United States
Environmental Protection
Agency


Long  Term 2 Enhanced Surface Water
Treatment Rule: A Quick Reference
Guide  For Schedule  3 Systems
                       Title
                       Purposes
                       General
                       Description
                       Utilities
                       Covered
                                  Long Term 2 Enhanced Surface Water Treatment Rule (LT2ESWTR) 71 FR 654, January 5, 2006,
                                  Vol. 71, No. 3
           Improve public health protection through the control of microbial contaminants by focusing on
           systems with elevated Cryptosporidium risk. Prevent significant increases in microbial risk that
           might otherwise occur when systems implement the Stage 2 Disinfectants and Disinfection
           Byproducts Rule (Stage 2 DBPR).
           The LT2ESWTR requires systems to monitor their source water, calculate an average
           Cryptosporidium concentration, and use those results to determine if their source is vulnerable to
           contamination and may require additional treatment.
             Public water systems (PWSs) that use surface water or ground water under the direct influence
             of surface water (GWUDI).
             Schedule 3 systems include PWSs serving 10,000 to 49,999 people OR wholesale PWSs that are
             part of a combined distribution system in which the largest system serves 10,000 to 49,999
             people.
                       Major  Prov i si on
                       Control of Cryptosporidium
                       Source Water
                       Monitoring
                       Installation of
                       Additional
                       Treatment
                       Uncovered
                       Finished Water
                       Storage Facility
                Filtered and unfiltered systems must conduct 24 months of source water monitoring for
                Cryptosporidium. Filtered systems must also record source water E. coli and turbidity levels.
                Filtered systems will be classified into one of four "Bins" based on the results of their source
                water monitoring. Unfiltered systems will calculate a mean Cryptosporidium level to
                determine treatment requirements. Systems may also use previously collected data (i.e.,
                Grandfathered data).
                Filtered systems providing at least 5.5 log of treatment for Cryptosporidium and unfiltered
                systems providing at least 3-log of treatment for Cryptosporidium and those systems that
                intend to install this level of treatment are not required to conduct source water monitoring.
                Filtered systems must provide additional treatment for Cryptosporidium based on their bin
                classification (average source water Cryptosporidium concentration), using treatment
                options from the "microbial toolbox."
                Unfiltered systems must provide additional treatment for Cryptosporidium using chlorine
                dioxide, ozone, or UV.
                Systems with an uncovered finished water storage facility must either:
                > Cover the uncovered finished water storage facility; or,
                > Treat the discharge to achieve inactivation and/or removal of at least 4-log for viruses,
                  3-log for Giardia lamblia, and 2-log for Cryptosporidium.
                       Disinfection  Profiling and  Benchmarking
                       After completing the initial round of source water monitoring any system that plans on making a significant
                       change to their disinfection practices must:
                       > Create disinfection profiles for Giardia lamblia and viruses;
                         Calculate a disinfection benchmark; and,
                         Consult with the state prior to making a significant change in disinfection practice.
                        Cryp tosp oridium
                         Concentration
                           (oocysts/L)
                       < 0.075
                       0.075 to < 1.0
                       1.0to<3.0
                       >3.0
                        Bin
                   Classification
                                          Bin 1
                                          Bin 2
                                          Bin3
                                          Bin 4
                                                          Additional Cryptosporidium Treatment
                                                                         Required
                                  Conventional
                                    Filtration
                                                          No additional
                                                            treatment
                                                            required
                                                              1 log
                                                              2 log
                                                             2.5 log
 Direct
Filtration
                                                 No additional
                                                  treatment
                                                   required
                                                   1.5 log
                                                   2.5 log
                                                    Slog
 Slow Sand or
Diatomaceous
Earth Filtration
              No additional
           treatment required
                 1 log
                 2 log
                2.5 log
                           Alternative
                             Filtration
                 No additional
                  treatment
                   required
                     (1)
                     (2)
                     (3)
                       (1) As determined by the state (or other primacy agency) such that the total removal/inactivation > 4.0-log.
                       (2) As determined by the state (or other primacy agency) such that the total removal/inactivation > 5.0-log.
                       (3) As determined by the state (or other primacy agency) such that the total removal/inactivation > 5.5-log.

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  For additional information
  on the LT2ESWTR

  Call the Safe Drinking Water
  Hotline at 1-800-426-4791;
  visit the EPA website at
  www.epa.gov/safewater/
  disinfection/lt2; or contact
  yourstate drinking water
  representative.
Inactivation Requirements for Unfiltered Systems
Cryptosporidium Concentration Required Cryptosporidium
(oocysts/L) Inactivation
< 0.01 2-log
> 0.01 3-log

Critical Deadlines and Requirements
For Drinking Water Systems (Schedule 3)
January 1, 2008
April 2008
April 1, 2008
June 10, 2008
June 1, 2008
April 1, 2009
March 2010
September 2010
September 2010
September 30, 2013
July 1, 2016
Ocotber 1, 2016
Systems must submit their:
> Sampling schedule that specifies the dates of sample collection and location of
sampling for initial source water monitoring to EPAelectronically; or
> Notice to EPA or the state of the system's intent to submit results for grandfathering
data; or
> Notice to EPA or the state of the system's intent to provide at least 5.5-log of treatment
for Cryptosporidium for filtered systems or 3-log of treatment for unfiltered systems.
Systems should consult with EPAor their state prior to submitting this notice.
No later than this month, systems must begin 24 months of source water monitoring.
No later than this date, systems must notify the EPAor the state of all uncovered treated
water storage facilities.
Systems submit results for first month of source water monitoring.
No later than this date, systems must submit monitoring results for data that they want to
have grandfathered.
No later than this date, uncovered finished water storage facilities must be covered, or the
water must be treated before entry into the distribution system, or the system must be in
compliance with a state approved schedule.
No later than this month, systems must complete their inital round of source water
monitoring.
No later than this month, filtered systems must report their initial bin classification to the
EPAor the state for approval.
No later than this month, unfiltered systems must report the mean of all Cryptosporidium
sample results to the EPAor the state.
Systems must install and operate additional treatment in accordance with their bin
classification (filtered systems) or mean Cryptosporidium level (unfiltered systems). t
Systems must submit their sampling schedule that specifies the dates of sample collection
and location of sampling for second round of source water monitoring to the state.
> Systems are required to begin conducting a second round of source water monitoring.
> Based on the results, systems must re-determine their bin classification (filtered
systems) or mean Cryptosporidium level (unfiltered systems) and provide additional
Cryptosporidium treatment, if necessary.
For States
July - December
2006
April 1, 2007
October 5, 2007
January 5, 2008
December 31, 2009
January 5, 2010
June 30, 2014
States are encouraged to communicate with affected systems regarding LT2ESWTR
requirements.
States are encouraged to communicate LT2ESWTR requirements related to treatment,
uncovered finished water reservoirs, and disinfection profiling to affected systems.
States are encouraged to submit final primacy applications or extension requests to EPA.
Final primacy applications must be submitted to EPA, unless granted an extension.
States should begin determining Cryptosporidium treatment credit for primary treatments
already in place.
Final primacy revision applications from states with approved 2-year extensions
agreements must be submitted to EPA.
States should award Cryptosporidium treatment credit for toolbox option implementation.
                                   t States may allow up to an additional 24 months for compliance for systems making capital improvements.
Office of Water (4606)
EPA816-F-06-007
www.epa.gov/safewater
June 2006

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