310 CMR 22.07F
Stage 2 Disinfection Byproducts Requirements (DBPR)
(1) Initial Distribution System Evaluations.
(a) General Requirements. The requirements of 310 CMR 22.07F(1) through (6) establish
monitoring and other requirements for identifying Stage 2 DBPR compliance monitoring
locations under 310 CMR 22.07(F) for determining compliance with Maximum Contaminant
Levels for Total Trihalomethanes (TTHM) and Haloacetic Acids (Five) (HAA5). The
Supplier of Water must use an Initial Distribution System Evaluation (IDSE) to determine
locations with representative high TTHM and HAA5 concentrations throughout their
Distribution System. IDSEs are used in conjunction with, but separate from, compliance
monitoring required by 310 CMR 22.07E, to identify and select compliance monitoring
locations under 310 CMR 22.07F(6).
(b) Applicability. For Community Water Systems that use a primary or residual
Disinfectant other than ultraviolet light or deliver water that has been treated with a primary
or residual Disinfectant other than ultraviolet light; or a Non-transient Non-community Water
System that serves at least 10,000 people and uses a primary or residual Disinfectant other
than ultraviolet light or delivers water that has been treated with a primary or residual
Disinfectant other than ultraviolet light.
(c) Schedule.
1. Each Supplier of Water must comply with the requirements of the schedule in the
table in 310 CMR 22.20F(1)(c).
TABLE 1 – 310 CMR 22.07F
INITIAL DISTRIBUTION SYSTEM EVALUATION SCHEDULE
If you serve this population
Supplier of water must submit their
standard monitoring plan or system
specific study plan or 40/30 certification
to the Department by or receive very small
system waiver from the Department
Supplier of water must
complete their standard
monitoring or system
specific study by
Supplier of water must
submit their IDSE report
to the Department by3
Systems that are not part of a Combined Distribution System and systems that serve the largest population in the Combined
Distribution System
a. $100,000
October 1, 2006
September 30, 2008
January 1, 2009
b. 50,000-99,999
April 1, 2007
March 31, 2009
July 1, 2009
c. 10,000-49,999
October 1, 2007
September 30, 2009
January 1, 2010
d. < 10,000 (CWS Only)
April 1, 2008
March 31, 2010
July 1, 2010
Other systems that are part of a Combined Distribution System
e. Wholesale System or
consecutive system
--at the same time as the system with the
earliest compliance date in the Combined
Distribution System
--at the same time as the
system with the earliest
compliance date in the
Combined Distribution
System
--at the same time as the
system with the earliest
compliance date in the
Combined Distribution
System
If, within 12 months after the date identified in this column, the Department does not approve the
Supplier of Water’s plan or notify them that it has not yet completed its review, the Supplier of Water
may consider the plan that was submitted as approved.
The Supplier of Water must implement that plan and they must complete standard monitoring or a
system specific study no later than the date identified in the third column. The supplier of water must
submit their 40/30 certification under 310 CMR 22.20F(4) by the date indicated.
If, within three months after the date identified in this column (nine months after the date identified in
this column if the Supplier of Water must comply on the schedule in 310 CMR 22.07F(1)(c)1.c., the
Department does not approve their IDSE report or notify them that it has not yet completed its review,
the Supplier of Water may consider the report that was submitted as approved and must implement the
recommended monitoring in 310 CMR 22.07F as required.
22.07F: continued
2. For the purpose of the schedule in 310 CMR 22.07F(1)(c)1., the Department may
determine that the Combined Distribution System does not include certain consecutive
systems based on factors such as receiving water from a Wholesale System only on an
Emergency basis or receiving only a small percentage and small volume of water from
a Wholesale System. The Department may also determine that the Combined
Distribution System does not include certain Wholesale Systems based on factors such
as delivering water to a consecutive system only on an Emergency basis or delivering
only a small percentage and small volume of water to a consecutive system.
(d) The Supplier of Water must conduct standard monitoring that meets the requirements
in 310 CMR 22.20F(2), or a system specific study that meets the requirements in 310 CMR
22.07F(3), or certify to the Department that they meet 40/30 certification criteria under
310 CMR 22.20F(4), or qualify for a very small system waiver under 310 CMR 22.07F(5).
1. The Supplier of Water must have taken the full complement of routine TTHM and
HAA5 compliance samples required of a system with their population and source water
under 310 CMR 22.07E (or they must have taken the full complement of reduced TTHM
and HAA5 compliance samples required of a system with their population and source
water under 310 CMR 22.07E if they meet reduced monitoring criteria under 310 CMR
22.07E) during the period specified in 310 CMR 22.07F(4)(a) to meet the 40/30
certification criteria in 310 CMR 22.07F(4). The Supplier of Water must have taken
TTHM and HAA5 samples under 310 CMR 22.07E(6) and (7) to be eligible for the very
small system waiver in 310 CMR 22.07F(5).
2. If the Supplier of Water has not taken the required samples, they must conduct
standard monitoring that meets the requirements in 310 CMR 22.07F(2), or a system
specific study that meets the requirements in 310 CMR 22.07F(3).
(e) The Supplier of Water must use only the analytical methods specified in 310 CMR
22.07E(6), or otherwise approved by EPA for monitoring under 310 CMR 22.07F, to
demonstrate compliance with the requirements of 310 CMR 22.07F.
(f) IDSE results will not be used for the purpose of determining compliance with MCLs in
310 CMR 22.07E(1).
(2) Standard Monitoring.
(a) Standard Monitoring Plan. The standard monitoring plan must comply with 310 CMR
22.07F(2)(a)1. through 4. The Supplier of Water must prepare and submit their standard
monitoring plan to the Department according to the schedule in 310 CMR 22.07F(1)(c).
1. The standard monitoring plan must include a schematic of the Supplier of Water's
Distribution System (including Distribution System entry points and their sources, and
storage facilities), with notes indicating locations and dates of all projected standard
monitoring, and all projected compliance monitoring required under 310 CMR 22.07E.
2. The standard monitoring plan must include justification of standard monitoring
location selection and a summary of data relied on to justify standard monitoring location
selection.
3. The standard monitoring plan must specify the population served and system type
(Surface Water or Groundwater under the Direct Influence of Surface Water or
Groundwater).
