DRAFT − Occurrence Data 

from the Second Unregulated 

Contaminant Monitoring 

Regulation (UCMR 2)
Office of Water (4607M)

EPA-815-R-14-004

April 2014

www.epa.gov/safewater
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

iii

Executive Summary

This report presents the United States Environmental Protection Agency’s (EPA) analysis 

of the national occurrence of unregulated contaminants that were monitored in public water 

systems (PWSs) under the second Unregulated Contaminant Monitoring Regulation (UCMR 2). 

The UCMR 2 monitoring was conducted for selected unregulated contaminants in drinking water 

under the authority of Section 1445(a)(2) of the Safe Drinking Water Act (SDWA), as amended 

in 1996. Also presented in this report are an overview of the regulatory background for 

unregulated contaminant monitoring, the design and implementation of the UCMR 2 monitoring 

program, data management and quality assurance/quality control (QA/QC), and the occurrence 

measures used and any limitations of those measures.

The UCMR program specifies a three-tiered approach for contaminant monitoring based 

on the availability of analytical methods and contaminant prioritization. Assessment Monitoring 

(List 1) is the largest in scope of the three monitoring components (or tiers). Assessment 

Monitoring contaminants are the priority contaminants for which analytical methods are well

established. Screening Survey (List 2) monitoring primarily targets contaminants with analytical 

methods that were recently developed and are not yet widely used. Pre-Screen Testing (List 3) is 

for limited and targeted monitoring of contaminants that require analytical methods that may 

utilize specialized testing equipment. The Pre-Screen Testing provisions of the UCMR program 

were not required under UCMR 2.

The UCMR 2 program specified that all large (serving 10,001 – 100,000 people) and very 

large (serving more than 100,000 people) community water systems (CWSs) and non-transient 

non-community water systems (NTNCWSs), plus a statistically representative national sample of 

800 small (serving 10,000 or fewer people) CWSs and NTNCWSs were required to monitor for 

the 10 Assessment Monitoring contaminants. Additionally, UCMR 2 required monitoring of the 

15 Screening Survey contaminants by all very large systems, 320 selected large systems, and 480 

selected small systems.

The UCMR 2 sampling was conducted from January 2008 to December 2010. The data

were collected from PWSs in all 50 states and 6 additional primacy entities. All of the applicable

PWSs participated in the UCMR 2 monitoring, and collectively the systems submitted 

monitoring data of high quality. The UCMR 2 Data Quality Objectives (DQOs) that required: (1)

a small systems participation rate of at least 82.375% and, (2) at least 90% of all submitted data 

meet the established data acceptance criteria were both surpassed.

EPA developed a two-stage analytical approach to evaluate the UCMR 2 contaminant 

occurrence data. In Stage 1, the data are first reviewed, quality-checked, and characterized, and 

then analyzed to generate simple, clear non-parametric estimates of contaminant occurrence. For 

example, simple counts are made of the number of systems, and populations served by those 

systems, with at least one observed detection that has a concentration greater than the HRL,

greater than 1⁄2 the HRL, or greater than or equal to the Minimum Reporting Level (MRL). Based 

on the Stage 1 analysis, any contaminant found to have significant occurrence can be analyzed 

with a more rigorous Stage 2 analysis. In Stage 2, statistical modeling is used to generate 

national probability estimates of contaminant occurrence based on estimated annual (or longer-
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

iv

term) mean concentrations of contaminants along with statistical measures of uncertainty and 

error. This report presents the Stage 1 analysis only.

Occurrence measures are presented for different categories of systems so that occurrence 

can be assessed based on system characteristics such as source water type or system size. Given 

that ground water systems and surface water systems have different sampling schedules, it is 

important to evaluate occurrence separately for the two source water types. EPA has also 

evaluated contaminant occurrence separately for the different UCMR 2 system size categories. A 

census of large and very large systems, plus a sample of small systems, monitored for 10 

Assessment Monitoring contaminants. A census of very large systems, plus a statistical sample 

of large and small systems monitored for 15 Screening Survey contaminants. UCMR 2

occurrence data from the large and very large systems that monitored for the Assessment 

Monitoring contaminants; and from very large systems that monitored for the Screening Survey 

contaminants support contaminant occurrence analyses that are representative (statistically valid) 

at the state level. The statistical samples of small systems were insufficient to support a 

statistically rigorous state-level occurrence analysis; however, summary (appendix) tables of all 

UCMR 2 monitoring results are presented for each state, territory, and tribe to provide a 

complete record of monitoring results by state.

In the final UCMR 2 data set, an average of 32,148 samples from 4,140 PWSs were 

collected for each of 10 Assessment Monitoring contaminants. Only 2 of the 10 Assessment 

Monitoring contaminants were detected – RDX and terbufos sulfone. Four detections of RDX

(ranging from 1 μg/L to 1.1 μg/L) were reported; none of these detections were greater than the 

HRL of 21 μg/L. One detection of terbufos sulfone was reported; this detection (equal to 

0.42 μg/L) was greater than the HRL of 0.35 μg/L. The remaining eight Assessment Monitoring 

contaminants (BDE-47, BDE-99, BDE-100, BDE-153, dimethoate, 1,3-dinitrobenzene, HBB, 

and TNT) were not detected.

In the final UCMR 2 data set, an average of 11,169 samples from 1,198 PWSs were 

collected for each of the nine acetanilide parent and degradate herbicides monitored under the 

Screening Survey. An average of 18,101 samples from 1,198 PWSs were collected for each of 

the six nitrosamines monitored under the Screening Survey. Ten of the 15 Screening Survey 

contaminants were detected – acetochlor ESA, alachlor ESA, metolachlor, metolachlor ESA, 

metolachlor OA, NDBA, NDEA, NDMA, NMEA, and NPYR. UCMR 2 monitoring found no 

analytical detections for five Screening Survey contaminants (acetochlor, acetochlor OA, 

alachlor, alachlor OA, and NDPA). Of the 10 Screening Survey contaminants detected, 7 

contaminants had at least one detection greater than their respective HRLs – acetochlor ESA, 

alachlor ESA, NDBA, NDEA, NDMA, NMEA, and NPYR. By far, the contaminant with the 

most detections was NDMA. NDMA was detected in 1,861 samples reported from 324 PWSs. 

NDMA detections ranged from 0.002 μg/L to 0.63 μg/L. All detections were greater than 

NDMA’s HRL of 0.0006 μg/L.

To meet agency deadlines in the deliberative process for Regulatory Determination 3, 

data submitted through June 2011 were used as the basis for occurrence analyses under that 

effort. Appendix D of this document presents the June 2011 data snapshot. The June 2011 data 

are only slightly different from the final December 2011 UCMR 2 data set described in the body 

of this report.
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

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Contents

Executive Summary.......................................................................................................................iii

Contents.......................................................................................................................................... v

Exhibits......................................................................................................................................... vii

Acronyms....................................................................................................................................... ix

1 Introduction.................................................................................................................. 1

1.1 Regulatory Background ............................................................................................... 2

1.2 Two-Stage Analytical Approach.................................................................................. 3

1.3 Analytical Tools........................................................................................................... 4

2 UCMR 2 Program Overview ....................................................................................... 5

2.1 UCMR 2 Monitoring Design and Contaminant List.................................................... 5

2.2 Assessment Monitoring................................................................................................ 8

2.3 Screening Survey ......................................................................................................... 9

3 UCMR 2 Data Description......................................................................................... 11

3.1 Data Submittal Process .............................................................................................. 12

3.2 Data Management and Quality Assurance................................................................. 12

3.3 Assessments of Data Representativeness and Completeness..................................... 15

3.3.1 Data Representativeness............................................................................................. 15

3.3.2 Completeness ............................................................................................................. 16

3.4 Additional Data Management Considerations........................................................... 16

3.4.1 Population Adjustments............................................................................................. 17

3.4.2 Temporal Information ................................................................................................ 17

4 Description of Stage 1 Analytical Method................................................................. 18

4.1 Stage 1 Analysis......................................................................................................... 18

4.2 Threshold Evaluations................................................................................................ 19

4.3 Additional Considerations for Stage 1 Analysis........................................................ 20

4.3.1 Ground Water and Surface Water Comparisons........................................................ 20

4.3.2 Large System and Small System Totals..................................................................... 20

4.3.3 Extrapolation of the Results....................................................................................... 21

4.3.4 Stage 1 Analyses and the Statistically-Weighted Sample of Small Systems............. 22

5 Stage 1 Occurrence Estimates.................................................................................... 24

5.1 Assessment Monitoring Contaminants ...................................................................... 27

5.1.1 RDX ........................................................................................................................... 27

5.1.2 Terbufos Sulfone........................................................................................................ 28

5.2 Screening Survey Contaminants with Detections...................................................... 32

5.2.1 Acetochlor ESA ......................................................................................................... 32

5.2.2 Alachlor ESA ............................................................................................................. 36

5.2.3 Metolachlor ................................................................................................................ 40

5.2.4 Metolachlor ESA........................................................................................................ 42

5.2.5 Metolachlor OA ......................................................................................................... 43
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

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5.2.6 NDBA ........................................................................................................................ 45

5.2.7 NDEA......................................................................................................................... 48

5.2.8 NDMA........................................................................................................................ 52

5.2.9 NMEA........................................................................................................................ 56

5.2.10 NPYR......................................................................................................................... 60

6 References.................................................................................................................. 64
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Exhibits

Exhibit 2-1: Contaminants Monitored Under UCMR 2 ................................................................. 5

Exhibit 2-2: Number of PWSs that Monitored Under UCMR 2 .................................................. 10

Exhibit 3-1: UCMR 2 Required Data Elements ........................................................................... 13

Exhibit 4-1: Minimum Reporting Levels (MRLs) and Health Reference Levels (HRLs) 

for UCMR 2 Contaminants............................................................................................... 19

Exhibit 4-2: Example Calculation of National Estimates (Extrapolations) for UCMR 2 Small and 

Large Systems (serving ≤ 100,000 people) for Screening Survey Contaminants ............ 22

Exhibit 5-1: Summary of Stage 1 Occurrence Results for 10 Assessment Monitoring 

Contaminants and 15 Screening Survey Contaminants.................................................... 25

Exhibit 5-2: Summary of Stage 1 Occurrence Results for 10 Assessment Monitoring 

Contaminants and 15 Screening Survey Contaminants.................................................... 26

Exhibit 5-3: RDX National Occurrence Measures from UCMR 2 Assessment Monitoring Data -

Summary of System and Population Served Data - All Detections.................................. 27

Exhibit 5-4: Terbufos Sulfone National Occurrence Measures from UCMR 2 Assessment 

Monitoring Data - Summary of System and Population Served Data - All Detections ... 29

Exhibit 5-5: Terbufos Sulfone National Occurrence Measures from UCMR 2 Assessment 

Monitoring Data - Summary of System and Population Served Data - Detections > 1⁄2 

HRL................................................................................................................................... 30

Exhibit 5-6: Terbufos Sulfone National Occurrence Measures from UCMR 2 Assessment 

Monitoring Data - Summary of System and Population Served Data - Detections > HRL

........................................................................................................................................... 31

Exhibit 5-7: Acetochlor ESA National Occurrence Measures from UCMR 2 Screening Survey 

Data - Summary of System and Population Served Data - All Detections....................... 33

Exhibit 5-8: Acetochlor ESA National Occurrence Measures from UCMR 2 Screening Survey 

Data - Summary of System and Population Served Data - Detections > 1⁄2 HRL............. 34

Exhibit 5-9: Acetochlor ESA National Occurrence Measures from UCMR 2 Screening Survey 

Data - Summary of System and Population Served Data - Detections > HRL................. 35

Exhibit 5-10: Alachlor ESA National Occurrence Measures from UCMR 2 Screening Survey 

Data - Summary of System and Population Served Data - All Detections....................... 37

Exhibit 5-11: Alachlor ESA National Occurrence Measures from UCMR 2 Screening Survey 

Data - Summary of System and Population Served Data - Detections > 1⁄2 HRL............. 38

Exhibit 5-12: Alachlor ESA National Occurrence Measures from UCMR 2 Screening Survey 

Data - Summary of System and Population Served Data - Detections > HRL................. 39

Exhibit 5-13: Metolachlor National Occurrence Measures from UCMR 2 Screening Survey Data 

- Summary of System and Population Served Data - All Detections............................... 41

Exhibit 5-14: Metolachlor ESA National Occurrence Measures from UCMR 2 Screening Survey 

Data - Summary of System and Population Served Data - All Detections....................... 42
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

viii

Exhibit 5-15: Metolachlor OA National Occurrence Measures from UCMR 2 Screening Survey 

Data - Summary of System and Population Served Data - All Detections....................... 44

Exhibit 5-16: NDBA National Occurrence Measures from UCMR 2 Screening Survey Data -

Summary of System and Population Served Data - All Detections.................................. 45

Exhibit 5-17: NDBA National Occurrence Measures from UCMR 2 Screening Survey Data -

Summary of System and Population Served Data - Detections > 1⁄2 HRL ....................... 47

Exhibit 5-18: NDBA National Occurrence Measures from UCMR 2 Screening Survey Data -

Summary of System and Population Served Data - Detections > HRL ........................... 48

Exhibit 5-19: NDEA National Occurrence Measures from UCMR 2 Screening Survey Data -

Summary of System and Population Served Data - All Detections.................................. 49

Exhibit 5-20: NDEA National Occurrence Measures from UCMR 2 Screening Survey Data -

Summary of System and Population Served Data - Detections > 1⁄2 HRL ....................... 50

Exhibit 5-21: NDEA National Occurrence Measures from UCMR 2 Screening Survey Data -

Summary of System and Population Served Data - Detections > HRL ........................... 51

Exhibit 5-22: NDMA National Occurrence Measures from UCMR 2 Screening Survey Data -

Summary of System and Population Served Data - All Detections.................................. 53

Exhibit 5-23: NDMA National Occurrence Measures from UCMR 2 Screening Survey Data -

Summary of System and Population Served Data - Detections > 1⁄2 HRL ....................... 54

Exhibit 5-24: NDMA National Occurrence Measures from UCMR 2 Screening Survey Data -

Summary of System and Population Served Data - Detections > HRL ........................... 55

Exhibit 5-25: NMEA National Occurrence Measures from UCMR 2 Screening Survey Data -

Summary of System and Population Served Data - All Detections.................................. 57

Exhibit 5-26: NMEA National Occurrence Measures from UCMR 2 Screening Survey Data -

Summary of System and Population Served Data – Detections > 1⁄2 HRL....................... 58

Exhibit 5-27: NMEA National Occurrence Measures from UCMR 2 Screening Survey Data -

Summary of System and Population Served Data - Detections > HRL ........................... 59

Exhibit 5-28: NPYR National Occurrence Measures from UCMR 2 Screening Survey Data -

Summary of System and Population Served Data - All Detections.................................. 60

Exhibit 5-29: NPYR National Occurrence Measures from UCMR 2 Screening Survey Data -

Summary of System and Population Served Data - Detections > 1⁄2 HRL ....................... 62

Exhibit 5-30: NPYR National Occurrence Measures from UCMR 2 Screening Survey Data -

Summary of System and Population Served Data - Detections > HRL ........................... 63
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

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Acronyms

CAS RN Chemical Abstract Services Registry Number

CCL Candidate Contaminant List

CDX Central Data Exchange

CWS Community Water System

CWSS Community Water System Survey

DQO Data Quality Objective

DSMRT Distribution System Maximum Residence Time

EPTDS (or EP) Entry Point to the Distribution System

EPA Environmental Protection Agency

GW Ground Water

GUDI Ground Water Under Direct Influence (of Surface Water)

HRL Health Reference Level

MCL Maximum Contaminant Level

MRL Minimum Reporting Level (or Limit)

NCOD National Contaminant Occurrence Database

NPDWR National Primary Drinking Water Regulations

NTNCWS Non-Transient Non-Community Water System

OGWDW Office of Ground Water and Drinking Water

PWS Public Water System

PWSID Public Water System Identification Number

QA Quality Assurance

QC Quality Control

SDWA Safe Drinking Water Act

SDWARS Safe Drinking Water Accession and Review System

SDWIS/Fed Safe Drinking Water Information System / Federal Version

SW Surface Water

TNCWS Transient Non-Community Water System

UCM Unregulated Contaminant Monitoring

UCMR Unregulated Contaminant Monitoring Regulation

USEPA United States Environmental Protection Agency
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EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

1

1 Introduction

The United States Environmental Protection Agency (EPA) conducted drinking water 

monitoring under the agency’s second Unregulated Contaminant Monitoring Regulation 

(UCMR 2). UCMR 2 monitoring was conducted for selected unregulated contaminants in 

drinking water under the authority of Section 1445(a)(2) of the Safe Drinking Water Act 

(SDWA), as amended in 1996. Unregulated contaminants are contaminants for which there is no

established or proposed National Primary Drinking Water Regulation (NPDWR). The intent of 

this monitoring is to gather more scientific information on these unregulated contaminants to 

support EPA assessments of national occurrence in drinking water to determine whether 

additional drinking water regulations are needed.

This report presents EPA’s analysis of the national occurrence of unregulated 

contaminants that were monitored at PWSs under the UCMR 2. The report additionally provides 

an overview of the regulatory background for unregulated contaminant monitoring, the design 

and implementation of the UCMR 2 monitoring program, data management and quality 

assurance/quality control (QA/QC), and the occurrence measures used and any limitations of 

those measures.

The analyses presented in this report represent the final UCMR 2 data set, which includes 

analytical results of water samples from all 4,620 systems that were expected to submit UCMR 2

data (100% compliance). To accommodate final (late) UCMR 2 reporting, the data system 

remained open for submission of data through December 31, 2011. This document and the 

UCMR website (http://water.epa.gov/lawsregs/rulesregs/sdwa/ucmr/data.cfm) both present the 

final data set, which includes the sample data submitted through December 2011. This document 

also provides detailed descriptions of EPA’s management and analysis of the data.

To meet agency deadlines in the deliberative process for Regulatory Determination 3, 

data submitted through June 2011 were used and presented in the Federal Register notice, the 

Regulatory Determination 3 Support Document (USEPA, 2014a), and the Protocol for the 

Regulatory Determination 3 (USEPA, 2014b). For completeness, Appendix D presents the June 

2011 data snapshot. The June 2011 data are only slightly different from the final December 2011 

UCMR 2 data set described in this report. The additional data in the December 2011 data set

include:

• For the Assessment Monitoring contaminants, a few systems provided additional data to 

complete their UCMR requirements, and two additional systems (one from California, 

one from Region 9 tribes) provided results in the final data set. On average, the number 

of records for each contaminant increased by 137 samples (out of an average total of 

32,148 samples); a sample size increase of less than 0.5%. All new samples were nondetections.

• For the Screening Survey contaminants, no new systems provided monitoring results in 

the final data set; however, a few systems provided additional data to complete their 

UCMR requirements. On average, the number of records for each contaminant increased 

by 57 samples (out of an average total of 11,169 samples for the acetanilide parent and 
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

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degradate herbicides, representing an approximate 0.5% increase in sample size, and out 

of an average total of 18,101 samples for the nitrosamines, representing an approximate 

0.3% increase in sample size). With the exception of 20 new NDMA detections, all of the 

new samples were non-detections. NDMA occurrence increased from 10.2% of samples 

with detections in the June 2011 data set to 10.3% of samples with detections in the final 

UCMR 2 data set. There was no change in the number and percentage of PWSs with 

NDMA detections (27%).

1.1 Regulatory Background

SDWA, as amended in 1986, required PWSs to monitor for specified unregulated 

contaminants on a five-year cycle and to report the monitoring results to the states. Monitoring of 

unregulated drinking water contaminants was historically conducted under the Unregulated 

Contaminant Monitoring (UCM) program. Data from the first round of monitoring (UCM Round 

1) were collected from 1988 to 1992. All community water systems (CWSs) and non-transient 

non-community water systems (NTNCWSs) that had more than 150 service connections were 

required to conduct monitoring for select unregulated contaminants in drinking water. Smaller 

systems (those with 150 service connections or fewer) were not universally required to 

participate in the monitoring, but they were required to be available for monitoring if the state 

decided such monitoring was necessary. In 1993, Congress amended SDWA to add new 

contaminants for unregulated contaminant monitoring. Data from UCM Round 2 monitoring 

were collected from 1993 to 1997. 

The 1996 SDWA Amendments directed EPA to develop a revised program for the 

monitoring of unregulated contaminants and to, once every 5 years, identify no more than 30 

contaminants to be monitored. The first UCMR (UCMR 1), and related rules, replaced the older 

UCM requirements. The details of UCMR 1 were formally published in the Federal Register on 

September 17, 1999 (64 FR 50556; USEPA, 1999). The UCMR program was designed to 

provide a national assessment of the occurrence of select unregulated contaminants in PWSs. 

UCMR 1 provided for the selection of the contaminants to be monitored, the requirements for 

PWSs that must conduct monitoring (from 2001-2005), and establishment of the process to 

report all UCMR monitoring results to EPA. The second UCMR (UCMR 2; USEPA, 2007) 

established a somewhat revised monitoring program; this monitoring was primarily conducted 

between January 2008 and December 2010.

The 1996 amendments to SDWA instituted the Candidate Contaminant List (CCL) and 

the National Contaminant Occurrence Database (NCOD) in addition to the UCMR programs. 

Development of each successive UCMR is coordinated with the CCL and the NCOD to provide 

the information EPA needs to determine which drinking water contaminants have the greatest 

potential to present a meaningful opportunity to reduce health risk through an NPWDR. UCMR 

provides EPA with the data necessary to identify contaminants that may require regulation as 

part of the CCL (USEPA, 2002; USEPA) and to determine if a contaminant occurs at a 

frequency and level of public health concern to inform the RD3 process (USEPA, 2008a). The

UCMR, CCL and regulatory determinations are coordinated parts of EPA’s risk management 

process, and they support and inform each other. The data collected through the UCMR program 

are stored in the NCOD to facilitate review of contaminant occurrence in drinking water. These 
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

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data may guide the development of subsequent CCLs and ultimately support the EPA 

Administrator's regulatory determinations.

Data from UCMR 2 were used by EPA to evaluate the occurrence of contaminants on the 

third Contaminant Candidate List (CCL 3). Sixteen UCMR 2 contaminants are included on 

CCL 3: 1,3-dinitrobenzene, acetochlor, acetochlor ethane sulfonic acid (ESA), acetochlor 

oxanilic acid (OA), alachlor ESA, alachlor OA, dimethoate, metolachlor, metolachlor ESA, 

metolachlor OA, N-nitroso-diethylamine (NDEA), N-nitroso-dimethylamine (NDMA), 

N-nitroso-di-n-propylamine (NDPA), N-nitroso-pyrrolidine (NPYR), hexahydro-1,3,5-

trinitro-1,3,5-triazine (RDX), and terbufos sulfone. The nine UCMR 2 contaminants that are not 

on CCL 3 are: alachlor, 2,2',4,4',5,5'-hexabromodiphenyl ether (BDE-153), 

2,2',4,4',5-pentabromodiphenyl ether (BDE-99), 2,2',4,4',6-pentabromodiphenyl ether 

(BDE-100), 2,2',4,4'-tetrabromodiphenyl ether (BDE-47), 2,2',4,4',5,5'-hexabromobiphenyl 

(HBB), N-nitroso-di-n-butylamine (NDBA), N-nitroso-methylethylamine (NMEA), and 

2,4,6-trinitrotoluene (TNT). For more information about EPA’s Regulatory Determination 3, 

including occurrence analyses, see USEPA Protocol for the Regulatory Determination 3 (2014a). 

1.2 Two-Stage Analytical Approach

EPA developed a two-stage analytical approach to evaluate the UCMR 2 contaminant 

occurrence data. This two-stage analytical approach was previously developed (and peer

reviewed) for other EPA Office of Ground Water and Drinking Water (OGWDW) national 

occurrence studies, including the first Six-Year Review of National Primary Drinking Water 

Regulations (USEPA, 2003a), UCMR 1 (USEPA, 2008b), and previous rounds of the CCL and 

the regulatory determination process (USEPA, 2002; USEPA, 2008a). 

The first stage of analysis provides a straightforward evaluation of occurrence of all 

contaminants under consideration. This “Stage 1 analysis” of occurrence assesses the quality and 

characteristics of the data and then uses the data to conduct simple, conservative assessments for 

a broad evaluation of contaminant occurrence and population exposure.1 Occurrence for each 

UCMR 2 contaminant was assessed based on samples, systems, and population served by 

systems. A typical Stage 1 analysis is the actual count (or percentage) of systems with at least 

one analytical detection2 of a specific contaminant.

Based on the Stage 1 analysis, any contaminant found to have significant occurrence can 

be analyzed with a more rigorous “Stage 2 analysis.” The Stage 2 analysis is a parametric 

estimation based on calculation of mean contaminant concentrations at each system, and can 

provide occurrence estimates that help characterize contaminant occurrence at concentrations 

below the MRL. The Stage 2 occurrence analyses are less conservative than Stage 1 (since the 

Stage 2 analysis is based on estimated mean concentrations) and also provide occurrence 

 

1 These analyses are conservative in that they are protective of human health (i.e., they are more likely to 

overestimate risks to human health than underestimate them).

2 By definition, an analytical detection is a quantified concentration that is equal to or greater than the laboratory 

method minimum reporting level, the MRL.
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

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estimates that may be more reflective of the potential for chronic exposure. This report presents 

only Stage 1 analyses.

1.3 Analytical Tools

Database manipulation, data quality checks, and overall data management were 

conducted in Microsoft Access. The data analyses were also conducted with Microsoft Access. 

Upon completion, results of the analyses were exported into Microsoft Excel for development of 

report tables that present the occurrence findings. 
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

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2 UCMR 2 Program Overview

2.1 UCMR 2 Monitoring Design and Contaminant List

The UCMR program design includes a three-tiered approach for monitoring of 

contaminants based on the availability of analytical methods (and related laboratory capacity) 

and contaminant prioritization (with known and/or suspected health effects as the top priority). 

Assessment Monitoring (List 1) is the largest in scope of the three monitoring components (or 

tiers) and includes priority contaminants for which analytical methods and/or techniques are 

well-established. Screening Survey (List 2) monitoring primarily targets contaminants with 

analytical methods that were recently developed and techniques that are not yet widely used. PreScreen Testing (List 3) is for limited and targeted monitoring of contaminants for which 

analytical methods may utilize specialized testing equipment. 

Exhibit 2-1 presents the list of 10 Assessment Monitoring contaminants and 15 Screening 

Survey contaminants monitored under UCMR 2. The Assessment Monitoring contaminants fall 

into three main groups: insecticides and insecticide degradates, flame retardants, and explosives. 

The Screening Survey contaminants fall into two main groups: acetanilide herbicides with their 

degradation products, and nitrosamines. The Pre-Screen Testing provisions of the UCMR 

program were not implemented under UCMR 2.

Exhibit 2-1: Contaminants Monitored Under UCMR 2

Contaminant Name

Chemical 

Abstract 

Services 

Registry 

Number 

(CAS RN)

Minimum 

Reporting 

Level 

(MRL)

Analytical 

Method Contaminant Use and Description

ASSESSMENT MONITORING

Insecticide and Insecticide Degradate

Dimethoate 60-51-5 0.7 μg/L EPA 527

Insecticide used on cotton and other 

field crops, orchard crops, vegetable 

crops, in forestry, and residential uses.

Terbufos sulfone 56070-16-7 0.4 μg/L EPA 527

Parent compound (terbufos) used for 

systemic control of soil-borne insects 

and nematodes in fields of corn, grain 

sorghum, and sugar beets.
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

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Contaminant Name

Chemical 

Abstract 

Services 

Registry 

Number 

(CAS RN)

Minimum 

Reporting 

Level 

(MRL)

Analytical 

Method Contaminant Use and Description

Flame Retardants

2,2',4,4'-tetrabromodiphenyl 

ether (BDE-47) 5436-43-1 0.3 μg/L EPA 527

Flame retardants added to other 

materials (for products such as 

computer monitors, televisions, textiles, 

and plastic foams).

2,2',4,4',5-

pentabromodiphenyl ether 

(BDE-99)

60348-60-9 0.9 μg/L EPA 527

2,2',4,4',5,5'-

hexabromodiphenyl ether 

(BDE-153)

68631-49-2 0.8 μg/L EPA 527

2,2',4,4',6-

pentabromodiphenyl ether 

(BDE-100)

189084-64-8 0.5 μg/L EPA 527

2,2',4,4',5,5'-

hexabromobiphenyl (HBB) 59080-40-9 0.7 μg/L EPA 527

Flame retardant additive; production of 

PBBEs ended in 1976 in US after an 

incident of significant accidental 

agricultural contamination in 1973.

Explosives

2,4,6-trinitrotoluene (TNT) 118-96-7 0.8 μg/L EPA 529

Used as an explosive in bombs and 

grenades and as a propellant; small 

amounts used for industrial explosive 

applications, such as deep well and 

underwater blasting; chemical 

intermediate in manufacture of dyestuffs 

and photographic chemicals.

