&EPA
United States
Environmental Protection
Agency
Office of Water (4601M)
Office of Ground Water and Drinking Water
Total Coliform Rule Issue Paper
Analysis of Compliance and Characterization of
Violations of the Total Coliform Rule
April 2007
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PREPARED FOR:
U.S. Environmental Protection Agency
Office of Ground Water and Drinking Water
Standards and Risk Management Division
1200 Pennsylvania Ave., NW
Washington DC 20004
PREPARED BY:
Environomics, Inc.
The Cadmus Group
Background and Disclaimer
The USEPA is revising the Total Coliform Rule (TCR) and is considering collecting data on
distribution as part of these revisions. As part of this process, the USEPA is publishing a series
of issue papers to present available information on topics relevant to possible TCR revisions.
This paper was developed as part of that effort.
The objectives of the issue papers are to review the available data, information and research
regarding the potential public health risks associated with the distribution system issues, and
where relevant identify areas in which additional research may be warranted. The issue papers
will serve as background material for EPA, expert and stakeholder discussions. The papers only
present available information and do not represent Agency policy. Some of the papers were
prepared by parties outside of EPA; EPA does not endorse those papers, but is providing them
for information and review.
Additional Information
The paper is available at the TCR web site at:
http://www.epa.gov/safewater/disinfection/tcr/requlation revisions.html
Questions or comments regarding this paper may be directed to TCR@epa.gov.
11
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CONTENTS
1. Overview 1
2. Need For Analysis of TCR Violations 5
3. Sources of Data 6
4. Characterization of the Inventory of Public Water Systems 11
5. Average of Annual TCR Violations Per Year from 1997 to 2003 17
6. TCR Violations by System Size 20
7. TCR Violations by System Type 24
8. Analysis of TCR Violations By Source Water 28
9. Analysis of Repeat Violators 32
10. Analysis of TCR Violations Over Time 37
11. More Recent TCR Violation Data 44
12. Analysis of TCR Violations by Treatment Technology 46
13. Analysis of TCR Violations by Season 47
14. Analysis of TCR Violations Associated with Outbreak Events 50
15. TCR Sanitary Survey Violations 52
16. Small System Issues 53
17. Summary 54
in
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Analysis of Compliance and Characterization of Violations of the Total
Coliform Rule
1. Overview
Total coliforms have long been used in drinking water regulations as an indicator of the
adequacy of water treatment and the integrity of the distribution system. Total coliforms are a
group of closely related bacteria that are generally harmless. In drinking water systems, total
coliforms react to treatment in a manner similar to most bacterial pathogens and many viral
pathogens. Thus, the presence of total coliforms in the distribution system can indicate that the
system in also vulnerable to the presence of pathogens in the system. (EPA, June 2001, page 7)
Total coliforms are the indicators used in the existing Total Coliform Rule (TCR).
EPA is undertaking "a rulemaking process to initiate possible revisions to the TCR. As
part of this process, EPA believes it may be appropriate to include this rulemaking in a wider
effort to review and address broader issues associated with drinking water distribution systems."
(see Federal Register 68 FR 19030 and 68 FR 42907). Since the promulgation of the TCR, EPA
has received stakeholder feedback suggesting modifications to the TCR to reduce the
implementation burden.
The purpose of this paper is to provide information on the number and frequency of
violations of the TCR and to further characterize the frequency with which different types and
sizes of systems incur violations. Although EPA explores some statistical testing in this paper,
the paper concentrates on presenting the data, as it is, in SDWIS/FED. Information on these
frequencies will be useful in supporting several EPA initiatives, particularly the effort to review
and possibly revise the TCR. This paper has been undertaken as part of the review of the TCR.
Despite potential data quality concerns, this report uses TCR violations data as reported
in SDWIS/FED as the primary source due to the lack of an alternative source of national data.
See Section 3 for more information on the data used for this report and the associated data
quality.
The data on TCR violations presented in this paper can serve as a foundation for further
analysis and research. For example, while this paper presents comparisons of violations across
system sizes, categories, and sources, no attempt is made to explain reasons for any differences.
Next steps could include research on the impact of factors such as water quality, system
performance, and Monitoring & Reporting practices to explain the implications of differences in
violation rates.
1
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The Total Coliform Rule (TCR), which applies to all public water systems1, was
promulgated (i.e., published in the Federal Register) by the U.S. Environmental Protection
Agency in 1989, and became effective in 1991 (54 FR 27544-27568). The TCR requires systems
to monitor for total coliforms at points within the distribution system according to a State-
approved sample siting plan. The minimum Monitoring & Reporting frequency depends upon
the number of people a system serves and whether the system is a community water system
(CWS) or a noncommunity water system (NCWS)2. The required Monitoring & Reporting
frequency ranges from 480 samples per month for the largest CWSs to one sample per year for
certain small NCWSs.
If any routine sample is total coliform-positive, the system must test that positive culture
for the presence of either fecal coliforms oris, coli, both of which are a subgroup of the total
coliform group that, unlike total coliforms, are closely linked to fecal contamination. Fecal
coliforms are a subgroup of total coliforms that are likely to have come from sewage or a fecal
source. Hence, the presence of fecal coliforms in the distribution system is a more direct
indication of possible fecal contamination and the possible attendant health impacts. E. coli is a
subset of fecal coliforms that is commonly found in the intestines of warm blooded animals.
Most strains of E. coli are harmless, but some strains such as 0157:H7 are pathogenic and can
cause mild to serious health threats to humans (EPA, February 2002, page 8, 54 FR 27544-
27568).
After a total coliform-positive sample, the system must also take a set of three repeat
samples (four repeat samples for systems that take one sample per month or fewer) within five
service connections of the routine sample, and at least five routine samples the next month of
operation. Both routine and repeat samples count toward compliance with the maximum
contaminant levels (MCLs) for total coliforms. If a system normally takes fewer than five routine
samples per month (normally systems serving 4,100 or fewer), it must undergo an on-site
sanitary survey every five years (ten years for a noncommunity water system that uses protected
and disinfected ground water). This analysis does not address compliance with disinfection
residual monitoring requirements because such requirements do not fall under the TCR. The
TCR Monitoring & Reporting requirements are summarized in Exhibit 1.
1A public water system (PWS) is a system for the provision to the public of water for human consumption
through pipes or other constructed conveyances, if such system has at least fifteen service connections or regularly
serves at least twenty-five individuals. (Federal Register: August 5, 1998 (Volume 63, Number 150))
2
Community Water System (CWS): A public water system that supplies water to the same population year-
round. Non-Transient Non-Community Water System (NTNCWS): A public water system that regularly supplies
water to at least 25 of the same people at least six months per year, but not year-round. Transient Non-Community
Water System (TNCWS): A public water system that provides water in a place such as a gas station or campground
where people do not remain for long periods of time, (http://www.epa.gov/ogwdw/pws/factoids.html)
2
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Exhibit 1: Summary of TCR Sampling Requirements
Routine Sampling Requirements
•
•
•
•
•
Total coliform samples must be collected at sites which are representative of water quality
throughout the distribution system according to a written sample siting plan subject to state review
and revision.
Samples must be collected at regular time intervals throughout the month except groundwater
systems serving 4,900 persons or fewer, that may collect them on the same day.
Monthly sampling requirements are based on population served
A reduced Monitoring & Reporting frequency may be available for systems serving 1,000 persons
or fewer and using only ground water if a sanitary survey within the past 5 years shows the system
is free of sanitary defects (the frequency may be no less than 1 sample/quarter for community and
1 sample/year for non-community systems).
Each total coliform-positive routine sample must be tested for the presence of fecal coliforms or E.
coli.
If any routine sample is total coliform-positive, repeat samples are required.
•
Repeat Sampling Requirements
•
•
•
Within 24 hours of learning of a total coliform-positive ROUTINE sample result, at least 3 REPEAT
samples must be collected and analyzed for total coliforms:
o One REPEAT sample must be collected from the same tap as the original sample,
o One REPEAT sample must be collected within five service connections upstream,
o One REPEAT sample must be collected within five service connections downstream.
Systems that collect 1 ROUTINE sample per month or fewer must collect a 4th REPEAT sample.
If any REPEAT sample is total coliform-positive:
o The system must analyze that total coliform-positive culture for fecal coliforms or E. coli.
o The system must collect another set of REPEAT samples, as before, unless the MCL has
been violated and the system has notified the state.
Additional Routine Sampling Requirements
•
A positive ROUTINE or REPEAT total coliform result requires a minimum of five ROUTINE
samples be collected the following month the system provides water to the public unless waived by
the state.
Source: EPA, November 2001.
Compliance with the TCR is determined by both the completion of Monitoring &
Reporting requirements (determined by system size and type) and by the presence or absence of
total coliforms in those required samples. Monthly MCL violations are incurred by the presence
of TC only while Acute MCL Violations require the presence of either coli or fecal coliform.
Incomplete Monitoring & Reporting or under-reporting triggers MR violations. The following
paragraphs more fully define the different types of TCR violations:
• An Acute MCL Violation: If a system has a total coliform-positive routine sample, and
at least one of the required repeat samples is E. coli or fecal coliform-positive or if a
system has an E. coli or fecal-positive routine sample and at least one of the required
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repeat samples is total-coliform-positive, the system has an acute MCL violation.3 When
an acute MCL violation occurs, the system must notify the State by the end of the day
that the system is notified of the test result (unless the system is notified of the result after
the State office is closed, in which case the system must notify the State before the end of
the next business day). The system must also notify the public no later than 24 hours after
the violation occurs (revised from no later than 72 hours under the revised Public
Notification Rule). An Acute MCL violation is considered to be indicative of a serious
potential health risk.
• A Monthly or Nonacute MCL Violation: If a system takes fewer than forty routine
samples per month (i.e., serves 33,000 people or fewer) to comply with the MCL for total
coliforms, no more than one sample/month can be total coliform-positive. If a system
takes at least 40 samples per month, no more than 5.0% of the samples collected during a
month can be total coliform-positive. If a sample violates the nonacute MCL, the system
must notify the State within 48 hours and the public no later than 30 days after the
violation occurs (revised from no later than 14 days under the revised Public Notification
Rule). A Monthly MCL Violation poses a less serious but still significant potential health
risk.
• A Monitoring & Reporting Violation refers to a failure to take and properly report the
required number and type of samples during a time period. A Monitoring & Reporting
Violation does not per se represent a health risk, but failure to sample and report could
result in a failure to detect contamination. (EPA, November 2001, page 1). The TCR
establishes the following Monitoring & Reporting violations.
ROUTINE:
Major:
Minor:
REPEAT:
Major:
Minor:
A failure to take all (takes no samples) of the required routine samples per
compliance period.
A failure to take some (but not all) of the required routine samples in a
compliance period.
A failure to conduct follow up Monitoring & Reporting after a total
coliform-positive sample (i.e., takes no repeat samples and/or conducts no
speciation for fecal/is. colt).
A failure to take some of the required repeat samples and/or a failure to
speciate at least one (but not all) total coliform-positive samples for
fecal/is. coli.
3 States may invalidate total coliform positive repeat samples under certain conditions, detailed in CFR 141.21(c).
4
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In addition, violations can be associated with: (1) failure to undergo sanitary survey
within the specified time line, as required; (2) failure to report to the State within specified time
lines after an MCL violation; and (3) failure to notify the public within specified time lines after
an MCL violation.
2. Need For Analysis of TCR Violations
Analysis of TCR violations will assist EPA in gauging the magnitude of non-compliance
with the TCR, patterns of non-compliance (if any), and possibly the implications of non-
compliance. This information will be used in the current effort to review and possibly revise the
TCR. Understanding the nature and frequency of existing violations to the TCR will help EPA
assess the current TCR approach and will inform the development and consideration of
alternatives. In this report, the following sections contain the analyses of TCR violation data
from 1997 to 2003.
• In Section 5, the number of systems and the fraction of systems that have had TCR
Acute, Monthly, and/or Monitoring & Reporting violations were examined. Information
on the number of systems incurring violations will indicate the scope of non-compliance
and possible health risks, and support analysis of compliance.
• The fraction of systems incurring violations is important when looking at comparisons
between categories or over time. For example, one would expect a greater number of
small systems to incur violations, simply because there are a greater number of small
systems. Also, the inventory of systems is changing over time. Examining the percent of
systems per category normalizes the data and puts it on a consistent basis.
• Also, the number of TCR Acute, Monthly, and/or Monitoring & Reporting violations and
the distribution of the violations per system were examined. The number of violations is
also important in indicating the scope of non-compliance and possible health risks and
supporting analysis of compliance.
• Further, the Violations per system allow us to identify the extent to which systems incur
multiple violations, perhaps indicating an ongoing health risk.
• In Section 6, the distribution of TCR violations by size of system4 is evaluated to identify
trends or problems with compliance based on system size.
• In Section 7, the distribution of TCR violations by type of system (CWS, NTNCWSs,
TNCWSs)5 is evaluated. The different types of systems serve different types of
4 Size categories: <=100; 101-500; 501-1,000; 1,001-3,300; 3,301-10,000; 10,001-50,000; 50,001-100,000;
>100,000
5
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populations over different time periods, thus making different types of health risks more
important for those systems.
• In Section 8, the distribution of TCR violations by the source water that supplies the
system (GW, SW, GU)6 is evaluated. Treatment requirements vary by the type of source
water used by a system. Analysis of TCR violations by source type can support analysis
for other rules and indicate possible differences based on treatment requirements and
water quality.
• In Section 9, analyses conducted to assess the degree to which systems incur violations
repeatedly over a number of years are described.
• In Section 10, the trends over time are analyzed for the changes with respect to inventory
characteristics and violations, and to determine if compliance is improving.
• In Section 11, more recent SDWIS/FED data that became available during the
development of this paper is considered.
• In Section 12, potential issues and questions related to an analysis relating TCR
violations to treatment technologies are addressed.
• In Section 13, analyses of variations in TCR violations across seasons are described.
• In Section 14, whether the systems that have experienced an outbreak also incurred a
TCR violation for the outbreak incidence is examined. This information would facilitate
the examination of the ability of TCR Monitoring & Reporting to serve as an indicator or
predictor of outbreak risk.
3. Sources of Data
The primary source of data on TCR violations used for this analysis is the Safe Drinking
Water Information System/Federal Version (SDWIS/FED). This national database stores basic
information for every public water system in the United States supplied by primacy agencies
(States, Territories, Tribes, and EPA Regions).
In SDWIS/FED, EPA maintains basic identifying information for all public water
systems, including:
5 Community Water Systems, Nontransient Noncommunity Water Systems, Transient Noncommunity
Water Systems
6 Groundwater, Surface Water, Groundwater under the Influence of Surface Water,
6
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• The nine character PWS ID number that uniquely identifies each public water system
• Whether the system is: a Community (year-round, residential population - e.g. a city);
Non-Transient Non-Community (serves the same population for at least six months a
year, although the system is not the primary water supplier - e.g. many businesses or
schools); or Transient Non-Community (varying population - e.g. a rest area) water
system
• The number of people regularly served by the water system
• The number of service connections for each water system (defined as the number of
households or businesses connected to the water system)
• Basic information on a water system's source of water
• Water system owner type (local, state or federal government, private, etc.)
SDWIS/FED also contains information on violations, including TCR MCL and
Monitoring & Reporting violations. Violation information contained in SDWIS/FED include:
• A violation ID number which uniquely identifies the violation
• The type of violation that has occurred (MCL Acute, MCL Monthly, treatment technique,
or Monitoring & Reporting Routine: Major, Routine: Minor, Repeat: Major, Repeat:
Minor)
• The time period during which the violation occurred
• The date the state or EPA region became aware of the violation (for certain contaminants)
• For Monitoring & Reporting violations, whether it is a major or minor violation,
depending on the contaminant and the number of samples taken (EPA, October 1998,
pages 1-5)
States report violations data to SDWIS/FED every quarter. The data used in this analysis
represents the contents of SDWIS/FED as of January 1, 2004, which means that the information
is current through end of the 2003 federal fiscal year (Sept 30, 2003). The analyses contain
information from FY 1997 through FY 2003. The version of SDWIS/FED inventory data used in
this analysis was provided in data warehouse tables created by OGWDW in July 2004.
The quality of data stored in SDWIS/FED varies by data item. In 2000 and 2003, EPA
prepared reports on the reliability of state reported public water system data in SDWIS/FED.
These reports are based on EPA's data verification audits conducted from FY 1999 through FY
2001. During the data verification audit:
7
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...personnel (EPA and contractor staff) review data submitted by public water systems,
state files and databases and SDWIS/FED [i.e., state versions of SDWIS/FED], and
compile results on errors (unreported, undetected, and incorrect violations) and
discrepancies (wrong information) in the data as compared to the data in SDWIS/FED
[i.e, the federal version ofSDWIS/FED]1
The results of the audit are expressed as the percentage of data without any discrepancies or
errors. Overall, the data quality of inventory data elements is high quality as rated in the data
verification report and shown in Exhibit 2.
Exhibit 2: SDWIS/FED Inventory Data Quality
Data Element
Data Quality
(% Data W/O Discrepancies or Errors)
2003
2000
PWS ID
100%
100%
Water System Type
98%
97%
Primary Source
98%
98%
Population Served
88%
91%
Overall Inventory
95%
96%
Source: EPA, March 2004, page 12
In general, the data quality value calculated in the data reliability report is a combination
of a measure of completeness (i.e., the percent of actual violations reported to SDWIS) and
accuracy (i.e., of the violations that were reported to SDWIS, the percent that were reported
without errors) under a certain assumption. For example, if 50% of actual violations were
reported to SDWIS (completeness measure) and 75% of the reported violations were error-free
(accuracy), the overall data quality score would be 37.5%8 given that there is no false-positive
error in reporting to SDWIS/FED. The data reliability report characterizes a data element as
being of low quality if the overall data quality score is from 0% to 70%, of moderate quality if
the overall score is between 71% to 90%, and of high quality if the score is from 91% to 100%.
Using this characterization, the data quality for the TCR violations data has been
moderate for the more important TCR MCL violations and low quality for Monitoring and
Reporting violations. The TCR MCL violations data has the highest quality of any MCL
violations data (compared with other rules), at 75% overall score, up from 68% in the previous
data verification report (EPA, October 2000). The overall data quality score of 75% for TCR
7 EPA, March 2004, pages 5-6.
8 50% x 75% = 37.5%
8
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MCL violations is a combination of a score of 81% for completeness and 93% for accuracy
(Exhibit 3) and is therefore classified as being of moderate quality. Thus, one can conclude that
the TCR MCL violations are under-reported to SDWIS/FED and the analyses conducted for this
report probably understate the actual occurrence of TCR MCL violations.
The data quality for all Monitoring & Reporting violations is low at 23%, which is
combination of the data completeness measure at 27% and accuracy at 89% (Exhibit 3).9 The
data quality specifically for TCR Monitoring & Reporting violation is the highest of any of the
Monitoring & Reporting categories for other rules at 41% (not shown in Exhibit 3), but is still
considered of low quality by the report. Based on the low data quality, it is likely that the
occurrence of TCR Monitoring & Reporting Violations may be underestimated by the data
(EPA, October 2000; EPA, March 2004).
Data quality varies slightly by the type of system. Data quality estimates for TCR MCL
violations are slightly higher for NTNCWSs and slightly lower for TNCWSs. For all Monitoring
& Reporting violations, data quality is better for TNCWSs. Exhibit 3 summarizes information on
data quality estimates by system type.
Exhibit 3: Data Quality Estimates for SDWIS-Reported Violations by PWS Type
Type of PWS
Year
TCR MCL Violation
Monitoring &
Reporting Violation
(ALL)
Overall Data Quality Score
CWS
2003
78%
18%
2000
69%
9%
NTNCWS
2003
81%
20%
2000
67%
7%
TNCWS
2003
65%
39%
2000
68%
14%
All Systems
2003
75%
23%
2000
68%
9%
Completeness Score
All Systems
2003
81%
27%
2000
68%
10%
Accuracy Score
All Systems
2003
93%
89%
2000
99%
95%
Source: EPA, March 2004, page 18
9
Exhibit 3 displays information for ALL Monitoring & Reporting violations. The referenced source
document does not provide equivalent information on TCR Monitoring & Reporting violations only.
9
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Despite potential data quality concerns, this report uses TCR violations data as reported
in SDWIS/FED as the primary source due to the lack of an alternative source of national data.
For inventory (e.g., system type, population served, etc.) and TCR MCL violations data, the
overall data quality is moderate to good. In addition, the accuracy of the TCR MCL data reported
in SDWIS/FED is excellent. For example, TCR MCL violations data were found to be 99%
accurate in 2000 and 93% accurate in 2003 (Exhibit 3); thus we can have a fair degree of
confidence that the data in SDWIS/FED is correctly reported. The TCR MCL violations data is
less complete (81% in 2003), leading one to conclude that our analyses may under-estimate
overall rates of violations by as much as 20%. However, since 81% of the data represents a large
majority of the data and because that 81% is highly accurate, the sample may be large enough to
be useful in revealing possible trends and might not be strongly influenced by the remaining 19%
of the data. Thus, the comparisons made using the MCL violations data (say among size
categories or over time) should be valid, assuming no reporting bias.
