SEPA
United States
Environmental Protection
Agency

The Standardized Monitoring Framework:
A Quick Reference Guide
Overview of the Framework
Title*
The Standardized Monitoring Framework (SMF), promulgated in the
Phase II Rule on January 30, 1991 (56 FR 3526).
Purpose
To standardize, simplify, and consolidate monitoring requirements across contaminant
groups. The SMF increases public health protection by simplifying monitoring plans and
synchronizing monitoring schedules leading to increased compliance with monitoring
requirements.
General
Description
The SMF reduces the variability within monitoring requirements for chemical and
radiological contaminants across system sizes and types.
*This document provides a summary of federal drinking water requirements; to ensure full compliance,
please consult the federal regulations at 40 CFR 141 and any approved state requirements.
Additional Requirements
The SMF outlined on these pages summarizes existing systems' ongoing federal monitoring frequencies
only, primacy agencies may have more stringent requirements. Primacy agencies with an EPA-approved
waiver program have the flexibility to issue waivers, which take into account regional and state specific
characteristics and concerns. To determine exact monitoring frequencies, the SMF must be used in
conjunction with any EPA approved waiver program and/or additional requirements as determined by the
primacy agency.
Additional sampling to confirm a result also may be required. New water systems may have different and
additional requirements as determined by the primacy agency.
For additional information:
Access the EPA Safe Drinking
Water website at https://www.epa.
gov/safewater or contact your
primacy agency's drinking water
representatives.
See 40 CFR 141.23 for lOCs,
nitrate, and nitrite; 40 CFR 141.24
for VOCs and SOCs; and 40 CFR
141.26 for Radionuclides.
Regulated Contaminants
Inorganic
Contaminants (lOCs)
Fifteen (15)
(Nitrate, Nitrite, and Asbestos
are exceptions to SMF)
Synthetic Organic
Contaminants (SOCs)
8t
Volatile Organic
Contaminants (VOCs)
Fifty-One (51)
(Vinyl chloride for ground water
systems is an exception to SMF)
Radionuclides
Four (4)
(Does not include beta particles
and photon emitters)
Applicable PWS
All PWSs
Nitrate
Nitrite
CWSs
lOCs
SOCs
VOCs
Radionuclides
NTNCWSs
lOCs
SOCs
VOCs
Legend for SMF Tables
= 1 sample at each entry point to distribution system (EPTDS),
** = 2 quarterly samples at each EPTDS. Samples must be taken during 1 calendar year during each
3-year compliance period.
: 4 quarterly samples at each EPTDS within time frame designated by the primacy agency.
X = No sample required unless specified by primacy agency. However, waivers must be renewed at the
frequency shown and system must demonstrate that the sources are not vulnerable.
# = Systems must monitor at a frequency specified by the primacy agency.
Detect = Federally defined detection limit.
Office of Water (4606M)
EPA 816-F-20-002
May 2020

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STANDARDIZED MONITORING FRAMEWORK
1st Period
Fourth Cycle
2nd Period 3rd Period
1st Period
Fifth Cycle
2nd Period 3rd Period
CWSs & NTNCWSs
U
O
o
CM
o
CM
CM
O
CM
CM
CM
O
CM
CO
CM
o
CM
*3-
CM
O
CM
m
CM
o
CM
CO	00
CM	CM	CM
o	o	o
CM	CM	CM
0>	O	t-
CM	CO	CO
O	O	O
CM	CM	CM
CM
CO
o
CM
CO
CO
o
CM
*3-
CO
o
CM
Ground Water
m
CO
o
CM
CD
CO
o
CM
Waiver
< MCL and No Waiver
Reliably and Consistently < MCL2
I **** I
I **** I
**** I
> MCL or Not Reliably and Consistently < MCL
Surface Water
Waiver1
*
*
< MCL and No Waiver
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
Reliably and Consistently < MCL2
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
> MCL or Not Reliably and Consistently < MCL3
****
****
****
****
****
****
****
****
****
****
****
****
****
****
****
****
****
****

CWSs & NTNCWSs
O
CM
T—
CM
CM
CM
CO
CM
*3-
CM
m
CM
CO
CM
1^
CM
CO
CM
o>
CM
o
CO
T—
CO
CM
CO
CO
CO
*3-
CO
in
CO
CO
CO
1^
CO

All Population Sizes

Reliably and Consistently < MCL2 4 5 6
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
> Detect or Not Reliably and Consistently < MCL3
****
****
****
****
****
****
****
****
****
****
****
****
****
****
****
****
****
****
Waiver with Vulnerability Assessment Every 3 Years7






