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Title: Section 5-1.41 - Corrosion Control Treatment Steps and Requirements

Effective Date

01/17/2018

5-1.41 Corrosion Control Treatment Steps and Requirements.

(a) Each system shall complete the applicable corrosion control treatment requirements found in subdivision (c) of this section unless it is deemed to have optimized corrosion control as provided under subdivision (b) of this section.

(b) Optimized corrosion control. A system is deemed to have optimized corrosion control and is not required to complete the applicable corrosion control treatment steps identified in this section if the water system satisfies the criteria specified in one of the paragraphs (1) through (3) of this subdivision. Any such system deemed to have optimized corrosion control under this subdivision, and which has treatment in place, shall continue to operate and maintain optimal corrosion control treatment and meet any requirements that the State determines appropriate to ensure optimal corrosion control treatment is maintained.

(1) Any water system that serves 50,000 or fewer people is considered to have optimal corrosion control treatment if the water system meets the lead and copper action levels during each of two consecutive six-month monitoring periods conducted in accordance with section 5-1.42.  

(2) Any water system may be deemed by the State to have optimized corrosion control treatment if the system demonstrates to the satisfaction of the State that it has conducted activities equivalent to applicable corrosion control steps. Water systems deemed to have optimized corrosion control under this paragraph shall operate in compliance with State-designated optimal water quality parameters and continue to conduct lead and copper tap and water quality parameter sampling in accordance with sections 5-1.42(b)(3) and 5-1.43(b)(3). A system shall provide information to the State to support a determination under this subdivision which includes, but is not limited to:

(i) the results of all samples collected for each of the water quality parameters in section 5-1.43; 

(ii) a report explaining the test methods used by the water system to evaluate the corrosion control treatments listed in subdivision (c)(3)(ii) of this section, the results of all tests conducted, and the basis for the system's selection of optimal corrosion control treatment;

(iii) a report explaining how corrosion control has been installed and how it is being maintained to insure minimal lead and copper concentrations at consumers' taps; and

(iv) the results of first draw lead and copper tap water samples collected in accordance with section 5-1.42 for two consecutive six-month monitoring periods after corrosion control has been installed.  

(3) A water system is deemed to have optimized corrosion control if it meets the copper action level and can demonstrate:

(i) the difference between the results of the 90th percentile tap water lead level and the highest source water lead level is less than 0.005 mg/L for two consecutive six-month monitoring periods. The 90th percentile tap water lead level shall be sampled in accordance with section 5-1.42 and source water lead level shall be sampled in accordance with section 5-1.44; and

(ii) a system’s highest source water lead level is below the Method Detection Limit, and the 90th percentile tap water lead level is less than or equal to 0.005 mg/L for two consecutive 6-month monitoring periods.

(4) Any water system deemed to have optimized corrosion control in accordance with this section shall continue monitoring for lead and copper in tap water no less frequently than once every three calendar years using the reduced number of sites specified in section 5-1.42(a)(3) and collecting the samples at times and locations specified in section 5-1.42(c), unless it meets the requirements for a nine year waiver as specified in section 5-1.42(f).

(5) Any system triggered into corrosion control because it is no longer deemed to have optimized corrosion control under this section shall implement corrosion control treatment in accordance with the deadlines in subdivision (c)(2) of this section. Any such system serving more than 50,000 persons shall adhere to the schedule specified in subdivision (c)(2) of this section for systems serving 50,000 or fewer persons, with the time periods for completing each step being triggered by the date the system is no longer deemed to have optimized corrosion control under this section.  

(6) Any water system deemed to have optimized corrosion control shall notify the State in writing, pursuant of section 5-1.48(i), of any upcoming long-term change in treatment or addition of a new source. The water system shall obtain approval from the State before implementing the addition of a new source or long-term change in water treatment. The State may require any such system to conduct additional monitoring or to take other action the State deems appropriate to ensure that such systems maintain minimal levels of corrosion in the distribution system.

(c) Corrosion control treatment steps and deadlines.

