[Code of Federal Regulations]
[Title 40, Volume 22]
[Revised as of July 1, 2005]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR141.21]
[Page 354-361]
TITLE 40--PROTECTION OF ENVIRONMENT
CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
PART 141_NATIONAL PRIMARY DRINKING WATER REGULATIONS--Table of Contents
Subpart C_Monitoring and Analytical Requirements
Sec. 141.21 Coliform sampling.
(a) Routine monitoring. (1) Public water systems must collect total
coliform samples at sites which are representative of water throughout
the distribution system according to a written sample siting plan. These
plans are subject to State review and revision.
(2) The monitoring frequency for total coliforms for community water
systems is based on the population served by the system, as follows:
Total Coliform Monitoring Frequency for Community Water Systems
------------------------------------------------------------------------
Minimum
number of
Population served samples
per month
------------------------------------------------------------------------
25 to 1,000 \1\.............................................. 1
1,001 to 2,500............................................... 2
2,501 to 3,300............................................... 3
3,301 to 4,100............................................... 4
4,101 to 4,900............................................... 5
4,901 to 5,800............................................... 6
5,801 to 6,700............................................... 7
6,701 to 7,600............................................... 8
7,601 to 8,500............................................... 9
8,501 to 12,900.............................................. 10
12,901 to 17,200............................................. 15
17,201 to 21,500............................................. 20
21,501 to 25,000............................................. 25
25,001 to 33,000............................................. 30
33,001 to 41,000............................................. 40
41,001 to 50,000............................................. 50
50,001 to 59,000............................................. 60
59,001 to 70,000............................................. 70
70,001 to 83,000............................................. 80
83,001 to 96,000............................................. 90
96,001 to 130,000............................................ 100
130,001 to 220,000........................................... 120
220,001 to 320,000........................................... 150
320,001 to 450,000........................................... 180
450,001 to 600,000........................................... 210
600,001 to 780,000........................................... 240
780,001 to 970,000........................................... 270
970,001 to 1,230,000......................................... 300
1,230,001 to 1,520,000....................................... 330
1,520,001 to 1,850,000....................................... 360
1,850,001 to 2,270,000....................................... 390
2,270,001 to 3,020,000....................................... 420
3,020,001 to 3,960,000....................................... 450
3,960,001 or more............................................ 480
------------------------------------------------------------------------
\1\ Includes public water systems which have at least 15 service
connections, but serve fewer than 25 persons.
If a community water system serving 25 to 1,000 persons has no history
of total coliform contamination in its current configuration and a
sanitary survey conducted in the past five years shows that the system
is supplied solely by a protected groundwater source and is free of
sanitary defects, the State may reduce the monitoring frequency
specified above, except that in no case may the State reduce the
monitoring frequency to less than one sample per quarter. The State must
approve the reduced monitoring frequency in writing.
(3) The monitoring frequency for total coliforms for non-community
water systems is as follows:
(i) A non-community water system using only ground water (except
ground water under the direct influence of surface water, as defined in
Sec. 141.2) and serving 1,000 persons or fewer must monitor each
calendar
[[Page 355]]
quarter that the system provides water to the public, except that the
State may reduce this monitoring frequency, in writing, if a sanitary
survey shows that the system is free of sanitary defects. Beginning June
29, 1994, the State cannot reduce the monitoring frequency for a non-
community water system using only ground water (except ground water
under the direct influence of surface water, as defined in Sec. 141.2)
and serving 1,000 persons or fewer to less than once/year.
(ii) A non-community water system using only ground water (except
ground water under the direct influence of surface water, as defined in
Sec. 141.2) and serving more than 1,000 persons during any month must
monitor at the same frequency as a like-sized community water system, as
specified in paragraph (a)(2) of this section, except the State may
reduce this monitoring frequency, in writing, for any month the system
serves 1,000 persons or fewer. The State cannot reduce the monitoring
frequency to less than once/year. For systems using ground water under
the direct influence of surface water, paragraph (a)(3)(iv) of this
section applies.
(iii) A non-community water system using surface water, in total or
in part, must monitor at the same frequency as a like-sized community
water system, as specified in paragraph (a)(2) of this section,
regardless of the number of persons it serves.