The TCR Monitoring & Reporting violations data is of lesser data quality and therefore
has more uncertainty involved in using and interpreting the data. In general, the accuracy of all
Monitoring & Reporting data in SDWIS/FED is good (95% in 2000 and 89% in 2003 for ALL
M&R violations)10. The completeness, however, is quite low for all M&R violations at 27% for
2003. The completeness for the TCR M&R violations, while not reported in the reference
document, is likely better than for all M&R violations, estimated at about 43% (assuming the
same level of accuracy as the overall M&R violations)11. Thus, the results reported in this paper
may under-estimate actual incidence of M&R violations by a fair degree.
The validity of the comparisons made in this paper using SDWIS data hinges on whether
the violations that are not reported to SDIWS vary in a substantial manner from the data that is
reported to SDWIS. For example, if the violations that are not reported to SDWIS tend to be
more heavily weighted to small systems, then the comparisons of violations rates among system
size categories may not accurately reflect actual differences. Subsequent analyses are underway
to characterize the composition of the under-reported TCR violations would be useful in
interpreting and validating the results presented in this paper.
In summary, although the data collected in SDWIS are not complete, particularly for
Monitoring and Reporting violations, analysis of this available data is a necessary first step in
evaluating potential revisions to the TCR.
The violation rates derived from SDWIS data and presented in the paper may also be
under-reported due to the actions of systems. For example, systems may be incurring a
Monitoring & Reporting violation in order to avoid an MCL violation. This issue is analyzed to
10 Data on the accuracy and completeness of TCR M&R violations is not available in the source document.
11 Assumes an overall data quality of 41% for TCR M&R violations as reported and an accuracy of 95%.
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a limited extent in the analysis of repeat violators, but it is impossible to determine the full extent
of this practice solely from the SDWIS data. In addition, systems could be using the invalidation
criteria to avoid violations. A further discussion of this issue can be found in the paper:
Invalidation of Total Coliform Positive Samples. Also, States may have different reporting
requirements which may impact the number and nature of violations that are included in SDWIS.
The differences in State requirements are beyond the scope of this paper and could be the subject
of future research.
4. Characterization of the Inventory of Public Water Systems
The first series of data analyses presented in this paper contain information on the
inventory of public water systems from 1997 through 2003. Inventory data is important to
understanding the characteristics of water systems and how those characteristics may have
changed over the period of analysis. Also, trends in these characteristics provide important
contexts for interpreting the violations data presented in later chapters.
For each of the data elements examined, this report presents a graphical representation of
the data, a table containing the values, and a few key points summarizing the data and
implications.
180,000
160,000
« 140,000
E
2. 120,000
W '
5> 100,000
° 80,000
-------
Key Points:
During the period of 1997 to 2003, the total number of active Public Water Systems
(PWSs) has exhibited an overall slight downward trend, decreasing about 5.55% (170,679 -
161,201)/170,679. The number of systems in all three categories also showed a downward trend:
CWSs had the smallest decline at 2.5% (54,684 - 53,363)/53,363. TNCWS had the largest
decline at 8.1% (95,898 - 88,152)/88,152. With respect to the distribution among the system
types, in 2003, 55% of PWSs were TNCWS, 12% were NTNCWS, and 33% were CWSs. This
distribution has remained steady since 1997, with a shift of 1% fewer TNCWS systems (56% in
1997 and 55% in 2003) and of 1% more CWSs (32% in 1997 and 33% in 2003).
Exhibit 5: Number of Systems by Source Water Type: 1997 - 2003
180,000 t
160,000 — nn —I
140,000 —
120,000 —
100,000 —
80,000 —
60,000 —
40,000 —
20,000 —
o __l — 1— —I r-
1997
1998
1999
2000
2001
2002
2003
¦ GU
404
480
510
600
959
1,058
1,085
~ SW
13,235
13,128
12,889
13,536
13,773
13,506
13,648
~ GW
157,028
156,768
154,328
153,697
150,739
146,752
146,468
TOTAL
170,667
170,376
167,727
167,833
165,471
161,316
161,201
Source: Data extracted from SDWIS/FED in January 2004.
Note: Inactive, closed, unknown source and "unclassified" PWSs are not included in counts.
Mixed systems are re-classified into other categories (i.e., GU, GW, SW).
GU: Groundwater under the influence of surface water and purchased groundwater
under the influence of surface water
GW: Groundwater and purchased groundwater
SW: Surface water and purchased surface water
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Key Points:
In 2003, the large majority (90.9%) of systems used groundwater as a source, with 0.7%
using groundwater under the influence and 8.5% using surface water. Although a small fraction
of systems, the number of systems that use groundwater under the influence has more than
doubled from 1997 to 2003, both in terms of actual numbers (404 to 1,085) and as a percent of
systems (0.2% to 0.7%) (404/170,667 to 1,085/161,201). The increase in systems using
groundwater under the influence may be due to reclassification of existing systems or the use of
new sources. The percent of systems using surface water has increased slightly from 1997 to
2003 (7.8%) to 8.5%>) (12,235/170,667 to 13,648/161,201) while the percent of systems using
groundwater has decreased slightly (92.0% to 90.9%) (157,028/170,667 to 146,468/161,201).
Exhibit 6: Number of Systems by Size: 1997 - 2003
Source: Data extracted from SDWIS/FED in January 2004.
180,000
160,000
140,000
(A
| 120,000
(A
W 100,000
o) 80,000
n
E
D
60.000
40.000
20.000
2000
2002 2003
444
2.946
2.911
2.919
3.014
3.037
3.016
3.075
4,588
9.645
4,566
9.583
4,609
9.541
4,686
9.604
4.712
4,799
9.716
4,879
9.749
9.722
9.925
10.006
10.008
10.020
10.057
9.990
10.088
43,471
99,371
44,048
98,460
43,573
96.254
43,722
95.961
43,463
93.661
42,667
90.307
42,932
89.636
170.679
170.376
167,734
167.845
165,471
161,316
161,201
~ >100,000
~ 50,001-100,000
~ 10,001-50,000
~ 3,301-10,000
~ 1,001-3,300
~ 501-1,000
TOTAL
13
-------
Key Points:
In 2003, of the total of 161,201 systems, 157,284 systems were systems serving fewer
than 10,000, a size category that accounts for 97.6% of all systems. Medium and large systems
make up a small fraction of the total number of systems: 2.4% (367+475+3,075)/161,201. The
number of systems in the two smallest size categories (<100 and 101-500) declined from 1997 to
2003. All other size categories experienced an increase in the number and percent of systems,
although the amount of change was small.
14
-------
Exhibit 7: Number of Systems by Size and Type: 2003
90,000
80,000
70,000
| 60,000
I
100,000
4
I NTNCWS
~ CWS
9,725
14,067
7,060
16,350
1,999
6,072
787
8,322
97
4,686
15
3,032
1
473
2
361
Source: Data extracted from SDWIS/FED in January 2004.
Key Points:
There are substantial differences in the distribution of system types across the size
categories. Overall, there are far more systems in the small size category than in the larger
categories. Also, the larger the size category, the greater the fraction of CWSs and the smaller
the fraction of TNCWSs. For example, CWSs make up 15.7% (14,067/89,636) of systems
<=100, but 96% (4,686/4,879) in the 3,301-10,000 category. A very small portion (around 1%
(28+l+4+15+l+2)/(3,032+473+361)) of medium and large systems are noncommunity water
systems (NTNCWSs or TNCWSs). There are two TNCWSs that serve greater than 1,000,000:
Griffith Park in Los Angeles that has 10,000,000 visitors per year and the New York State Fair,
which is listed as serving 2,000,000 visitors. Both systems use purchased surface water.
15
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Exhibit 8: Population Served by System Size: 1997 - 2003
300,000,000
250,000,000
T3
100,000
~ 50,001-100,000
~ 10,001-50,000
110,674,195
28,966,560
64,178,849
114,034,401
30,258,269
64,120,670
115,255,430
30,087,194
64,559,276
117,597,748
32,744,165
65,914,742
117,459,598
31,698,906
66,605,594
131,861,342
30,798,367
66,154,372
134,698,282
32,488,171
67,250,025
~ 3,301-10,000
¦ 1,001-3,300
~ 501-1,000
26,655,225
17,978,517
7,351,355
26,545,944
17,890,734
7,426,354
26,730,434
17,817,316
7,417,966
27,076,077
17,935,521
7,414,074
27,219,285
18,173,429
7,440,477
27,722,321
18,095,624
7,372,544
28,235,885
18,185,188
7,451,360
1101-500
I <=100
Total
10,437,059
4,685,300
270,927,060
10,565,661
4,689,705
275,531,738
10,476,234
4,608,118
276,951,968
10,522,357
4,588,295
283,792,979
10,444,154
4,508,613
283,550,056
10,227,602
4,372,796
296,604,968
10,289,255
4,364,801
302,962,967
Source: Data extracted from SDWIS/FED in January 2004.
Key Points:
Although small systems make up the majority of the total number of systems, they serve
a small fraction of the population. For example, in 2003, systems in the smallest size category
(<=100) make up 56% of the total number of systems, but serve only 1.4%
(4,364,801/302,962,967) of the population. The fraction of the population served has decreased
slightly across all system categories serving fewer than 50,000. The fraction of the population
served has remained the same in the 50,001-100,000 category and has increased in the >100,000
category.
16
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5. Average of Annual TCR Violations Per Year from 1997 to 2003
The series of data presented in this section and following sections contains information
on the averages of TCR violations during the period of 1997-2003 where annual average is
calculated as the total violations incurred from 1997 until 2003 divided by 7 years.
Additionally, the number of violations, number of systems with violations, average number of
violations per system, and the percent of systems with violations are presented for three TCR
MCL violations (Total MCL violations, Acute MCL violations, and Monthly MCL violations)
and four Monitoring & Reporting violations (Routine: Major Monitoring & Reporting
Violations, Routine: Minor Monitoring & Reporting Violations, Repeat: Major Monitoring &
Reporting Violations, and Repeat: Minor Monitoring & Reporting Violations) in Exhibits 9-12
Exhibit 9: Average1 of Annual Numbers of Violations per Year
MCL Violation: Total IllliiSll9,878
MCL Violation: Acute 11,568
MCL Violation: Morthly MBM 8.310
- 31,112
Monitoring: Routined ajar |
and Reporting
Monitoring: Routine/Mi nor 13,151
and Reporting
Monitoring: R epestWajor ] 1,904
and Reporting
Monitoring: RepestMi nor ] 1,045
and Reporting _L
In 1997-2003, an annual average of 9,878 TCR
MCL violations were reported in SDWIS. Of
those, 84% (8,310) were Monthly MCL
violations and 16% (1,568) were Acute MCL
violations.
The vast majority (83.6%) of the monitoring
violations were Routine: Major Monitoring
(31,112), with Routine: Minor Monitoring
violations representing 8.5% of the monitoring
violations, Repeat: Major Monitoring at 5.1 %,
and Repear: Minor Monitoring at 2.8%.
Standard Deviations are as follows: 925.7 for MCL Violation: Total; 737.8 for MCL Violation: Acute; 245.2 for
MCL Violation: Monthly; 1953.9 for Monitoring and Reporting: Routine Major; 549.6 for Monitoring and
Reporting: Routine Minor; 193.1 for Monitoring and Reporting: Repeat Major; and 339.7 for Monitoring and
Reporting: Repeat Minor.
17
-------
Exhibit 10: Average1 of Annual Numbers of Systems With Violations
MCL Violation: Total
MCL Violation Acute
MCL Violation: Monthly
Monitoring: RoutineMajor
and Reporting
Monitoring: RoutineMinor
and Reporting
Monitoring: RepesiMajor
and Reporting
Monitoring: RepesiMnor
and Reporting
121A
¦ 1,179
R fififi
18,917
I
12,547
~ 1,676
~ 925
From 1997-2003, an annual average of
7,274 systems incurred a TOR MCL
violation. Of those systems with an MCL
violation, far more systems incur Monthly
MCL violations (6,688) than Acute MCL
violations (1,179).
With regards to monitoring violations,
many more systems incur Routine: Major
Monitoring violations (18,917) than other
types of monitoring violations or MCL
violations.
1 Standard Deviations are as follows: 316.6 for MCL Violation: Total; 486.2 for MCL Violation: Acute; 149.5 for
MCL Violation: Monthly; 1238.3 for Monitoring and Reporting: Routine Major; 391.0 for Monitoring and
Reporting: Routine Minor; 127.1 for Monitoring and Reporting: Repeat Major; 262.0 and for Monitoring and
Reporting: Repeat Minor.
Exhibit 11: Average' of Annual Numbers of Violations Per System
MCL Violation: Total
MCL Violation: Monthly
M onitoring: Routi ne/M ajor
and Reporting
Monitoring: Routine/Minor
and Reporting
Monitoring: RepesiMajor
and Reporting
Monitoring: R epe^jM i nor
and Reporting
1
¦ 0.059
0.187
¦ 0.009
¦¦¦0.050
1
10.019
~ 0.011
] 0.006
The average number of violations per
system per year for TCR MCL violations is
0.059 violations per year (approximately 1
violation for every 18 systems). The TCR
Monthly MCL violation rate is close to this
at 0.050 (1 violation for every 20 systems),
while the number of Acute violations per
system is lower (1 violation for every 106
systems).
The average number of Routine: Major
Monitoring violations per system is 0.187
per year.
'Standard Deviations are as follows: 0.0044 for MCL Violation: Total; 0.004 for MCL Violation: Acute; 0.0014 for
MCL Violation: Monthly: 0.0121 for Monitoring and Reporting: Routine Major; 0.0030 for Monitoring and
Reporting: Routine Minor; 0.0008 for Monitoring and Reporting: Repeat Major; and 0.0019 for Monitoring and
Reporting: Repeat Minor.
18
-------
Exhibit 12: Average1 of Annual Percentages of Systems with Violations
MCL Violation Total
MCL Violation: Acute
M C L Violation: M ontN y
M onitoring: Routi ne/M ajor
and Reporting
Monitoring: RoutineJMiror
and Reporting
Monitoring: Repesi/Major
and Reporting
Monitoring: Repe^/Minor
and Reporting
^^^^¦4.4%
10.7%
1 !4.0%
11.4%
11.5%
~ 1.0%
] 0.6%
In 1997-2003, an annual average of 4.4% of
systems incurred a TCR MCL violation. Monthly
MCL violations were incurred by 4.0% of
systems, while Acute violations were incurred
by a far smaller percent of systems at 0.7%.
1 Standard Deviations are as follows: 0.12% for MCL Violation: Total; 0.26% for MCL Violation: Acute; 0.098%
for MCL Violation: Monthly; 0.74% for Monitoring and Reporting: Routine Major; 0.21% for Monitoring and
Reporting: Routine Minor; 0.038% for Monitoring and Reporting: Repeat Major; and 0.15% for Monitoring and
Reporting: Repeat Minor.
The next three sections compare the TCR violations data across three characterizations:
system size, system type, and source water. As evidenced by the previously reported inventory
data, the number of systems can vary substantially across system size, type and source water.
Therefore, only the percent of systems with violations (also referred to as the violation rate) is
used to directly compare across categories, although the other data elements are included in the
appendices. Each section contains a graphic representation of the percent of systems with each
type of violation averaged over the period of 1997-2003, by system size, type, or source for a
visual comparison. The section also includes the results of a more formal, but basic, statistical
comparison of the data to determine if any differences among categories are statistically
significant. The methodology used to develop these results is described in Appendix K.
The following sections only present the violations rates by system size, system type, or
source. There is no attempt made to interpret the data or to posit explanations for differences
among categories. Important considerations, such as confounding among the classifications (i.e.,
the apparent relationship that one or more variables may or may not be making towards a single
observed effect) and the impact of Monitoring & Reporting frequencies and violation triggers,
could be the subject of future analyses. In addition, there may be a connection between
Monitoring & Reporting violations and MCL violations: namely, when a system fails to monitor
the water quality or report the results, MCL violations could be under-reported. We analyze this
issue to a limited extent in Exhibits X, but the impacts are not considered further.
19
-------
6. TCR Violations by System Size
This section provides an analysis of the percent of systems incurring TCR violations
categorized by system size. Exhibit 13 presents the average of annual percentage of systems
incurring MCL violations from 1997-2003, categorize by size and Exhibit 14 presents the
average of annual percentage of system incurring Monitoring & Reporting violations from 1997-
2003. Appendix A contains information by size for the number of violations, number of systems
with violations, and the average number of violations per system.
Exhibit 13: Average1 of Annual Percentages of Systems with TCR MCL Violations from
1997-2003, By System Size
(See Appendix A for Detail)
<=100
101-500
501-1,000
1,001-3,300
3,301-10,000
10,001-50,000
50,001-100,000
>100,000
Total MCL Violations
4.3%
4.5%
3.9%
4.3%
<=100
101-500
501-1,000
1,001-3,300
3,301-10,000
10,001-50,000
50,001-100,000
>100,000
Monthly MCL Violations
3.6%
4.1%
2.0%
.4%
0.0%
2.0%
4.0%
6.0%
0.0%
2.0%
4.0%
6.0%
<=100
101-500
501-1,000
1,001-3,300
3,301-10,000
10,001-50,000
50,001-100,000
>100,000
Acute MCL Violations
¦ 0.7%
H 0.8%
¦ 0.7%
¦ 0.5%
I 0.4%
¦ 0.5%
¦ 0.7%
H 0.8%
0.0%
2.0%
4.0%
6.0%
Standard Deviations are as follows:
<=100:
101-500:
501-1,000:
1,001-3,300:
3,301-10,000:
10,001-50,000:
50,001-100,000:
>100,000:
Total MCL Violations
0.13%
0.22%
0.28%
0.37%
0.48%
0.65%
1.18%
0.89%
Monthly MCL Violations
0.21% '
0.14%
0.24%
0.35%
0.49%
0.67%
0.74%
0.83%
Acute MCL Violations
0.26%
0.36%
0.29%
0.15%
0.14%
0.19%
0.76%
0.46%
20
-------
As the above exhibit illustrates, the percent of systems incurring TCR MCL violations
does vary across systems size categories, but not in a consistent pattern. For Total MCL
violations and Monthly MCL violations, the largest percent of systems incurring violations is in
the small and medium size categories: 5.1% and 4.9% for the 3,301-10,000 category and 5.6%
and 5.4% for the 10,001-50,000 category. Total MCL Violations and Monthly MCL violations
are expected to be similar, since most of the MCL violations are monthly. The smallest
percentage of systems with violations is in the largest size categories at 1.9% and 1.4% for
systems serving >100,000. The pattern is different for Acute MCL violations, with slight,
although sometimes significant, variation between 0.4% to 0.8% for all size categories. The
smallest percentage of systems with violations is in the medium size classes: 0.5% for the 1,001-
3,000 category, 0.4% for the 3,001- 10,000 category, and 0.5% for the 10,001 to 50,000
category. The largest percentage of systems with violations is in the largest size category.
Box 6.1: Statistically Significant Relationships for Total and Monthly MCL Violations
with Respect to Size
Statistically Significant Relationships for Total and Monthly MCL Violations with
Respect to Size:
• Middle size classes (3,301-50,000) have a violation rate greater than that for
other size classes.
• Larger size classes (>50,001) have a violation rate less than that for other size
classes
Statistically Significant Relationships for Acute Violations with Respect to Size:
• Very large size classes (>100,000) and Small size classes (101-500) have a
violation rate greater than that for other size classes.
• Middle size classes (1,001-10,000) have a violation rate less than that for other
size classes.
See Appendix K for discussion on Statistical Analysis of TCR Violation Data
21
-------
Exhibit 14: Average1 of Annual Percentages of Systems with TCR Monitoring & Reporting
Violations from 1997- 2003, By System Size
Routine: Major Monitoring and Reporting Violations
313.;
< = 100
101-500
501-1,000
1 J301-3.300
3,301-10,000
10 £101-50,000
50 £IU 1 -100,000
>100,000
~ 1 1 .1 %
] 7.5%
3 4.6%
3 2.0%
]1 .1%
~ 1.5%
11.0%
%
0.0%
5.0%
10.0%
15.0%
Repe.it: Major Monitoring ami Reporting Violations
<=100
101-500
501-1 £00
1 £01-3,300
3£ 01-10 £00
10 £01 -SO £00
50 £01-100 £00
>100£00
11 .1%
II .0%
10.6%
10.5%
10.6%
10.5%
11 .0%
0.0%
5.0%
'Standard Deviations are as follows:
Rorrtine: Minoi Monitoring and Reporting Violations
< = 100
101-500
501-1,000
1 £01-3,300
3301-10,000
10 £01 -50,000
50 £01-100,000
>100,000
~ 1 .1%
=11 .5%
=11 .5%
~ 4.1%
14.0%
13.5%
2 3%
11.1%
0.0% 1.0% 2.0% 3.0% 4.0%
5.0%
Repeat: Minor Monitoring and Reporting Violations
<=100
101-500
501-1,000
1 £01-3,300
3,301-10,000
10,001-50,000
50,001-100,000
>100,000
0.0% 1.0% 2.0% 3.0% 4.0% 5.0%
10.6%
10.6%
10.6%
0.7%
11.0%
11.5%
Routine: Major
MR Violations
Routine: Minor
MR Violations
Repeat: Major
MR Violations
Repeat: Minor
MR Violations
<=100:
1.18%
0.16%
0.05%
0.12%
101-500:
0.68%
0.31%
0.11%
0.19%
501-1,000:
0.55%
0.28%
0.12%
0.19%
1,001-3,300:
0.69%
0.38%
0.15%
0.19%
3.301-10,000:
0.44%
0.52%
0.12%
0.31%
10,001-50,000:
0.22%
0.89%
0.16%
0.31%
50,001-100,000:
0.76%
1.30%
0.41%
0.66%
>100,000:
0.69%
0.71%
0.74%
0.43%
As the above exhibit illustrates, average of annual percentages of systems with TCR
Monitoring & Reporting violations does vary across systems size categories and, in the cases of
Routine: Major violations and Repeat: Minor violations, shows visible trends with increasing
population. For Routine: Major violations, the largest percent of systems incurring violations is
in the smallest size category (<100) with 13.5%, or nearly one in 7 systems, incurring a violation.
