Current through Register Vol. 48, No. 12, March 22, 2024
a) Corrosion Control Required. A supplier
must complete the applicable corrosion control treatment under Section
611.1352 on or before the
deadlines in this Section.
1) Large Systems.
Each large system supplier (one regularly serving more than 50,000 persons)
must complete the corrosion control treatment steps subsection (d) specifies,
unless subsection (b)(2) or (b)(3) deems the supplier to have optimized
corrosion control.
2) Small and
Medium-Sized Systems. Each small system supplier (one regularly serving 3,300
or fewer persons) and each medium-sized water system (one regularly serving
3,301 to 50,000 persons) must complete the corrosion control treatment steps
subsection (e) specifies, unless subsection (b)(1), (b)(2), or (b)(3) deems the
supplier to have optimized corrosion control.
b) Suppliers Deemed to Have Optimized
Corrosion Control. Subsection (b)(1), (b)(2), or (b)(3) deems a supplier to
have optimized corrosion control treatment if the supplier satisfies the
criterion the subsection specifies, freeing the supplier from the obligation to
complete the applicable corrosion control treatment steps in this Section. Any
system subsection (b)(1), (b)(2), or (b)(3) deems to have optimized corrosion
control having treatment in place must continue operating and maintaining
optimal corrosion control treatment and meeting any requirements the Agency
determines are appropriate to ensure that the supplier maintains optimal
corrosion control treatment.
1) Small and
Medium-Sized Systems Meeting Action Levels. Meeting the lead and copper action
levels during each of two consecutive six-month monitoring periods under
Section 611.1356 deems a small or
medium-sized system supplier to have optimized corrosion control.
2) SEP for Activities Equivalent to Corrosion
Control. The Agency must issue a SEP deeming a supplier to have optimized
corrosion control treatment upon determining that the supplier conducts
activities equivalent to the corrosion control steps under this Section. In
making this determination, the Agency must specify the water quality control
parameters representing optimal corrosion control under Section
611.1352(f). A
water supplier the Agency deems as having optimized corrosion control under
this subsection (b)(2) must operate in compliance with the Agency-designated
optimal water quality control parameters under Section
611.1352(g) and
must continue to conduct lead and copper tap and water quality parameter
sampling under Sections
611.1356(d)(3)
and 611.1357(d). A
supplier must provide the Agency with the following information to support the
Agency issuing a SEP under this subsection (b)(2):
A) The results of all test samples the
supplier collected for each of the water quality parameters in Section
611.1352(c)(3);
B) A report explaining the test methods the
supplier used to evaluate the corrosion control treatments in Section
611.1352(c)(1),
the results of all tests conducted, and the basis for the supplier selecting
the optimal corrosion control treatment;
C) A report explaining how the supplier
installed corrosion control and how the supplier maintains the corrosion
control to insure minimal lead and copper concentrations at consumers' taps;
and
D) The results of tap water
samples the supplier collected under Section
611.1356 at least once every six
months for one year after the supplier installed corrosion control.
3) Results Less Than Practical
Quantitation Level (PQL) for Lead. Monitoring results deem supplier to have
optimized corrosion control if the supplier submits results of tap water
monitoring under Section
611.1356 and source water
monitoring under Section
611.1358 demonstrating that for
two consecutive six-month monitoring periods the difference between the 90th
percentile tap water lead level, computed under Section
611.1350(c)(3),
and the highest source water lead concentration is less than the PQL that
Section 611.1359(a)(2)(A)
specifies.
A) Having a highest source water
lead level below the MDL deems a supplier to have optimized corrosion control
under this subsection (b)(3) if the 90th percentile tap water lead level is
less than or equal to the lead PQL for two consecutive six-month monitoring
periods.
B) Any supplier this
subsection (b)(3) deems to have optimized corrosion control must continue tap
water monitoring for lead and copper no less frequently than once every three
calendar years using the reduced number of sites Section
611.1356(c)
specifies and collecting the samples at times and locations Section
611.1356(d)(4)(D)
specifies.
C) Any supplier this subsection (b)(3) deems
to have optimized corrosion control must notify the Agency in writing under
Section 611.1360(a)(3)
of any upcoming long-term change in treatment or the addition of a new source,
as that Section describes. The Agency must review and approve the addition of a
new source or any long-term change in water treatment before the supplier adds
the source or implements the long-term change.
D) A supplier is not deemed to have optimized
corrosion control under this subsection (b)(3) and must implement corrosion
control treatment under subsection (b)(3)(E), unless the supplier meets the
copper action level.