(iv) A non-community water system using ground water under the
direct influence of surface water, as defined in Sec. 141.2, must
monitor at the same frequency as a like-sized community water system, as
specified in paragraph (a)(2) of this section. The system must begin
monitoring at this frequency beginning six months after the State
determines that the ground water is under the direct influence of
surface water.
(4) The public water system must collect samples at regular time
intervals throughout the month, except that a system which uses only
ground water (except ground water under the direct influence of surface
water, as defined in Sec. 141.2), and serves 4,900 persons or fewer,
may collect all required samples on a single day if they are taken from
different sites.
(5) A public water system that uses surface water or ground water
under the direct influence of surface water, as defined in Sec. 141.2,
and does not practice filtration in compliance with Subpart H must
collect at least one sample near the first service connection each day
the turbidity level of the source water, measured as specified in Sec.
141.74(b)(2), exceeds 1 NTU. This sample must be analyzed for the
presence of total coliforms. When one or more turbidity measurements in
any day exceed 1 NTU, the system must collect this coliform sample
within 24 hours of the first exceedance, unless the State determines
that the system, for logistical reasons outside the system's control,
cannot have the sample analyzed within 30 hours of collection. Sample
results from this coliform monitoring must be included in determining
compliance with the MCL for total coliforms in Sec. 141.63.
(6) Special purpose samples, such as those taken to determine
whether disinfection practices are sufficient following pipe placement,
replacement, or repair, shall not be used to determine compliance with
the MCL for total coliforms in Sec. 141.63. Repeat samples taken
pursuant to paragraph (b) of this section are not considered special
purpose samples, and must be used to determine compliance with the MCL
for total coliforms in Sec. 141.63.
(b) Repeat monitoring. (1) If a routine sample is total coliform-
positive, the public water system must collect a set of repeat samples
within 24 hours of being notified of the positive result. A system which
collects more than one routine sample/month must collect no fewer than
three repeat samples for each total coliform-positive sample found. A
system which collects one routine sample/month or fewer must collect no
fewer than four repeat samples for each total coliform-positive sample
found. The State may extend the 24-hour limit on a case-by-case basis if
the system has a logistical problem in collecting the repeat samples
within 24 hours that is beyond its control. In the case of an extension,
the State must specify how much time
[[Page 356]]
the system has to collect the repeat samples.
(2) The system must collect at least one repeat sample from the
sampling tap where the original total coliform-positive sample was
taken, and at least one repeat sample at a tap within five service
connections upstream and at least one repeat sample at a tap within five
service connections downstream of the original sampling site. If a total
coliform-positive sample is at the end of the distribution system, or
one away from the end of the distribution system, the State may waive
the requirement to collect at least one repeat sample upstream or
downstream of the original sampling site.
(3) The system must collect all repeat samples on the same day,
except that the State may allow a system with a single service
connection to collect the required set of repeat samples over a four-day
period or to collect a larger volume repeat sample(s) in one or more
sample containers of any size, as long as the total volume collected is
at least 400 ml (300 ml for systems which collect more than one routine
sample/month).
(4) If one or more repeat samples in the set is total coliform-
positive, the public water system must collect an additional set of
repeat samples in the manner specified in paragraphs (b) (1)-(3) of this
section. The additional samples must be collected within 24 hours of
being notified of the positive result, unless the State extends the
limit as provided in paragraph (b)(1) of this section. The system must
repeat this process until either total coliforms are not detected in one
complete set of repeat samples or the system determines that the MCL for
total coliforms in Sec. 141.63 has been exceeded and notifies the
State.
(5) If a system collecting fewer than five routine samples/month has
one or more total coliform-positive samples and the State does not
invalidate the sample(s) under paragraph (c) of this section, it must
collect at least five routine samples during the next month the system
provides water to the public, except that the State may waive this
requirement if the conditions of paragraph (b)(5) (i) or (ii) of this
section are met. The State cannot waive the requirement for a system to
collect repeat samples in paragraphs (b) (1)-(4) of this section.
(i) The State may waive the requirement to collect five routine
samples the next month the system provides water to the public if the
State, or an agent approved by the State, performs a site visit before
the end of the next month 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 State to determine whether additional
monitoring and/or any corrective action is needed. The State cannot
approve an employee of the system to perform this site visit, even if
the employee is an agent approved by the State to perform sanitary
surveys.
