| (II) the executive director may decrease the quarterly
monitoring requirement specified in subsection (c)(2)(D)(iii)(I) of
this section provided that the executive director has determined that
the system is reliably and consistently below the MCL. In no case
shall the executive director make this determination unless a groundwater
system takes a minimum of two quarterly samples and a surface water
system takes a minimum of four quarterly samples;
(III) if the executive director determines that the
system is reliably and consistently below the MCL, the executive director
may allow the system to monitor annually. Systems that monitor annually
must monitor during the quarter that previously yielded the highest
(IV) systems which have three consecutive annual samples
with no detection of a contaminant may be granted a waiver as specified
in subparagraph (E) of this paragraph; and
(V) groundwater systems that have detected one or more
of the following two-carbon organic compounds: trichloroethylene,
tetrachloroethylene, 1,2-dichloroethane, 1,1,1-trichloroethane, cis-1,2-dichloroethylene,
trans-1,2-dichloroethylene, or 1,1-dichloroethylene shall monitor
quarterly for vinyl chloride. A vinyl chloride sample shall be taken
at each entry point to the distribution system at which one or more
of the two-carbon organic compounds was detected. If the result of
the first analysis does not detect vinyl chloride, the executive director
may reduce the quarterly monitoring frequency for vinyl chloride to
one sample during each compliance period. Surface water systems are
required to monitor for vinyl chloride as specified by the executive
(iv) The executive director may increase the required
VOC monitoring frequency, where necessary, to detect variations within
the system (e.g., fluctuations in concentration due to seasonal use,
changes in water source, etc.).
(E) Waivers for VOC monitoring. The executive director
may grant a waiver after evaluating the previous use (including transport,
storage, or disposal) of the contaminant within the watershed or zone
of influence of the water sources. If a determination by the executive
director reveals no previous use of the contaminant within the watershed
or zone of influence, a waiver may be granted. If previous use of
the contaminant is unknown or it has been used previously, then the
following factors shall be used to determine whether a waiver is granted:
(i) previous analytical results;
(ii) the proximity of the system to a potential point
or non-point source of contamination. Point sources include spills
and leaks of chemicals at or near a water treatment facility or at
drinking water sources manufacturing, distribution, or storage facilities,
or from hazardous and municipal waste landfills and other waste handling
or treatment facilities;
(iii) the environmental persistence and transport of
(iv) the number of persons served by the public water
system and the proximity of a smaller system to a larger system;
(v) how well the water source is protected against
contamination (e.g., is it a surface or groundwater system). Groundwater
systems must consider factors such as depth of the well, the type
of soil, and well construction. Surface water systems must consider
(vi) as a condition of the waiver, a groundwater system
must take one sample at each entry point to the distribution system
during the time the waiver is effective (i.e., one sample during two
compliance periods or six years) and update its vulnerability assessment
considering the factors listed in this paragraph. Based on this updated
vulnerability assessment, the executive director must reconfirm that
the system is not vulnerable. If the executive director does not make
this reconfirmation within three years of the initial determination,
then the waiver is invalid and the system is required to sample annually;
(vii) community and nontransient surface water systems
that do not detect a VOC contaminant listed in subsection (b)(2) of
this section may be considered by the executive director for a waiver
from the annual sampling requirements of subparagraph (C)(ii) of this
paragraph after completing the initial monitoring. Systems meeting
this criteria must be determined by the executive director to be non-vulnerable
based on a vulnerability assessment during each compliance period.
Each system receiving a waiver shall sample at the frequency specified
by the executive director (if any).
(F) Compositing for VOC monitoring. The executive director
may reduce the total number of samples a system must analyze by allowing
the use of compositing. Composite samples from a maximum of entry
points to the distribution system are allowed. Compositing of samples
must be done in the laboratory and analyzed within 14 days of sample
(i) If the VOC concentration in the composite sample
is 0.0005 mg/L or greater for any contaminant listed in subsection
(b)(2) of this section, then a follow-up sample must be taken and
analyzed within 14 days from each entry point to the distribution
system included in the composite.
(ii) If duplicates of the original sample taken from
each entry point to the distribution system used in the composite
are available, the system may use these instead of resampling. The
duplicate must be analyzed within 14 days of collection.
(iii) Compositing may only be permitted by the executive
director at entry points to the distribution system within a single
(iv) Procedures for compositing VOC samples are as
stated in 40 Code of Federal Regulations (CFR) §141.24(f)(14)(iv).
(d) Analytical requirements for organic contaminants.
Analytical procedures shall be performed in accordance with §290.119
of this title (relating to Analytical Procedures). Testing for organic
contaminants shall be performed at a laboratory certified by the executive
(e) Reporting requirements for organic contaminants.
The owner or operator of a public water system shall ensure 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 Water Supply
Division, MC 155, Texas Commission on Environmental Quality, P.O.
Box 13087, Austin, Texas 78711-3087.
(f) Compliance determination for organic contaminants.
Compliance with the MCLs of subsection (b)(1) and (2) of this section
shall be determined based on the analytical results obtained at each
entry point to the distribution system.
(1) If one sampling point is in violation of any MCL
in subsection (b) of this section, then the system is in violation
of the MCL for that contaminant.
(A) For systems monitoring more than once per year,
compliance with the MCL is determined by a running annual average
at each sampling point.
(B) Systems monitoring annually or less frequently
whose sample result exceeds the MCL must begin quarterly sampling;
systems will not be considered in violation of the MCL until they
have completed one year of quarterly sampling.
(C) If any sample result will cause the running annual
average to exceed the MCL at any sampling point, the system is out
of compliance with the MCL immediately.
(D) If a system fails to collect the required number
of samples, compliance will be based on the total number of samples
(E) If a sample result is less than the detection limit,
zero will be used to calculate the annual average.
(2) The executive director has the authority to determine
compliance or initiate enforcement action based upon analytical results
and other information compiled by sanctioned representatives and agencies.
(3) 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 notification requirements for organic contaminants.
A public water system that violates the requirements of this section
must notify the executive director and the system's customers. If
a public water system has a distribution system separate from other
parts of the distribution system with no interconnections, the executive
director may allow the system to give public notice to only that portion
of the system that is out of compliance.
(1) A system that violates an MCL given in subsection
(b) of this section, shall report to the executive director and notify
the public as provided under §290.122(b) of this title (relating
to Public Notification).
(2) 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.
(h) Best available technology for organic contaminants.
Best available technology for treatment of violations of MCLs in subsection
(b) of this section are listed in 40 CFR §141.61. Copies are
available for review in the Water Supply Division, MC 155, Texas Commission
on Environmental Quality, P.O. Box 13087, Austin, Texas 78711-3087.
|Source Note: The provisions of this §290.107 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