Current through August 26, 2024
Each water supplier shall complete the following corrosion
control treatment requirements which are applicable to their public water
system under s.
NR 809.542.
(1)
WATER SUPPLIER RECOMMENDATION REGARDING CORROSION CONTROL TREATMENT. Based upon
the results of lead and copper tap monitoring and water quality parameter
monitoring, water supplier for a small and medium-size water systems exceeding
the lead or copper action level shall recommend installation of one or more of
the corrosion control treatments listed in sub. (3) (a) which the water
supplier believes constitutes optimal corrosion control for that public water
system. The department may require the water supplier to conduct additional
water quality parameter monitoring in accordance with s.
NR 809.548(2) to assist the department
in reviewing the water supplier's recommendation. In no case may the time
period for installation of optimal corrosion control treatment on a small or
medium-size system exceed the schedule as listed in s.
NR 809.542(5) (a) to (h).
(2) DEPARTMENT DECISION TO REQUIRE STUDIES OF
CORROSION CONTROL TREATMENT BY SMALL AND MEDIUM-SIZE SYSTEMS. The department
may require the water supplier of any small or medium-size system that exceeds
the lead or copper action level to perform corrosion control studies under sub.
(3) to identify optimal corrosion control treatment for the public water
system.
(3) PERFORMANCE OF
CORROSION CONTROL STUDIES.
(a) Any water
supplier 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 public water system:
1. Alkalinity and
pH adjustment.
2. Calcium hardness
adjustment.
3. 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.
(b) The water
supplier shall evaluate each of the corrosion control treatments listed in par.
(a) using either pipe rig or loop tests, metal coupon tests, partial-system
tests, or analyses based on documented analogous treatments with other public
water systems of similar size, water chemistry and distribution system
configuration.
(c) The water
supplier shall measure all of the following water quality parameters in any
tests conducted before and after evaluating the corrosion control treatments
listed in par. (a):
1. Lead.
2. Copper.
3. pH.
4. Alkalinity.
5. Calcium.
6. Conductivity.
7. Orthophosphate (when an inhibitor
containing a phosphate compound is used).
8. Silicate when an inhibitor containing a
silicate compound is used.
9. Water
temperature.
(d) The
water supplier 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 of the following:
1. Data and documentation showing that a
particular corrosion control treatment has adversely affected other water
treatment processes when used by another public water system with comparable
water quality characteristics.
2.
Data and documentation demonstrating that the water supplier has previously
attempted to evaluate a particular corrosion control treatment and has found
that the treatment is ineffective or adversely affects other water quality
treatment processes, or both.
(e) The water supplier shall evaluate the
effect of the chemicals used for corrosion control treatment on other water
quality treatment processes.
(f) On
the basis of an analysis of the data generated during each evaluation, the
water supplier shall recommend to the department in writing the treatment
option that the corrosion control studies indicate constitutes optimal
corrosion control treatment for that public water system. The water supplier
shall provide a rationale for its recommendation along with all supporting
documentation specified in pars. (a) to (e).
(4) DEPARTMENT EVALUATION OF OPTIMAL
CORROSION CONTROL TREATMENT.
(a) Based upon
consideration of available information including, where applicable, studies
performed under sub. (3) and a water supplier's recommended treatment
alternative, the department shall either approve the corrosion control
treatment option recommended by the water supplier, or designate alternative
corrosion control treatments from among those listed in sub. (3) (a). When
approving optimal treatment, the department shall consider the effects that
additional corrosion control treatment will have on water quality parameters
and on other water quality treatment processes.
(b) The department shall notify the water
supplier of its decision on optimal corrosion control treatment in writing and
explain the basis for this determination. If the department requests additional
information to aid its review, the water supplier shall provide the
information.
(5)
INSTALLATION OF OPTIMAL CORROSION CONTROL. Each water supplier shall properly
install and operate throughout the public water system's distribution system
the optimal corrosion control treatment approved by the department under sub.
(4).
(6) DEPARTMENT REVIEW OF
TREATMENT. The department shall evaluate the results of all lead and copper tap
samples and water quality parameter samples submitted by the water supplier and
determine whether the water supplier has properly installed and operated the
optimal corrosion control treatment approved by the department in sub. (4).
Upon reviewing the results of tap water and water quality parameter monitoring
by the water supplier, both before and after the water supplier installs
optimal corrosion control treatment, the department shall establish ranges for
water quality parameters.
(7)
APPROVAL OF OPTIMAL WATER QUALITY CONTROL PARAMETERS. The department shall
review the water supplier's recommendations and select the values for the
applicable water quality control parameters listed in sub. (3) which reflect
optimal corrosion control treatment for the public water system. The department
may specify values for additional water quality control parameters to reflect
optimal corrosion control for the public water system. The department shall
notify the water supplier in writing of these determinations and explain the
basis for its decision. At a minimum, the department shall establish all of the
following:
(a) A minimum value or a range of
values for pH measured at each entry point to the distribution
system.
(b) A minimum pH value,
measured in all tap samples. The value shall be equal to or greater than 7.0,
unless the water supplier provides information to indicate that meeting a pH
level of 7.0 is not technologically feasible or is not necessary for the public
water system to optimize corrosion control.
(c) 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
department determines is necessary to protect the interior walls of the pipes
of the distribution system from corrosion.
(d) 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.
(e)
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.
(8)
CONTINUED OPERATION AND MONITORING. All water suppliers 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 department under sub. (7), in
accordance with this subsection for all samples collected under s.
NR 809.548(4). Compliance with the
requirements of this subsection shall be determined every 6 months, as
specified under s.
NR 809.548(4). A public water system is
out of compliance with the requirements of this subsection for a 6-month period
if it has excursions for any department-specified parameter on more than 9 days
during the 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 department. The department
may delete results of obvious sampling errors from this calculation. Daily
values are calculated as follows:
(a) 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. If EPA has
approved an alternative formula under
40 CFR
142.16 in the department's application for a
program revision submitted pursuant to
40 CFR
142.12, the department's formula shall be
used to aggregate multiple measurements taken at a sampling point for the water
quality parameter in lieu of the formula in this paragraph.
(b) 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.
(c) 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.
(9) MODIFICATION OF DEPARTMENT TREATMENT
DECISIONS. Upon its own initiative or in response to a request by a water
supplier or other interested party, the department may modify its determination
of the optimal corrosion control treatment under sub. (4) or optimal water
quality control parameters under sub. (6). A request for modification by a
water supplier or other interested party shall be in writing, explain why the
modification is appropriate, and provide supporting documentation. The
department may modify its determination if it concludes that a change is
necessary to ensure that the water supplier 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 department's
decision, and provide an implementation schedule for completing the treatment
modifications.
(10) TREATMENT
DECISIONS BY EPA IN LIEU OF THE DEPARTMENT. The EPA regional administrator may
review treatment determinations made by the department under sub. (4), (6) or
(8) and issue federal treatment determinations consistent with the requirements
of those subsections if the regional administrator finds any of the following:
(a) The department has failed to issue a
treatment determination by the applicable deadlines contained in s.
NR 809.542.
(b) The department has abused its discretion
in a substantial number of cases or in cases affecting a substantial
population.
(c) The technical
aspects of the department's determination would be indefensible in an expected
federal enforcement action taken against a water supplier.