(ii) The State may waive the requirement to collect five routine
samples the next month the system provides water to the public if the
State has determined why the sample was total coliform-positive and
establishes that the system has corrected the problem or will correct
the problem before the end of the next month the system serves water to
the public. In this case, the State 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 State official who
recommends such a decision, and make this document available to the EPA
and 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. The State cannot waive
the requirement to collect five routine samples the next month the
system provides water to the public solely on the grounds that all
repeat samples are total coliform-negative. Under this paragraph, a
system must still take at least one routine sample before the end of the
next month it serves water to the public and use it to determine
compliance with the MCL for total coliforms in Sec. 141.63, unless the
State has determined that the system has corrected the contamination
problem before the system took the set of repeat samples required in
paragraphs (b) (1)-
[[Page 357]]
(4) of this section, and all repeat samples were total coliform-
negative.
(6) After a system collects a routine sample and before it learns
the results of the analysis of that sample, if it collects another
routine sample(s) from within five adjacent service connections of the
initial sample, and the initial sample, after analysis, is found to
contain total coliforms, then the system may count the subsequent
sample(s) as a repeat sample instead of as a routine sample.
(7) Results of all routine and repeat samples not invalidated by the
State must be included in determining compliance with the MCL for total
coliforms in Sec. 141.63.
(c) Invalidation of total coliform samples. A total coliform-
positive sample invalidated under this paragraph (c) does not count
towards meeting the minimum monitoring requirements of this section.
(1) The State may invalidate a total coliform-positive sample only
if the conditions of paragraph (c)(1) (i), (ii), or (iii) of this
section are met.
(i) The laboratory establishes that improper sample analysis caused
the total coliform-positive result.
(ii) The State, on the basis of the results of repeat samples
collected as required by paragraphs (b) (1) through (4) of this section,
determines that the total coliform-positive sample resulted from a
domestic or other non-distribution system plumbing problem. The State
cannot invalidate a sample on the basis of repeat sample results unless
all repeat sample(s) collected at the same tap as the original total
coliform-positive sample are also total coliform-positive, and all
repeat samples collected within five service connections of the original
tap are total coliform-negative (e.g., a State cannot invalidate a total
coliform-positive sample on the basis of repeat samples if all the
repeat samples are total coliform-negative, or if the public water
system has only one service connection).
(iii) The State has substantial grounds to believe that a total
coliform-positive result is due to a circumstance or condition which
does not reflect water quality in the distribution system. In this case,
the system must still collect all repeat samples required under
paragraphs (b) (1)-(4) of this section, and use them to determine
compliance with the MCL for total coliforms in Sec. 141.63. To
invalidate a total coliform-positive sample under this paragraph, the
decision with the rationale for the decision must be documented in
writing, and approved and signed by the supervisor of the State official
who recommended the decision. The State must make this document
available to EPA and the public. The written documentation must state
the specific cause of the total coliform-positive sample, and what
action the system has taken, or will take, to correct this problem. The
State may not invalidate a total coliform-positive sample solely on the
grounds that all repeat samples are total coliform-negative.
(2) A laboratory must invalidate a total coliform sample (unless
total coliforms are detected) if the sample produces a turbid culture in
the absence of gas production using an analytical method where gas
formation is examined (e.g., the Multiple-Tube Fermentation Technique),
produces a turbid culture in the absence of an acid reaction in the
Presence-Absence (P-A) Coliform Test, or exhibits confluent growth or
produces colonies too numerous to count with an analytical method using
a membrane filter (e.g., Membrane Filter Technique). If a laboratory
invalidates a sample because of such interference, the system must
collect another sample from the same location as the original sample
within 24 hours of being notified of the interference problem, and have
it analyzed for the presence of total coliforms. The system must
continue to re-sample within 24 hours and have the samples analyzed
until it obtains a valid result. The State may waive the 24-hour time
limit on a case-by-case basis.
(d) Sanitary surveys. (1)(i) Public water systems which do not
collect five or more routine samples/month must undergo an initial
sanitary survey by June 29, 1994, for community public water systems and
June 29, 1999, for non-community water systems. Thereafter, systems must
undergo another
[[Page 358]]
sanitary survey every five years, except that non-community water
systems using only protected and disinfected ground water, as defined by
the State, must undergo subsequent sanitary surveys at least every ten
years after the initial sanitary survey. The State must review the
results of each sanitary survey to determine whether the existing
monitoring frequency is adequate and what additional measures, if any,
the system needs to undertake to improve drinking water quality.