(1) A system serving more than 50,000 persons shall complete the following corrosion control treatment steps, unless it is deemed to have optimized corrosion control as provided in subdivisions (b)(2) and (b)(3) of this section:  

(i) Step 1: The water system shall conduct initial first draw lead and copper tap sampling and water quality parameter sampling in accordance with sections 5-1.42 and 5-1.43. If the lead or copper action level exceeds the 90th percentile, the water system shall conduct source water sampling in accordance with section 5-1.44 within a schedule specified by the State.

(ii) Step 2: The water system shall complete corrosion control studies as specified by the State within 18 months after the end of the monitoring period during which the system exceeds one of the action levels. 

(iii) Step 3: The water system shall install optimal corrosion control treatment within 24 months after the State designates such treatment.

(iv) Step 4: After installation of optimal corrosion control treatment, the water system shall complete first draw lead and copper tap sampling and water quality parameter follow-up sampling in accordance with sections 5-1.42(b)(2) and 5-1.43(b)(2) during the two consecutive six-month monitoring periods immediately following installation of treatment.

(v) Step 5: After State designation of water quality parameters for optimal corrosion control treatment, the water system shall operate in compliance with State-designated optimal water quality parameter values in accordance with subdivision (g) of this section; and continue to conduct first draw lead and copper tap sampling and water quality parameter sampling in accordance with sections 5-1.42(b)(3) and 5-1.43(b)(3).  

(2) Systems serving 50,000 or fewer persons. Except as provided in subdivision (b) of this section, a system that serves 50,000 or fewer persons shall complete the following corrosion control treatment steps:  

(i) Step 1: The water system shall conduct initial first draw lead and copper tap sampling in accordance with section 5-1.42 within a schedule specified by the State. If the lead or copper action level is exceeded at the 90th percentile the water system shall conduct water quality parameter sampling and source water sampling in accordance with sections 5-1.43 and 5-1.44. 

(ii) Step 2: The water system shall recommend optimal corrosion control treatment within six months after the end of the monitoring period during which the system exceeds one of the action levels. Within 12 months after the end of the monitoring period during which a system exceeds the lead or copper action level, the State may designate optimal corrosion control treatment or require the system to perform corrosion control studies. If the State requires corrosion control studies to be conducted, the water system shall complete corrosion control studies as specified in subdivision (c)(3) of this section. 

(a) Systems serving populations greater than 3,300 but less than 50,000 shall perform such studies within 18 months after the end of the monitoring period during which the system exceeds the lead or copper action level.

(b) Systems serving 3,300 or fewer persons shall perform such studies within 24 months after the end of the monitoring period during which the system exceeds the lead or copper action  level.

(iii) Step 3: The water system shall install optimal corrosion control treatment within 24 months after the State designates such treatment.

(iv) Step 4: After installation of optimal corrosion control treatment, the water system shall complete first draw lead and copper tap sampling and water quality parameter follow-up sampling in accordance with sections 5-1.42(b)(2) and 5-1.43(b)(2) during the two consecutive six-month monitoring periods immediately following installation of treatment.  

(v) Step 5: After State designation of water quality parameters for optimal corrosion control treatment, the water system shall operate in compliance with State-designated optimal water quality parameter values in accordance with subdivision (g) of this section; and continue to conduct first draw lead and copper tap sampling and water quality parameter sampling in accordance with sections 5-1.42(b)(3) and 5-1.43(b)(3).  

(3) Content of corrosion control studies. Corrosion control studies shall follow methods that include but are not limited to the following:  

(i) an evaluation of the effectiveness of each of the following treatments, and, if appropriate, combinations of the following treatments using standard engineering tests on other systems of similar size, water chemistry and distribution system configuration:

(a) alkalinity and pH adjustment;

(b) calcium hardness adjustment; and

(c) the addition of a phosphate or silicate based corrosion inhibitor at a concentration sufficient to maintain an effective residual concentration in all test tap samples;

(ii) measurements of appropriate water quality parameters to assess performance of corrosion control including: lead; copper; pH; alkalinity; calcium; conductivity; temperature; silica or orthophosphate;

(iii) an assessment of effectiveness of treatment including the potential for adverse effects on other water quality treatment processes; and  

(iv) identification of the optimal corrosion control treatment(s) for the system, including a rationale of the treatment steps for consideration by the State.

