Section 611.740  General Requirements

a)         This Subpart R contains National Primary Drinking Water Regulations.  These Subpart R requirements for filtration and disinfection apply in addition to those applying under Subpart B.  This Subpart R applies to a Subpart B system supplier serving 10,000 or more persons, unless this Subpart R specifies otherwise.  This Subpart R establishes or extends treatment techniques in lieu of MCLs for certain contaminants:  Giardia lamblia, viruses, heterotrophic plate count bacteria, Legionella, Cryptosporidium, and turbidity.  A Subpart B system supplier serving 10,000 or more persons must treat its source water complying with the treatment techniques in this Subpart R and are in addition to those in Section 611.220.  The treatment techniques in this Subpart R consist of installing and properly operating water treatment processes reliably achieving two objectives:

1)         At least 99 percent (2-log) removal of Cryptosporidium between a point where the raw water is not subject to recontamination by surface water runoff and a point downstream before or at the first customer for a supplier applying filtration treatment; and

2)         Compliance with the profiling and benchmark requirements under Section 611.742.

b)         A PWS supplier subject to this Subpart R complies with subsection (a) if it complies with the applicable filtration requirements in Section 611.250 or 611.743 and the disinfection requirements in Sections 611.240 and 611.742.

c)         A supplier must not begin constructing an uncovered finished water storage facility. 

d)         A supplier deciding to significantly change its disinfection practice, as Section 611.742 (c)(1)(A) through (c)(1)(D) describes, must obtain Agency approval in a SEP before of the Agency prior to making the significant change.

BOARD NOTE:  This Section derives from 40 CFR 141.170.

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