4. The Supplier of Water must retain a complete copy of their standard monitoring plan
submitted under 310 CMR 22.07F(2)(a), including any Department modification of the
standard monitoring plan, for as long as the Supplier of Water is required to retain their
IDSE report under 310 CMR 22.07(2)(c)4.
(b) Standard Monitoring.
1. The Supplier of Water must monitor as indicated in the table in 310 CMR
22.07F(2)(b)1. The supplier must collect Dual Sample Sets at each monitoring location.
One sample in the Dual Sample Set must be analyzed for TTHM. The other sample in
the Dual Sample Set must be analyzed for HAA5. The Supplier of Water must conduct
one monitoring period during the peak historical month for TTHM levels or HAA5 levels
or the month of warmest water temperature. The Supplier of Water must review
available compliance, study, or operational data to determine the peak historical month
for TTHM or HAA5 levels or warmest water temperature.
22.07F: continued
TABLE 2 – 310 CMR 22.07F
STANDARD MONITORING
Source water type
Population size
category
Monitoring
periods and
frequency of
sampling
Distribution System monitoring locations1
Total per
monitoring
period
Near entry
points
Average
residence
Time
High TTHM
locations
High HAA5
locations
Surface Water
and Groundwater
under the Direct
Influence of
Surface Water
<500 consecutive
systems
One (during peak
historical month)2
.........
<500 non-consecutive
systems
.........
.........
.........
500-3,300
consecutive systems
Four
(every 90 days)
.........
500-3,300 non-
consecutive
systems
.........
.........
.........
3,301-9,999
.........
.........
10,000-49,999
Six
(every 60 days)
50,000-249,999
.........
250,000-999,999
.........
1,000,000-4,999,999
.........
>5,000,000
.........
Groundwater
<500 consecutive
systems
One (during peak
historical month)2
.........
<500 non-
consecutive
systems
.........
.........
.........
500-9,999
Four
(every 90 days)
.........
.........
10,000-99,999
.........
100,000-499,999
.........
>500,000
.........
A Dual Sample Set (i.e., a TTHM and an HAA5 sample) must be taken at each monitoring location
during each monitoring period.
The peak historical month is the month with the highest TTHM or HAA5 levels or the warmest water
temperature.
2. The Supplier of Water must take samples at locations other than the existing
monitoring locations required in 310 CMR 22.07E. Monitoring locations must be
distributed throughout the Distribution System.
3. If the number of entry points to the Distribution System is fewer than the specified
number of entry point monitoring locations, excess entry point samples must be replaced
equally at high TTHM and HAA5 locations. If there is an odd extra location number, the
Supplier of Water must take a sample at a high TTHM location. If the number of entry
points to the Distribution System is more than the specified number of entry point
monitoring locations, the Supplier of Water must take samples at entry points to the
Distribution System having the highest annual water flows.
4. The Supplier of Water's monitoring under 310 CMR 22.07F(2)(b) may not be
reduced under the provisions of 310 CMR 22.12.
(c) IDSE Report. The Supplier of Water's IDSE report must include the elements required
in 310 CMR 22.07F(2)(c)1. through 4. The Supplier of Water must submit their IDSE report
to the Department according to the schedule in 310 CMR 22.07F(1)(c).
22.07F: continued
1. The Supplier of Water's IDSE report must include all TTHM and HAA5 analytical
results from compliance monitoring under 310 CMR 22.07E and all standard monitoring
conducted during the period of the IDSE as individual analytical results and LRAAs
presented in a tabular or spreadsheet format acceptable to the Department. If changed
from their standard monitoring plan submitted under 310 CMR 22.07F(2)(a), the
Supplier of Water's report must also include a schematic of their Distribution System, the
population served, and system type (Surface Water or Groundwater under the Direct
Influence of Surface Water or Groundwater).
2. The Supplier of Water's IDSE report must include an explanation of any deviations
from their approved standard monitoring plan.
3. The Supplier of Water must recommend and justify compliance monitoring locations
under 310 CMR 22.07F and timing based on the protocol in 310 CMR 22.07F(6).
4. The Supplier of Water must retain a complete copy of their IDSE report submitted
under 310 CMR 22.07F(2)(c) for ten years after the date that they submitted their report.
If the Department modifies the monitoring requirements of 310 CMR 22.07F that the
Supplier of Water recommended in their IDSE report or if the Department approves
alternative monitoring locations, the Supplier of Water must keep a copy of the
Department's notification on file for ten years after the date of the Department's
notification. The Supplier of Water must make the IDSE report and any Department
notification available for review by the Department or the public.
(3) System Specific Studies.
(a) System Specific Study Plan. The Supplier of Water's system specific study plan must
be based on either existing monitoring results as required under 310 CMR 22.07F(3)(a)1. or
modeling as required under 310 CMR 22.07F(3)(a)2. The Supplier of Water must prepare
and submit their system specific study plan to the Department according to the schedule in
310 CMR 22.07F(1)(c).
1. Existing Monitoring Results. The Supplier of Water may comply by submitting
monitoring results collected before they are required to begin monitoring under 310 CMR
22.07F(1)(c). The monitoring results and analysis must meet the criteria in 310 CMR
22.07F(3)(a)1.a and b.
a. Minimum Requirements.
i. TTHM and HAA5 results must be based on samples collected and analyzed
in accordance with 310 CMR 22.07E(6). Samples must be collected no earlier
than five years prior to the study plan submission date.
ii. The monitoring locations and frequency must meet the conditions identified
in 310 CMR 22.07F(3)(a)1.a.ii. Each location must be sampled once during the
peak historical month for TTHM levels or HAA5 levels or the month of warmest
water temperature for every 12 months of data submitted for that location.
Monitoring results must include all monitoring results required under 310 CMR
22.07E plus additional monitoring results as necessary to meet minimum sample
requirements.
