United States
Environmental Protection
Agency
815RO6OO3
Final Ground Water Rule
Summary
The Environmental Protection Agency (EPA) promulgated the final Ground Water Rule (GWR) in
October 2006 to reduce the risk of exposure to fecal contamination that may be present in public water
systems that use ground water sources. EPA proposed the GWR on May 10, 2000 (65 Federal Register
30194). The rule establishes a risk-targeted strategy to identify ground water systems that are at high
risk for fecal contamination. The GWR also specifies when corrective action (which may include
disinfection) is required to protect consumers who receive water from ground water systems from
bacteria and viruses.
Background
The 1996 Amendments to the Safe Drinking Water Act required EPA to develop regulations that
require disinfection of ground water systems "as necessary" to protect the public health (section
Ground water occurrence studies and recent outbreak data show that pathogenic viruses and bacteria
can occur in public water systems that use ground water and that people may become ill due to
exposure to contaminated ground water.
Most cases of waterborne disease are characterized by gastrointestinal symptoms (e.g., diarrhea,
vomiting, etc.) that are frequently self-limiting in healthy individuals and rarely require medical
treatment. However, these same symptoms are much more serious and can be fatal for persons in
sensitive subpopulations (such as young children, the elderly, and persons with compromised immune
systems).
Viral and bacterial pathogens are present in human and animal feces, which can, in turn, contaminate
drinking water. Fecal contamination can reach ground water sources, including drinking water wells,
from failed septic systems, leaking sewer lines, and by passing through the soil and large cracks in the
ground. Fecal contamination from the surface may also get into a drinking water well along its casing or
through cracks if the well is not properly constructed, protected, or maintained.
EPA does not believe all ground water systems are fecally contaminated; data indicate that only a small
percentage of ground water systems are fecally contaminated. However, the severity of health impacts
and the number of people potentially exposed to microbial pathogens in ground water indicate that a
regulatory response is warranted.
About this Regulation
The GWR applies to more than 147, 000 public water systems that use ground water (as of 2003). The
rule also applies to any system that mixes surface and ground water if the ground water is added
directly to the distribution system and provided to consumers without treatment equivalent to surface
water treatment. In total, these systems provide drinking water to more than 100 million consumers.
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Final Requirements: The rule addresses risks through a risk-targeting approach that relies on four
major components:
1. Periodic sanitary surveys of ground water systems that require the evaluation of eight critical
elements and the identification of significant deficiencies (e.g., a well located near a leaking
septic system). States must complete the initial survey by December 31, 2012 for most
community water systems (CWSs) and by December 31, 2014 for CWSs with outstanding
performance and for all non-community water systems.
2. Source water monitoring to test for the presence of E. coli, enterococci, or coliphage in the
sample. There are two monitoring provisions:
-Triggered monitoring for systems that do not already provide treatment that achieves at
least 99.99 percent (4-log) inactivation or removal of viruses and that have a total coliform-
positive routine sample under Total Coliform Rule sampling in the distribution system.
-Assessment monitoring- As a complement to triggered monitoring, a State has the option
to require systems, at any time, to conduct source water assessment monitoring to help
identify high risk systems.
3. Corrective actions required for any system with a significant deficiency or source water fecal
contamination. The system must implement one or more of the following correction action
options:
-correct all significant deficiencies,
-eliminate the source of contamination,
-provide an alternate source of water, or
-provide treatment which reliably achieves 99.99 percent (4-log) inactivation or removal of
viruses. . .-
4. Compliance monitoring to ensure that treatment technology installed to treat drinking water
reliably achieves at least 99.99 percent (4-log) inactivation or removal of viruses.
Environmental and Public Health Benefits
The GWR will reduce public health risk from contaminated ground water drinking water sources,
especially in high-risk or high-priority systems. The GWR is estimated to reduce the average number
of waterborne viral (rotovirus and echovirus) illnesses by nearly 42,000 illnesses each year from the
current baseline estimate of approximately 185,000 (a 23 percent reduction in total illnesses). In
addition, nonquantified benefits from the rule resulting in illness reduction from other viruses and
bacteria are expected to be significant.
Cost of the Regulation
The GWR will result in increased costs to public water systems and States. The mean annualized
present value national compliance costs of the final GWR are estimated to be approximately $62
million (using three percent discount rate). Public water systems will bear the majority of costs. The
annual household costs for community water systems (including those that do not add treatment) range
from $0.21 to $16.54. Annual household costs for the subset of systems that undertake corrective
actions range from $0.45 to $52.38, with 90 percent having household cost increases of no more than
$3.20.
How to Get Additional Information
For general information on the GWR, please contact the Safe Drinking Water Hotline, at (800) 426-
4791. The Safe Drinking Water Hotline is open Monday through Friday, excluding Federal holidays,
from 10 a.m. to 4 p.m., Eastern time. For copies of the Federal Register notice of the final regulation,
visit the EPA Safewater Web site, http://www.epa.gov/safewater/disinfection/gwr.
Office of Water (4607M) EPA 815-F-06-003 October 2006 www.epa.gov/safewater
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