As shown in Appendix G-l, the trend for systems serving <100 has been relatively steady over
time, with 13.4% (13,343/99,575) having Routine: Major violations in 1997 and 14.0%
22
-------
(12,521/89,436) in 2003, with a low of 11.1% (10,970/98,829) in 1998 and a high of 14.9%
(13,363/96,396) in 1999.
The percent of systems incurring Routine: Major violations declines as the size category
increases with only an average of 1.0% of the largest systems incurring violations (with a slight
exception between 50,001-100,000). The trend in Routine: Major violations for the largest
systems has been decreasing, from 1.7% (6/353) in 1997 to 0.3% (1/333) in 2003. For Routine:
Minor violations, the highest percent of systems incurring violations is in the mid-range
categories at 4.1% of systems 1,001-3,000 and 4.0% of systems 3,001-10,000.
Box 6.2: Statistically Significant Relationships for Total Monitoring & Reporting
Violations with Respect to Size
Statistically Significant Relationships for Monitoring & Reporting Violations with Respect to
Size:
Routine: Major and Repeat: Major violations:
• Smallest size class (<100) has a violation rate greater than other size classes for
Routine: Major Monitoring & Reporting Violations and slightly greater for Repeat-
Major Monitoring & Reporting Violations..
• Middle and large size classes (>501) have a violation rate less than other size
classes (except the largest size class for Repeat: Minor violations).
Routine: Minor and Repeat: Minor violations:
• Smallest size class (<100) has a violation rate less than other size classes.
See Appendix K for discussion on Statistical Analysis of TCR Violation Data
The trend of violations as population size increases is inconsistent for Repeat: Major
violations, but consistent for Repeat: Minor violations. For Repeat: Major violations, the percent
of systems with violations is highest in the smallest two categories (1.1% for <100 and 1.0% for
101-500) and the largest category (1.0% for >100,000). The smallest percent of systems
incurring Repeat: Major violations is in the middle categories. For Repeat: Minor violations, the
highest percent of systems with violations is found in the largest category (1.5% in the >100,000
category). The percent of systems incurring Repeat: Minor violations declines as the size
category decreases with only 0.5% of the smallest systems incurring violations.
23
-------
7. TCR Violations by System Type
This section provides an analysis of the percent of systems incurring TCR violations
categorized by type of system. Exhibit 15 presents the average of annual percentages of systems
with TCR MCL violations from 1997-2003 by type of system and Exhibit 16 presents the
average of annual percentages of systems with TCR Monitoring & Reporting violations by type
of system. Appendix B contains information by type of system for the number of violations,
number of systems with violations, and the average number of violations per system from 1997
to 2003.
Exhibit 15: Average1 of Annual Percentages of Systems with TCR MCL Violations from
1997- 2003, By System Type
Total MCL Violations
Monthly MCL Violations
cws
NTNCWS
TNCWS
0.0%
2.0%
5.2%
4.4%
3.9%
4.0%
6.0%
CWS
NTNCWS
TNCWS
0.0%
4.8%
4.0%
3.5%
2.0%
4.0%
6.0%
Acute MCL Violations
CWS ^¦o.73%
NTNCWS ^¦0.74%
TNCWS
0.68%
0.0%
2.0%
4.0%
6.0%
Standard Deviations are as follows:
CWS:
NTNCWS:
TNCWS:
Total MCL Violations
0.51%
0.21%
0.22%
Monthly MCL Violations
0.43% '
0.21%
0.28%
Acute MCL Violations
0.28%
0.24%
0.31%
The percent of systems with Acute and Monthly MCL violations is similar across
the three types of systems (CWS, NTNCWS, TNCWS) with small (but in some cases,
24
-------
significant) differences. Acute MCL violations ranged from 0.68 - 0.74%, with the lowest
percent of systems occurring in the TNCWS category. This difference, however, is not
statistically significant for Acute MCL violations. For Monthly MCL violations, the TNCWS
category has the lowest percent of systems with violations at 3.5%, with CWSs at 4.8% and
NTNCWSs at 4.0%.
Box 7.1: Statistically Significant Relationships for TCR MCL Violations from 1997- 2003,
By System Type
Statistically Significant Relationships for Total and Monthly MCL Violations with Respect
to Type:
¦ Cl/l/Ss have a violation rate greater than other system types.
m TNCWSs have a violation rate less than other system types.
See Appendix K for discussion on Statistical Analysis of TCR Violation Data
25
-------
Exhibit 16: Average1 of Annual Percentages of Systems with TCR Monitoring & Reporting
Violations from 1997- 2003, By System Type
Routine: Major Monitoring and Reporting Violations
Routine: Minoi Monitoring and Repotting Violations
cws
NTNCWS
TNCWS
7.9%
10.6%
I 3.6
%
0.0%
5.0%
10.0%
15.0%
CWE
NTNCWS
TNCWS
]2.8%
1.0%
] 0.9%
0.0% 1.0% 2.0% 3.0% 4.0% 5.0%
Repeat: Major Monitoring and Reporting Violations
Repeat: Minoi Monitoiing and Repotting Violations
CWS
NTNCWS
TNCWS
1.1%
0.7%
1.0%
0.0% 1.0% 2.0% 3.0% 4.0% 5.0%
CWS
NTNCWS
TNCWS
] 0.8%
0.5%
I 0.5%
0.0% 1.0% 2.0% 3.0% 4.0% 5.0%
'Standard Deviations are as follows:
Routine: Major Routine: Minor Repeat: Major Repeat: Minor
MR Violations MR Violations MR Violations MR Violations
CWS: 0.93% 0.46% 0.24% 0.24%
NTNCWS: 1.5% 0.15% 0.090% 0.11%
TNCWS: 1.6% 0.11% 0.058% 0.11%
The percent of systems with Routine: Major Monitoring & Reporting violations is greater
for TNCWSs (13.6%) than for CWSs (7.9%) or NTNCWSs (10.6%). The percent of systems
with Routine: Minor violations is much lower for all types of systems than Routine: Major, with
2.8% of CWSs having violations and 1.0% and 0.9% of NTNCWSs and TNCWSs, respectively.
A relatively small percentage of systems incur a Repeat Monitoring & Reporting
violation: on average, between 0.7% and 1.1% incur Repeat: Major violations and between 0.5%
and 0.8% incur Repeat: Minor violations. A slightly greater percent of all systems types incur
Repeat: Major violations than Repeat: Minor violations.
Page 26
-------
Box 7.2: Statistically Significant Relationships for TCR Monitoring & Reporting
Violations from 1997- 2003, By System Type
Statistically Significant Relationships for Monitoring & Reporting Violations with Respect to
Type:
Routine: Major violations:
¦ Cl/l/Ss have a violation rate less than other system types.
m TNCWSs have a violation rate greater than other system types.
Routine: Minor and Repeat: Minor violations:
Cl/I/S have a violation rate greater than other system types.
NTNCWSs and TNCWSs have a violation rate less than Cl/l/Ss.
See Appendix K for discussion on Statistical Analysis of TCR Violation Data
Page 27
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8. Analysis of TCR Violations By Source Water
The following section provides an analysis of TCR violations broken out by source water
used. Exhibit 17 presents the average of annual percentages of systems with TCR MCL
violations from 1997-2003, by source water, and Exhibit 18 presents the average of annual
percentages of systems with TCR Monitoring & Reporting violations, by source water. Appendix
C contains information by source water for the number of violations, number of systems with
violations, and the average number of violations per system.
Exhibit 17: Average1 of Annual Percentages of Systems with TCR MCL Violations from
1997- 2003, By Source Water
Total MCL Violations
GU
GW
SW
10.6%
4.4%
3.5%
0.0% 2.0% 4.0% 6.0% 8.0% 10.0% 12.0%
Monthly MCL Violations
GU
GW
SW
| M 8.0%
4.1 %
27%
0.0% 2.0% 4.0% 6.0% 8.0% 10.0% 12.0%
Acute MCL Violations
GU
¦ 4.9%
| 0.6%
B1.3%
0.0% 2.0% 4.0% 6.0% 8.0% 10.0% 12.0%
Standard Deviations are as follows:
GU:
GW:
SW:
Total MCL Violations
5.8%
0.13%
3.5%
Monthly MCL Violations
4.1%
0.11%
0.43%
Acute MCL Violations
3.7%
0.25%
0.51%
Page 28
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The highest percent of systems with MCL violations is among systems that use
Groundwater Under the Direct Influence of Surface Water (GU)12. This relationship holds true
across all of the violations types, including 4.9% of GU systems incurring Acute MCL violations
and 8.0% incurring Monthly MCL violations. The percent of systems incurring Acute MCL
violations is 0.6% for GW and 1.3% for SW systems, while a greater percent of groundwater
systems incur monthly MCL violations (4.1%) than surface water systems (2.7%), on average
from 1997-2003. As displayed in Appendix E-3, in each year from 1997-2003, SW and GU have
consistently higher Acute violations rates than GW systems, and this relationship is statistically
significant.
Box 8.1: Statistically Significant Relationships for TCR MCL Violations from 1997- 2003,
By Source Type
Statistically Significant Relationships for Total and Monthly MCL Violations with Respect to
Source:
m Systems using GU have a violation rate greater than other water sources.
m Systems using SI/1/have a violation rate less than other water sources.
Statistically Significant Relationships for Acute MCL Violations with Respect to Source:
m Systems using GU have a violation rate greater than GW and SI/1/ systems.
m Systems using SI/1/ have a violation rate greater than GW systems.
m Systems using GW have a violation rate less than other water sources.
See Appendix K for discussion on Statistical Analysis of TCR Violation Data
12
It is important to note that the total number of violations attributable to GU systems is quite low because
of the relatively small number of systems in this category.
Page 29
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Exhibit 18: Average5 of Annual Percentages of Systems with TCR Monitoring & Reporting
Violations from 1997- 2003, By Source Water
Routine: Majoi Monitoi inij iind Rtpoitiiuj Violiitioiiis
Routine: Minor Monitoring and Reporting Violations
27.6%
11.7%
7.1%
10.0%
20.0%
30.0%
8.0%
Repeat: Major Monitoi ing and Reporting Violations
GU
~ 4.6%
-
GW
~ 1.0%
SW
10.7%
I
I 1
0.0%
2.0%
4.0%
6.0%
8.0%
Repeat: Minor Monitoring and Repotting Violations
GU
GW
SW
J 5.2%
|p .5%
10.6%
0.0% 2.0% 4.0% 6.0%
3.0%
'Standard Deviations are as follows:
GU:
GW:
SW:
Routine: Major Routine: Minor Repeat: Major Repeat: Minor
MR Violations MR Violations MR Violations MR Violations
11.6% 2.8% 2.1% 4.2%
0.81% 0.18% 0.038% 0.13%
0.74% 0.67% 0.14% 0.27%
A larger fraction of systems using groundwater under the influence incur all four types of
Monitoring & Reporting violations than systems using either surface water or groundwater
(Routine: Major at 27.6%; Routine: Minor at 7.2%, Repeat: Major at 4.6%; and Repeat: Minor at
5.2%). On average, a larger fraction of systems using groundwater (11.7%) incur Routine: Major
violations than surface water systems (7.1%). The percent of systems incurring Repeat: Major
violations is higher for those using groundwater (1.0%) than surface water (0.7%), although a
slightly greater fraction of surface water systems (0.6%) incur Routine: Minor violations than
groundwater (0.5%).
Page 30
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Box 8.2: Statistically Significant Relationships for TCR Monitoring & Reporting
Violations from 1997- 2003, By Source Type
Statistically Significant Relationships for Monitoring & Reporting Violations with Respect to
Source:
Routine Major and Repeat Major violations:
m GU systems have a violation rate greater than other water sources.
SI/1/ systems have a violation rate less than other water sources.
Routine Minor and Repeat Minor violations:
GU systems have a violation rate greater than other water sources.
GW systems have a violation rate less than other water sources for Routine Minor.
Page 31
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9. Analysis of Repeat Violators
This section describes analyses conducted to assess the degree to which systems incur
violations repeatedly over a number of years. Basically, the next set of exhibits present, for
systems that had at least 1 TCR violation over the 1997 to 2003, the percentage of systems that
incurred a violation in only 1 year, 2 years, and up to all seven years. This means at least one
violation in any one of the years between 1997 to 2003.
Exhibit 19: Percent of Systems With Violations In A Given Number of Years -
All TCR Violations
Percent of Systems By the Number of Years in Which At Least 1 TCR Violation Is Incurred
50.1%
50.0%
o 45.0%
2 40.0%
t/> 35.0%
TO
J
5 30.0%
£
i 25.0%
I 20.0%
15.0%
10.0%
5.0%
0.0%
Number of Systems With Any TCR Violation: 96,389
24.7%
'l
1
6.7%
¦
3.8%
| | 14% 0.8%
Number of Years In Which A TCR Violation Is Incurred
During the period of 1997 to 2003, 96,389 systems had at least 1 TCR violation of any
kind, out of a possible universe of systems ranging in number from 170,679 to 161,201.
Roughly 55% to 60% of all systems had at least 1 TCR violation during 1997 to 2003. Of these
systems, about half (50.1%) incurred at least 1 violation in only 1 year, with another 24.7%
incurring at least 1 violation in 2 of the 7 years. A small fraction of systems (0.8%) incurred at
least 1 violation in all 7 years and 1.4% incurred at least 1 violation in 6 of 7 years.
Page 32
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Exhibit 20: Percent of Systems With Violations In A Given Number of Years -
Acute MCL Violations
.2
§>
I
-------
During the period of 1997 to 2003, 33,586 systems had at least 1 Monthly MCL
violation. Of those, the vast majority (72.6%) incurred at least 1 Monthly MCL violation in only
1 of the 7 years. A small fraction incurred at least 1 Monthly MCL violation in all 7 years (0.1%
or 21 systems) with another 0.2% (52 systems) incurring at least 1 Monthly MCL violation in 6
of 7 years. Approximately 8.3% (2,793 systems) appear to have chronic problems as indicated
by incurring at least 1 Monthly MCL violation is 3 or more years out of 7.
Exhibit 22: Percent of Systems With Violations In A Given Number of Years -
Monitoring & Reporting Violations
60%
o 50%
>
ft
08
40%
- 30%
-------
An additional set of analyses was conducted to assess whether certain types of violations
were more likely to co-occur. One analysis quantified the extent that systems with an Acute
MCL violation also had a Monthly MCL violation. Exhibit 23 displays the percent of
systems with an Acute MCL violation that also had a Monthly MCL violation within the
same fiscal year.
Exhibit 23: Percent of Systems with Acute Violations that Also Have a Monthly Violation
in the Same Year
Percent of Systems with Acute Violation That Also Have
a Monthly Violation in the Same Year
70%
60%
iQ.5%
12.7%
50%
.6%
40%
30%
20%
10%
0%
1997
1998
1999
2000
2001
2002
2003
Roughly half of the systems that have an Acute MCL violation also have at least 1
Monthly MCL violation in the same fiscal year. The data does not show trend over time, with a
high of 59.5% in 1998, a low of 41.6% in 2000, and 48.0% in the most recent year (2003).
To attempt to determine the extent that systems may be incurring a Monitoring &
Reporting violation to avoid an MCL violation, the following analysis compares the rate of
previous MCL violations in systems with and without Monitoring & Reporting violations. The
analysis first separates out the universe of systems that had any Monitoring violation13 in 2003:
21,282 systems had at least 1 Monitoring & Reporting violation (of any type) in 2003 and
139,919 did not have Monitoring & Reporting violation in 2003. The analysis then looked at
whether a system had at least 1 MCL violation in the previous year (2002). Exhibit 24
summarizes the results of the analysis.
13 The analysis does not distinguish between the four Monitoring & Reporting violations.
Page 35
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Exhibit 24: How do subsequent monitoring violation rates compare among systems with
previous MCL violations?
Number of
ms
Number of Systems With
MCL in Previous Year
Systems with M&R Violation in 2003
21,282
1,460
6.9%
Systems w/o M&R in 2003
139,919
5,580
4.0%
Total
161,201
7,040
4.4%
Of the 21,282 systems that incurred at least 1 Monitoring & Reporting violation in 2003,
1,460 (6.9%) had at least 1 MCL violation in the previous year (2002). Of the 139,919 systems
that did not have a Monitoring & Reporting violation in 2003, 5,580 had an MCL violation in the
previous year, a rate of 4.0%. Based on this analysis, systems with at least 1 Monitoring &
Reporting violation in 2003 had a higher rate of previous MCL violation in 2002, 6.9% vs. 4.0%.
Expressing it another way, systems with a Monitoring & Reporting violation in 2003 made up
13.2%) of all systems, but had 20.7% of the MCL violations in the previous year. These data
show that it is 1.72 times as likely to observe a Monitoring & Reporting violation in a system
that had an MCL violation the previous year than in a system without an MCL violation in the
previous year with the 95% confidence interval of the odds ratio as follows:
The difference in rates of previous MCL violation may indicate the extent to which
systems could be incurring a Monitoring & Reporting violation instead of an MCL violation. It
is important to note that the vast majority (93%) of systems with a Monitoring & Reporting
violation in 2003 did not have an MCL violation in the previous year.
/ MCL violation '
[1.638,1.801]
No MCL violation y
Page 36
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10. Analysis of TCR Violations Over Time
This section provides analysis of percent of systems with TCR violations and the number
of systems with TCR violations each year over the period of 1997 to 2003. Exhibit 25 contains
information on the percent of systems incurring MCL violations over the time period and Exhibit
26 presents the number of systems incurring MCL violations. Exhibit 27 contains information on
the percent of systems incurring Monitoring & Reporting violations over the time period and
Exhibit 28 presents the number of systems incurring Monitoring & Reporting violations.
Appendices D-I contain information broken down by size, type, and source water over time.
Exhibit 25: Percent of Systems Incurring TCR MCL Violations from 1997 to 2003
(/)
E
0)
>
w
-------
Exhibit 26: Number of Systems Incurring TCR MCL Violations from 1997 to 2003
E
-3
>
o
-Q
E
3
9,000
8,000
7,000
6,000
5,000
4,000
3,000
2,000
l,UUU -
n
•
•
—•
1997
1998
1999
2000
2001
2002
2003
-¦-MCL
7,728
7,664
7,376
6,972
7,035
7,040
7,102
m Acute MCL
1,874
1,772
1,362
844
857
794
748
A Monthly MCL
6,780
6,947
6,683
6,479
6,630
6,584
6,713
Note: The total number of systems has decreased overtime.
Over the period of 1997 to 2003, number of systems experiencing an Acute MCL violation
has steadily declined in each year, with the number of systems with an Acute MCL in 2003 less
than half of the number of systems in 1997. The number of systems incurring Monthly MCL
violations has remained relatively steady, with slight year to year changes (+ or - 4%).
Page 38
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Exhibit 27: Percent of Systems with TCR Monitoring & Reporting Violations from 1997 to
2003
(0
E
<
w
-------
Exhibit 28: Number of Systems with TCR Monitoring & Reporting Violations from 1997 to
2003
25,000 n
& 15,000 -
(/)
O
l.
Ja 10,000 -
E
3
5,000 -
n
* ' T * * 1 *
1997
1998
1999
2000
2001
2002
2003
» Routine: Major
20,201
16,912
20,661
18,839
18,942
18,356
18,506
—¦—Routine: Minor
3,042
3,057
2,695
2,454
2,217
2,124
2,241
A Repeat: Major
1,914
1,770
1,662
1,649
1,593
1,541
1,602
)( Repeat: Minor
1,266
1,295
755
979
680
795
703
Note: The total number of systems has decreased overtime.
The number of systems incurring Routine: Major Monitoring & Reporting violations did
not change to a great extent from 1997 to 2003, but did decrease substantially in 1998 and
rebound in 1999 before stabilizing. The number of systems with Routine: Minor Monitoring &
Reporting violations decreased from 1997 to 2003. The number of systems with Repeat: Major
Monitoring & Reporting violations decreased slightly over the time period, while the number
with Repeat: Minor Monitoring & Reporting decreased overall, although with increases and
decreases from year to year.