22.07F: continued
TABLE 3 – 310 CMR 22.07F
EXISTING MONITORING RESULTS REQUIRED
System Type
Population size category
Number of monitoring
locations
Number of samples
TTHM
HAA5
Surface and Groundwater
under the Direct Influence
of Surface Water
<500
500-3,300
3,301-9,999
10,000 – 49,999
50,000-249,999
250,000-999,999
1,000,000-4,999,999
>5,000,000
Groundwater
<500
500-9,999
10,000-99,999
100,000-499,999
>500,000
b. Reporting Monitoring Results. The Supplier of Water must report the following
information:
i. The Supplier of Water must report previously collected monitoring results and
certify that the reported monitoring results include all compliance and
non-compliance results generated during the time period beginning with the first
reported result and ending with the most recent results required under 310 CMR
22.07E.
ii. The Supplier of Water must certify that the samples were representative of
the entire Distribution System and that treatment, and Distribution System have
not changed significantly since the samples were collected.
iii. The Supplier of Water's study monitoring plan must include a schematic of
their Distribution System (including Distribution System entry points and their
sources, and storage facilities), with notes indicating the locations and dates of
all completed or planned system specific study monitoring.
iv. The Supplier of Water's system specific study plan must specify the
population served and system type (Surface Water or Groundwater under the
Direct Influence of Surface Water or Groundwater)
v. The Supplier of Water must retain a complete copy of their system specific
study plan submitted under 310 CMR 22.07F(3)(a)1., including any Department
modification of their system specific study plan, for as long as they are required
to retain their IDSE report under 310 CMR 22.07F(3)(b)7.
vi. If the Supplier of Water submits previously collected data that fully meets
the number of samples required under 310CMR 22.07F(3)(a)1.a.ii. and the
Department rejects some of the data, the Supplier of Water must either conduct
additional monitoring to replace rejected data on a schedule the Department
approves or conduct standard monitoring under 310 CMR 22.07F(2).
2. Modeling. The Supplier of Water may comply through analysis of an extended
period simulation hydraulic model. The extended period simulation hydraulic model and
analysis must meet the criteria in 310 CMR 22.07F(3)(a)2.
a. Minimum Requirements.
i. The model must simulate 24-hour variation in demand and show a
consistently repeating 24 hour pattern of residence time.
ii. The model must represent the criteria listed in 310 CMR
22.07F(3)(a)2.a.ii.(A) through (I).
(A) 75% of pipe volume;
(B) 50% of pipe length;
(C) All pressure zones;
22.07F: continued
(D) All 12-inch diameter and larger pipes;
(E) All eight-inch and larger pipes that connect pressure zones, influence
zones from different sources, storage facilities, major demand areas, pumps,
and control valves, or are known or expected to be significant conveyors of
water;
(F) All six-inch and larger pipes that connect remote areas of a Distribution
System to the main portion of the system;
(G) All storage facilities with standard operations represented in the model;
and
(H) All active pump stations with controls represented in the model; and
(I) All active control valves.
iii. The model must be calibrated, or have calibration plans, for the current
configuration of the Distribution System during the period of high TTHM
formation potential. All storage facilities must be evaluated as part of the
calibration process. All required calibration must be completed no later than 12
months after plan submission.
b. Reporting Modeling. The Supplier of Water's system specific study plan must
include the information in 310 CMR 22.07F(3)(a)2.b.
i. Tabular or spreadsheet data demonstrating that the model meets requirements
in 310 CMR 22.07F(3)(a)2.a.ii.
ii. A description of all calibration activities undertaken, and if calibration is
complete, a graph of predicted tank levels versus measured tank levels for the
storage facility with the highest residence time in each pressure zone, and a time
series graph of the residence time at the longest residence time storage facility in
the Distribution System showing the predictions for the entire simulation period
(i.e., from time zero until the time it takes to for the model to reach a consistently
repeating pattern of residence time).
iii. Model output showing preliminary 24-hour average residence time
predictions throughout the Distribution System.
iv. Timing and number of samples representative of the Distribution System
planned for at least one monitoring period of TTHM and HAA5 dual sample
monitoring at a number of locations no less than would be required for the system
under standard monitoring in 310 CMR 22.07F(2) during the historical month of
high TTHM. These samples must be taken at locations other than existing
compliance monitoring locations under 310 CMR 22.07E.
v. Description of how all requirements will be completed no later than 12
months after the Supplier of Water submits their system specific study plan.
vi. Schematic of the Supplier of Water's Distribution System (including
Distribution System entry points and their sources, and storage facilities), with
notes indicating the locations and dates of all completed system specific study
monitoring (if calibration is complete) and all compliance monitoring required
under 310 CMR 22.07E.
vii. Population served and system type (Surface Water and Groundwater Under
the Direct Influence of Surface Water or Groundwater).
viii. The Supplier of Water must retain a complete copy of their system specific
study plan submitted under 310 CMR 22.07F(3)(a)2., including any Department
modification of the system specific study plan, for as long as the Supplier of
Water is required to retain their IDSE report under 310 CMR 22.07F(3)(b)7.
c. If the Supplier of Water submits a model that does not fully meet the
requirements under 310 CMR 22.07F(3)(a)2., the Supplier of Water must correct the
deficiencies and respond to Department inquiries concerning the model. If the
Supplier of Water fails to correct deficiencies or respond to inquiries to the
Department's satisfaction, they must conduct standard monitoring under 310 CMR
22.07F(2).
(b) IDSE Report. The Supplier of Water's IDSE report must include the elements required
in 310 CMR 22.07F(3)(b)1. through 6. The Supplier of Water must submit their IDSE report
according to the schedule in 310 CMR 22.07F(1)(c).
22.07F: continued
1. The Supplier of Water's IDSE report must include all TTHM and HAA5 analytical
results from monitoring required under 310 CMR 22.07E and all system specific study
monitoring conducted during the period of the system specific study presented in a
tabular or spreadsheet format acceptable to the Department. If changed from the Supplier
of Water's system specific study plan submitted under 310 CMR 22.07F(3)(a), their IDSE
report must also include a schematic of their Distribution System, the population served,
and system type (Surface Water and Groundwater under the Direct Influence of Surface
Water or Groundwater).
2. If the Supplier of Water used the modeling provision under 310 CMR 22.07F(3)(a)2.,
they must include final information for the elements described in 310 CMR
22.07F(3)(a)2.b., and a 24-hour time series graph of residence time for each compliance
monitoring location selected in 310 CMR 22.07F.
3. The Supplier of Water must recommend and justify compliance monitoring locations
in 310 CMR 22.07F and timing based on the protocol in 310 CMR 22.07(6).
