&EPA
United States
Environmental Protection
Agency
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Ground Water Rule:
A Quick Reference
Overview of the Rul
Title
Purpose
General
Description
Utilities
Covered
Ground Water Rule (GWR) 71 FR 65574, Novembers, 2006, Vol. 71, No. 216
Correction 71 FR 67427, November 21, 2006, Vol. 71, No. 224
Reduce the risk of illness caused by microbial contamination in public ground water systems (GWSs).
The GWR establishes a risk-targeted approach to identify GWSs susceptible to fecal contamination
and requires corrective action to correct significant deficiencies and source water fecal contamination
in all public GWSs.
The GWR applies to all public water systems (PWSs) that use ground water, including consecutive
systems, except that it does not apply to PWSs that combine all of their ground water with surface
water or with ground water under the direct influence of surface water prior to treatment.
Public Health Benefits
Implementation
of the GWR will
result in . .
Estimated
impacts of
the GWR
include . .
Targeted protection for over 70 million people served by ground water sources that are either
not disinfected or receive less than 4-log treatment.
Avoidance of 42,000 viral illnesses and 1 related death annually.
The annualized present value of the GWR is $19.7 million, with a 90-percent confidence
interval of $6.5 to $45.4 million.
Mean annual cost per household is estimated to be less than $1.00 for approximately 96
percent of affected households.
Critical Deadlines and Requirements
For Drinking Water Systems
November 30, 2009
December 1 , 2009
December 1 , 2009
December 1 , 2009
New ground water sources put in place after this date must meet triggered source water
monitoring requirements or conduct compliance monitoring.
By this date, GWSs conducting compliance monitoring because they provide at least 4-log
virus inactivation, removal, or a state-approved combination of these technologies before or
at the first customer, must have notified the state and must begin compliance monitoring. The
written notification to the state must include engineering, operational, and other information
the state requests.
GWSs must conduct triggered source water monitoring if the GWS does not provide at least
4-log virus inactivation, removal, or a state-approved combination of these technologies
before or at the first customer and the GWS is notified that a sample collected for the Total
Coliform Rule (TCR) is total coliform-positive.
GWSs for which the state has identified a significant deficiency and GWSs at which at least
one of the five additional ground water source samples (or at state discretion, after the initial
source sample) has tested positive for fecal contamination must comply with the treatment
technique requirements.
For States
August 8, 2008
Novembers, 2008
Augusts, 2010
Novembers, 2010
December 31, 2012
December 31, 2014
States are encouraged to submit final primacy applications or extension requests to EPA.
Final primacy revision applications for GWR must be submitted to the EPA regional
administrator, unless state is granted an extension.
States with approved extension agreements are encouraged to submit final primacy
applications to EPA.
Final primacy applications must be submitted to the EPA regional administrator for states with
a full 2 year extension.
States must complete initial sanitary survey cycle for all community GWSs except those that
meet performance criteria.
States must complete initial sanitary survey cycle for all noncommunity GWSs and all
community GWSs that meet performance criteria.
Analytical Methods for Source Water Monitoring
Fecal Indicator
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Enterococci
Coliphage
Methodology
Colilert
Colisure
Membrane Filter Method with Ml Agar
m-ColiBlue24 Test
E*Colite Test
EC-MUG
NA-MUG
Multiple-Tube Technique
Membrane Filter Technique
Membrane Filter Technique
Enterolert
Two-Step Enrichment Presence-Absence Procedure
Single Agar Layer Procedure
Method Citation*
9223 B.
9223 B.
EPA Method 1604.
9221 F.
9222 G.
9230 B.
9230 C
EPA Method 1600.
EPA Method 1601.
EPA Method 1602.
*Footnotes regarding methods can be found in 40 CFR 141.402
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For additional information
on the GWR
Call the Safe Drinking
Water Hotline at
1-800-426-4791; visit the
EPA web site at www.
epa.gov/safewater/
disinfection/gwr; or contact
your state drinking water
representative.
