(ii) a waterborne disease outbreak, as defined in 40
Code of Federal Regulations §141.2, or other waterborne emergencies
for situations that do not meet this definition, but that still have
the potential to have serious adverse effects on health as a result
of short-term exposure. These could include outbreaks not related
to treatment deficiencies, as well as situations that have the potential
to cause outbreaks, such as failures or significant interruption in
water treatment processes, natural disasters that disrupt the water
supply or distribution system, chemical spills, or unexpected loading
of possible pathogens into the source water; or
(iii) the public water system has failed to maintain
adequate disinfectant residuals as described in subsection (d) of
this section and as described in §290.110 of this title.
(B) The executive director will provide written notification
to the public water system in the event a public water system is required
to institute special precautions, protective measures, or issue boil
water notices to customers at the discretion of the executive director.
Upon written notification from the executive director, the public
water system shall implement special precautions, protective measures,
or issue boil water notices to customers within 24 hours or within
the time period specified by the executive director.
(C) The public water system shall provide any required
information to the executive director to document that the public
water system has met the requirements for special precautions, protective
measures, and boil water notices required at the discretion of the
executive director under this paragraph.
(6) Required actions prior to rescinding a boil water
notice. A public water system shall notify customers throughout the
distribution system or in the affected area(s) of the distribution
system that a boil water notice has been rescinded after the public
water system has met the requirements of this paragraph. A boil water
notice issued under the requirements of this subsection shall remain
in effect until the public water system has provided required compliance
documentation to the executive director which establishes that the
public water system has met the following requirements, as applicable:
(A) water distribution system pressures in excess of
20 psi are consistently being maintained throughout the distribution
system in accordance with the flowchart found in §290.47(e) of
this title;
(B) affected area(s) of the distribution system have
been thoroughly flushed until a minimum of 0.2 mg/L free chlorine
residual or 0.5 mg/L chloramine residual (measured as total chlorine)
is present and is consistently being maintained in each finished water
storage tank and throughout the distribution system as described in
subsection (d) of this section;
(C) finished water entering the distribution system,
produced by a treatment plant that is treating surface water or groundwater
under the direct influence of surface water, has a turbidity level
that is consistently being maintained below 1.0 NTU;
(D) actions required by the executive director under
paragraph (5) of this subsection have been met and the public water
system is operating in accordance with §290.111(h)(2) of this
title as described in paragraph (5)(A)(i) of this subsection; and
(E) water samples for microbiological analysis, marked
as "special" on the laboratory sample submission form, were collected
from representative locations throughout the distribution system or
in the affected area(s) of the distribution system after the public
water system has met all other applicable requirements of this paragraph
and the water samples collected for microbiological analysis are found
negative for coliform organisms. The water samples described in this
subparagraph shall be analyzed at laboratories in accordance with §290.119
of this title (relating to Analytical Procedures).
(F) A public water system shall notify customers throughout
the distribution system or in the affected area(s) of the distribution
system that a boil water notice has been rescinded within 24 hours
or no later than the next business day, using the language and format
specified in Figure: 30 TAC §290.47(c)(3) of this title, once
the public water system has met the requirements of this paragraph.
The public water system shall provide a copy of the "Boil Water Notice
Rescinded" notice and a copy of the associated microbiological laboratory
analysis results, as required by subparagraph (E) of this paragraph,
to the executive director within ten days after the public water system
has issued the rescind notice to customers in accordance with §290.122(f)
of this title.
(r) Minimum pressures. All public water systems shall
be operated to provide a minimum pressure of 35 psi throughout the
distribution system under normal operating conditions. The system
shall also be operated to maintain a minimum pressure of 20 psi during
emergencies such as fire fighting. As soon as safe and practicable
following the occurrence of a natural disaster, a public water system
that is an affected utility shall maintain a minimum of 35 psi throughout
the distribution system during an extended power outage.
(s) Testing equipment. Accurate testing equipment or
some other means of monitoring the effectiveness of any chemical treatment
or pathogen inactivation or removal processes must be used by the
system.
(1) Flow-measuring devices and rate-of-flow controllers
that are required by §290.42(b) and (d) of this title (relating
to Water Treatment) shall be calibrated at least once every 12 months.
Well meters required by §290.41(c)(3)(N) of this title shall
be calibrated at least once every three years.
(2) Laboratory equipment used for compliance testing
shall be properly calibrated.
(A) pH meters shall be properly calibrated.
(i) Benchtop pH meters shall be calibrated according
to manufacturer specifications at least once each day.
(ii) The calibration of benchtop pH meters shall be
checked with at least one buffer each time a series of samples is
run, and if necessary, recalibrated according to manufacturer specifications.
(iii) On-line pH meters shall be calibrated according
to manufacturer specifications at least once every 30 days.
(iv) The calibration of on-line pH meters shall be
checked at least once each week with a primary standard or by comparing
the results from the on-line unit with the results from a properly
calibrated benchtop unit. If necessary, the on-line unit shall be
recalibrated with primary standards.
(B) Turbidimeters shall be properly calibrated.
(i) Benchtop turbidimeters shall be calibrated with
primary standards at least once every 90 days. Each time the turbidimeter
is calibrated with primary standards, the secondary standards shall
be restandardized.
(ii) The calibration of benchtop turbidimeters shall
be checked with secondary standards each time a series of samples
is tested, and if necessary, recalibrated with primary standards.
(iii) On-line turbidimeters shall be calibrated with
primary standards at least once every 90 days.
(iv) The calibration of on-line turbidimeters shall
be checked at least once each week with a primary standard, a secondary
standard, or the manufacturer's proprietary calibration confirmation
device or by comparing the results from the on-line unit with the
results from a properly calibrated benchtop unit. If necessary, the
on-line unit shall be recalibrated with primary standards.
(C) Chemical disinfectant residual analyzers shall
be properly calibrated.
(i) The accuracy of manual disinfectant residual analyzers
shall be verified at least once every 90 days using chlorine solutions
of known concentrations.
(ii) The accuracy of continuous disinfectant residual
analyzers shall be checked at least once every seven days with a chlorine
solution of known concentration or by comparing the results from the
on-line analyzer with the result of approved benchtop method in accordance
with §290.119 of this title.
(iii) If a disinfectant residual analyzer produces
a result which is not within 15% of the expected value, the cause
of the discrepancy must be determined and corrected and, if necessary,
the instrument must be recalibrated.
(D) Analyzers used to determine the effectiveness of
chloramination in §290.110(c)(5) of this title shall be properly
verified in accordance with the manufacturer's recommendations every
90 days. These analyzers include monochloramine, ammonia, nitrite,
and nitrate equipment used by the public water system.
(E) Ultraviolet (UV) light disinfection analyzers shall
be properly calibrated.
(i) The accuracy of duty UV sensors shall be verified
with a reference UV sensor monthly, according to the UV sensor manufacturer.
(ii) The reference UV sensor shall be calibrated by
the UV sensor manufacturer on a yearly basis, or sooner if needed.
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