4. The Supplier of Water's IDSE report must include an explanation of any deviations
from their approved system specific study plan.
5. The Supplier of Water's IDSE report must include the basis (analytical and modeling
results) and justification they used to select the recommended monitoring locations in
310 CMR 22.07F(6).
6. The Supplier of Water may submit their IDSE report in lieu of their system specific
study plan on the schedule identified in 310 CMR 22.07F(1)(c) for submission of the
system specific study plan if they believe that they have the necessary information by the
time that the system specific study plan is due. If the Supplier of Water elects this
approach, their IDSE report must also include all information required under 310 CMR
22.07F(3)(a).
7. The Supplier of Water must retain a complete copy of their IDSE report submitted
under 310 CMR 22.07F(3)(b) for ten years after the date that they submitted their IDSE
report. If the Department modifies the monitoring requirements in 310 CMR 22.07F that
the Supplier of Water recommended in their IDSE report or if the Department approves
alternative monitoring locations, the Supplier of Water must keep a copy of the
Department's notification on file for ten years after the date of the Department's
notification. The Supplier of Water must make the IDSE report and any Department
notification available for review by the Department or the public.
(4) 40/30 Certification.
(a) Eligibility. The Supplier of Water is eligible for 40/30 certification if they had no
TTHM or HAA5 monitoring violations under 310 CMR 22.07E and no individual sample
exceeded 0.040 mg/L for TTHM or 0.030 mg/L for HAA5 during an eight consecutive
calendar quarter period beginning no earlier than the date specified in 310 CMR
22.07F(4)(a).
TABLE 4 – 310 CMR 22.07F
40/30 CERTIFICATION SCHEDULE
If your 40/30 certification is due
Then your eligibility for 40/30 certification is based
on eight consecutive calendar quarters of
compliance monitoring results under 310 CMR
22.07E beginning no earlier than1
1. October 1, 2006
January 2004
2. April 1, 2007
January 2004
3. October 1, 2007
January 2005
4. April 1, 2008
January 2005
Unless the Supplier of Water is on reduced monitoring under 310 CMR 22.07E and was not required
to monitor during the specified period. If they did not monitor during the specified period, they must
base their eligibility on compliance samples taken during the 12 months preceding the specified period.
22.07F: continued
(b) 40/30 Certification.
1. The Supplier of Water must certify to the Department that every individual
compliance sample taken under 310 CMR 22.07E during the periods specified in
310 CMR 22.07F(4)(a) were < 0.040 mg/L for TTHM and < 0.030 mg/L for HAA5, and
that they have not had any TTHM or HAA5 monitoring violations during the period
specified in 310 CMR 22.07F(4)(a).
2. The Department may require the Supplier of Water to submit compliance monitoring
results, Distribution System schematics, and/or recommended compliance monitoring
locations as required in 310 CMR 22.07F in addition to their certification. If the Supplier
of Water fails to submit the requested information, the Department may require standard
monitoring under 310 CMR 22.07F(2) or a system specific study under 310 CMR
22.07F(3).
3. The Department may still require standard monitoring under 310 CMR 22.07F(2) or
a system specific study under 310 CMR 22.07F(3) even if the Supplier of Water meets
the criteria in 310 CMR 22.07F(4)(a).
4. The Supplier of Water must retain a complete copy of their certification submitted
under 310 CMR 22.07F(4)(b) for ten years after the date that they submitted their
certification. The Supplier of Water must make the certification, all data upon which the
certification is based, and any Department notification available for review by the
Department or the public.
(5) Very Small System Waivers.
(a) If the Supplier of Water serves fewer than 500 people and it has taken TTHM and HAA5
samples under 310 CMR 22.07E, the Supplier of Water is not required to comply with 310
CMR 22.07F(1) unless the Department notifies the Supplier of Water that it must conduct
standard monitoring under 310 CMR 22.07F(2) or a system specific study under 310 CMR
22.07F(3).
(b) If the Supplier of Water has not taken TTHM and HAA5 samples under 310 CMR
22.07E or if the Department notifies the Supplier of Water that it must comply with
310 CMR 22.07F(1), the Supplier of Water must conduct standard monitoring under
310 CMR 22.07F(2) or a system specific study under 310 CMR 22.07F(3).
(6) Compliance Monitoring Location Recommendations.
(a) The Supplier of Water's IDSE report must include their recommendations and
justification for where and during what month(s) TTHM and HAA5 monitoring required
under 310 CMR 22.07F(8) should be conducted. They must base their recommendations on
the criteria in 310 CMR 22.07F(6)(b) through (e).
(b) The Supplier of Water must select the number of monitoring locations specified in the
table in 310 CMR 22.07F(6)(b). The Supplier of Water will use these recommended
locations as routine compliance monitoring locations under 310 CMR 22.07F, unless the
Department requires different or additional locations. The Supplier of Water should
distribute locations throughout the Distribution System to the extent possible.
22.07F: continued
TABLE 5 – 310 CMR 22.07F
DISTRIBUTION SYSTEM MONITORING LOCATIONS
Distribution System monitoring location
Source water type
Population size
category
Monitoring
frequency1
Total per
monitoring
period2
Highest
TTHM
locations
Highest
HAA5
locations
Existing
compliance
locations under
310 CMR 22.07E
Surface or
Groundwater under
the Direct Influence
of Surface Water
<500
Per year
...........
500-3,300
Per quarter
3,301-9,999
Per quarter
...........
10,000-49,999
Per quarter
50,000-249,999
Per quarter
250,000-999,999
Per quarter
1,000,000-4,999,999
Per quarter
>5,000,000
Per quarter
Groundwater
<500
Per year
500-9,999
Per year
10,000-99,999
Per quarter
100,000-499,999
Per quarter
>500,000
Per quarter
All systems must monitor during month of highest DBP concentrations.
Systems on quarterly monitoring must take Dual Sample Sets every 90 days at each monitoring location,
except for Surface Water and Groundwater under the Direct Influence of Surface Water systems serving
500-3,300. Groundwater systems serving 500 9,999 on annual monitoring must take Dual Sample Sets
at each monitoring location. All other systems on annual monitoring and Surface Water and
Groundwater under the Direct Influence of Surface Water systems serving 500-3,300 are required to take
individual TTHM and HAA5 samples (instead of a Dual Sample Set) at the locations with the highest
TTHM and HAA5 concentrations, respectively. For systems serving fewer than 500 people, only one
location with a Dual Sample Set per monitoring period is needed if highest TTHM and HAA5
concentrations occur at the same location and month.
