Current through September 18, 2024
Authority: IC 13-13-5; IC 13-14-8-7; IC 13-14-9; IC 13-18-3;
IC 13-18-16
Affected: IC 13-18
Sec. 41.
(a) Each
system shall complete the corrosion control treatment requirements described in
this section that are applicable to such system under section 40 of this rule.
Based upon the results of lead and copper tap monitoring and water quality
parameter monitoring, small and medium size water systems exceeding the lead or
copper action level shall recommend installation of one (1) or more of the
corrosion control treatments listed in subsection (c)(1) that the system
believes constitutes optimal corrosion control for that system. The
commissioner may require the system to conduct additional water quality
parameter monitoring in accordance with section 38(c) of this rule to assist
the commissioner in reviewing the system's recommendation.
(b) The commissioner may require any small or
medium size system that exceeds the lead or copper action level to perform
corrosion control studies under subsection (c) to identify optimal corrosion
control treatment for the system.
(c) Requirements for the performance of
corrosion control studies shall be as follows:
(1) Any public water system performing
corrosion control studies shall evaluate the effectiveness of each of the
following treatments, and, if appropriate, combinations of the following
treatments to identify the optimal corrosion control treatment for that system:
(A) Alkalinity and pH adjustment.
(B) Calcium hardness adjustment.
(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.
(2) The water system shall evaluate each of
the corrosion control treatments using either pipe rig/loop tests, metal coupon
tests, partial-system tests, or analyses based on analogous treatments with
other systems of similar size, water chemistry, and distribution system
configuration.
(3) The water system
shall measure the following water quality parameters in any tests conducted
under subdivision (2) before and after evaluating the corrosion control
treatments listed in subdivision (1):
(A)
Lead.
(B) Copper.
(C) pH.
(D) Alkalinity.
(E) Calcium.
(F) Conductivity.
(G) Orthophosphate (when an inhibitor
containing a phosphate compound is used).
(H) Silicate (when an inhibitor containing a
silicate compound is used).
(I)
Water temperature.
(4)
The water system shall identify all chemical or physical constraints that limit
or prohibit the use of a particular corrosion control treatment and document
such constraints with at least one (1) of the following:
(A) Data and documentation showing that a
particular corrosion control treatment has adversely affected other water
treatment processes when used by another water system with comparable water
quality and characteristics.
(B)
Data and documentation demonstrating that a water system has previously
attempted to evaluate a particular corrosion control treatment and has found
the treatment is ineffective or adversely affects other water quality treatment
processes, or both.
(5)
The water system shall evaluate the effect of the chemicals used for corrosion
control treatment on other water quality treatment processes.
(6) On the basis of an analysis of the data
generated during each evaluation, the water system shall recommend to the
commissioner in writing the treatment option that the corrosion control studies
indicate constitutes optimal corrosion control treatment for that system. The
water system shall provide a rationale for its recommendation along with all
supporting documentation specified in subdivisions (1) through (5).
(d) Requirements for the
designation of optimal corrosion control treatment shall be as follows:
(1) Based upon consideration of available
information including, where applicable, studies performed under subsection (c)
and a system's recommended treatment alternative, the commissioner shall either
approve the corrosion control treatment option recommended by the system or
designate alternative corrosion control treatments from among those listed in
subsection (c)(1). When designating optimal treatment, the commissioner shall
consider the effects that additional corrosion control treatment will have on
water quality parameters and on other water quality treatment
processes.
(2) The commissioner
shall notify the system of its decision on optimal corrosion control treatment
in writing and explain the basis for this determination. If the commissioner
requests additional information to aid the review, the water system shall
provide the information.
(e) Each system shall properly install and
operate throughout its distribution system the optimal corrosion control
treatment designated by the commissioner under subsection (d).
(f) The commissioner shall evaluate the
results of all lead and copper tap samples and water quality parameter samples
submitted by the water system and determine whether the system has properly
installed and operated the optimal corrosion control treatment designated by
the commissioner in subsection (d). Upon reviewing the results of tap water and
water quality parameter monitoring by the system, both before and after the
system installs optimal corrosion control treatment, the commissioner shall
designate the following:
(1) A minimum value
or 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 seven
(7.0) unless the commissioner determines that meeting a pH level of seven (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 commissioner 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.
(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 in this subsection shall be those the commissioner determines
to reflect optimal corrosion control treatment for the system. The commissioner
may designate values for additional water quality control parameters determined
by the commissioner to reflect optimal corrosion control for the system. The
commissioner shall notify the system in writing of these determinations and
explain the basis for the decisions.
(g) All systems optimizing corrosion control
shall continue to operate and maintain optimal corrosion control treatment,
including maintaining water quality parameter values at or above minimum values
or within ranges designated by the commissioner under subsection (f) in all
samples collected under section 38(d) through 38(f) of this rule. Compliance
with the requirements shall be determined every six (6) months, as specified in
section 38(d) of this rule. A water system is out of compliance with the
requirements for a six (6) month period if it has excursions for any
commissioner-specified parameter for more than nine (9) days during the period.
An excursion occurs whenever the daily value for one (1) or more of the water
quality parameters measured at a sampling location is below the minimum value
or outside the range designated by the commissioner. The commissioner may
delete results of obvious sampling errors from this calculation. Daily values
are calculated as follows:
(1) On days when
more than one (1) 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.
(2) On days when only one (1) measurement for
the water quality parameter is collected at the sampling location, the daily
value shall be the results of that measurement.
(3) 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.
(h) Upon its own initiative or in response to
a request by a water system or other interested party, the commissioner may
modify its determination of the optimal corrosion control treatment under
subsection (d) or optimal water quality control parameters under subsection
(f). A request for modification by a system or other interested party shall be
in writing, explain why the modification is appropriate, and provide supporting
documentation. The commissioner may modify the determination where the
commissioner concludes that such change is necessary to ensure that the system
continues to optimize corrosion control treatment. A revised determination
shall be made in writing, set forth the new treatment requirements, explain the
basis for the commissioner's decision, and provide an implementation schedule
for completing the treatment modifications.