(ii) In conducting a sanitary survey of a system using ground water
in a State having an EPA-approved wellhead protection program under
section 1428 of the Safe Drinking Water Act, information on sources of
contamination within the delineated wellhead protection area that was
collected in the course of developing and implementing the program
should be considered instead of collecting new information, if the
information was collected since the last time the system was subject to
a sanitary survey.
(2) Sanitary surveys must be performed by the State or an agent
approved by the State. The system is responsible for ensuring the survey
takes place.
(e) Fecal coliforms/Escherichia coli (E. coli) testing. (1) If any
routine or repeat sample is total coliform-positive, the system must
analyze that total coliform-positive culture medium to determine if
fecal coliforms are present, except that the system may test for E. coli
in lieu of fecal coliforms. If fecal coliforms or E. coli are present,
the system must notify the State by the end of the day when the system
is notified of the test result, unless the system is notified of the
result after the State office is closed, in which case the system must
notify the State before the end of the next business day.
(2) The State has the discretion to allow a public water system, on
a case-by-case basis, to forgo fecal coliform or E. coli testing on a
total coliform-positive sample if that system assumes that the total
coliform-positive sample is fecal coliform-positive or E. coli-positive.
Accordingly, the system must notify the State as specified in paragraph
(e)(1) of this section and the provisions of Sec. 141.63(b) apply.
(f) Analytical methodology. (1) The standard sample volume required
for total coliform analysis, regardless of analytical method used, is
100 ml.
(2) Public water systems need only determine the presence or absence
of total coliforms; a determination of total coliform density is not
required.
(3) Public water systems must conduct total coliform analyses in
accordance with one of the analytical methods in the following table.
----------------------------------------------------------------------------------------------------------------
Organism Methodology\12\ Citation\1\
----------------------------------------------------------------------------------------------------------------
Total Coliforms \2\................... Total Coliform Fermentation Technique 3, 9221A, B.
4, 5.
Total Coliform Membrane Filter Technique 9222A, B, C.
\6\.
Presence-Absence (P-A) Coliform Test 5, 9221D.
7.
ONPG-MUG Test \8\....................... 9223.
Colisure Test \9\. ..............................
E*Colite [reg] Test \10\. ..............................
m-ColiBlue24 [reg] Test \11\. ..............................
Readycult [reg] Coliforms 100 Presence/ ..............................
Absence Test \13\.
Membrane Filter Technique using ..............................
Chromocult [reg] Coliform Agar\14\.
Colitag [reg] Test \15\. ..............................
----------------------------------------------------------------------------------------------------------------
The procedures shall be done in accordance with the documents listed below. The incorporation by reference of
the following documents listed in footnotes 1, 6, 8, 9, 10 , 11, 13, 14 and 15 was approved by the Director of
the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51. Copies of the documents may be
obtained from the sources listed below. Information regarding obtaining these documents can be obtained from
the Safe Drinking Water Hotline at 800-426-4791. Documents may be inspected at EPA's Drinking Water Docket,
EPA West, 1301 Constitution Avenue, NW., EPA West, Room B102, Washington DC 20460 (Telephone: 202-566-2426);
or at the National Archives and Records Administration (NARA). For information on the availability of this
material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal--register/code--of--federal--
regulations/ibr--locations.html.
\1\ Standard Methods for the Examination of Water and Wastewater, 18th edition (1992), 19th edition (1995), or
20th edition (1998). American Public Health Association, 1015 Fifteenth Street, NW., Washington, DC 20005. The
cited methods published in any of these three editions may be used.
\2\ The time from sample collection to initiation of analysis may not exceed 30 hours. Systems are encouraged
but not required to hold samples below 10 deg. C during transit.
\3\ Lactose broth, as commercially available, may be used in lieu of lauryl tryptose broth, if the system
conducts at least 25 parallel tests between this medium and lauryl tryptose broth using the water normally
tested, and this comparison demonstrates that the false-positive rate and false-negative rate for total
coliform, using lactose broth, is less than 10 percent.
