Washington Administrative Code
Title 246 - Health, Department of
WATER SYSTEMS
Chapter 246-290 - Group A public water supplies
Part 6 - SURFACE WATER TREATMENT
Subpart D - Requirements for Other Unfiltered Systems
Section 246-290-690 - Criteria to remain unfiltered
Universal Citation: WA Admin Code 246-290-690
Current through Register Vol. 24-18, September 15, 2024
(1) For a system not using the "limited alternative to filtration" option to remain unfiltered, the purveyor using a surface water or GWI source shall meet the source water quality and site-specific conditions under this section, as demonstrated through monitoring conducted in accordance with WAC 246-290-694.
(2) Source water quality conditions necessary to remain unfiltered.
(a) Coliform limits.
(i) The purveyor shall ensure that
representative source water samples taken before the first point of
disinfection have a fecal coliform density less than or equal to 20/100 ml in
ninety percent or more of all samples taken during the six previous calendar
months the system served water to the public. Samples collected on days when
source water turbidity exceeds 1.0 NTU shall be included when determining
compliance with this requirement.
(ii) The purveyor shall submit a written
report to the department if no source fecal coliform data has been submitted
for days when source turbidity exceeded 1.0 NTU. The report shall document why
sample results are not available and shall be submitted with the routine
monitoring reports for the month in which the sample results are not
available.
(b) Turbidity
limits.
(i) The purveyor shall ensure that the
turbidity level in representative source water samples taken before primary
disinfection does not exceed 5.0 NTU.
(ii) A system failing to meet the turbidity
requirements in (b)(i) of this subsection may remain unfiltered, if:
(A) The purveyor demonstrates to the
department's satisfaction that the most recent turbidity event was caused by
unusual and unpredictable circumstances; and
(B) Including the most recent turbidity
event, there have not been more than:
(I) Two
turbidity events in the twelve previous calendar months the system served water
to the public; or
(II) Five
turbidity events in the one-hundred-twenty previous calendar months the system
served water to the public.
(iii) The purveyor of a system experiencing a
turbidity event shall submit a written report to the department documenting why
the turbidity event(s) occurred. The purveyor shall submit the report with the
routine monitoring reports for the month in which the turbidity event(s)
occurred.
(iv) The purveyor of a
system with alternate, department-approved sources or sufficient treated water
storage may avoid a turbidity event by implementing operational adjustments to
prevent water with a turbidity exceeding 5.0 NTU from being delivered to
consumers.
(v) When an alternate
source or treated water storage is used during periods when the turbidity of
the surface or GWI source exceeds 5.0 NTU, the purveyor shall not put the
surface or GWI source back online, until the source water turbidity is 5.0 NTU
or less.
(3) Site-specific conditions to remain unfiltered.
(a) Level of inactivation.
(i) The purveyor shall ensure that the
Giardia lamblia cyst and virus inactivation levels required
under WAC
246-290-692(1)
are met in at least eleven of the twelve previous calendar months that the
system served water to the public.
(ii) A system failing to meet the
inactivation requirements during two of the twelve previous calendar months
that the system served water to the public may remain unfiltered, if the
purveyor demonstrates to the department's satisfaction that at least one of the
failures was caused by unusual and unpredictable circumstances.
(iii) To make a demonstration, the purveyor
shall submit to the department a written report documenting the reasons for the
failure. The purveyor shall submit the report with the routine monitoring
reports for the month in which the failure occurred.
(b) Redundant disinfection components or
automatic shutoff.
The purveyor shall ensure that the requirement for redundant disinfection system components or automatic shut-off of water to the distribution system under WAC 246-290-692(3) is met at all times the system serves water to the public.
(c) Disinfectant residual entering the
distribution system.
(i) The purveyor shall
ensure that the requirement for having a residual entering the distribution
system under WAC
246-290-692(4)
is met at all times the system serves water to the public.
(ii) A system failing to meet the
disinfection requirement under (c)(i) of this subsection may remain unfiltered,
if the purveyor demonstrates to the department's satisfaction that the failure
was caused by unusual and unpredictable circumstances.
(iii) To make a demonstration, the purveyor
shall submit to the department a written report documenting the reasons for the
failure. The purveyor shall submit the report with the routine monitoring
reports for the month in which the failure occurred.
(d) Disinfectant residuals within the
distribution system.
(i) The purveyor shall
ensure that the requirement for maintaining a residual within the distribution
system under WAC
246-290-692(5)
is met on an ongoing basis.
(ii) A
system failing to meet the disinfection requirements under (d)(i) of this
subsection may remain unfiltered, if the purveyor demonstrates to the
department's satisfaction that the failure was caused by something other than a
deficiency in source water treatment.