1,3-dinitrobenzene 99-65-0 0.8 μg/L EPA 529

Used in explosives; also formed as a 

by-product during the manufacture of 

the explosive trinitrotoluene (TNT); used 

in the manufacture of aramid fibers, 

spandex, and dyes.

Hexahydro-1,3,5-trinitro1,3,5-triazine (RDX) 121-82-4 1 μg/L EPA 529

Used in detonators, primers, mines, 

rocket boosters, and plastic explosives; 

also used in fireworks and demolition 

blocks, and as a rodenticide.

SCREENING SURVEY

Acetanilide Parent Herbicides and Acetanilide Herbicide Degradates

Acetochlor 34256-82-1 2 μg/L EPA 525.2

The active ingredient in a number of 

herbicides used on corn crops to control 

annual grasses and certain broadleaf 

weeds.

Alachlor 15972-60-8 2 μg/L EPA 525.2

Widely used herbicide; primarily used in 

the Midwest to control annual grasses 

and certain broadleaf weeds on crops 

such as corn, sorghum, and soybeans.

Metolachlor 51218-45-2 1 μg/L EPA 525.2

Broad spectrum herbicide used for 

general weed control in non-crop areas; 

widely used on crops such as corn, 

cotton, peanuts, grass for seed 

production, nurseries, hedgerows/ 

fencerows, and landscape plantings.
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

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Contaminant Name

Chemical 

Abstract 

Services 

Registry 

Number 

(CAS RN)

Minimum 

Reporting 

Level 

(MRL)

Analytical 

Method Contaminant Use and Description

Acetochlor ethane sulfonic 

acid (ESA) 187022-11-3 1 μg/L EPA 535

Degradation products of acetochlor. Acetochlor oxanilic acid 

(OA) 184992-44-4 2 μg/L EPA 535

Alachlor ethane sulfonic acid 

(ESA) 142363-53-9 1 μg/L EPA 535

Degradation products of alachlor.

Alachlor oxanilic acid (OA) 171262-17-2 2 μg/L EPA 535

Metolachlor ethane sulfonic 

acid (ESA) 171118-09-5 1 μg/L EPA 535

Degradation products of metolachlor. Metolachlor oxanilic acid 

(OA) 152019-73-3 2 μg/L EPA 535

Nitrosamines

N-nitroso-diethylamine 

(NDEA) 55-18-5 0.005 μg/L EPA 521 Nitrosamines can form as intermediates 

and byproducts in chemical synthesis 

and manufacture of rubber, leather, and 

plastics; can form spontaneously by 

reaction of precursor amines with

nitrosating agents (nitrate and related 

compounds), or by action of nitratereducing bacteria. Foods such as

bacon and malt beverages can contain 

nitrosamines; there also is evidence 

that they form in the upper 

gastrointestinal (GI) tract. Research 

suggests nitrosamines may also be 

produced as disinfection byproducts,

particularly as a result of chloramination 

of drinking water.

N-nitroso-dimethylamine 

(NDMA) 62-75-9 0.002 μg/L EPA 521

N-nitroso-di-n-butylamine 

(NDBA) 924-16-3 0.004 μg/L EPA 521

N-nitroso-di-n-propylamine 

(NDPA) 621-64-7 0.007 μg/L EPA 521

N-nitroso-methylethylamine 

(NMEA) 10595-95-6 0.003 μg/L EPA 521

N-nitroso-pyrrolidine (NPYR) 930-55-2 0.002 μg/L EPA 521

The final UCMR 2 rule maintains the basic program design of the original UCMR, 

building upon the structure established by the original rule for this cyclical program. The primary 

design changes between UCMR 1 and UCMR 2 include: (1) strengthening the Screening Survey 

statistical sample by increasing the number of systems monitoring; (2) revising and clarifying the 

list of required “data elements”; and, (3) specifying both entry point and distribution system 

monitoring for certain contaminants. Other minor revisions reflected “lessons learned” during 

UCMR 1. 

UCMR 2 monitoring requirements for PWSs varied according to system size. The three 

size categories under the program are “small” (serving 10,000 or fewer people), “large” (serving 

between 10,001 and 100,000 people) and “very large” (serving more than 100,000 people).

UCMR 2 required all large and very large CWSs and NTNCWSs, plus a statistically 

representative national sample of 800 small CWSs and NTNCWSs, to monitor for the 

Assessment Monitoring contaminants. The sample of 800 small systems represents the 

approximately 62,000 small systems operating nationally. Additionally, EPA required 
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

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monitoring of the 15 Screening Survey contaminants by all very large PWSs, 320 selected large 

PWSs, and 480 selected small PWSs. The Screening Survey sample of 800 small and large 

systems was designed to be representative of the approximately 65,000 small and large systems 

operating nationally. See Section 4.3.3 for more detail on national extrapolation of monitoring 

results based on the representative system sampling.

Both Assessment Monitoring and the Screening Survey had the same monitoring 

requirements for ground water (GW) and surface water (SW) systems. Surface water and ground 

water under direct influence (GUDI) of surface water systems were required to sample for four 

consecutive quarters (per entry point to the distribution system) over a 12-month period, with 

samples collected 3 months apart. Ground water systems had to sample only twice (per entry 

point), 5 to 7 months apart within a 12-month period. EPA, in coordination with the states,

assigned individual monitoring schedules (year and month of monitoring) to each PWS subject 

to UCMR 2. 

Two categories of PWSs were exempt from UCMR 2 monitoring. First, PWSs that 

purchase their entire water supply from another PWS were not included since monitoring at these 

systems could result in double-counting of estimated population exposure (i.e., the PWSs selling 

water are also monitoring and reporting their contaminant occurrence findings). Second, 

transient non-community water systems (TNCWSs) were excluded since estimating contaminant 

exposure for transient populations can be difficult and inconclusive. The exclusion of these two 

categories of PWSs from UCMR 2 monitoring is consistent with the exclusion of the same two 

categories of PWSs from most compliance monitoring requirements. Sections 2.2 and 2.3 

describe the PWSs that were required to conduct UCMR 2 monitoring. See Exhibit 2-2 for the 

full breakdown of each program component by system size and source water type. Note that the 

small and large systems were further subdivided into narrower categories for the purpose of 

constructing a stratified random sample. See Reference Guide for the Second Cycle of the 

Unregulated Contaminant Monitoring Regulation (UCMR 2) (USEPA, 2006) for additional 

information about implementation of UCMR 2.

2.2 Assessment Monitoring

EPA maintained the same basic statistical design used for UCMR1 for its UCMR 2

national representative sample of 800 small systems for Assessment Monitoring. The sample size 

was determined by a combination of statistical and budgetary considerations. A sample of 800 

systems is more than the approximately 720 systems (659 CWSs and 61 NTNCWSs) needed to 

meet programmatic data quality objectives (DQOs). It also enables the selection of at least two 

PWSs in each state to ensure a broad and diverse geographic coverage. The small system 

representative sample was designed to account for different system sizes, types of systems, 

sources of water supply, contaminants likely to be found, and geographic location (70 FR 49093; 

USEPA, 2005). The UCMR 1 design was subjected to peer review and improved by 

recommendations of the peer reviewers, as well as suggestions made during the public comment 

and response process in developing UCMR 1. The details of the UCMR 1 design are included in 

USEPA (2001). 

As with UCMR 1, UCMR 2 required that all large and very large CWSs and NTNCWSs 

that do not purchase all of their water from another system, monitor their water for the presence 

of the 10 Assessment Monitoring contaminants.
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A total of 4,140 systems (800 small, 2,942 large, and 398 very large) submitted 

Assessment Monitoring results. 

Assessment Monitoring samples were collected at the entry point(s) to the distribution 

system (EPTDSs) (for systems with multiple EPTDSs, samples were required to be collected 

from every entry point3

). PWSs were allowed to collect “raw source water” samples only in 

those instances where groundwater enters the distribution system untreated at the EPTDS, was a 

change from UCMR 1.

2.3 Screening Survey

In addition to UCMR 2 Assessment Monitoring, UCMR 2 required monitoring for 15 

Screening Survey contaminants. The UCMR 2 Screening Survey was designed to increase the 

statistical strength of the sampling results compared to the UCMR 1 Screening Survey design. 

This was accomplished in two ways. First, the UCMR 2 Screening Survey used a larger stratified 

random sample of approximately 800 systems, as compared to 300 under UCMR 1. The sample 

size was derived from the same rationale as that for Assessment Monitoring, but the sample 

frame was expanded to include large systems. Second, this Screening Survey included a census 

of very large PWSs. This approach minimizes the possibility of missing contaminant occurrence 

at the systems that serve the largest portion of the population while keeping the number of 

systems required to conduct the Screening Survey monitoring relatively small. No small systems 

were selected to participate in more than one component of UCMR 2 (i.e., if a small system was 

selected for Assessment Monitoring, it was excluded from possible selection for the Screening 

Survey). The sample of 800 systems serving 100,000 or fewer people was divided uniformly 

across 10 system size and water source strata (as was done for the prior Screening Survey under 

UCMR 1). For more detailed information on the selection of the Screening Survey PWSs, refer 

to the Unregulated Contaminant Monitoring Regulation (UCMR) for Public Water Systems 

Revisions; Proposed Rule (USEPA, 2005).

For UCMR 1, the Screening Survey sample size was limited to 300 systems (120 large 

and 180 small PWSs). Screening Survey data from UCMR 1 were generally expected to provide 

only enough information for EPA to determine whether a contaminant should be elevated to 

future Assessment Monitoring. The resulting data of all systems combined were designed to be 

used for national estimates. Individual system strata had variances that were too large to provide 

meaningful estimates. The increased sample size of the UCMR 2 Screening Survey enables 

national estimates for each of the system size strata. A total of 1,198 systems (480 small, 320 

large, and 398 very large) submitted Screening Survey results.

As for Assessment Monitoring, Screening Survey samples were also collected at the 

EPTDSs for all Screening Survey contaminants. However, for those systems that utilize chemical 

disinfection, additional samples were collected for nitrosamines at the distribution system 

maximum residence time (DSMRT) sampling point associated with each plant/water source.

 3 Ground water systems could limit monitoring to representative entry points if they had appropriate documentation 

and state approval.
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Exhibit 2-2: Number of PWSs that Monitored Under UCMR 2

Size 

Category Population served

Assessment Monitoring 

Systems

Screening Survey 

Systems

Total

GW SW + GUDI GW SW + GUDI

25 to 500 104 5 80 80 269

501 to 3,300 259 48 80 80 467

3,301 to 10,000 255 129 80 80 544

Small1 Systems serving 

25 to 10,000 people 618 182 240 240 1,280

10,001 to 50,000 1,239 1,246

752

(subset of the 

1,239)

852

(subset of the 

1,246)

2,485

50,001 to 100,000 135 322

762

(subset of the 

135)

842

(subset of the 

322)

457

Large1 Systems serving 10,001 to 100,000 

people

1,374 1,568

1512

(subset of 

the 1,374)

1692

(subset of the 

1,568)

2,942

Very 

Large

Systems serving 

over 100,000

people

63 335 63 335 398

Total UCMR 2 Systems 2,055 2,085 454 744 4,620

1 For the purpose of constructing stratified random samples, the small PWSs were grouped into three subcategories

and the large PWSs were grouped into two subcategories.

2 The number of systems included in these cells are excluded from row totals (as they are a subset of the systems 

conducting Assessment Monitoring), but are included in the column totals to show the overall total number of systems 

conducting Screening Survey monitoring. 
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3 UCMR 2 Data Description

This section of the report describes the process of submitting, managing, and quality 

checking the UCMR 2 occurrence data. It also describes the assessment of the representativeness 

and completeness of the data set as well as various temporal, geographical, and other 

characteristics of the data. 

The analyses presented in this report represent the final UCMR 2 data set, which includes 

analytical results of water samples from all 4,620 systems that were expected to submit UCMR 2

data (100% compliance). To accommodate final (late) UCMR 2 reporting, the data system 

remained open for submission of data through December 31, 2011. This document and the 

UCMR website (http://water.epa.gov/lawsregs/rulesregs/sdwa/ucmr/data.cfm) both present the 

final data set, which includes the sample data submitted through December 2011. This document 

also provides detailed descriptions of EPA’s management and analysis of the data.

To meet Agency deadlines in the deliberative process for the Preliminary Regulatory 

Determination 3, data submitted through June 2011 were used as the basis for occurrence 

analyses under that effort. The results of those analyses are presented in the Federal Register

notice, the Regulatory Determination 3 Support Document (USEPA, 2012a), and the Protocol 

for the Regulatory Determination 3 (USEPA, 2014b). For completeness, Appendix D of this 

document presents the June 2011 data snapshot. The June 2011 data are only slightly different 

from the final December 2011 UCMR 2 data set described in this report. The additional data in 

the December 2011 data set include:

• For the Assessment Monitoring contaminants, a few systems provided additional data to 

complete their UCMR requirements, and two additional systems (one from California, 

and one from Region 9 tribes) provided results in the final data set. On average, the 

number of records for each contaminant increased by 137 samples (out of an average 

total of 32,148 samples); a sample size increase of less than 0.5%. All new samples were 

non-detections.

• For the Screening Survey contaminants, no new systems provided monitoring results in 

the final data set; however, a few systems provided additional data to complete their 

UCMR requirements. On average, the number of records for each contaminant increased 

by 57 samples (out of an average total of 11,169 samples for the acetanilide parent and 

degradate herbicides, representing an approximate 0.5% increase in sample size, and out 

of an average total of 18,101 samples for the nitrosamines, representing an approximate 

0.3% increase in sample size). With the exception of 20 new NDMA detections, all of the 

new samples were non-detections. NDMA occurrence increased from 10.2% of samples 

with detections in the June 2011 data set to 10.3% of samples with detections in the final 

UCMR 2 data set. There was no change in the number and percentage of PWSs with 

NDMA detections (27%).
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3.1 Data Submittal Process

This section describes the process by which the UCMR 2 data were submitted by PWSs

and laboratories. 

Laboratories conducting UCMR sample analysis were also responsible for posting the 

sample analytical data to the Safe Drinking Water Accession and Review System (SDWARS). 

Access to SDWARS, which is the main database for upload, review, and storage of UCMR 2

data, is through the Central Data Exchange (CDX), EPA’s electronic reporting system. The CDX 

is the point of entry on the Environmental Information Exchange Network where PWSs, 

laboratories, states, and EPA submit, view, review, and (in the case of UCMR large systems) 

approve UCMR 2 occurrence data. Numerous security controls have been established to prevent 

unauthorized entry into the CDX and the SDWARS/UCMR storage system, and to prevent the 

potential loss of data or inappropriate transformations. CDX required users to register prior to 

being allowed access to data reporting and reviewing sections (only records from registered 

laboratories and systems could be uploaded into the database). In addition, the SDWARS/UCMR 

system has a number of electronic back-up provisions to minimize the risk of data being lost 

through tampering, system failure, or inadvertent deletion. 

For the large systems, data were posted directly to SDWARS by laboratories. PWSs 

accessed SDWARS to review the data and approve its release to EPA. Large PWSs had 60 days 

to review the data posted by their laboratories. After 60 days, if a PWS had not reviewed its 

UCMR 2 data, it was automatically approved and released to EPA (and concurrently to the state) 

as the system’s official UCMR 2 results. 

EPA collected and reviewed occurrence data for small systems. EPA performed a 

thorough QC review of the data for small systems as part of the agency’s oversight of the 

contract laboratories performing sample collection and analyses. Small PWSs were authorized to 

review their data in SDWARS, but were not responsible for final data approval. The QC review 

was provided to states for review and comment.

For all system sizes, when the EPA QC review was complete and the system’s 60-day 

review period had passed, the data were considered valid. Data that passed final quality 

assessments were made available to the public through the National Contaminant Occurrence 

Database (NCOD), which is accessible through the EPA website. 

3.2 Data Management and Quality Assurance

This section describes how the UCMR 2 data were collected, maintained, and organized 

by EPA. QA/QC procedures are also described. Data discussed in this section include the water 

sample analytical data (monitoring results that define contaminant occurrence) and PWS 

inventory information (data that define characteristics of the participating PWSs). Exhibit 3-1

defines the data elements that were required to be provided with UCMR 2 sample results. 
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

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Exhibit 3-1: UCMR 2 Required Data Elements

Data Element Definition

Public Water 

System 

Identification 

(PWSID) Code

The code used to identify each PWS. The code begins with the standard 2-character postal 

state abbreviation or Region code; the remaining 7 numbers are unique to each PWS in the 

state. The same identification code must be used to represent the PWS identification for all 

current and future UCMR monitoring.

Public Water 

System Facility 

Identification Code

An identification code established by the state or, at the state’s discretion, by the PWS, 

following the format of a 5-digit number unique within each PWS for each applicable facility 

(i.e., for each source of water, treatment plant, distribution system, or any other facility 

associated with water treatment or delivery). The same identification code must be used to 

represent the facility for all current and future UCMR monitoring.

Water Source Type The type of source water that supplies a water system and sampling location. Systems must 

report one of the following codes for each sampling location:

SW Surface water (to be reported for water facilities that are served all or in part by a surface 

water source at any time during the 12-month period).

GW Ground water (to be reported for water facilities that are served entirely by a ground water 

source).

GU

Ground water under the direct influence of surface water (to be reported for water facilities 

that are served all or in part by ground water under the direct influence of surface water at 

any time during the 12-month sampling period), and are not served at all by surface water 

during this period.

MX Any combination of the three water types listed above.

Sampling Point 

Identification Code

An identification code established by the state, or at the state’s discretion, by the PWS, that 

uniquely identifies each sampling point. Each sampling code must be unique within each 

applicable facility, for each applicable sampling location (i.e., entry point to the distribution 

system or distribution system sample at maximum residence time). The same identification 

code must be used to represent the sampling location for all current and future UCMR 

monitoring.

Sampling Point 

Type Code A code that corresponds to the location of the sampling point.

EP Entry point to the distribution system.

MR Distribution system sample at maximum residence time.

Disinfectant 

Residual Type

The type of disinfectant in use at the time of UCMR sampling to maintain a residual in the 

distribution system for each Screening Survey sampling point. To be reported by systems 

required to conduct Screening Survey monitoring. Systems must report using the following 

codes for each Screening Survey sampling location (i.e., EP, MR):

CL Chlorine.

CA Chloramine.

OT All other types of disinfectant (e.g., chlorine dioxide).

ND No disinfectant used.

Sample Collection 

Date

The date the sample is collected, reported as 2-digit month, 2-digit day, and 4-digit year (i.e., 

01152008).

Sample 

Identification Code

An alphanumeric value up to 30 characters assigned by the laboratory to uniquely identify 

containers, or groups of containers, containing water samples collected at the same 

sampling location for the same sampling date.

Contaminant The unregulated contaminant for which the sample is being analyzed.

Analytical Method 

Code The identification code of the analytical method used.

Sample Analysis 

Type

The type of sample collected and/or prepared, as well as the fortification level. Permitted 

values include:

FS Field sample; sample collected and submitted for analysis under this rule.

LFSM Laboratory fortified sample matrix; a UCMR field sample with a known amount of the 

contaminant of interest added.
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

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Data Element Definition

LFSMD Laboratory fortified sample matrix duplicate; duplicate of the laboratory fortified sample 

matrix.

CF Concentration fortified; reported with sample analysis types LFSM and LFSMD, the 

concentration of a known contaminant added to a field sample.

Analytical Result—

Sign

A value indicating whether the sample analysis result was: (<) “less than” means the 

contaminant was not detected, or was detected at a level below the Minimum Reporting 

Level. (=) “equal to” means the contaminant was detected at the level reported in “Analytical 

Result—Value.”

Analytical Result—

Value

The actual numeric value of the analytical results for: field samples; laboratory fortified 

matrix samples; laboratory fortified sample matrix duplicates; and concentration fortified.

Laboratory 

Identification Code

The code, assigned by EPA, used to identify each laboratory. The code begins with the 

standard two-character state postal abbreviation; the remaining five numbers are unique to 

each laboratory in the state.

Sample Event Code

A code assigned by the PWS for each sample event. This will associate samples with the 

PWS monitoring plan to allow EPA to track compliance and completeness. Systems must 

assign the following codes:

SE1 Represents samples collected to meet the UCMR monitoring requirement for the first 

sampling period (all source types).

SE2 Represents samples collected to meet the UCMR monitoring requirement for the second 

sampling period (all source types).

SE3 Represents samples collected to meet the UCMR monitoring requirement for the third 

sampling period (SW and GU sources only).

SE4 Represents samples collected to meet the UCMR monitoring requirement for the fourth 

sampling period (SW and GU sources only).

UCMR 2 data that were ready for EPA review were extracted on a monthly basis from 

SDWARS via the CDX. EPA reviewed all UCMR 2 data that had already passed the laboratory 

and PWS reviews. In addition, the SDWARS database was developed with several automated 

data quality criteria checks designed into the database structure so only data that passed QA 

measures could be successfully imported into the database. The database conducts an automated 

data review and flags questionable records. Reasons for flagging records include, but are not 

limited to, missing required fields, or records that are duplicates (i.e., having the same PWSID, 

PWS Facility ID, Sampling Point ID, contaminant, and sample collection date).4 In addition, the 

database includes a “range check” that identifies data outliers or possible unit problems. For 

example, any reported contaminant concentration values that are a thousand-fold lower than 

most other low contaminant concentration values would be flagged and investigated, since such 

significantly lower results likely reflect an analytical unit conversion problem (mg/L versus 

μg/L) in the original raw data. 

For more details on the data quality review applied to the small system data, refer to the 

Standard Operating Procedure: NCOD Data Import for Small Systems for the Second Cycle of 

the Unregulated Contaminant Monitoring Regulation. Revision 1.0 (USEPA, 2009). For more 

details on the data quality review of the large system occurrence data, refer to the Quality 

 

4 Note that some duplicate records are legitimate and are retained in the data set. If a system sampled and got a high 

detection of a contaminant, and then re-sampled, both results are retained in the database. At the time of data 

analysis, the largest detection value would be used for all occurrence analyses.
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

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Assurance Project Plan for the Implementation of the Unregulated Contaminant Monitoring 

Regulation (USEPA, 2003b). 

3.3 Assessments of Data Representativeness and Completeness

To ensure that the UCMR 2 data and occurrence estimates dependably reflect national 

conditions, the representativeness and completeness of the UCMR 2 contaminant sample data 

were assessed. This section describes how the UCMR 2 data were assessed for 

representativeness and completeness.

3.3.1 Data Representativeness

Assessment Monitoring - Small Systems (Serving ≤ 10,000 Persons)

The UCMR 2 small system sampling design incorporated a stratified sampling approach 

to enable statistically valid national occurrence analyses according to system size (based on 

population served) and water source type (e.g. surface water, ground water).5 This stratified, 

population-weighted, random selection process is the same process used for UCMR 1 and is 

described in detail in the Statistical Design and Sample Selection for the Unregulated 

Contaminant Monitoring Regulation (USEPA, 2001). Statistical design and program DQOs, as 

well as cost and scheduling considerations resulted in a sample design that selected 800 small 

PWSs that collectively provide nationally representative contaminant occurrence data. 

EPA identified DQOs for the representative sample of small systems to include the 

following: data should provide unbiased national exposure estimates; and margins of error must 

be kept to ±1% with 99% confidence for CWSs and ±2.5% with 95% confidence for NTNCWSs. 

If the estimated percentage of PWSs with a detection is 1%, EPA must be able to state with 99% 

confidence that the true exposure fraction is between 0% and 2%. In other words, if the sampling 

plan were to be repeated many times, the true occurrence and exposure values would fall within 

the 1% margin of error around the estimate in 99% of all cases. 

Meeting the representativeness objective required that the designated sample of small 

systems conducting monitoring be stratified and implemented correctly. In a small number of 

cases, the originally selected small systems could not participate (due to closing, change in 

status, etc.). Replacement systems were statistically selected in the event that the original (or first 

or second replacement) system could not participate. 

Assessment Monitoring - Large and Very Large Systems (Serving > 10,000 Persons)

A census, such as that required for all eligible large systems under UCMR 2 Assessment 

Monitoring, is by definition the most representative type of sample design. All PWSs serving 

more than 10,000 people that submitted Assessment Monitoring UCMR 2 data. 

 5 The number of NTNCWSs designated and selected for monitoring does not support a statistically valid analysis of 

only NTNCWSs.
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Screening Survey - Small and Large Systems (Serving ≤ 100,000 Persons)

Screening Survey systems were selected from all large and small system subcategories,

with each of the five subcategories given equal importance.6 Therefore, 160 systems were 

selected from each size subcategory. Within each subcategory, selected systems were distributed 

evenly between surface water and ground water systems wherever possible. 

Screening Survey - Very Large Systems (Serving > 10,000 Persons)

All PWSs serving more than 100,000 people (approximately 400 systems) were required 

to conduct Screening Survey monitoring. 

3.3.2 Completeness

The DQO for completeness of the occurrence data has two components: that 90% of data 

submitted are acceptable (i.e., conform to QC criteria with all data elements present and 

accurate), and that acceptable data are obtained from 82.375% of selected PWSs. Although, as 

designed, all selected PWSs (i.e., 100%) are required to collect and report UCMR 2 occurrence

data, in practice some samples may not be collected and some results may not be reported. This 

DQO provides for adequate data quality for end-use applications while recognizing the practical 

realities of PWS monitoring that some required data are not generated and/or reported. The DQO 

to obtain acceptable data from 82.375% of PWSs is based on a calculation of the minimum 

requirements to produce nationally representative estimates of PWS contaminant occurrence 

with a 99% confidence interval and a 1% margin of error.

All (100%) of the 4,620 small, large, and very large PWSs required to participate in 

UCMR 2 collected and reported UCMR 2 occurrence data, surpassing the DQO goal of 

82.375%. Furthermore, as described earlier, the SDWARS database contained several data 

quality criteria checks, so only data that passed QA measures were successfully imported into the 

database. Thus, the DQO of 90% for acceptable data was also surpassed.

3.4 Additional Data Management Considerations

Additional QA/QC measures were applied to the UCMR 2 data set to evaluate other 

quality aspects of the occurrence data and system inventory data. The following section 

addresses data management steps taken with the UCMR 2 systems’ population-served values as 

they relate to consecutive systems, seller/purchaser relations, and the resulting potential doublecounting of populations served by systems. 

 6 Unlike Assessment Monitoring, system selection for the Screening Survey was not proportionately weighted by 

population served or by the proportion of systems in each size category. If the sample was weighted by population

served, a disproportionate number of large systems would be included in the Screening Surveys. If the sample were 

weighted by the number of systems in each size category, a disproportionate number of small systems would be 

represented.
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3.4.1 Population Adjustments

As described in Section 2.1, all “purchased systems” (systems purchasing 100% of their 

water from other systems) were exempt from UCMR 2 monitoring. However, exclusion of these 

systems meant the populations served by those systems would also be excluded from the 

exposure estimates conducted for the UCMR 2 analyses. Therefore, the populations served by 

the purchased systems were assigned to the systems they purchased from (the “wholesale 

systems”). To do this, EPA compiled a list of all purchased systems that sell water directly to the 

consumer. EPA then identified the wholesale system(s) from which each system on the list

purchases water. If a purchased system purchased 100% of its water from a single wholesale 

system, the population served by each purchased system was assigned to the wholesale system 

and added to wholesale system’s total population served. The contaminant occurrence measures 

that include these wholesale systems with their “adjusted” population-served values include the 

population served by the purchased systems. 

A total of 386 purchased systems purchase water from more than one seller. To avoid 

double-counting in these cases, the population served by the purchasing systems was assigned 

fractionally to its wholesalers. Since no data were available on the relative quantities of water 

purchased from the different wholesalers, a uniform distribution was assumed. To illustrate this 

simple uniform distribution, consider a single large system serving a population of 60,300 that 

purchases 100% of its water from three different systems. The compliance occurrence data from 

that purchasing system is excluded from the occurrence analyses because it is a purchased 

system; however, one-third of its population served (60,300 ÷ 3 = 20,100) is assigned to each of 

the three systems from which it purchases water. This way, the population served by purchased 

systems is included in the analyses and considerations for UCMR 2. 

3.4.2 Temporal Information

The UCMR 2 program was designed with concerns about temporal variability in mind. 

