&EPA
United States
Environmental Protection
Agency
Ground Water Rule (GWR) Monitoring Requirements
Consecutive Systems With Their Own Source Conducting Triggered Source Water Monitoring
See additional placards for requirements for systems with their own source that do not purchase water or sell water to another system, wholesale
systems, consecutive systems without their own source, and those providing 4-log treatment of viruses and conducting compliance monitoring
TOTAL COLIFORM-POSITIVE
You must conduct triggered source water monitoring at
each ground water well in response to a total coliform-
positive routine sample collected under the Total
Coliform Rule (TCR) unless you are conducting compliance
monitoring for 4-log treatment of viruses.
• Notify any wholesale systems from which you receive
water WITHIN 24 HOURS of receiving notice of a total
coliform-positive routine sample.
• Conduct triggered source water monitoring at each of
your own ground water well(s) WITHIN 24 HOURS1 of
being notified of a total coliform-positive routine sample.
• If you suspect the total coliform-positive routine sample
was caused by a distribution system problem, contact
your state to discuss options.
• Sample from each source in use at the time the total
coliform-positive routine sample was taken for every total
coliform-positive routine sample, unless the state has
approved representative monitoring.
- Your state may allow you to use representative source
water monitoring to reduce the number of samples
collected. Contact your state for approval.
• Sample for the state-approved fecal indicator. Contact
your state to determine which one(s) is approved and list
here:
1 Contact your state to ensure you are following the
correct sampling procedures and contact your lab to
ensure you are using the appropriate materials for
monitoring. If your system serves <1,000 people, you may
be able to use TCR repeat monitoring collected from a
ground water source to meet GWR requirements. Contact
your state for more information.
FECAL INDICATOR-POSITIVE
If triggered source water monitoring
results from your source are fecal
indicator-positive you must:
Notify your state and if your state
does not require corrective action,
collect 5 additional source water
samples WITHIN 24 HOURS.1
The state may invalidate a fecal
indicator-positive sample on a case-
by-case basis. Contact your state. If
your sample is invalidated, you must
resample for the same indicator
WITHIN 24 HOURS.1
Notify the public with a Tier 1 Public
Notice (PN) WITHIN 24 HOURS.
Community water systems must
notify the public with a Special
Notice in your next CCR.
If triggered source water monitoring
from your wholesale system's source is
fecal indicator-positive you must:
Notify the public with a Tier 1 PN
WITHIN 24 HOURS.
Community water systems must
notify the public with a Special
Notice in your next CCR.
Laboratory Contact Information:
ADDITIONAL MONITORING
If your fecal indicator source water
sample is positive then the state may
require additional monitoring:
Take 5 samples from each source that
was fecal indicator-positive WITHIN 24
HOURS.1
• If an additional sample is fecal-indicator
positive, you must:
- Notify the public with a Tier 1 PN
WITHIN 24 HOURS.
- Community water systems must notify
the public with a Special Notice in
your next CCR.
- Consult with your state and take
approved Corrective Action.
If you are notified by your wholesale
system that additional source water
monitoring results are fecal indicator-
positive you must:
• Notify the public with a Tier 1 PN
WITHIN 24 HOURS.
• Community water systems must notify
the public with a Special Notice in your
next CCR.
• Consult with your state and take
approved Corrective Action.
CORRECTIVE ACTION
You have to take corrective action if you are notified of
a fecal indicator-positive additional sample, a significant
deficiency, or if the state requires it in response to a fecal
indicator-positive triggered or assessment sample.
• A significant deficiency may be identified during a sanitary
survey or at any other time.
• You are required to provide the state with information
requested to complete a sanitary survey.
• Within 30 days of notification you must consult with your
state to determine a corrective action unless your state
specifies a corrective action.
• Corrective Action options are:
- Correct all significant deficiencies
- Provide an alternate source of water
- Eliminate the source of contamination
- Provide 4-log treatment of viruses.
• Within 120 days of notification you must complete
corrective action, or be in compliance with state-approved
corrective action plan and schedule.
• If you fail to take corrective action, you will incur a
treatment technique violation and must notify your state
within 48 hours and notify the public with a Tier 2 PN
within 30 days.
• Community water systems: If you have not corrected
the significant deficiency before the end of the calendar
year, you must notify the public with a Special Notice in
your next CCR and repeat annually until the significant
deficiency has been addressed.
• Noncommunity water systems: If you have not corrected
the significant deficiency within 12 months, you must
notify the public with a Special Notice and repeat annually
until the significant deficiency has been addressed.
Footnote 1: The state may provide more time on a case-by-case basis. Contact your state if you face circumstances beyond your control.
If you fail to conduct required monitoring within 24 hours of notification of a total coliform- or fecal indicator-positive sample, you must notify the public with a Tier 3 PN (possibly in your next CCR).
More information can be found in EPA's Consecutive Systems Guide for the GWR (EPA 815-R-07-020, July 2007).
The term "state" is used to refer to all types of primacy agencies including states, U.S. territories, Indian tribes, and EPA.
Wholesale Systems' Contact Information:
You are required to notify all wholesale systems WITHIN 24 HOURS of receiving notice of a total coliform-positive sample. Please ensure that all wholesale systems' contact information is available and
provided below to ensure that they can be contacted within the appropriate timeframe.
Name:
Phone Number:
Name:
Phone Number:
Name:
Phone Number:
Name:
Phone Number:
State/Primacy Agency Contact (name and phone number):.
Office of Water (4606M) EPA 816-F-10-056 www.epa.gov/safewater April 2010
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