UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
                                                                               WSG 16
                                                              Date Signed: June 20, 1979
MEMORANDUM

SUBJECT:   Guidance for Operation and Maintenance (O&M) Plans for ICCs

FROM:      James F. Manwaring, Chief (signed by James Manwaring)
             Drinking Water Branch (WH-550)

TO:          Regional Water Supply Representatives, I-X
       This memo should be considered as guidance for evaluating the Operation and
Maintenance (O&M) plans as a replacement for the quarterly bacteriological analysis. The
following has been developed from our discussions with the Interstate Carrier Conveyance (ICC)
industry and is presented for your reference.

       An acceptable practice for flushing and disinfecting the drinking water systems on-board
the conveyance has been described as follows:

       (1)     Open all taps and completely drain water from the conveyance water tanks.

       (2)     A chlorine solution is fed into the conveyance water system until 100 ppm of total
              residual is read at all taps.

       (3)     The above system is allowed to stand at least an hour and then is drained through
              all taps until completely empty.

       (4)     The system is then refilled with drinking water from an approved source and
              allowed to overflow for two minutes.

       Since the O&M program is an option to be exercised in lieu of the requirement for
quarterly microbiological monitoring, the flush and disinfection procedures for on-board systems
shall be applied at least twice annually. The water service vehicles which are used to load
drinking water on the conveyance shall be included in the O&M program. Such vehicles shall be
flushed and disinfected at least once a month. In the event that this O&M procedure causes a
significant adverse effect on the conveyance operator resources, the EPA Regional Offices may
modify this requirement. It is the responsibility of the conveyance operator to demonstrate that
modification of O&M procedures will not adversely affect the quality of drinking water on-
board. The records associated with the O&M procedures shall be maintained by the conveyance
operator for five years. This determination is predicated on the National Interim Primary
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                                                                                 WSG16

Drinking Water Regulations Section 141.33 - Record Maintenance.

       The aforementioned example of an acceptable flush and disinfection procedure is not the
only procedure that should be considered acceptable. All procedures submitted by conveyance
operators, including alternate disinfectants, should be considered on an individual basis. The
conveyance operator shall be responsible for providing proof of the adequacy of his plan,
including information on the toxicity of alternate disinfectants to humans. Recommendations on
the acceptability of such disinfections shall be provided by EPA, ODW Headquarters, upon
request from the Region. If the conveyance on-board drinking water system or water service
vehicle water system is in any way serviced or repaired, the system shall be flushed and
disinfected prior being returned to service.

       The documentation describing the O&M plan which is submitted by the conveyance
operator should contain the following:

       (1)    A cover letter which includes a summary of the water handling procedures and
             O&M program documentation. Included in the summary should be estimated time
             interval for service of conveyance drinking water system;  a brief description of the
             disinfection procedures; and a description of intended annual report data.

       (2)    Actual detailed documentation of the disinfection procedures (i.e. excerpts from
             maintenance manuals and examples of maintenance inspection forms).

       (3)    Procedure for on-board water treatment. If carbon filters are  employed on
             conveyance, a description of operating procedures is required.  The description
             should indicate filter capacity, estimated flow rate, service interval, chlorine
             residual of water used to charge on-board system and whether water is chlorinated
             by operator.

       The approval of the O&M plans shall have a term of one year, initially. At such time
when program experience demonstrates, the approval period may be altered.

       It is important that ICC operators which choose the O&M option, have their plans
approved within three months of the June 24, implementation date. The conveyance operators
which do not have approved plans by September 24, will be required to perform a quarterly
bacteriological analysis of all their conveyances, or be in violation of the regulations.

       Approval of the O&M plans is the responsibility of the Regions. Assistance from
Headquarters is available on request. Any significant deviation from the O&M requirements of
this guidance should be discussed with Headquarters prior to approval by Regions. The
Headquarters concurrence stipulated in Water Supply 56A, can be  handled via telephone
communication.
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                                                                         WSG16

*May possibly be updated. Contact Steve Clark at Headquarters for further information
regarding ICC Guidances.

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