An observed overall tendency does not necessarily represent the tendency for each
specific category of systems. For example, the percent of systems serving fewer than 100
incurring an Acute MCL violation is observed to decrease over time, while the percent of
systems serving greater than 100,000 incurring an Acute MCL violation seems to remain steady
between 1997 and 2003.
When an overall tendency was not observed, it was still possible that specific categories of
systems may have observable tendencies. For example, the percent of GU and SW systems with
a monthly MCL violation decreased, but the percent of GW systems with a monthly MCL
violation increased slightly. In this case, the two opposing trends negate one another, resulting in
Page 40
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an net result of no overall change. To examine how well overall trends represent the individual
trends for each category of systems, the following table summarizes overall trends in comparison
with individual trends for each TCR violation type. This table does not reflect changes from
year to year, which can show some variation. Especially for categories with few systems, very
small differences in the number of violations may result in wider and inconsistent variations in
the rate of violations from year to year. These year to year variations can be observed from the
detailed data in the appendices.
Page 41
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Exhibit 29: Observed Overall Change in Violation Rate from 1997 to 2003
(+ indicates an increase, - indicates a decrease)
TCR MCL Violations
TCR Monitoring & Reporting Violations
MCL:
Total
MCL:
Acute
MCL:
Monthly
Routine:
Major
Routine:
Minor
Repeat:
Major
Repeat:
Minor
Overall Trend (Change
from 1997 to 2003)
-
-
+
-
-
-
-
By System Size
<=100
+
-
+
+
-
+
-
101-500
-
-
-
-
-
-
-
501-1,000
-
-
-
-
-
-
-
1,001-3,300
-
-
-
-
-
-
-
3,301-10,000
-
-
-
-
-
+
-
10,001-50,000
-
-
-
-
-
-
-
50,001-100,000
-
-
-
-
-
-
-
>100,000
-
-
-
-
-
+
-
By System Type
cws
-
-
-
-
-
-
-
NTNCWS
+
-
+
-
-
+
-
TNCWS
+
-
+
+
-
+
-
By Source Water
GU
-
-
-
-
-
-
-
GW
+
-
+
-
-
-
-
SW
-
-
-
-
-
-
-
Acute MCL Violations:
The percent of systems experiencing an Acute MCL violation decreased by over half
from 1.1% in 1997 to 0.5% in 2003. When examining individual trends for each size class, the
percent of systems with violations decreased over time, except for the largest size class. In the
largest size class (>100,000), Acute MCL violations remained relatively steady (1.2% in 1997
and 1.1% in 2003). Because of the relatively small number of systems in this size class and the
relatively infrequent incurrence of Acute MCL violations, very small differences in the number
of violations from year to year may result in wider and inconsistent variations in the rate of
violations. The percent of systems with violations for all system types and water sources
decreased with time.
Monthly MCL Violations:
The fraction of systems incurring Monthly MCL violations has increased, although very
slightly from 4.0% to 4.2%. Not all types of systems follow this slight increasing trend. For
example, the percent of medium and large systems (501-50,000 and >100,000) with violations
Page 42
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showed an overall decrease over time. Monthly MCL violations decreased for CWS whereas
violations increased for NTNCWS and TNCWS. The percent of systems with monthly MCL
violations decreased for GU and SW, but increased for GW.
Routine: Major Monitoring & Reporting
The percent of systems incurring routine major violations did not change to a great extent
from 1997 to 2003 (11.8% vs. 11.5%). The percent of systems with violations decreased for all
size classes in 1998, except for the (50,001-100,000) system, which followed the opposite
pattern by substantially increasing in 1998 and decreasing in 1999. There was an overall
decrease in the percent of systems with routine major violations for moderately small and
medium sized systems (101-3,330) and for the two largest system categories (>50,001). The
percent of CWS and NTNCWS systems with routine major violations decreased while the
percent of TNCWS systems with violations increased. The percent of GU and SW systems with
violations decreased substantially from 1997-2003, with the percent of GW systems also
decreasing but by a small amount.
Routine: Minor Monitoring & Reporting
The percent of systems with Routine: Minor Monitoring & Reporting violations
significantly decreased from 1997 (1.8%) to 2003 (1.4%). All categories of systems follow this
overall decreasing trend between 1997 and 2003 (although the trend does not necessarily hold
true for every year over this period).
Repeat: Major Monitoring & Reporting
The percent of systems with Repeat: Major Monitoring & Reporting violations remained
steady over the time period. There was a slight decrease for moderately small-medium systems
(101-3,330) and the largest systems (>100,000). The percent of systems with violations
decreased for CWS and slightly increased for TNCWS. The percent of GU and SW systems with
violations decreased. The percent of GW systems also decreased, but only by a small amount.
Repeat: Minor Monitoring & Reporting
The percent of systems with Repeat: Minor Monitoring & Reporting violations
significantly decreased overall, with an increase in 1998. All categories of systems followed this
overall decrease, although some system categories decreased more than others. Largest decreases
were seen in CWS, GU, 50,001-100,000 and 3,301-10,000 categories.
Page 43
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11. More Recent TCR Violation Data
The SDWIS data used for the analyses detailed in this paper originated from a January
2004 data query and contained information on violations through Fiscal Year 2003. Additional
data is now available that covers Fiscal Year 2004 and 2005. The following exhibits display the
overall violation rates for MCL, Monthly, Acute and Monitoring & Reporting violations for FY
2004 and 2005.
Exhibit 30: Recent Observations in TCR MCL Violations Data (FY 2004 & 2005)
Percent of Systems With TCR MCL Violation
4.6%
E
-3
>
4.5%
4.4%
4.3%
c 4.2%
o
2
o
o- 4.1%
4.0% -
3.9%
1997
-MCL 4.5%
1998
4.5%
1999
4.4%
2000
4.2%
2001
4.3%
2002
4.36%
2003 2004
4.41% 4.47%
2005
4.50%
The percent of systems with a TCR MCL violation continued a slight upward trend
during 2004 and 2005 (from 4.41% in 2003 to 4.47% in 2004 to 4.50% in 2005).
Page 44
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Exhibit 31: Recent Observations in TCR Monitoring & Reporting Violations Data (FY
2004 & 2005)
Percent of Systems With Any TCR Monitoring & Reporting Violation
14.5%
14.0%
13.5%
13.0%
12.5%
12.0%
11.5%
11.0%
¦Any Monitoring
§
c
2
o
Q.
,o
1997 1998
14.1% 12.3%
1999 2000 2001 2002
14.2% 13.1% 13.2% 13.1%
2003
13.2%
2004
12.5%
2005
13.2%
The percent of systems with TCR Monitoring & Reporting violations decreased from
2003 to 2004 (13.2% to 12.5%) and then rebounded back to 2003 levels in 2005.
Page 45
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12. Analysis of TCR Violations by Treatment Technology
SDWIS contains a data field that identifies the treatment technology used at a system,
including whether a disinfection treatment is applied. As part of this paper, consideration was
given to comparing TCR violation rates of disinfecting systems with those where no disinfection
treatment(s) were applied. The treatment data was not consistently reported or of adequate
quality for this analysis.
Page 46
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13. Analysis of TCR Violations by Season
An analysis of variations in TCR violations across seasons was conducted. To ensure
consistency across this report, analysis of seasonal variability has been conducted on data from
FY 1997 - FY 2003. Analysis has also been limited to Acute MCL violations as these pose the
greatest health risk. Exhibit 32 depicts the total number of Acute MCL Violations reported by
month of the year (for All PWSs).
Exhibit 32: Total Number of Acute MCL Violations By Month, 1997-2003
Month
Acute MCL
January
1,160
February
495
March
383
April
1,515
May
559
June
758
July
2,800
August
947
September
744
October
2,152
November
603
December
520
It can be noted that there are high numbers of violations in months January, April, July,
and October. These spikes are attributed to PWSs that are on quarterly or annual monitoring &
reporting. However, there is no EPA requirement pertaining to which month a quarter must
commence with (e.g. a quarter in some state may commence in February even though most states
appear to use the standard January, April, July, and October as the beginning months.
While it does appear that in the warmer months there are more Acute MCL violations
reported than in the cooler months, sufficient analysis has not been completed to confirm these
conclusions. For example, during the summer months many "vacation" communities increase the
number of samples required (and may increase Monitoring & Reporting to monthly rather than
quarterly) to account for those seasonal fluctuations; increasing sampling frequency and number
of samples increase the "opportunity" to have a TCR Acute MCL Violation. So the fact that
there are more violations reported may be attributed to the warmer weather which creates better
opportunity for those violations to occur, or it may be attributed to more frequent Monitoring &
Reporting which may create more opportunities for the violations to be discovered.
Exhibit 33 categorized these violations by PWS Type.
Page 47
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Exhibit 33: Number of Acute MCL Violations By Month and System Type, 1997-2003
Month
cws
NTNCWS
TNCWS
January
398
128
634
February
373
47
75
March
272
37
74
April
313
155
1,047
May
345
50
164
June
415
56
287
July
632
310
1,857
August
595
85
267
September
465
76
203
October
616
287
1,248
November
438
60
105
December
357
65
98
Looking exclusively at CWSs, and not including the months of January, April, July, and
October (because of the mix of Quarterly and Monthly Monitoring & Reporting variability); it
appears that in the warmest months the greatest number of violations are incurred, with August
and September having the greatest number of Acute MCL violations reported.
Exhibit 34 provides information on the percent of violations that occur with the months
grouped into four seasons: Winter includes December, January, and February; Spring includes
March, April, and May; Summer includes June, July, and August; and Fall includes September,
October, and December.
Exhibit 34: Percent of Acute MCL Violations By Season and System Type, 1997-2003
Season
CWS
NTNCWS
TNCWS
Winter (Dec, Jan, Feb)
21.6%
17.7%
13.3%
Spring (Mar, Apr, May)
17.8%
17.8%
21.2%
Summer (Jun, Jul, Aug)
31.5%
33.3%
39.8%
Fall (Sep, Oct, Nov)
29.1%
31.2%
25.7%
For all types of systems, the greatest percentage of Acute MCL violations occur during
the Summer season. The second most violations occur in the Fall, with only a few percentage
points difference between Summer and Fall for CWSs and NTNCWSs, with a larger difference
for TNCWSs. For CWSs, the season with the lowest percent of violations is Spring, while the
Page 48
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season with the lowest percent of violations is Winter for NTNCWSs and TNCWSs. With
regards to TNCWSs, the high occurrence of violations in the Summer season may be related to
increased use of facilities and increased frequency of testing during this season.
Page 49
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14. Analysis of TCR Violations Associated with Outbreak Events
Another question of interest is whether systems that experience reported waterborne
disease outbreaks also experience TCR violations. The analysis of this question is limited by the
relatively small number of waterborne disease outbreaks and, more importantly, the inability to
determine the public water system involved in an outbreak given currently available information
on the outbreaks. Annual published reports on waterborne disease outbreaks include only the
State in which the outbreak occurred, but do not identify the town or water system (see for
example CDC, 2002). Without this information, we are unable to match the outbreak incidence
with corresponding TCR violations data for all but a handful of outbreaks and systems.
Through secondary sources such as incidence investigation reports and media reports, we
were able to identify the public water systems associated with 10 waterborne disease outbreaks -
4 related to distribution system causes and 6 related to other causes (such as source water
contamination or treatment failure). Exhibit 35 presents a summary of the outbreaks and the TCR
violations for those public water systems. None of the 4 systems with a distribution system
outbreak had a TCR MCL violation around the time of the outbreak. One of the systems does not
have any reported TCR violations; one has only minor reporting violations (although several of
them); one has a bacteria violation pre-dating the TCR; and one system has 2 consecutive
Monthly MCL violations and a major Monitoring & Reporting violation several years after the
outbreak. It is important to note that it is uncertain when and where these systems take their total
coliform samples. Sampling may have taken place in areas of the distribution system that weren't
impacted by a contamination event.
A further discussion of the detection of total coliforms during outbreak investigations can
be found in the paper: Causes of Total Coliform-Positive Samples and Contamination Events in
Distribution Systems.
Page 50
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15. TCR Sanitary Survey Violations
Another type of violation under the TCR is a violation associated with the failure to
conduct the required sanitary survey. There is little data in SDWIS on Sanitary Survey TCR
violations (type 27). The data has only been reported in FY 2003 and only by a few (13) states,
totaling 90 Sanitary Survey violations. Moreover, some PWS have many TCR Sanitary Survey
Violations during the same year, thus raising further questions about the reliability,
representativeness, and value of the data (Exhibit 36). Therefore, this type of violation will not
be addressed further in this paper.
Exhibit 36: TCR Sanitary Survey Violations, 2003
Number of
Violations Per
Number of
System
Systems
1
33
2
15
3
2
4
1
7
1
10
1
Page 52
-------
16. Small System Issues
In general, small systems incur the greatest number of all types of violations, largely
because there are a greater number of small systems. As a percent of systems, however, small
systems do not incur MCL violations more frequently than other systems. In fact, the greatest
frequency seems to be in large systems for Acute MCL violations and medium systems for
Monthly MCL violations.
By contrast, small systems incur Monitoring & Reporting violations at a much greater
frequency. Small systems incur the most Routine: Major Monitoring & Reporting violations,
both in terms of the total number of violations and the percent of systems incurring violations.
For example, in 2003, systems in the smallest size category (<=100) account for 67% of these
violations but only comprise 56% of systems. Close to 1 in 7 (14%) of systems in the smallest
size category incur Routine: Major Monitoring & Reporting violations, by far the highest
frequency for any of the violations and size categories. In the next smallest size category (101-
500), 10.8%) (1 in 10) systems incur Routine: Major Monitoring & Reporting violations. In
contrast, only 1.5% of the systems in the 50,001-100,000 incur these violations. With respect to
the Routine: Major Monitoring & Reporting violations, there is a relatively consistent trend
across the system size categories of a greater frequency of violation for smaller system sizes.
See Appendices G - J for numbers and frequencies of Monitoring and Reporting Violations.
Page 53
-------
17. Summary
This paper presents data on the number of systems with the different types of TCR
violations, the number of TCR violations, the average number of TCR violations per system, and
the percent of systems with TCR violations for the time period of 1997 to 2003. Overall,
Routine: Major Monitoring & Reporting violations occur the most frequently by far - with one
in every 9 systems (11.5%) incurring a Routine: Major Monitoring & Reporting violation in
2003. By contrast, only 4.2% of systems incurred a Monthly MCL violation and only 0.5%
incurred an Acute MCL violation in 2003. The paper then compares the percent of systems with
violations across system size categories, systems types, and source waters, and over time.
The data on TCR violations presented in this paper can serve as a foundation for further
analysis and research. For example, while this paper presents comparisons of violations across
system sizes, categories, and sources, no attempt is made to explain reasons for any differences.
Next steps could include research on the impact of factors such as water quality, system
performance, and Monitoring & Reporting practices to explain the implications of differences in
violation rates.
Page 54
-------
Exhibit 37: Summary of Statistically Significant Relationships
TCR Total and Monthly MCL Violations
•
•
•
•
•
Middle size classes (3,301-50,000) have a violation rate greater than other size classes.
Larger size classes (>50,001) have a violation rate less than other size classes.
CWSs have a violation rate greater than other system types.
TNCWSs have a violation rate less than other system types.
Systems using SW have a violation rate less than other water sources.
TCR Acute MCL Violations
•
•
•
•
Smaller size classes (101-500) have a violation rate greater than other size classes.
Middle size classes (1,001-10,000) have a violation rate less than other size classes.
Systems using GU and SWhave a violation rate greater than other water sources.
Systems using GW have a violation rate less than other water sources.
Routine: Major Monitoring & Reporting Violations
•
•
•
•
•
•
Smallest size class (<100) has a violation rate greater than other size classes.
Middle and large size classes (>501) have a violation rate less than other size classes.
CWSs have a violation rate less than other system types.
TNCWSs have a violation rate greater than other system types.
GU systems have a violation rate greater than SW sources.
SW systems have a violation rate less than other water sources.
Routine: Minor Monitoring & Reporting Violations
•
•
•
•
Smallest size class (<100) has a violation rate less than other size classes.
CWS have a violation rate greater than other system types. .
GU systems have a violation rate greater than other water sources.
GW systems have a violation rate less than other water sources.
Repeat: Major Monitoring & Reporting Violations
•
•
•
•
Smallest size class (<100) has a violation rate greater than other size classes.
Middle and large size classes (>501) have a violation rate less than other size classes.
GU systems have a violation rate greater than other water sources.
SW systems have a violation rate less than other water sources.
Repeat: Minor Monitoring & Reporting Violations
•
•
•
•
Smallest size class (<100) has a violation rate less than other size classes.
CWS have a violation rate greater than other system types.
GU systems have a violation rate greater than other water sources.
GW systems have a violation rate less than other water sources.
Page 55
-------
REFERENCES
Clark, et al., A Waterborne Salmonella tyyhimurium Outbreak in Gideon, Missouri: Results from
a Field Investigation, International Journal of Environmental Health Research, 1996, 6: 187-193.
Federal Register 54 FR 27544-27568
Federal Register 68 FR 19030
Federal Register 68 FR 42907
Haupt, Thomas, Gastrointestinal Illness at Roncalli High School, Manitowoc, WI, September
1995, Communicable Disease Epidemiology Unit, Memorandum dated 7/24/96.
Missouri Division of Health, Water-borne Gastrointestinal Illness in Callaway County, 1984.
Sterling, et al., A Public Health Laboratory's Handling of a Parasitic Outbreak, Tennessee
Department of Health, Nashville, TN, 1994.
U.S. Environmental Protection Agency, June 2001, Office of Water, A Small Systems Guide to
the Total Coliform Rule: Monitoring & Reporting Drinking Water to Protect Public Health, EPA
816-R-02-017A.
U.S. Environmental Protection Agency, February 2002, Office of Water, Drinking Water
Academy: Total Coliform Rule.
U.S. Environmental Protection Agency, November 2001, Office of Water, Total Coliform Rule:
A Quick Reference Guide, EPA 816-F-01-035.
U.S. Environmental Protection Agency, October 1998, Office of Water, Information Available
from the Safe Drinking Water Information System, EPA 816-F-98-006.
U.S. Environmental Protection Agency, March 2004, Office of Water, Drinking Water Data
Reliability Analysis and Action Plan (2003): For State Reported Public Water System Data in
the EPA Safe Drinking Water Information System/Federal Version (SDWIS/FED), EPA 816-R-
03-021.
U.S. Environmental Protection Agency, October 2000, Office of Water, Data Reliability
Analysis of the EPA Safe Drinking Water Information System/Federal Version (SDWIS/FED),
EPA 816-R-00-020.
