| (A) Source water. Public water systems must monitor
source water (including raw and treated purchased water) to establish
baseline ammonia, nitrite, and nitrate levels (all as nitrogen) at
least once to determine the availability of ammonia for chloramine
formation and to provide a reference for downstream nitrite and nitrate
levels that may indicate nitrification. If any source has more than
0.5 mg/L free ammonia (as nitrogen) in the initial sample, then raw
water ammonia (as nitrogen) shall be monitored monthly for six months
to determine the baseline free ammonia level.
(B) Water entering distribution system. All public
water systems that have chloramines present shall perform sampling
to represent the water entering the distribution system.
(i) Total chlorine, free ammonia (as nitrogen) and
monochloramine shall be monitored weekly at all entry points to the
distribution system or at a location before the first customer.
(ii) Nitrite and nitrate (as nitrogen) levels at the
first customer shall be monitored monthly for at least six months
to determine baseline nitrite and nitrate levels in the water prior
to consumption. Nitrite and nitrate samples collected at the first
customer will not be used for compliance with §290.106 of this
title (relating to Inorganic Contaminants).
(iii) Nitrite and nitrate (as nitrogen) shall be monitored
quarterly at the first customer after establishing the baseline. Nitrite
and nitrate samples collected at entry points for compliance with §290.106
of this title may be used for these quarterly samples.
(C) Treatment sampling. Public water systems that inject
chlorine at any location to form chloramines or to convert from chloramines
to free chlorine must monitor to ensure that chemical addition is
effective and the proper chlorine to ammonia (as nitrogen) ratio is
achieved. Samples must be collected and analyzed weekly and whenever
the chemical dosage is changed.
(i) Sampling must be performed upstream of the chlorine
or ammonia chemical injection point, whichever is furthest upstream.
(ii) Sampling must be performed downstream of all the
chlorine and ammonia chemical injection points.
(iii) The residual of the chemical injected upstream
must be determined to properly dose the downstream chemical where
sample taps are present or required under §290.42(e)(7)(C)(ii)
of this title (relating to Water Treatment).
(iv) The total chlorine, ammonia (as nitrogen), and
monochloramine residuals must all be monitored if the treatment occurs
before the entry point.
(v) The ammonia (as nitrogen) and monochloramine residuals
must all be monitored if the treatment occurs in the distribution
system. The monitoring must occur at the same time as a compliance
sampling required under paragraph (4)(E) of this subsection.
(D) Distribution system. Public water systems that
distribute water and have a chloramine residual must ensure the efficacy
of disinfection within the distribution system.
(i) Monochloramine and free ammonia (as nitrogen) must
be monitored weekly at the same time as a compliance sample required
under paragraph (4) of this subsection.
(ii) Nitrite and nitrate (as nitrogen) must be monitored
quarterly.
(d) Analytical requirements. All monitoring required
by paragraphs (1) and (2) of this subsection must be conducted at
a facility approved by the executive director and using methods that
conform to the requirements of §290.119 of this title (relating
to Analytical Procedures). All monitoring for chloramine effectiveness
required by paragraphs (3) - (6) of this subsection must be analyzed
to the accuracy provided therein.
(1) The free chlorine or chloramine residual (measured
as total chlorine) must be measured to a minimum accuracy of plus
or minus 0.1 mg/L. Color comparators may be used for distribution
system samples only. When used, a color comparator must have current
reagents, an unfaded and clear color comparator, a sample cell that
is not discolored or stained, and must be properly stored in a cool,
dark location where it is not subjected to conditions that would result
in staining. The color comparator must be used in the correct range.
If a sample reads at the top of the range, the sample must be diluted
with chlorine-free water, then a reading taken and the resulting residual
calculated.
(2) The chlorine dioxide residual must be measured
to a minimum accuracy of plus or minus 0.05 mg/L using a method that
conforms to the requirements of §290.119 of this title. The DPD-glycine
method using a colorimeter or spectrophotometer may be utilized only
with the written permission of the executive director.
(3) The free ammonia level must be measured to a minimum
accuracy of plus or minus 0.1 mg/L.
(4) The monochloramine level must be measured to a
minimum accuracy of plus or minus 0.15 mg/L using a procedure that
has the ability to distinguish between monochloramine and other forms
of chloramine.
(5) The nitrate (as nitrogen) level must be measured
to a minimum accuracy of plus or minus 0.1 mg/L.
(6) The nitrite (as nitrogen) level must be measured
to a minimum accuracy of plus or minus 0.01 mg/L.
(e) Reporting requirements. Any owner or operator of
a public water system subject to the provisions of this section is
required to report to the executive director the results of any test,
measurement, or analysis required by this section.
(1) Public water systems exceeding the MRDL for chlorine
dioxide in subsection (b)(3) of this section must report the exceedance
to the executive director within 24 hours of the event.
(2) Public water systems that use surface water sources
or groundwater sources under the direct influence of surface water
must submit a Surface Water Monthly Operating Report (commission Form
0102C), a Surface Water Monthly Operating Report (commission Form
0102D) for alternative technologies, or a Surface Water Monthly Operational
Report for Plants That Do Not Have a Turbidimeter on Each Filter (commission
Form 0103) each month.
(3) Public water systems that use chlorine dioxide
must submit a Chlorine Dioxide Monthly Operating Report (commission
Form 0690) each month.
(4) Public water systems that use purchased water or
groundwater sources only must complete a Disinfection Level Quarterly
Operating Report (commission Form 20067) each quarter.
(A) Community and nontransient, noncommunity public
water systems must submit the Disinfection Level Quarterly Operating
Report each quarter, by the tenth day of the month following the end
of the quarter.
(B) Transient, noncommunity public water systems must
retain the Disinfection Level Quarterly Operating Reports and must
provide a copy if requested by the executive director.
(5) Systems that use chloramines must retain their
NAP required under §290.46(z) of this title and must provide
a copy upon request by the executive director.
(6) Monthly and quarterly reports required by this
section must be submitted to the Water Supply Division, MC 155, Texas
Commission on Environmental Quality, P.O. Box 13087, Austin, Texas
78711-3087 by the tenth day of the month following the end of the
reporting period.
(f) Compliance determinations. Compliance with the
requirements of this section shall be determined using the following
criteria.
(1) All samples used for compliance must be obtained
at sampling sites designated in the monitoring plan.
(A) All samples collected at sites designated in the
monitoring plan as microbiological and disinfectant residual monitoring
sites shall be included in the compliance determination calculations.
(B) Samples collected at sites in the distribution
system not designated in the monitoring plan shall not be included
in the compliance determination calculations.
(2) A public water system that fails to conduct the
monitoring tests required by this section commits a monitoring violation.
(3) A public water system that fails to report the
results of the monitoring tests required by this section commits a
reporting violation.
(4) A public water system that uses surface water sources
or groundwater sources under the direct influence of surface water
and fails to meet the requirements of subsection (b)(2) of this section
for a period longer than four consecutive hours commits a nonacute
treatment technique violation. A public water system that fails to
conduct the additional testing required by subsection (c)(1)(B)(iii)
of this section also commits a nonacute treatment technique violation.
(5) A public water system that uses chlorine dioxide
and exceeds the level specified in subsection (b)(3) of this section
violates the MRDL for chlorine dioxide.
(A) If a public water system violates the MRDL for
chlorine dioxide and any of the three additional distribution samples
exceeds the MRDL, the system commits an acute MRDL violation for chlorine
dioxide.
Cont'd... |