\4\ If inverted tubes are used to detect gas production, the media should cover these tubes at least one-half to
two-thirds after the sample is added.
\5\ No requirement exists to run the completed phase on 10 percent of all total coliform-positive confirmed
tubes.
[[Page 359]]
\6\ MI agar also may be used. Preparation and use of MI agar is set forth in the article, ``New medium for the
simultaneous detection of total coliform and Escherichia coli in water'' by Brenner, K.P., et. al., 1993,
Appl. Environ. Microbiol. 59:3534-3544. Also available from the Office of Water Resource Center (RC-4100T),
1200 Pennsylvania Avenue, NW., Washington, DC 20460, EPA/600/J-99/225. Verification of colonies is not
required.
\7\ Six-times formulation strength may be used if the medium is filter-sterilized rather than autoclaved.
\8\ The ONPG-MUG Test is also known as the Autoanalysis Collect System.
\9\ A description of the Colisure Test, Feb 28, 1994, may be obtained from IDEXX Laboratories, Inc., One IDEXX
Drive, Westbrook, Maine 04092. The Colisure Test may be read after an incubation time of 24 hours.
\10\ A description of the E*Colite [reg] Test, ``Presence/Absence for Coliforms and E. Coli in Water,'' Dec 21,
1997, is available from Charm Sciences, Inc., 36 Franklin Street, Malden, MA 02148-4120.
\11\ A description of the m-ColiBlue24 [reg] Test, Aug 17, 1999, is available from the Hach Company, 100 Dayton
Avenue, Ames, IA 50010.
\12\ EPA strongly recommends that laboratories evaluate the false-positive and negative rates for the method(s)
they use for monitoring total coliforms. EPA also encourages laboratories to establish false-positive and
false-negative rates within their own laboratory and sample matrix (drinking water or source water) with the
intent that if the method they choose has an unacceptable false-positive or negative rate, another method can
be used. The Agency suggests that laboratories perform these studies on a minimum of 5% of all total coliform-
positive samples, except for those methods where verification/confirmation is already required, e.g., the M-
Endo and LES Endo Membrane Filter Tests, Standard Total Coliform Fermentation Technique, and Presence-Absence
Coliform Test. Methods for establishing false-positive and negative-rates may be based on lactose
fermentation, the rapid test for [beta]-galactosidase and cytochrome oxidase, multi-test identification
systems, or equivalent confirmation tests. False-positive and false-negative information is often available in
published studies and/or from the manufacturer(s).
\13\ The Readycult [reg] Coliforms 100 Presence/Absence Test is described in the document, ``Readycult [reg]
Coliforms 100 Presence/Absence Test for Detection and Identification of Coliform Bacteria and Escherichla coli
in Finished Waters'', November 2000, Version 1.0, available from EM Science (an affiliate of Merck KGgA,
Darmstadt Germany), 480 S. Democrat Road, Gibbstown, NJ 08027-1297. Telephone number is (800) 222-0342, e-mail
address is: adellenbusch@emscience.com.
\14\ Membrane Filter Technique using Chromocult [reg] Coliform Agar is described in the document, ``Chromocult
[reg] Coliform Agar Presence/Absence Membrane Filter Test Method for Detection and Identification of Coliform
Bacteria and Escherichla coli in Finished Waters'', November 2000, Version 1.0, available from EM Science (an
affiliate of Merck KGgA, Darmstadt Germany), 480 S. Democrat Road, Gibbstown, NJ 08027-1297. Telephone number
is (800) 222-0342, e-mail address is: adellenbusch@emscience.com.
\15\ Colitag [reg] product for the determination of the presence/absence of total coliforms and E. coli is
described in ``Colitag [reg] Product as a Test for Detection and Identification of Coliforms and E. coli
Bacteria in Drinking Water and Source Water as Required in National Primary Drinking Water Regulations,''
August 2001, available from CPI International, Inc., 5580 Skylane Blvd., Santa Rosa, CA, 95403, telephone
(800) 878-7654, Fax (707) 545-7901, Internet address http://www.cpiinternational.com.