(c) The Supplier of Water must recommend compliance monitoring locations for 310 CMR
22.07F(6) based on standard monitoring results, system specific study results, and
compliance monitoring results required under 310 CMR 22.07E. The Supplier of Water
must follow the protocol in 310 CMR 22.07F(6)(c)1. through 8. If required to monitor at
more than eight locations, the Supplier of Water must repeat the protocol as necessary. If the
Supplier of Water does not have existing compliance monitoring results required under
310 CMR 22.07E or if they do not have enough existing compliance monitoring results
required under 310 CMR 22.07E, they must repeat the protocol, skipping the provisions of
310 CMR 22.07F(6)(c)(3) and (7) as necessary, until they have identified the required total
number of monitoring locations.
1. Location with the highest TTHM LRAA not previously selected as a monitoring
location under 310 CMR 22.07F.
2. Location with the highest HAA5 LRAA not previously selected as a monitoring
location under 310 CMR 22.07F.
3. Existing average residence time compliance monitoring location (maximum
residence time compliance monitoring location for groundwater systems) under
310 CMR 22.07E with the highest HAA5 LRAA not previously selected as a monitoring
location under 310 CMR 22.07F.
4. Location with the highest TTHM LRAA not previously selected as a monitoring
location under 310 CMR 22.07F.
5. Location with the highest TTHM LRAA not previously selected as a monitoring
location under 310 CMR 22.07F.
22.07F: continued
6. Location with the highest HAA5 LRAA not previously selected as a monitoring
location under 310 CMR 22.07F.
7. Existing average residence time compliance monitoring location (maximum
residence time compliance monitoring location for groundwater systems) under
310 CMR 22.07E with the highest TTHM LRAA not previously selected as a monitoring
location under 310 CMR 22.07F.
8. Location with the highest HAA5 LRAA not previously selected as a monitoring
location under 310 CMR 22.07F.
(d) The Supplier of Water may recommend locations other than those specified in 310 CMR
22.07F(6)(c) if they include a rationale for selecting other locations. If the Department
approves the alternate locations, they must monitor at these locations to determine
compliance under 310 CMR 22.07F.
(e) The Supplier of Water's recommended schedule must include monitoring required under
310 CMR 22.07F during the peak historical month for TTHM and HAA5 concentration,
unless the Department approves another month. Once the Supplier of Water has identified
the peak historical month, and if they are required to conduct routine monitoring at least
quarterly, they must schedule compliance monitoring required under 310 CMR 22.07F at a
regular frequency of every 90 days or fewer.
(7) General Monitoring Requirements of Stage 2 Disinfection Byproducts Rule.
(a) General. The requirements of 310 CMR 22.07F(7) through (16) establish monitoring
and other requirements for achieving compliance with Maximum Contaminant Levels based
on Locational Running Annual Averages (LRAA) for Total Trihalomethanes (TTHM) and
Haloacetic Acids (Five) (HAA5), and for achieving compliance with maximum residual
Disinfectant residuals for chlorine and chloramine for certain consecutive systems.
(b) Applicability. The Supplier of Water is subject to these requirements if their system is
a Community Water System or a Non-transient Non-community Water System that uses a
primary or residual Disinfectant other than ultraviolet light or delivers water that has been
treated with a primary or residual Disinfectant other than ultraviolet light.
(c) Schedule. The Supplier of Water must comply with the requirements in 310 CMR
22.07F(7) on the schedule in the following table based on their system type.
TABLE 6 – 310 CMR 22.07F
MONITORING SCHEDULE
If you are this type of system
You must comply with monitoring required under 310 CMR 22.07F(7) by:1
Systems that are not part of a Combined Distribution System and systems that serve the largest population in the Combined
Distribution System
1. System serving > 100,000
April 1, 2012
2. System serving 50,000 99,999
October 1, 2012
3. System serving 10,000 49,999
October 1, 2013
4. System serving < 10,000
October 1, 2013 if no Cryptosporidium monitoring is required under 310 CMR
22.20G(2)(a)4. or
October 1, 2014 if Cryptosporidium monitoring is required under 310 CMR
22.20G(2)(a)4. or 310 CMR 22.20G(2)(a)6.
Other systems that are part of a Combined Distribution System
5. Consecutive system or Wholesale System
at the same time as the system with the earliest compliance date in the
Combined Distribution System.
The Department may grant up to an additional 24 months for compliance with MCLs and operational
evaluation levels if the Supplier of Water requires capital improvements to comply with an MCL.
22.07F: continued
6. The Supplier of Water's monitoring frequency is specified in 310 CMR
22.07F(8)(a)2.
a. If the Supplier of Water is required to conduct quarterly monitoring, they must
begin monitoring in the first full calendar quarter that includes the compliance date
in the table in 310 CMR 22.07F(7)(c).
b. If the Supplier of Water is required to conduct monitoring at a frequency that is
less than quarterly, they must begin monitoring in the calendar month recommended
in the IDSE report prepared under 310 CMR 22.07F(2) or (3) or the calendar month
identified in the monitoring plan developed under 310 CMR 22.07F(9) no later than
12 months after the compliance date in the table in 310 CMR 22.07F(7)(c).
7. If the Supplier of Water is required to conduct quarterly monitoring, they must make
compliance calculations at the end of the fourth calendar quarter that follows the
compliance date and at the end of each subsequent quarter (or earlier if the LRAA
calculated based on fewer than four quarters of data would cause the MCL to be
exceeded regardless of the monitoring results of subsequent quarters). If the Supplier of
Water is required to conduct monitoring at a frequency that is less than quarterly, they
must make compliance calculations beginning with the first compliance sample taken
after the compliance date.
8. For the purpose of the schedule in 310 CMR 22.07F(7)(c), the Department may
determine that the Combined Distribution System does not include certain consecutive
systems based on factors such as receiving water from a Wholesale System only on an
Emergency basis or receiving only a small percentage and small volume of water from
a Wholesale System. The Department may also determine that the Combined
Distribution System does not include certain Wholesale Systems based on factors such
as delivering water to a consecutive system only on an Emergency basis or delivering
only a small percentage and small volume of water to a consecutive system.
