site. Please check official sources.
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