Page 56
-------
APPTADTX A: TCR VTOT.ATTOXS: AVERAGES FOR 1997-2003. BY SYSTEM SIZE
MCL Violations
Monitoring & Reporting Violations
Total
Acute
Monthly
Routine
Repeat
Major
Minor
Major
Minor
AVERAGE OF ANNUAL NUMBERS OF SYSTEMS WITH VIOLATIONS
<=100
4,071
655
3,721
12,767
1,044
1,076
477
101-500
1,975
369
1,803
4,818
650
443
273
501-1,000
386
68
359
752
152
59
60
1,001-3,300
419
47
399
447
395
50
56
3,301-10,000
239
20
230
92
188
24
28
10,001-50,000
166
14
161
32
104
17
20
50,001-100,000
11
3
9
7
11
2
4
>100,000
7
3
5
4
4
4
5
All Sizes
7,274
1,179
6,688
18,917
2,547
1,676
925
AVERAGE OF ANNUAL NUMBERS OF VIOLATIONS
<=100
5,335
792
4,543
21,111
1,240
1,226
530
101-500
2,854
557
2,298
8,014
799
510
307
501-1,000
577
110
467
1,165
186
64
67
1,001-3,300
574
65
508
646
534
53
68
3,301-10,000
298
23
275
120
246
26
32
10,001-50,000
216
14
202
42
127
18
25
50,001-100,000
14
3
10
8
13
3
6
>100,000
10
3
6
5
5
4
10
All Sizes
9,878
1,568
8,310
31,112
3,151
1,904
1,045
AVERAGE OF ANNUAL NUMBERS OF VIOLATIONS PER SYSTEM
<=100
0.056
0.008
0.048
0.185
0.018
0.012
0.006
101-500
0.066
0.013
0.053
0.116
0.019
0.006
0.007
501-1,000
0.058
0.011
0.047
0.067
0.055
0.006
0.007
1,001-3,300
0.059
0.007
0.053
0.026
0.053
0.005
0.007
3,301-10,000
0.064
0.005
0.059
0.014
0.043
0.006
0.007
10,001-50,000
0.072
0.005
0.068
0.017
0.029
0.006
0.008
50,001-100,000
0.031
0.007
0.023
0.015
0.014
0.012
0.014
>100,000
0.027
0.010
0.017
0.187
0.019
0.011
0.028
All Sizes
0.059
0.009
0.050
0.187
0.019
0.011
0.006
AVERAGE OF ANNUAL PERCENTAGE OF SYSTEMS WITH VIOLATIONS
<=100
4.3%
0.7%
3.9%
13.5%
1.1%
1.1%
0.5%
101-500
4.5%
0.8%
4.2%
11.1%
1.5%
1.0%
0.6%
501-1,000
3.9%
0.7%
3.6%
7.5%
1.5%
0.6%
0.6%
1,001-3,300
4.3%
0.5%
4.1%
4.6%
4.1%
0.5%
0.6%
3,301-10,000
5.1%
0.4%
4.9%
2.0%
4.0%
0.5%
0.6%
10,001-50,000
5.6%
0.5%
5.4%
1.1%
3.5%
0.6%
0.7%
50,001-100,000
2.4%
0.7%
2.0%
1.5%
2.3%
0.5%
1.0%
>100,000
1.9%
0.8%
1.4%
1.0%
1.1%
1.0%
1.5%
All Sizes
4.4%
0.7%
4.0%
11.4%
1.5%
1.0%
0.6%
Page 57
-------
APPENDIX B: TCR VIOLATIONS: AVERAGES FOR 1997-2003, BY SYSTEM TYPE
MCL Violations
Monitoring & Reporting Violations
Total
Acute
Monthly
Routine
Repeat
Major
Minor
Major
Minor
AVERAGE OF ANNUAL NUMBERS OF SYSTEMS WITH VIOLATIONS
cws
2,787
393
2,606
4,292
1,504
592
413
NTNCWS
876
147
806
2,110
207
137
93
TNCWS
3,611
639
3,276
12,515
837
947
418
All Types
4,243
1,179
6,688
18,917
2,547
1,676
925
AVERAGE
OF ANNUAL NUMBERS OF VIOLATIONS
CWS
4,109
651
3,458
8,460
1,918
700
477
NTNCWS
1,172
168
1,004
2,934
253
148
106
TNCWS
4,596
749
3,848
19,718
980
1,056
461
All Types
9,878
1,568
8,310
31,112
3,151
1,904
1,045
AVERAGE
OF ANNUAL NUMBER OF VIOLATIONS PER SYSTEM
CWS
0.076
0.012
0.064
0.157
0.036
0.013
0.009
NTNCWS
0.059
0.008
0.050
0.147
0.013
0.007
0.005
TNCWS
0.050
0.008
0.042
0.214
0.011
0.011
0.005
All Types
0.059
0.009
0.050
0.187
0.019
0.011
0.006
AVERAGE
OF ANNUAL PERCENTAGE OF SYSTEMS WITH VIOLATIONS
CWS
5.2%
0.7%
4.8%
7.9%
2.8%
1.1%
0.8%
NTNCWS
4.4%
0.7%
4.0%
10.6%
1.0%
0.7%
0.5%
TNCWS
3.9%
0.7%
3.5%
13.6%
0.9%
1.0%
0.5%
All Types
4.4%
0.7%
4.0%
11.4%
1.5%
1.0%
0.6%
Page 58
-------
APPENDIX C: TCR VIOLATIONS: AVERAGES FOR 1997-2003, BY SOURCE WATER
MCL Violations
Monitoring & Reporting Violations
Total
Acute
Monthly
Routine
Repeat
Major
Minor
Major
Minor
AVERAGE OF ANNUAL NUMBERS OF SYSTEMS WITH VIOLATIONS
GU 65
28
50
176
46
29
30
GW 6,739
976
6,276
17,792
2,066
1,558
814
SW 469
174
361
949
434
89
80
All Source Types 7,274
1,179
6,688
18,917
2,547
1,676
925
AVERAGE OF ANNUAL NUMBERS OF VIOLATIONS
GU 101
37
64
370
63
36
40
GW 8,902
1,166
7,736
28,555
2,500
1,751
908
SW 873
365
509
2,187
588
117
97
All Source Types 9,878
1,568
8,310
31,112
3,151
1,904
1,045
AVERAGE OF ANNUAL NUMBER OF VIOLATIONS PER SYSTEM
GU 0.167
0.025
0.100
0.566
0.095
0.058
0.069
GW 0.058
0.027
0.051
0.188
0.016
0.011
0.006
SW 0.066
0.009
0.038
0.163
0.044
0.009
0.007
All Source Types 0.059
0.009
0.050
0.187
0.019
0.011
0.006
AVERAGE OF ANNUAL PERCENTAGE OF SYSTEMS WITH VIOLATIONS
GU 10.6%
4.9%
8.0%
27.6%
7.2%
4.6%
5.2%
GW 4.4%
0.6%
4.1%
11.7%
1.4%
1.0%
0.5%
SW 3.5%
1.3%
2.7%
7.1%
3.3%
0.7%
0.6%
All Source Types 4.4%
0.7%
4.0%
11.4%
1.5%
1.0%
0.6%
Page 59
-------
APPENDIX D
TCR MCL VIOLATIONS OVER TIME, BY PARAMETER
Page 60
-------
Exhibit D-l: TCR MCL Violations by System Size: 1997 - 2003
Number of Systems With TCR MCL Violations
Size Category
1997
1998 ;
1999 ,
2000
2001 , 2002 ,
2003 TOTALS
<=100
4,278
4,215
4,144
3,923
3,914
3,952
4,072
28,498
101-500
2,061
2,165
2,049
1,893
1,896
1,890
1,869
13,823
501-1,000
413
389
410
363
403
388
338
2,704
1,001-3,300
477
456
386
397
421
409
386
2,932
3,301-10,000
274
242
214
233
235
221
252
1,671
10,001-50,000
196
178
153
145
155
173
165
1,165
50,001-100,000
19
14
10
9
6
5
14
77
>100,000
10
5
10
9
5
2
6
47
TOTALS
7,728
7,664
7,376
6,972
7,035
7,040
7,102
50,917
Number of TCR MCL Violations
Size Category
1997
2000 |
2001
2002
2003
TOTALS
<=100
5,721
5,858
5,433
4,900
5,150
5,106
5,177
37,345
101-500
3,075
3,549
3,145
2,544
2,782
2,453
2,433
19,981
501-1,000
626
668
671
503
630
510
434
4,042
1,001-3,300
650
675
558
549
569
536
479
4,016
3,301-10,000
345
299
292
283
296
280
289
2,084
10,001-50,000
268
242
203
187
201
207
204
1,512
50,001-100,000
22
18
16
9
9
7
15
96
>100,000
12
8
17
11
7
2
10
67
TOTALS
10,719
11,317
10,335
8,986
9,644
9,101
9,041
69,143
Average
Number of
TCR MCL
Violations Per System
Size Category
1997
1998
1999
2000
2001
2002
2003
Avg
<=100
0.058
0.059
0.056
0.051
0.055
0.057
0.058
0.056
101-500
0.071
0.081
0.072
0.058
0.064
0.057
0.057
0.066
501-1,000
0.063
0.067
0.067
0.050
0.063
0.051
0.043
0.058
1,001-3,300
0.067
0.070
0.058
0.057
0.059
0.055
0.049
0.059
3,301-10,000
0.075
0.065
0.063
0.060
0.063
0.058
0.059
0.064
10,001-50,000
0.092
0.083
0.069
0.062
0.066
0.069
0.066
0.072
50,001-100,000
0.052
0.040
0.036
0.019
0.019
0.016
0.032
0.031
>100,000
0.035
0.023
0.047
0.031
0.020
0.005
0.027
0.027
TOTALS
0.063
0.066
0.062
0.054
0.058
0.056
0.056
0.059
Percent of Systems With TCR MCL Violations
Size Category
1997
1998
1999
2000
2001
2002
2003
Avg
<=100
4.3%
4.3%
4.3%
4.1%
4.2%
4.4%
4.5%
4.3%
101-500
4.7%
4.9%
4.7%
4.3%
4.4%
4.4%
4.4%
4.5%
501-1,000
4.2%
3.9%
4.1%
3.6%
4.0%
3.9%
3.4%
3.9%
1,001-3,300
4.9%
4.8%
4.0%
4.1%
4.3%
4.2%
4.0%
4.3%
3,301-10,000
6.0%
5.3%
4.6%
5.0% :
5.0%
4.6%
5.2%
5.1%
10,001-50,000
6.7%
6.1%
5.2%
4.8%
5.1%
5.7%
5.4%
5.6%
50,001-100,000
4.5%
3.1%
2.3%
1.9%
1.3%
1.1%
2.9%
2.4%
>100,000
2.9%
1.4%
2.8%
2.5%
1.4%
0.5%
1.6%
1.9%
TOTALS
4.5%
4.5%
4.4%
4.2%
4.3%
4.4%
4.4%
4.4%
Page 61
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Exhibit D-2: Number and Frequency of TCR MCL Violations by System Type:
1997 - 2003
Number of Systems With TCR MCL
. Violations
System Type
1997
1998
1999
2000
2001
2002
2003
TOTALS
cws
3,142
3,217
2,850
2,714
2,696
2,515
2,378
19,512
NTNCWS
888
857
911
854
836
866
917
6,129
TNCWS
3,698
3,590
3,615
3,404
3,503
3,659
3,807
25,276
TOTALS
7,728
7,664
7,376
6,972
7,035
7,040
7,102
50,917
Number
of TCR MCL Violations
System Type
1997
1998
1999
2000
2001
2002
2003
TOTALS
CWS
4,611
5,185
4,500
3,783
4,157
3,402
3,127
28,765
NTNCWS
1,202
1,183
1,237
1,121
1,121
1,138
1,202
8,204
TNCWS
4,906
4,949
4,598
4,082
4,366
4,561
4,712
32,174
TOTALS
10,719
11,317
10,335
8,986
9,644
9,101
9,041
69,143
Average
Number of TCR MCL Violations Per
System
System Type
1997
1998
1999
2000
2001
: 2002
2003
Avg
CWS
0.084
0.095
0.083
0.070
0.077
0.064
0.059
0.076
NTNCWS
0.060
0.058
0.062
0.055
0.056
0.061
0.061
0.059
TNCWS
0.051
0.052
0.049
0.044
0.048
0.051
0.053
0.050
TOTALS
0.063
0.066
0.062
0.054
0.058
0.056
0.056
0.059
Percent of Systems With TCR MCL Violations
System Type
1997
1998
1999
2000
2001
2002
2003
Avg
CWS
5.7%
5.9%
5.3%
5.0%
5.0%
4.7%
4.5%
5.2%
NTNCWS
4.4%
4.2%
4.5%
4.2%
4.2%
4.6%
4.7% i
4.4%
TNCWS
3.9%
3.7%
3.9%
3.7%
3.8%
4.1%
4.3%
3.9%
TOTALS
4.5%
4.5%
4.4%
4.2%
4.3%
4.4%
4.4%
4.4%
Page 62
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Exhibit D-3: Number and Frequency of TCR MCL Violations by Source: 1997 - 2003
Source
GU
GW
SW
TOTALS
Source
GU
GW
SW
TOTALS
Source
GU
GW
SW
TOTALS
Source
GU
GW
SW
TOTALS
Number of Systems With TCR MCL Violations
1997 1998 1999 2000 2001 2002 2003 TOTALS
77
85
61
42
57
69
62
453
7,097
7,016
6,773
6,462
6,578
6,576
6,669
47,171
549
561
541
468
400
395
371 i
3,285
7,728
7,664
7,376
6,972
7,035
7,040
7,102
50,917
Number of TCR MCL Violations
1997
1998
1999
2000
2001
2002
2003
TOTALS
119
147
101
58 i
93 i
94
95 I
707
9,600
9,920
9,117
8,164
8,653
8,395
8,462
62,311
992
1,248
1,116
764
898
612
484
6,114
10,719
11,317
10,335
8,986
9,644
9,101
9,041
69,143
Average Number of TCR MCL Violations Per System
1997
1998
1999
2000
2001
2002
2003
Avg
0.295
0.306
0.198
0.097
0.097
0.089
0.088
0.167
0.061
0.063
0.059
0.053
0.057
0.057
0.058
0.058
0.075
0.095
0.087
0.056
0.065
0.045
0.035
0.066
0.063
0.066
0.062
0.054
0.058
0.056
0.056
0.059
Percent of Systems With TCR MCL Violations
1997
1998
1999
2000
2001
2002
2003
Avg
19.1%
: 17.7% :
12.0%
7.0%
5.9%
6.5%
5.7%
10.6%
4.5%
4.5%
4.4%
4.2%
4.4%
4.5%
4.6%
4.4%
4.1%
4.3%
4.2%
3.5%
2.9%
2.9%
2.7%
3.5%
4.5%
4.5%
4.4%
4.2%
4.3%
4.4%
4.4%
4.4%
Page 63
-------
APPENDIX E
TCR ACUTE MCL VIOLATIONS OVER TIME, BY PARAMETER
Page 64
-------
Exhibit E-l: TCR Acute MCL Violations by System Size: 1997 - 2003
Number of Systems With TCR Acute MCL Violations
Size Category
1997
1998
1999
2000
2001
2002
2003
TOTALS
<=100
1,106
987
725
433
427
471
434
4,583
101-500
545
581
441
284
305
212
215
2,583
501-1,000
107
93
90
53
54
47
34
478
1,001-3,300
59
67
57
42
41
37
27
330
3,301-10,000
23
18
32
19
13
17
16
138
10,001-50,000
20
21
12
6
12
9
16
96
50,001-100,000
10
2
2
2
3
1
2
22
>100,000
4
3
3
5
2
0
4
21
TOTALS
1,874
1,772
1,362
844
857
794
748
8,251
_ Number of TCR Acute MCL Violations
Size Category
1997
1998 ,
1999 ,
2000 |
2001 ,
2002
2003
TOTALS
<=100
1,319
1,283
904
494
542
537
462
5,541
101-500
810
989
696
377
520
269
236
3,897
501-1,000
163
174
154
78
102
64
38
773
1,001-3,300
88
99
83
60
53
45
29
457
3,301-10,000
26
20
39
24
18
17
16
160
10,001-50,000
20
23
12
6
13
9
17
100
50,001-100,000
11
2
2
2
3
1
2
23
>100,000
4
3
5
5
3
0
4
24
TOTALS
2,441
2,593
1,895
1,046
1,254
942
804
10,975
Average Number of TCR Acute MCL Violations Per System
Size Category
1997
2000 !
2001 |
2003
Avg
<=100
0.013
0.013
0.009
0.005
0.006
0.006
0.005
0.008
101-500
0.019
0.022
0.016
0.009
0.012
0.006
0.005
0.013
501-1,000
0.016
0.017
0.015
0.008
0.010
0.006
0.004
0.011
1,001-3,300
0.009
0.010
0.009
0.006
0.005
0.005
0.003
0.007
3,301-10,000
0.006
0.004
0.008
0.005
0.004
0.004
0.003
0.005
10,001-50,000
0.007
0.008
0.004
0.002
0.004
0.003
0.006
0.005
50,001-100,000
0.026
0.004
0.005
0.004
0.006
0.002
0.004
0.007
>100,000
0.012
0.009
0.014
0.014
0.008
0.000
0.011
0.010
TOTALS
0.014
0.015
0.011
0.006
0.008
0.006
0.005
0.009
Percent of Systems With TCR Acute
MCL Violations
Size Category
1997
1998
1999
2000
2001
2002
2003
Avg
<=100
1.1%
1.0% 5
0.8%
0.5%
0.5%
0.5%
0.5%
0.7%
101-500
1.3%
1.3%
1.0%
0.6%
0.7%
0.5%
0.5%
0.8%
501-1,000
1.1%
0.9%
0.9%
0.5%
0.5%
0.5%
0.3%
0.7%
1,001-3,300
0.6%
0.7%
0.6%
0.4%
0.4%
0.4%
0.3%
0.5%
3,301-10,000
0.5%
0.4%
0.7%
0.4%
0.3%
0.4%
0.3%
0.4%
10,001-50,000
0.7%
0.7%
0.4%
0.2%
0.4%
0.3%
0.5%
0.5%
50,001-100,000
2.4%
0.4%
0.5%
0.4%
0.6%
0.2%
0.4%
0.7%
>100,000
1.2%
0.9%
0.8%
1.4%
0.6%
0.0%
1.1%
0.8%
TOTALS
1.1%
1.0%
0.8%
0.5%
0.5%
0.5%
0.5%
0.7%
Page 65
-------
Exhibit E-2: Number and Frequency of TCR Acute MCL Violations by System Type:
1997 - 2003
Number of Systems With TCR Acute MCL Violations
System Type
1997
; 1998
1999
2000
2001
2002
2003
TOTALS
cws
547
580
466
384
357
224
191
2,749
NTNCWS
203
208
199
115
96
105
104
1,030
TNCWS
1,124
984
697
345
404
465
453
4,472
TOTALS
1,874
1,772
1,362
844
857
794
748
8,251
Number of TCR Acute MCL Violations
System Type
1997
; 1998
1999
2000
2001
2002
2003
TOTALS
CWS
874
1,096
850
530
698
310
202
4,560
NTNCWS
225
241
225
148
103
118
114
1,174
TNCWS
1,342
1,256
820
368
453
514
488
5,241
TOTALS
2,441
2,593
1,895
1,046
1,254
942
804
10,975
Average Number of TCR Acute MCL Violations Per System
System Type
1997 ;
1998
1999
2000
2001
2002
2003
Avg
CWS
0.016
0.020
0.016
0.010
0.013
0.006
0.004
0.012
NTNCWS
0.011
0.012
0.011
0.007
0.005
0.006
0.006
0.008
TNCWS
0.014
0.013
0.009
0.004
0.005
0.006
0.006
0.008
TOTALS
0.014
0.015
0.011
0.006
0.008
0.006
0.005
0.009
Percent of Systems With TCR Acute MCL Violations
System Type
1997
1998
1999
2000
2001
2002
2003
Avg
CWS
1.0%
1.1%
0.9%
0.7%
0.7%
0.4%
0.4%
0.7%
NTNCWS
1.0%
1.0%
1.0%
0.6%
0.5%
0.6%
0.5%
0.7%
TNCWS
1.2%
1.0%
0.7%
0.4%
0.4%
0.5%
0.5%
0.7%
TOTALS
1.1%
1.0%
0.8%
0.5%
0.5%
0.5%
0.5%
0.7%
Page 66
-------
Exhibit E-3: Number and Frequency of TCR Acute MCL Violations by Source: 1997 - 2003
Number of Systems With TCR Acute MCL Violations
Source
1997
1998
1999
2000
2001
2002
2003
TOTALS
GU
41
45
34
15
23
19
18
195
GW
1,615
1,480
1,072
632
686
685
664
6,834
SW
217
247
256
197
148
90
66
1,221
TOTALS
1,874
1,772
1,362
844
857
794
748
8,251
Number of TCR Acute MCL Violations
Source
1997
1998
1999
2000
2001
2002
2003
TOTALS
GU
54
70
49
17
24
24
22
260
GW
1,941
1,920
1,315
704
837
742
703
8,162
SW
445
603
531
325
393
176
79
2,552
TOTALS
2,441
2,593
1,895
1,046
1,254
942
804
10,975
Average Number of TCR Acute MCL Violations Per System
Source
1997
1998
1999
2000
2001
2002
2003
Avg
GU
0.134
0.012
0.009
0.005
0.006
0.005
0.005
0.025
GW
0.034
0.046
0.041
0.024
0.029
0.013
0.006
0.027
SW
0.014
0.015
0.011
0.006
0.008
0.006
0.005
0.009
TOTALS
0.014
0.015
0.011
0.006
0.008
0.006
0.005
0.009
Percent of Systems With TCR Acute MCL Violations
Source
1997
1998
1999
2000
2001
2002
2003
Avg
GU
10.1%
9.4%
6.7%
j 2.5%
2.4%
1.8%
1.7%
4.9%
GW
1.0%
0.9%
0.7%
0.4%
0.5%
: 0.5%
0.45%
0.6%
SW
1.6%
1.9%
2.0%
1.5%
1.1%
0.7%
0.48%
1.3%
TOTALS
1.1%
1.0%
0.8%
0.5%
0.5%
0.5%
0.46%
0.7%
Page 67
-------
APPENDIX F
TCR MONTHLY MCL VIOLATIONS OVER TIME, BY PARAMETER
Page 68
-------
Exhibit F-l: TCR Monthly MCL Violations by System Size: 1997 - 2003
Number of Systems With TCR Monthly MCL Violations
Size Category
1997
1998
1999
2000
2001
2002
2003
TOTALS
<=100
3,674
3,772
3,736
3,650
3,692
3,673
3,853
26,050
101-500
1,812
1,954
1,838
1,735
1,756
1,772
1,755
12,622
501-1,000
365
365
376
338
389
360
323
2,516
1,001-3,300
452
432
365
378
404
391
371
2,793
3,301-10,000
267
236
202
222
230
211
241
1,609
10,001-50,000
192
172
147
143
151
170
155
1,130
50,001-100,000
11
13
9
7
5
5
12
62
>100,000
7
3
10
6
3
2
3
34
TOTALS
6,780
6,947
6,683
6,479
6,630
6,584
6,713
46,816
Number of TCR Monthly MCL Violations
Size Category
1997
1998
—
2000
2002
2003
TOTALS
<=100
4,402
4,575
4,529
4,406
4,608
4,569
4,715
31,804
101-500
2,265
2,560
2,449
2,167
2,262
2,184
2,197
16,084
501-1,000
463
494
517
425
528
446
396
3,269
1,001-3,300
562
576
475
489
516
491
450
3,559
3,301-10,000
319
279
253
259
278
263
273
1,924
10,001-50,000
248
219
191
181
188
198
187
1,412
50,001-100,000
11
16
14
7
6
6
13
73
>100,000
8
5
12
6
4
2
6
43
TOTALS
8,278
8,724
8,440
7,940
8,390
8,159
8,237
58,168
Average Number of TCR Monthly MCL Violations
Per System
Size Category
1997
1998
1999
2000
2001
2002
2003
Avg
<=100
0.044
0.046
0.047
0.046
0.049
0.051
0.053
0.048
101-500
0.052