The study design addressed temporal variability in contaminant occurrence by defining a 

vulnerable period (i.e., the season of greatest likelihood of contaminant occurrence; generally the 

months of late spring and early summer, which are characterized by high volumes of surface 

water runoff and ground water recharge). At least one UCMR 2 sample at each applicable 

sampling point were required to be collected during that period. Each system was required to 

monitor for one year (12 consecutive months) during the three years of UCMR 2 monitoring

(2008 – 2010). For small systems, approximately one-third were scheduled to conduct 

monitoring in each of the three years; with UCMR 2 schedules staggered to ensure that results 

were collected from every month in every part of the country. Large systems could conduct their 

12 consecutive months of monitoring anytime during the UCMR 2 period. Like small systems, 

their monitoring schedules were spread throughout the year and included one monitoring period

during their most vulnerable season. By staggering system monitoring schedules and requiring 

monitoring during at least one vulnerable period, EPA ensured that the UCMR 2 results reflected

multiple seasons and multiple years of climatic conditions throughout the country and were not 

directly affected (or biased) by weather conditions of a single season, year, or geographic region. 
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

18

4 Description of Stage 1 Analytical Method

The Stage 1 analysis consists of simple, non-parametric measures of occurrence using the 

UCMR 2 data. Based on the occurrence findings of the Stage 1 analyses, among other 

considerations, more statistically rigorous parametric analyses for select contaminants can be 

conducted. These parametric occurrence analyses are referred to as Stage 2 analyses. This twostage analytical approach has been peer reviewed and used to conduct other occurrence analyses 

that supported Regulatory Determination 1 and 2 (USEPA, 2002; USEPA, 2008a) and Six-Year

Review (USEPA, 2003a). This section is a discussion of the Stage 1 analyses. Stage 2 analysis is 

briefly described in Section 1 of this document. 

4.1 Stage 1 Analysis

The basic Stage 1 analytical methodology is a conservative approach: occurrence 

measures are based on actual counts of whether a PWS has at least one sample analytical result

greater than a specified concentration threshold. This is roughly analogous to a measure based 

conservatively on peak contaminant occurrence (i.e., when a system’s occurrence is represented 

by the maximum concentration even if numerous other samples collected by the system were 

non-detections or had lower concentrations). The Stage 1 statistical analysis of the UCMR 2 data 

consists of direct counts and descriptive statistics of analytical sample data for each of the 

monitored contaminants. The analytical sample data define the presence or absence of a 

contaminant relative to the analytical method minimum reporting level (MRL) and, if present, 

the concentration of the detected contaminant.

These analyses were conducted to characterize occurrence by samples, systems, and 

populations served by systems. At the sample level, occurrence measures included: the number 

and percent of samples for each contaminant with analytical detections; and the minimum, 

median, maximum, 90th and 99th percentile concentration values of those detections. Systemlevel occurrence measures include the number and percent of systems with one or more 

analytical detections by contaminant. At the level of populations served, occurrence measures 

include the number and percent of customers served by systems with one or more analytical 

detections by contaminant.

All occurrence analyses presented in this report were stratified by water system source 

water type. The stratification by source water type was consistent with source water type

classification protocols used for past efforts (i.e., systems using GUDI and those using a mix of 

ground water and surface/GUDI sources were classified as surface water systems). 

The Stage 1 approach incorporates another conservative assumption: if a detection occurs 

in a single entry point in a system, then the entire population served by the system is exposed to 

the detected contaminant (i.e., even if there are other entry points with no detections that might 

dilute the concentration found in the single entry point sample). For example, if a PWS serves a 

population of 10,000 and finds a detection of a UCMR 2 contaminant in one of its two entry 

points on one occasion, the Stage 1 analytical methodology would estimate that the entire 

population served by the system (i.e., all 10,000 persons) was exposed to the maximum detected 

levels of the contaminant. 
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

19

In reality, many systems get water from multiple water sources (a mix of multiple wells, 

or more than one surface water source, or a combination of ground water and surface water

sources). In systems with multiple water sources or water intakes, contaminant occurrence in one 

source or entry point does not necessarily mean occurrence in all sources or entry points that 

distribute water to consumers. 

Entry point-level occurrence measures are also part of the Stage 1 analyses. EPA did not 

perform entry point-level analyses on any of the contaminants evaluated in this report. 

4.2 Threshold Evaluations

EPA performed occurrence evaluations of UCMR 2 contaminants relative to multiple 

concentration thresholds. One occurrence analysis was conducted relative to the MRL for each 

UCMR 2 contaminant. In this analysis, any concentration equal to or greater than the MRL was 

considered an analytical detection. Evaluations of occurrence relative to the MRL provide a 

baseline measure of occurrence.

Detections of UCMR 2 contaminants were also evaluated relative to two other 

concentration thresholds: the Health Reference Level (HRL) and one-half the HRL (1⁄2 HRL). 

The HRL is an EPA-defined risk-derived concentration for evaluating contaminant occurrence 

based on health effects information.7 There are two general approaches to the derivation of an 

HRL. One approach is used for chemicals that cause cancer and exhibit a linear response to dose,

and the other applies to non-carcinogens and carcinogens evaluated using a non-linear approach. 

See Appendix B of the “Protocol for the Regulatory Determination 3” USEPA (2012c) for 

detailed discussion of HRLs, including descriptions of the linear and non-linear approaches to 

HRL derivation. Conducting occurrence assessments relative to the health-based thresholds in 

addition to the MRL gives additional information on the degree as well as the frequency of 

contaminant occurrence and helps to better characterize the distribution of occurrence. 

Exhibit 4-1: Minimum Reporting Levels (MRLs) and Health Reference Levels 

(HRLs) for UCMR 2 Contaminants

Contaminant MRL

(μg/L)

HRL1

(μg/L)

Assessment Monitoring Contaminants

BDE-47 0.3 --

BDE-99 0.9 --

BDE-100 0.5 --

BDE-153 0.8 --

Dimethoate 0.7 15.4

1,3-Dinitrobenzene 0.8 0.7

 7 EPA evaluates the best available, peer-reviewed assessments and studies to characterize the human health effects 

that may result from exposure to individual contaminants when found in drinking water. Based on this 

characterization, the agency estimates an HRL for each contaminant. HRLs are not final determinations of the level 

of a contaminant in drinking water that is necessary to protect any particular population and are derived prior to the 

development of a complete exposure assessment.
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

20

Contaminant MRL

(μg/L)

HRL1

(μg/L)

HBB 0.7 --

RDX 1 21

Terbufos sulfone 0.4 0.35

TNT 0.8 --

Screening Survey Contaminants

Acetochlor 2 1

Acetochlor ESA 1 1

Acetochlor OA 2 1

Alachlor 2 22

Alachlor ESA 1 0.4

Alachlor OA 2 0.4

Metolachlor 1 700

Metolachlor ESA 1 700

Metolachlor OA 2 700

NDBA 0.004 0.033

NDEA 0.005 0.0004

NDMA 0.002 0.0006

NDPA 0.007 0.007

NMEA 0.003 0.0033

NPYR 0.002 0.002 1 Note: "--" indicates that there is no HRL for this contaminant. These 

UCMR 2 contaminants are not on CCL 3. 2 Alachlor is a regulated drinking water contaminant with a Maximum 

Contaminant Level (MCL) of 2 μg/L.

3 NDBA and NMEA are not on CCL 3; however, they do have HRLs,

since they are being evaluated by EPA alongside the other 

nitrosamines, as part of a nitrosamine group.

4.3 Additional Considerations for Stage 1 Analysis

4.3.1 Ground Water and Surface Water Comparisons

Given the different sampling schedules of ground water systems (two samples per year) 

and surface water systems (four samples per year), care must be taken regarding any samplelevel comparative analyses between the two source water types. For example, if the true rate of 

detection for a given contaminant were identical for both ground water and surface water

systems, one would expect to see roughly twice the number of detections in the surface water

systems simply because surface water systems collect twice as many samples. Estimating the 

percentage of detections by source water type (i.e., dividing the number of detections by number 

of samples taken for a particular source type) corrects for this difference and provides a fair 

comparison of detection rates across surface water and ground water systems. System-level and 

population-served-level analyses also account for the different sampling frequencies.

4.3.2 Large System and Small System Totals
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

21

When presenting the Stage 1 Analyses, it is sometimes useful to summarize the 

occurrence of a contaminant as a single number or percentage. When doing so for the 

Assessment Monitoring contaminants, however, consideration should be given to the distinction 

between analytical results from the small system sample and large system census. Simply adding 

the number of both small and large systems’ detections may undercount the actual number of 

detections at the nation’s small systems because of the differences in UCMR 2 monitoring for 

small and large systems (see Section 2.1). While such simple summaries accurately present the 

UCMR 2 monitoring results themselves, reasonable estimates of national contaminant 

occurrence require national extrapolation of the small system Assessment Monitoring occurrence 

data. These same considerations are applicable for the Screening Survey contaminants when 

summarizing occurrence as a single number or percentage using analytical results from the 

sample of small and large systems and the census of very large systems. 

4.3.3 Extrapolation of the Results

Under UCMR 2 Assessment Monitoring, the 800 small systems (serving 10,000 or fewer 

people) selected to conduct monitoring were a stratified, random, statistically-weighted sample 

of the nation’s small systems. These 800 small systems were chosen to represent the distribution 

of small system characteristics found at the national level. Consequently, contaminant 

occurrence findings for those 800 UCMR 2 small systems are representative of occurrence at the 

approximately 62,000 small systems operating nationally.8 Moreover, the 2.7 million persons 

served by the 800 UCMR 2 sampled systems are representative of the approximately 47 million 

served by all small systems nationally.

For the UCMR 2 Screening Survey, monitoring was required by 320 large PWSs serving 

10,001-100,000 people, and 480 small PWSs serving 10,000 or fewer people. These 800 small 

and large systems were chosen to represent the distribution of small and large system 

characteristics found at the national level. Thus, Screening Survey occurrence findings UCMR 2

are representative of occurrence at the approximately 65,000 small and large systems operating 

nationally, and the approximately 130 million served by those small and large systems.

To calculate national extrapolations, the percent of systems (or of populations served by 

systems) estimated to exceed a specified threshold is multiplied by the total number of systems 

(or population served) in the nation (see Exhibit 4-2). Estimates of national system and 

population-served numbers were developed from a combination of EPA’s Safe Drinking Water 

Information System (SDWIS), the Community Water System Survey (CWSS), and the UCMR. 

Analogous national extrapolations can also be made for the occurrence results of the Screening 

Survey small and large systems. However, for the Screening Survey, only aggregated national 

estimates are appropriate because the error margin may be too large in small subcategories (e.g., 

surface water or groundwater systems in a given size category) to be conclusive, particularly in 

cases where no detections occur. Monitoring results are carefully analyzed to assess the possible 

implications of results. 

 8 This national estimate of systems and population served by systems was developed from EPA’s Safe Drinking 

Water Information System (SDWIS), the Community Water System Survey (CWSS), and UCMR.
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

22

Exhibit 4-2 presents results from NDMA to illustrate how system-level estimates of 

national contaminant occurrence are calculated by extrapolation of UCMR 2 Screening Survey 

monitoring results for small and large systems. To estimate the national number of small ground 

water systems that are expected to have detections, the percentage of systems of that source 

water type/system size strata with detections of the contaminant (in this example, approximately 

4.17%) is multiplied by the estimated total number of small ground water systems in the nation

(57,818 systems). The result is an estimate of 2,409 small ground water systems that are 

expected to have detectable concentrations of the contaminant (assuming monitoring protocols 

similar to that used under UCMR 2). Note that the calculations used to produce the national 

estimates involve more significant digits than are shown in the table. Thus, due to rounding, 

some calculations (including the one above) may appear to be incorrect. Comparable calculations 

are used to estimate the population served nationally by systems in that source water type/system 

size category, and to make the corresponding extrapolations in the other source water 

type/system size categories. The national estimates for “All Small Systems” and “All Large 

Systems” were calculated by summing extrapolated ground water and surface water results in 

each category.

Exhibit 4-2: Example Calculation of National Estimates (Extrapolations) for 

UCMR 2 Small and Large Systems (serving ≤ 100,000 people) for 

Screening Survey Contaminants

Water Type National Inventory 1 Percentage ≥ MRL

(based on UCMR 2) National Estimate

Systems Population Systems Population Systems Population

Small Systems (serving ≤ 10,000 people)

Ground Water 57,818 37,685,557 4.17% 4.75% 2,409 1,790,869

Surface Water 3,866 8,928,745 30.83% 39.25% 1,192 3,504,746

All Small Systems 61,684 46,614,302 17.50% 23.60% 3,601 5,295,615

Large Systems (serving 10,001 - 100,000 people)

Ground Water 1,506 38,870,272 8.61% 11.23% 130 4,363,960

Surface Water 1,366 44,536,172 34.32% 37.51% 469 16,707,724

All Large Systems 2,872 83,406,444 22.19% 25.18% 598 21,071,684

1 National inventory data for systems and populations were developed from EPA’s SDWIS, the CWSS, and UCMR.

4.3.4 Stage 1 Analyses and the Statistically-Weighted Sample of Small Systems

The Stage 1 occurrence analysis consists of simple, non-parametric, descriptive statistics 

based directly upon the contaminant occurrence data. The 800 small systems required to conduct 

UCMR 2 Assessment Monitoring were selected as a statistically-weighted (primarily populationweighted) stratified sample, in a similar fashion that 800 small systems were selected for 

UCMR 1 monitoring. Because of the difficulties in calculating the statistical weighting 

parameters, the UCMR 1 occurrence findings did not incorporate adjustments for the 

statistically-weighted sample selection of the UCMR 1 small systems. However, a sensitivity 

analysis was conducted on the 800 UCMR 1 small systems to address the issue of adjusting the 

occurrence findings to account for the statistically-weighted sample of small systems. At every 

single detection level, the analysis found no significant statistical difference between estimates of 
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

23

the weighted and unweighted means (USEPA, 2008b). Since the 800 UCMR 2 small systems 

were selected in a similar fashion, it is expected that there would be no significant statistical 

difference between estimates of the weighted and unweighted means for UCMR 2 as well.
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

24

5 Stage 1 Occurrence Estimates

This section presents summary Stage 1 occurrence findings for the 25 contaminants 

monitored under UCMR 2. The following exhibits, evaluated together with the other analytical 

results included within this report and report appendices, provide a multi-faceted presentation of 

the frequency, degree, and distribution of the occurrence of those contaminants as sampled and 

reported under UCMR 2.

Basic occurrence information for all 25 UCMR 2 contaminants is summarized in Exhibit 

5-1 and Exhibit 5-2. Exhibit 5-1 shows sample-level results, including minimum, median, and 

maximum concentrations. Exhibit 5-2 shows system-level results, including data on populations 

served by systems with detections. Separate contaminant-specific sections and exhibits follow 

which provide more details on the occurrence results. These more detailed occurrence results are 

included only for contaminants with at least one detection. 

In the final UCMR 2 data set, 13 of the 25 contaminants were not detected in any of the 

large or small systems that sampled under UCMR 2. Eight of the 13 contaminants with no 

detections were from the Assessment Monitoring component: BDE-47, BDE-99, DBE-100, 

DBE-153, dimethoate, 1,3-dinitrobenzene, HBB, and TNT. The remaining five contaminants 

with no detections were from the Screening Survey component: acetochlor, acetochlor OA, 

alachlor, alachlor OA, and NDPA. One of the 25 contaminants, terbufos sulfone, had only a 

single detection. The remaining 11 UCMR 2 contaminants had multiple detections in small 

and/or large systems.

Additional occurrence findings are contained in Appendix A, B, C, and D. Appendix A 

provides detailed occurrence findings at the level of samples, systems, and population served for 

all UCMR 2 contaminants (including contaminants that had no detections). In Appendix B, the 

number of systems that monitored for each UCMR 2 contaminant, the number of samples taken

at those systems, and the population served by the systems are listed and broken out by state.

Appendix C includes more detailed occurrence numbers for the 12 UCMR 2 contaminants with 

detections, including summary statistics by source water type and system size and the number 

and percentage of samples that exceeded the HRL. Appendix D presents the July 2011 UCMR 2

occurrence numbers (i.e., the data submitted through June 2011, on which the preliminary

Regulatory Determination 3 was based) for all 25 UCMR 2 contaminants.
Occurrence Data from the UCMR 2

August 

2013

25

Exhibit 5-1: Summary of Stage 1 Occurrence Results for 10 Assessment Monitoring 

Contaminants and 15 Screening Survey Contaminants: Sample-Level Results 

Contaminant

Samples Detected Concentration

Number of 

Samples

Detections Minimum

(μg/L)

Median

(μg/L)

Maximum

(μg/L)

Number Percent

Assessment Monitoring Contaminants

BDE-47 32,149 0 0.00% ND ND ND

BDE-99 32,149 0 0.00% ND ND ND

BDE-100 32,149 0 0.00% ND ND ND

BDE-153 32,139 0 0.00% ND ND ND

Dimethoate 32,150 0 0.00% ND ND ND

1,3-Dinitrobenzene 32,152 0 0.00% ND ND ND

HBB 32,143 0 0.00% ND ND ND

RDX 32,150 4 0.01% 1 1.1 1.1

Terbufos sulfone 32,149 1 0.003% 0.42 0.42 0.42

TNT 32,151 0 0.00% ND ND ND

Screening Survey Contaminants

Acetochlor 11,193 0 0.00% ND ND ND

Acetochlor ESA 11,157 2 0.02% 1.10526 1.15263 1.2

Acetochlor OA 11,157 0 0.00% ND ND ND

Alachlor 11,193 0 0.00% ND ND ND

Alachlor ESA 11,156 5 0.04% 1 1.2 1.3

Alachlor OA 11,157 0 0.00% ND ND ND

Metolachlor 11,192 3 0.03% 1.152 1.4 2.73235

Metolachlor ESA 11,157 52 0.47% 1 1.44131 3.95455

Metolachlor OA 11,157 3 0.03% 2.502 3.078 3.539

NDBA 18,101 9 0.05% 0.004 0.00666 0.02062

NDEA 18,096 46 0.25% 0.005 0.007 0.1

NDMA 18,098 1,861 10.28% 0.002 0.004 0.63

NDPA 18,107 0 0.00% ND ND ND

NMEA 18,101 3 0.02% 0.0036 0.0045 0.0049

NPYR 18,101 41 0.23% 0.00207 0.0039 0.0238

NOTE: “ND“ indicates no detection of contaminant.
Occurrence Data from the UCMR 2

August 

2013

26

Exhibit 5-2: Summary of Stage 1 Occurrence Results for 10 Assessment Monitoring 

Contaminants and 15 Screening Survey Contaminants: System-Level Results

Contaminant

Systems Population Served

Number 

of 

Systems

Systems with

Detection(s)

Total 

Population 

Served

by Systems

Population Served by 

Systems with

Detection(s)

Number Percent Number Percent

Assessment Monitoring Contaminants

BDE-47 4,140 0 0.00% 229,237,740 0 0.00%

BDE-99 4,140 0 0.00% 229,237,740 0 0.00%

BDE-100 4,140 0 0.00% 229,237,740 0 0.00%

BDE-153 4,140 0 0.00% 229,237,740 0 0.00%

Dimethoate 4,140 0 0.00% 229,237,740 0 0.00%

1,3-Dinitrobenzene 4,139 0 0.00% 229,225,740 0 0.00%

HBB 4,140 0 0.00% 229,237,740 0 0.00%

RDX 4,139 3 0.07% 229,225,740 96,033 0.04%

Terbufos sulfone 4,140 1 0.02% 229,237,740 44,600 0.02%

TNT 4,139 0 0.00% 229,225,740 0 0.00%

Screening Survey Contaminants

Acetochlor 1,198 0 0.00% 157,219,620 0 0.00%

Acetochlor ESA 1,198 2 0.17% 157,219,620 3,832,155 2.44%

Acetochlor OA 1,198 0 0.00% 157,219,620 0 0.00%

Alachlor 1,198 0 0.00% 157,219,620 0 0.00%

Alachlor ESA 1,198 3 0.25% 157,219,620 3,910,398 2.49%

Alachlor OA 1,198 0 0.00% 157,219,620 0 0.00%

Metolachlor 1,198 3 0.25% 157,219,620 107,510 0.07%

Metolachlor ESA 1,198 19 1.59% 157,219,620 5,873,985 3.74%

Metolachlor OA 1,198 1 0.08% 157,219,620 1,045,522 0.67%

NDBA 1,198 5 0.42% 157,219,620 1,685,983 1.07%

NDEA 1,198 26 2.17% 157,219,620 11,232,194 7.14%

NDMA 1,198 324 27.05% 157,219,620 65,311,764 41.54%

NDPA 1,198 0 0.00% 157,219,620 0 0.00%

NMEA 1,198 3 0.25% 157,219,620 4,480 0.003%

NPYR 1,198 21 1.75% 157,219,620 7,431,551 4.73%
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

27

5.1 Assessment Monitoring Contaminants

This section presents summaries of occurrence results for Assessment Monitoring 

contaminants with at least one detection. In the final UCMR 2 data set, only 2 of the 10 

Assessment Monitoring contaminants had at least one detection – RDX and terbufos sulfone. See 

Exhibit 2-1 for the list of Assessment Monitoring contaminants, and their applicable methods 

and MRLs. The following two sections present detailed occurrence findings on those 

contaminants. The remaining eight Assessment Monitoring contaminants did not have any 

detections (BDE-47, BDE-99, BDE-100, BDE-153, dimethoate, 1,3-dinitrobenzene, HBB, and 

TNT); see Exhibit 5-1, Exhibit 5-2, and Appendix A. The number of systems and samples, by 

state, are included for all 10 Assessment Monitoring contaminants in Appendix B. 

5.1.1 RDX

Under UCMR 2 Assessment Monitoring, 32,150 samples of RDX were collected from 

4,139 PWSs. Of these, 4 samples (0.01%) had analytical detections of RDX at or above the MRL 

of 1 μg/L. The maximum detected concentration of RDX was 1.1 μg/L and the median value was 

also 1.1 μg/L. Appendix C includes more detailed occurrence numbers for RDX, such as 

summary statistics by source water type and system size and the number and percentage of 

samples relative to the HRL. 

The four RDX detections occurred in 3 large surface water systems (0.10%) in 2 states 

(Tennessee and Texas). These systems served a combined population of 96,033 people, or 

0.11%, of the national total population served by water systems of the same size. The percentage 

of all small, large, and very large UCMR 2 Assessment Monitoring systems with at least one 

detection of RDX was 0.07%. A summary of the number of systems with RDX detections and 

the population served by them is presented in Exhibit 5-3.

The design of the UCMR 2 Assessment Monitoring enables extrapolation of national 

estimates of occurrence of contaminants detected in small water systems (see Section 4.3.3). 

Occurrence results from the large and very large systems are already nationally representative so 

national extrapolations are not necessary. These findings suggest that an estimated 3 PWSs 

serving approximately 96,000 customers nationally have RDX detections.

Exhibit 5-3: RDX National Occurrence Measures from UCMR 2

Assessment Monitoring Data - Summary of System and Population Served Data -

All Detections

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections in the 

UCMR 2 Sample

National Inventory 

National Estimate1 of 

the Number (and 

Percent) of Detections

Systems Population Systems Population Systems Population Systems Population

Small Systems (serving ≤ 10,000 people)

Ground Water 618 1,790,743

0 0

57,818 37,685,557

0 0

(0%) (0%) (0%) (0%)
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

28

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections in the 

UCMR 2 Sample

National Inventory 

National Estimate1 of 

the Number (and 

Percent) of Detections

Systems Population Systems Population Systems Population Systems Population

Surface Water 182 878,262

0 0

3,866 8,928,745

0 0

(0%) (0%) (0%) (0%)

All Small 

Systems 800 2,669,004

0 0

61,684 46,614,302

0 0

(0%) (0%) (0%) (0%)

Large Systems (serving 10,001 - 100,000 people) -- CENSUS

Ground Water 1,373 34,816,693

0 0

1,373 34,816,693

0 0

(0%) (0%) (0%) (0%)

Surface Water 1,568 49,758,358

3 96,033

1,568 49,758,358

3 96,033

(0.19%) (0.19%) (0.19%) (0.19%)

All Large 

Systems 2,941 84,575,051

3 96,033

2,941 84,575,051

3 96,033

(0.1%) (0.11%) (0.1%) (0.11%)

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919

0 0

63 17,269,919

0 0

(0%) (0%) (0%) (0%)

Surface Water 335 124,711,765

0 0

335 124,711,765

0 0

(0%) (0%) (0%) (0%)

All Very Large 

Systems 398 141,981,684

0 0

398 141,981,684

0 0

(0%) (0%) (0%) (0%)

All Systems

All Water 

Systems 4,139 229,225,740

3 96,033

65,023 273,171,037

3 96,033

(0.07%) (0.04%) (0.005%) (0.04%)

1 National estimates for the small systems are extrapolations, generated by multiplying the UCMR 2 national statistical sample 

findings of system/population percentages and national system/population inventory numbers for PWSs developed from EPA’s 

SDWIS, the CWSS, and UCMR. National estimates for the large and very large systems are based directly on the UCMR 2 results, 

since this was a census, i.e., all large and very large systems were required to conduct UCMR 2 Assessment Monitoring. Due to 

rounding, some calculations may appear to be incorrect.

RDX was evaluated relative to an HRL of 21 μg/L. None of the RDX detections 

exceeded the one-half HRL (10.5 μg/L) or the full HRL (21 μg/L); thus no occurrence tables 

relative to the HRL are included below. 

5.1.2 Terbufos Sulfone

Under UCMR 2 Assessment Monitoring, 32,149 samples of terbufos sulfone were 

collected from 4,140 PWSs. Of these, a single sample (0.003% of all samples) had an analytical 

detection of terbufos sulfone at or above the MRL of 0.4 μg/L (therefore above the HRL). The 

single detected concentration of terbufos sulfone was equal to 0.42 μg/L. Appendix C includes 

more detailed occurrence numbers for terbufos sulfone, such as summary statistics by source 

water type and system size and the number and percentage of samples relative to the HRL. 
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

29

The terbufos sulfone detection occurred in a single large ground water system (0.02% of 

all systems sampled for terbufos sulfone) in the State of New York. This system served a 

population of 44,600 people or 0.05% of the national total population served by water systems of 

the same size. The percentage of all small, large, and very large UCMR 2 Assessment 

Monitoring systems with at least one detection of terbufos sulfone was 0.02%. A summary of the 

number of systems with detections and the population served by them is presented in Exhibit 5-4. 

As described previously, the design of the UCMR 2 Assessment Monitoring enables 

national extrapolation of estimates of contaminant occurrence in small water systems (see 

Section 4.3.3). Occurrence results from the large and very large systems are already nationally 

representative so national extrapolations are not necessary. These findings suggest that one PWS 

serving approximately 44,600 nationally has detected terbufos sulfone.

Exhibit 5-4: Terbufos Sulfone National Occurrence Measures from UCMR 2

Assessment Monitoring Data - Summary of System and Population Served Data -

All Detections

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections

Systems Population Systems Population Systems Population Systems Population

Small Systems (serving ≤ 10,000 people)

Ground Water 618 1,790,743

0 0

57,818 37,685,557

0 0

(0%) (0%) (0%) (0%)

Surface Water 182 878,262

0 0

3,866 8,928,745

0 0

(0%) (0%) (0%) (0%)

All Small 

Systems 800 2,669,004

0 0

61,684 46,614,302

0 0

(0%) (0%) (0%) (0%)

Large Systems (serving 10,001 - 100,000 people) -- CENSUS

Ground Water 1,374 34,828,693

1 44,600

1,374 34,828,693

1 44,600

(0.07%) (0.13%) (0.07%) (0.13%)

Surface Water 1,568 49,758,358

0 0

1,568 49,758,358

0 0

(0%) (0%) (0%) (0%)

All Large 

Systems 2,942 84,587,051

1 44,600

2,942 84,587,051

1 44,600

(0.03%) (0.05%) (0.03%) (0.05%)

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919

0 0

63 17,269,919

0 0

(0%) (0%) (0%) (0%)

Surface Water 335 124,711,765

0 0

335 124,711,765

0 0

(0%) (0%) (0%) (0%)

All Very Large 

Systems 398 141,981,684

0 0

398 141,981,684

0 0

(0%) (0%) (0%) (0%)
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

30

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections

Systems Population Systems Population Systems Population Systems Population

All Systems

All Water 

Systems 4,140 229,237,740

1 44,600

65,024 273,183,037

1 44,600

(0.02%) (0.02%) (0.002%) (0.02%)

1 National estimates for the small systems are extrapolations generated by multiplying the UCMR 2 national statistical sample 

findings of system/population percentages by the national system/population inventory numbers for PWSs developed from EPA’s 

SDWIS, the CWSS, and UCMR. National estimates for the large and very large systems are based directly on the UCMR 2 results, 

since this was a census, i.e., all large and very large systems were required to conduct UCMR 2 Assessment Monitoring. See 

Section 4.3.3 for a full description of national extrapolations. Due to rounding, some calculations may appear to be incorrect.

Terbufos sulfone was evaluated relative to an HRL of 0.35 μg/L. Exhibit 5-5 and Exhibit 

5-6 present the number of systems and the population they serve with detections greater than 

one-half the HRL and the HRL, respectively. The single detection of terbufos sulfone was equal 

to 0.42 μg/L, which exceeds one-half the HRL and the HRL. These findings suggest that an 

estimated one PWS serving 44,600 people nationally has terbufos sulfone detections greater than 

one-half the HRL and the HRL. (Note that the estimates of national exceedance of these health 

thresholds are identical to the estimated terbufos sulfone national occurrence presented in Exhibit 

5-4 above, since the single detection of terbufos sulfone was greater than the HRL.)

