UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
                       GUIDANCE FROM HOTLINE COMPENDIUM
                                                                                WSGH53
                                                                Date Issued: December 1999

SUBJECT:    Point-of-Entry (POE) Devices to Comply with the Total Coliform Rule, Surface Water
              Treatment Rule (SWTR) and Interim Enhanced Surface Water Treatment Rule
              (IESWTR)

SOURCE:     Clive Davies, OGWDW
              (202)260-1421

       The Total Coliform Rule, SWTR, and IESWTR apply to public water systems; i.e., systems
serving at least 15 service connections or 25 people per day.  Individual households may use POE
devices at their own discretion and have no requirements to meet the Safe Drinking Water Act.
Though generally not recommended, POE devices may in some circumstances be used in lieu of
centralized treatment to comply with the Total Coliform Rule, SWTR, or IESWTR, or as a condition
for obtaining an exemption.  Exemptions are time delays for meeting the criteria of a National Primary
Drinking Water Regulation (NPDWR). Exemptions may be granted by the State depending upon the
circumstances of a system. Exemptions for systems with 500 or fewer service connections can be
renewed indefinitely if applicable criteria are met.

       Section 141.100,  Subpart J of the NPDWR (enclosed) specifies conditions which must be met
for POE devices to be used to comply with a Maximum Contaminant Level (MCL) such as the Total
Coliform Rule. Though not stated in Section 141.100, these conditions are also appropriate for
determining if POE devices may be used for complying with a treatment technique requirement such as
the SWTR and IESWTR. In addition, the SWTR and IESWTR require that alternative filtration
technologies such as POE devices, in accordance with Section 1412 (b)(4)(E), must be "owned,
controlled, and maintained" by the PWS and cannot use POU devices for microbial control. These
devices must also be demonstrated to the satisfaction of the State that, in combination with disinfection,
they are capable of achieving at least 99.9 and 99.99 percent removal and/or inactivation of Giardia
cysts and viruses, respectively.  Also, for systems serving more than 10,000 people, the IESWTR
requires that POE devices achieve 99.0 percent removal of Cryptosporidium cysts. The characteristics
of the POE device and the maintenance program will determine the amount of monitoring which is
appropriate to ensure that adequate treatment is being provided on an ongoing basis.

      The SWTR and IESWTR allow for continuous turbidity monitoring with periodic validation in
lieu of grab sample monitoring. If continuous monitoring is used, measurements are to be read from a
recorder at four-hour intervals to determine compliance. For alternative filtration technologies (which
would include POE devices), the SWTR allows the State to reduce turbidity monitoring to one
representative sample of the filtered water per day,  depending upon the characteristics of the
technology. If the performance of one POE device cannot be relied on to reflect the performance of
the other POE devices, at least one sample per day from each device should be required. In some
cases it may be possible, depending upon the design of the POE device and the maintenance program
in place, that representative monitoring can be achieved with one sample from a different POE device

-------
each day.
       Regarding disinfection with ultraviolet light, the SWTR and IESWTR do not allow for this
technology to be used alone for providing disinfection.  Ultraviolet light is not known to be effective for
inactivating Giardia cysts and it does not provide a disinfectant residual. However, ultraviolet light is
effective for inactivating viruses in non-turbid waters.  It appears that a POE device which removes at
least 99.9 percent of Giardia cysts followed by disinfection with ultraviolet light, which achieves with
filtration at least 99.99 percent removal and inactivation of viruses, could be an effective means of
providing adequate treatment for individual households. EPA is considering use  of ultraviolet light in the
forthcoming disinfection requirements for ground water systems that EPA plans to propose in early
2000. Additionally, recent data indicate that ultraviolet light may be effective against Cryptosporidium.

-------