0.058
0.056
0.050
0.052
0.051
0.051
0.053
501-1,000
0.047
0.049
0.052
0.042
0.053
0.045
0.039
0.047
1,001-3,300
0.058
0.060
0.050
0.051
0.053
0.051
0.046
0.053
3,301-10,000
0.070
0.061
0.055
0.055
0.059
0.055
0.056
0.059
10,001-50,000
0.085
0.075
0.065
0.060
0.062
0.066
0.061
0.068
50,001-100,000
0.026
0.036
0.032
0.015
0.013
0.013
0.027
0.023
>100,000
0.023
0.014
0.033
0.017
0.011
0.005
0.016
0.017
TOTALS
0.049
0.051
0.050
0.047
0.051
0.051
0.051
0.050
Percent of Systems With TCR Monthly MCL Violations
Size Category
1997
1998
1999
2000
2001
2002
2003
Avg
<=100
3.7%
3.8%
3.9% =
3.8%
3.9%
4.1%
4.3%
3.9%
101-500
4.2%
4.4%
4.2%
4.0%
4.0%
4.2%
4.1%
4.2%
501-1,000
3.7%
3.6%
3.8%
3.4%
3.9%
3.6%
3.2%
3.6%
1,001-3,300
4.7%
4.5%
3.8%
3.9%
4.2%
4.0%
3.8%
4.1%
3,301-10,000
5.8%
5.2%
4.4%
4.7%
4.9%
4.4%
4.9%
4.9%
10,001-50,000
6.6%
5.9%
5.0%
4.7%
5.0%
5.6%
5.0%
5.4%
50,001-100,000
2.6%
2.9%
2.0%
1.5%
1.1%
1.1%
2.5%
2.0%
>100,000
2.0%
0.9%
2.8%
1.7%
0.8%
0.5%
0.8%
1.4%
TOTALS
4.0%
4.1%
4.0%
3.9%
4.0%
4.1%
4.2%
4.0%
Page 69
-------
Exhibit F-2: Number and Frequency of TCR Monthly MCL Violations by System Type:
1997 - 2003
Number of Systems With TCR Monthly MCL Violations
System Type 1997 : 1998 1999 2000 2001 2002 2003 TOTALS
cws
2,878
2,991
2,648
2,503
2,548
2,398
2,277
18,243
NTNCWS
809
784
799
774
803
805
867
5,641
TNCWS
3,093
3,172
3,236
3,202
3,279
3,381
3,569
22,932
TOTALS
6,780
6,947
6,683
6,479
6,630
6,584
6,713
46,816
Number of
TCR Monthly MCL
Violations
System Type
1997
1998
1999
2000
2001
2002
2003
TOTALS
CWS
3,737
4,089
3,650
3,253
3,459
3,092
2,925
24,205
NTNCWS
977
942
1,012
973
1,018
1,020
1,088
7,030
TNCWS
3,564
3,693
3,778
3,714
3,913
4,047
4,224
26,933
TOTALS
8,278
8,724
8,440
7,940
8,390
8,159
8,237
58,168
Average Number of TCR Monthly MCL Violations Per System
System Type
1997
; 1998
1999
2000
2001
2002
2003
Avg
CWS
0.068
0.075
0.068
0.060
0.064
0.058
0.055
0.064
NTNCWS
0.049
0.047
0.050
0.047
0.051
0.055
0.055
0.050
TNCWS
0.037
0.039
0.040
0.040
0.043
0.045
0.048
0.042
TOTALS
0.049
0.051
0.050
0.047
0.051
0.051
0.051
0.050
Percent of Systems With TCR Monthly MCL
Violations
System Type
1997
; 1998
1999
2000
2001
2002
2003
Avg
CWS
5.3%
t 5.5% ;
4.9%
4.6%
4.7%
4.5%
4.3%
4.8%
NTNCWS
4.0%
3.9%
4.0%
3.8%
4.0%
4.3%
4.4%
4.0%
TNCWS
3.2%
3.3%
3.5%
3.4%
3.6%
3.8%
4.0%
3.5%
TOTALS
4.0%
4.1%
4.0%
3.9%
4.0%
4.1%
4.2%
4.0%
Page 70
-------
Exhibit F-3: Number and Frequency of TCR Monthly MCL Violations by Source: 1997 -
2003
Number of Systems With TCR Monthly MCL Violations
Source
1997
1998
1999
2000
2001
2002
2003
TOTALS
GU
57
64
42
30
46
56
53
348
GW
6,295
6,453
6,259
6,131
6,256
6,198
6,339
43,931
SW
424
428
381
318
328
330
321
2,530
TOTALS
6,780
6,947
6,683
6,479
6,630
6,584
6,713
46,816
Number
of TCR
Monthly MCL Violations
Source
1997
1998
1999
2000
2001
2002
2003
TOTALS
GU
65
77
52
41
69
70 :
73
447
GW
7,659
8,000
7,802
7,460
7,816
7,653
7,759
54,149
SW
547
645
585
439
505
436
405
3,562
TOTALS
8,278
8,724
8,440
7,940
8,390
8,159
8,237
58,168
Average Number of TCR Monthly MCL Violations Per System
Source
1997
1998
1999
2000
2001
2002
2003
Avg
GU
0.161
0.160
0.102
0.068
0.072
0.066
0.067
0.100
GW
0.049
0.051
0.051
0.049
0.052
0.052
0.053
0.051
SW
0.041
0.049
0.045
0.032
0.037
0.032
0.030
0.038
TOTALS
0.049
0.051
0.050
0.047
0.051
0.051
0.051
0.050
Percent of Systems With TCR Monthly MCL Violations
-jj | f i | |" 1
Source
1997
1998
1999
2000
2001
2002
2003
Avg
GU
14.1%
13.3%
8.2%
5.0%
4.8%
5.3%
4.9%
8.0%
GW
4.0%
4.1%
4.1%
4.0%
4.2%
4.2%
4.3%
4.1%
SW
3.2%
3.3%
3.0%
2.3%
2.4%
2.4%
2.4%
2.7%
TOTALS
4.0%
4.1%
4.0%
3.9%
4.0%
4.1%
4.2%
4.0%
Page 71
-------
APPENDIX G
TCR ROUTINE: MAJOR MONITORING & REPORTING VIOLATIONS OVER TIME,
BY PARAMETER
Page 72
-------
Exhibit G-l: TCR Routine: Major Monitoring & Reporting Violations by System Size:
1997 - 2003
Number of Systems With TCR Routine: Major Monitoring & Reporting & Reporting & Reporting
Violations
Size Category
1997
1998
1999
2000
2001
2002
2003
TOTALS
<=100
13,343
10,970
14,363
12,777
12,673
12,722
12,521
89,369
101-500
5,328
4,655
5,119
4,801
4,783
4,407
4,633
33,726
501-1,000
868
725
721
733
741
713
760
5,261
1,001-3,300
511
428
366
402
564
405
450
3,126
3,301-10,000
96
87
65
91
132
75
96
642
10,001-50,000
41
30
21
26
34
31
38
221
50,001-100,000
8
12
3
7
8
2
7
47
>100,000
6
5
3
2
7
1
1
25
TOTALS
20,201
16,912
20,661
18,839
18,942
18,356
18,506
132,417
Number of TCR Routine: Major Monitoring & Reporting Violations
Size Category
1997
1998
1999
2000
2001
2002
2003
TOTALS
<=100
22,044
17,826
23,224 !
21,578
20,603
21,669
20,834
147,778
101-500
9,399
7,872
7,956
7,637
7,759
7,489
7,986
56,098
501-1,000
1,421
1,086
997
1,082
1,105
1,176
1,289
8,156
1,001-3,300
753
608
469
598
798
607
688
4,521
3,301-10,000
128
118
76
128
165
102
126
843
10,001-50,000
48
43
29
36
55
42
44
297
50,001-100,000
8
13
3
7
12
2
9
54
>100,000
12
8
3
2
9
3
1
38
TOTALS
33,813
27,574
32,757
31,068
30,506
31,090
30,977
217,785
Average Number of TCR Routine: Major Monitoring & Reporting Violations Per System
Size Category
1997
1998
1999
2000
2001
2002
2003
Avg
<=100
0.222
0.181
0.241
0.225
0.220
0.240
0.232
0.223
101-500
0.216
0.179
0.183
0.175
0.179
0.176
0.186
0.185
501-1,000
0.143
0.109
0.100
0.108
0.110
0.118
0.128
0.116
1,001-3,300
0.078
0.063
0.049
0.062
0.082
0.062
0.071
0.067
3,301-10,000
0.028
0.026
0.016
0.027
0.035
0.021
0.026
0.026
10,001-50,000
0.016
0.015
0.010
0.012
0.018
0.014
0.014
0.014
50,001-100,000
0.019
0.029
0.007
0.015
0.026
0.004
0.019
0.017
>100,000
0.035
0.023
0.008
0.006
0.025
0.008
0.003
0.015
TOTALS
0.198
0.162
0.195
0.185
0.184
0.193
0.192
0.187
Percent of Systems With TCR Routine: Major Monitoring & Reportinc
Violations
Size Category
1997
1998
1999
2000
2001
2003
Avg
<=100
13.4%
11.1%
14.9%
13.3%
13.5%
14.1%
14.0%
13.5%
101-500
12.3%
10.6%
11.7%
11.0%
11.0%
10.3%
10.8%
11.1%
501-1,000
8.7%
7.2%
7.2%
7.3%
7.4%
7.1%
7.5%
7.5%
1,001-3,300
5.3%
4.5%
3.8%
4.2%
5.8%
4.2%
4.6%
4.6%
3,301-10,000
2.1%
1.9%
1.4%
1.9%
2.8%
1.6%
2.0%
2.0%
10,001-50,000
1.4%
1.0%
0.7%
0.9%
1.1%
1.0%
1.2%
1.1%
50,001-100,000
1.9%
2.7%
0.7%
1.5%
1.7%
0.4%
1.5%
1.5%
>100,000
1.7%
1.4%
0.8%
0.6%
2.0%
0.3%
0.3%
1.0%
TOTALS
11.8%
9.9%
12.3%
11.2%
11.4%
11.4%
11.5%
11.4%
Page 73
-------
Exhibit G-2: Number and Frequency of TCR Routine: Major Monitoring & Reporting
Violations by System Type: 1997 - 2003
Number of Systems With TCR Routine: Major Monitoring & Reporting Violations
System Type 1997 1998 1999 2000 2001 2002 2003 TOTALS
cws
5,251
4,776
4,124
4,224
4,107
3,669
3,893
30,044
NTNCWS
2,783
2,144
2,042
2,086
2,002
1,890
1,822
14,769
TNCWS
12,167
9,992
14,495
12,529
12,833
12,797
12,791
87,604
TOTALS
20,201
16,912
20,661
18,839
18,942
18,356
18,506
132,417
Number of
TCR Routine: Major
Monitoring
& Reporting Violations
System Type
1997
1998
1999
2000
2001
2002
2003
TOTALS
CWS
10,851
9,291
7,228
7,758
7,822
7,810
8,461
59,221
NTNCWS
3,988
3,067
2,769
2,944
2,739
2,563
2,471
20,541
TNCWS
18,974
15,216
22,760
20,366
19,945
20,717
20,045
138,023
TOTALS
33,813
27,574
32,757
31,068
30,506
31,090
30,977
217,785
Average Number of TCR Routine: Major Monitoring & Reporting Violations Per System
System Type
1997
1998
1999
2000
2001
2002 :
2003
Avg
CWS
0.198
0.171
0.134
0.143
0.145
0.146
0.159
0.157
NTNCWS
0.198
0.151
0.138
0.143
0.136
0.137
0.126
0.147
TNCWS
0.198
0.159
0.243
0.218
0.218
0.232
0.227
0.214
TOTALS
0.198
0.162
0.195
0.185
0.184
0.193
0.192
0.187
Percent of Systems With TCR Routine: Major Monitoring & Reporting Violations
System Type
1997
1998
1999
2000
2001
2002
2003
Avg
CWS
9.6%
8.8%
7.6%
7.8%
7.6%
6.9%
7.3%
7.9%
NTNCWS
13.8%
10.6%
10.2%
10.1%
10.0%
10.1%
9.3% !
10.6%
TNCWS
12.7%
10.4%
15.5%
13.4%
14.0%
14.3%
14.5%
13.6%
TOTALS
11.8%
9.9%
12.3%
11.2%
11.4%
11.4%
11.5%
11.4%
Page 74
-------
Exhibit G-3: Number and Frequency of TCR Routine: Major Monitoring & Reporting
Violations by Source: 1997 - 2003
Number of Systems With TCR Routine: Major Monitoring & Reporting Violations
Source 1997 1998 1999 2000 2001 ; 2002 2003 TOTALS
GU 189 190 141 155 175 209 170 1,229
GW 18.936 15,726 19,522 17,767 17,832 17,352 17,411 124,546
SW 1,075 995 998 917 935 795 925 6,640
TOTALS 20,201 16,912 20,661 18,839 18,942 18,356 18,506 132,417
Number of TCR Routine: Major Monitoring & Reporting Violations
Source ; 1997 1998 : 1999 2000 2001 : 2002 2003 TOTALS
GU 366 : 386 ; 273 » 297 : 386 s 461 : 419 2,588
GW 30,847 24,971 30,546 29,037 28,018 28,437 28,030 199,886
SW 2,598 2,215 1,938 1,734 2,102 2,192 2,528 15,307
TOTALS 33,813 27,574 32,757 31,068 30,506 31,090 30,977 217,785
Average Number of TCR Routine: Major Monitoring & Reporting Violations Per System
Source
1997
1998
1999
2000
2001
2002
2003
Avg
GU
0.906
0.804
0.535
0.495
0.403
0.436
0.386
0.566
GW
0.196
0.159
0.198
0.189
0.186
0.194
0.191
0.188
SW
0.196
0.169
0.150
0.128
0.153
0.162
0.185
0.163
TOTALS
0.198
0.162
0.195
0.185
0.184
0.193
0.192
0.187
Percent of Systems With TCR Routine: Major Monitoring & Reporting Violations
Source
1997
1998
1999
2000
2001
2002
2003
Avg
GU
46.8%
39.6%
27.6%
: 25.8% :
18.2%
19.8%
15.7%
27.6%
GW
12.1%
10.0%
: 12.6%
11.6%
11.8%
11.8%
11.9%
11.7%
SW
8.1%
7.6%
7.7%
6.8%
6.8%
5.9%
6.8%
7.1%
TOTALS
11.8%
9.9%
12.3%
11.2%
11.4%
11.4%
11.5%
11.4%
Page 75
-------
APPENDIX H
TCR ROUTINE: MINOR MONITORING & REPORTING VIOLATIONS OVER TIME,
BY PARAMETER
Page 76
-------
Exhibit H-l: TCR Routine: Minor Monitoring & Reporting Violations by System Size:
1997 - 2003
Number of Systems With TCR Routine: Minor Monitoring & Reporting Violations
Size Category
1997
1998
1999
2000
2001
2002
2003
TOTALS
<=100
i 1,289 i
1,273
1,108
988
875
905
868
7,306
101-500
809
774
759
651
497
517
544
4,551
501-1,000
181
192
167
143
117
133
129
1,062
1,001-3,300
449
434
358
381
386
347
409
2,764
3,301-10,000
191
220
171
194
198
150
191
1,315
10,001-50,000
112
136
116
88
126
64
89
731
50,001-100,000
6
20
15
8
14
5
6
74
>100,000
5
8
1 <
1
4
3
5
27
TOTALS
3,042
3,057
2,695
2,454
2,217
2,124
2,241
17,830
Number of TCR Routine: Minor Monitoring & Reporting Violations
Size Category
1997
1998
1999
2000
2001
2002
2003
TOTALS
<=100
1,533
1,465
1,438
1,202
998
1,037
1,005
8,678
101-500
954
895
1,171
863
542
573
598
5,596
501-1,000
208
220
260
193
127
149
144
1,301
1,001-3,300
587
604
466
513
495
465
609
3,739
3,301-10,000
256
288
216
248
244
182
291
1,725
10,001-50,000
145
167
147
101
143
75
113
891
50,001-100,000
8
25
18
10
17
5
8
91
>100,000
5
14
1
1
5
3
6
35
TOTALS
3,696
3,678
3,717
3,131
2,571
2,489
2,774
22,056
Average Number of TCR Routine: Minor Monitoring & Reporting Violations Per System
Size Category
1997 1998
1999
2000
2001
2002
2003 ;
Avg
<=100
0.015
0.015
0.015
0.013
0.011
0.011
0.011
0.013
101-500
0.022
0.020
0.027
0.020
0.012
0.013
0.014
0.018
501-1,000
0.021
0.022
0.026
0.019
0.013
0.015
0.014
0.019
1,001-3,300
0.061
0.063
0.049
0.053
0.051
0.048
0.062
0.055
3,301-10,000
0.056
0.063
0.047
0.053
0.052
0.038
0.060
0.053
10,001-50,000
0.050
0.057
0.050
0.034
0.047
0.025
0.037
0.043
50,001-100,000
0.019
0.056
0.041
0.021
0.037
0.011
0.017
0.029
>100,000
0.015
0.040
0.003
0.003
0.014
0.008
0.016
0.014
TOTALS
0.022
0.022
0.022
0.019
0.016
0.015
0.017
0.019
Percent of Systems With TCR Routine: Minor Monitoring & Reporting Violations
Size Category
1997
1998
1999
2000
2002
Avg
<=100
1.3%
1.3%
1.2%
1.0%
0.9%
1.0%
1.0%
1.1%
101-500
1.9%
1.8%
1.7%
1.5%
1.1%
1.2%
1.3%
1.5%
501-1,000
1.8%
1.9%
1.7%
1.4%
1.2%
1.3%
1.3%
1.5%
1,001-3,300
4.7%
4.5%
3.8%
4.0%
4.0%
3.6%
4.2%
4.1%
3,301-10,000
4.2%
4.8%
3.7%
4.1%
4.2%
3.1%
3.9%
4.0%
10,001-50,000
3.8%
4.7%
3.9%
2.9%
4.1%
2.1%
2.9%
3.5%
50,001-100,000
1.4%
4.5%
3.4%
1.7%
3.0%
1.1%
1.3%
2.3%
>100,000
1.5%
2.3%
0.3%
0.3%
1.1%
0.8%
1.4%
1.1%
TOTALS
1.8%
1.8%
1.6%
1.5%
nn
1.3%
1.3%
1.4%
1.5%
Page 77
-------
Exhibit H-2: Number and Frequency of TCR Routine: Minor Monitoring & Reporting
Violations by System Type: 1997 - 2003
Number of Systems With TCR Routine: Minor Monitoring & Reporting Violations
System Type 1997 : 1998 1999 2000 2001 2002 2003 TOTALS
cws
1,815
1,815
1,634
1,542
1,295
1,132
1,294
10,527
NTNCWS
253
226
216
185
183
205
178
1,446
TNCWS
974
1,016
845
727
739
787
769
5,857
TOTALS
3,042
3,057
2,695
2,454
2,217
2,124
2,241
17,830
Number of TCR
Routine:
Minor
Monitoring
& Reporting Violations
System Type
1997
1998
1999
2000
2001
2002
2003
TOTALS
CWS
2,247
2,222 s
2,452
2,066
1,505
1,305
1,629
13,426
NTNCWS
310
257
281
214
218
244
247
1,771
TNCWS
1,139
1,199
984
851
848
940
898
6,859
TOTALS
3,696
3,678
3,717
3,131
2,571
2,489
2,774
22,056
Average Number of TCR Routine: Minor Monitoring & Reporting Violations Per System
System Type
1997 ;
1998
1999
2000
2001
2002
2003
Avg
CWS
0.041
0.041
0.045
0.038
0.028
0.024
0.031
0.036
NTNCWS
0.015
0.013
0.014
0.010
0.011
0.013
0.013
0.013
TNCWS
0.012
0.013
0.010
0.009
0.009
0.011
0.010
0.011
TOTALS
0.022
0.022
0.022
0.019
0.016
0.015
0.017
0.019
Percent of Systems With TCR Routine: Minor Monitoring & Reporting Violations
System Type
1997
1998
1999
2000
2001
2002
2003
Avg
CWS
3.3%
3.3%
; 3.0%
2.9%
2.4%
2.1%
2.4%
2.8%
NTNCWS
1.3%
1.1%
1.1%
0.9%
0.9%
1.1%
0.9%
1.0%
TNCWS
1.0%
1.1%
0.9%
0.8%
0.8%
0.9%
0.9%
0.9%
TOTALS
1.8%
1.8%
1.6%
1.5%
1.3%
1.3%
1.4%
1.5%
Page 78
-------
Exhibit H-3: Number and Frequency of TCR Routine: Minor Monitoring & Reporting
Violations by Source: 1997 - 2003
Number of Systems With TCR Routine: Minor Monitoring & Reporting Violations
Source 1997 1998 1999 2000 2001 2002 2003 TOTALS
GU
42
55
39
34
51
52
52
325
GW
2,501
2,484
2,162
1,967
1,794
1,786
1,768
14,462
SW
499
518
493
453
372
285
421
3,041
TOTALS
3,042
3,057
2,695
2,454
2,217
2,124
2,241
17,830
Number of TCR Routine: Minor Monitoring & Reporting Violations
Source 1997 1998 1999 2000 2001 2002 2003 TOTALS
GU
61
63
52
41
67
75
80
439
GW
3,039
2,973
2,768
2,425
2,063
2,086
2,147
17,501
SW
596
642
896
665
441
327
547
4,114
TOTALS
3,696
3,678
3,717
3,131
2,571
2,489
2,774
22,056
Average
Number of
TCR Routine: Minor
Monitoring & Reporting Violations Per System
Source
1997
1998
1999
2000
2001
2002
2003
Avg
GU
0.151
0.131
0.102
0.068
0.070
0.071
0.074
0.095
GW
0.019
0.019
0.018
0.016
0.014
0.014
0.015
0.016
SW
0.045
0.049
0.070
0.049
0.032
0.024
0.040
0.044
TOTALS
0.022
0.022
0.022
0.019
0.016
0.015
0.017
0.019
Percent of Systems With TCR Routine: Minor Monitoring & Reporting Violations
Source
1997
1998
1999
2000
2001
2002
2003
Avg
GU
10.4%
11.5%
7.6%
5.7%
5.3%
4.9%
4.8%
7.2%
GW
1.6%
1.6%
: 1.4%
: 1.3%
1.2%
1.2%
! 1.2%
1.4%
SW
3.8%
3.9%
3.8%
3.3%
2.7%
2.1%
3.1%
3.3%
TOTALS
1.8%
1.8%
1.6%
1.5%
1.3%
1.3%
1.4%
1.5%
Page 79
-------
APPENDIX I
TCR REPEAT: MAJOR MONITORING & REPORTING VIOLATIONS OVER TIME,
BY PARAMETER
Page 80
-------
Exhibit 1-1: Frequency of TCR Repeat: Major Monitoring & Reporting Violations by
System Size: 1997 - 2003
Number of Systems With TCR Repeat: Major Monitoring & Reporting Violations
Size Category
1997
1998
1999
2000
2001
2002
2003
TOTALS
<=100
1,191
1,096
1,067
1,089
1,012
1,017
1,058
7,530
101-500
523
489
469
401
414
396
412
3,104
501-1,000
78
74
55
57
57
46
49
416
1,001-3,300
78
50
36
46
59
40
39
348
3,301-10,000
18
29
23
35
21
23
20
169
10,001-50,000
20
22
10
17
17
16
19
121
50,001-100,000
3
5
0
3
4
1 !