Major Provisions
Compliance Monitoring
Treatment
Technique
Compliance
Monitoring
In order not to be subject to triggered source water monitoring, a GWS can notify the
state that it provides at least 4-log treatment of viruses using virus inactivation, removal,
or a state-approved combination of 4-log virus inactivation and removal before or at the
first customer. The GWS must then begin compliance monitoring designed to show the
effectiveness of their treatment processes.
GWSs that use chemical disinfection and serve more than 3,300 people must continuously
monitor their disinfectant concentration. GWSs must maintain the minimum disinfectant
residual concentration determined by the state.
GWSs that use chemical disinfection and serve 3,300 people or fewer must take daily
grab samples or meet the continuous monitoring requirements described above for GWSs
serving more than 3,300 people.
GWSs using membrane filtration for 4-log treatment of viruses must monitor the membrane
filtration process according to state-specified monitoring requirements.
GWSs may use alternative treatment technologies (e.g., ultraviolet radiation [UV])
approved by the state. GWSs must monitor the alternative treatment according to state-
specified monitoring requirements, and must operate the alternative treatment according to
compliance requirements established by the state.
Source Water Monitoring
Triggered Source
Water Monitoring
Additional
Source Water
Sampling
Assessment
Source Water
Monitoring
GWSs that do not conduct compliance monitoring and are notified of a total coliform-positive
routine sample collected in compliance with the TCR (40 CFR 141.21) must conduct
triggered source water monitoring.
GWSs must collect at least one ground water source sample from each source in use at the
time the total coliform-positive sample was collected. The triggered source water sample
must be analyzed for the presence of a fecal indicator as specified in the rule.
If the triggered source water sample is fecal indicator-positive, the GWS must either take
corrective action, as directed by the state, or if corrective action is not required by the state
and the sample is not invalided by the state, the GWS must conduct additional source water
sampling.
States may waive the triggered source water monitoring requirement if the state determines
and documents, in writing, that the total coliform-positive routine sample is the result of a
documented distribution system deficiency.
States may develop criteria for distribution system conditions that cause total coliform
positive samples. A GWS can document to the state that it met the state criteria within 30
days of the total coliform-positive sample and be exempt from collecting triggered source
water sample(s).
States may invalidate a fecal indicator-positive ground water source sample under specific
conditions. If a fecal indicator-positive source sample is invalidated, the GWS must collect
another source water sample within 24 hours of being notified by the state of its invalidation
decision.
If the state does not require corrective action in response to a fecal indicator-positive
triggered source water sample, the GWS must collect five additional source water samples
(from the same source), using the same indicator as used in triggered source water
monitoring, within 24 hours of being notified of the fecal indicator-positive sample.
States have the opportunity to target higher risk GWSs for additional testing. States
independently can determine on a case by case basis whether monitoring is necessary and
when corrective action needs to be taken.
Treatment Technique Requirements
GWSs with
Significant
Deficiencies
or Source
Water Fecal
Contamination
GWSs must take corrective action if a significant deficiency is identified, or if the initial
source sample (if required by the state) or one of the five additional ground water source
samples tests positive for fecal contamination. The GWS must implement at least one of the
following corrective actions:
> Correct all significant deficiencies.
^ Provide an alternate source of water.
^ Eliminate the source of contamination.
^ Provide treatment that reliably achieves at least 4-log treatment of viruses (using
inactivation, removal, or a state-approved combination of 4-log virus inactivation and
removal) before or at the first customer for the ground water source.
New Sources
New Ground
Water Sources
New sources which come on line after November 30, 2009 are required either to conduct
triggered source water monitoring as required by the GWR, or provide at least 4-log
inactivation, removal or a state-approved combination of these technologies and conduct
compliance monitoring within 30 days of the source being put in service.
Sanitary Surveys
All Ground Water
Systems
States are required to conduct sanitary surveys of all GWSs in order to identify significant
deficiencies, including deficiencies which may make a system susceptible to microbial
contamination.
Following the initial sanitary survey, states must conduct sanitary surveys every 3 years for
most CWSs and every 5 years for NCWSs and CWSs that provide at least 4-log treatment
of viruses or have outstanding performance records, as determined by the state.
iter (4606M)
EPA-816-F-08-029
www.epa.gov/safewater
June 2008
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