Section 611.803  Treatment Technique Requirements for GWS Suppliers

a)         GWS Suppliers with Significant Deficiencies or Source Water Fecal Contamination

1)         The treatment technique requirements of this Section must be met by GWS suppliers when a significant deficiency is identified or when a groundwater source sample collected under Section 611.802(a)(3) is fecal indicator-positive.

2)         If directed by the Agency by a SEP, a GWS supplier with a groundwater source sample collected under Section 611.802(a)(2), (a)(4), or (b) that is fecal indicator-positive must comply with the treatment technique requirements of this Section.

3)         When a significant deficiency is identified at a Subpart B PWS that uses both groundwater and surface water or groundwater under the direct influence of surface water, the system must comply with provisions of this subsection (a) except in cases where the Agency determines that the significant deficiency is in a portion of the distribution system that is served solely by surface water or groundwater under the direct influence of surface water.

4)         Unless the Agency, by a SEP, directs the GWS supplier to implement a specific corrective action, the GWS supplier must consult with the Agency regarding the appropriate corrective action within 30 days after receiving written notice from the Agency of a significant deficiency, written notice from a laboratory that a groundwater source sample collected under Section 611.802(a)(3) was found to be fecal indicator-positive, or direction from the Agency that a fecal indicator-positive collected under Section 611.802(a)(2), (a)(4), or (b) requires corrective action.  For the purposes of this Subpart S, significant deficiencies include defects in design, operation, or maintenance, or a failure or malfunction of the sources, treatment, storage, or distribution system that the Agency determines to be causing, or have potential for causing, the introduction of contamination into the water delivered to consumers.

5)         Within 120 days (or earlier if directed by the Agency) after receiving written notification from the Agency of a significant deficiency, written notice from a laboratory that a groundwater source sample collected under Section 611.802(a)(3) was found to be fecal indicator-positive, or written notice from the Agency that a fecal indicator-positive sample collected under Section 611.802(a)(2), (a)(4), or (b) requires corrective action, the GWS supplier must do either of the following:

A)        It must have completed corrective action in accordance with any applicable plan review processes adopted by the Agency or with any SEP issued by the Agency, if any, including Agency-specified interim measures; or

B)        It must be in compliance with an Agency-approved corrective action plan and schedule, subject to the following conditions:

i)          Any subsequent modifications to an Agency-approved corrective action plan and schedule must also be approved by the Agency; and

ii)         If the Agency specifies interim measures for protection of the public health pending Agency approval of the corrective action plan and schedule or pending completion of the corrective action plan, the supplier must comply with those interim measures, as well as with any schedule specified by the Agency.

6)         Corrective Action Alternatives.  A GWS supplier that meets the conditions of subsection (a)(1) or (a)(2) must implement one or more of the following corrective action alternatives:

A)        It must correct all significant deficiencies;

B)        It must provide an alternate source of water;

C)        It must eliminate the source of contamination; or

D)        It must provide treatment that reliably achieves at least 4-log treatment of viruses (using inactivation, removal, or an Agency-approved combination of 4-log virus inactivation and removal) before or at the first customer for the groundwater source.

7)         Special Notice to the Public of Significant Deficiencies or Source Water Fecal Contamination

A)        In addition to the applicable public notification requirements of Section 611.902, a community GWS supplier that receives notice from the Agency of a significant deficiency or notification of a fecal indicator-positive groundwater source sample that is not invalidated by the Agency under Section 611.802(d) must inform the public served by the water system under Section 611.883(h)(6) of the fecal indicator-positive source sample or of any significant deficiency that has not been corrected.  The supplier must continue to inform the public annually until the significant deficiency is corrected or the fecal contamination in the groundwater source is determined by the Agency to be corrected under subsection (a)(5).

B)        In addition to the applicable public notification requirements of Section 611.902, a non-community GWS supplier that receives notice from the Agency of a significant deficiency must inform the public served by the water system in a manner approved by the Agency of any significant deficiency that has not been corrected within 12 months after being notified by the Agency, or earlier if directed by the Agency.  The supplier must continue to inform the public annually until the significant deficiency is corrected.  The information must include the following information:

i)          The nature of the significant deficiency and the date the significant deficiency was identified by the Agency;

ii)         The Agency-approved plan and schedule for correction of the significant deficiency, including interim measures, progress to date, and any interim measures completed; and

iii)        For a supplier with a large proportion of non-English speaking consumers, as determined by the Agency, information in the appropriate languages regarding the importance of the notice or a telephone number or address where consumers may contact the system to obtain a translated copy of the notice or assistance in the appropriate language.

C)        If directed by the Agency, a non-CWS supplier with significant deficiencies that have been corrected must inform its customers of the significant deficiencies, how the deficiencies were corrected, and the dates of correction under subsection (a)(7)(B).

b)         Compliance Monitoring

1)         Existing Groundwater Sources.  A GWS supplier that is not required by Section 611.802(a)(1) to meet the source water monitoring requirements of this Subpart S for any groundwater source must notify the Agency in writing that it provides at least 4-log treatment of viruses (using inactivation, removal, or an Agency-approved combination of 4-log virus inactivation and removal) before or at the first customer for the specified groundwater source and begin compliance monitoring in accordance with subsection (b)(3).  Notification to the Agency must include engineering, operational, or other information that the Agency requests to evaluate the submission.  If the supplier subsequently discontinues 4-log treatment of viruses (using inactivation, removal, or an Agency-approved combination of 4-log virus inactivation and removal) before or at the first customer for a groundwater source, the supplier must conduct groundwater source monitoring, as required under Section 611.802.

