Section 611.1056  Routine Monitoring Requirements for Subpart B Systems That Serve 1,000 or Fewer People

a)         General

1)         The provisions of this Section apply to a Subpart B system supplier that serves 1,000 or fewer people.

2)         Following any total coliform-positive sample taken under the provisions of this Section, a 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, a 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.

4)         Seasonal System Suppliers

A)        All seasonal system suppliers must demonstrate completion of an Agency-approved start-up procedure, which may include a requirement for start-up sampling prior to serving water to the public.

B)        The Agency may, by a SEP, exempt any seasonal system supplier from some or all of the requirements for seasonal system suppliers if the supplier's entire distribution system remains pressurized during the entire period that the supplier's system is not operating.

b)         Routine Monitoring Frequency for Total Coliforms.  A Subpart B system supplier (including a consecutive system supplier) must monitor monthly.  A supplier may not reduce monitoring.

c)         Unfiltered Subpart B System Suppliers.  A Subpart B system supplier that does not practice filtration in compliance with Subparts B, R, X, and Z must collect at least one total coliform sample near the first service connection each day that the turbidity level of the source water, measured as specified in Section 611.532(b), exceeds 1 NTU.  When one or more turbidity measurements in any day exceed 1 NTU, the supplier must collect this coliform sample within 24 hours after the first exceedance, unless the Agency determines that the supplier, for logistical reasons outside the supplier's control, cannot have the sample analyzed within 30 hours after collection, and the Agency identifies an alternative sample collection schedule.  Sample results from the coliform monitoring required by this subsection (c) must be included in determining whether the coliform treatment technique trigger in Section 611.1059 has been exceeded.

BOARD NOTE:  Derived from 40 CFR 141.856.

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