(4) [Reserved]
(5) Public water systems must conduct fecal coliform analysis in
accordance with the following procedure. When the MTF Technique or
Presence-Absence (PA) Coliform Test is used to test for total coliforms,
shake the lactose-positive presumptive tube or P-A vigorously and
transfer the growth with a sterile 3-mm loop or sterile applicator stick
into brilliant green lactose bile broth and EC medium to determine the
presence of total and fecal coliforms, respectively. For EPA-approved
analytical methods which use a membrane filter, transfer the total
coliform-positive culture by one of the following methods: remove the
membrane containing the total coliform colonies from the substrate with
a sterile forceps and carefully curl and insert the membrane into a tube
of EC medium (the laboratory may first remove a small portion of
selected colonies for verification), swab the entire membrane filter
surface with a sterile cotton swab and transfer the inoculum to EC
medium (do not leave the cotton swab in the EC medium), or inoculate
individual total coliform-positive colonies into EC Medium. Gently shake
the inoculated tubes of EC medium to insure adequate mixing and incubate
in a waterbath at 44.5 0.2 [deg]C for 24 2 hours. Gas production of any amount in the inner
fermentation tube of the EC medium indicates a positive fecal coliform
test. The preparation of EC medium is described in Method 9221E
(paragraph 1a) in Standard Methods for the Examination of Water and
Wastewater, 18th edition (1992), 19th edition (1995), and 20th edition
(1998); the cited method in any one of these three editions may be used.
Public water systems need only determine the presence or absence of
fecal coliforms; a determination of fecal coliform density is not
required.
(6) Public water systems must conduct analysis of Escherichia coli
in accordance with one of the following analytical methods:
(i) EC medium supplemented with 50 [micro]g/mL of 4-
methylumbelliferyl-beta-D-glucuronide (MUG) (final concentration), as
described in Method 9222G in Standard Methods for the Examination of
Water and Wastewater, 19th edition (1995) and 20th edition (1998).
Either edition may be used. Alternatively, the 18th edition (1992) may
be used if at least 10 mL of EC medium, as described in paragraph (f)(5)
of this section, is supplemented with 50 [micro]g/mL of MUG before
autoclaving. The inner inverted fermentation tube may be omitted. If
[[Page 360]]
the 18th edition is used, apply the procedure in paragraph (f)(5) of
this section for transferring a total coliform-positive culture to EC
medium supplemented with MUG, incubate the tube at 44.5 0.2 [deg]C for 24 2 hours, and
then observe fluorescence with an ultraviolet light (366 nm) in the
dark. If fluorescence is visible, E. coli are present.
(ii) Nutrient agar supplemented with 100 [micro]g/mL of 4-
methylumbelliferyl-beta-D-glucuronide (MUG) (final concentration), as
described in Method 9222G in Standard Methods for the Examination of
Water and Wastewater, 19th edition (1995) and 20th edition (1998).
Either edition may be used for determining if a total coliform-positive
sample, as determined by a membrane filter technique, contains E. coli.
Alternatively, the 18th edition (1992) may be used if the membrane
filter containing a total coliform-positive colony(ies) is transferred
to nutrient agar, as described in Method 9221B (paragraph 3) of Standard
Methods (18th edition), supplemented with 100 [micro]g/mL of MUG. If the
18th edition is used, incubate the agar plate at 35 [deg]C for 4 hours
and then observe the colony(ies) under ultraviolet light (366 nm) in the
dark for fluorescence. If fluorescence is visible, E. coli are present.
(iii) Minimal Medium ONPG-MUG (MMO-MUG) Test, as set forth in the
article ``National Field Evaluation of a Defined Substrate Method for
the Simultaneous Detection of Total Coliforms and Escherichia coli from
Drinking Water: Comparison with Presence-Absence Techniques'' (Edberg et
al.), Applied and Environmental Microbiology, Volume 55, pp. 1003-1008,
April 1989. (Note: The Autoanalysis Colilert System is an MMO-MUG test).
If the MMO-MUG test is total coliform-positive after a 24-hour
incubation, test the medium for fluorescence with a 366-nm ultraviolet
light (preferably with a 6-watt lamp) in the dark. If fluorescence is
observed, the sample is E. coli-positive. If fluorescence is
questionable (cannot be definitively read) after 24 hours incubation,
incubate the culture for an additional four hours (but not to exceed 28
hours total), and again test the medium for fluorescence. The MMO-MUG
Test with hepes buffer in lieu of phosphate buffer is the only approved
formulation for the detection of E. coli.
