| (ii) After the initiation of quarterly sampling, the
executive director may return a system to the routine annual nitrate
monitoring frequency if quarterly sampling shows that the system is
reliably and consistently below the nitrate MCL for a minimum of four
consecutive quarters.
(7) Nitrite monitoring frequency. All public water
systems shall monitor for nitrite at the following frequency.
(A) All public water systems shall routinely take one
nitrite sample during each nine-year compliance cycle. All public
water systems shall monitor at the time designated by the executive
director during each compliance period during each nine-year compliance
cycle. New entry points will be scheduled for nitrite sample collection
during the first year of operation, and then every nine years thereafter
unless increased nitrite monitoring is required in accordance with
this paragraph.
(B) The executive director may reduce the monitoring
frequency for nitrite by granting a waiver to the routine monitoring
frequency.
(i) To be considered for a waiver, a system shall demonstrate
that the nitrite concentration in the initial sample was less than
50% of the nitrite MCL.
(ii) If the executive director grants a waiver, it
shall be made in writing and shall set forth the basis for the determination.
The determination may be initiated by the executive director. The
executive director shall review and, where appropriate, revise the
waiver of monitoring frequency when other data relevant to the system
becomes available.
(iii) A system that receives a waiver to the routine
nitrite monitoring frequency must sample at a frequency specified
by the executive director.
(C) The executive director may increase the monitoring
frequency for nitrite.
(i) A system shall sample quarterly for at least one
year following any sample in which the nitrite concentration is greater
than or equal to 50% of the MCL.
(ii) The executive director may allow a system to return
to the routine monitoring frequency after determining the system is
reliably and consistently less than the MCL.
(8) Confirmation sampling for all IOCs. The executive
director may require a public water system to confirm the results
of any individual sample.
(A) If a sample result exceeds the MCL, a public water
system may be required to collect one additional sample to confirm
the results of the initial test. If an additional sample is required:
(i) Confirmation samples must be collected at the same
entry point to the distribution system as the sample that exceeded
the MCL;
(ii) Confirmation samples for IOCs except nitrate and
nitrite shall be collected as soon as possible after the system receives
the analytical results of the first sample; and
(iii) Confirmation samples for nitrate and nitrite
shall be collected within 24 hours of the system's receipt of notification
of the analytical results of the first sample. Systems unable to comply
with the 24-hour sampling requirement must immediately notify the
consumers served by the public water system in accordance with subsection
(f) of this section. Systems exercising this option must take and
analyze a confirmation sample within two weeks of notification of
the analytical results of the first sample.
(B) The executive director may require a confirmation
sample for any sample with questionable results.
(9) More frequent monitoring. The executive director
may require more frequent monitoring than specified in paragraphs
(4) - (7) of this subsection.
(d) Analytical requirements for IOCs. Analytical procedures
shall be performed in accordance with §290.119 of this title
(relating to Analytical Procedures). Testing for inorganic contaminants
shall be performed at a laboratory certified by the executive director.
(e) Reporting requirements for IOCs. The owner or operator
of a public water system shall ensure that the executive director
is provided with a copy of the results of any test, measurement, or
analysis required by this subsection. The copies must be submitted
within the first ten days following the month in which the result
is received by the public water system, or the first ten days following
the end of the required monitoring period as provided by this subsection,
whichever occurs first. The copies must be mailed to the Texas Commission
on Environmental Quality, Water Supply Division, MC 155, P.O. Box
13087, Austin, Texas 78711-3087.
(f) Compliance determination for IOCs. Compliance with
this section shall be determined using the following criteria.
(1) Compliance with the MCL for each IOC shall be based
on the analytical results obtained at each individual sampling point.
(2) A public water system that exceeds the levels for
nitrate, nitrite, or the sum of nitrate and nitrite specified in subsection
(b) of this section commits an acute MCL violation. Compliance shall
be based on the results of the single sample. If a confirmation sample
is collected, compliance shall be based on the average result of the
original and confirmation samples.
(3) A public water system that exceeds the levels of
antimony, arsenic, asbestos, barium, beryllium, cadmium, chromium,
cyanide, fluoride, mercury, selenium, or thallium (i.e., any IOC except
nitrate and nitrite) specified in subsection (b) of this section at
any sampling point commits an MCL violation.
(A) For systems that are sampling annually or less
frequently, compliance may be based on the results of a single sample,
if a confirmation sample is not collected.
(B) For systems that are sampling annually or less
frequently, if a confirmation sample is collected, compliance will
be based on the average result of the original and confirmation samples.
(C) For systems that are sampling more frequently than
annually, compliance is based on the running annual average for each
sampling point.
(D) If a single quarterly sample would cause the running
annual average to be exceeded, then the system is immediately out
of compliance.
(4) Any result below the method detection limits of
40 CFR §141.23(a)(4)(i) shall be considered to be zero for the
purpose of calculating compliance.
(5) The executive director may exclude the results
of obvious sampling errors from the compliance calculations.
(6) Compliance with the IOC MCLs must be based on the
results of all samples required by the executive director, regardless
of whether that number is greater or less than the minimum required
number.
(7) For purposes of determining compliance, arsenic
results must be reported to the nearest 0.001 milligram per liter.
(8) A public water system that fails to do a required
public notice or certify that the public notice has been performed
commits a public notice violation.
(g) Public notice for IOCs. A public water system that
violates the requirements of this section must notify the executive
director and the system's customers.
(1) A public water system that violates the MCL for
nitrate, nitrite, or the sum of nitrate and nitrite shall notify the
executive director within 24 hours and the water system customers
of this acute violation in accordance with the requirements of §290.122(a)
of this title (relating to Public Notification).
(2) A public water system that violates the MCL for
nitrate, nitrite, or the sum of nitrate and nitrite that is unable
to comply with the 24-hour confirmation sampling requirement must
immediately notify the consumers served by the public water system
in accordance with §290.122(a) of this title.
(3) A public water system that fails to meet the MCL
for any of the regulated IOCs except nitrate and nitrite (i.e., antimony,
arsenic, asbestos, barium, beryllium, cadmium, chromium, cyanide,
fluoride, mercury, selenium, and thallium) shall notify the executive
director by the end of the next business day and the water system
customers in accordance with the requirements of §290.122(b)
of this title.
(4) A public water system that fails to conduct the
monitoring required by this section must notify its customers of the
violation in accordance with the requirements of §290.122(c)
of this title.
(5) If a public water system has a distribution system
separable from other parts of the distribution system with no interconnections,
the executive director may allow the system to give public notice
to only the area served by that portion of the system that is out
of compliance.
(h) Best available technology (BAT) for IOCs. BAT for
treatment of violations of MCLs in subsection (b) of this section
are listed in 40 CFR §141.62.
(i) Small system compliance technologies (SSCTs) for
arsenic. SSCTs for arsenic are listed in 40 CFR §141.62(d) and
may be utilized with commission approval. When point-of-use or point-of-entry
devices are used for compliance, the water system must develop a program
for the long-term operation, maintenance, and monitoring of the devices
to ensure adequate performance.
(j) Bottled water. In accordance with 40 CFR §141.101,
bottled water may be used on a temporary basis only and with approval
by the commission in order to avoid unreasonable risk to health.
|
| Source Note: The provisions of this §290.106 adopted to be effective September 13, 2000, 25 TexReg 8880; amended to be effective May 16, 2002, 27 TexReg 4127; amended to be effective February 19, 2004, 29 TexReg 1373; amended to be effective December 23, 2004, 29 TexReg 11729; amended to be effective January 9, 2008, 33 TexReg 198; amended to be effective March 30, 2017, 42 TexReg 1466 |