(d) Monitoring and Compliance.
1. Systems Required to Monitor Quarterly. To comply with MCLs required by
310 CMR 22.07F listed in 310 CMR 22.07E(1), the Supplier of Water must calculate
LRAAs for TTHM and HAA5 using monitoring results collected under 310 CMR 22.07F
and determine that each LRAA does not exceed the MCL. If the Supplier of Water fails
to complete four consecutive quarters of monitoring, they must calculate compliance with
the MCL based on the average of the available data from the most recent four quarters.
If the Supplier of Water takes more than one sample per quarter at a monitoring location,
they must average all samples taken in the quarter at that location to determine a
quarterly average to be used in the LRAA calculation.
2. Systems Required to Monitor Yearly or less Frequently. To determine compliance
with MCLs required by 310 CMR 22.07F listed in 310 CMR 22.07E(1), the Supplier of
Water must determine that each sample taken is less than the MCL. If any sample
exceeds the MCL, they must comply with the requirements of 310 CMR 22.07F(12). If
no sample exceeds the MCL, the sample result for each monitoring location is considered
the LRAA for that monitoring location.
(e) Violation. The Supplier of Water is in violation of the monitoring requirements for each
quarter that a monitoring result would be used in calculating an LRAA if they fail to monitor.
(8) Routine Monitoring.
(a) Monitoring.
1. If the water supplier submitted an IDSE report, they must begin monitoring at the
locations and months they have recommended in their IDSE report submitted under
310 CMR 22.07F(6) following the schedule in 310 CMR 22.07F(7)(c), unless the
Department requires other locations or additional locations after its review. If the
Supplier of Water submitted a 40/30 certification under 310 CMR 22.07F(4) or they
qualified for a very small system waiver under 310 CMR 22.07F(5) or they are a
Non-transient Non-community Water System serving < 10,000, they must monitor at the
location(s) and dates identified in their monitoring plan in 310 CMR 22.07E(7)(f)
updated as required by 310 CMR 22.07F(9).
2. The Supplier of Water must monitor at no fewer than the number of locations
identified in 310 CMR 22.07F(8)(a)2.
22.07F: continued
TABLE 7 – 310 CMR 22.07F
ROUTINE MONITORING FREQUENCY
Source Water Type
Population Size Category
Monitoring Frequency
Distribution System
monitoring location total
per monitoring period 2
Surface Water and
Groundwater under the Direct
Influence of Surface Water
<500
Per year
500-3,300
Per quarter
3,301-9,999
Per quarter
10,000-49,999
Per quarter
50,000-249,999
Per quarter
250,000-999,999
Per quarter
1,000,000-4,999,999
Per quarter
>5,000,000
Per quarter
Groundwater
<500
Per year
500-9,999
Per year
10,000-99,999
Per quarter
100,000-499,999
Per quarter
>500,000
Per quarter
All systems must monitor during month of highest DBP concentrations.
Systems on quarterly monitoring must take Dual Sample Sets every 90 days at each monitoring location,
except for systems using Surface Water or Groundwater under the Direct Influence of Surface Water
systems and serving 500-3,300. Groundwater systems serving 500-9,999 on annual monitoring must
take Dual Sample Sets at each monitoring location. All other systems on annual monitoring and systems
using Surface Water or groundwater systems under the direct influence of surface water systems serving
500-3,300 are required to take individual TTHM and HAA5 samples (instead of a Dual Sample Set) at
the locations with the highest TTHM and HAA5 concentrations, respectively. For systems serving fewer
than 500 people, only one location with a Dual Sample Set per monitoring period is needed if highest
TTHM and HAA5 concentrations occur at the same location and month.
3. If the Supplier of Water is an undisinfected system that begins using a Disinfectant
other than UV light after the dates in 310 CMR 22.07F(1) for complying with the Initial
Distribution System Evaluation requirements, they must consult with the Department to
identify compliance monitoring locations for 310 CMR 22.07F(8). The Supplier of
Water must then develop a monitoring plan under 310 CMR 22.07F(9) that includes
those monitoring locations.
(b) Analytical Methods. The Supplier of Water must use an approved method listed in
310 CMR 22.07E(6) for TTHM and HAA5 analyses in 310 CMR 22.07F(8). Analyses must
be conducted by laboratories that have received certification by EPA or the Department as
specified in 310 CMR 22.07E(6).
(9) Monitoring Plan.
(a) 1. The Supplier of Water must develop and implement a monitoring plan to be kept on
file for Department and public review. The monitoring plan must contain the elements
in 310 CMR 22.07F(9)(a)1.a. through d. and be completed no later than the date the
Supplier of Water conducts their initial monitoring under 310 CMR 22.07F(8).
a. Monitoring locations;
b. Monitoring dates;
c. Compliance calculation procedures; and
d. Monitoring plans for any other systems in the Combined Distribution System if
the Department has reduced monitoring requirements.
22.07F: continued
2. If the Supplier of Water was not required to submit an IDSE report under either
310 CMR 22.07F(2) or (3), and they do not have sufficient monitoring locations required
under 310 CMR 22.07E to identify the required number of compliance monitoring
locations indicated in 310 CMR 22.07F(6)(b), they must identify additional locations by
alternating selection of locations representing high TTHM levels and high HAA5 levels
until the required number of compliance monitoring locations have been identified. They
must also provide the rationale for identifying the locations as having high levels of
TTHM or HAA5. If the Supplier of Water has more monitoring locations required under
310 CMR 22.07E than required for compliance monitoring in 310 CMR 22.07F(6)(b),
they must identify which locations they will use for compliance monitoring under
310 CMR 22.07F(8) by alternating selection of locations representing high TTHM levels
and high HAA5 levels until the required number of compliance monitoring locations
under 310 CMR 22.07F(8) have been identified.
(b) If the Supplier of Water is a Surface Water or a Groundwater under the Direct Influence
of Surface Water serving > 3,300 people, they must submit a copy of their monitoring plan
to the Department prior to the date they conduct their initial monitoring under 310 CMR
22.07F(8), unless their IDSE report submitted under 310 CMR 22.07F(2) contains all the
information required by 310 CMR 22.07F(9).