(iv) The Colisure Test. A description of the Colisure Test may be
obtained from the Millipore Corporation, Technical Services Department,
80 Ashby Road, Bedford, MA 01730.
(v) The membrane filter method with MI agar, a description of which
is cited in footnote 6 to the table in paragraph (f)(3) of this section.
(vi) E*Colite [reg] Test, a description of which is cited
in footnote 10 to the table at paragraph (f)(3) of this section.
(vii) m-ColiBlue24 [reg] Test, a description of which is
cited in footnote 11 to the table in paragraph (f)(3) of this section.
(viii) Readycult [reg] Coliforms 100 Presence/Absence
Test, a description of which is cited in footnote 13 to the table at
paragraph (f)(3) of this section.
(ix) Membrane Filter Technique using Chromocult [reg]
Coliform Agar, a description of which is cited in footnote 14 to the
table at paragraph (f)(3) of this section.
(x) Colitag [reg], a description of which is cited in
footnote 15 to the table at paragraph (f)(3) of this section.
(7) As an option to paragraph (f)(6)(iii) of this section, a system
with a total coliform-pos i tive, MUG-negative, MMO-MUG test may further
analyze the culture for the presence of E. coli by transferring a 0.1
ml, 28-hour MMO-MUG culture to EC Medium + MUG with a pipet. The
formulation and incubation conditions of EC Medium + MUG, and
observation of the results are described in paragraph (f)(6)(i) of this
section.
(8) The following materials are incorporated by reference in this
section with the approval of the Director of the Federal Register in
accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies of the
analytical methods cited in Standard Methods for the Examination of
Water and Wastewater (18th, 19th, and 20th editions) may be obtained
from the American Public Health Association et al.; 1015 Fifteenth
Street, NW., Washington, DC 20005-2605. Copies of the MMO-MUG Test, as
set forth in the article ``National Field Evaluation of a Defined
Substrate Method for the Simultaneous Enumeration of Total Coliforms and
Escherichia coli from
[[Page 361]]
Drinking Water: Comparison with the Standard Multiple Tube Fermentation
Method'' (Edberg et al.) may be obtained from the American Water Works
Association Research Foundation, 6666 West Quincy Avenue, Denver, CO
80235. Copies of the MMO-MUG Test as set forth in the article ``National
Field Evaluation of a Defined Substrate Method for the Simultaneous
Enumeration of Total Coliforms and Escherichia coli from Drinking Water:
Comparison with the Standard Multiple Tube Fermentation Method'' (Edberg
et al.) may be obtained from the American Water Works Association
Research Foundation, 6666 West Quincy Avenue, Denver, CO 80235. A
description of the Colisure Test may be obtained from the Millipore
Corp., Technical Services Department, 80 Ashby Road, Bedford, MA 01730.
Copies may be inspected at EPA's Drinking Water Docket; 401 M St., SW.;
Washington, DC 20460, or at the National Archives and Records
Administration (NARA). For information on the availability of this
material at NARA, call 202-741-6030, or go to: http://www.archives.gov/
federal--register/code--of--federal--regulations/ibr--locations.html.
(g) Response to violation. (1) A pub lic water system which has
exceeded the MCL for total coliforms in Sec. 141.63 must report the
violation to the State no later than the end of the next busi ness day
after it learns of the violation, and notify the public in accordance
with subpart Q.
(2) A public water system which has failed to comply with a coliform
monitoring requirement, including the sanitary survey requirement, must
report the monitoring violation to the State within ten days after the
system discovers the violation, and notify the public in accordance with
subpart Q.
[54 FR 27562, June 29, 1989, as amended at 54 FR 30001, July 17, 1989;
55 FR 25064, June 19, 1990; 56 FR 642, Jan. 8, 1991; 57 FR 1852, Jan.
15, 1992; 57 FR 24747, June 10, 1992; 59 FR 62466, Dec. 5, 1994; 60 FR
34085, June 29, 1995; 64 FR 67461, Dec. 1, 1999; 65 FR 26022, May 4,
2000; 67 FR 65246, Oct. 23, 2002; 67 FR 65896, Oct. 29, 2002; 69 FR
7160, Feb. 13, 2004]