Exhibit 5-5: Terbufos Sulfone National Occurrence Measures from UCMR 2

Assessment Monitoring Data - Summary of System and Population Served Data -

Detections > 1⁄2 HRL

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections > 1/2 HRL 

(0.175 μg/L) in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections > 

1/2 HRL (0.175 μg/L)

Systems Population Systems Population Systems Population Systems Population

Small Systems (serving ≤ 10,000 people)

Ground Water 618 1,790,743

0 0

57,818 37,685,557

0 0

(0%) (0%) (0%) (0%)

Surface Water 182 878,262

0 0

3,866 8,928,745

0 0

(0%) (0%) (0%) (0%)

All Small 

Systems 800 2,669,004

0 0

61,684 46,614,302

0 0

(0%) (0%) (0%) (0%)

Large Systems (serving 10,001 - 100,000 people) -- CENSUS

Ground Water 1,374 34,828,693

1 44,600

1,374 34,828,693

1 44,600

(0.07%) (0.13%) (0.07%) (0.13%)

Surface Water 1,568 49,758,358

0 0

1,568 49,758,358

0 0

(0%) (0%) (0%) (0%)
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

31

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections > 1/2 HRL 

(0.175 μg/L) in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections > 

1/2 HRL (0.175 μg/L)

Systems Population Systems Population Systems Population Systems Population

All Large 

Systems 2,942 84,587,051

1 44,600

2,942 84,587,051

1 44,600

(0.03%) (0.05%) (0.03%) (0.05%)

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919

0 0

63 17,269,919

0 0

(0%) (0%) (0%) (0%)

Surface Water 335 124,711,765

0 0

335 124,711,765

0 0

(0%) (0%) (0%) (0%)

All Very Large 

Systems 398 141,981,684

0 0

398 141,981,684

0 0

(0%) (0%) (0%) (0%)

All Systems

All Water 

Systems 4,140 229,237,740

1 44,600

65,024 273,183,037

1 44,600

(0.02%) (0.02%) (0.002%) (0.02%)

1 National estimates for the small systems are extrapolations generated by multiplying the UCMR 2 national statistical sample 

findings of system/population percentages by the national system/population inventory numbers for PWSs developed from EPA’s 

SDWIS, the CWSS, and UCMR. National estimates for the large and very large systems are based directly on the UCMR 2 results, 

since this was a census, i.e., all large and very large systems were required to conduct UCMR 2 Assessment Monitoring. See 

Section 4.3.3 for a full description of national extrapolations. Due to rounding, some calculations may appear to be incorrect.

Exhibit 5-6: Terbufos Sulfone National Occurrence Measures from UCMR 2

Assessment Monitoring Data - Summary of System and Population Served Data -

Detections > HRL

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections > HRL 

(0.35 μg/L) in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections > 

HRL (0.35 μg/L)

Systems Population Systems Population Systems Population Systems Population

Small Systems (serving ≤ 10,000 people)

Ground Water 618 1,790,743

0 0

57,818 37,685,557

0 0

(0%) (0%) (0%) (0%)

Surface Water 182 878,262

0 0

3,866 8,928,745

0 0

(0%) (0%) (0%) (0%)

All Small 

Systems 800 2,669,004

0 0

61,684 46,614,302

0 0

(0%) (0%) (0%) (0%)

Large Systems (serving 10,001 - 100,000 people) -- CENSUS

Ground Water 1,374 34,828,693

1 44,600

1,374 34,828,693

1 44,600

(0.07%) (0.13%) (0.07%) (0.13%)

Surface Water 1,568 49,758,358

0 0

1,568 49,758,358

0 0

(0%) (0%) (0%) (0%)
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

32

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections > HRL 

(0.35 μg/L) in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections > 

HRL (0.35 μg/L)

Systems Population Systems Population Systems Population Systems Population

All Large 

Systems 2,942 84,587,051

1 44,600

2,942 84,587,051

1 44,600

(0.03%) (0.05%) (0.03%) (0.05%)

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919

0 0

63 17,269,919

0 0

(0%) (0%) (0%) (0%)

Surface Water 335 124,711,765

0 0

335 124,711,765

0 0

(0%) (0%) (0%) (0%)

All Very Large 

Systems 398 141,981,684

0 0

398 141,981,684

0 0

(0%) (0%) (0%) (0%)

All Systems

All Water 

Systems 4,140 229,237,740

1 44,600

65,024 273,183,037

1 44,600

(0.02%) (0.02%) (0.002%) (0.02%)

1 National estimates for the small systems are extrapolations generated by multiplying the UCMR 2 national statistical sample 

findings of system/population percentages by the national system/population inventory numbers for PWSs developed from EPA’s 

SDWIS, the CWSS, and UCMR. National estimates for the large and very large systems are based directly on the UCMR 2 results, 

since this was a census, i.e., all large and very large systems were required to conduct UCMR 2 Assessment Monitoring. See 

Section 4.3.3 for a full description of national extrapolations. Due to rounding, some calculations may appear to be incorrect.

5.2 Screening Survey Contaminants with Detections

This section presents summaries of occurrence results for Screening Survey contaminants 

with at least one detection. In the final UCMR 2 data set, 10 of the 15 Screening Survey

contaminants had at least one detection. See Exhibit 2-1 for the list of Screening Survey

contaminants, and their applicable analytical methods and MRLs. The following 10 subsections 

present detailed occurrence findings on those contaminants. UCMR 2 monitoring found no 

analytical detections for five Screening Survey contaminants (acetochlor, acetochlor OA, 

alachlor, alachlor OA, and NDPA); as such these contaminants are not discussed in more detail 

here. Summary occurrence findings for these contaminants are presented in Exhibit 5-1, Exhibit 

5-2, and Appendix A. Counts of the number of systems and samples, by state, are included for all 

15 Screening Survey contaminants in Appendix B.

5.2.1 Acetochlor ESA

Under the UCMR 2 Screening Survey, 11,157 samples of acetochlor ESA were collected 

from 1,198 PWSs. Of these, 2 (0.02%) samples had analytical detections of acetochlor ESA at or 

above the MRL of 1 μg/L. The maximum detected concentration of acetochlor ESA was 1.2 

μg/L, and the median value was 1.15263 μg/L. Appendix C includes more detailed occurrence 

numbers for acetochlor ESA, such as summary statistics by source water type and system size 

and the number and percentage of samples relative to the HRL.
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

33

One acetochlor ESA detection occurred in a small surface water system in Ohio; the other 

acetochlor ESA detection occurred in a very large surface water system in California. These two 

systems served a cumulative population of 3,832,155 people or 2.44% of the total population 

served by UCMR 2 Screening Survey PWSs. The percentage of all small, large, and very large 

UCMR 2 Screening Survey systems with at least one detection of acetochlor ESA was 0.17%. A 

summary of the number of systems with detections and the population served by them are 

presented in Exhibit 5-7. 

The design of the UCMR 2 Screening Survey enables extrapolation of national estimates 

of occurrence of contaminants detected in small and large water systems (see Section 4.3.3). 

Occurrence results from the very large systems are already nationally representative so national 

extrapolations are not necessary.

Acetochlor ESA is estimated to occur nationally in 16 small systems serving an estimated 

46,701 people. Acetochlor ESA also occurred in one very large system serving 3,828,700 people. 

These findings suggest that an estimated 17 PWSs serving approximately 3.9 million people 

nationally have acetochlor ESA detections.

Exhibit 5-7: Acetochlor ESA National Occurrence Measures from UCMR 2

Screening Survey Data - Summary of System and Population Served Data -

All Detections

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections

Systems Population Systems Population Systems Population Systems Population

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364

0 0

57,818 37,685,557

0 0

(0%) (0%) (0%) (0%)

Surface Water 240 660,557

1 3,455

3,866 8,928,745

16 46,701

(0.42%) (0.52%) (0.42%) (0.52%)

All Small 

Systems 480 1,208,921

1 3,455

61,684 46,614,302

16 46,701

(0.21%) (0.29%) (0.03%) (0.1%)

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184

0 0

1,506 38,870,272

0 0

(0%) (0%) (0%) (0%)

Surface Water 169 7,444,830

0 0

1,366 44,536,172

0 0

(0%) (0%) (0%) (0%)

All Large 

Systems 320 14,029,015

0 0

2,872 83,406,444

0 0

(0%) (0%) (0%) (0%)

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919

0 0

63 17,269,919

0 0

(0%) (0%) (0%) (0%)
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

34

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections

Systems Population Systems Population Systems Population Systems Population

Surface Water 335 124,711,765

1 3,828,700

335 124,711,765

1 3,828,700

(0.3%) (3.07%) (0.3%) (3.07%)

All Very Large 

Systems 398 141,981,684

1 3,828,700

398 141,981,684

1 3,828,700

(0.25%) (2.7%) (0.25%) (2.7%)

All Systems

All Water 

Systems 1,198 157,219,620

2 3,832,155

64,954 272,002,430

17 3,875,401

(0.17%) (2.44%) (0.03%) (1.42%)

1 National estimates for the small and large systems are extrapolations generated by multiplying the UCMR 2 national statistical 

sample findings of system/population percentages by the national system/population inventory numbers for PWSs developed from 

EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems are based directly on the UCMR 2 results, 

since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey. See Section 4.3.3 for a full 

description of national extrapolations. Due to rounding, some calculations may appear to be incorrect.

Acetochlor ESA was evaluated relative to an HRL of 1 μg/L. Exhibit 5-8 and Exhibit 5-9

present the number of systems and the population they serve with detections greater than onehalf the HRL (0.5 μg/L) and the HRL (1 μg/L), respectively. 

Nationally, acetochlor ESA is estimated to exceed one-half the HRL and the HRL in 16 

small systems serving an estimated 46,701 people. Acetochlor ESA also exceeded one-half the 

HRL and the HRL in one very large system serving 3,828,700 people. Therefore, an estimated 

17 PWSs serving approximately 3.9 million people nationally are expected to have acetochlor 

ESA detections greater than one-half the HRL and the HRL. (Note that since all of the acetochlor 

ESA detections are greater than the HRL of 1 μg/L, the estimates of national exceedance of onehalf the HRL and the HRL are identical to the estimated acetochlor ESA national occurrence 

presented in Exhibit 5-7 above.)

Exhibit 5-8: Acetochlor ESA National Occurrence Measures from UCMR 2

Screening Survey Data - Summary of System and Population Served Data -

Detections > 1⁄2 HRL

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections > 1/2 HRL 

(0.5 μg/L) in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections 

> 1/2 HRL (0.5 μg/L)

Systems Population Systems Population Systems Population Systems Population

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364

0 0

57,818 37,685,557

0 0

(0%) (0%) (0%) (0%)

Surface Water 240 660,557

1 3,455

3,866 8,928,745

16 46,701

(0.42%) (0.52%) (0.42%) (0.52%)
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

35

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections > 1/2 HRL 

(0.5 μg/L) in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections 

> 1/2 HRL (0.5 μg/L)

Systems Population Systems Population Systems Population Systems Population

All Small 

Systems 480 1,208,921

1 3,455

61,684 46,614,302

16 46,701

(0.21%) (0.29%) (0.03%) (0.1%)

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184

0 0

1,506 38,870,272

0 0

(0%) (0%) (0%) (0%)

Surface Water 169 7,444,830

0 0

1,366 44,536,172

0 0

(0%) (0%) (0%) (0%)

All Large 

Systems 320 14,029,015

0 0

2,872 83,406,444

0 0

(0%) (0%) (0%) (0%)

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919

0 0

63 17,269,919

0 0

(0%) (0%) (0%) (0%)

Surface Water 335 124,711,765

1 3,828,700

335 124,711,765

1 3,828,700

(0.3%) (3.07%) (0.3%) (3.07%)

All Very Large 

Systems 398 141,981,684

1 3,828,700

398 141,981,684

1 3,828,700

(0.25%) (2.7%) (0.25%) (2.7%)

All Systems

All Water 

Systems 1,198 157,219,620

2 3,832,155

64,954 272,002,430

17 3,875,401

(0.17%) (2.44%) (0.03%) (1.42%)

1 National estimates for the small and large systems are extrapolations generated by multiplying the UCMR 2 national statistical 

sample findings of system/population percentages by the national system/population inventory numbers for PWSs developed from 

EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems are based directly on the UCMR 2 results, 

since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey. See Section 4.3.3 for a full 

description of national extrapolations. Due to rounding, some calculations may appear to be incorrect.

Exhibit 5-9: Acetochlor ESA National Occurrence Measures from UCMR 2

Screening Survey Data - Summary of System and Population Served Data -

Detections > HRL

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections > HRL 

(1 μg/L) in the UCMR 2

Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections 

> HRL (1 μg/L)

Systems Population Systems Population Systems Population Systems Population

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364

0 0

57,818 37,685,557

0 0

(0%) (0%) (0%) (0%)

Surface Water 240 660,557

1 3,455

3,866 8,928,745

16 46,701

(0.42%) (0.52%) (0.42%) (0.52%)
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

36

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections > HRL 

(1 μg/L) in the UCMR 2

Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections 

> HRL (1 μg/L)

Systems Population Systems Population Systems Population Systems Population

All Small 

Systems 480 1,208,921

1 3,455

61,684 46,614,302

16 46,701

(0.21%) (0.29%) (0.03%) (0.1%)

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184

0 0

1,506 38,870,272

0 0

(0%) (0%) (0%) (0%)

Surface Water 169 7,444,830

0 0

1,366 44,536,172

0 0

(0%) (0%) (0%) (0%)

All Large 

Systems 320 14,029,015

0 0

2,872 83,406,444

0 0

(0%) (0%) (0%) (0%)

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919

0 0

63 17,269,919

0 0

(0%) (0%) (0%) (0%)

Surface Water 335 124,711,765

1 3,828,700

335 124,711,765

1 3,828,700

(0.3%) (3.07%) (0.3%) (3.07%)

All Very Large 

Systems 398 141,981,684

1 3,828,700

398 141,981,684

1 3,828,700

(0.25%) (2.7%) (0.25%) (2.7%)

All Systems

All Water 

Systems 1,198 157,219,620

2 3,832,155

64,954 272,002,430

17 3,875,401

(0.17%) (2.44%) (0.03%) (1.42%)

1 National estimates for the small and large systems are extrapolations generated by multiplying the UCMR 2 national statistical 

sample findings of system/population percentages by the national system/population inventory numbers for PWSs developed from 

EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems are based directly on the UCMR 2 results, 

since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey. See Section 4.3.3 for a full 

description of national extrapolations. Due to rounding, some calculations may appear to be incorrect.

5.2.2 Alachlor ESA

Under the UCMR 2 Screening Survey, 11,156 samples of alachlor ESA were collected 

from 1,198 PWSs. Of these, 5 samples (0.04%) had analytical detections of alachlor ESA at or 

above the MRL of 1 μg/L. The maximum detected concentration of alachlor ESA was 1.3 μg/L 

and the median value was 1.2 μg/L. Appendix C includes more detailed occurrence numbers for 

alachlor ESA, such as summary statistics by source water type and system size and the number 

and percentage of samples relative to the HRL.

All but one of the alachlor ESA detections occurred in surface water systems. Alachlor 

ESA was detected in three systems in three states (California, Iowa, and Indiana). The systems 

with detections of alachlor ESA served a cumulative population of 3,910,398 people or 2.49% of 

the total population served by UCMR 2 Screening Survey PWSs. The percentage of all small, 

large, and very large UCMR 2 Screening Survey systems with at least one detection of alachlor 
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

37

ESA was 0.25%. A summary of the number of systems with detections and the population served 

by them are presented in Exhibit 5-10.

The design of the UCMR 2 Screening Survey enables extrapolation of national estimates 

of occurrence of contaminants detected in small and large water systems (see Section 4.3.3). 

Occurrence results from the very large systems are already nationally representative so national 

extrapolations are not necessary.

Alachlor ESA is estimated to occur nationally in 16 small systems serving approximately 

105,000 people. It is also estimated to occur nationally in 10 large systems serving 

approximately 437,000 people. Alachlor ESA also occurred in one very large system serving 

3,828,700 people. These findings suggest that an estimated 27 PWSs serving almost 4.4 million 

people nationally have alachlor ESA detections.

Exhibit 5-10: Alachlor ESA National Occurrence Measures from UCMR 2

Screening Survey Data - Summary of System and Population Served Data - All 

Detections

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections

Systems Population Systems Population Systems Population Systems Population

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364

0 0

57,818 37,685,557

0 0

(0%) (0%) (0%) (0%)

Surface Water 240 660,557

1 7,705

3,866 8,928,745

16 104,148

(0.42%) (1.17%) (0.42%) (1.17%)

All Small 

Systems 480 1,208,921

1 7,705

61,684 46,614,302

16 104,148

(0.21%) (0.64%) (0.03%) (0.22%)

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184

1 73,993

1,506 38,870,272

10 436,824

(0.66%) (1.12%) (0.66%) (1.12%)

Surface Water 169 7,444,830

0 0

1,366 44,536,172

0 0

(0%) (0%) (0%) (0%)

All Large 

Systems 320 14,029,015

1 73,993

2,872 83,406,444

10 436,824

(0.31%) (0.53%) (0.35%) (0.52%)

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919

0 0

63 17,269,919

0 0

(0%) (0%) (0%) (0%)

Surface Water 335 124,711,765

1 3,828,700

335 124,711,765

1 3,828,700

(0.3%) (3.07%) (0.3%) (3.07%)

All Very Large 

Systems 398 141,981,684

1 3,828,700

398 141,981,684

1 3,828,700

(0.25%) (2.7%) (0.25%) (2.7%)
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

38

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections

Systems Population Systems Population Systems Population Systems Population

All Systems

All Water 

Systems 1,198 157,219,620

3 3,910,398

64,954 272,002,430

27 4,369,672

(0.25%) (2.49%) (0.04%) (1.61%)

1 National estimates for the small and large systems are extrapolations generated by multiplying the UCMR 2 national statistical 

sample findings of system/population percentages by the national system/population inventory numbers for PWSs developed from 

EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems are based directly on the UCMR 2 results, 

since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey. See Section 4.3.3 for a full 

description of national extrapolations. Due to rounding, some calculations may appear to be incorrect.

Alachlor ESA was evaluated relative to an HRL of 0.4 μg/L. Exhibit 5-11 and Exhibit 

5-12 present the number of systems and the population they serve with detections greater than 

one-half the HRL (0.2 μg/L) and the HRL (0.4 μg/L), respectively. 

Nationally, alachlor ESA is estimated to exceed one-half the HRL and the HRL in 16 

small systems serving an estimated 104,148 people and 10 large systems serving an estimated 

436,824 people. Alachlor ESA also exceeded one-half the HRL and the HRL in one very large 

system serving 3,828,700 people. These findings suggest that an estimated 27 PWSs serving 

almost 4.4 million people nationally have alachlor ESA detections greater than one-half the HRL 

and the HRL. (Note that since all of the alachlor ESA detections are greater than the HRL of 0.4 

μg/L, the estimates of national exceedance of one-half the HRL and the HRL are identical to the 

estimated alachlor ESA national occurrence presented in Exhibit 5-10 above.)

Exhibit 5-11: Alachlor ESA National Occurrence Measures from UCMR 2

Screening Survey Data - Summary of System and Population Served Data -

Detections > 1⁄2 HRL

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections > 1/2 HRL 

(0.2 μg/L) in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections 

> 1/2 HRL (0.2 μg/L)

Systems Population Systems Population Systems Population Systems Population

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364

0 0

57,818 37,685,557

0 0

(0%) (0%) (0%) (0%)

Surface Water 240 660,557

1 7,705

3,866 8,928,745

16 104,148

(0.42%) (1.17%) (0.42%) (1.17%)

All Small 

Systems 480 1,208,921

1 7,705

61,684 46,614,302

16 104,148

(0.21%) (0.64%) (0.03%) (0.22%)

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184

1 73,993

1,506 38,870,272

10 436,824

(0.66%) (1.12%) (0.66%) (1.12%)

Surface Water 169 7,444,830

0 0

1,366 44,536,172

0 0

(0%) (0%) (0%) (0%)
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

39

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections > 1/2 HRL 

(0.2 μg/L) in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections 

> 1/2 HRL (0.2 μg/L)

Systems Population Systems Population Systems Population Systems Population

All Large 

Systems 320 14,029,015

1 73,993

2,872 83,406,444

10 436,824

(0.31%) (0.53%) (0.35%) (0.52%)

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919

0 0

63 17,269,919

0 0

(0%) (0%) (0%) (0%)

Surface Water 335 124,711,765

1 3,828,700

335 124,711,765

1 3,828,700

(0.3%) (3.07%) (0.3%) (3.07%)

All Very Large 

Systems 398 141,981,684

1 3,828,700

398 141,981,684

1 3,828,700

(0.25%) (2.7%) (0.25%) (2.7%)

All Systems

All Water 

Systems 1,198 157,219,620

3 3,910,398

64,954 272,002,430

27 4,369,672

(0.25%) (2.49%) (0.04%) (1.61%)

1 National estimates for the small and large systems are extrapolations generated by multiplying the UCMR 2 national statistical 

sample findings of system/population percentages by the national system/population inventory numbers for PWSs developed from 

EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems are based directly on the UCMR 2 results, 

since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey. See Section 4.3.3 for a full 

description of national extrapolations. Due to rounding, some calculations may appear to be incorrect.

Exhibit 5-12: Alachlor ESA National Occurrence Measures from UCMR 2

Screening Survey Data - Summary of System and Population Served Data -

Detections > HRL

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections > HRL 

(0.4 μg/L) in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections 

> HRL (0.4 μg/L)

Systems Population Systems Population Systems Population Systems Population

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364

0 0

57,818 37,685,557

0 0

(0%) (0%) (0%) (0%)

Surface Water 240 660,557

1 7,705

3,866 8,928,745

16 104,148

(0.42%) (1.17%) (0.42%) (1.17%)

All Small 

Systems 480 1,208,921

1 7,705

61,684 46,614,302

16 104,148

(0.21%) (0.64%) (0.03%) (0.22%)

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184

1 73,993

1,506 38,870,272

10 436,824

(0.66%) (1.12%) (0.66%) (1.12%)

Surface Water 169 7,444,830

0 0

1,366 44,536,172

0 0

(0%) (0%) (0%) (0%)

All Large 

Systems 320 14,029,015

1 73,993

2,872 83,406,444

10 436,824

(0.31%) (0.53%) (0.35%) (0.52%)
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

40

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections > HRL 

(0.4 μg/L) in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections 

> HRL (0.4 μg/L)

Systems Population Systems Population Systems Population Systems Population

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919

0 0

63 17,269,919

0 0

(0%) (0%) (0%) (0%)

Surface Water 335 124,711,765

1 3,828,700

335 124,711,765

1 3,828,700

(0.3%) (3.07%) (0.3%) (3.07%)

All Very Large 

Systems 398 141,981,684

1 3,828,700

398 141,981,684

1 3,828,700

(0.25%) (2.7%) (0.25%) (2.7%)

All Systems

All Water 

Systems 1,198 157,219,620

3 3,910,398

64,954 272,002,430

27 4,369,672

(0.25%) (2.49%) (0.04%) (1.61%)

1 National estimates for the small and large systems are extrapolations generated by multiplying the UCMR 2 national statistical 

sample findings of system/population percentages by the national system/population inventory numbers for PWSs developed from 

EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems are based directly on the UCMR 2 results, 

since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey. See Section 4.3.3 for a full 

description of national extrapolations. Due to rounding, some calculations may appear to be incorrect.

5.2.3 Metolachlor

Under the UCMR 2 Screening Survey, 11,192 samples of metolachlor were collected 

from 1,198 PWSs. Of these, 3 samples (0.03%) had analytical detections of metolachlor at or 

above the MRL of 1 μg/L. The maximum detected concentration of metolachlor was 2.73235

μg/L and the median value was 1.4 μg/L. Appendix C includes more detailed occurrence 

numbers for metolachlor, such as summary statistics by source water type and system size.

All three metolachlor detections occurred in surface water systems, of which two 

detections were small systems and one was a very large system, in three states (Delaware, 

Indiana, and Oklahoma). These systems served a cumulative population of 107,510 people or 

0.07% of the total population served by UCMR 2 Screening Survey PWSs. The percentage of all 

small, large, and very large UCMR 2 Screening Survey systems with at least one detection of 

metolachlor was 0.25%. A summary of the number of systems with detections and the population 

served by them are presented in Exhibit 5-13.

The design of the UCMR 2 Screening Survey enables extrapolation of national estimates 

of occurrence of contaminants detected in small and large water systems (see Section 4.3.3). 

Occurrence results from the very large systems are already nationally representative so national 

extrapolations are not necessary.

Metolachlor is estimated to occur nationally in 32 small systems serving approximately 

30,000 people. Metolachlor also occurred in one very large system serving 105,270 people. 

These findings suggest that an estimated 33 PWSs serving approximately 136,000 people 

nationally have metolachlor detections. 
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

41

Exhibit 5-13: Metolachlor National Occurrence Measures from UCMR 2 Screening 

Survey Data - Summary of System and Population Served Data - All Detections

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections

Systems Population Systems Population Systems Population Systems Population

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364

0 0

57,818 37,685,557

0 0

(0%) (0%) (0%) (0%)

Surface Water 240 660,557

2 2,240

3,866 8,928,745

32 30,278

(0.83%) (0.34%) (0.83%) (0.34%)

All Small 

Systems 480 1,208,921

2 2,240

61,684 46,614,302

32 30,278

(0.42%) (0.19%) (0.05%) (0.06%)

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184

0 0

1,506 38,870,272

0 0

(0%) (0%) (0%) (0%)

Surface Water 169 7,444,830

0 0

1,366 44,536,172

0 0

(0%) (0%) (0%) (0%)

All Large 

Systems 320 14,029,015

0 0

2,872 83,406,444

0 0

(0%) (0%) (0%) (0%)

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919

0 0

63 17,269,919

0 0

(0%) (0%) (0%) (0%)

Surface Water 335 124,711,765

1 105,270

335 124,711,765

1 105,270

(0.3%) (0.08%) (0.3%) (0.08%)

All Very Large 

Systems 398 141,981,684

1 105,270

398 141,981,684

1 105,270

(0.25%) (0.07%) (0.25%) (0.07%)

All Systems

All Water 

Systems 1,198 157,219,620

3 107,510

64,954 272,002,430

33 135,548

(0.25%) (0.07%) (0.05%) (0.05%)

1 National estimates for the small and large systems are extrapolations generated by multiplying the UCMR 2 national statistical 

sample findings of system/population percentages by the national system/population inventory numbers for PWSs developed from 

EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems are based directly on the UCMR 2 results, 

since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey. See Section 4.3.3 for a full 

description of national extrapolations. Due to rounding, some calculations may appear to be incorrect.

Metolachlor was evaluated relative to an HRL of 700 μg/L. None of the metolachlor 

detections exceeded one-half the HRL (350 μg/L) or the HRL (700 μg/L); thus no occurrence 

tables relative to the HRL are included below.
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

42

5.2.4 Metolachlor ESA

Under the UCMR 2 Screening Survey, 11,157 samples of metolachlor ESA were 

collected from 1,198 PWSs. Of these, 52 samples (0.47%) had analytical detections of 

metolachlor ESA at or above the MRL of 1 μg/L. The maximum detected concentration of 

metolachlor ESA was 3.95455 μg/L and the median value was 1.44131 μg/L. Appendix C 

includes more detailed occurrence numbers for metolachlor ESA, such as summary statistics by 

source water type and system size.

Detections of metolachlor ESA occurred in 7 ground water and 12 surface water systems 

in 10 states. These 19 systems served a cumulative population of approximately 5.9 million 

people or 3.74% of the total population served by UCMR 2 Screening Survey PWSs. The 

percentage of all small, large, and very large UCMR 2 Screening Survey systems with at least 

one detection of metolachlor ESA was 1.59%. A summary of the number of systems with 

detections and the population served by them are presented in Exhibit 5-14.

The design of the UCMR 2 Screening Survey enables extrapolation of national estimates 

of occurrence of contaminants detected in small and large water systems (see Section 4.3.3). 

Occurrence results from the very large systems are already nationally representative so national 

extrapolations are not necessary.

Metolachlor ESA is estimated to occur nationally in 1,253 small systems serving an 

estimated population of approximately 1.4 million people. It is also estimated to occur nationally 

in 34 large systems serving an estimated cumulative population of approximately 1.3 million 

people. Metolachlor ESA also occurred in 7 very large systems serving 5.6 million people. These 

findings suggest that an estimated 1,294 PWSs serving more than 8.3 million people nationally 

have metolachlor ESA detections. 

