TOTAL COLIFORM SAMPLING FREQUENCY

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					TOTAL COLIFORM MONITORING
               40 CFR 141.21


   TRANSIENT NON-COMMUNITY
     PUBLIC WATER SYSTEMS
                 COLIFORM SAMPLING
                                      CFR 141.21 (a)

• Routine Monitoring
  – Written sample siting plan
    • Sites must represent water throughout distribution
      system
    • Plans subject to State review and revision
          MONITORING FREQUENCY
                Groundwater System
                              CFR 141.21 (a) (3) (i)
  Daily Population: 25 to 1,000 Persons
• Monitor each calendar quarter when water served
  to public
  – Monthly monitoring suggested

• State can reduce monitoring to once/year
  – System must be free of sanitary defects
     MONITORING FREQUENCY
     Groundwater System (continued)
Population Served   Minimum
 (average daily)    Samples/Month*

  1,001 to 2,500         2

  2,501 to 3,300         3

  3,301 to 4,100         4

                      *40 CFR 141.21 (a) (2)
   MONITORING FREQUENCY
Surface Water and GW Under Influence

 Population Served     Minimum
  (average daily)      Samples/Month*
    25 to 1,000               1
   1,001 to 2,500             2
   2,501 to 3,300             3

                     *40 CFR 141.21 (a) (2)
    ROUTINE SAMPLE INTERVALS
                             CFR 141.21 (a) (4)

• PWS must collect samples at regular time
  intervals throughout the month, except GW
  systems serving 4,900 and fewer. Those systems
  may collect all required samples on a single day
  if they are taken from different sites.
ROUTINE SAMPLE COLLECTION
                             Helpful Hints

        Always Collect
        - early in the week
        - early in the month
        - early in the compliance period

Early collection allows time to collect
repeat samples, if routine sample is
total coliform positive.
     FECAL COLIFORM OR E. COLI
   TESTING OF ROUTINE SAMPLES
                                          CFR 141.21 (e)
• Any routine or repeat sample that is TC+ must be
  analyzed for the presence of fecal coliforms or
  E. coli.
  – If FC+ or EC+, the system must notify the State by the
    end of the day when the system is notified of the
    result, unless the State office is closed at that time. In
    such a case, the State must be notified before the end
    of the next business day.
     FC OR EC COLIFORM TESTING
                           CFR 141.21 (e) (continued)

• State may waive fecal or E. coli testing if the system
  assumes the TC+ sample is also FC+ or EC+.
   – State waiver is made on a case-by-case basis
   – System must notify State by the end of the day when
     the system is notified of the result, unless the State
     office is closed at that time. In such a case, the State
     must be notified before the end of the next business
     day.
           REPEAT MONITORING
                              CFR 141.21 (b)
              WHEN?
   • Collect repeats within
1
1
 2
 1
 1   24 hours of being notified
0
1 2
9 3
     of positive routines (State may
84 extend on case by case basis.)
 75
 6

            • Collect all repeats
              on the same day
 REPEAT MONITORING
 HOW MANY?
• If PWS Collects One or Fewer Routines/Month
  – Collect four repeat samples for each TC+ routine
    sample

• If PWS Collects >1 Routine Sample/Month
  – Collect three repeat samples for each TC+ routine
    sample
                 REPEAT MONITORING

  WHERE?
• At least one repeat at tap
  where original TC+ sample taken

• At least one repeat sample within
  five service connections upstream of original site
                REPEAT MONITORING

 WHERE? (continued)
• At least one repeat sample within five service
  connections downstream of original site

• Location of fourth sample collected at the
  discretion of the PWS
              SYSTEMS WITH A SINGLE
               SERVICE CONNECTION
                                  CFR 141.21 (b) (3)

• Samples can be collected in a single large volume
  or as 100ml samples in multiple containers
     – Collect all samples on the same day
                     OR
     – Collect samples over a four day period
        RECOMMENDED REPEAT
        COLLECTION METHOD

• Ideal method is to collect samples over a four day
  period.

• If unable to collect over four days, then collect
  four separate samples spaced throughout a single
  day.
         RECOMMENDED REPEAT
           COLLECTION METHOD
                                      (continued)
• Four separate samples recommended over a
  single large volume sample because:
  – Increases probability of capturing coliforms, if
    present, since contamination may be intermittent
 POSITIVE REPEAT SAMPLES
                           CFR 141.21 (b) (4)
• If one or more repeats is TC+, then collect
  a set of four repeats for each TC+ sample.
   – Repeat process until no detection of TC in
     one set of repeats or the MCL is exceeded
     and State has been notified

• Collect samples within 24 hours of being
  notified of positive results.
   – State may extend on case-by-case basis
            ADDITIONAL ROUTINES
                             CFR 141.21 (b) (5)

If a system collects fewer than five routine
samples/month and has one or more TC+
sample(s) which are not invalidated, it must collect
at least five routine samples during the next
month the system provides water to the public.