(4) Conditions for ceasing treatment steps. Any water system that serves 50,000 or fewer people. and that is required to complete the corrosion control steps due to its exceedance of the lead or copper action level, may cease completing the treatment steps whenever the water system meets both action levels during each of two consecutive six-month monitoring periods. The lead and copper results from both monitoring periods shall be submitted to the State for approval for ceasing treatment steps. If an action level is exceeded in a later monitoring period the water system shall complete the remaining applicable treatment steps.

(d) Designation of optimal corrosion control treatment. Based upon consideration of available information including, where applicable, corrosion control studies performed under subdivision (c) of this section and a system's proposed treatment alternative, the State will either:

(1) approve the corrosion control treatment option recommended by the system; or

(2) require alternative corrosion control treatment(s) as specified by the State. The State may also ask for additional information or modifications.

(e) Installation of optimal corrosion control. Each system shall properly install and operate throughout its distribution system the optimal corrosion control treatment(s) approved by the State under subdivision (d) of this section.

(f) State review of treatment and designation of optimal water quality control parameters. Based upon a review of the results of lead and copper tap water samples and water quality parameter samples submitted to the State by the water system from both before and after the installation of optimal corrosion control treatment, the State shall determine whether the system has properly installed and operated the optimal corrosion control treatment, and designate water quality parameter values, or a range of values, within which the system must operate. Such water parameters shall include:

(1) A minimum value or a range of values for pH measured at each entry point to the distribution system;

(2) A minimum pH value, measured in all tap samples. Such value shall be equal to or greater than 7.0, unless the State determines that meeting a pH level of 7.0 is not technologically feasible or is not necessary for the system to optimize corrosion control;

(3) If a corrosion inhibitor is used, a minimum concentration or a range of concentrations for the inhibitor, measured at each entry point to the distribution system and in all tap samples, that the State determines is necessary to form a passivating film on the interior walls of the pipes of the distribution system; 

(4) If alkalinity is adjusted as part of optimal corrosion control treatment, a minimum concentration or a range of concentrations for alkalinity, measured at each entry point to the distribution system and in all tap samples; and 

(5) If calcium carbonate stabilization is used as part of corrosion control, a minimum concentration or a range of concentrations for calcium, measured in all tap samples.

The values for the applicable water quality control parameters listed above shall be those that the State determines to reflect optimal corrosion control treatment for the system. The State may designate values for additional water quality control parameters determined by the State to reflect optimal corrosion control for the system. The State shall notify the system in writing of these determinations and explain the basis for its decisions.  

(g) Continued operation and maintenance.

(1) All systems optimizing corrosion control shall continue to operate and maintain optimal corrosion control treatment, including maintaining water quality parameters at or above minimum values or within ranges designated by the State under subdivision (f) of this section for all samples collected in accordance with section 5-1.43(b)(3) and section 5-1.43(c). Compliance with the requirements of this paragraph shall be determined every six months, as specified in section 5-1.42(b)(3).  A water system is out of compliance with the requirements of this paragraph if it has excursions for any State-designated parameter on more than nine (9) days during any six-month period. An excursion occurs whenever the daily value for one or more of the water quality parameters measured at a sampling location is below the minimum value or outside the range designated by the State. The State has the discretion to delete results of obvious sampling errors from this calculation.  Daily values are calculated as follows:

(i) On days when more than one measurement for the water quality parameter is collected at the sampling location, the daily value shall be the average of all results collected during the day regardless of whether they are collected through continuous monitoring, grab sampling, or a combination of both.  

(ii) On days when only one measurement for the water quality parameter is collected at the sampling location, the daily value shall be the result of that measurement.

(iii) On days when no measurement is collected for the water quality parameter at the sampling location, the daily value shall be the daily value calculated on the most recent day on which the water quality parameter was measured at the sample site.

(2) Modification of State treatment decisions. A water system may request a modification of its State designated optimal corrosion control treatment. The request shall be submitted in writing and include the reason for the modification along with supporting data.

Volume

VOLUME A (Title 10)

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