2)         New Groundwater Sources.  A GWS supplier that places a groundwater source in service which is not required by Section 611.802(a)(1) to meet the source water monitoring requirements of this Subpart S must comply with the requirements of subsections (b)(2)(A), (b)(2)(B), and (b)(2)(C).

A)        The supplier must notify the Agency in writing that it provides at least 4-log treatment of viruses (using inactivation, removal, or an Agency-approved combination of 4-log virus inactivation and removal) before or at the first customer for the groundwater source.  Notification to the Agency must include engineering, operational, or other information that the Agency requests by a SEP to evaluate the submission.

B)        The supplier must conduct compliance monitoring, as required under Section 611.803(b)(3), within 30 days after placing the source in service.

C)        The supplier must conduct groundwater source monitoring under Section 611.802 if it subsequently discontinues 4-log treatment of viruses (using inactivation, removal, or an Agency-approved combination of 4-log virus inactivation and removal) before or at the first customer for the groundwater source.

3)         Monitoring Requirements.  A GWS supplier subject to the requirements of subsection (a), (b)(1), or (b)(2) must monitor the effectiveness and reliability of treatment for that groundwater source before or at the first customer as follows:

A)        Chemical Disinfection

i)          GWS Suppliers Serving More Than 3,300 People.  A GWS supplier that serves more than 3,300 people must continuously monitor the residual disinfectant concentration using analytical methods specified in Section 611.531(b) at a location approved by the Agency and must record the lowest residual disinfectant concentration each day that water from the groundwater source is served to the public.  The GWS supplier must maintain the Agency-approved residual disinfectant concentration every day it serves water from the groundwater source to the public.  If there is a failure in the continuous monitoring equipment, the GWS supplier must conduct grab sampling every four hours until the continuous monitoring equipment is returned to service.  The supplier must resume continuous residual disinfectant monitoring within 14 days.

ii)         GWS Suppliers Serving 3,300 or Fewer People.  A GWS supplier that serves 3,300 or fewer people must monitor the residual disinfectant concentration using analytical methods specified in Section 611.531(b) at a location approved by the Agency and record the residual disinfection concentration each day that water from the groundwater source is served to the public.  The GWS supplier must determine and maintain the Agency-approved residual disinfectant concentration every day that it serves water from the groundwater source to the public.  The GWS supplier must take a daily grab sample during the hour of peak flow or at another time specified by the Agency.  If any daily grab sample measurement falls below the Agency-approved residual disinfectant concentration, the GWS supplier must take follow-up samples every four hours until the residual disinfectant concentration is restored to the Agency-approved level.  Alternatively, a GWS supplier that serves 3,300 or fewer people may monitor continuously and meet the requirements of subsection (b)(3)(A)(i).

B)        Membrane Filtration.  A GWS supplier that uses membrane filtration to meet the requirements of this Subpart S must monitor the membrane filtration process in accordance with all Agency-specified monitoring requirements and must operate the membrane filtration in accordance with all Agency-specified compliance requirements.  A GWS supplier that uses membrane filtration is in compliance with the requirement to achieve at least 4-log removal of viruses when it fulfills the following conditions:

i)          The membrane has an absolute molecular weight cut-off, or an alternative parameter that describes the exclusion characteristics of the membrane, that can reliably achieve at least 4-log removal of viruses;

ii)         The membrane process is operated in accordance with Agency-specified compliance requirements; and

iii)        The integrity of the membrane is intact.

C)        Alternative Treatment.  A GWS supplier that uses an Agency-approved alternative treatment to meet the requirements of this Subpart S by providing at least 4-log treatment of viruses (using inactivation, removal, or an Agency-approved combination of 4-log virus inactivation and removal) before or at the first customer must do both of the following:

i)          It must monitor the alternative treatment in accordance with all Agency-specified monitoring requirements; and

ii)         It must operate the alternative treatment in accordance with all operational requirements determined by the supplier that the Agency has approved as necessary to achieve at least 4-log treatment of viruses.

c)         Discontinuing Treatment.  A GWS supplier may discontinue 4-log treatment of viruses (using inactivation, removal, or an Agency-approved combination of 4-log virus inactivation and removal) before or at the first customer for a groundwater source if the supplier determines and documents and the Agency approves in writing that 4-log treatment of viruses is no longer necessary for that groundwater source. A system that discontinues 4-log treatment of viruses is subject to the source water monitoring and analytical methods requirements of Section 611.802 of this Subpart S.

d)         A failure to meet the monitoring requirements of subsection (b) is a monitoring violation and requires the GWS supplier to provide public notification under Section 611.904.

BOARD NOTE:  Derived from 40 CFR 141.403.

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