[Code of Federal Regulations]
[Title 40, Volume 19]
[Revised as of July 1, 2002]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR141.21]

[Page 345-352]
 
                   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

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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 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

[[Page 347]]

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 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

[[Page 348]]

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)-(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

[[Page 349]]

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 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.

[[Page 350]]

    (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                                                                     9221A, B
                                                 Technique 3,4,5.
                                                Total Coliform....................                                                                  9222
                                                Membrane Filter...................                                                               A, B, C
                                                Technique \6\.....................
                                                Presence-Absence..................                                                                  9221
                                                (P-A) Coliform Test \5,7\.........
                                                ONPG-MUG Test \8\.................                                                                  9223
                                                Colisure Test \9\
                                                E*Colite[reg] Test \10\
                                                m-ColiBlue24[reg] Test \11\
--------------------------------------------------------------------------------------------------------------------------------------------------------
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 and 11 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, 1200 Pennsylvania Ave., NW., Washington, DC 20460
  (Telephone: 202-260-3027); or at the Office of Federal Register, 800 North Capitol Street, NW, Suite 700, Washington, D.C. 20408.
\1\ Methods 9221 A, B; 9222 A, B, C; 9221 D and 9223 are contained in Standard Methods for the Examination of Water and Wastewater, 18th edition (1992)
  and 19th edition (1995) American Public Health Association, 1015 Fifteenth Street NW, Washington, D.C. 20005; either edition 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.
\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-4100), 401 M. Street SW, Washington, DC 20460, EPA/600/J-99/225.
\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 Colilert 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).

    (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

[[Page 351]]

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 and in 
the 19th edition, 1995; either edition 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 [mu]g/ml of 4-methylumbelliferyl-
beta-D-glucuronide (MUG) (final concentration). EC medium is described 
in Method 9221 E as referenced in paragraph (f)(5) of this section. MUG 
may be added to EC medium before autoclaving. EC medium supplemented 
with 50 [mu]g/ml of MUG is commercially available. At least 10 ml of EC 
medium supplemented with MUG must be used. The inner inverted 
fermentation tube may be omitted. The procedure for transferring a total 
coliform-positive culture to EC medium supplemented with MUG shall be as 
specified in paragraph (f)(5) of this section for transferring a total 
coliform-positive culture to EC medium. Observe fluorescence with an 
ultraviolet light (366 nm) in the dark after incubating tube at 44.5 
 0.2  deg.C for 24  2 hours; or
    (ii) Nutrient agar supplemented with 100 [mu]g/ml 4-
methylumbelliferyl-beta-D-glucuronide (MUG) (final concentration). 
Nutrient Agar is described in Method 9221 B (paragraph 3) in Standard 
Methods for the Examination of Water and Wastewater, 18th edition, 1992 
and in the 19th edition, 1995; either edition may be used. This test is 
used to determine if a total coliform-positive sample, as determined by 
the Membrane Filter Technique or any other method in which a membrane 
filter is used, contains E. coli. Transfer the membrane filter 
containing a total coliform colony(ies) to nutrient agar supplemented 
with 100 [mu]g/ml (final concentration) of MUG. After incubating the 
agar plate at 35  deg.C for 4 hours, 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.
    (7) As an option to paragraph (f)(6)(iii) of this section, a system 
with a total coliform-positive, 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 +

[[Page 352]]

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 and 19th editions) may be obtained from the 
American Public Health Association et al.; 1015 Fifteenth Street NW., 
Washington, DC 20005. Copies of the methods set forth in Microbiological 
Methods for Monitoring the Environment, Water and Wastes may be obtained 
from ORD Publications, U.S. EPA, 26 W. Martin Luther King Drive, 
Cincinnati, Ohio 45268. 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 Office of the 
Federal Register; 800 North Capitol Street, NW., suite 700, Washington, 
DC.
    (g) Response to violation. (1) A public 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 business 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]