United States
Environmental Protection Office of Water EPA 570/F-91-045
Agency (WH-550) February 1991
S-EPA STANDARDIZED MONITORING ~
FRAMEWORK
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Standardized
li§iifi§
Framework
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U.S. EPA Office of Drinking Water ¦ Februarv 1991
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STANDARDIZED MONITORING FRAMEWORK
Background
Existing and forthcoming regulations under the Safe Drinking Water Act (SDWA)
contain significant monitoring requirements for public water systems. These requirements
vary by factors such as type of contaminant, system size and vulnerability status. Because a
uniform schedule or framework for monitoring did not exist, EPA standardized monitoring
in the recently promulgated Phase II regulation for 38 inorganic and organic contaminants.
EPA's use of a standard monitoring framework will apply to future monitoring requirements
for inorganics, Volatile Organic Chemicals (VOCs), pesticides, and radionuclides. Kequiremen ts
for currently regulated contaminants will be integrated into the framework when the existing
regulations are revised.
Objective
The degree of variability among monitoring requirements poses both management and
technical barriers for states and water systems that are ultimately responsible for irnplemen ting
the regulations. Consequently, EPA desires to standardize and simplify monitoring
requirements and synchronize monitoring schedules where possible. Benefits of such action
include:
> Reducing the complexity of the monitoring workload from a technical and
managerial perspective for both states and water systems;
>- Leveling out the resource expenditure for monitoring and vulnerability
assessments;
>• Reducing sampling and vulnerability assessment costs.
>• Increasing water system compliance with monitoring requirements.
Applicability O"-' •" ¦
5> The monitoring framework applies to source related contaminants associated
with chronic health effects. Contaminants associated with chronic health efsects
include; VOCs, pesticides, radionuclides, and inorganic chemicals (with the
exception of nitrate/nitrite).
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[standard Framework, cont'd
>- Standard Monitoring Requirements
• All systems must sample at the base (or minimum) sampling frequencies.
• All systems have the same initial base sampling requirement regardless of
system size or water source (except for inorganics).
• Most systems have the same repeat base sampling requirement regardless of
system size or water source. However, differences for specific contaminants do
exist for pesticides based on system size (see Example 2).
• All systems which detect contamination must sample quarterly at each sampling
point detecting contamination until the state determines that the analytical
results are "reliably and dependably" below the MCL. Detection is defined as:
the MCL for the inorganics; 0.0005 mg/1 for the VOCs, and at the analytical
Method Detection Limit (MDL) for the pesticides and PCBs. In addition to the
original sample, ground water systems must take a minimum of two additional
quarterly samples and surface water systems a minimum of four additional
quarterly samples before the state can determine that analytical results are
. "reliably and dependably" below the MCL.
• "Reliably and dependably" below the MCL means that though the system
detects contaminants in its water supply, it has sufficient knowledge of the
source or extent of the contamination to predict that the MCL would not be
exceeded. Wide variations in the analytical results or analytical results near
the MCL would not meet the "reliably and dependably" test.
• Generally the repeat sampling requirements are reduced after initial
sampling. For example, the initial sampling requirement for the VOCs is 4
quarterly samples; the repeat sampling requirement is 1 sample annually.
• Waivers are available to all systems based upon a vulnerability assessment
and/or consideration of prior analytical results. Waivers either reduce the
sampling frequency (e.g. inorganics and VOCs) or eliminate any sampling
frequency (e.g. pesticides, asbestos, and unregulated contaminants). See
Examples 1-5.
>¦ Grandfathering of Data
• At a system's (or state's) discretion, sampling data collected three years prior to
the beginning of the initial three-year monitoring period can be used to satisfy
the initial sampling requirements. Systems using this grandfather provision
would then sample at the repeat frequencies which generally are lower than the
initial frequencies.
• Vulnerability assessments may not be grandfathered.
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The Standard Framework
>• 3/6/9 Monitoring Cycle
• A nine-year compliance cycle (beginning in 1993) is established for all public
water systems.