Exhibit 5-14: Metolachlor ESA National Occurrence Measures from UCMR 2

Screening Survey Data - Summary of System and Population Served Data - All 

Detections

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections

Systems Population Systems Population Systems Population Systems Population

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364

5 17,540

57,818 37,685,557

1,205 1,205,412

(2.08%) (3.2%) (2.08%) (3.2%)

Surface Water 240 660,557

3 17,498

3,866 8,928,745

48 236,514

(1.25%) (2.65%) (1.25%) (2.65%)

All Small 

Systems 480 1,208,921

8 35,038

61,684 46,614,302

1,253 1,441,926

(1.67%) (2.9%) (2.03%) (3.09%)
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

43

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections

Systems Population Systems Population Systems Population Systems Population

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184

1 73,993

1,506 38,870,272

10 436,824

(0.66%) (1.12%) (0.66%) (1.12%)

Surface Water 169 7,444,830

3 138,897

1,366 44,536,172

24 830,904

(1.78%) (1.87%) (1.78%) (1.87%)

All Large 

Systems 320 14,029,015

4 212,890

2,872 83,406,444

34 1,267,728

(1.25%) (1.52%) (1.19%) (1.52%)

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919

1 1,045,522

63 17,269,919

1 1,045,522

(1.59%) (6.05%) (1.59%) (6.05%)

Surface Water 335 124,711,765

6 4,580,535

335 124,711,765

6 4,580,535

(1.79%) (3.67%) (1.79%) (3.67%)

All Very Large 

Systems 398 141,981,684

7 5,626,057

398 141,981,684

7 5,626,057

(1.76%) (3.96%) (1.76%) (3.96%)

All Systems

All Water 

Systems 1,198 157,219,620

19 5,873,985

64,954 272,002,430

1,294 8,335,711

(1.59%) (3.74%) (1.99%) (3.06%)

1 National estimates for the small and large systems are extrapolations generated by multiplying the UCMR 2 national statistical 

sample findings of system/population percentages by the national system/population inventory numbers for PWSs developed from 

EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems are based directly on the UCMR 2 results, 

since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey. See Section 4.3.3 for a full 

description of national extrapolations. Due to rounding, some calculations may appear to be incorrect.

Metolachlor ESA was evaluated relative to an HRL of 700 μg/L. None of the metolachlor 

ESA detections exceeded one-half the HRL (350 μg/L) or the full HRL (700 μg/L); thus no 

occurrence tables relative to the HRL are included below. 

5.2.5 Metolachlor OA

Under the UCMR 2 Screening Survey, 11,157 samples of metolachlor OA were collected 

from 1,198 PWSs. Of these, 3 samples (0.03%) had analytical detections of metolachlor OA at or 

above the MRL of 2 μg/L. The maximum detected concentration of metolachlor OA was 3.539 

μg/L and the median value was 3.078 μg/L. Appendix C includes more detailed occurrence 

numbers for metolachlor OA, such as summary statistics by source water type and system size.

All three metolachlor OA detections occurred in a single very large ground water system 

in the State of New York. This system served a population of approximately 1.05 million people 

or 0.67% of the total population served by UCMR 2 Screening Survey PWSs. The percentage of 

all small, large, and very large UCMR 2 Screening Survey systems with at least one detection of 
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

44

metolachlor OA was 0.08%. A summary of the number of systems with detections and the 

population served by them are presented in Exhibit 5-15.

The design of the UCMR 2 Screening Survey enables extrapolation of national estimates 

of occurrence of contaminants detected in small and large water systems (see Section 4.3.3). 

Occurrence results from the very large systems are already nationally representative so national 

extrapolations are not necessary. These findings suggest that an estimated one PWS serving 1.05 

million people nationally has metolachlor OA detections.

Exhibit 5-15: Metolachlor OA National Occurrence Measures from UCMR 2

Screening Survey Data - Summary of System and Population Served Data - All 

Detections

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections

Systems Population Systems Population Systems Population Systems Population

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364

0 0

57,818 37,685,557

0 0

(0%) (0%) (0%) (0%)

Surface Water 240 660,557

0 0

3,866 8,928,745

0 0

(0%) (0%) (0%) (0%)

All Small 

Systems 480 1,208,921

0 0

61,684 46,614,302

0 0

(0%) (0%) (0%) (0%)

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184

0 0

1,506 38,870,272

0 0

(0%) (0%) (0%) (0%)

Surface Water 169 7,444,830

0 0

1,366 44,536,172

0 0

(0%) (0%) (0%) (0%)

All Large 

Systems 320 14,029,015

0 0

2,872 83,406,444

0 0

(0%) (0%) (0%) (0%)

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919

1 1,045,522

63 17,269,919

1 1,045,522

(1.59%) (6.05%) (1.59%) (6.05%)

Surface Water 335 124,711,765

0 0

335 124,711,765

0 0

(0%) (0%) (0%) (0%)

All Very Large 

Systems 398 141,981,684

1 1,045,522

398 141,981,684

1 1,045,522

(0.25%) (0.74%) (0.25%) (0.74%)

All Systems

All Water 

Systems 1,198 157,219,620

1 1,045,522

64,954 272,002,430

1 1,045,522

(0.08%) (0.67%) (0%) (0.38%)

1 National estimates for the small and large systems are extrapolations generated by multiplying the UCMR 2 national statistical 

sample findings of system/population percentages by the national system/population inventory numbers for PWSs developed from 

EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems are based directly on the UCMR 2 results, 
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

45

since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey. See Section 4.3.3 for a full 

description of national extrapolations. Due to rounding, some calculations may appear to be incorrect.

Metolachlor OA was evaluated relative to an HRL of 700 μg/L. None of the metolachlor 

OA detections exceeded one-half the HRL (350 μg/L) or the HRL (700 μg/L); thus no 

occurrence tables relative to the HRL are included below. 

5.2.6 NDBA

Under the UCMR 2 Screening Survey, 18,101 samples of NDBA were collected from 

1,198 PWSs. Of these, 9 samples (0.05%) had analytical detections of NDBA at or above the 

MRL of 0.004 μg/L. The maximum detected concentration of NDBA was 0.02062 μg/L and the 

median value was 0.00666 μg/L. Appendix C includes more detailed occurrence numbers for 

NDBA, such as summary statistics by source water type and system size.

Detections of NDBA occurred in three ground water and two surface water systems in 

four states. These five systems served a cumulative population of approximately 1.7 million 

people or 1.07% of the total population served by UCMR 2 Screening Survey PWSs. The 

percentage of all small, large, and very large UCMR 2 Screening Survey systems with at least 

one detection of NDBA was 0.42%. A summary of the number of systems with detections and 

the population served by them are presented in Exhibit 5-16.

The design of the UCMR 2 Screening Survey enables extrapolation of national estimates 

of occurrence of contaminants detected in small and large water systems (see Section 4.3.3). 

Occurrence results from the very large systems are already nationally representative so national 

extrapolations are not necessary.

NDBA is estimated to occur nationally in 482 small systems serving approximately 

982,000 people. NDBA also occurred in 3 very large systems serving 1.67 million people. These 

findings suggest that an estimated 485 PWSs serving approximately 2.7 million people 

nationally have NDBA detections.

Exhibit 5-16: NDBA National Occurrence Measures from UCMR 2 Screening 

Survey Data - Summary of System and Population Served Data - All Detections

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections

Systems Population Systems Population Systems Population Systems Population

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364

2 14,292

57,818 37,685,557

482 982,198

(0.83%) (2.61%) (0.83%) (2.61%)

Surface Water 240 660,557

0 0

3,866 8,928,745

0 0

(0%) (0%) (0%) (0%)
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

46

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections

Systems Population Systems Population Systems Population Systems Population

All Small 

Systems 480 1,208,921

2 14,292

61,684 46,614,302

482 982,198

(0.42%) (1.18%) (0.78%) (2.11%)

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184

0 0

1,506 38,870,272

0 0

(0%) (0%) (0%) (0%)

Surface Water 169 7,444,830

0 0

1,366 44,536,172

0 0

(0%) (0%) (0%) (0%)

All Large 

Systems 320 14,029,015

0 0

2,872 83,406,444

0 0

(0%) (0%) (0%) (0%)

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919

1 1,045,522

63 17,269,919

1 1,045,522

(1.59%) (6.05%) (1.59%) (6.05%)

Surface Water 335 124,711,765

2 626,169

335 124,711,765

2 626,169

(0.6%) (0.5%) (0.6%) (0.5%)

All Very Large 

Systems 398 141,981,684

3 1,671,691

398 141,981,684

3 1,671,691

(0.75%) (1.18%) (0.75%) (1.18%)

All Systems

All Water 

Systems 1,198 157,219,620

5 1,685,983

64,954 272,002,430

485 2,653,889

(0.42%) (1.07%) (0.75%) (0.98%)

1 National estimates for the small and large systems are extrapolations generated by multiplying the UCMR 2 national statistical 

sample findings of system/population percentages by the national system/population inventory numbers for PWSs developed from 

EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems are based directly on the UCMR 2 results, 

since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey. See Section 4.3.3 for a full 

description of national extrapolations. Due to rounding, some calculations may appear to be incorrect.

NDBA was evaluated relative to an HRL of 0.03 μg/L. NDBA was evaluated relative to 

an HRL of 0.03 μg/L. Exhibit 5-17 and Exhibit 5-18 present the number of systems and the 

population they serve with detections greater than one-half the HRL and the HRL, respectively. 

Nationally, NDBA is estimated to exceed one-half the HRL in 241 small systems serving 

approximately 467,000 people. There were no exceedances of the HRL.
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

47

Exhibit 5-17: NDBA National Occurrence Measures from UCMR 2 Screening 

Survey Data - Summary of System and Population Served Data - Detections > 1⁄2 

HRL

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections > 1/2 HRL 

(0.015 μg/L) in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections 

> 1/2 HRL (0.015 μg/L)

Systems Population Systems Population Systems Population Systems Population

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364

1 6,792

57,818 37,685,557

241 466,771

(0.42%) (1.24%) (0.42%) (1.24%)

Surface Water 240 660,557

0 0

3,866 8,928,745

0 0

(0%) (0%) (0%) (0%)

All Small 

Systems 480 1,208,921

1 6,792

61,684 46,614,302

241 466,771

(0.21%) (0.56%) (0.39%) (1%)

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184

0 0

1,506 38,870,272

0 0

(0%) (0%) (0%) (0%)

Surface Water 169 7,444,830

0 0

1,366 44,536,172

0 0

(0%) (0%) (0%) (0%)

All Large 

Systems 320 14,029,015

0 0

2,872 83,406,444

0 0

(0%) (0%) (0%) (0%)

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919

0 0

63 17,269,919

0 0

(0%) (0%) (0%) (0%)

Surface Water 335 124,711,765

0 0

335 124,711,765

0 0

(0%) (0%) (0%) (0%)

All Very Large 

Systems 398 141,981,684

0 0

398 141,981,684

0 0

(0%) (0%) (0%) (0%)

All Systems

All Water 

Systems 1,198 157,219,620

1 6,792

64,954 272,002,430

241 466,771

(0.08%) (0.004%) (0.37%) (0.17%)

1 National estimates for the small and large systems are extrapolations generated by multiplying the UCMR 2 national statistical 

sample findings of system/population percentages by the national system/population inventory numbers for PWSs developed from 

EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems are based directly on the UCMR 2 results, 

since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey. See Section 4.3.3 for a full 

description of national extrapolations. Due to rounding, some calculations may appear to be incorrect.
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

48

Exhibit 5-18: NDBA National Occurrence Measures from UCMR 2 Screening 

Survey Data - Summary of System and Population Served Data - Detections > 

HRL

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections > HRL 

(0.03 μg/L) in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections 

> HRL (0.03 μg/L)

Systems Population Systems Population Systems Population Systems Population

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364

0 0

57,818 37,685,557

0 0

(0%) (0%) (0%) (0%)

Surface Water 240 660,557

0 0

3,866 8,928,745

0 0

(0%) (0%) (0%) (0%)

All Small 

Systems 480 1,208,921

0 0

61,684 46,614,302

0 0

(0%) (0%) (0%) (0%)

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184

0 0

1,506 38,870,272

0 0

(0%) (0%) (0%) (0%)

Surface Water 169 7,444,830

0 0

1,366 44,536,172

0 0

(0%) (0%) (0%) (0%)

All Large 

Systems 320 14,029,015

0 0

2,872 83,406,444

0 0

(0%) (0%) (0%) (0%)

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919

0 0

63 17,269,919

0 0

(0%) (0%) (0%) (0%)

Surface Water 335 124,711,765

0 0

335 124,711,765

0 0

(0%) (0%) (0%) (0%)

All Very Large 

Systems 398 141,981,684

0 0

398 141,981,684

0 0

(0%) (0%) (0%) (0%)

All Systems

All Water 

Systems 1,198 157,219,620

0 0

64,954 272,002,430

0 0

(0%) (0%) (0%) (0%)

1 National estimates for the small and large systems are extrapolations generated by multiplying the UCMR 2 national statistical 

sample findings of system/population percentages by the national system/population inventory numbers for PWSs developed from 

EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems are based directly on the UCMR 2 results, 

since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey. See Section 4.3.3 for a full 

description of national extrapolations. Due to rounding, some calculations may appear to be incorrect.

5.2.7 NDEA

Under the UCMR 2 Screening Survey, 18,096 samples of NDEA were collected from 

1,198 PWSs. Of these, 46 (0.25%) samples had analytical detections of NDEA at or above the 

MRL of 0.005 μg/L. The maximum detected concentration of NDEA was 0.1 μg/L and the 

median value was 0.007 μg/L. Appendix C includes more detailed occurrence numbers for 
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

49

NDEA, such as summary statistics by source water type and system size and the number and 

percentage of samples relative to the HRL.

NDEA was detected in seven ground and 19 surface water systems in eight states and one 

territory (Guam). The majority of these detections occurred in very large surface water systems. 

Systems with detections served a cumulative population of approximately 11.2 million people or 

7.14% of the total population served by UCMR 2 Screening Survey PWSs. The percentage of all 

small, large, and very large UCMR 2 Screening Survey systems with at least one detection of 

NDEA was 2.17%. A summary of the number of systems with detections and the population 

served by them are presented in Exhibit 5-19.

The design of the UCMR 2 Screening Survey enables extrapolation of national estimates 

of occurrence of contaminants detected in small and large water systems (see Section 4.3.3). 

Occurrence results from the very large systems are already nationally representative so national 

extrapolations are not necessary.

NDEA is estimated to occur nationally in 241 small systems serving approximately 

452,000 people. It is also estimated to occur nationally in 34 large systems serving an estimated 

population of approximately 1.4 million people. NDEA also occurred in 21 very large systems 

serving approximately 11.0 million people. These findings suggest that an estimated 296 PWSs 

serving approximately 12.9 million people nationally have NDEA detections.

Exhibit 5-19: NDEA National Occurrence Measures from UCMR 2 Screening 

Survey Data - Summary of System and Population Served Data - All Detections

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections

Systems Population Systems Population Systems Population Systems Population

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364

1 6,575

57,818 37,685,557

241 451,858

(0.42%) (1.2%) (0.42%) (1.2%)

Surface Water 240 660,557

0 0

3,866 8,928,745

0 0

(0%) (0%) (0%) (0%)

All Small 

Systems 480 1,208,921

1 6,575

61,684 46,614,302

241 451,858

(0.21%) (0.54%) (0.39%) (0.97%)

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184

1 93,660

1,506 38,870,272

10 552,930

(0.66%) (1.42%) (0.66%) (1.42%)

Surface Water 169 7,444,830

3 148,608

1,366 44,536,172

24 888,995

(1.78%) (2%) (1.78%) (2%)

All Large 

Systems 320 14,029,015

4 242,268

2,872 83,406,444

34 1,441,924

(1.25%) (1.73%) (1.19%) (1.73%)
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

50

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections

Systems Population Systems Population Systems Population Systems Population

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919

5 668,861

63 17,269,919

5 668,861

(7.94%) (3.87%) (7.94%) (3.87%)

Surface Water 335 124,711,765

16 10,314,490

335 124,711,765

16 10,314,490

(4.78%) (8.27%) (4.78%) (8.27%)

All Very Large 

Systems 398 141,981,684

21 10,983,351

398 141,981,684

21 10,983,351

(5.28%) (7.74%) (5.28%) (7.74%)

All Systems

All Water 

Systems 1,198 157,219,620

26 11,232,194

64,954 272,002,430

296 12,877,133

(2.17%) (7.14%) (0.46%) (4.73%)

1 National estimates for the small and large systems are extrapolations generated by multiplying the UCMR 2 national statistical 

sample findings of system/population percentages by the national system/population inventory numbers for PWSs developed from 

EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems are based directly on the UCMR 2 results, 

since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey. See Section 4.3.3 for a full 

description of national extrapolations. Due to rounding, some calculations may appear to be incorrect.

NDEA was evaluated relative to an HRL of 0.0004 μg/L. Exhibit 5-20 and Exhibit 5-21

present the number of systems and the population they serve with detections greater than onehalf the HRL and the HRL, respectively. Nationally, NDEA is estimated to exceed one-half the 

HRL and the HRL in 241 small systems serving approximately 452,000 people and 34 large 

systems serving an estimated 1.4 million people. NDEA also exceeded one-half the HRL and the 

HRL in 21 very large systems serving approximately 11.0 million people. These findings suggest 

that an estimated 296 PWSs serving approximately 12.9 million people nationally have NDEA 

detections. (Note that since all of the NDEA detections are greater than the HRL of 0.0004 μg/L, 

the estimates of national exceedance of one-half the HRL and the HRL are identical to the 

estimated NDEA national occurrence presented in Exhibit 5-19 above.)

Exhibit 5-20: NDEA National Occurrence Measures from UCMR 2 Screening 

Survey Data - Summary of System and Population Served Data - Detections > 1⁄2 

HRL

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections > 1/2 HRL 

(0.0002 μg/L) in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections 

> 1/2 HRL (0.0002 μg/L)

Systems Population Systems Population Systems Population Systems Population

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364

1 6,575

57,818 37,685,557

241 451,858

(0.42%) (1.2%) (0.42%) (1.2%)
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

51

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections > 1/2 HRL 

(0.0002 μg/L) in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections 

> 1/2 HRL (0.0002 μg/L)

Systems Population Systems Population Systems Population Systems Population

Surface Water 240 660,557

0 0

3,866 8,928,745

0 0

(0%) (0%) (0%) (0%)

All Small 

Systems 480 1,208,921

1 6,575

61,684 46,614,302

241 451,858

(0.21%) (0.54%) (0.39%) (0.97%)

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184

1 93,660

1,506 38,870,272

10 552,930

(0.66%) (1.42%) (0.66%) (1.42%)

Surface Water 169 7,444,830

3 148,608

1,366 44,536,172

24 888,995

(1.78%) (2%) (1.78%) (2%)

All Large 

Systems 320 14,029,015

4 242,268

2,872 83,406,444

34 1,441,924

(1.25%) (1.73%) (1.19%) (1.73%)

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919

5 668,861

63 17,269,919

5 668,861

(7.94%) (3.87%) (7.94%) (3.87%)

Surface Water 335 124,711,765

16 10,314,490

335 124,711,765

16 10,314,490

(4.78%) (8.27%) (4.78%) (8.27%)

All Very Large 

Systems 398 141,981,684

21 10,983,351

398 141,981,684

21 10,983,351

(5.28%) (7.74%) (5.28%) (7.74%)

All Systems

All Water 

Systems 1,198 157,219,620

26 11,232,194

64,954 272,002,430

296 12,877,133

(2.17%) (7.14%) (0.46%) (4.73%)

1 National estimates for the small and large systems are extrapolations generated by multiplying the UCMR 2 national statistical 

sample findings of system/population percentages by the national system/population inventory numbers for PWSs developed from 

EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems are based directly on the UCMR 2 results, 

since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey. See Section 4.3.3 for a full 

description of national extrapolations. Due to rounding, some calculations may appear to be incorrect.

Exhibit 5-21: NDEA National Occurrence Measures from UCMR 2 Screening 

Survey Data - Summary of System and Population Served Data - Detections > 

HRL

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections > HRL 

(0.0004 μg/L) in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections 

> HRL (0.0004 μg/L)

Systems Population Systems Population Systems Population Systems Population

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364

1 6,575

57,818 37,685,557

241 451,858

(0.42%) (1.2%) (0.42%) (1.2%)
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

52

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections > HRL 

(0.0004 μg/L) in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections 

> HRL (0.0004 μg/L)

Systems Population Systems Population Systems Population Systems Population

Surface Water 240 660,557

0 0

3,866 8,928,745

0 0

(0%) (0%) (0%) (0%)

All Small 

Systems 480 1,208,921

1 6,575

61,684 46,614,302

241 451,858

(0.21%) (0.54%) (0.39%) (0.97%)

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184

1 93,660

1,506 38,870,272

10 552,930

(0.66%) (1.42%) (0.66%) (1.42%)

Surface Water 169 7,444,830

3 148,608

1,366 44,536,172

24 888,995

(1.78%) (2%) (1.78%) (2%)

All Large 

Systems 320 14,029,015

4 242,268

2,872 83,406,444

34 1,441,924

(1.25%) (1.73%) (1.19%) (1.73%)

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919

5 668,861

63 17,269,919

5 668,861

(7.94%) (3.87%) (7.94%) (3.87%)

Surface Water 335 124,711,765

16 10,314,490

335 124,711,765

16 10,314,490

(4.78%) (8.27%) (4.78%) (8.27%)

All Very Large 

Systems 398 141,981,684

21 10,983,351

398 141,981,684

21 10,983,351

(5.28%) (7.74%) (5.28%) (7.74%)

All Systems

All Water 

Systems 1,198 157,219,620

26 11,232,194

64,954 272,002,430

296 12,877,133

(2.17%) (7.14%) (0.46%) (4.73%)

1 National estimates for the small and large systems are extrapolations generated by multiplying the UCMR 2 national statistical 

sample findings of system/population percentages by the national system/population inventory numbers for PWSs developed from 

EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems are based directly on the UCMR 2 results, 

since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey. See Section 4.3.3 for a full 

description of national extrapolations. Due to rounding, some calculations may appear to be incorrect.

5.2.8 NDMA

Under the UCMR 2 Screening Survey, 18,098 samples of NDMA were collected from 

1,198 PWSs. Of these, 1,861 samples (10.3%) had analytical detections of NDMA at or above 

the MRL of 0.002 μg/L. The maximum detected concentration of NDMA was 0.63 μg/L and the 

median value was 0.004 μg/L. Appendix C includes more detailed occurrence numbers for 

NDMA, such as summary statistics by source water type and system size and the number and 

percentage of samples relative to the HRL.

NDMA was detected in 45 states and two territories (Guam and Puerto Rico). The

majority of those detections occurred in surface water systems. The 324 systems with detections 

served a cumulative population of approximately 65.3 million people or 41.54% of the total 

population served by UCMR 2 Screening Survey PWSs. The percentage of all small, large, and 
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

53

very large UCMR 2 Screening Survey systems with at least one detection of NDMA was 

27.05%. A summary of the number of systems with detections and the population served by 

them are presented in Exhibit 5-22.

The design of the UCMR 2 Screening Survey enables extrapolation of national estimates 

of occurrence of contaminants detected in small and large water systems (see Section 4.3.3). 

Occurrence results from the very large systems are already nationally representative so national 

extrapolations are not necessary.

NDMA is estimated to occur nationally in 3,601 small water systems serving an 

estimated 5.3 million people. It is also estimated to occur nationally in 598 large water systems 

of serving an estimated 21.1 million people. NDMA also occurred in 169 very large systems 

serving almost 61.5 million people. These findings suggest that an estimated 4,369 PWSs serving 

approximately 87.9 million people nationally have NDMA detections.

Exhibit 5-22: NDMA National Occurrence Measures from UCMR 2 Screening 

Survey Data - Summary of System and Population Served Data - All Detections

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections

Systems Population Systems Population Systems Population Systems Population

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364

10 26,059

57,818 37,685,557

2,409 1,790,869

(4.17%) (4.75%) (4.17%) (4.75%)

Surface Water 240 660,557

74 259,285

3,866 8,928,745

1,192 3,504,746

(30.83%) (39.25%) (30.83%) (39.25%)

All Small 

Systems 480 1,208,921

84 285,344

61,684 46,614,302

3,601 5,295,615

(17.5%) (23.6%) (5.84%) (11.36%)

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184

13 739,206

1,506 38,870,272

130 4,363,960

(8.61%) (11.23%) (8.61%) (11.23%)

Surface Water 169 7,444,830

58 2,792,925

1,366 44,536,172

469 16,707,724

(34.32%) (37.51%) (34.32%) (37.51%)

All Large 

Systems 320 14,029,015

71 3,532,130

2,872 83,406,444

598 21,071,684

(22.19%) (25.18%) (20.84%) (25.26%)

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919

15 5,706,228

63 17,269,919

15 5,706,228

(23.81%) (33.04%) (23.81%) (33.04%)

Surface Water 335 124,711,765

154 55,788,062

335 124,711,765

154 55,788,062

(45.97%) (44.73%) (45.97%) (44.73%)

All Very Large 

Systems 398 141,981,684

169 61,494,290

398 141,981,684

169 61,494,290

(42.46%) (43.31%) (42.46%) (43.31%)
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

54

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections

Systems Population Systems Population Systems Population Systems Population

All Systems

All Water 

Systems 1,198 157,219,620

324 65,311,764

64,954 272,002,430

4,369 87,861,589

(27.05%) (41.54%) (6.73%) (32.3%)

1 National estimates for the small and large systems are extrapolations generated by multiplying the UCMR 2 national statistical 

sample findings of system/population percentages by the national system/population inventory numbers for PWSs developed from 

EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems are based directly on the UCMR 2 results, 

since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey. See Section 4.3.3 for a full 

description of national extrapolations. Due to rounding, some calculations may appear to be incorrect.

NDMA was evaluated relative to an HRL of 0.0006 μg/L. Exhibit 5-23 and Exhibit 5-24

present the number of systems and the population they serve with detections greater than onehalf the HRL and the HRL, respectively. Nationally, NDMA is estimated to exceed one-half the 

HRL and the HRL in 3,601 small systems serving an estimated 5.3 million people and 598 large 

systems serving an estimated 21.1 million people. NDMA also exceeded one-half the HRL and 

the HRL in 169 very large systems serving approximately 61.5 million people. These findings 

suggest that an estimated 4,369 PWSs serving approximately 87.9 million people nationally have 

NDMA detections. (Note that since all of the NDMA detections are greater than the HRL of 

0.0006 μg/L, the estimates of national exceedance of one-half the HRL and the HRL are 

identical to the estimated NDMA national occurrence presented in Exhibit 5-22 above.)

Exhibit 5-23: NDMA National Occurrence Measures from UCMR 2 Screening 

Survey Data - Summary of System and Population Served Data - Detections > 1⁄2 

HRL

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections > 1/2 HRL 

(0.0003 μg/L) in the 

UCMR 2 Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections > 1/2 HRL 

(0.0003 μg/L)

Systems Population Systems Population Systems Population Systems Population

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364

10 26,059

57,818 37,685,557

2,409 1,790,869

(4.17%) (4.75%) (4.17%) (4.75%)

Surface Water 240 660,557

74 259,285

3,866 8,928,745

1,192 3,504,746

(30.83%) (39.25%) (30.83%) (39.25%)

All Small 

Systems 480 1,208,921

84 285,344

61,684 46,614,302

3,601 5,295,615

(17.5%) (23.6%) (5.84%) (11.36%)

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184

13 739,206

1,506 38,870,272

130 4,363,960

(8.61%) (11.23%) (8.61%) (11.23%)
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

55

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections > 1/2 HRL 

(0.0003 μg/L) in the 

UCMR 2 Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections > 1/2 HRL 

(0.0003 μg/L)

Systems Population Systems Population Systems Population Systems Population

Surface Water 169 7,444,830

58 2,792,925

1,366 44,536,172

469 16,707,724

(34.32%) (37.51%) (34.32%) (37.51%)

All Large 

Systems 320 14,029,015

71 3,532,130

2,872 83,406,444

598 21,071,684

(22.19%) (25.18%) (20.84%) (25.26%)

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919

15 5,706,228

63 17,269,919

15 5,706,228

(23.81%) (33.04%) (23.81%) (33.04%)

Surface Water 335 124,711,765

154 55,788,062

335 124,711,765

154 55,788,062

(45.97%) (44.73%) (45.97%) (44.73%)

All Very Large 

Systems 398 141,981,684

169 61,494,290

398 141,981,684

169 61,494,290

(42.46%) (43.31%) (42.46%) (43.31%)

All Systems

All Water 

Systems 1,198 157,219,620

324 65,311,764

64,954 272,002,430

4,369 87,861,589

(27.05%) (41.54%) (6.73%) (32.3%)

1 National estimates for the small and large systems are extrapolations generated by multiplying the UCMR 2 national statistical 

sample findings of system/population percentages by the national system/population inventory numbers for PWSs developed from 

EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems are based directly on the UCMR 2 results, 

since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey. See Section 4.3.3 for a full 

description of national extrapolations. Due to rounding, some calculations may appear to be incorrect.

