Current through September 17, 2024
006.01 General
26-006.01A The provisions of this section
apply to community water systems using only ground water (except ground water
under the direct influence of surface water, as defined in 179 NAC
3-002) and serving 1,000 or fewer
people.
26-006.01B Following any
total coliform-positive sample taken under the provisions of this section,
systems must comply with the repeat monitoring requirements and E. coli
analytical requirements in
26-009.
26-006.01C Once all monitoring required by
this section and
26-009 for a calendar month has been
completed, systems must determine whether any coliform treatment technique
triggers specified in
26-010 have been exceeded. If any
trigger has been exceeded, systems must complete assessments as required by
26-010.
006.02 Monitoring Frequency for Total
Coliforms
The monitoring frequency for total coliforms is one sample
per month, except as provided for under 26-006.03 through 26-006.06.
006.03 Transition to 179 NAC 26
26-006.03A All systems must continue to
monitor according to the total coliform monitoring schedules under 179 NAC
3-004 that were in effect on March 31,
2016, unless any of the conditions in 26-006.05 are triggered on or after April
1, 2016, or unless otherwise directed by the Department.
26-006.03B Beginning April 1, 2016, the
Department must perform a special monitoring evaluation during each sanitary
survey to review the status of the system, including the distribution system,
to determine whether the system is on an appropriate monitoring schedule. After
the Department has performed the special monitoring evaluation during each
sanitary survey, the Department may modify the system's monitoring schedule, as
necessary, or it may allow the system to stay on its existing monitoring
schedule, consistent with the provisions of the section. The Department will
not allow systems to begin less frequent monitoring under the special
monitoring evaluation unless the system has already met the applicable criteria
for less frequent monitoring in this section.
006.04 Criteria for Reduced Monitoring
The Department may reduce the monitoring frequency from
monthly monitoring to no less than quarterly monitoring if the system is in
compliance with Title 179 NAC 10 and demonstrates that it meets the criteria in
items 1 through 3 below. A system that loses its licensed operator must return
to monthly monitoring the month following that loss.
1. The system has a clean compliance history
for a minimum of 12 months.
2. The
most recent sanitary survey shows the system is free of sanitary defects (or
has an approved plan and schedule to correct them and is in compliance with the
plan and the schedule), has a protected water source and meets approved
construction standards.
3. The
system meets at least one of the following criteria:
a. An annual site visit by the Department
that is equivalent to a Level 2 assessment or an annual Level 2 assessment by a
party approved by the Department and correction of all identified sanitary
defects (or an approved plan and schedule to correct them and is in compliance
with the plan and schedule).
b.
Cross connection control, as approved by the Department.
c. Continuous disinfection entering the
distribution system and a residual in the distribution system in accordance
with criteria specified by the Department.
d. Demonstration of maintenance of at least a
4-log removal or inactivation of viruses as provided for under 179 NAC
8-006.02C.
e. Other equivalent enhancements to the water
system barriers as approved by the Department.
006.05 Return to Routine Monthly Monitoring
Requirements
Systems on quarterly monitoring that experience any of the
events in items 1 through 4 below must begin monthly monitoring the month
following the event. The system must continue monthly monitoring until it meets
the reduced monitoring requirements in 26-006.04.
1. The system triggers a Level 2 assessment
or two Level 1 assessments in a rolling 12-month period.
2. The system has an E. coli
MCL violation.
3. The
system has a coliform treatment technique violation.
4. The system has two 179 NAC 26 monitoring
violations in a rolling 12-month period.
006.06 Additional Routine Monitoring the
Month Following a Total Coliform-Positive Sample
Systems collecting samples on a quarterly frequency must
conduct additional routine monitoring the month following one or more total
coliform-positive samples (with or without a Level 1 treatment technique
trigger). Systems must collect at least three routine samples during the next
month, except that the Department may waive this requirement if the conditions
of
26-006.06A,
26-006.06B, or
26-006.06C are
met. Systems may either collect samples at regular time intervals throughout
the month or may collect all required routine samples on a single day if
samples are taken from different sites. Systems must use the results of
additional routine samples in coliform treatment technique trigger
calculations.
26-006.06A The
Department may waive the requirement to collect three routine samples the next
month in which the system provides water to the public if the Department, or an
individual approved by the Department, performs a site visit before the end of
the next month in which the system provides water to the public. Although a
sanitary survey need not be performed, the site visit must be sufficiently
detailed to allow the Department to determine whether additional monitoring
and/or any corrective action is needed. The Department cannot approve an
employee of the system to perform this site visit, even if the employee is an
individual approved by the Department to perform sanitary surveys.
26-006.06B The Department may waive the
requirement to collect three routine samples the next month in which the system
provides water to the public if the Department has determined why the sample
was total coliform-positive and has established that the system has corrected
the problem or will correct the problem before the end of the next month in
which the system serves water to the public. In this case, the Department must
document this decision to waive the following month's additional monitoring
requirement in writing, have it approved and signed by the supervisor of the
Department official who recommends such a decision, and make this document
available to the EPA and the public. The written documentation must describe
the specific cause of the total coliform-positive sample and what action the
system has taken and/or will take to correct this problem.
26-006.06C The Department may not waive the
requirement to collect three additional routine samples the next month in which
the system provides water to the public solely on the grounds that all repeat
samples are total coliform-negative. If the Department determines that the
system has corrected the contamination problem before the system takes the set
of repeat samples required in
26-009, and all repeat samples were
total coliform-negative, the Department may waive the requirement for
additional routine monitoring the next month.
