United States
    Environmental Protection
Ground  Water Rule Sample
Collection  and Transport: A Quick
Reference  Guide
                           Overview of the Rule
            Ground Water Rule (GWR) 71 FR 65574, November 8, 2006, Vol. 71, No.
            Correction 71 FR 67427, November 21, 2006, Vol. 71, No. 224
            Reduce the risk of illness caused by microbial contamination in public
            ground water systems (GWSs).
            The GWR establishes a risk-targeted approach to identify GWSs
            susceptible to fecal contamination and requires corrective action to correct
            significant deficiencies and address source water fecal contamination in all
            public GWSs.
            The GWR applies to all public water systems (PWSs) that use ground
            water, including consecutive systems, except that it does not apply to
            PWSs that combine all of their ground water with surface water or with
            ground water under the direct influence of surface water prior to treatment.
                           GWR Situations Requiring Sample Collection and Transport
   The GWR requires that systems that do not provide 4-log treatment of viruses for all
   their ground water sources collect at least one source water sample after detection of
   total coliform in a routine Total Coliform Rule (TCR) (40 CFR 141.21) sample. These
   triggered source samples must be collected from ground water sources in use at the
   time of the TC positive. Samples must be collected within 24 hours unless the State
   allows an extension and the State will specify how long the extension is. Samples must
   be analyzed for the presence of one of three fecal indicators, E. coli, enterococci, or
   coliphage. See Ground Water Rule Triggered and Representative Monitoring: A Quick
   Reference Guide (EPA815-F-08-004) for more information.
   If a fecal indicator is found to be present in a triggered source sample and the State
   does not require corrective action, the GWR requires systems  to collect five additional
   source water samples and analyze  the samples for the presence of one of the three
   fecal indicators.
   Assessment source water monitoring may be required by the State for systems
   with sources that may be  at risk for fecal contamination. Systems must meet
   State requirements for the number of samples collected and the analyses (. coli,
   enterococci, coliphage) conducted.
                           Sampling Location
                           > For both triggered source water monitoring and assessment source water monitoring,
                              samples must be collected at the ground water source before treatment, unless
                              another location is approved by the State.
                           > GWSs should install a sample tap at each source to enable source water monitoring.
                           > The diagram below represents an appropriate sampling location for source water
                                       Pumps, Pump Facilities,
                                           and Controls
                                                                  SAMPLING LOCATION

Sample Collection
Sample Containers
^- Samples should be collected in sterile, plastic or glass containers with a leak-proof lid.
> The GWR requires GWSs conducting source water monitoring to analyze at least a 100-mL sample volume.
     However, EPA recommends that the GWS collect and ship more than 100-mL of sample to ensure that a minimum
      of 100 ml is available for analysis (see below).
> The sample containers should be large enough to allow at least 1-inch of headspace to facilitate mixing of the sample
   by shaking prior to analysis.
> Sample volume and container size recommendations for samples of various types are provided below.
. co// and
> Sample volume: At least 120 ml_ of sample should be collected to ensure sufficient volume for
   sample analysis is available in the event of spillage at the laboratory.
> Container Size: The capacity of sample containers should allow at least a 1-inch headspace to
   facilitate mixing of the sample by shaking prior to analysis.
^- Sample volume: If Method 1601 is used for coliphage sample analyses, either 100-mL or 1-L sample
   volumes may be analyzed (Method 1602 only accommodates 100-mL volumes).
    While the minimum sample volume requirement for the GWR is 100 mL, systems may wish to
     collect and analyze a 1-L sample volume to increase the sensitivity of the Method 1601 analysis.
    For all coliphage analyses, the GWS should collect 2.5 times more of the sample than necessary
     (i.e., 250 mL for 100 mL samples and 2.5 L for 1 L samples) to allow for sample re-analysis, if
> Container size: The capacity of sample containers should allow at least a 1 -inch headspace to
   facilitate mixing of the sample by shaking prior to analysis.
* Alternatively, samples for male-specific and somatic coliphage analyses can be collected in separate containers.
Collection  Procedures
Gloves and
hand washing
   When collecting samples from a ground water source, individuals should wash their hands before
   collecting samples and if possible wear gloves (latex, etc.).
   All samples taken should be recorded in an on-site sample log book or on a sample collection
   form if it is to be sent to a laboratory for analysis.  Sample log books and sample collection forms
   should contain the following information:
    Name of system (e.g., Public Water System Identification number)
    Sample site location
    Sample type (assessment, triggered)
    Sampler's name
    Sample number
    Date of sample collection
    Time of sample collection
    Analysis requested
Water tap and
service line
   Water taps used for sampling should be free of aerators, bubblers, strainers, hose attachments,
   mixing type faucets, and purification devices. The flow of water out of the tap should be adjusted so
   the water will not splash out when the sample is collected. The tap should be cleaned and flushed.
   The service line should be cleared before sampling by maintaining a steady water flow for at least
   two  minutes (or until the water changes temperature).
   Using aseptic technique (i.e., sanitize tap, do not touch the inside of the sample container), the
   individual taking the sample should fill the sample containers, leaving at least 1-inch of headspace.
Cap and label
the container
   Immediately following sample collection, the sampler should tighten the sample container lid.
   The system name, sampler's name, sample number, sample type, date and time of sample collection,
   sample location, and analysis requested should be recorded on the sample container.
   IMPORTANT: If the sample will not be shipped off-site for analysis immediately, the sample should be
   placed upright in a refrigerator to maintain the sample at a temperature of < 8C prior to shipment. If
   a refrigerator is unavailable, the sample should be insulated in some other manner to keep it cool.

 Sample Collection
 Sample Containers
   If the samples will be analyzed at a laboratory that is off-site, the water system should contact the
   laboratory as soon as possible (preferably prior to sampling) so that the laboratory can be prepared
   with the appropriate media.
   As soon as the sample has been collected, labeled and capped, the sample should be packaged in a
   shipping cooler or foam box that is used exclusively for this purpose.
     The cooler should be double lined with plastic (i.e., with trash bags) and contain ice (wet ice in
      ziplock bags,  gel packs, or blue ice).  The GWR  recommends keeping samples below 10C.
   The signed and dated sample collection form should be included with the sample.
   The lid of the cooler should be securely sealed and the joints of the container should  be sealed with
   duct tape.
   If the package is being  shipped, a copy of the airbill or shipping record should be kept by the ground
   water system.
   Packages should be sent priority overnight so that the arrangements for transport and shipping-time
   from collection to analysis does not exceed 30 hours as required by the GWR.
>  Sample collectors and laboratories should follow applicable State regulations pertaining to chain-of-
   custody procedures, since it is necessary to have an accurate written record to trace the possession
   and handling of samples from collection through reporting.
    This procedure includes:
         Field records of sample collection (sample collection form),
         Label or standardized tag on the sample container(s),
         Package sent to lab with chain-of-custody record form, pertinent field records, and analysis
         request form.
    The procedure used by the water system and the laboratory should be documented.
    Every person who takes custody of the sample should fill in the appropriate section of the chain-
     of-custody record.
    See EPA's Manual for the Certification of Laboratories Analyzing Drinking Water: Criteria and
     Procedures Quality Assurance (Fifth Edition) for more information.
Office of Water (4606)
July 2008