Exhibit 5-24: NDMA National Occurrence Measures from UCMR 2 Screening 

Survey Data - Summary of System and Population Served Data - Detections > 

HRL

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections > HRL 

(0.0006 μg/L) in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections 

> HRL (0.0006 μg/L)

Systems Population Systems Population Systems Population Systems Population

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364

10 26,059

57,818 37,685,557

2,409 1,790,869

(4.17%) (4.75%) (4.17%) (4.75%)

Surface Water 240 660,557

74 259,285

3,866 8,928,745

1,192 3,504,746

(30.83%) (39.25%) (30.83%) (39.25%)

All Small 

Systems 480 1,208,921

84 285,344

61,684 46,614,302

3,601 5,295,615

(17.5%) (23.6%) (5.84%) (11.36%)

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184

13 739,206

1,506 38,870,272

130 4,363,960

(8.61%) (11.23%) (8.61%) (11.23%)
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

56

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections > HRL 

(0.0006 μg/L) in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections 

> HRL (0.0006 μg/L)

Systems Population Systems Population Systems Population Systems Population

Surface Water 169 7,444,830

58 2,792,925

1,366 44,536,172

469 16,707,724

(34.32%) (37.51%) (34.32%) (37.51%)

All Large 

Systems 320 14,029,015

71 3,532,130

2,872 83,406,444

598 21,071,684

(22.19%) (25.18%) (20.84%) (25.26%)

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919

15 5,706,228

63 17,269,919

15 5,706,228

(23.81%) (33.04%) (23.81%) (33.04%)

Surface Water 335 124,711,765

154 55,788,062

335 124,711,765

154 55,788,062

(45.97%) (44.73%) (45.97%) (44.73%)

All Very Large 

Systems 398 141,981,684

169 61,494,290

398 141,981,684

169 61,494,290

(42.46%) (43.31%) (42.46%) (43.31%)

All Systems

All Water 

Systems 1,198 157,219,620

324 65,311,764

64,954 272,002,430

4,369 87,861,589

(27.05%) (41.54%) (6.73%) (32.3%)

1 National estimates for the small and large systems are extrapolations generated by multiplying the UCMR 2 national statistical 

sample findings of system/population percentages by the national system/population inventory numbers for PWSs developed from 

EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems are based directly on the UCMR 2 results, 

since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey. See Section 4.3.3 for a full 

description of national extrapolations. Due to rounding, some calculations may appear to be incorrect.

5.2.9 NMEA

Under the UCMR 2 Screening Survey, 18,101 samples of NMEA were collected from 

1,198 PWSs. Of these, 3 samples (0.02%) had analytical detections of NMEA at or above the 

MRL of 0.003 μg/L. The maximum detected concentration of NMEA was 0.0049 μg/L and the 

median value was also 0.0045 μg/L. Appendix C includes more detailed occurrence numbers for 

NMEA, such as summary statistics by source water type and system size and the number and 

percentage of samples relative to the HRL.

All three NMEA detections occurred in three small surface water systems in two states 

(Oklahoma and Washington). These systems served a cumulative population of 4,480 people or 

0.003% of the total population served by UCMR 2 Screening Survey PWSs. The percentage of 

all small, large, and very large UCMR 2 Screening Survey systems with at least one detection of 

NMEA was 0.25%. A summary of the number of systems with detections and the population 

served by them are presented in Exhibit 5-25.

The design of the UCMR 2 Screening Survey enables extrapolation of national estimates 

of occurrence of contaminants detected in small and large water systems (see Section 4.3.3). 

Occurrence results from the very large systems are already nationally representative so national 

extrapolations are not necessary.
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

57

NMEA is estimated to occur nationally in 48 small water systems serving approximately 

61,000 people. It is not estimated to occur nationally in any large or very large water systems. 

These findings suggest that an estimated 48 PWSs serving approximately 61,000 people 

nationally have NMEA detections.

Exhibit 5-25: NMEA National Occurrence Measures from UCMR 2 Screening 

Survey Data - Summary of System and Population Served Data - All Detections

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections

Systems Population Systems Population Systems Population Systems Population

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364

0 0

57,818 37,685,557

0 0

(0%) (0%) (0%) (0%)

Surface Water 240 660,557

3 4,480

3,866 8,928,745

48 60,556

(1.25%) (0.68%) (1.25%) (0.68%)

All Small 

Systems 480 1,208,921

3 4,480

61,684 46,614,302

48 60,556

(0.63%) (0.37%) (0.08%) (0.13%)

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184

0 0

1,506 38,870,272

0 0

(0%) (0%) (0%) (0%)

Surface Water 169 7,444,830

0 0

1,366 44,536,172

0 0

(0%) (0%) (0%) (0%)

All Large 

Systems 320 14,029,015

0 0

2,872 83,406,444

0 0

(0%) (0%) (0%) (0%)

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919

0 0

63 17,269,919

0 0

(0%) (0%) (0%) (0%)

Surface Water 335 124,711,765

0 0

335 124,711,765

0 0

(0%) (0%) (0%) (0%)

All Very Large 

Systems 398 141,981,684

0 0

398 141,981,684

0 0

(0%) (0%) (0%) (0%)

All Systems

All Water 

Systems 1,198 157,219,620

3 4,480

64,954 272,002,430

48 60,556

(0.25%) (0.003%) (0.07%) (0.02%)

1 National estimates for the small and large systems are extrapolations generated by multiplying the UCMR 2 national statistical 

sample findings of system/population percentages by the national system/population inventory numbers for PWSs developed from 

EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems are based directly on the UCMR 2 results, 

since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey. See Section 4.3.3 for a full 

description of national extrapolations. Due to rounding, some calculations may appear to be incorrect.
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

58

NMEA was evaluated relative to an HRL of 0.003 μg/L. Exhibit 5-26 and Exhibit 5-27

present the number of systems and the population they serve with detections greater than onehalf the HRL and the HRL, respectively. Nationally, NMEA is estimated to exceed one-half the 

HRL and the HRL in 48 small systems serving an estimated 61,000 people. NMEA is not 

estimated to occur nationally in any large or very large water systems. These findings suggest 

that an estimated 48 PWSs serving approximately 61,000 people nationally have NMEA 

detections. (Note that since all of the NMEA detections are greater than the HRL of 0.003 μg/L, 

the estimates of national exceedance of one-half the HRL and the HRL are identical to the 

estimated NMEA national occurrence presented in Exhibit 5-25 above.)

Exhibit 5-26: NMEA National Occurrence Measures from UCMR 2 Screening 

Survey Data - Summary of System and Population Served Data –

Detections > 1⁄2 HRL

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections > 1/2 HRL 

(0.0015 μg/L) in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections 

> 1/2 HRL (0.0015 μg/L)

Systems Population Systems Population Systems Population Systems Population

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364

0 0

57,818 37,685,557

0 0

(0%) (0%) (0%) (0%)

Surface Water 240 660,557

3 4,480

3,866 8,928,745

48 60,556

(1.25%) (0.68%) (1.25%) (0.68%)

All Small 

Systems 480 1,208,921

3 4,480

61,684 46,614,302

48 60,556

(0.63%) (0.37%) (0.08%) (0.13%)

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184

0 0

1,506 38,870,272

0 0

(0%) (0%) (0%) (0%)

Surface Water 169 7,444,830

0 0

1,366 44,536,172

0 0

(0%) (0%) (0%) (0%)

All Large 

Systems 320 14,029,015

0 0

2,872 83,406,444

0 0

(0%) (0%) (0%) (0%)

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919

0 0

63 17,269,919

0 0

(0%) (0%) (0%) (0%)

Surface Water 335 124,711,765

0 0

335 124,711,765

0 0

(0%) (0%) (0%) (0%)

All Very Large 

Systems 398 141,981,684

0 0

398 141,981,684

0 0

(0%) (0%) (0%) (0%)

All Systems

All Water 

Systems 1,198 157,219,620

3 4,480

64,954 272,002,430

48 60,556

(0.25%) (0.003%) (0.07%) (0.02%)

1 National estimates for the small and large systems are extrapolations generated by multiplying the UCMR 2 national statistical 

sample findings of system/population percentages by the national system/population inventory numbers for PWSs developed from 

EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems are based directly on the UCMR 2 results, 
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

59

since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey. See Section 4.3.3 for a full 

description of national extrapolations. Due to rounding, some calculations may appear to be incorrect.

Exhibit 5-27: NMEA National Occurrence Measures from UCMR 2 Screening 

Survey Data - Summary of System and Population Served Data - Detections > 

HRL

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections > HRL 

(0.003 μg/L) in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections 

> HRL (0.003 μg/L)

Systems Population Systems Population Systems Population Systems Population

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364

0 0

57,818 37,685,557

0 0

(0%) (0%) (0%) (0%)

Surface Water 240 660,557

3 4,480

3,866 8,928,745

48 60,556

(1.25%) (0.68%) (1.25%) (0.68%)

All Small 

Systems 480 1,208,921

3 4,480

61,684 46,614,302

48 60,556

(0.63%) (0.37%) (0.08%) (0.13%)

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184

0 0

1,506 38,870,272

0 0

(0%) (0%) (0%) (0%)

Surface Water 169 7,444,830

0 0

1,366 44,536,172

0 0

(0%) (0%) (0%) (0%)

All Large 

Systems 320 14,029,015

0 0

2,872 83,406,444

0 0

(0%) (0%) (0%) (0%)

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919

0 0

63 17,269,919

0 0

(0%) (0%) (0%) (0%)

Surface Water 335 124,711,765

0 0

335 124,711,765

0 0

(0%) (0%) (0%) (0%)

All Very Large 

Systems 398 141,981,684

0 0

398 141,981,684

0 0

(0%) (0%) (0%) (0%)

All Systems

All Water 

Systems 1,198 157,219,620

3 4,480

64,954 272,002,430

48 60,556

(0.25%) (0.003%) (0.07%) (0.02%)

1 National estimates for the small and large systems are extrapolations generated by multiplying the UCMR 2 national statistical 

sample findings of system/population percentages by the national system/population inventory numbers for PWSs developed from 

EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems are based directly on the UCMR 2 results, 

since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey. See Section 4.3.3 for a full 

description of national extrapolations. Due to rounding, some calculations may appear to be incorrect.
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

60

5.2.10 NPYR

Under the UCMR 2 Screening Survey, 18,101 samples of NPYR were collected from 

1,198 PWSs. Of these, 41 samples (0.23%) had analytical detections of NPYR at or above the 

MRL of 0.002 μg/L. The maximum detected concentration of NPYR was 0.0238 μg/L and the 

median value was 0.0039 μg/L. Appendix C includes more detailed occurrence numbers for 

NPYR, such as summary statistics by source water type and system size and the number and 

percentage of samples relative to the HRL.

The 41 NPYR detections occurred in 21 systems in 10 states; all but one of the systems 

were surface water systems. The 21 systems served a cumulative population of approximately 

7.4 million people, or 4.73% of the total population served by UCMR 2 Screening Survey PWSs. 

The percentage of all small, large, and very large UCMR 2 Screening Survey systems with at 

least one detection of NPYR was 1.75%. A summary of the number of systems with detections 

and the population served by them are presented in Exhibit 5-28.

The design of the UCMR 2 Screening Survey enables extrapolation of national estimates 

of occurrence of contaminants detected in small and large water systems (see Section 4.3.3). 

Occurrence results from the very large systems are already nationally representative so national 

extrapolations are not necessary.

NPYR is estimated to occur nationally in 48 small systems serving approximately 

197,000 people. It is also estimated to occur nationally in 48 large systems serving an estimated 

1.1 million people. NPYR also occurred in 12 very large systems serving about 7.2 million 

people. These findings suggest that an estimated 109 PWSs serving approximately 8.6 million 

people nationally have NPYR detections.

Exhibit 5-28: NPYR National Occurrence Measures from UCMR 2 Screening 

Survey Data - Summary of System and Population Served Data - All Detections

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections

Systems Population Systems Population Systems Population Systems Population

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364

0 0

57,818 37,685,557

0 0

(0%) (0%) (0%) (0%)

Surface Water 240 660,557

3 14,572

3,866 8,928,745

48 196,970

(1.25%) (2.21%) (1.25%) (2.21%)

All Small 

Systems 480 1,208,921

3 14,572

61,684 46,614,302

48 196,970

(0.63%) (1.21%) (0.08%) (0.42%)

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184

0 0

1,506 38,870,272

0 0

(0%) (0%) (0%) (0%)
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

61

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections

Systems Population Systems Population Systems Population Systems Population

Surface Water 169 7,444,830

6 188,603

1,366 44,536,172

48 1,128,251

(3.55%) (2.53%) (3.55%) (2.53%)

All Large 

Systems 320 14,029,015

6 188,603

2,872 83,406,444

48 1,128,251

(1.88%) (1.34%) (1.69%) (1.35%)

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919

1 148,137

63 17,269,919

1 148,137

(1.59%) (0.86%) (1.59%) (0.86%)

Surface Water 335 124,711,765

11 7,080,239

335 124,711,765

11 7,080,239

(3.28%) (5.68%) (3.28%) (5.68%)

All Very Large 

Systems 398 141,981,684

12 7,228,376

398 141,981,684

12 7,228,376

(3.02%) (5.09%) (3.02%) (5.09%)

All Systems

All Water 

Systems 1,198 157,219,620

21 7,431,551

64,954 272,002,430

109 8,553,597

(1.75%) (4.73%) (0.17%) (3.14%)

1 National estimates for the small and large systems are extrapolations generated by multiplying the UCMR 2 national statistical 

sample findings of system/population percentages by the national system/population inventory numbers for PWSs developed from 

EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems are based directly on the UCMR 2 results, 

since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey. See Section 4.3.3 for a full 

description of national extrapolations. Due to rounding, some calculations may appear to be incorrect.

NPYR was evaluated relative to an HRL of 0.002 μg/L. Exhibit 5-29 and Exhibit 5-30

present the number of systems with detections greater than one-half the HRL and the HRL, 

respectively as well as the population they serve. NPYR is estimated to occur greater than onehalf the HRL and the HRL in 48 small systems serving approximately 197,000 people nationally. 

It is also estimated to occur nationally greater than one-half the HRL and the HRL in 48 large 

systems serving an estimated 1.1 million people. NPYR also occurred in 12 very large systems 

serving about 7.2 million people. These findings suggest that an estimated 109 PWSs serving 

approximately 8.6 million people nationally have NPYR detections greater than the HRL. (Note 

that since all of the NPYR detections are greater than the HRL of 0.002 μg/L, the estimates of 

national exceedance of one-half the HRL and the HRL are identical to the estimated NPYR 

national occurrence presented in Exhibit 6-27 above.)
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

62

Exhibit 5-29: NPYR National Occurrence Measures from UCMR 2 Screening 

Survey Data - Summary of System and Population Served Data - Detections > 1⁄2 

HRL

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections > 1/2 HRL 

(0.001 μg/L) in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections 

> 1/2 HRL (0.001 μg/L)

Systems Population Systems Population Systems Population Systems Population

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364

0 0

57,818 37,685,557

0 0

(0%) (0%) (0%) (0%)

Surface Water 240 660,557

3 14,572

3,866 8,928,745

48 196,970

(1.25%) (2.21%) (1.25%) (2.21%)

All Small 

Systems 480 1,208,921

3 14,572

61,684 46,614,302

48 196,970

(0.63%) (1.21%) (0.08%) (0.42%)

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184

0 0

1,506 38,870,272

0 0

(0%) (0%) (0%) (0%)

Surface Water 169 7,444,830

6 188,603

1,366 44,536,172

48 1,128,251

(3.55%) (2.53%) (3.55%) (2.53%)

All Large 

Systems 320 14,029,015

6 188,603

2,872 83,406,444

48 1,128,251

(1.88%) (1.34%) (1.69%) (1.35%)

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919

1 148,137

63 17,269,919

1 148,137

(1.59%) (0.86%) (1.59%) (0.86%)

Surface Water 335 124,711,765

11 7,080,239

335 124,711,765

11 7,080,239

(3.28%) (5.68%) (3.28%) (5.68%)

All Very Large 

Systems 398 141,981,684

12 7,228,376

398 141,981,684

12 7,228,376

(3.02%) (5.09%) (3.02%) (5.09%)

All Systems

All Water 

Systems 1,198 157,219,620

21 7,431,551

64,954 272,002,430

109 8,553,597

(1.75%) (4.73%) (0.17%) (3.14%)

1 National estimates for the small and large systems are extrapolations generated by multiplying the UCMR 2 national statistical 

sample findings of system/population percentages by the national system/population inventory numbers for PWSs developed from 

EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems are based directly on the UCMR 2 results, 

since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey. See Section 4.3.3 for a full 

description of national extrapolations. Due to rounding, some calculations may appear to be incorrect.
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

63

Exhibit 5-30: NPYR National Occurrence Measures from UCMR 2 Screening 

Survey Data - Summary of System and Population Served Data - Detections > 

HRL

Source Water 

Type

UCMR 2 Sample

Number (and Percent) 

of Detections > HRL 

(0.002 μg/L) in the 

UCMR 2 Sample

National Inventory

National Estimate1 of 

the Number (and 

Percent) of Detections 

> HRL (0.002 μg/L)

Systems Population Systems Population Systems Population Systems Population

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364

0 0

57,818 37,685,557

0 0

(0%) (0%) (0%) (0%)

Surface Water 240 660,557

3 14,572

3,866 8,928,745

48 196,970

(1.25%) (2.21%) (1.25%) (2.21%)

All Small 

Systems 480 1,208,921

3 14,572

61,684 46,614,302

48 196,970

(0.63%) (1.21%) (0.08%) (0.42%)

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184

0 0

1,506 38,870,272

0 0

(0%) (0%) (0%) (0%)

Surface Water 169 7,444,830

6 188,603

1,366 44,536,172

48 1,128,251

(3.55%) (2.53%) (3.55%) (2.53%)

All Large 

Systems 320 14,029,015

6 188,603

2,872 83,406,444

48 1,128,251

(1.88%) (1.34%) (1.69%) (1.35%)

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919

1 148,137

63 17,269,919

1 148,137

(1.59%) (0.86%) (1.59%) (0.86%)

Surface Water 335 124,711,765

11 7,080,239

335 124,711,765

11 7,080,239

(3.28%) (5.68%) (3.28%) (5.68%)

All Very Large 

Systems 398 141,981,684

12 7,228,376

398 141,981,684

12 7,228,376

(3.02%) (5.09%) (3.02%) (5.09%)

All Systems

All Water 

Systems 1,198 157,219,620

21 7,431,551

64,954 272,002,430

109 8,553,597

(1.75%) (4.73%) (0.17%) (3.14%)

1 National estimates for the small and large systems are extrapolations generated by multiplying the UCMR 2 national statistical 

sample findings of system/population percentages by the national system/population inventory numbers for PWSs developed from 

EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems are based directly on the UCMR 2 results, 

since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey. See Section 4.3.3 for a full 

description of national extrapolations. Due to rounding, some calculations may appear to be incorrect.
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

64

6 References

United States Environmental Protection Agency (USEPA). 1999. Revisions to the Unregulated 

Contaminant Monitoring Regulation for Public Water Systems. Federal Register. Vol. 64, no. 

180, p. 50556, September 17, 1999.

USEPA. 2001. Statistical Design and Sample Selection for the Unregulated Contaminant 

Monitoring Regulation (1999). August 2001. EPA-815-R-01-004, Office of Water.

USEPA. 2002. Analysis of National Occurrence of the 1998 Contaminant Candidate List (CCL) 

Regulatory Determination Priority Contaminants in Public Water Systems. May 2002. EPA-815-

D-01-002, Office of Water.

USEPA. 2003a. Occurrence Estimation Methodology and Occurrence Findings for Six-Year 

Review of National Primary Drinking Water Regulations. June 2003. EPA-815-R-03-006, Office 

of Water.

USEPA. 2003b. Quality Assurance Project Plan for the Implementation of the Unregulated 

Contaminant Monitoring Regulation. Draft. April 2003. Office of Water.

USEPA. 2005. Unregulated Contaminant Monitoring Regulation (UCMR) for Public Water 

Systems Revisions; Proposed Rule. Federal Register. Vol. 70, no. 161, p. 49093, August 22, 

2005.

USEPA. 2006. Reference Guide for the Second Cycle of the Unregulated Contaminant 

Monitoring Regulation (UCMR 2). December 2006. EPA-815-R-06-016, Office of Water.

USEPA. 2007. Unregulated Contaminant Monitoring Regulation (UCMR) for Public Water 

Systems Revisions; Final Rule. Federal Register. Vol. 72, no. 2, p. 367, January 4, 2007.

USEPA. 2008a. The Analysis of Occurrence Data from the Unregulated Contaminant 

Monitoring Program (UCM) and National Inorganics and Radionuclides Survey (NIRS) in 

Support of Regulatory Determinations for the Second Drinking Water Contaminant Candidate 

List (CCL 2). June 2008. EPA-815-R-08-014, Office of Water. 

USEPA. 2008b. The Analysis of Occurrence Data from the First Unregulated Contaminant 

Monitoring Regulation (UCMR 1) in Support of Regulatory Determinations for the Second 

Drinking Water Contaminant Candidate List. June 2008. EPA-815-R-08-013, Office of Water. 

USEPA. 2009. Standard Operating Procedure: NCOD Data Import for Small Systems for the 

Second Cycle of the Unregulated Contaminant Monitoring Regulation. Revision 1.0. December 

2009. SOP TSC UCMR2 004. 

USEPA. 2010. Technical Description of the Statistical Model of Perchlorate Occurrence in 

Drinking Water. Peer Reviewed Draft Report.

USEPA. 2014a. Regulatory Determination 3 Support Document. EPA-815-R-XX-XXX.
EPA-OGWDW Occurrence Data from the UCMR 2 – DRAFT April 2014

65

USEPA. 2014b. Protocol for the Regulatory Determination 3. Post-expert review final. 

Including Appendices A-F. February 2012. EPA-815-R-XX-XXX.
EPA-OGWDW Occurrence Data from the UCMR 2 - DRAFT April 2014

List of Appendix Tables

Appendix A. Final UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and 

Population Served

Appendix B. Final UCMR 2 Data: Summary of Systems and Population Served by State

Appendix C. Final UCMR 2 Data: Summary of Samples (Relative to the HRL) and Summary of 

Detected Concentrations

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, 

and Population Served
EPA-OGWDW Occurrence Data from the UCMR 2 - DRAFT April 2014

Appendix A

Table A1. BDE-47 – Final UCMR 2 Assessment Monitoring Data - Occurrence Based on 

Samples, Systems, and Population Served

Table A2. BDE-99 - Final UCMR 2 Assessment Monitoring Data - Occurrence Based on 

Samples, Systems, and Population Served

Table A3. BDE-100 - Final UCMR 2 Assessment Monitoring Data - Occurrence Based on 

Samples, Systems, and Population Served

Table A4. BDE-153 - Final UCMR 2 Assessment Monitoring Data - Occurrence Based on 

Samples, Systems, and Population Served

Table A5. Dimethoate - Final UCMR 2 Assessment Monitoring Data - Occurrence Based on 

Samples, Systems, and Population Served

Table A6. 1,3-Dinitrobenzene - Final UCMR 2 Assessment Monitoring Data - Occurrence Based 

on Samples, Systems, and Population Served

Table A7. HBB - Final UCMR 2 Assessment Monitoring Data - Occurrence Based on Samples, 

Systems, and Population Served

Table A8. RDX - Final UCMR 2 Assessment Monitoring Data - Occurrence Based on Samples, 

Systems, and Population Served

Table A9. Terbufos Sulfone - Final UCMR 2 Assessment Monitoring Data - Occurrence Based 

on Samples, Systems, and Population Served

Table A10. TNT - Final UCMR 2 Assessment Monitoring Data - Occurrence Based on Samples, 

Systems, and Population Served

Table A11. Acetochlor - Final UCMR 2 Screening Survey Data - Occurrence Based on Samples, 

Systems, and Population Served

Table A12. Acetochlor ESA - Final UCMR 2 Screening Survey Data - Occurrence Based on 

Samples, Systems, and Population Served

Table A13. Acetochlor OA - Final UCMR 2 Screening Survey Data - Occurrence Based on 

Samples, Systems, and Population Served

Table A14. Alachlor - Final UCMR 2 Screening Survey Data - Occurrence Based on Samples, 

Systems, and Population Served

Table A15. Alachlor ESA - Final UCMR 2 Screening Survey Data - Occurrence Based on 

Samples, Systems, and Population Served

Table A16. Alachlor OA - Final UCMR 2 Screening Survey Data - Occurrence Based on 

Samples, Systems, and Population Served

Table A17. Metolachlor - Final UCMR 2 Screening Survey Data - Occurrence Based on 

Samples, Systems, and Population Served

Table A18. Metolachlor ESA - Final UCMR 2 Screening Survey Data - Occurrence Based on 

Samples, Systems, and Population Served
EPA-OGWDW Occurrence Data from the UCMR 2 - DRAFT April 2014

Table A19. Metolachlor OA - Final UCMR 2 Screening Survey Data - Occurrence Based on 

Samples, Systems, and Population Served

Table A20. NDBA - Final UCMR 2 Screening Survey Data - Occurrence Based on Samples, 

Systems, and Population Served

Table A21. NDEA - Final UCMR 2 Screening Survey Data - Occurrence Based on Samples, 

Systems, and Population Served

Table A22. NDMA - Final UCMR 2 Screening Survey Data - Occurrence Based on Samples, 

Systems, and Population Served

Table A23. NDPA - Final UCMR 2 Screening Survey Data - Occurrence Based on Samples, 

Systems, and Population Served

Table A24. NMEA - Final UCMR 2 Screening Survey Data - Occurrence Based on Samples, 

Systems, and Population Served

Table A25. NPYR - Final UCMR 2 Screening Survey Data - Occurrence Based on Samples, 

Systems, and Population Served
EPA-OGWDW

Appendix A. Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 1 of 25

Table A1. BDE-47 - UCMR 2 Assessment Monitoring Data - Occurrence Based on Samples, Systems, and Population Served


Number Percent Number Percent Number Percent

Ground Water 2,328 0 0.00% 618 0 0.00% 1,790,743 0 0.00%

Surface Water 920 0 0.00% 182 0 0.00% 878,262 0 0.00%

All Small Systems 3,248 0 0.00% 800 0 0.00% 2,669,004 0 0.00%

Ground Water 11,760 0 0.00% 1,374 0 0.00% 34,828,693 0 0.00%

Surface Water 10,331 0 0.00% 1,568 0 0.00% 49,758,358 0 0.00%

All Large Systems 22,091 0 0.00% 2,942 0 0.00% 84,587,051 0 0.00%

Ground Water 2,014 0 0.00% 63 0 0.00% 17,269,919 0 0.00%

Surface Water 4,796 0 0.00% 335 0 0.00% 124,711,765 0 0.00%

All Very Large Systems 6,810 0 0.00% 398 0 0.00% 141,981,684 0 0.00%

All Water Systems 32,149 0 0.00% 4,140 0 0.00% 229,237,740 0 0.00%

Source Water Type

Population Served by Systems 

with Detections

Sample of Small Systems (serving ≤ 10,000 people)

Census of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)

All Systems

Total Number 

of Samples

Samples with Detections

Total Number 

of Systems

Systems with Detections Population 

Served by 

Systems
EPA-OGWDW

Appendix A. Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 2 of 25

Table A2. BDE-99 - UCMR 2 Assessment Monitoring Data - Occurrence Based on Samples, Systems, and Population Served


Number Percent Number Percent Number Percent

Ground Water 2,328 0 0.00% 618 0 0.00% 1,790,743 0 0.00%

Surface Water 920 0 0.00% 182 0 0.00% 878,262 0 0.00%

All Small Systems 3,248 0 0.00% 800 0 0.00% 2,669,004 0 0.00%

Ground Water 11,760 0 0.00% 1,374 0 0.00% 34,828,693 0 0.00%

Surface Water 10,331 0 0.00% 1,568 0 0.00% 49,758,358 0 0.00%

All Large Systems 22,091 0 0.00% 2,942 0 0.00% 84,587,051 0 0.00%

Ground Water 2,014 0 0.00% 63 0 0.00% 17,269,919 0 0.00%

Surface Water 4,796 0 0.00% 335 0 0.00% 124,711,765 0 0.00%

All Very Large Systems 6,810 0 0.00% 398 0 0.00% 141,981,684 0 0.00%

All Water Systems 32,149 0 0.00% 4,140 0 0.00% 229,237,740 0 0.00%

Source Water Type

Population Served by Systems 

with Detections

Sample of Small Systems (serving ≤ 10,000 people)

Census of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)

All Systems

Total Number 

of Samples

Samples with Detections

Total Number 

of Systems

Systems with Detections Population 

Served by 

Systems
EPA-OGWDW

Appendix A. Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 3 of 25

Table A3. BDE-100 - UCMR 2 Assessment Monitoring Data - Occurrence Based on Samples, Systems, and Population Served


