Section 611.1055  Routine Monitoring Requirements for CWSs That Serve 1,000 or Fewer People Using Only Groundwater

a)         General

1)         This Section applies to CWS suppliers that use only ground water (except ground water under the direct influence of surface water, as defined in Section 611.102) and which serve 1,000 or fewer people.

2)         Following any total coliform-positive sample taken under the provisions of this Section, the supplier must comply with the repeat monitoring requirements and E. coli analytical requirements in Section 611.1058.

3)         Once all monitoring required by this Section and Section 611.1058 for a calendar month has been completed, the supplier must determine whether any coliform treatment technique triggers specified in Section 611.1059 have been exceeded.  If any trigger has been exceeded, the supplier must complete assessments as required by Section 611.1059.

b)         Monitoring Frequency for Total Coliforms.  The monitoring frequency for total coliforms is one sample per month, except as provided for under subsections (c) through (f).

c)         Transition to Subpart AA.  The Agency must perform a special monitoring evaluation during each sanitary survey to review the status of the supplier's system, including the distribution system, to determine whether the system is on an appropriate monitoring schedule.  After the Agency has performed the special monitoring evaluation during each sanitary survey, the Agency may, by a SEP issued under Section 611.110, modify the supplier's monitoring schedule, as necessary.  Alternatively, the Agency may allow the supplier to stay on its existing monitoring schedule, consistent with the provisions of this Section.  The Agency may not allow a supplier to begin less frequent monitoring under the special monitoring evaluation unless the supplier has already met the applicable criteria for less frequent monitoring in this Section.

d)         Criteria for Reduced Monitoring

1)         The Agency may, by a SEP, reduce the monitoring frequency from monthly monitoring to no less than quarterly monitoring if the supplier is in compliance with Agency-certified operator provisions and demonstrates that it meets the criteria in subsections (d)(1)(A) through (d)(1)(C).  A supplier that loses its certified operator must return to monthly monitoring the month following that loss.

A)        The supplier has a clean compliance history for a minimum of 12 months.

B)        The most recent sanitary survey shows the supplier is free of sanitary defects (or has an approved plan and schedule to correct them and is in compliance with the plan and the schedule), has a protected water source, and meets Agency-approved construction standards.

C)        The supplier meets at least one of the following criteria:

i)          An annual site visit by the Agency that is equivalent to a Level 2 assessment or an annual Level 2 assessment by a party approved by the Agency and correction of all identified sanitary defects (or an approved plan and schedule to correct them and is in compliance with the plan and schedule).

ii)         Cross connection control, as approved by the Agency.

iii)        Continuous disinfection entering the distribution system and a residual in the distribution system in accordance with criteria specified by the Agency.

iv)        Demonstration of maintenance of at least a 4-log removal or inactivation of viruses as provided for under Section 611.803(b)(3).

v)         Other equivalent enhancements to water system barriers as approved by the Agency.

2)         This subsection (d)(2) corresponds with 40 CFR 141.855(d)(2), which USEPA has marked "reserved".  This statement maintains structural consistency with the corresponding federal provision.

e)         Return to Routine Monthly Monitoring Requirements.  A supplier on quarterly monitoring that experience any of the events in subsections (e)(1) through (e)(4) must begin monthly monitoring the month following the event.  The supplier must continue monthly monitoring until it meets the reduced monitoring requirements in subsection (d).

1)         The supplier triggers a Level 2 assessment or two Level 1 assessments in a rolling 12-month period.

2)         The supplier has an E. coli MCL violation.

3)         The supplier has a coliform treatment technique violation.

4)         The supplier has two Subpart AA monitoring violations in a rolling 12- month period.

f)         Additional Routine Monitoring the Month Following a Total Coliform-Positive Sample.  A supplier collecting samples on a quarterly frequency must conduct additional routine monitoring the month following one or more total coliform-positive samples (with or without a Level 1 treatment technique trigger).  A supplier must collect at least three routine samples during the next month, except that the Agency may, by a SEP, waive this requirement if the conditions of subsection (f)(1), (f)(2), or (f)(3) are met.  A supplier may either collect samples at regular time intervals throughout the month or may collect all required routine samples on a single day if samples are taken from different sites.  A supplier must use the results of additional routine samples in coliform treatment technique trigger calculations.

1)         The Agency may, by a SEP, waive the requirement to collect three routine samples the next month in which the supplier's system provides water to the public if the Agency, or an agent approved by the Agency, performs a site visit before the end of the next month in which the supplier's system provides water to the public.  Although a sanitary survey need not be performed, the site visit must be sufficiently detailed to allow the Agency to determine whether additional monitoring or any corrective action is needed.  The Agency cannot approve an employee of the supplier to perform this site visit, even if the employee is an agent approved by the Agency to perform sanitary surveys.

2)         The Agency may, by a SEP, waive the requirement to collect three routine samples the next month in which the supplier's system provides water to the public if the Agency has determined why the sample was total coliform-positive and has established that the supplier has corrected the problem or will correct the problem before the end of the next month in which the supplier's system serves water to the public.  In this case, the Agency must document this decision to waive the following month's additional monitoring requirement in writing, have it approved and signed by the supervisor of the Agency official who recommends such a decision, and make this document available to USEPA and the public.  The written documentation must describe the specific cause of the total coliform-positive sample and what action the supplier has taken or will take to correct this problem.

3)         The Agency may not waive the requirement to collect three additional routine samples the next month in which the supplier's system provides water to the public solely on the grounds that all repeat samples are total coliform-negative.  If the Agency determines that the supplier has corrected the contamination problem before the supplier takes the set of repeat samples required in Section 611.1058, and all repeat samples were total coliform-negative, the Agency may, by a SEP, waive the requirement for additional routine monitoring the next month.

BOARD NOTE:  Derived from 40 CFR 141.855.

(Source:  Amended at 44 Ill. Reg. 6996, effective April 17, 2020)