The State may waive this requirement on a
case-by-case basis.
STATE WAIVER FOR COLLECTION
   OF ADDITIONAL ROUTINES
State may waive the requirement to collect five
routines the next month the system provides water
in one of the two following cases:
  1. A State approved agent performs a detailed
     site visit before the end of the next month the
     system provides water to the public. The
     inspecting agent cannot be an employee of the
     water system.
                                       141.21 (b) (5) (i)
           STATE WAIVER (continued)
2. The State determines the cause of the TC+ sample
   and establishes that the system has corrected the
   problem before the end of the next month the system
   serves water to the public. If so, the State must
      a. Document the waiver in writing
      b. Approve and sign the document
      c. Make document available to EPA and public
    MAXIMUM CONTAMINANT LEVEL
(MCL) COMPLIANCE DETERMINATION
                              CFR 141.21 (b) (7)

  • All valid routine and repeat results must be
    included in determining compliance with the
    MCL for total coliforms.
  • Invalidated TC+ samples do NOT count toward
    compliance
  (MCLs) FOR MICROBIOLOGICAL
                CONTAMINANTS
                                              CFR 141.63
• The MCL is based on presence/absence of total coliforms
  in a sample.
• Systems collecting fewer than 40 samples/month are in
  compliance with the MCL for TC, if no more than one
  sample collected during a month is TC+.
• Systems collecting at least 40 samples/month are in
  compliance, if no more than 5.0% of the samples
  collected during a month are TC+.
    MCL COMPLIANCE CHART FOR
MICROBIOLOGICAL CONTAMINANTS
Routine Results   Repeat Results    In Compliance?
 TC     FC/EC      TC     FC or      MCL      Acute
                           EC      violation violation
  -       NA      NA       NA         NA        NA
  +        -        -      NA        NO        NO
  +        -       +         -       YES       NO
  +        +        -      NA        NO        NO
  +        +       +         -       YES       YES
  +        +       +        +        YES       YES
  +        -       +        +        YES       YES
STATE INVALIDATION OF TOTAL
        COLIFORM SAMPLES
                      CFR 141.21 (1) (c)(i - iii)
   TC+ Samples Invalidated by State
 • Lab establishes improper analysis caused result
   OR
 • Repeat sample(s) at original TC+ tap are
   positive, all others negative (not so for single
   service connections) OR
 • Positive result is unrelated to water quality in
   distribution system
STATE INVALIDATION OF TOTAL
  COLIFORM SAMPLES (continued)
• If State invalidates because result is unrelated
  to water quality
  – Decision, rationale and corrective action must
    be in writing
  – Approved and signed by supervisor
  – Document available to EPA and public
  – Water system must still collect all repeat samples and
    use them to determine compliance with the MCL
     LAB INVALIDATION OF TOTAL
             COLIFORM SAMPLES
                                      CFR 141.21 (c) (2)
• A lab must invalidate a total coliform sample
  (unless TC+) if test results reveal heterotrophic
  interference (HI).
  – System must collect a replacement sample from the
    same location as the original sample. Collection must
    be within 24 hours of being notified of the HI.
                           HETEROTROPHIC
                            INTERFERENCE
Non-coliform bacteria which are better than coliforms at
surviving in the environment may be present in the sample.
If these organisms are given a chance to grow, they may
out-compete coliforms during analysis and may limit the
analysts ability to detect coliforms. The effect of HI is an
underestimation of coliform numbers or a false negative
result.
          REASONS SAMPLES MAY BE
           REJECTED FOR ANALYSIS
• Old sample (received   • Insufficient quantity
  after 30 hours)
                         • No date/time of collection
• Container broken in
  transit                • Frozen

                         • Leaked

      COLLECT REPLACEMENT SAMPLES
      FOR ALL OF THE ABOVE CASES
        PUBLIC NOTIFICATION (PN)
                      CFR 141.32
 A PN IS REQUIRED WHEN A SYSTEM:
• Fails to Monitor (FTM) for Total Coliforms
  – Routine monitoring
  – Repeat monitoring
  – Additional routine monitoring the month following a
    TC+ routine
• Exceeds the MCL for Total Coliforms
    PN REQUIREMENTS FOR FTM
        FOR TOTAL COLIFORMS
                                         CFR 141.32
• Within three months of the FTM, non-
  community PWS’s must
  – Continuously post the notice in a conspicuous
    place for as long as the violation exists, or
  – Directly deliver the notice by hand
    • Repeat hand delivery every three months for as
      long as the violation exists
        PN REQUIREMENTS FOR
    NON-ACUTE MCL VIOLATIONS
                                           CFR 141.32
• Within 14 days of the TC non-acute violation,
  non-community PWS’s must
  – Continuously post the notice in a conspicuous
    place for as long as the violation exists, or
  – Directly deliver the notice by hand
     • Repeat hand delivery every three months for as
       long as the violation exists
             PN REQUIREMENTS FOR
             ACUTE MCL VIOLATIONS
                                           CFR 141.32
• Within 72 hours of the TC acute violation,
  non-community PWS’s must
  – Continuously post the notice in a conspicuous
    place for as long as the violation exists, or
  – Directly deliver the notice by hand
     • Repeat hand delivery every three months for as
       long as the violation exists
             GENERAL CONTENT OF PN
                                              CFR 141.32
• The PN must provide
  –   A clear explanation of the violation
  –   Potential adverse health effects
  –   Population at risk
  –   Corrective steps taken by the PWS
  –   The need to seek alternative water supplies, if any
  –   Preventative measures the consumer should take
  –   Name and number of a contact person
 PN REPORTING REQUIREMENTS
                  CFR 141.31

• The PWS, within ten days of completion of each
  public notification, shall submit to the State a
  copy of each type of notice that was made
  available to the persons served by the system.
• ALWAYS
 – DRINK UPSTREAM FROM THE HERD!!!

				
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posted:10/9/2011
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