Current through Register No. 13, March 27, 2025
(a) The owner of a public water system
subject to the requirements of
Env-Ws
380.23 and which serves at least 10,000 people shall
comply with the requirements in this section and
Env-Ws
380.26.
(b) The system owner shall determine:
(1) The TTHM annual average using the
procedure specified in (c) below; and
(2) The HAA5 annual average using the
procedure specified in (d) below.
(c) The TTHM annual average shall be
calculated during the same period as the HAA5 annual average and be based on
the following:
(1) A system owner collecting
data under the provisions of 40 CFR 141 Subpart M, July 1, 2000 edition shall
use the results of the samples collected during the last 4 quarters of required
monitoring;
(2) A system owner
using HAA5 occurrence data that meet the provisions of (d)(2) below, shall use
TTHM data collected at the same time under the requirements of Env-Ws 317.70
and Env-Ws
327.70; and
(3) A system owner using HAA5 occurrence data
that meet the provisions of (e)(1) or (2) below, shall use TTHM data collected
at the same time under the provisions of Env-Ws 317.70 and
Env-Ws
327.70.
(d) The HAA5 annual average shall be:
(1) The annual average during the same period
as the TTHM annual average; and
(2)
Based on the following:
a. A system owner
collecting data under the provisions of 40 CFR 141 Subpart M, July 1, 2000
edition, shall use the results of the samples collected during the last 4
quarters of required monitoring; and
b. A system owner collecting 4 quarters of
HAA5 occurrence data that meets the routine monitoring sample number and
location requirements for TTHM set forth in Env-Ws 317.70 and
Env-Ws
327.70, and the handling and analytical method
requirements of Env-Ws 382.06, shall use those
data to determine whether the requirements of this section apply.
(e) A system owner who
fails to collect the HAA5 data specified in (d) above shall:
(1) Conduct monitoring for HAA5 that meets
the routine monitoring sample number and location requirements for TTHM set
forth in Env-Ws 317.70 and
Env-Ws
327.70 and the handling and analytical method
requirements of Env-Ws 382.06 to determine the
HAA5 annual average and whether the requirements of (l) below apply;
or
(2) Comply with all other
provisions of this section as if the HAA5 monitoring had been conducted and the
results required compliance with (l) below.
(f) If the department determines that the
data set determined under (c) or (d) above is not representative, the
department shall require that a system owner use a more representative annual
data set for the purpose of determining applicability of the requirements of
this section. The determination that a more representative data set is needed
shall be based on the following criteria.
(1)
Water quality reported to the department pursuant to administrative rules
Env-Ws 380 shall be reviewed to determine a divergence in treated water quality
during the period represented by the data set from the norm.
(2) The location of the sampling points in
the data set shall be reviewed to determine whether the points are uniformly
distributed throughout the water delivery system.
(g) The department shall approve the data set
offered in place of the data set determined under (c) or (d) above if it
determines that the data set is more representative of actual system
performance and is equivalent to the data set collected under the criteria
specified in (c) or (d) above.
(h)
A system owner shall submit the following data to the department:
(1) A system owner collecting TTHM and HAA5
data under the provisions of 40 CFR 141 Subpart M, July 1, 2000 edition, as
required by (c)(1) and (d)(1) above, shall submit the results of the samples
collected during the last 12 months of required monitoring;
(2) A system owner collecting 4 consecutive
quarters of HAA5 occurrence data that meet the routine monitoring sample number
and location for TTHM in Env-Ws 317.70 and
Env-Ws
327.70 and the handling and analytical method
requirements of Env-Ws 382.06 as allowed by
(c)(2) and (d)(1) above, shall submit that data; and
(3) A system owner conducting monitoring for
HAA5 using the monitoring requirements specified by (c)(3) and (e)(1) above
shall submit TTHM and HAA5 data.
(i) A system owner electing to comply with
all other provisions of this section as if the HAA5 monitoring had been
conducted and the results required compliance with this section, as allowed
under (e)(2) above, shall notify the department in writing of the
election.
(j) Until the department
has approved the data identified in (i) above, the system owner shall conduct
monitoring for HAA5 using the monitoring requirements specified under (d)
above.