1
17
>100,000
3
5
2
1
9
2
4
26
TOTALS
1,914
1,770
1,662
1,649
1,593
1,541
1,602
11,731
[ Size Category
Number of TCR Repeat: Major Monitoring & Reporting Violations
^ | 2Q—
1997
1998 [ 199iT
2000
2003
TOTALS
<=100
1,406
1,301
1,196
1,234
1,143
1,140
1,163
8,583
101-500
621
588
533
452
479
437
462
3,572
501-1,000
85
82
56
64
58
50
52
447
1,001-3,300
86
58
37
50
61
41
41
374
3,301-10,000
18
30
26
40
22
23
20
179
10,001-50,000
22
23
10
18
17
16
20
126
50,001-100,000
3
5
0
5
4
1
1
19
>100,000
3
6
2
1
12
2
5
31
TOTALS
2,244
2,093
1,860
1,864
1,796
1,710
1,764
13,331
Average Number of TCR Repeat: Major Monitoring & Reporting Violations Per System
Size Category
1997
1998
1999
2000
2001
2002
2003
a vg
<=100
0.014
0.013
0.012
0.013
0.012
0.013
0.013
0.013
101-500
0.014
0.013
0.012
0.010
0.011
0.010
0.011
0.012
501-1,000
0.009
0.008
0.006
0.006
0.006
0.005
0.005
0.006
1,001-3,300
0.009
0.006
0.004
0.005
0.006
0.004
0.004
0.006
3,301-10,000
0.004
0.007
0.006
0.009
0.005
0.005
0.004
0.005
10,001-50,000
0.008
0.008
0.003
0.006
0.006
0.005
0.007
0.006
50,001-100,000
0.007
0.011
0.000
0.010
0.009
0.002
0.002
0.006
>100,000
0.009
0.017
0.006
0.003
0.034
0.005
0.014
0.012
TOTALS
0.013
0.012
0.011
0.011
0.011
0.011
0.011
0.011
Percent of Systems With TCR Repeat: Major Monitoring & Reporting Violations
Size Category
1997
1998
1999
2000
2001
2002
2003
Av9
<=100
{ 1.2% :
1.1% ;
1.1%
1.1%
1.1%
1.1%
1.2%
1.1%
101-500
1.2%
1.1%
1.1%
: 0.9%
1.0%
0.9%
1.0%
1.0%
501-1,000
0.8%
0.7%
0.5%
0.6%
0.6%
0.5%
0.5%
0.6%
1,001-3,300
0.8%
0.5%
0.4%
0.5%
0.6%
0.4%
0.4%
0.5%
3,301-10,000
0.4%
0.6%
0.5%
0.7%
0.4%
0.5%
0.4%
0.5%
10,001-50,000
i 0.7%
0.8%
0.3%
: 0.6%
0.6%
0.5%
0.6%
0.6%
50,001-100,000
0.7%
1.1%
0.0%
0.6%
0.9%
0.2%
0.2%
0.5%
>100,000
0.9%
1.4%
0.6%
0.3%
2.5%
0.5%
1.1%
1.0%
TOTALS
1.1%
1.0%
1.0%
1.0%
1.0%
1.0%
1.0%
1.0%
Page 81
-------
Exhibit 1-2: Number and Frequency of TCR Repeat: Major Monitoring & Reporting Violations by
System Type: 1997 - 2003
Number of Systems With TCR Repeat: Major Monitoring & Reporting Violations
System Type
1997 ;
1998
1999
2000
2001
2002
2003
TOTALS
cws
808 j
750
578
569
551
451
439
4,146
NTNCWS
127
137 i
164
136
152
119
123
958
TNCWS
979
883
920
944
890
971
1,040
6,627
TOTALS
1,914
1,770
1,662
1,649
1,593
1,541
1,602
11,731
Number of TCR Repeat:
Major Monitoring & Reporting Violations
System Type
1997 ;
19198
1999
2000
2001
2002
2003
TOTALS
CWS
982 ;
897
674
679
661
513
497
4,903
NTNCWS
140
152
179
143
163
127
133
1,037
TNCWS
1,122
1,044
1,007
1,042
972
1,070
1,134
7,391
TOTALS
2,244
2,093
1,860
1,864
1,796
1,710
1,764
13,331
Average Number of TCR Repeat: Major Monitoring & Reporting Violations Per System
System Type
1997 ;
1998
1999
2000
2001
2002
2003
Avg
CWS
0.018
0.016
0.012
0.013
0.012
0.010
0.009
0.013
NTNCWS
0.007
0.008
0.009
0.007
0.008
0.007
0.007
0.007
TNCWS
0.012
0.011
0.011
0.011
0.011
0.012
0.013
0.011
TOTALS
0.013
0.012
0.011
0.011
0.011
0.011
0.011
0.011
Percent of Systems With TCR Repeat: Major Monitoring & Reporting Violations
System Type
1997
1998
1999
2000
2001
2002
2003
Avg
CWS
i 1.5%
1.4%
1.1%
1.1%
1.0%
0.8%
0.8%
1.1%
NTNCWS
0.6%
0.7%
0.8%
0.7%
0.8%
0.6%
0.6%
0.7%
TNCWS
1.0%
0.9%
1.0%
1.0%
1.0%
1.1%
1.2%
1.0%
TOTALS
1.1%
1.0%
1.0%
1.0%
1.0%
1.0%
1.0%
1.0%
Page 82
-------
Exhibit 1-3: Number and Frequency of TCR Repeat: Major Monitoring & Reporting Violations by
Source: 1997 - 2003
Number of Systems With TCR Repeat: Major Monitoring & Reporting Violations
Source 1997 1998 1999 2000 2001 2002 2003 TOTALS
GU
24
37
32
24
37
26
23
203
GW
1,768
1,627
1,552
1,532
1,479
1,449
1,500
10,907
SW
122
106
78
93
77
66
79
621
TOTALS
1,914
1,770
1,662
1,649
1,593
1,541
1,602
11,731
Number of TCR Repeat: Major Monitoring & Reporting Violations
Source
1997
1998
1999
2000
2001
2002
2003
TOTALS
GU
30
48 j
40
32
46 i
31
26 i
253
GW
2,042
1,893
1,709
1,718
1,651
1,601
1,642
12,256
SW
172
152
111
114
99
78
96
822
TOTALS
2,244
2,093
1,860
1,864
1,796
1,710
1,764
13,331
Average Number of TCR Repeat: Major Monitoring & Reporting Violations Per System
Source
1997
1998
1999
2000
2001
2002
2003
Avg
GU
0.074
0.100
0.078
0.053
0.048
0.029
0.024
0.058
GW
0.013
0.012
0.011
0.011
0.011
0.011
0.011
0.011
SW
0.013
0.012
0.009
0.008
0.007
0.006
0.007
0.009
TOTALS
0.013
0.012
0.011
0.011
0.011
0.011
0.011
0.011
Percent of Systems With TCR Repeat: Major Monitoring & Reporting Violations
Source
1997
1998
1999
2000
2001
2002
2003
Av9
GU
5.9%
7.7%
6.3%
4.0%
3.9%
2.5%
2.1%
4.6%
GW
1.1%
1.0%
1.0%
1.0%
1.0%
1.0%
1.0%
1.0%
SW
0.9%
0.8%
0.6%
0.7%
0.6%
0.5%
0.6%
0.7%
TOTALS
1.1%
1.0%
1.0%
1.0%
1.0%
1.0%
1.0%
1.0%
Page 83
-------
APPENDIX J
TCR REPEAT: MINOR MONITORING & REPORTING VIOLATIONS OVER TIME, BY
PARAMETER
Page 84
-------
Exhibit J-l: Number and Frequency of TCR Repeat: Minor MR Violations by Source: 1997 - 2003
Number of Systems With TCR Repeat: Minor Monitoring & Reporting Violations
Size Category
1997
1998
1999
2000
2001
2002
2003
TOTALS
<=100
635 :
665 :
422 I
500 i
347 ;
411 :
362 ;
3,342
101-500
400 j
376 :
225 i
268 i
198 :
223 :
220 i
1,910
501-1,000
81
86;
40
63 ;
51
62;
36 *
419
1,001-3,300
66 [
75
33 I
74
48 j
52 i.
47 .
395
3,301-10,000
45
44 j
20 ]
36 :
15 ;
23 j
14 1
197
10,001-50,000
25 ^
36 :
9 I
25 i
12 j
201
16 ?
143
50,001-100,000
: 9 :
6 ;
2 !
6 :
3 :
1 i
3 ?
30
>100,000
5 j
7 j
4 f
7 j
6 j
3
5
37
TOTALS
1,266
1,295
755
979
680
795
703
6,473
Number of TCR Repeat: Minor Monitoring & Reporting Violations
Size Category
1997
1998
1999
2000
2001
2002
2003 TOTALS
<=100
707
769
452 !
567
376
449
389 j
3,709
101-500
446
458
235 5
295
209
257
246 s
2,146
501-1,000
93
104
43 >
67
55
64
41 I
467
1,001-3,300
78
101
37 /
94
54
61
51 [
476
3,301-10,000
48
60
22 j
42
15
26
14
227
10,001-50,000
27
50
9:
36
12
24
17 i
175
50,001-100,000
13
13
2;
7
4
1
3]
43
>100,000
13
21
4 I
16
6
4
...5!
69
TOTALS
1,425
1,576
804
1,124
731
886
766
7,312
Average Number of TCR Repeat: Minor Monitoring & Reporting Violations Per System
1997
1998
1999
2000
2001
2002
2003 {
Avg
<=100
0.007
0.008
0.005 j
0.006
0.004
0.005
0 004 I.
0.006
101-500
0.010
0.010
0.005 j
0.007
0.005
0.006
0.006 I
0.007
501-1,000
0009
0.010
0 004 i
0.007
0 005
0 006
0 004 I
0.007
1,001-3,300
0.008
0.011
0.004 J
0.010
0.006
0.006
0.005 |
0.007
3,301-10,000
0.010
0.013
0.005 |
0.009
0.003
0.005
0.003 s
0.007
10,001-50,000
0.009
0.017
0.003 j
0.012
0.004
0.008
0.006 ?
0.008
50,001-100,000
0.031
0.029
0.005 ;
0.015
0.009
0.002
0 006 I
0.014
>100,000
0038
0 061
0.011 :
0.045
0.017
0.011
0.014 |
0.028
TOTALS
0.008
0.009
0.005
0.007
0.004
0.005
0.005
0.006
Percent of Systems With TCR Repeat: Minor Monitoring & Reporting Violations
Size Category
1997
1998
1999
2000
2001
2002
r^rrrrr
<=100
0.6%
0.7%
0.4% j
0.5%
0.4%
0.5%
0.4%
0.5%
101-500
o.g%
0.9%
0.5% j
0.6%
0.5%
0.5%
0.5% |
0.6%
501-1,000
0.8%
0.9%
0.4% |
0.6%
0.5%
0.6%
0.4% j
0.6%
1,001-3,300
0.7%
0.8%
0.3%
0.8%
0.5%
0.5%
0.5% j
0.6%
3,301-10,000
1.0%
10%
0.4%
0.8%
0.3%
0.5%
0.3% I
0.6%
10,001-50,000
0.9%
1.2%
0.3% j
0.8%
0.4%
0.7%
0.5% |
0.7%
50,001-100,000
2.1%
1.3%
0.5% :
1.3%
0.6%
0.2%
0.6% f
1.0%
>100,000
1.5%
20%
1,1% J
1.9%
1.7%
0.8%
1.4%
1.5%
TOTALS
0.7%
0.8%
0.5%
0.6%
0.4%
0.5%
0.4%
0.6%
Page 85
-------
Exhibit J-2: Number and Frequency of TCR Repeat: Minor Monitoring & Reporting
Violations by System Type: 1997 - 2003
Number of Systems With TCR Repeat: Major Monitoring & Reporting Violations
System Type 1997 ; 1998 199£ 2000 2001 2002 2003 TOTALS
cws
563 j
608 j
304 :
476 :
332 J
328 ;
280 j
2,891
NTNCWS
I 125
122 ;
84
112
67
75 '
69;
654
TNCWS
) 578 (
565 ]
367 :
391 :
281 i
392 :
354 :
2,928
TOTALS
1,266
1,295
755
979
680
795
703
6,473
Number of TCR Repeat: Major Monitoring & Reporting Violations
System Type
1997
1998
1999
2000
2001
2002
2003
TOTALS
CWS
643 (
773 ;
332 :
550 :
357 ;
372 :
315 ;
3,342
NTNCWS
j 139 ^
141 j
87
141 i
75 j
84 j
75 j
742
TNCWS
{ 643 '
662 j
385 ;
433
299 j
430 |
376 ;
3,228
TOTALS
1,425
1,576
804
1,124
731
886
766
7,312
Average Number of TCR Repeat: Minor Monitoring & Reporting Violations PerSystem
System Type
1997
1998
1999
2000
2001
2002
2003
Avg
CWS
^ 0.012
; 0.014
< 0.006
; 0.010
: 0.007
0.007 i
0.006 :
0.009
NTNCWS
1 0007
i 0 007
I 0 004
i 0.007
; o.oo4
: 0.004
0.004 :
0.005
TNCWS
; 0.007
j 0.007
! 0.004
: 0.005
i 0.003
0.005
0.004 |
0.005
TOTALS
0.008
0.009
0.005
0.007
0.004
0.005
0.005
0.006
Percent
of Systems
With TCR
Repeat:
Major Monitoring & Reporting Violations
System Type
1997
: 1998
1999
2000
2001
2002
2003
Avg
CWS
J 1.0%
| 1.1%
: o.6%
0.9%
: 0.6%
0.6%
0.5% j
0.8%
NTNCWS
i 0.6%
5 0.6%
; 0.4%
i 0.5%
O.S%
0.4%
0.4% !
0.5%
TNCWS
0.6%
| 0.6%
0.4%
04 %
I 0.3%
' 0.4%
04% !
0.5%
TOTALS
0.7%
0.8%
0.5%
0.6%
0.4%
0.5%
0.4%
0.6%
Page 86
-------
Exhibit J-3: Number and Frequency of TCR Repeat: Minor Monitoring & Reporting Violations
by Source: 1997 - 2003
Number of Systems With TCR Repeat: Minor Monitoring & Reporting Violations
Source 1997 1998 1999 2000 2001 2002 ; 2003 TOTALS
GU
39 :
59 :
11 ;
30 :
16
38
19 :
212
GW
1,145 i
1,153
651 !
799
608
706
638
5,700
SW
82 ;
83 ¦
93 :
150 i
56
51
46 ;
561
TOTALS
1,266
1,295
755
979
680
795
703
6,473
Number of TCR Repeat: Minor Monitoring & Reporting Violations
Source
1998 i
1999 [
2000 [
2001
2002
TOTALS
GU
53 j
00
cn
12 j
38 ;
18
46
26 :
278
GW
1,274 :
1,378 :
692 :
884 :
653
785
692 ;
6,358
SW
98 '
113 :
100 :
202 ;
60
55
48 :
676
TOTALS
1,425
1,576
804
1,124
731
886
766
7,312
Average Number of TCR Repeat: Minor Monitoring & Reporting Violations Per System
i Source
1:997
1998
| 1999
2000
i 2001 |
2002
! 2003 I
Avg
i GU
: 0.131 !
0.177
i 0.024
i 0.063
: 0.019 i
0.043
I 0.024 :
0.069
: GW
0.008
0.009
! 0.004
0.006
i 0.004 '
0.005
j 0.005
0.006
: SW
; o.oo7 i
0.009
; 0.008
0.015
! 0.004 I
0.004
i 0.004 ¦
0.007
TOTALS
0.008
0.009
0.005
0.007
0.004
0.005
0.005
0.006
Percent of Systems With TCR Repeat: Minor Monitoring & Reporting Violations
Source
1997
1998
1999
2000
2001
2002
2003
Avg
GU
: 9.7% :
12.3%
: 2.2% :
5.0% !
1.7%
! 3.6% |
" 1-8%
5.2%
GW
; 0.7% :
0.7%
: 0.4% !
0.5% :
0.4%
: 0.5% !
! 0.4% i
0.5%
SW
i 0.6% :
0.6%
: 0.7% :
1.1% :
0.4%
: 0.4% |
i 0.3% ;
0.6%
TOTALS
0.7%
0.8%
0.5%
0.6%
0.4%
0.5%
0.4%
0.6%
Page 87
-------
APPENDIX K
STATISTICAL ANALYSIS AND OBSERVATIONS OF TCR VIOLATION DATA
Page 88
-------
Initial Statistical Analysis of TCR Violations Data
Summary
Although EPA explores statistical testing in this paper, the paper concentrates on
presenting the data, as it is, in SDWIS/FED. The statistical analysis of the TCR compliance data that
are outlined in this appendix consists of comparisons of the data across categories using Chi-square
tests on the relationships between the seven varieties of TCR violations and system size class, system
type, and system source water. This resulted in 147 Chi-square tests, for 7 varieties of TCR violations
x 3 ways of categorizing systems x 7 different years of data. Nearly all of these 147 tests indicated
that system characteristics had a highly statistically significant impact on violations rate. However,
these test results only indicate confidence that each system characteristic (size class, type, water
source) has some impact on violation rates, but the results do not indicate what these specific impacts
are.
Impact of system size class on violations rate:
Total and Monthly MCL violations:
• Middle size classes (3,301-50,000) > violations relative to other size classes.
• Larger size classes (>50,001) < violations relative to other size classes.
Acute MCL violations:
• Smaller size classes (101-500) > violations relative to other size classes.
• Middle size classes (1,001-10,000) < violations relative to other size classes.
Routine Major and Repeat Major violations:
• Smallest size class (<100) > violations relative to other size classes.
• Middle and large size classes (>501) < violations relative to other size classes.
Routine Minor and Repeat Minor violations:
Smallest size class (<100) ^violations relative to other size classes.
Impact of system type on violations rate:
Total and Monthly MCL violations:
• CWS > violations relative to other system types.
• TNCWS < violations relative to other system types.
Routine Major violations:
• CWS < violations relative to other system types.