Number Percent Number Percent Number Percent

Ground Water 2,328 0 0.00% 618 0 0.00% 1,790,743 0 0.00%

Surface Water 920 0 0.00% 182 0 0.00% 878,262 0 0.00%

All Small Systems 3,248 0 0.00% 800 0 0.00% 2,669,004 0 0.00%

Ground Water 11,760 0 0.00% 1,374 0 0.00% 34,828,693 0 0.00%

Surface Water 10,331 0 0.00% 1,568 0 0.00% 49,758,358 0 0.00%

All Large Systems 22,091 0 0.00% 2,942 0 0.00% 84,587,051 0 0.00%

Ground Water 2,014 0 0.00% 63 0 0.00% 17,269,919 0 0.00%

Surface Water 4,796 0 0.00% 335 0 0.00% 124,711,765 0 0.00%

All Very Large Systems 6,810 0 0.00% 398 0 0.00% 141,981,684 0 0.00%

All Water Systems 32,149 0 0.00% 4,140 0 0.00% 229,237,740 0 0.00%

Source Water Type

Population Served by Systems 

with Detections

Sample of Small Systems (serving ≤ 10,000 people)

Census of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)

All Systems

Total Number 

of Samples

Samples with Detections

Total Number 

of Systems

Systems with Detections Population 

Served by 

Systems
EPA-OGWDW

Appendix A. Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 4 of 25

Table A4. BDE-153 - UCMR 2 Assessment Monitoring Data - Occurrence Based on Samples, Systems, and Population Served


Number Percent Number Percent Number Percent

Ground Water 2,328 0 0.00% 618 0 0.00% 1,790,743 0 0.00%

Surface Water 920 0 0.00% 182 0 0.00% 878,262 0 0.00%

All Small Systems 3,248 0 0.00% 800 0 0.00% 2,669,004 0 0.00%

Ground Water 11,759 0 0.00% 1,374 0 0.00% 34,828,693 0 0.00%

Surface Water 10,324 0 0.00% 1,568 0 0.00% 49,758,358 0 0.00%

All Large Systems 22,083 0 0.00% 2,942 0 0.00% 84,587,051 0 0.00%

Ground Water 2,014 0 0.00% 63 0 0.00% 17,269,919 0 0.00%

Surface Water 4,794 0 0.00% 335 0 0.00% 124,711,765 0 0.00%

All Very Large Systems 6,808 0 0.00% 398 0 0.00% 141,981,684 0 0.00%

All Water Systems 32,139 0 0.00% 4,140 0 0.00% 229,237,740 0 0.00%

Source Water Type

Population Served by Systems 

with Detections

Sample of Small Systems (serving ≤ 10,000 people)

Census of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)

All Systems

Total Number 

of Samples

Samples with Detections

Total Number 

of Systems

Systems with Detections Population 

Served by 

Systems
EPA-OGWDW

Appendix A. Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 5 of 25

Table A5. Dimethoate - UCMR 2 Assessment Monitoring Data - Occurrence Based on Samples, Systems, and Population Served


Number Percent Number Percent Number Percent

Ground Water 2,328 0 0.00% 618 0 0.00% 1,790,743 0 0.00%

Surface Water 920 0 0.00% 182 0 0.00% 878,262 0 0.00%

All Small Systems 3,248 0 0.00% 800 0 0.00% 2,669,004 0 0.00%

Ground Water 11,760 0 0.00% 1,374 0 0.00% 34,828,693 0 0.00%

Surface Water 10,332 0 0.00% 1,568 0 0.00% 49,758,358 0 0.00%

All Large Systems 22,092 0 0.00% 2,942 0 0.00% 84,587,051 0 0.00%

Ground Water 2,014 0 0.00% 63 0 0.00% 17,269,919 0 0.00%

Surface Water 4,796 0 0.00% 335 0 0.00% 124,711,765 0 0.00%

All Very Large Systems 6,810 0 0.00% 398 0 0.00% 141,981,684 0 0.00%

All Water Systems 32,150 0 0.00% 4,140 0 0.00% 229,237,740 0 0.00%

Source Water Type

Population Served by Systems 

with Detections

Sample of Small Systems (serving ≤ 10,000 people)

Census of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)

All Systems

Total Number 

of Samples

Samples with Detections

Total Number 

of Systems

Systems with Detections Population 

Served by 

Systems
EPA-OGWDW

Appendix A. Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 6 of 25

Table A6. 1,3-Dinitrobenzene - UCMR 2 Assessment Monitoring Data - Occurrence Based on Samples, Systems, and Population Served


Number Percent Number Percent Number Percent

Ground Water 2,332 0 0.00% 618 0 0.00% 1,790,743 0 0.00%

Surface Water 919 0 0.00% 182 0 0.00% 878,262 0 0.00%

All Small Systems 3,251 0 0.00% 800 0 0.00% 2,669,004 0 0.00%

Ground Water 11,761 0 0.00% 1,373 0 0.00% 34,816,693 0 0.00%

Surface Water 10,327 0 0.00% 1,568 0 0.00% 49,758,358 0 0.00%

All Large Systems 22,088 0 0.00% 2,941 0 0.00% 84,575,051 0 0.00%

Ground Water 2,012 0 0.00% 63 0 0.00% 17,269,919 0 0.00%

Surface Water 4,801 0 0.00% 335 0 0.00% 124,711,765 0 0.00%

All Very Large Systems 6,813 0 0.00% 398 0 0.00% 141,981,684 0 0.00%

All Water Systems 32,152 0 0.00% 4,139 0 0.00% 229,225,740 0 0.00%

Source Water Type

Population Served by Systems 

with Detections

Sample of Small Systems (serving ≤ 10,000 people)

Census of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)

All Systems

Total Number 

of Samples

Samples with Detections

Total Number 

of Systems

Systems with Detections Population 

Served by 

Systems
EPA-OGWDW

Appendix A. Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 7 of 25

Table A7. HBB - UCMR 2 Assessment Monitoring Data - Occurrence Based on Samples, Systems, and Population Served


Number Percent Number Percent Number Percent

Ground Water 2,328 0 0.00% 618 0 0.00% 1,790,743 0 0.00%

Surface Water 920 0 0.00% 182 0 0.00% 878,262 0 0.00%

All Small Systems 3,248 0 0.00% 800 0 0.00% 2,669,004 0 0.00%

Ground Water 11,759 0 0.00% 1,374 0 0.00% 34,828,693 0 0.00%

Surface Water 10,328 0 0.00% 1,568 0 0.00% 49,758,358 0 0.00%

All Large Systems 22,087 0 0.00% 2,942 0 0.00% 84,587,051 0 0.00%

Ground Water 2,014 0 0.00% 63 0 0.00% 17,269,919 0 0.00%

Surface Water 4,794 0 0.00% 335 0 0.00% 124,711,765 0 0.00%

All Very Large Systems 6,808 0 0.00% 398 0 0.00% 141,981,684 0 0.00%

All Water Systems 32,143 0 0.00% 4,140 0 0.00% 229,237,740 0 0.00%

Source Water Type

Population Served by Systems 

with Detections

Sample of Small Systems (serving ≤ 10,000 people)

Census of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)

All Systems

Total Number 

of Samples

Samples with Detections

Total Number 

of Systems

Systems with Detections Population 

Served by 

Systems
EPA-OGWDW

Appendix A. Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 8 of 25

Table A8. RDX - UCMR 2 Assessment Monitoring Data - Occurrence Based on Samples, Systems, and Population Served


Number Percent Number Percent Number Percent

Ground Water 2,332 0 0.00% 618 0 0.00% 1,790,743 0 0.00%

Surface Water 919 0 0.00% 182 0 0.00% 878,262 0 0.00%

All Small Systems 3,251 0 0.00% 800 0 0.00% 2,669,004 0 0.00%

Ground Water 11,760 0 0.00% 1,373 0 0.00% 34,816,693 0 0.00%

Surface Water 10,327 4 0.04% 1,568 3 0.19% 49,758,358 96,033 0.19%

All Large Systems 22,087 4 0.02% 2,941 3 0.10% 84,575,051 96,033 0.11%

Ground Water 2,012 0 0.00% 63 0 0.00% 17,269,919 0 0.00%

Surface Water 4,800 0 0.00% 335 0 0.00% 124,711,765 0 0.00%

All Very Large Systems 6,812 0 0.00% 398 0 0.00% 141,981,684 0 0.00%

All Water Systems 32,150 4 0.01% 4,139 3 0.07% 229,225,740 96,033 0.04%

Population 

Served by 

Systems

All Systems

Source Water Type

Population Served by Systems 

with Detections

Sample of Small Systems (serving ≤ 10,000 people)

Census of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)

Total Number 

of Samples

Samples with Detections

Total Number 

of Systems

Systems with Detections
EPA-OGWDW

Appendix A. Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 9 of 25

Table A9. Terbufos Sulfone - UCMR 2 Assessment Monitoring Data - Occurrence Based on Samples, Systems, and Population Served


Number Percent Number Percent Number Percent

Ground Water 2,328 0 0.00% 618 0 0.00% 1,790,743 0 0.00%

Surface Water 920 0 0.00% 182 0 0.00% 878,262 0 0.00%

All Small Systems 3,248 0 0.00% 800 0 0.00% 2,669,004 0 0.00%

Ground Water 11,760 1 0.01% 1,374 1 0.07% 34,828,693 44,600 0.13%

Surface Water 10,331 0 0.00% 1,568 0 0.00% 49,758,358 0 0.00%

All Large Systems 22,091 1 0.005% 2,942 1 0.03% 84,587,051 44,600 0.05%

Ground Water 2,014 0 0.00% 63 0 0.00% 17,269,919 0 0.00%

Surface Water 4,796 0 0.00% 335 0 0.00% 124,711,765 0 0.00%

All Very Large Systems 6,810 0 0.00% 398 0 0.00% 141,981,684 0 0.00%

All Water Systems 32,149 1 0.003% 4,140 1 0.02% 229,237,740 44,600 0.02%

Census of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)

All Systems

Population Served by Systems 

with Detections

Sample of Small Systems (serving ≤ 10,000 people)

Source Water Type Total Number 

of Samples

Samples with Detections

Total Number 

of Systems

Systems with Detections Population 

Served by 

Systems
EPA-OGWDW

Appendix A. Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 10 of 25

Table A10. TNT - UCMR 2 Assessment Monitoring Data - Occurrence Based on Samples, Systems, and Population Served


Number Percent Number Percent Number Percent

Ground Water 2,332 0 0.00% 618 0 0.00% 1,790,743 0 0.00%

Surface Water 919 0 0.00% 182 0 0.00% 878,262 0 0.00%

All Small Systems 3,251 0 0.00% 800 0 0.00% 2,669,004 0 0.00%

Ground Water 11,760 0 0.00% 1,373 0 0.00% 34,816,693 0 0.00%

Surface Water 10,327 0 0.00% 1,568 0 0.00% 49,758,358 0 0.00%

All Large Systems 22,087 0 0.00% 2,941 0 0.00% 84,575,051 0 0.00%

Ground Water 2,012 0 0.00% 63 0 0.00% 17,269,919 0 0.00%

Surface Water 4,801 0 0.00% 335 0 0.00% 124,711,765 0 0.00%

All Very Large Systems 6,813 0 0.00% 398 0 0.00% 141,981,684 0 0.00%

All Water Systems 32,151 0 0.00% 4,139 0 0.00% 229,225,740 0 0.00%

Source Water Type

Population Served by Systems 

with Detections

Sample of Small Systems (serving ≤ 10,000 people)

Census of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)

All Systems

Total Number 

of Samples

Samples with Detections

Total Number 

of Systems

Systems with Detections Population 

Served by 

Systems
EPA-OGWDW

Appendix A. Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 11 of 25

Table A11. Acetochlor - UCMR 2 Screening Survey Data - Occurrence Based on Samples, Systems, and Population Served


Number Percent Number Percent Number Percent

Ground Water 788 0 0.00% 240 0 0.00% 548,364 0 0.00%

Surface Water 1,040 0 0.00% 240 0 0.00% 660,557 0 0.00%

All Small Systems 1,828 0 0.00% 480 0 0.00% 1,208,921 0 0.00%

Ground Water 1,392 0 0.00% 151 0 0.00% 6,584,184 0 0.00%

Surface Water 1,178 0 0.00% 169 0 0.00% 7,444,830 0 0.00%

All Large Systems 2,570 0 0.00% 320 0 0.00% 14,029,015 0 0.00%

Ground Water 2,010 0 0.00% 63 0 0.00% 17,269,919 0 0.00%

Surface Water 4,785 0 0.00% 335 0 0.00% 124,711,765 0 0.00%

All Very Large Systems 6,795 0 0.00% 398 0 0.00% 141,981,684 0 0.00%

All Water Systems 11,193 0 0.00% 1,198 0 0.00% 157,219,620 0 0.00%

Source Water Type

Population Served by Systems 

with Detections

Sample of Small Systems (serving ≤ 10,000 people)

Sample of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)

All Systems

Total Number 

of Samples

Samples with Detections

Total Number 

of Systems

Systems with Detections Population 

Served by 

Systems
EPA-OGWDW

Appendix A. Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 12 of 25

Table A12. Acetochlor ESA - UCMR 2 Screening Survey Data - Occurrence Based on Samples, Systems, and Population Served


Number Percent Number Percent Number Percent

Ground Water 786 0 0.00% 240 0 0.00% 548,364 0 0.00%

Surface Water 1,035 1 0.10% 240 1 0.42% 660,557 3,455 0.52%

All Small Systems 1,821 1 0.05% 480 1 0.21% 1,208,921 3,455 0.29%

Ground Water 1,381 0 0.00% 151 0 0.00% 6,584,184 0 0.00%

Surface Water 1,170 0 0.00% 169 0 0.00% 7,444,830 0 0.00%

All Large Systems 2,551 0 0.00% 320 0 0.00% 14,029,015 0 0.00%

Ground Water 1,999 0 0.00% 63 0 0.00% 17,269,919 0 0.00%

Surface Water 4,786 1 0.02% 335 1 0.30% 124,711,765 3,828,700 3.07%

All Very Large Systems 6,785 1 0.01% 398 1 0.25% 141,981,684 3,828,700 2.70%

All Water Systems 11,157 2 0.02% 1,198 2 0.17% 157,219,620 3,832,155 2.44%

Sample of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)

All Systems

Population Served by Systems 

with Detections

Sample of Small Systems (serving ≤ 10,000 people)

Source Water Type Total Number 

of Samples

Samples with Detections

Total Number 

of Systems

Systems with Detections Population 

Served by 

Systems
EPA-OGWDW

Appendix A. Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 13 of 25

Table A13. Acetochlor OA - UCMR 2 Screening Survey Data - Occurrence Based on Samples, Systems, and Population Served


Number Percent Number Percent Number Percent

Ground Water 786 0 0.00% 240 0 0.00% 548,364 0 0.00%

Surface Water 1,035 0 0.00% 240 0 0.00% 660,557 0 0.00%

All Small Systems 1,821 0 0.00% 480 0 0.00% 1,208,921 0 0.00%

Ground Water 1,381 0 0.00% 151 0 0.00% 6,584,184 0 0.00%

Surface Water 1,170 0 0.00% 169 0 0.00% 7,444,830 0 0.00%

All Large Systems 2,551 0 0.00% 320 0 0.00% 14,029,015 0 0.00%

Ground Water 1,999 0 0.00% 63 0 0.00% 17,269,919 0 0.00%

Surface Water 4,786 0 0.00% 335 0 0.00% 124,711,765 0 0.00%

All Very Large Systems 6,785 0 0.00% 398 0 0.00% 141,981,684 0 0.00%

All Water Systems 11,157 0 0.00% 1,198 0 0.00% 157,219,620 0 0.00%

Source Water Type

Population Served by Systems 

with Detections

Sample of Small Systems (serving ≤ 10,000 people)

Sample of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)

All Systems

Total Number 

of Samples

Samples with Detections

Total Number 

of Systems

Systems with Detections Population 

Served by 

Systems
EPA-OGWDW

Appendix A. Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 14 of 25

Table A14. Alachlor - UCMR 2 Screening Survey Data - Occurrence Based on Samples, Systems, and Population Served


Number Percent Number Percent Number Percent

Ground Water 788 0 0.00% 240 0 0.00% 548,364 0 0.00%

Surface Water 1,040 0 0.00% 240 0 0.00% 660,557 0 0.00%

All Small Systems 1,828 0 0.00% 480 0 0.00% 1,208,921 0 0.00%

Ground Water 1,392 0 0.00% 151 0 0.00% 6,584,184 0 0.00%

Surface Water 1,178 0 0.00% 169 0 0.00% 7,444,830 0 0.00%

All Large Systems 2,570 0 0.00% 320 0 0.00% 14,029,015 0 0.00%

Ground Water 2,010 0 0.00% 63 0 0.00% 17,269,919 0 0.00%

Surface Water 4,785 0 0.00% 335 0 0.00% 124,711,765 0 0.00%

All Very Large Systems 6,795 0 0.00% 398 0 0.00% 141,981,684 0 0.00%

All Water Systems 11,193 0 0.00% 1,198 0 0.00% 157,219,620 0 0.00%

Source Water Type

Population Served by Systems 

with Detections

Sample of Small Systems (serving ≤ 10,000 people)

Sample of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)

All Systems

Total Number 

of Samples

Samples with Detections

Total Number 

of Systems

Systems with Detections Population 

Served by 

Systems
EPA-OGWDW

Appendix A. Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 15 of 25

Table A15. Alachlor ESA - UCMR 2 Screening Survey Data - Occurrence Based on Samples, Systems, and Population Served


Number Percent Number Percent Number Percent

Ground Water 786 0 0.00% 240 0 0.00% 548,364 0 0.00%

Surface Water 1,035 3 0.29% 240 1 0.42% 660,557 7,705 1.17%

All Small Systems 1,821 3 0.16% 480 1 0.21% 1,208,921 7,705 0.64%

Ground Water 1,381 1 0.07% 151 1 0.66% 6,584,184 73,993 1.12%

Surface Water 1,170 0 0.00% 169 0 0.00% 7,444,830 0 0.00%

All Large Systems 2,551 1 0.04% 320 1 0.31% 14,029,015 73,993 0.53%

Ground Water 1,999 0 0.00% 63 0 0.00% 17,269,919 0 0.00%

Surface Water 4,785 1 0.02% 335 1 0.30% 124,711,765 3,828,700 3.07%

All Very Large Systems 6,784 1 0.01% 398 1 0.25% 141,981,684 3,828,700 2.70%

All Water Systems 11,156 5 0.04% 1,198 3 0.25% 157,219,620 3,910,398 2.49%

Sample of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)

All Systems

Population Served by Systems 

with Detections

Sample of Small Systems (serving ≤ 10,000 people)

Source Water Type Total Number 

of Samples

Samples with Detections

Total Number 

of Systems

Systems with Detections Population 

Served by 

Systems
EPA-OGWDW

Appendix A. Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 16 of 25

Table A16. Alachlor OA - UCMR 2 Screening Survey Data - Occurrence Based on Samples, Systems, and Population Served


Number Percent Number Percent Number Percent

Ground Water 786 0 0.00% 240 0 0.00% 548,364 0 0.00%

Surface Water 1,035 0 0.00% 240 0 0.00% 660,557 0 0.00%

All Small Systems 1,821 0 0.00% 480 0 0.00% 1,208,921 0 0.00%

Ground Water 1,381 0 0.00% 151 0 0.00% 6,584,184 0 0.00%

Surface Water 1,170 0 0.00% 169 0 0.00% 7,444,830 0 0.00%

All Large Systems 2,551 0 0.00% 320 0 0.00% 14,029,015 0 0.00%

Ground Water 1,999 0 0.00% 63 0 0.00% 17,269,919 0 0.00%

Surface Water 4,786 0 0.00% 335 0 0.00% 124,711,765 0 0.00%

All Very Large Systems 6,785 0 0.00% 398 0 0.00% 141,981,684 0 0.00%

All Water Systems 11,157 0 0.00% 1,198 0 0.00% 157,219,620 0 0.00%

Source Water Type

Population Served by Systems 

with Detections

Sample of Small Systems (serving ≤ 10,000 people)

Sample of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)

All Systems

Total Number 

of Samples

Samples with Detections

Total Number 

of Systems

Systems with Detections Population 

Served by 

Systems
EPA-OGWDW

Appendix A. Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 17 of 25

Table A17. Metolachlor - UCMR 2 Screening Survey Data - Occurrence Based on Samples, Systems, and Population Served


Number Percent Number Percent Number Percent

Ground Water 788 0 0.00% 240 0 0.00% 548,364 0 0.00%

Surface Water 1,040 2 0.19% 240 2 0.83% 660,557 2,240 0.34%

All Small Systems 1,828 2 0.11% 480 2 0.42% 1,208,921 2,240 0.19%

Ground Water 1,392 0 0.00% 151 0 0.00% 6,584,184 0 0.00%

Surface Water 1,178 0 0.00% 169 0 0.00% 7,444,830 0 0.00%

All Large Systems 2,570 0 0.00% 320 0 0.00% 14,029,015 0 0.00%

Ground Water 2,010 0 0.00% 63 0 0.00% 17,269,919 0 0.00%

Surface Water 4,784 1 0.02% 335 1 0.30% 124,711,765 105,270 0.08%

All Very Large Systems 6,794 1 0.01% 398 1 0.25% 141,981,684 105,270 0.07%

All Water Systems 11,192 3 0.03% 1,198 3 0.25% 157,219,620 107,510 0.07%

Sample of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)

All Systems

Population Served by Systems 

with Detections

Sample of Small Systems (serving ≤ 10,000 people)

Source Water Type Total Number 

of Samples

Samples with Detections

Total Number 

of Systems

Systems with Detections Population 

Served by 

Systems
EPA-OGWDW

Appendix A. Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 18 of 25

Table A18. Metolachlor ESA - UCMR 2 Screening Survey Data - Occurrence Based on Samples, Systems, and Population Served


Number Percent Number Percent Number Percent

Ground Water 786 16 2.04% 240 5 2.08% 548,364 17,540 3.20%

Surface Water 1,035 5 0.48% 240 3 1.25% 660,557 17,498 2.65%

All Small Systems 1,821 21 1.15% 480 8 1.67% 1,208,921 35,038 2.90%

Ground Water 1,381 4 0.29% 151 1 0.66% 6,584,184 73,993 1.12%

Surface Water 1,170 8 0.68% 169 3 1.78% 7,444,830 138,897 1.87%

All Large Systems 2,551 12 0.47% 320 4 1.25% 14,029,015 212,890 1.52%

Ground Water 1,999 9 0.45% 63 1 1.59% 17,269,919 1,045,522 6.05%

Surface Water 4,786 10 0.21% 335 6 1.79% 124,711,765 4,580,535 3.67%

All Very Large Systems 6,785 19 0.28% 398 7 1.76% 141,981,684 5,626,057 3.96%

All Water Systems 11,157 52 0.47% 1,198 19 1.59% 157,219,620 5,873,985 3.74%

Sample of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)

All Systems

Population Served by Systems 

with Detections

Sample of Small Systems (serving ≤ 10,000 people)

Source Water Type Total Number 

of Samples

Samples with Detections

Total Number 

of Systems

Systems with Detections Population 

Served by 

Systems
EPA-OGWDW

Appendix A. Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 19 of 25

Table A19. Metolachlor OA - UCMR 2 Screening Survey Data - Occurrence Based on Samples, Systems, and Population Served


Number Percent Number Percent Number Percent

Ground Water 786 0 0.00% 240 0 0.00% 548,364 0 0.00%

Surface Water 1,035 0 0.00% 240 0 0.00% 660,557 0 0.00%

All Small Systems 1,821 0 0.00% 480 0 0.00% 1,208,921 0 0.00%

Ground Water 1,381 0 0.00% 151 0 0.00% 6,584,184 0 0.00%

Surface Water 1,170 0 0.00% 169 0 0.00% 7,444,830 0 0.00%

All Large Systems 2,551 0 0.00% 320 0 0.00% 14,029,015 0 0.00%

Ground Water 1,999 3 0.15% 63 1 1.59% 17,269,919 1,045,522 6.05%

Surface Water 4,786 0 0.00% 335 0 0.00% 124,711,765 0 0.00%

All Very Large Systems 6,785 3 0.04% 398 1 0.25% 141,981,684 1,045,522 0.74%

All Water Systems 11,157 3 0.03% 1,198 1 0.08% 157,219,620 1,045,522 0.67%

Sample of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)

All Systems

Population Served by Systems 

with Detections

Sample of Small Systems (serving ≤ 10,000 people)

Source Water Type Total Number 

of Samples

Samples with Detections

Total Number 

of Systems

Systems with Detections Population 

Served by 

Systems
EPA-OGWDW

Appendix A. Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 20 of 25

Table A20. NDBA - UCMR 2 Screening Survey Data - Occurrence Based on Samples, Systems, and Population Served


Number Percent Number Percent Number Percent

Ground Water 1,237 3 0.24% 240 2 0.83% 548,364 14,292 2.61%

Surface Water 1,996 0 0.00% 240 0 0.00% 660,557 0 0.00%

All Small Systems 3,233 3 0.09% 480 2 0.42% 1,208,921 14,292 1.18%

Ground Water 1,932 0 0.00% 151 0 0.00% 6,584,184 0 0.00%

Surface Water 2,091 0 0.00% 169 0 0.00% 7,444,830 0 0.00%

All Large Systems 4,023 0 0.00% 320 0 0.00% 14,029,015 0 0.00%

Ground Water 2,966 3 0.10% 63 1 1.59% 17,269,919 1,045,522 6.05%

Surface Water 7,879 3 0.04% 335 2 0.60% 124,711,765 626,169 0.50%

All Very Large Systems 10,845 6 0.06% 398 3 0.75% 141,981,684 1,671,691 1.18%

All Water Systems 18,101 9 0.05% 1,198 5 0.42% 157,219,620 1,685,983 1.07%

Sample of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)

All Systems

Population Served by Systems 

with Detections

Sample of Small Systems (serving ≤ 10,000 people)

Source Water Type Total Number 

of Samples

Samples with Detections

Total Number 

of Systems

Systems with Detections Population 

Served by 

Systems
EPA-OGWDW

Appendix A. Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 21 of 25

Table A21. NDEA - UCMR 2 Screening Survey Data - Occurrence Based on Samples, Systems, and Population Served


Number Percent Number Percent Number Percent

Ground Water 1,237 1 0.08% 240 1 0.42% 548,364 6,575 1.20%

Surface Water 1,996 0 0.00% 240 0 0.00% 660,557 0 0.00%

All Small Systems 3,233 1 0.03% 480 1 0.21% 1,208,921 6,575 0.54%

Ground Water 1,920 3 0.16% 151 1 0.66% 6,584,184 93,660 1.42%

Surface Water 2,091 6 0.29% 169 3 1.78% 7,444,830 148,608 2.00%

All Large Systems 4,011 9 0.22% 320 4 1.25% 14,029,015 242,268 1.73%

Ground Water 2,968 7 0.24% 63 5 7.94% 17,269,919 668,861 3.87%

Surface Water 7,884 29 0.37% 335 16 4.78% 124,711,765 10,314,490 8.27%

All Very Large Systems 10,852 36 0.33% 398 21 5.28% 141,981,684 10,983,351 7.74%

All Water Systems 18,096 46 0.25% 1,198 26 2.17% 157,219,620 11,232,194 7.14%

Sample of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)

All Systems

Population Served by Systems 

with Detections

Sample of Small Systems (serving ≤ 10,000 people)

Source Water Type Total Number 

of Samples

Samples with Detections

Total Number 

of Systems

Systems with Detections Population 

Served by 

Systems
EPA-OGWDW

Appendix A. Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 22 of 25

Table A22. NDMA - UCMR 2 Screening Survey Data - Occurrence Based on Samples, Systems, and Population Served


Number Percent Number Percent Number Percent

Ground Water 1,237 14 1.13% 240 10 4.17% 548,364 26,059 4.75%

Surface Water 1,996 326 16.33% 240 74 30.83% 660,557 259,285 39.25%

All Small Systems 3,233 340 10.52% 480 84 17.50% 1,208,921 285,344 23.60%

Ground Water 1,932 48 2.48% 151 13 8.61% 6,584,184 739,206 11.23%

Surface Water 2,091 305 14.59% 169 58 34.32% 7,444,830 2,792,925 37.51%

All Large Systems 4,023 353 8.77% 320 71 22.19% 14,029,015 3,532,130 25.18%

Ground Water 2,966 52 1.75% 63 15 23.81% 17,269,919 5,706,228 33.04%

Surface Water 7,876 1,116 14.17% 335 154 45.97% 124,711,765 55,788,062 44.73%

All Very Large Systems 10,842 1,168 10.77% 398 169 42.46% 141,981,684 61,494,290 43.31%

All Water Systems 18,098 1,861 10.28% 1,198 324 27.05% 157,219,620 65,311,764 41.54%

Sample of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)

All Systems

Population Served by Systems 

with Detections

Sample of Small Systems (serving ≤ 10,000 people)

Source Water Type Total Number 

of Samples

Samples with Detections

Total Number 

of Systems

Systems with Detections Population 

Served by 

Systems
EPA-OGWDW

Appendix A. Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 23 of 25

Table A23. NDPA - UCMR 2 Screening Survey Data - Occurrence Based on Samples, Systems, and Population Served