(k) A system having either a
TTHM annual average greater than or equal to 0.064 mg/L or an HAA5 annual
average greater than or equal to 0.048 mg/L during the same monitoring period
specified in (c) above shall conduct disinfection profiling as follows:
(1) A system owner shall develop a
disinfection profile of its disinfection practice for a period of up to 3
years;
(2) A system owner shall
monitor daily for a period of 12 consecutive calendar months to determine the
total logs of inactivation, expressed as log inactivation, for each day of
operation, based on the CT99.9 values specified in Tables 380-2 through 380-9
as appropriate, through the entire treatment plant;
(3) A system owner shall conduct the
monitoring required in (2), above as follows:
a. A system with a single point of
disinfectant application prior to entrance to the distribution system shall
conduct the monitoring in (4) a. through d. below; and
b. A system with more than one point of
disinfectant application shall conduct the monitoring in paragraphs (4) a.
through d. below for each disinfection segment;
(4) A system owner shall monitor the
parameters necessary to determine the total inactivation ratio, using
analytical methods described in
Env-Ws
380.13, as follows:
a. The temperature of the disinfected water
shall be measured at least once per day at each residual disinfectant
concentration sampling point during peak hourly flow;
b. If the system uses chlorine, the pH of the
disinfected water shall be measured at least once per day at each chlorine
residual disinfectant concentration sampling point during peak hourly
flow;
c. The disinfectant contact
time(s) (T) shall be determined for each day during peak hourly flow;
and
d. The residual disinfectant
concentration(s) (C) of the water before or at the first customer and prior to
each additional point of disinfection shall be measured each day during peak
hourly flow.
(l) A system owner may submit a written
request to the department to use existing operational data in lieu of the
monitoring conducted under the provisions of (k)(2) above.
(m) The written request shall include the
following:
(1) The water system
name;
(2) The water system EPA
number;
(3) The most recent
operational data for the past 3 years; and
(4) A profile generated using the operational
data specified in (3) above.
(n) The data offered pursuant to (l) above
shall be representative of giardia lamblia inactivation through the entire
treatment plant and not just of certain treatment segments.
(o) The department shall accept the data
offered under (l), above, if the operational data is substantially equivalent
to data collected under the provisions of (k)(2).
(p) Until the department approves the request
submitted pursuant to (l) above, the system owner shall conduct monitoring
under the provisions of (k)(2), above.
(q) In addition to the monitoring conducted
under the provisions of (k)(2) above, to develop the disinfection profile, the
system owner may elect to meet the following:
(1) In addition to the disinfection profile
generated under (k)(2) above, the owner of a public water system that has
existing operational data may use the data to develop a disinfection profile
for additional years;
(2) A system
owner may use the additional yearly disinfection profiles to develop a
benchmark under the provisions of
Env-Ws
380.26; and
(3) The data shall be representative of
inactivation through the entire treatment plant and not just of certain
treatment segments.
(r)
A system owner shall calculate the total inactivation ratio as follows:
(1) If a system uses only one point of
disinfectant application, the system owner shall determine the total
inactivation ratio for the disinfection segment by:
a. Determining one CTcalc/CT99.9
(inactivation ratio) before or at the first customer during peak hourly flow;
or
b. Determining successive
sequential inactivation ratios, between the point of disinfectant application
and a point before or at the first customer during peak hourly flow;
(2) Under b. above, a system owner
shall calculate the [SIGMA] CTcalc/CT99.9 (total inactivation ratio) by
determining the inactivation ratios for each sequence and then adding the
inactivation ratio values together to determine the total inactivation
ratio;
(3) If a system uses more
than one point of disinfectant application before the first customer, the
system owner shall determine the CT value of each disinfection segment
immediately prior to the next point of disinfectant application, or for the
final segment, before or at the first customer, during peak hourly flow and the
inactivation ratio value of each segment and the total inactivation ratio shall
be calculated using the method in (1) and (2) above; and
(4) The system owner shall determine the
total logs of inactivation by multiplying the value calculated in (1) or (3)
above by 3.0.
(s) The
owner of a system that uses either chloramines or ozone for primary
disinfection shall calculate the logs of inactivation for viruses based on
methods accepted by the department. Methods accepted by the department shall be
based on tables for log inactivation based on published, peer-reviewed and
reproducible research.
(t) The
system owner shall retain disinfection profile data in the form of a graph or
as a spreadsheet and have the data available when the department conducts a
sanitary survey pursuant to Env-Ws 306.
#5098, eff 3-18-91, EXPIRED 3-18-97
New. #6521, eff 6-4-97 (See
Revision Note at chapter heading for Env-Ws 300); ss by #8352, eff 5-14-05
(formerly part of Env-Ws 380.28
)