• TNCWS > violations relative to other system types.
Page 89
-------
Routine Minor and Repeat Minor violations:
• CWS > violations relative to other system types.
• NTNCWS and TNCWS < violations relative to other system types.
Impact of water source on violations rate:
Total and Monthly MCL violations
• SW < violations relative to other water sources.
Acute MCL violations
• GU and SW > violations relative to other water sources.
• GW < violations relative to other water sources.
Routine Major and Repeat Major violations:
• GU > violations relative to other water sources.
• SW < violations relative to other water sources.
Routine Minor and Repeat Minor violations:
• GU > violations relative to other water sources.
• GW < violations relative to other water sources.
Page 90
-------
I. Chi-square test results
The following analyses have been performed on the percentage of systems that have had
TCR violations of various sorts. This data:
• Covers seven varieties of TCR violations: 1) Total MCL violations; 2) Acute MCL
violations; 3) Monthly MCL violations; 4) Routine Major Monitoring & Reporting/reporting
violations; 5) Routine Minor Monitoring & Reporting/reporting violations; 6) Repeat Major
Monitoring & Reporting/reporting violations; 7) Repeat Minor Monitoring & Reporting/reporting
violations.
• Are available for each of the seven years from 1997 through 2003.
• Has been broken down in each of three ways: 1) By system size class; 2) By system type
(i.e., CWS, NTNCWS, TNCWS); 3) By water source (e.g., GU, GW, SW).
In effect, then, there are 147 tables of data: one table for each of the seven varieties of
TCR violations, for each of seven years, and for each of three ways to break out the data
(7x7x3=147). Each table shows, for a given variety of TCR violation and year, the number and
percentage of systems of different sorts that did and did not have this variety of violation. Please refer
to Exhibit K-l as an example.
Exhibit K-l: TCR Violations Data for
Type of Violation: Total MCL
Year: 2003
Break-Out: By water source
Water
Source
# Systems
w/MCL
Violations
# Systems w/out MCL
Violations
Total #
Systems
% Systems w/MCL
Violations
GU
62
1,023
1,085
5.7
GW
6,669
139,799
146,468
4.6
SW
371
13,277
13,648
2.7
All
7,102
154,099
161,201
4.4
The initial question to answer for this table of data is whether "Water Source" makes a
difference in the likelihood of a system having an MCL violation. In 2003, 4.4 % of all systems had
MCL violations. GU and GW systems had MCL violations more frequently than this average, while
SW systems had MCL violations less frequently than this average. Are these differences statistically
significant?
A Chi-square (%2) test was performed to answer this question. In formal terms, a Chi-
square test allows one to assess the confidence with which one can reject a "null hypothesis" to the
effect that there is no difference across the three water sources in the frequency with which systems
have MCL violations. The Chi-square value calculated for this table of data is 104.24, resulting in at
least 99.9% confidence that the MCL violation rate is not constant across the three sets of systems
using the different water sources. In effect, the differences among the violation rates for systems
using the three different sorts of source waters are statistically significant.
Page 91
-------
Note that the Chi-square test result indicates confidence that water source has an impact
on violation rates, but the test tells nothing about what that specific impact is. One can't, for example,
conclude that GU systems have a higher probability of incurring MCL violations than GW systems,
and that GW systems in turn have a higher probability of incurring MCL violations than SW systems.
To draw more specific conclusions, additional statistical tests are needed other than this initial Chi-
square.
The results of the 147 Chi-square tests are shown in following three summary tables.
Exhibit K-2 shows the Chi-square test results evaluating whether system size class has an impact on
violation rates, Exhibit K-3 shows results evaluating the impact of system type on violation rates, and
Exhibit K-4 shows results evaluating the impact of water source on violation rates. The tables show
the x2 value and the probability that such a value could arise by chance given the null hypothesis that
the variable under consideration (size class in Exhibit K-2, type of system in Exhibit K-3, and water
source in Exhibit K-4) has no impact on the TCR violation rate. The probabilities (p values) less than
0.05 are considered statistically significant. In such a case, there is less than a 5% likelihood that the
variable under consideration has no impact on the TCR violations rate and the observed variation in
TCR violations rate across systems is due to chance alone. Or, from another perspective, when the p
value is less than 0.05 there is more than a 95% likelihood that the variable under consideration does
have some impact on the TCR violations rate. If the p-value is greater than 0.05, it is not considered
statistically significant, and "n.s." (not significant) is recorded in the table.
Exhibit K-2. Results of %2 tests on violations data, by size of system, 1997-2003
Total MCL
Acute MCL
Monthly MCL
Routine Maior
Routine Minor
Reoeat Maior
Reoeat Minor
%2
p value
%2
p value
%2
p value
%2
p-value
%2
p-value
%2
p-value
%2
p-value
2003
58.05
<0.001
18.25
p<0.025
59.99
p<0.001
2017.11
p<0.001
959.23
p<0.001
117.92
p<0.001
20.53
p<0.01
2002
45.23
<0.001
10.85
n.s.
48.40
p<0.001
2309.53
p<0.001
589.35
p<0.001
104.88
p<0.001
10.32
n.s
2001
32.86
<0.001
43.73
p<0.001
38.52
p<0.001
1622.03
p<0.001
1123.92
p<0.001
70.70
p<0.001
25.53
p<0.001
2000
31.37
<0.001
37.08
p<0.001
36.89
p<0.001
1871.4
p<0.001
824.55
p<0.001
78.02
p<0.001
34.41
p<0.001
1999
28.73
<0.001
39.71
p<0.001
26.37
p<0.001
2469.89
p<0.001
652.52
p<0.001
102.55
p<0.001
12.38
n.s
1998
72.55
<0.001
69.72
p<0.001
88.24
p<0.001
1224.10
p<0.001
940.02
p<0.001
51.23
p<0.001
36.29
p<0.001
1997
79.94
<0.001
56.74
p<0.001
138.29
p<0.001
1529.04
p<0.001
810.03
p<0.001
54.32
p<0.001
51.67
p<0.001
Exhibit K-3. Results of x2 tests on violations data, by type of system, 1997-2003
Total MCL
Acute MCL
Monthly MCL
Routine Maior
Routine Minor
Reoeat Maior
Reoeat Minor
%2
p-value
%2
p-value
%2
p-value
%2
p-value
%2
p-value
%2
p-value
%2
p-value
2003
4.89
n.s.
19.51
p<0.001
7.20
p<0.05
1811.92
p<0.001
623.11
p<0.001
74.11
p<0.001
15.39
p<0.001
2002
32.91
p<0.001
9.23
p<0.01
44.21
p<0.001
1888.43
p<0.001
400.75
p<0.001
43.8
p<0.001
24.3
p<0.001
2001
117.99
p<0.001
33.33
p<0.001
118.06
p<0.001
1408.12
p<0.001
688.93
p<0.001
11.20
p<0.01
83.18
p<0.001
2000
160.71
p<0.001
80.58
p<0.001
132.01
p<0.001
1115.71
p<0.001
1071.00
p<0.001
25.36
p<0.001
125.93
p<0.001
1999
167.19
p<0.001
15.25
p<0.001
190.26
p<0.001
2034.14
p<0.001
1021.87
p<0.001
9.90
p<0.01
23.17
p<0.001
1998
383.23
p<0.001
0.56
n.s.
427.30
p<0.001
116.79
p<0.001
1080.75
p<0.001
99.93
p<0.001
135.88
p<0.001
1997
288.27
p<0.001
11.08
p<0.01
379.24
p<0.001
406.01
p<0.001
1091.17
p<0.001
114.73
p<0.001
90.61
p<0.001
Exhibit K-4. Results of x2 tests on violations data, by source, 1997-2003
Total MCL
Acute MCL
Monthly MCL
Routine Maior
Routine Minor
Reoeat Maior
Reoeat Minor
%2
p-value
%2
p-value
%2
p-value
%2
p-value
%2
p-value
%2
p-value
%2
p-value
2003
104.24
p<0.001
34.02
p<0.001
123.55
p<0.001
339.61
p<0.001
413.31
p<0.001
39.23
p<0.001
46.30
p<0.001
2002
83.66
p<0.001
47.01
p<0.001
104.10
p<0.001
506.49
p<0.001
182.18
p<0.001
57.91
p<0.001
211.25
p<0.001
2001
72.83
p<0.001
160.20
p<0.001
104.21
p<0.001
360.38
p<0.001
333.40
p<0.001
108.40
p<0.001
37.27
p<0.001
2000
29.68
p<0.001
319.10
p<0.001
92.23
p<0.001
414.83
p<0.001
442.73
p<0.001
68.62
p<0.001
276.80
p<0.001
1999
70.65
p<0.001
464.10
p<0.001
61.78
p<0.001
376.44
p<0.001
560.41
p<0.001
165.01
p<0.001
57.10
p<0.001
1998
196.77
p<0.001
428.30
p<0.001
128.20
p<0.001
555.04
p<0.001
638.43
p<0.001
214.52
p<0.001
850.30
p<0.001
1997
201.90
p<0.001
347.60
p<0.001
129.94
p<0.001
655.21
p<0.001
502.25
p<0.001
89.40
p<0.001
438.79
p<0.001
Page 92
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It is apparent in virtually all cases that the differences in TCR violation rates across groups of
systems are statistically significant - whether systems are broken out by size class, by type, or by water
source. Of the 147 Chi-square tests shown in these three tables, 142 are significant at the 0.05 level or
lower, and 135 are significant at the 0.001 level or lower. System size, type and source water clearly
have some impact on violation rates. Again, though, these Chi-square tests serve only to demonstrate that
there is a statistically significant relationship or relationships between system characteristics and TCR
violations rate, but further investigation is needed to determine exactly what these relationships might be.
Although Chi-square tests make up the bulk of the statistical tests, EPA also explored the use of
odds ratio as an alternate form of statistical testing. For example, based on RR, EPA cannot reject the
notion that ^' V'°^ ^ =\ \ 95% confidence interval for RR is [0.984, 1.6], Combining GU and
?x\vioI | (IWJ
GW, it is possible to reject that I notSW] _ ^ ^ conf1(jence interval is [1.514, 1.86], EPA
Prjvz'o/ | SW}
went with the Chi-square test because observed violation numbers seem sufficiently large to justify the
test. Textbook examples and NIST's handbook often have smaller numbers
(http: //www. itl. ni st. gov/di v898/handb 00k/).
II. Observations regarding system characteristics and TCR violation rates that are consistent over
time.
Observations Regarding Consistency over Time for relationship between Systems Size and Violation
Rate:
• Total MCL and Monthly MCL violations: a higher proportion of systems in the middle
size classes (3,301-50,000) incur violations relative to systems in other size classes. A smaller
proportion of systems in the larger size classes (>50,000) incur violations than do systems in
other size classes.
• Acute MCL violations: a higher proportion of systems in the small size class (101-500)
incur violations relative to systems in other size classes. A smaller proportion of systems in the
middle size classes (1,001-10,000) incur violations than do systems in other size classes.
• Routine Major and Repeat Major violations: systems in the smallest size class (<100)
incur them with higher frequency relative to all other systems, while systems in the middle and
large size classes (>500) incur them with relatively lower frequency.
• Routine Minor and Repeat Minor violations: systems in the smallest size class (<100)
incur them with relatively lower frequency.
Observations Regarding Consistency over Time for relationship between System Type and
Violation Rate:
• Total and Monthly MCL violations: a higher proportion of CWS incur violations relative
to other systems. A smaller proportion of TNCWS incur violations relative to other systems.
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• Routine Major violations: CWS incur violations with relatively lower frequency, and
TNCWS incur them with relatively higher frequency.
• Routine Minor and Repeat Minor violations: CWS incur violations more frequently than
do other systems, while NTNCWS and TNCWS incur them less frequently than do other
systems.
Observations Regarding Consistency over Time for relationship between Systems Source and
Violation Rate:
• Total and Monthly MCL violations: a higher proportion of GU systems incur violations
relative to other systems. A smaller proportion of SW systems incur violations than do other
systems.
• Acute MCL violations: a higher proportion of GU and SW systems incur violations
relative to other systems. A smaller proportion of GW systems incur violations than do other
systems.
• Routine Major and Repeat Major violations: GU and GW systems incur them with
relatively higher frequency, and SW systems incur them with relatively lower frequency.
• Routine Minor and Repeat Minor violations: GU systems again incur these violations
relatively frequently. GW system incur them relatively infrequently.
IV. Observations Regarding the relationship between season and the number of acute MCL
violations for each system type.
Climate can have a large impact on microbial growth and contamination. For example, warmer
temperatures and an increase in precipitation events can lead to higher microbial growth rates. To
determine whether seasonality has an effect on acute MCL violations, we examined the number of acute
MCL violations for each month, FY 1997- FY 2003, as shown in Exhibit 22. Initial examination of the
data suggested that the highest amount of acute MCL violations occurred during the months with the
warmest weather.
While climate is one potential factor that could be driving this trend, water usage patterns may also
influence the number of violations in a warm month. For example, TNCWS generally have higher use
during the summer since they are typically associated with vacation areas. An increase in violations is
more likely when there is greater water usage and sampling.
To examine the impact of seasonality in systems that have consistent usage (e.g. CWS), and those
that have fluctuating usage (e.g. TNCWS), we examined the number of acute MCL violations by system
type. Additionally, we defined four seasons: 1) Winter (December through February), 2) Spring (March
through May), 3) Summer (June through August), and 4) Fall (September through November). For each
season and each system type, we calculated the percent of violations that accrued during each season. For
example, there were a total of 1129 acute violations during the winter season (December through
February) for CWS. The total number of acute violations for CWS systems from FY 1997- FY 2003 was
5219. Therefore, for CWS systems, 21.6% (1129 / 5219) of all acute violations from 1997-2003 occurred
Page 94
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during the winter season. Exhibit-KlO describes the seasonal distribution of acute MCL Violations for
CWS, NTNCWS, and TNCWS systems.
Exhibit K-5: Percent of Acute MCL Violations that Occur Each Season for Each System Type
45.0%
(A
C
o
+¦»
TO
O
>
_l
o
D
o
<
c
0)
o
5
D.
40.0%
35.0%
30.0%
25.0%
20.0%
15.0%
10.0%
5.0%
0.0% -
CWS
NTNCWS
TNCWS
~ Winter
21.6%
17.7%
13.3%
ID Spring
17.8%
17.8%
21.2%
¦ Summer
31.5%
33.3%
39.8%
~ Fall
29.1%
31.2%
25.7%
Our preliminary assessment of the data revealed the following trends:
• Summer has the highest percentage of acute MCL violations for all system types.
• The difference between summer vs. spring and summer vs. winter is much more
pronounced than the difference between summer vs. fall, especially for CWS and NTNCWS
systems.
For all water systems, the percent of acute MCL violations in summer was greater than in spring or in
winter. The percent of acute violations in summer was greater for TNCWS (39.8%) than for NTNCWS
and CWS (33.3 and 31.5 %, respectively). This could in part be due to the fact that transient, non-
community systems are typically associated with vacation areas, which has a higher proportion of use
and water quality testing in summer than in other seasons. On the other hand, NTNCWS and CWS have
a more uniform distribution of usage and testing among the seasons. Climate is another important
variable that may be driving this patterns, as higher temperatures and precipitation rates generally occur
from June-September. This climate effect is most strongly supported by the fact that NTNCWS and
CWS have a higher percentage of violations in summer, but fairly consistent usage rates throughout the
year, which removes the effect of increase usage in the summer that is associated with TNCWS systems.
The percent of acute violations was greater in summer than fall for all system types, however this
difference was only statistically significant for TNCWS systems, which had a difference of 14.1%. For
NTNCWS and CWS systems, there was only a difference of 2.1% and 2.4%, respectively.
Page 95
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APPENDIX L
ANALYSIS OF REPEAT VIOLATIONS BY SYSTEM TYPE, SOURCE, AND SYSTEM SIZE
Page 96
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Exhibit L-l: Percent of Systems With Acute Violations In A Given Number of Years
By Type of System
Number of Systems With At Least 1 Acute Violation: 6,483
rr
1
2
3
4
5
6
7
~ cws
81.9%
8.1%
3.0%
2.6%
4.1%
0.3%
0.0%
¦ NTNCWS
82.8%
13.5%
2.8%
0.6%
0.1%
0.1%
0.0%
~ TNCWS
83.0%
13.2%
2.9%
0.7%
0.1%
0.0%
0.0%
Number of Years With An Acute Violation
A higher percentage of CWSs had Acute violations in 6 of 7 years.
No TNCWSs had Acute violations in 6 of 7 years.
Over twice as many CWSs have chronic Acute violations (violations in 3 or more years) than
NTNCWSs and TNCWSs.
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Exhibit L-2: Percent of Systems With Monthly Violations In A Given Number of Years
By Type of System
>- 40%
Number of Systems With At Least 1 Monthly Violation: 33,586
~CL
L
1
2
3
4
5
6
7
~ cws
67.2%
20.6%
7.7%
2.9%
1.1%
0.4%
0.2%
¦ NTNCWS
73.8%
19.7%
4.8%
1.3%
0.4%
0.0%
0.0%
~ TNCWS
76.3%
17.7%
4.5%
1.1%
0.3%
0.0%
0.0%
Number of Years With A Monthly MCL Violation
A higher percentage of CWSs had Acute violations in 6 of 7 years or in all 7 years.
- No TNCWSs or NTNCWSs had Acute violations in 6 of 7 years or in all 7 years.
Approximately twice as many CWSs have chronic Acute violations (violations in 3 or more
years) than NTNCWSs and TNCWSs.
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Exhibit L-3: Percent of Systems With Acute Violations In A Given Number of Years
By System Size
100% ^
FT
80%
70%
60%
50%
40%
30%
20%
10%
0% -
-
Number of Systems With At Least 1 Acute Violation: 6,483
1 l7®*1! in
—™ m
1
2
3
4
5
6
7
~ <=100
84.2%
11.9%
2.6%
0.7%
0.6%
0.1%
0.0%
¦ 101-500
79.6%
12.4%
3.7%
1.9%
2.2%
0.2%
0.0%
¦ 501 -1,000
82.8%
8.3%
4.7%
2.5%
1.7%
0.0%
0.0%
H 1,001-3,300
87.4%
6.3%
2.4%
2.4%
1.6%
0.0%
0.0%
~ 3,301-10,000
92.7%
4.9%
0.8%
0.8%
0.8%
0.0%
0.0%
~ 10,001-50,000
91.8%
5.9%
1.2%
1.2%
0.0%
0.0%
0.0%
~ 50,001-100,000
95.0%
5.0%
0.0%
0.0%
0.0%
0.0%
0.0%
~ >100,000
87.5%
7.5%
2.5%
2.5%
0.0%
0.0%
0.0%
Number of Years With An Acute Violation
Only systems in the two smallest size categories had Acute violations in 6 of 7 years.
The highest rate of chronic violators (Acute violations in 3 or more years) are in the 101-500,
501-1,000 and 1,001-3,300 size categories.
Page 99
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Exhibit L-4: Percent of Systems With Monthly Violations In A Given Number of Years
By System Size
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
Number of Systems With At Least 1 Monthly Violation: 33,586
r-TsTTHfil
6
7
74.7%
72.8%
18.6%
18.4%
5.0%
5.9%
1.3%
1.9%
0.4%
0.7%
0.0%
0.2%
0.0%
0.1%
1501-1,000
74.3%
17.6%
4.6%
2.2%
0.9%
0.3%
0.1%
H 1,001-3,300
~ 3,301-10,000
B 10,001-50,000
71.4%
72.7%
68.7%
20.0%
16.9%
19.3%
5.9%
7.2%
7.1%
1.6%
2.4%
2.3%
0.6%
0.8%
1.5%
0.3%
0.1%
0.7%
0.2%
0.0%
0.4%
~ 50,001-100,000
83.3%
6.3%
!.3%
2.1%
0.0%
0.0%
0.0%
~ >100,000
81.7%
9.6%
5.3%
2.4%
1.0%
0.0%
0.0%
Number of Years With A Monthly Violation
Page 100
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Exhibit L-5: Percent of Systems With Acute Violations In A Given Number of Years
By Source
Number of Systems With At Least 1 Acute Violation: 6,483
IBBBBBBBBB&ftMflWil ..
1
2
3
4
5
6
7
~ sw
61.8%
15.6%
7.3%
5.5%
9.0%
0.8%
0.0%
¦ GW
85.4%
11.1%
2.3%
0.7%
0.4%
0.0%
0.0%
¦ GU
70.0%
17.7%
6.9%
3.8%
1.5%
0.0%
0.0%
Number of Years With An Acute Violation
Page 101
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Exhibit L-6: Percent of Systems With Monthly Violations In A Given Number of Years
By Source
80% t
Number of Systems With At Least 1 Monthly Violation: 33,586
1
2
3
4
5
6
7
~ sw
75.4%
14.9%
4.6%
2.5%
1.6%
0.6%
0.4%
¦ GW
72.6%
19.2%
5.7%
1.7%
0.5%
0.1%
0.0%
¦ GU
72.3%
18.5%
7.6%
0.8%
0.8%
0.0%
0.0%
Number of Years With A Monthly MCL Violation
Page 102
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