(c) The Supplier of Water may revise their monitoring plan to reflect changes in treatment,
Distribution System operations and layout (including new service areas), or other factors that
may affect TTHM or HAA5 formation, or for Department-approved reasons, after
consultation with the Department regarding the need for changes and the appropriateness of
changes. If the Supplier of Water changes monitoring locations, they must replace existing
compliance monitoring locations with the lowest LRAA with new locations that reflect the
current Distribution System locations with expected high TTHM or HAA5 levels. The
Department may also require modifications in their monitoring plan. If they are a Surface
Water or Groundwater under the Direct Influence of Surface Water system serving > 3,300
people, they must submit a copy of their modified monitoring plan to the Department prior
to the date they are required to comply with the revised monitoring plan.
(10) Reduced Monitoring.
(a) The Supplier of Water may reduce monitoring to the level specified in the table in
310 CMR 22.07F(10)(a) any time the LRAA is < 0.040 mg/L for TTHM and < 0.030mg/L
for HAA5 at all monitoring locations. They may only use data collected under the provisions
of 310 CMR 22.07E or 22.07F to qualify for reduced monitoring. In addition, the source
water annual average TOC level, before any treatment, must be < 4.0 mg/L at each treatment
plant treating Surface Water or Groundwater Under the Direct Influence of Surface Water,
based on monitoring conducted under 310 CMR 22.07E(7)(b)1.c. or (d).
22.07F: continued
TABLE 8 – 310 CMR 22.07F
REDUCED MONITORNG FREQUENCY AND LOCATION
Source water type
Population size
category
Monitoring
frequency1
Distribution System monitoring location per
monitoring period
Surface Water or Groundwater under
the Influence of Surface Water
<500
................... Monitoring may not be reduced.
500-3,300
Per year
1 TTHM and 1 HAA5 sample: one at the location
and during the quarter with the highest TTHM
single measurement, one at the location and during
the quarter with the highest HAA5 single
measurement; 1 Dual Sample Set per year if the
highest TTHM and HAA5 measurements occurred
at the same location and quarter.
3,301-9,999
Per year
2 Dual Sample Sets: one at the location and during
the quarter with the highest TTHM single
measurement, one at the location and during the
quarter with the highest HAA5 single measurement.
10,000-49,999
Per quarter
2 Dual Sample Sets at the locations with the highest
TTHM and highest HAA5 LRAAs.
50,000-249,999
Per quarter
4 Dual Sample Sets at the locations with the two
highest TTHM and two highest HAA5 LRAAs.
250,000-999,999
Per quarter
6 Dual Sample Sets at the locations with the three
highest TTHM and three highest HAA5 LRAAs.
1,000,000-4,999,999
Per quarter
8 Dual Sample Sets at the locations with the four
highest TTHM and four highest HAA5 LRAAs.
>5,000,000
Per quarter
10 Dual Sample Sets at the locations with the five
highest TTHM and five highest HAA5 LRAAs.
Groundwater
<500
Every third
year
1 TTHM and 1 HAA5 sample: one at the location
and during the quarter with the highest TTHM
single measurement, one at the location and during
the quarter with the highest HAA5 single
measurement; 1 Dual Sample Set per year if the
highest TTHM and HAA5 measurements occurred
at the same location and quarter.
500-9,999
Per year
1 TTHM and 1 HAA5 sample: one at the location
and during the quarter with the highest TTHM
single measurement, one at the location and during
the quarter with the highest HAA5 single
measurement; 1 Dual Sample Set per year if the
highest TTHM and HAA5 measurements occurred
at the same location and quarter.
10,000-99,999
Per year
2 Dual Sample Sets: one at the location and during
the quarter with the highest TTHM single
measurement, one at the location and during the
quarter with the highest HAA5 single measurement.
100,000-499,999
Per quarter
2 Dual Sample Sets at the locations with the highest
TTHM and highest HAA5 LRAAs.
>500,000
Per quarter
4 Dual Sample Sets at the locations with the two
highest TTHM and two highest HAA5 LRAAs.
Systems on quarterly monitoring must take Dual Sample Sets every 90 days.
22.07F: continued
(b) The Supplier of Water may remain on reduced monitoring as long as the TTHM LRAA
< 0.040 mg/L and the HAA5 LRAA < 0.030 mg/L at each monitoring location (for systems
with quarterly reduced monitoring) or each TTHM sample < 0.060 mg/L and each HAA5
sample < 0.045 mg/L (for systems with annual or less frequent monitoring). In addition, the
source water annual average TOC level, before any treatment, must be < 4.0 mg/L at each
treatment plant treating Surface Water or Groundwater under the Direct Influence of Surface
Water, based on monitoring conducted under either 310 CMR 22.07E(7)(b)1.c. or (d).
(c) If the LRAA based on quarterly monitoring at any monitoring location exceeds either
0.040 mg/L for TTHM or 0.030 mg/L for HAA5 or if the annual (or less frequent) sample
at any location exceeds either 0.060 mg/L for TTHM or 0.045 mg/L for HAA5, or if the
source water annual average TOC level, before any treatment, >4.0 mg/L at any treatment
plant treating Surface Water or Groundwater Under the Direct Influence of Surface Water,
the Supplier of Water must resume routine monitoring under 310 CMR 22.07F(8) or begin
increased monitoring if 310 CMR 22.07F(12) applies.
(d) The Department may return the Supplier of Water to routine monitoring at the
Department's discretion.
(11) Additional Requirements for Consecutive Systems. If the Supplier of Water is a
consecutive system that does not add a Disinfectant but delivers water that has been treated with
a primary or residual Disinfectant other than ultraviolet light, they must comply with analytical
and monitoring requirements for chlorine and chloramines in 310 CMR 22.07E(6)(c) and(7)(c)1.
and the compliance requirements in 310 CMR 22.07E(8)(c)1. beginning April 1, 2009, unless
required earlier by the Department, and report monitoring results under 310 CMR 22.07E(9)(c).
(12) Conditions Requiring Increased Monitoring.
