Section 611.325  Microbiological Contaminants

a)         A supplier complies with the MCL for E. coli for samples taken under Subpart AA, unless any of the conditions identified in subsections (a)(1) through (a)(4) occur.  For purposes of public notification under Subpart V, violating the MCL may pose an acute risk to human health.

1)         The supplier has an E. coli-positive repeat sample following a total coliform-positive routine sample.

2)         The supplier has a total coliform-positive repeat sample following an E. coli-positive routine sample.

3)         The supplier fails to take all required repeat samples following an E. coli-positive routine sample.

4)         The supplier fails to test for E. coli when any repeat sample tests positive for total coliform.

b)         A supplier must determine whether it complies with the MCL for E. coli in subsection (a) for each month during which the supplier must monitor for total coliforms.

c)         USEPA identified the best technology, treatment techniques, or other means for complying with the MCL maximum contaminant level for E. coli in subsection (a):

1)         Protecting wells from fecal contamination by appropriate placement and construction;

2)         Maintaining RDC throughout the distribution system;

3)         Properly maintaining the distribution system, including appropriate pipe replacement and repair procedures, main flushing programs, properly operating and maintaining storage tanks and reservoirs, cross-connection control, and continually maintaining positive water pressure in all parts of the distribution system;

4)         Filtering and disinfecting surface water, as Subparts B, R, X, and Z describe, or disinfecting groundwater, as Subpart S describes, using a strong oxidant like chlorine, chlorine dioxide, or ozone; or

5)         For a system using groundwater, complying with permit conditions the Agency imposes under the USEPA-endorsed Illinois wellhead protection program.

BOARD NOTE:  USEPA requires the supplier to comply with the wellhead protection program.  The Illinois program operates under the Illinois Groundwater Protection Act [415 ILCS 55].  USEPA endorses, rather than approves, state groundwater protection programs and periodically reviews those programs with the state.  See “Final Comprehensive State Ground Water Protection Program Guidance”, USEPA, Office of the Administrator, doc. no. EPA 100-R-93-001 (Dec. 1992), at p. 1-21 & n. 4 and pp. 1-24 and 1-25.  Section 18(a) of the Act requires a supplier to operate under an Agency-issued permit.  Other Illinois laws may require a permit for a groundwater well.  E.g., Sections 5(b), 5b, and 6 of the Illinois Water Well Construction Code [415 ILCS 30/5(b), 5b, and 6].

d)         USEPA identifies the technology, treatment techniques, or other means in subsection (c) as affordable technology, treatment techniques, or other means available to suppliers serving 10,000 or fewer people for achieving compliance with the for E. coli MCL in subsection (a).

BOARD NOTE:  This subsection (a) derives from 40 CFR 141.63(c), subsection (b) derives from the second sentence of 40 CFR 141.63(d), and subsection (c) derives from 40 CFR 141.63(e).  The Board omits 40 CFR 141(a) and (b) and the first sentence of 40 CFR 141.63(d), which expired by their own terms March 31, 2016.

(Source:  Amended at 47 Ill. Reg. 16486, effective November 2, 2023)