E) Any
supplier this subsection (b)(3) no longer deems to have optimized corrosion
control must implement corrosion control treatment under subsection (e). Any
large system supplier this subsection (b)(3) no longer deems to have optimized
corrosion control must adhere to the schedule that subsection (e) specifies for
a medium-sized water system supplier, with the time periods for completing each
step being triggered by the date the supplier is no longer deemed to have
optimized corrosion control under this subsection (b)(3).
c) Suppliers Not Required to
Complete Corrosion Control Steps for Having Met Both Action Levels
1) Any small or medium-sized water system
supplier, otherwise required to complete the corrosion control steps because it
exceeded the lead or copper action level, may cease completing the treatment
steps after fulfilling specific conditions:
A)
The supplier meets both the copper and lead action levels during each of two
consecutive six-month monitoring periods under Section 611.1356; and
B) The supplier submits the results for those
two consecutive six-month monitoring periods to the Agency.
2) A supplier that ceases
completing the corrosion control steps under subsection (c)(1) (or the Agency,
if appropriate) must resume completion of the applicable treatment steps,
beginning with the first treatment step that the supplier previously did not
complete in its entirety, if the supplier thereafter exceeds the lead or copper
action level during any monitoring period.
3) The Agency may issue a SEP requiring a
supplier to repeat treatment steps the supplier previously completed if the
Agency determines that this is necessary to properly implement the treatment
requirements of this Section. The Agency must explain the basis for its
decision in any SEP.
4) A small or
medium-sized water system supplier exceeding the lead or copper action level
triggers the requirement to implement corrosion control treatment steps under
subsection (e) (including systems deemed to have optimized corrosion control
under subsection (b)(1)).
d) Treatment Steps for Large Systems. Except
as subsections (b)(2) and (b)(3) provide otherwise, a large system must
complete certain corrosion control treatment steps as specific rules provide).
1) Step 1: Initial monitoring during two
consecutive six-month monitoring periods (under Sections
611.1356(d)(1)
and 611.1357(b)).
2) Step 2: Corrosion control studies (under
Section 611.1352(c)).
3) Step 3: The Agency approving optimal
corrosion control treatment in a SEP (under Section
611.1352(d)).
4) Step 4: Installing optimal corrosion
control treatment (under Section
611.1352(e)).
5) Step 5: Completing follow-up sampling
(under Sections 611.1356(d)(2)
and 611.1357(c)).
6) Step 6: The Agency reviewing installed
treatment and approving optimal water quality control parameters (under Section
611.1352(f)).
7) Step 7: Complying with the
Agency-specified optimal water quality control parameters (under Section
611.1352(g))
and continuing tap sampling (under Sections
611.1356(d)(3)
and 611.1357(d)).
e) Treatment Steps and Deadlines
for Small and Medium-Sized Water Systems. Except as subsection (b) provides
otherwise, a small and medium-sized system supplier must complete certain
corrosion control treatment steps as specific rules provide before the
indicated time periods.
1) Step 1: The
supplier must conduct initial tap sampling (under Sections
611.1356(d)(1)
and 611.1357(b))
until the supplier either exceeds the lead or copper action level or becomes
eligible for reduced monitoring under Section
611.1356(d)(4).
A supplier exceeding the lead or copper action level must recommend optimal
corrosion control treatment (under Section
611.1352(a))
within six months after the end of the monitoring period during which the
exceedance occurred.
2) Step 2:
Within 12 months after the end of the monitoring period during which a supplier
exceeds the lead or copper action level, the Agency may require the supplier to
perform corrosion control studies (under Section
611.1352(b)).
If the Agency does not require the supplier to perform corrosion control
studies, the Agency must issue a SEP specifying optimal corrosion control
treatment (under Section
611.1352(d))
within the appropriate of specific timeframes:
A) For a medium-sized water system, within 18
months after the end of the monitoring period during which the supplier
exceeded the lead or copper action level; or
B) For a small system, within 24 months after
the end of the monitoring period during which the supplier exceeded the lead or
copper action level.
3)
Step 3: If the Agency requires a supplier to perform corrosion control studies
under step 2 (subsection (e)(2)), the supplier must complete the studies (under
Section 611.1352(c))
within 18 months after the Agency requires the supplier to conduct the
studies.
4) Step 4: If a supplier
performs corrosion control studies under step 2 (subsection (e)(2)), the Agency
must issue a SEP approving optimal corrosion control treatment (under Section
611.1352(d))
within six months after the supplier completes step 3 (under subsection
(e)(3)).
5) Step 5: The supplier
must install optimal corrosion control treatment (under Section
611.1352(e))
within 24 months after the Agency approves that treatment.
6) Step 6: The supplier must complete
follow-up sampling (under Sections
611.1356(d)(2)
and 611.1357(c))
within 36 months after the Agency approves optimal corrosion control
treatment.
7) Step 7: The Agency
must review the supplier's installation of treatment and issue a SEP approving
optimal water quality control parameters (under Section
611.1352(f))
within six months after the supplier completes step 6 (under subsection
(e)(6)).
8) Step 8: The supplier
must comply with the Agency-approved optimal water quality control parameters
(under Section 611.1352(g))
and continue tap sampling (under Sections
611.1356(d)(3)
and 611.1357(d)).
BOARD NOTE: This Section corresponds with Section
611.1351 and derives from
40 CFR
141.81
(2020).