• Each nine-year compliance schedule is divided into three three-year compliance
periods.
• All compliance cycles and compliance periods operate on a calendar year basis
(January 1 to December 31).
• The firstnine-year cycle begins January 1,1993 and ends December 31,2001. The
second nine-year cycle begins January 1,2002 and ends December 31,2010 and
so on.
• Within the first compliance cycle, the first compliance period begins January 1,
1993 and ends December 31,1995; the second begins January 1,1996 and ends
December31,1998; the third begins January 1,1999 and ends December 31,2001.
• The Federal requirement to phase-in monitoring by system size and communi ty /
non-transient water system classification is eliminated.
• Instead, EPA will require states to schedule approximately one-third of the
systems to monitor during each year of the three-year compliance period. Each
state has the flexibility to establish its own monitoring plan. For example, states
may prioritize monitoring based on system size, vulnerability, lab capacity, and
community/non-transient non-community criteria.
• Once a state schedules a system to monitor during a particular year of the three-
year compliance period, (e.g. the system monitors in the second year of the
compliance period) that system must monitor in the same year in? subsequent
compliance periods, (e.g., the second year).
>- When Initial Monitoring Begins
• When a regulation is promulgated during the nine-year compliance cycle, the
initial round of monitoring is required in the first full three-year compliance
cycle which begins 18 months after the date of promulgation (the effective date
of the regulation). For example, if Phase V is promulgated in March 1992, the
effective date is September 1993 (18 months after promulgation) in the middle
of the first three-year period. Consequently, the initial round of monitoring
would not begin until the second three-year compliance period (1996 - 1998).
This means initial monitoring for Phase V contaminants would be conducted
during the second three-year monitoring periods (1996 - 1998) and the repeat
monitoring period would begin in 1999.
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'§
»
Waivers & Vulnerability
Assessments
Waivers
EPA has established provisions whereby States may waive (either eliminate or reduce)
base sampling requirements if certain conditions are met Waivers based on vulnerability
assessments are granted for three year periods. There are two basic types of waivers:
1) Waiver by Rule: For systems meeting established criteria. Example: inorganics
where three samples less than the MCL axe the criteria. All systems (regardless
of size) can qualify for waivers. Systems which do not receive waivers must
sample at the regulatory minimum.
2) Waiver by Vulnerability Assessment
>- A simplified two-step waiver procedure is available to all systems.
Step # 1: "Use Waiver" - Was the contaminant used, manufactured, stored or
disposed of in the area. If not, a waiver is granted. If yes or
unknown, system determines susceptibility.
Example: pesticides
Step # 2; "Susceptability Waiver" - If a "use" waiver can. not be granted, a
thorough vulnerability assessment of the water source must be
done to determine "susceptibility" to contamination.
"Susceptibility" considers:
• Prior analytical and/or vulnerability assessment results;
• Environmental persistence and transport of the contaminant;
• How well the source is protected;
• Wellhead Protection Program reports; and
• Elevated nitrate levels.
Systems with no known "susceptibility" to contamination, based
upon an assessment of the above facts, may be granted a waiver
by the state. If "susceptibility" can not be determined, a system is
not eligible for a waiver. Systems which do not receive a waiver
must monitor at the regulatory minimum (i.e. base requiremen t)
Example: VOCs.
>- The State, the system, or a third party organization can conduct the
assessment. However, the state must approve the assessment.
>• Systems which do not receive waivers must sample at required base
frequencies.
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Standard Framework, cont'd
>• Waivers
• Base sampling requirements apply to all systems unless the; requirements are
waived (either reduced or eliminated) by the state. I
• All waivers are granted by the state based upon a vulnerability assessment or
evaluation, of prior analytical results.
• Waivers obtained for asbestos, pesticides, and unregulated contaminants relieve
the system of any sampling requirements. Waivers for inorganics or VOC's
reduce the sampling frequency. Waivers are not available forjnitrate and nitrite.