(iii) To make a demonstration, the purveyor
shall submit to the department a written report documenting the reasons for the
failure. The purveyor shall submit the report with the routine monitoring
reports for the month in which the failure occurred.
(e) Watershed control.
(i) The purveyor shall develop and implement
a department-approved watershed control program.
(ii) The purveyor shall monitor, limit, and
control all facilities and activities in the watershed affecting source quality
to preclude degradation of the physical, chemical, microbiological (including
viral contamination and contamination by Cryptosporidium
oocysts), and radiological quality of the source. The purveyor shall
demonstrate, through ownership and/or written agreements acceptable to the
department, control of all human activities that may adversely impact source
quality.
(iii) At a minimum, the
purveyor's watershed control program shall:
(A) Characterize the watershed hydrology and
land ownership;
(B) Identify
watershed characteristics and activities that may adversely affect source water
quality; and
(C) Monitor the
occurrence of activities that may adversely affect source water
quality.
(iv) If the
department determines significant changes have occurred in the watershed, the
purveyor shall submit, within ninety days of notification, an updated watershed
control program to the department for review and approval.
(v) The department may require an unfiltered
system to conduct additional monitoring to demonstrate the adequacy of the
watershed control program.
(vi) A
purveyor shall be considered out of compliance when failing to:
(A) Have a department-approved watershed
control program;
(B) Implement the
watershed control program to the satisfaction of the department; or
(C) Conduct additional monitoring as directed
by the department.
(f) On-site inspections.
(i) The department shall conduct on-site
inspections to assess watershed control and disinfection treatment.
(ii) The department shall conduct annual
inspections unless more frequent inspections are deemed necessary to protect
the health of consumers served by the system.
(iii) For a system to remain unfiltered, the
on-site inspection shall indicate to the department's satisfaction that the
watershed control program and disinfection treatment comply with (e) of this
subsection and WAC
246-290-692,
respectively.
(iv) The purveyor
with unsatisfactory on-site inspection results shall take action as directed by
the department in accordance with a department-established schedule.
(g) Waterborne disease outbreak.
(i) To remain unfiltered, a system shall not
have been identified by the department as the cause of a waterborne disease
outbreak attributable to a failure in treatment of the surface or GWI
source.
(ii) The purveyor of a
system identified by the department as the cause of a waterborne disease
outbreak may remain unfiltered, if the purveyor demonstrates to the
department's satisfaction that system facilities and/or operations have been
sufficiently modified to prevent another water-borne disease
outbreak.
(h)
E.
coli MCL.
(i) For a system to remain
unfiltered, the purveyor shall ensure that the MCL for E. coli
under WAC
246-290-310 is met in at least
eleven of the twelve previous calendar months the system served water to the
public.
(ii) A system failing to
meet the criteria in (i) of this subsection, may remain unfiltered, if the
purveyor demonstrates to the department's satisfaction that the E.
coli MCL violations were not caused by a deficiency in source water
treatment.
(iii) The department
shall determine the adequacy of source water treatment based on results of
total coliform monitoring at the entry to the distribution system in accordance
with WAC 246-290-694(3).
(i) Disinfectant residuals MRDL
and disinfection byproducts MCLs - Monitoring and compliance.
For a system to remain unfiltered, the purveyor shall comply with the monitoring and MCL requirements under WAC 246-290-300(6) and 246-290-310(5) and (6), respectively.
(j) Laboratory services.
(i) For a system to remain unfiltered, the
purveyor shall retain the services of the public health laboratory or another
laboratory certified by the department to analyze samples for total and fecal
coliform. Laboratory services shall be available on an as needed basis, seven
days a week, including holidays. The purveyor shall identify in the annual
comprehensive report required under WAC
246-290-696 the certified
laboratory providing these services.
(ii) The department may waive this
requirement, if the purveyor demonstrates to the department's satisfaction that
an alternate, department-approved source is used when the turbidity of the
surface or GWI source exceeds 1.0 NTU.
Statutory Authority: RCW 70.119A.180 and 43.20.050. 08-03-061, § 246-290-690, filed 1/14/08, effective 2/14/08. Statutory Authority: RCW 43.20.050(2) and (3) and 70.119A.080. 03-08-037, § 246-290-690, filed 3/27/03, effective 4/27/03. Statutory Authority: RCW 43.02.050 [43.20.050]. 99-07-021, § 246-290-690, filed 3/9/99, effective 4/9/99. Statutory Authority: RCW 43.20.050. 93-08-011 (Order 352B), § 246-290-690, filed 3/25/93, effective 4/25/93.
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