J.
A \ LT2ESWTR Source Water Monitoring
for Systems Serving At Least 10,000
People Factsheet
WHAT Is THE LT2ESWTR?
The U.S. Environmental Protection Agency (EPA) published the Long Term 2 Enhanced Surface Water
Treatment Rule (LT2ESWTR) on January 5, 2006. The LT2ESWTR improves control of microbial
pathogens. The LT2ESWTR requires source water monitoring at public water systems (PWSs) that use
surface water or ground water under the direct influence of surface water (GWUDI) (i.e., Subpart H
PWSs). Based on system size and filtration type, systems need to monitor for Cryptosporidium, E. coli,
and turbidity.
WHAT Is THE PURPOSE OF SOURCE WATER MONITORING?
Source water monitoring data will be used to categorize the source water Cryptosporidium
concentration into one of four "bin" classifications that have associated treatment requirements. The
LT2ESWTR provides other options for systems to comply with the initial source water monitoring
requirements:
PI Submit data from Cryptosporidium samples collected before the system must begin source water
monitoring (i.e., Grandfathered), and the data must meets certain requirements.
• Filtered systems may skip source water monitoring and commit to provide a total of at least 5.5-
log of treatment for Cryptosporidium, equivalent to meeting the treatment requirement of Bin 4.
Unfiltered systems skip source water monitoring and commit to provide a total of at least 3-log
Cryptosporidium inactivation, which is equal to meeting the treatment requirements for
unfiltered systems with a mean Cryptosporidium concentration of greater than 0.01 oocysts/L.
Systems that decide to skip monitoring and provide maximum treatment must notify the state in
writing.
A second round of source water monitoring will follow 6 years after the system makes its initial bin
determination. Grandfathering is not available for the second round of source water monitoring.
Note: E. coli and turbidity data may not be grandfathered unless the system is also grandfathering
corresponding Cryptosporidium data.
WHAT ARE THE INITIAL SOURCE WATER MONITORING REQUIREMENTS? _
The source water monitoring requirements of the LT2ESWTR apply to all Subpart H PWSs. You are
subject to initial source water monitoring requirements if you do not have existing monitoring data
that meets grandfathering requirements. For more information on source water monitoring
requirements, see EPA's Source Water Monitoring Guidance Manual for Public Water Systems for the
Final Long Term 2 Enhanced Surface Water Treatment Rule (EPA 815-R06-005 February 2006),
available atwww.epa.gov/safewater/disinfection/lt2/compliance.html.
Prior to beginning initial source water monitoring, you must submit a sampling schedule that specifies
the calendar dates when you will collect the required source water samples. The samples must be
evenly spaced throughout the monitoring period (e.g., monthly on the 15th of each month). However,
the schedule may be altered to take into account holidays, weekends, or other events. All the samples
must be taken within a 5-day window (i.e., you can take the sample up to 2 days before or 2 days after
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the date indicated in the schedule). In addition, you must submit a description of the intended
sampling location in relation to the source and any treatment processes, as well as a description of any
points of chemical addition, and filter backwash recycle.
• FILTERED SYSTEMS SERVING AT LEAST 10,000 PEOPLE - You must collect Cryptosporidium,
E. coll and turbidity samples at least monthly for 24 months.
• UNFILTERED SYSTEMS SERVING AT LEAST 10,000 PEOPLE - You must sample for Cryptosporidium
at least monthly for 24 months.
Alternately, you may notify the EPA or the state that you elect not to conduct source water monitoring
and commit to providing the maximum treatment of 5.5 log removal or inactivation for filtered
systems or 3-log inactivation for unfiltered systems.
WHEN MUST I COMPLY WITH THE MONITORING REQUIREMENTS?
The system compliance schedule is based on the population served by your system. A PWS must
conduct monitoring based on the requirements of the largest system in the combined distribution
system. The interconnected wholesale/consecutive systems relationships have been determined by
the state.
Systems that serve...
Submit: Sample Schedule and Sample
Location Description
Must begin the first round of source
water monitoring by...
Submit Grandfathered Data (if
applicable)
Submit Bin Classification (Filtered) or
Mean Cryptosporidium Level
(Unfiltered)
Comply with additional LT2ESWTR
treatment technique requirements2
Must begin the second round of source
water monitoring by...
> 100,000 people
(Schedule 1)1
July 1, 2006
October 2006
December 1 , 2006
March 2009
April! , 2012
April 201 5
50,000 to 99,999
people
(Schedule 2) 1
January 1 , 2007
April 2007
June 1, 2007
September 2009
October 1, 2012
October 201 5
10,000 to 49,999
people
(Schedule 3) 1
January 1, 2008
April 2008
June 1 , 2008
September 2010
October 1, 2013
October 201 6
1 Your schedule is defined by the largest system in your combined distribution system.
2 State may allow up to an additional 2 years for capital improvements to comply with the treatment technique.
WHAT Is A BIN CLASSIFICATION?
FILTERED SYSTEMS SERVING AT LEAST 10,000 PEOPLE - You will be classified into a "bin" based on
the results of your source water monitoring. Your bin classification determines whether further
treatment for Cryptosporidium is required. A second round of source water monitoring is required 6
years after your initial bin classification and may affect your bin classification.