• • Waivers based on vulnerability assessments are effective for three-years for
pesticides, up to six years for VOCs, and up to nine years for the inorganics.
After the waiver expires a new vulnerability assessment (generally an update of
the previous assessment) is required to obtain a waiver.
• The extent of the vulnerability assessment depends on whether the system(s) in
question had monitoring data available or the results of a previous assessment.
The lack of data would necessitate a more extensive vulnerAbility assessment.
Minimum criteria for vulnerability assessments are specified in each regulation.
• A waiver must be granted for each specific contaminant. Waivers are based
upon an assessment of a system's vulnerability, which includes its previous
monitoring results. "
4
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Standardized
Monitoring
Framework
DATE
EVENT
COMMENTS
91
> Phase 11 promulgated - Jan, 1991
92
>- Phase II effective-July 1992
> Phase V promulgated -1992
93
to
95
3 Year Monitoring Period
First
9
Year
Compliance
Cycle
> Initial monitoring begins for
Phase II -1993
96
to
98
3 Year Monitoring Period
1
>• Repeat monitoring for Phase ii
99
to .
2001
3 Year Monitoring Period
1
>• Repeat monitoring for Phase ii
2002 .
to
2004
3 Year Monitoring Period
Second
9
Year
2005
to
2007
3 Year Monitoring Period
Compliance
Cycle
1
2006
to
2010
3 Year Monitoring Period
1
7
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D2
Nine-Year
Drinking Water Monitoring
Compliance Cycle
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6
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D2
EXAMPLE
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Standardized Monitoring Framework:
Pesticides
CALENDAR
YEAR
BASE REQUIREMENTS:
ALL SYSTEMS
REDUCED MONITORING:
SYSTEMS WfTHNO
PREVIOUS DETECTION
WAIVERS
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1991
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Systems Serving;
> 3,300 - 2 samples at
each sampling point
< 3,300 -1 sample at
each sampling point
Waiver
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1999
2000
2001
2002
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2004
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Systems Serving:
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4 quarterly
samples at each
sampling point
I
Systems Serving:
> 3-300 - 2 samples at
each sampling point
< 3,300 -1 sample at
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Waiver
Waiver
NOTE: States will designate the year during each compliance
period in which each system must monitor.
Based on "use" and/or
"susceptibility" assessment
(No Samples Required)
9
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tXAXir LC
Standardized Monitoring Framework:
CWS and NTWS
Asbestos
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CALENDAR
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1993
1994
1995
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1 sample at
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WAIVERS
(ALL SYSTEMS)
Waivers Based on
Vulnerability
Assessment
(No Samples Required)
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1997
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Not Applicable
Waivers Based on
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1 sample at
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NOTE: States will designate the year during each compliance
period in which each system must monitor.
8
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Standardized Monitoring Framework:
Volatile Organic Chemicals
CALENDAR
YEAR
BASE REQUIREMENTS:
ALL SYSTEMS
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I
!: Provided Initial monitoring completed by 12/31/92
and the system had no detection.
2: Reduction allowed after no detection in 'three years
of annual monitoring. ^ ^
NOTE:
States will designate the year
during each compliance per.
in which each system must mc
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Standardized Monitoring Framework:
Inorganics
CWS and NTWS
T
State may waive the base
monitoring requirements
after 3 samples of less than
the MCI are taken
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NOTE: States will designate the year during each compliance
period in which each system must monitor.
10
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*
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D2
Standardized Monitoring Framework;
Unregulated Contaminants
CALENDAR
YEAR
BASE REQUIREMENTS:
ALL SYSTEMS
WAIVERS
Organics
Inorganics
1991
lillisiw
1992
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1994
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samples at each
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Waiver
NOTE: States will designate the year during each compliance
period in which each system must monitor.
Based on 'use* and/or
'susceptibility* assessment
(No Samples Required)
12
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