Current through August 26, 2024
(1) APPLICABILITY.
(a) The requirements of this subchapter
constitute the primary drinking water regulations for lead and copper. Unless
otherwise indicated, each of the provisions of this subchapter applies to
community water systems and non-transient, non-community water
systems.
(2) SCOPE. These
regulations establish a treatment technique that includes requirements for
corrosion control treatment, source water treatment, lead service line
replacement and public education. These requirements are triggered, in some
cases, by lead and copper action levels measured in samples collected at
consumers' taps.
(3) LEAD AND
COPPER ACTION LEVELS.
(a) The lead action
level is exceeded if the concentration of lead in more than 10% of tap water
samples collected during any monitoring period conducted in accordance with s.
NR 809.547 is greater than 0.015 mg/L, which means if the
"90th percentile" lead level is greater than 0.015 mg/L.
(b) The copper action level is exceeded if
the concentration of copper in more than 10% of tap water samples collected
during any monitoring period conducted in accordance with s.
NR 809.547 is greater than 1.3 mg/L, which means if the
"90th percentile" copper level is greater than 1.3 mg/L.
(c) The 90th percentile lead and copper
levels shall be computed as follows:
1. The
results of all lead or copper samples taken during a monitoring period shall be
placed in ascending order from the sample with the lowest concentration to the
sample with the highest concentration. Each sampling result shall be assigned a
number, ascending by single integers beginning with the number 1 for the sample
with the lowest contaminant level. The number assigned to the sample with the
highest contaminant level shall be equal to the total number of samples
taken.
2. The number of samples
taken during the monitoring period shall be multiplied by 0.9.
3. The contaminant concentration in the
numbered sample yielded by the calculation in subd. 2. is the 90th percentile
contaminant level.
4. For water
public water systems serving fewer than 100 people that are sampled at a rate
of 5 samples per monitoring period, the 90th percentile is computed by taking
the average of the highest and second highest concentrations.
5. For a public water system that has been
allowed by the department to be sampled at a rate of fewer than five samples in
accordance with federal rule
40 CFR
141.86(c), the sample result
with the highest concentration is considered the 90th percentile
value.
(4)
CORROSION CONTROL TREATMENT REQUIREMENTS.
(a)
All water suppliers shall install and operate optimal corrosion control
treatment as defined in s.
NR 809.04.
(b) Any public water system that complies
with the applicable corrosion control treatment requirements specified by the
department under ss.
NR 809.542 and 809.543 shall be deemed in compliance with
the treatment requirement contained in par. (a).
(5) SOURCE WATER TREATMENT REQUIREMENTS. Any
water supplier for a public water system exceeding the lead or copper action
level shall implement all applicable source water treatment requirements
specified by the department under s.
NR 809.544.
(6) LEAD SERVICE LINE REPLACEMENT
REQUIREMENTS. Any water supplier for a public water system exceeding the lead
action level after implementation of applicable corrosion control and source
water treatment requirements shall complete the lead service line replacement
requirements contained in s.
NR 809.545.
(7) PUBLIC EDUCATION REQUIREMENTS. Any water
supplier for a public water system exceeding the lead action level shall
implement the public education requirements contained in s.
NR 809.546. Any water supplier for a public water system
exceeding the copper action level shall annually provide public education on
the health effects of copper using language in Appendix B to subch. VII, and
information on reducing exposure to copper in drinking water similar to s.
NR 809.546.