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For systems that are:
.required to monitor for Cryptosporidium
Mean Cryptosporidium
Concentration1
< 0.075 oocysts/L
from 0.075 to < 1.0 oocysts/L
from 1.0 to < 3.0 oocysts/L
^3.0 oocysts/L
Bin Classification
Bin 1
Bin 2
Bin3
Bin 4
1 Samples must be analyzed by an approved laboratory and use EPA method 1622 or 1623.
ADDITIONAL TREATMENT REQUIREMENTS FOR FILTERED SYSTEMS - Additional treatment is required
if the bin classification is a 2, 3, or 4. Refer to the table below for the additional Cryptosporidium
treatment requirements.
Classification
If the system uses the following filtration treatment in full compliance with existin
requirements, thi
Conventional filtration
treatment (including
softenini
Direct filtration
Slow sand or
diatomaceous
earth filtration
Alternative
filtration
technologies
Bin 1
Bin 2
Bin 3
Bin 4
No additional treatment
1-log treatment
2-log treatment
2.5-log treatment
No additional
treatment
1.5-log treatment
2.5-log treatment
3-log treatment
No additional
treatment
1-log treatment
2-log treatment
2.5-log treatment
No additional
treatment
(1)
(2)
(3)
(1) As determined by the state such that the total Cryptosporidium removal and inactivation is at least 4.0-log.
(2) As determined by the state such that the total Cryptosporidium removal and inactivation is at least 5.0-log.
(3) As determined by the state such that the total Cryptosporidium removal and inactivation is at least 5.5-log.
For information on the toolbox options that can be used to achieve additional log removal
requirements, see the Long Term 2 Enhanced Surface Water Treatment Rule Toolbox Guidance Manual
(draft version anticipated late 2006).
UNFILTERED SYSTEMS SERVING AT LEAST 10,000 PEOPLE - You must calculate an arithmetic mean of
all Cryptosporidium samples concentrations required. Following completion of the second round of
source water monitoring, you must provide a level of inactivation for Cryptosporidium based on the
arithmetic mean of your Cryptosporidium sample concentrations.
For systems that are:
Unfiltered
Mean Cryptosporidium
Concentration1
< 0.01 oocysts/L
0.01 oocysts/L
Cryptosporidium inactivation
2-log
3-log
1 Samples must be analyzed by an approved laboratory and use EPA method 1622 or 1623.
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ARE You CONSIDERING MAKING A CHANGE To YOUR DISINFECTION PRACTICES?
After completing the initial round of source water monitoring, systems that plan to make a significant
change to their disinfection practice must notify the state, develop disinfection profiles, and calculate
disinfection benchmarks for Giardia lamblia and viruses. To develop a profile and benchmark, PWSs
must monitor at least weekly for a period of 12 consecutive months to determine the total log
inactivation for Giardia lamblia and viruses. The disinfection benchmark is an indicator of disinfection
effectiveness and depends upon the inactivation of Giardia lamblia or viruses. The benchmark is
determined by calculating the average daily inactivation value for each of 12 consecutive months. The
lowest monthly average becomes the disinfection benchmark. If the PWS has data from more than 1
year, the benchmark is the average of the lowest monthly average value for each of the years. A PWS
may use grandfathered data that is substantially equivalent to develop the disinfection profiles for
Giardia lamblia and viruses. The Long Term 1 Enhanced Surface Water Treatment Rule (LT1ESWTR)
Disinfection Profiling and Benchmarking Technical Guidance Manual (EPA 816-R-03-004, May 2003),
provides guidance for developing a disinfection profile and benchmark. EPA has developed two tools
for systems to determine their disinfection profile and calculate the benchmark at the following
website: http://www.epa.gov/safewater/mdbp/lt1eswtr.html.
ADDITIONAL GUIDANCE MATERIALS
The following guidance document addresses the source water monitoring requirements for the
LT2ESWTR:
• Source Water Monitoring Guidance Manual for Public Water Systems for the Final Long Term 2
Enhanced Surface Water Treatment Rule (EPA 815-R06-005 February 2006) - Provides surface
water systems, laboratories, states, and Tribes with a review of the source water monitoring
provisions. The source water monitoring guidance manual provides direction to the systems on
how, where and when to monitor, how to report the data, how to submit "grandfathered" data
(e.g., previously collected data), and how the data can be evaluated and used to determine risk
bin classification.
For additional guidance on implementing the LT2ESWTR, you may refer to the following existing and
future EPA materials:
• LT2ESWTR Quick Reference Guides (Schedules 1 - 3)
PI On-line Microscopy Training Module
• On-line Sample Collection Module
• Microbial Laboratory Guidance Manual for the Final Long Term 2 Enhanced Surface Water
Treatment Rule (EPA 815-R06-006 February 2006)
PI Membrane Filtration Guidance Manual (EPA 815-R-06-009 November 2005)
• Membrane Filtration Guidance Manual: Overview and Summary Factsheet
(www.epa.gov/safewater/disinfection/lt2/pdfs/guide It2 membranefiltration fs final.pdf)
• Ultraviolet Disinfection Guidance Manual and Workbook (final version anticipated mid-2006)
• Simultaneous Compliance Guidance Manual for Stage 2 Rules (draft version anticipated mid-2006)
• Long Term 2 Enhanced Surface Water Treatment Rule Toolbox Guidance Manual (draft version
anticipated late 2006)
For additional information, please contact the Safe Drinking Water Hotline at 1-800-426-4791,
send an email to stage2mdbp@epa.gov, or visit www.epa.gov/safewater/disinfection/lt2.
Office of Water (4606) EPA 816-F-06-017 www.epa.gov/safewater/d1s1nfect1on/lt2 June 2006
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