UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
                    GUIDANCE FROM HOTLINE COMPENDIUM
                                                                          WSGH35
                                                             Date Issued: August 1991


SUBJECT:    Reporting Confluent Growth on Total Coliform Samples

SOURCE:    Paul Berger
             (202) 260-3039
Title 40 CFR sections 141.21(g) and 141.32 contain requirements for analytical methodology and
reporting under the Total Coliform Rule.  Is confluent bacterial growth considered a violation of
the rule and how would it be reported?

       Response:

       If one or more total coliform colonies are detected, the sample must be reported as total
       coliform-positive.  If no coliforms are detected, the laboratory must invalidate the sample
       (see 40 CFR 141.21 (c) (2)).  The regulations do not specifically address how confluent
       growth (with no detected coliforms) is to be reported, but the laboratory may record the
       sample as "confluent growth."

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