< Detect and No Waiver
Population > 3,300
Population < 3,300
< Detect and No Waiver
CWSs & NTNCWSs
Ground Water
| Waiver with Vulnerability Assessment Every 3 Years7!
< Detect and No Waiver9
< Detect After at Least 3 Annual Samples11
Reliably and Consistently < MCL2'
> Detect or Not Reliably and Consistently < MCL3
Surface Water
Waiver with Vulnerability Assessment Every 3 Years7
X
X
X
X
X
X
< Detect and No Waiver9
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
Reliably and Consistently < MCL2 4 5
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
> Detect or Not Reliably and Consistently < MCL3
****
****
****
****
****
****
****
****
****
****
****
****
****
****
****
****
****
****
CWSs & NTNCWSs
O
CM
T—
CM
CM
CM
CO
CM
*3-
CM
m
CM
CO
CM
CM
CO
CM
o>
CM
o
CO
T—
CO
CM
CO
CO
CO
*3-
CO
in
CO
CO
CO
1^
CO
Waiver with Vulnerability Assessment Every 3 Years11
X
X
X
X
X
X
No Waiver, Reliably and Consistently < MCL,2 or Vulnerable
to Asbestos Contamination12
*
*
> MCL or Not Reliably and Consistently < MCL3
****
****
****
****
****
****
****
****
****
****
****
****
****
****
****
****
****
1 **** 1

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STANDARDIZED MONITORING FRAMEWORK
Period
Fourth Cycle
2nd Period
3rd Period
1st Period
Fifth Cycle
2nd Period
3rd Period
CWSs & NCWSs
Ground Water
o>	O	t-
CM	CO	CO
o	o	o
CM	CM	CM
< 1/2 MCL
Reliably and Consistently < MCL21
>1/2 MCL13 or Not Reliably and Consistently < MCL
After 4 Consecutive Quarters < 1/2 MCL5
s 1/2 MCL Within Last Four Quarters11
Ground Water and Surface Water TNCWSs
All Systems1:
< 1/2 MCL
CWSs & NCWSs
Reliably and Consistently < MCL21
> 1/2 MCL or Not Reliably and Consistently < MCL
< Detect15
*
*
*
> Detect and < 1/2 MCL
*
*
*
> 1/2 MCL and < MCL
*
*
*
*
*
*
> MCL316
****
****
****
****
****
****
****
****
****
****
****
****
****
****
****
****
****
****
1Based on 3 rounds of monitoring at each EPTDS with all analytical results < MCL. No monitoring
required for cyanide waivers provided that the primacy agency determines that the system is not
vulnerable due to lack of any industrial source of cyanide.
2A result above a trigger level triggers quarterly sampling at that EPTDS. Trigger level is > MCL for
lOCs; > detection limit for VOCs and SOCs; and > 1/2 MCL for nitrate and nitrite. Frequency may
be reduced if the primacy agency determines the sampling point is reliably and consistently (R&C)
< MCL. No R&C < MCL determination may be made for surface water systems for nitrate.
3lf the running annual average (RAA) of quarterly sampling is > MCL, the system remains on
quarterly monitoring until it meets the conditions to be determined R&C < MCL.
4Systems can apply for a waiver after 3 consecutive annual sampling results are below the
detection limit.
5Annual samples must be taken during the quarter which previously resulted in the highest
analytical result.
6Primacy agencies must re-confirm every 3 years that the system is not vulnerable or the system
must sample based on system population and no waiver.
7Systems must update their vulnerability assessments during the time the waiver is effective.
Primacy agencies must re-confirm every 3 years that a system is not vulnerable or the system
must return to annual monitoring.
8Waiver is effective for two compliance periods (6 years), and these periods can span compliance
cycles.
9lf all monitoring results during initial quarterly monitoring are < the detection limit, the system can
take annual samples. Systems are also eligible for a waiver.
10After a minimum of 3 years of annual sampling all results < the detection limit, they can take 1
sample during each compliance period. Systems are also eligible for a waiver.
"Primacy agencies must reconfirm every 3 years that the system is not vulnerable or the system
must return to 1 sample in the first 3-year compliance period of every 9-year compliance cycle.
12Systems are required to monitor for asbestos during the first 3-year compliance period of each
9-year compliance cycle. A system vulnerable to asbestos contamination due solely to corrosion
of asbestos-cement pipe must take 1 sample at a tap served by that pipe. A system vulnerable to
asbestos contamination at the source must sample at each EPTDS.
13An MCL of 20 mg/L may be approved by the primacy agency for NCWSs that do not supply
water to children under 6 months of age and additional criteria are met. [CFR 141.11(d)],
"Radionuclides information below specifies the requirements for gross alpha particle activity,
radium-226, radium-228, and uranium. Beta particle and photon radioactivity are not included,
refer to CFR 141.26(b) for more details.
15Systems must collect at least one sample every nine years if average of initial monitoring results
is < detect.
16Systems must sample at least four consecutive quarters with results below the MCL before the
monitoring frequency can be reduced.

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