(a) If the Supplier of Water is required to monitor at a particular location annually or less
frequently than annually under 310 CMR 22.07F(8) or (10), they must increase monitoring
to Dual Sample Sets once per quarter (taken every 90 days) at all locations if a TTHM
sample is >0.080 mg/L or a HAA5 sample is >0.060 mg/L at any location.
(b) The Supplier of Water is in violation of the MCL when the LRAA exceeds the Stage 2
Disinfection Byproducts MCLs in 310 CMR 22.07E(1), calculated based on four consecutive
quarters of monitoring (or the LRAA calculated based on fewer than four quarters of data if
the MCL would be exceeded regardless of the monitoring results of subsequent quarters).
The Supplier of Water is in violation of the monitoring requirements for each quarter that a
monitoring result would be used in calculating an LRAA if they fail to monitor.
(c) The Supplier of Water may return to routine monitoring once they have conducted
increased monitoring for at least four consecutive quarters and the LRAA for every
monitoring location is < 0.060 mg/L for TTHM and < 0.045 mg/L for HAA5.
(13) Operational Evaluation Levels.
(a) The Supplier of Water has exceeded the operational evaluation level at any monitoring
location where the sum of the two previous quarters' TTHM results plus twice the current
quarter's TTHM result, divided by four to determine an average, exceeds 0.080 mg/L, or
where the sum of the two previous quarters' HAA5 results plus twice the current quarter's
HAA5 result, divided by four to determine an average, exceeds 0.060 mg/L.
(b) 1. If the Supplier of Water exceeds the operational evaluation level, they must conduct
an operational evaluation and submit a written report of the evaluation to the Department
no later than 90 days after being notified of the analytical result that causes them to
exceed the operational evaluation level. The written report must be made available to the
public upon request.
2. The Supplier of Water's operational evaluation must include an examination of
system treatment and distribution operational practices, including storage tank
operations, excess storage capacity, Distribution System flushing, changes in sources or
source water quality, and treatment changes or problems that may contribute to TTHM
and HAA5 formation and what steps could be considered to minimize future
exceedences.
a. The Supplier of Water may request and the Department may allow them to limit
the scope of their evaluation if they are able to identify the cause of the operational
evaluation level exceedance.
22.07F: continued
b. The Supplier of Water's request to limit the scope of the evaluation does not
extend the schedule in 310 CMR 22.07F(13)(b)1. for submitting the written report.
The Department must approve this limited scope of evaluation in writing and the
Supplier of Water must keep that approval with the completed report.
(14) Requirements for Remaining on Reduced TTHM and HAA5 Monitoring Based on Results
Required under 310 CMR 22.07E. The Supplier of Water may remain on reduced monitoring
after the dates identified in 310 CMR 22.07F(7)(c) for compliance with 310 CMR 22.07F(14)
only if they qualify for a 40/30 certification under 310 CMR 22.07F(4) or have received a very
small system waiver under 310 CMR 22.07F(5), plus they meet the reduced monitoring criteria
in 310 CMR 22.07F(10)(a), and they do not change or add monitoring locations from those used
for compliance monitoring under 310 CMR 22.07E. If the Supplier of Water's monitoring
locations under 310 CMR 22.07F differ from their monitoring locations under 310 CMR 22.07E,
they may not remain on reduced monitoring after the dates identified in 310 CMR 22.07F(7)(c)
for compliance with 310 CMR 22.07F.
(15) Requirements for Remaining on Increased TTHM and HAA5 Monitoring Based on Results
Required under 310 CMR 22.07E. If the Supplier of Water was on increased monitoring under
310 CMR 22.07E(7)(b)1., they must remain on increased monitoring until they qualify for a
return to routine monitoring under 310 CMR 22.07F(12)(c). The Supplier of Water must
conduct increased monitoring under 310 CMR 22.07F(12) at the monitoring locations in the
monitoring plan developed under 310 CMR 22.07F(9) beginning at the date identified in
310 CMR 22.07F(7)(c) for compliance with 310 CMR 22.07F and remain on increased
monitoring until they qualify for a return to routine monitoring under 310 CMR 22.07F(12)(c).
(16) Reporting and Recordkeeping Requirements.
(a) Reporting.
1. The Supplier of Water must report the following information for each monitoring
location to the Department within ten days of the end of any quarter in which monitoring
is required:
a. Number of samples taken during the last quarter.
b. Date and results of each sample taken during the last quarter.
c. Arithmetic average of quarterly results for the last four quarters for each
monitoring location (LRAA), beginning at the end of the fourth calendar quarter that
follows the compliance date and at the end of each subsequent quarter. If the LRAA
calculated based on fewer than four quarters of data would cause the MCL to be
exceeded regardless of the monitoring results of subsequent quarters, they must
report this information to the Department as part of the first report due following the
compliance date or anytime thereafter that this determination is made. If the Supplier
of Water is required to conduct monitoring at a frequency that is less than quarterly,
they must make compliance calculations beginning with the first compliance sample
taken after the compliance date, unless they are required to conduct increased
monitoring under 310 CMR 22.07F(12).
d. Whether, based on 310 CMR 22.07E(1) and 22.07F, the MCL was violated at any
monitoring location.
e. Any operational evaluation levels that were exceeded during the quarter and, if
so, the location and date, and the calculated TTHM and HAA5 levels.
2. If the Supplier of Water is a Surface Water or Groundwater under the Direct
Influence of Surface Water system seeking to qualify for or remain on reduced
TTHM/HAA5 monitoring, they must report the following source water TOC information
for each treatment plant that treats Surface Water or Groundwater under the Direct
Influence of Surface Water to the Department within ten days of the end of any quarter
in which monitoring is required:
a. The number of source water TOC samples taken each month during last quarter.
b. The date and result of each sample taken during last quarter.
c. The quarterly average of monthly samples taken during last quarter or the result
of the quarterly sample.
d. The Running Annual Average (RAA) of quarterly averages from the past four
quarters.
e. Whether the RAA exceeded 4.0 mg/L.
22.07F: continued
3. The Department may choose to perform calculations and determine whether the MCL
was exceeded or the system is eligible for reduced monitoring in lieu of having the
system report that information.
(b) Recordkeeping. The Supplier of Water must retain any monitoring plans required under
310 CMR 22.07F and their monitoring results as required by 310 CMR 22.07E(8).