A \ LT2ESWTR Source Water Monitoring
xt&7 * systems Serving Less Than
3X
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. This factsheet
is for systems that serve less than 10,000 people. Note, if you sell water to a system that serves greater
than 10,000 people or are part of a combined distribution system and one of the consecutive systems
has a population greater than 10,000 people, please refer to the LT2ESWTR Source Water Monitoring
for Systems Serving At Least 10,000 People Factsheet (EPA 816-F-06-017).
WHAT Is THE PURPOSE OF SOURCE WATER MONITORING?
Source water monitoring data will be used to categorize the source water Cryptosporidium concentration in
to 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:
H Submit data from Cryptosporidium samples collected before the system must begin source water
monitoring 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.
WHAT ARE THE INITIAL SOURCE WATER MONITORING REQUIREMENTS?
The source water monitoring requirements of LT2ESWTR apply to all Subpart H PWSs. You are subject to
initial source water monitoring requirements if you do not have prior 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 at
www.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
Two options systems serving less than
10,000 people have to comply with the
source water monitoring requirements are:
• Conduct E. coli monitoring first and
based on those results, the system may
or may not need to conduct
Cryptosporidium monitoring, or
• Systems may go directly to
Cryptosporidium monitoring.
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 the date indicated in the schedule). In addition, you
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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 LESS THAN 10,000 PEOPLE - You should collect E. coli samples at least once
every 2 weeks for 12 months. You will then be required to monitor for Cryptosporidium at least twice per
month for 12 months, or at least once per month for 24 months, if either of the following conditions are
met:
• For systems using lakes or reservoirs, if the mean annual E. coli concentration is greater than 10
E. co/7/100 ml. This also applies to GWUDI systems if the nearest surface water body is a lake or
reservoir.
PI For systems using flowing stream sources, if the mean annual E. coli concentration is greater than 50
E. co/7/100 ml. This also applies to GWUDI systems if the nearest surface water body is a flowing
stream, or if there is no nearby surface water.
A system may choose to notify EPA or the state it will not collect the E. coli samples, but you will collect
Cryptosporidium samples at least twice per month for 12 months, or at least once per month for 24 months.
UNFILTERED SYSTEMS SERVING LESS THAN 10,000 PEOPLE - You must sample for Cryptosporidium at least
twice per month for 12 months, or at least once per month for 24 months.
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... < 10,000 and monitor < 10,000 and monitor for
for f . co/7 1 Cryptosporidium 2
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 A/lean Cryptosporidium
Level (Unfiltered)
Comply with additional LT2ESWTR treatment technique
requirements3
Must begin the second round of source water monitoring by...
July 1, 2008
October 2008
December 1 , 2008
October 1, 2017
January 1, 2010
April 2010
June 1, 2010
September 2012
October 1, 2014
April 1, 2019
1 Applies only to filtered systems.
2 Applies to filtered systems that exceed the E. coli trigger or do not monitor for E. coli and to unfiltered systems.
3 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 LESS THAN 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
Bin 3
Bin 4
... not required to monitor for Cryptosporidium
N/A
Bin 1
1 Samples must be analyzed by an approved laboratory and use EPA method 1622 or 1623.
2 Only for systems that do not exceed the E. coli trigger level.
ADDITIONAL TREATMENT REQUIREMENTS FOR FILTERED SYSTEMS - Additional treatment may be required
based on your bin classification. Refer to the table below for the additional Cryptosporidium treatment
requirements.
Bin
Classification
If the system uses the following filtration treatment in full compliance with existin"
requirements, th
IBJiH [i IM [•] IBll
Conventional filtration
treatment (including
softening)
Slow sand or Alternative
Direct filtration diatomaceous earth filtration
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 LESS THAN 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: Mean Cryptosporidium Cryptosporidium inactivation
Concentration1
Unfiltered
< 0.01 oocysts/L
> 0.01 oocysts/L
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 based
on 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. 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: 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 (Schedule 4)
n 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)
H 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)
• Small Entity Compliance Guidance (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-06-018 www.epa.gov/safewater June 2006
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