Number Percent Number Percent Number Percent

Ground Water 1,237 0 0.00% 240 0 0.00% 548,364 0 0.00%

Surface Water 1,996 0 0.00% 240 0 0.00% 660,557 0 0.00%

All Small Systems 3,233 0 0.00% 480 0 0.00% 1,208,921 0 0.00%

Ground Water 1,932 0 0.00% 151 0 0.00% 6,584,184 0 0.00%

Surface Water 2,091 0 0.00% 169 0 0.00% 7,444,830 0 0.00%

All Large Systems 4,023 0 0.00% 320 0 0.00% 14,029,015 0 0.00%

Ground Water 2,968 0 0.00% 63 0 0.00% 17,269,919 0 0.00%

Surface Water 7,883 0 0.00% 335 0 0.00% 124,711,765 0 0.00%

All Very Large Systems 10,851 0 0.00% 398 0 0.00% 141,981,684 0 0.00%

All Water Systems 18,107 0 0.00% 1,198 0 0.00% 157,219,620 0 0.00%

Source Water Type

Population Served by Systems 

with Detections

Sample of Small Systems (serving ≤ 10,000 people)

Sample of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)

All Systems

Total Number 

of Samples

Samples with Detections

Total Number 

of Systems

Systems with Detections Population 

Served by 

Systems
EPA-OGWDW

Appendix A. Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 24 of 25

Table A24. NMEA - UCMR 2 Screening Survey Data - Occurrence Based on Samples, Systems, and Population Served


Number Percent Number Percent Number Percent

Ground Water 1,237 0 0.00% 240 0 0.00% 548,364 0 0.00%

Surface Water 1,996 3 0.15% 240 3 1.25% 660,557 4,480 0.68%

All Small Systems 3,233 3 0.09% 480 3 0.63% 1,208,921 4,480 0.37%

Ground Water 1,932 0 0.00% 151 0 0.00% 6,584,184 0 0.00%

Surface Water 2,091 0 0.00% 169 0 0.00% 7,444,830 0 0.00%

All Large Systems 4,023 0 0.00% 320 0 0.00% 14,029,015 0 0.00%

Ground Water 2,966 0 0.00% 63 0 0.00% 17,269,919 0 0.00%

Surface Water 7,879 0 0.00% 335 0 0.00% 124,711,765 0 0.00%

All Very Large Systems 10,845 0 0.00% 398 0 0.00% 141,981,684 0 0.00%

All Water Systems 18,101 3 0.02% 1,198 3 0.25% 157,219,620 4,480 0.003%

Sample of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)

All Systems

Population Served by Systems 

with Detections

Sample of Small Systems (serving ≤ 10,000 people)

Source Water Type Total Number 

of Samples

Samples with Detections

Total Number 

of Systems

Systems with Detections Population 

Served by 

Systems
EPA-OGWDW

Appendix A. Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 25 of 25

Table A25. NPYR - UCMR 2 Screening Survey Data - Occurrence Based on Samples, Systems, and Population Served


Number Percent Number Percent Number Percent

Ground Water 1,237 0 0.00% 240 0 0.00% 548,364 0 0.00%

Surface Water 1,996 11 0.55% 240 3 1.25% 660,557 14,572 2.21%

All Small Systems 3,233 11 0.34% 480 3 0.63% 1,208,921 14,572 1.21%

Ground Water 1,932 0 0.00% 151 0 0.00% 6,584,184 0 0.00%

Surface Water 2,091 7 0.33% 169 6 3.55% 7,444,830 188,603 2.53%

All Large Systems 4,023 7 0.17% 320 6 1.88% 14,029,015 188,603 1.34%

Ground Water 2,966 1 0.03% 63 1 1.59% 17,269,919 148,137 0.86%

Surface Water 7,879 22 0.28% 335 11 3.28% 124,711,765 7,080,239 5.68%

All Very Large Systems 10,845 23 0.21% 398 12 3.02% 141,981,684 7,228,376 5.09%

All Water Systems 18,101 41 0.23% 1,198 21 1.75% 157,219,620 7,431,551 4.73%

Sample of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)

All Systems

Population Served by Systems 

with Detections

Sample of Small Systems (serving ≤ 10,000 people)

Source Water Type Total Number 

of Samples

Samples with Detections

Total Number 

of Systems

Systems with Detections Population 

Served by 

Systems
EPA-OGWDW Occurrence Data from the UCMR 2 - DRAFT April 2014

Appendix B

Table B1. BDE-47 - Final UCMR 2 Assessment Monitoring Data - Number of Systems and 

Population Served by State

Table B2. BDE-99 - Final UCMR 2 Assessment Monitoring Data - Number of Systems and 

Population Served by State

Table B3. BDE-100 - Final UCMR 2 Assessment Monitoring Data - Number of Systems and 

Population Served by State

Table B4. BDE-153 - Final UCMR 2 Assessment Monitoring Data - Number of Systems and 

Population Served by State

Table B5. Dimethoate - Final UCMR 2 Assessment Monitoring Data - Number of Systems and 

Population Served by State

Table B6. 1,3-Dinitrobenzene - Final UCMR 2 Assessment Monitoring Data - Number of 

Systems and Population Served by State

Table B7. HBB - Final UCMR 2 Assessment Monitoring Data - Number of Systems and 

Population Served by State

Table B8. RDX - Final UCMR 2 Assessment Monitoring Data - Number of Systems and 

Population Served by State

Table B9. Terbufos Sulfone - Final UCMR 2 Assessment Monitoring Data - Number of 

Systems and Population Served by State

Table B10. TNT - Final UCMR 2 Assessment Monitoring Data - Number of Systems and 

Population Served by State

Table B11. Acetochlor - Final UCMR 2 Screening Survey Data - Number of Systems and 

Population Served by State

Table B12. Acetochlor ESA - Final UCMR 2 Screening Survey Data - Number of Systems and 

Population Served by State

Table B13. Acetochlor OA - Final UCMR 2 Screening Survey Data - Number of Systems and 

Population Served by State

Table B14. Alachlor - Final UCMR 2 Screening Survey Data - Number of Systems and 

Population Served by State

Table B15. Alachlor ESA - Final UCMR 2 Screening Survey Data - Number of Systems and 

Population Served by State

Table B16. Alachlor OA - Final UCMR 2 Screening Survey Data - Number of Systems and 

Population Served by State

Table B17. Metolachlor - Final UCMR 2 Screening Survey Data - Number of Systems and 

Population Served by State

Table B18. Metolachlor ESA - Final UCMR 2 Screening Survey Data - Number of Systems and 

Population Served by State
EPA-OGWDW Occurrence Data from the UCMR 2 - DRAFT April 2014

Table B19. Metolachlor OA - Final UCMR 2 Screening Survey Data - Number of Systems and 

Population Served by State

Table B20. NDBA - Final UCMR 2 Screening Survey Data - Number of Systems and 

Population Served by State

Table B21. NDEA - Final UCMR 2 Screening Survey Data - Number of Systems and 

Population Served by State

Table B22. NDMA - Final UCMR 2 Screening Survey Data - Number of Systems and 

Population Served by State

Table B23. NDPA - Final UCMR 2 Screening Survey Data - Number of Systems and 

Population Served by State

Table B24. NMEA - Final UCMR 2 Screening Survey Data - Number of Systems and 

Population Served by State

Table B25. NPYR - Final UCMR 2 Screening Survey Data - Number of Systems and Population 

Served by State
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 1 of 50

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 946 120 13 3 36 62 0 6

Alaska 49 9 3 2 2 1 0 1

American Samoa 4 1 0 0 0 1 0 0

Arizona 951 69 13 0 41 5 1 9

Arkansas 289 61 9 4 17 28 0 3

California 6,725 393 32 14 123 152 8 64

Colorado 505 68 5 6 13 34 0 10

Connecticut 329 41 5 1 7 23 0 5

Delaware 106 10 4 0 2 1 0 3

District of Columbia 8 1 0 0 0 0 0 1

Florida 1,152 231 28 0 161 7 23 12

Georgia 570 110 14 5 27 51 1 12

Guam 246 3 0 0 0 2 1 0

Hawaii 315 18 3 0 8 5 2 0

Idaho 257 22 7 0 13 1 0 1

Illinois 839 141 22 5 61 42 3 8

Indiana 399 99 16 2 56 18 1 6

Iowa 233 54 14 1 24 12 0 3

Kansas 224 46 7 4 12 17 0 6

Kentucky 433 107 2 4 10 86 1 4

Louisiana 606 92 25 3 36 21 3 4

Maine 89 19 4 2 3 9 0 1

Maryland 180 38 7 2 13 12 1 3

Massachusetts 965 126 9 3 55 50 1 8

Michigan 393 77 21 2 18 29 2 5

Minnesota 356 91 15 1 64 9 0 2

Mississippi 636 78 30 0 46 0 0 2

Missouri 464 75 16 4 31 19 1 4

Montana 112 13 4 2 1 5 0 1

N. Mariana Islands 69 2 1 0 1 0 0 0

Navajo Nation 12 2 1 0 1 0 0 0

Nebraska 238 22 8 0 10 2 0 2

Nevada 184 15 4 1 4 2 0 4

New Hampshire 155 24 5 1 4 13 0 1

New Jersey 1,055 131 14 1 55 49 1 11

New Mexico 331 32 7 1 18 5 1 0

New York 1,542 154 18 11 47 59 5 14

North Carolina 1,032 126 16 5 27 65 1 12

North Dakota 50 12 2 1 3 6 0 0

Ohio 525 153 20 5 59 58 1 10

Oklahoma 422 62 6 8 11 34 0 3

Oregon 365 55 6 4 10 30 0 5

Pennsylvania 1,218 171 24 13 24 92 0 18

Puerto Rico 655 83 6 5 17 47 0 8

Rhode Island 92 13 2 0 4 5 0 2

South Carolina 321 63 6 3 8 41 0 5

South Dakota 87 15 4 1 3 6 0 1

Tennessee 569 121 5 8 16 87 1 4

Texas 2,200 295 63 23 62 122 1 24

Utah 513 54 6 2 14 25 0 7

Vermont 46 11 3 2 0 6 0 0

Virgin Islands 20 4 2 0 0 2 0 0

Virginia 409 73 9 6 4 43 0 11

Washington 834 93 18 3 46 20 2 4

West Virginia 142 36 3 6 3 22 0 2

Wisconsin 561 78 19 1 38 16 1 3

Wyoming 56 11 3 0 1 7 0 0

Tribes - Region 1 4 1 0 0 0 1 0 0

Tribes - Region 5 10 4 3 0 1 0 0 0

Tribes - Region 6 0 0 0 0 0 0 0 0

Tribes - Region 8 6 2 0 1 1 0 0 0

Tribes - Region 9 45 9 6 0 2 1 0 0

Total 32,149 4,140 618 182 1,374 1,568 63 335 1 The UCMR data are not representative at the state-level.

Table B1. BDE-47 - UCMR 2 Assessment Monitoring Data - Number of Systems and Population Served by State

State 1

Total 

Number of 

Samples

Total 

Number of 

Systems

Number of Small Systems 

(serving ≤10,000 people)

Number of Large Systems 

(serving 10,001 - 100,000 people)

Number of Very Large Systems 

(serving >100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 2 of 50

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 4,249,148 64,214 15,859 850,382 1,612,450 0 1,706,245

Alaska 234,237 6,025 9,791 59,290 23,965 0 135,166

American Samoa 45,000 0 0 0 45,000 0 0

Arizona 4,417,574 32,953 0 999,514 110,587 675,445 2,599,075

Arkansas 1,771,814 31,449 19,189 395,797 638,748 0 686,632

California 32,516,672 101,399 70,338 3,738,533 6,626,442 1,088,908 20,891,052

Colorado 4,395,410 12,154 13,190 312,380 1,020,990 0 3,036,696

Connecticut 2,423,307 6,961 7,784 101,145 929,609 0 1,377,809

Delaware 550,332 14,255 0 54,443 36,130 0 445,504

District of Columbia 783,055 0 0 0 0 0 783,055

Florida 15,964,524 85,230 0 5,601,752 190,650 7,266,168 2,820,724

Georgia 6,323,497 30,214 19,473 555,035 1,594,334 163,688 3,960,753

Guam 136,301 0 0 0 36,300 100,001 0

Hawaii 1,168,403 14,938 0 237,807 128,935 786,723 0

Idaho 598,638 20,705 0 377,881 14,052 0 186,000

Illinois 7,910,559 62,240 31,607 1,237,820 1,377,669 405,228 4,795,996

Indiana 3,833,462 53,832 8,150 1,343,907 460,953 113,400 1,853,220

Iowa 1,669,054 34,873 7,782 635,226 435,492 0 555,682

Kansas 1,903,624 14,044 15,781 288,095 327,403 0 1,258,301

Kentucky 4,050,273 6,419 21,540 145,399 2,190,482 85,697 1,600,737

Louisiana 3,411,211 100,823 8,085 762,163 705,285 663,655 1,171,200

Maine 368,811 10,566 8,770 43,690 192,225 0 113,560

Maryland 4,493,237 9,908 6,123 346,418 348,121 249,600 3,533,067

Massachusetts 7,942,671 43,421 14,171 1,317,567 1,768,248 159,180 4,640,084

Michigan 5,866,881 54,175 12,964 366,966 859,317 283,846 4,289,613

Minnesota 3,092,542 38,944 4,960 1,707,947 406,914 0 933,777

Mississippi 1,418,405 86,727 0 988,496 0 0 343,182

Missouri 3,711,957 49,173 19,101 600,252 449,297 223,971 2,370,164

Montana 376,922 8,734 8,778 72,215 183,824 0 103,371

N. Mariana Islands 72,737 1,081 0 71,656 0 0 0

Navajo Nation 19,080 836 0 18,244 0 0 0

Nebraska 998,770 26,423 0 219,594 37,864 0 714,889

Nevada 1,999,825 13,712 8,323 59,000 73,095 0 1,845,695

New Hampshire 562,737 8,516 10,000 86,706 305,451 0 152,064

New Jersey 7,116,424 60,693 3,400 1,156,623 1,666,422 115,378 4,113,907

New Mexico 1,152,067 16,238 8,256 501,653 172,567 453,353 0

New York 14,764,779 35,519 44,587 1,371,569 1,657,155 1,682,822 9,973,127

North Carolina 5,366,551 37,318 18,964 580,495 1,974,056 108,666 2,647,052

North Dakota 350,292 5,414 2,694 78,529 263,655 0 0

Ohio 8,788,460 64,492 31,964 1,498,349 1,822,242 123,850 5,247,564

Oklahoma 2,491,284 10,318 31,117 241,483 950,915 0 1,257,451

Oregon 2,413,155 13,140 24,170 188,470 830,806 0 1,356,569

Pennsylvania 8,692,491 58,224 57,237 425,487 2,978,041 0 5,173,502

Puerto Rico 5,552,363 20,268 20,177 384,807 1,688,215 0 3,438,896

Rhode Island 911,235 1,812 0 107,302 250,585 0 551,536

South Carolina 2,785,309 14,508 19,828 180,888 1,218,197 0 1,351,888

South Dakota 349,953 10,139 1,592 43,056 167,166 0 128,000

Tennessee 4,625,703 22,345 49,153 428,243 2,499,282 687,096 939,584

Texas 18,832,904 189,890 115,111 1,429,442 3,795,822 1,253,442 12,049,197

Utah 2,403,787 20,075 15,000 274,446 934,364 0 1,159,902

Vermont 196,255 5,245 5,830 0 185,180 0 0

Virgin Islands 67,889 2,550 0 0 65,339 0 0

Virginia 4,635,684 11,756 31,277 98,415 1,285,803 0 3,208,433

Washington 4,265,055 47,921 18,679 1,255,343 756,649 374,556 1,811,906

West Virginia 958,526 8,711 26,897 65,669 527,486 0 329,764

Wisconsin 2,806,236 59,710 8,550 842,048 620,506 205,247 1,070,175

Wyoming 296,668 6,591 0 24,999 265,078 0 0

Tribes - Region 1 41,000 0 0 0 41,000 0 0

Tribes - Region 5 18,788 4,068 0 14,720 0 0 0

Tribes - Region 6 0 0 0 0 0 0 0

Tribes - Region 8 12,160 0 2,020 10,140 0 0 0

Tribes - Region 9 62,055 18,855 0 31,200 12,000 0 0

Total 229,237,740 1,790,743 878,262 34,828,693 49,758,358 17,269,919 124,711,765 1 The UCMR data are not representative at the state-level.

Total Population 

Served

Pop. Served by Small Systems 

(serving ≤10,000 people)

Pop. Served by Large Systems 

(serving 10,001 - 100,000 people)

Pop. Served by Very Large Systems 

(serving >100,000 people)

State 1

Table B1. BDE-47 - UCMR 2 Assessment Monitoring Data - Number of Systems and Population Served by State
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 3 of 50

Table B2. BDE-99 - UCMR 2 Assessment Monitoring Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 946 120 13 3 36 62 0 6

Alaska 49 9 3 2 2 1 0 1

American Samoa 4 1 0 0 0 1 0 0

Arizona 951 69 13 0 41 5 1 9

Arkansas 289 61 9 4 17 28 0 3

California 6,725 393 32 14 123 152 8 64

Colorado 505 68 5 6 13 34 0 10

Connecticut 329 41 5 1 7 23 0 5

Delaware 106 10 4 0 2 1 0 3

District of Columbia 8 1 0 0 0 0 0 1

Florida 1,152 231 28 0 161 7 23 12

Georgia 570 110 14 5 27 51 1 12

Guam 246 3 0 0 0 2 1 0

Hawaii 315 18 3 0 8 5 2 0

Idaho 257 22 7 0 13 1 0 1

Illinois 839 141 22 5 61 42 3 8

Indiana 399 99 16 2 56 18 1 6

Iowa 233 54 14 1 24 12 0 3

Kansas 224 46 7 4 12 17 0 6

Kentucky 433 107 2 4 10 86 1 4

Louisiana 606 92 25 3 36 21 3 4

Maine 89 19 4 2 3 9 0 1

Maryland 180 38 7 2 13 12 1 3

Massachusetts 965 126 9 3 55 50 1 8

Michigan 393 77 21 2 18 29 2 5

Minnesota 356 91 15 1 64 9 0 2

Mississippi 636 78 30 0 46 0 0 2

Missouri 464 75 16 4 31 19 1 4

Montana 112 13 4 2 1 5 0 1

N. Mariana Islands 69 2 1 0 1 0 0 0

Navajo Nation 12 2 1 0 1 0 0 0

Nebraska 238 22 8 0 10 2 0 2

Nevada 184 15 4 1 4 2 0 4

New Hampshire 155 24 5 1 4 13 0 1

New Jersey 1,055 131 14 1 55 49 1 11

New Mexico 331 32 7 1 18 5 1 0

New York 1,542 154 18 11 47 59 5 14

North Carolina 1,032 126 16 5 27 65 1 12

North Dakota 50 12 2 1 3 6 0 0

Ohio 525 153 20 5 59 58 1 10

Oklahoma 422 62 6 8 11 34 0 3

Oregon 365 55 6 4 10 30 0 5

Pennsylvania 1,218 171 24 13 24 92 0 18

Puerto Rico 655 83 6 5 17 47 0 8

Rhode Island 92 13 2 0 4 5 0 2

South Carolina 321 63 6 3 8 41 0 5

South Dakota 87 15 4 1 3 6 0 1

Tennessee 569 121 5 8 16 87 1 4

Texas 2,200 295 63 23 62 122 1 24

Utah 513 54 6 2 14 25 0 7

Vermont 46 11 3 2 0 6 0 0

Virgin Islands 20 4 2 0 0 2 0 0

Virginia 409 73 9 6 4 43 0 11

Washington 834 93 18 3 46 20 2 4

West Virginia 142 36 3 6 3 22 0 2

Wisconsin 561 78 19 1 38 16 1 3

Wyoming 56 11 3 0 1 7 0 0

Tribes - Region 1 4 1 0 0 0 1 0 0

Tribes - Region 5 10 4 3 0 1 0 0 0

Tribes - Region 6 0 0 0 0 0 0 0 0

Tribes - Region 8 6 2 0 1 1 0 0 0

Tribes - Region 9 45 9 6 0 2 1 0 0

Total 32,149 4,140 618 182 1,374 1,568 63 335 1

 The UCMR data are not representative at the state-level.

Number of Very Large Systems 

(serving >100,000 people)

State 1

Total 

Number of 

Samples

Total 

Number of 

Systems

Number of Small Systems 

(serving ≤10,000 people)

Number of Large Systems 

(serving 10,001 - 100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 4 of 50

Table B2. BDE-99 - UCMR 2 Assessment Monitoring Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 4,249,148 64,214 15,859 850,382 1,612,450 0 1,706,245

Alaska 234,237 6,025 9,791 59,290 23,965 0 135,166

American Samoa 45,000 0 0 0 45,000 0 0

Arizona 4,417,574 32,953 0 999,514 110,587 675,445 2,599,075

Arkansas 1,771,814 31,449 19,189 395,797 638,748 0 686,632

California 32,516,672 101,399 70,338 3,738,533 6,626,442 1,088,908 20,891,052

Colorado 4,395,410 12,154 13,190 312,380 1,020,990 0 3,036,696

Connecticut 2,423,307 6,961 7,784 101,145 929,609 0 1,377,809

Delaware 550,332 14,255 0 54,443 36,130 0 445,504

District of Columbia 783,055 0 0 0 0 0 783,055

Florida 15,964,524 85,230 0 5,601,752 190,650 7,266,168 2,820,724

Georgia 6,323,497 30,214 19,473 555,035 1,594,334 163,688 3,960,753

Guam 136,301 0 0 0 36,300 100,001 0

Hawaii 1,168,403 14,938 0 237,807 128,935 786,723 0

Idaho 598,638 20,705 0 377,881 14,052 0 186,000

Illinois 7,910,559 62,240 31,607 1,237,820 1,377,669 405,228 4,795,996

Indiana 3,833,462 53,832 8,150 1,343,907 460,953 113,400 1,853,220

Iowa 1,669,054 34,873 7,782 635,226 435,492 0 555,682

Kansas 1,903,624 14,044 15,781 288,095 327,403 0 1,258,301

Kentucky 4,050,273 6,419 21,540 145,399 2,190,482 85,697 1,600,737

Louisiana 3,411,211 100,823 8,085 762,163 705,285 663,655 1,171,200

Maine 368,811 10,566 8,770 43,690 192,225 0 113,560

Maryland 4,493,237 9,908 6,123 346,418 348,121 249,600 3,533,067

Massachusetts 7,942,671 43,421 14,171 1,317,567 1,768,248 159,180 4,640,084

Michigan 5,866,881 54,175 12,964 366,966 859,317 283,846 4,289,613

Minnesota 3,092,542 38,944 4,960 1,707,947 406,914 0 933,777

Mississippi 1,418,405 86,727 0 988,496 0 0 343,182

Missouri 3,711,957 49,173 19,101 600,252 449,297 223,971 2,370,164

Montana 376,922 8,734 8,778 72,215 183,824 0 103,371

N. Mariana Islands 72,737 1,081 0 71,656 0 0 0

Navajo Nation 19,080 836 0 18,244 0 0 0

Nebraska 998,770 26,423 0 219,594 37,864 0 714,889

Nevada 1,999,825 13,712 8,323 59,000 73,095 0 1,845,695

New Hampshire 562,737 8,516 10,000 86,706 305,451 0 152,064

New Jersey 7,116,424 60,693 3,400 1,156,623 1,666,422 115,378 4,113,907

New Mexico 1,152,067 16,238 8,256 501,653 172,567 453,353 0

New York 14,764,779 35,519 44,587 1,371,569 1,657,155 1,682,822 9,973,127

North Carolina 5,366,551 37,318 18,964 580,495 1,974,056 108,666 2,647,052

North Dakota 350,292 5,414 2,694 78,529 263,655 0 0

Ohio 8,788,460 64,492 31,964 1,498,349 1,822,242 123,850 5,247,564

Oklahoma 2,491,284 10,318 31,117 241,483 950,915 0 1,257,451

Oregon 2,413,155 13,140 24,170 188,470 830,806 0 1,356,569

Pennsylvania 8,692,491 58,224 57,237 425,487 2,978,041 0 5,173,502

Puerto Rico 5,552,363 20,268 20,177 384,807 1,688,215 0 3,438,896

Rhode Island 911,235 1,812 0 107,302 250,585 0 551,536

South Carolina 2,785,309 14,508 19,828 180,888 1,218,197 0 1,351,888

South Dakota 349,953 10,139 1,592 43,056 167,166 0 128,000

Tennessee 4,625,703 22,345 49,153 428,243 2,499,282 687,096 939,584

Texas 18,832,904 189,890 115,111 1,429,442 3,795,822 1,253,442 12,049,197

Utah 2,403,787 20,075 15,000 274,446 934,364 0 1,159,902

Vermont 196,255 5,245 5,830 0 185,180 0 0

Virgin Islands 67,889 2,550 0 0 65,339 0 0

Virginia 4,635,684 11,756 31,277 98,415 1,285,803 0 3,208,433

Washington 4,265,055 47,921 18,679 1,255,343 756,649 374,556 1,811,906

West Virginia 958,526 8,711 26,897 65,669 527,486 0 329,764

Wisconsin 2,806,236 59,710 8,550 842,048 620,506 205,247 1,070,175

Wyoming 296,668 6,591 0 24,999 265,078 0 0

Tribes - Region 1 41,000 0 0 0 41,000 0 0

Tribes - Region 5 18,788 4,068 0 14,720 0 0 0

Tribes - Region 6 0 0 0 0 0 0 0

Tribes - Region 8 12,160 0 2,020 10,140 0 0 0

Tribes - Region 9 62,055 18,855 0 31,200 12,000 0 0

Total 229,237,740 1,790,743 878,262 34,828,693 49,758,358 17,269,919 124,711,765 1

 The UCMR data are not representative at the state-level.

State 1

Total 

Population 

Served

Pop. Served by Small Systems 

(serving ≤10,000 people)

Pop. Served by Large Systems 

(serving 10,001 - 100,000 people)

Pop. Served by Very Large Systems 

(serving >100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 5 of 50

Table B3. BDE-100 - UCMR 2 Assessment Monitoring Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 946 120 13 3 36 62 0 6

Alaska 49 9 3 2 2 1 0 1

American Samoa 4 1 0 0 0 1 0 0

Arizona 951 69 13 0 41 5 1 9

Arkansas 289 61 9 4 17 28 0 3

California 6,725 393 32 14 123 152 8 64

Colorado 505 68 5 6 13 34 0 10

Connecticut 329 41 5 1 7 23 0 5

Delaware 106 10 4 0 2 1 0 3

District of Columbia 8 1 0 0 0 0 0 1

Florida 1,152 231 28 0 161 7 23 12

Georgia 570 110 14 5 27 51 1 12

Guam 246 3 0 0 0 2 1 0

Hawaii 315 18 3 0 8 5 2 0

Idaho 257 22 7 0 13 1 0 1

Illinois 839 141 22 5 61 42 3 8

Indiana 399 99 16 2 56 18 1 6

Iowa 233 54 14 1 24 12 0 3

Kansas 224 46 7 4 12 17 0 6

Kentucky 433 107 2 4 10 86 1 4

Louisiana 606 92 25 3 36 21 3 4

Maine 89 19 4 2 3 9 0 1

Maryland 180 38 7 2 13 12 1 3

Massachusetts 965 126 9 3 55 50 1 8

Michigan 393 77 21 2 18 29 2 5

Minnesota 356 91 15 1 64 9 0 2

Mississippi 636 78 30 0 46 0 0 2

Missouri 464 75 16 4 31 19 1 4

Montana 112 13 4 2 1 5 0 1

N. Mariana Islands 69 2 1 0 1 0 0 0

Navajo Nation 12 2 1 0 1 0 0 0

Nebraska 238 22 8 0 10 2 0 2

Nevada 184 15 4 1 4 2 0 4

New Hampshire 155 24 5 1 4 13 0 1

New Jersey 1,055 131 14 1 55 49 1 11

New Mexico 331 32 7 1 18 5 1 0

New York 1,542 154 18 11 47 59 5 14

North Carolina 1,032 126 16 5 27 65 1 12

North Dakota 50 12 2 1 3 6 0 0

Ohio 525 153 20 5 59 58 1 10

Oklahoma 422 62 6 8 11 34 0 3

Oregon 365 55 6 4 10 30 0 5

Pennsylvania 1,218 171 24 13 24 92 0 18

Puerto Rico 655 83 6 5 17 47 0 8

Rhode Island 92 13 2 0 4 5 0 2

South Carolina 321 63 6 3 8 41 0 5

South Dakota 87 15 4 1 3 6 0 1

Tennessee 569 121 5 8 16 87 1 4

Texas 2,200 295 63 23 62 122 1 24

Utah 513 54 6 2 14 25 0 7

Vermont 46 11 3 2 0 6 0 0

Virgin Islands 20 4 2 0 0 2 0 0

Virginia 409 73 9 6 4 43 0 11

Washington 834 93 18 3 46 20 2 4

West Virginia 142 36 3 6 3 22 0 2

Wisconsin 561 78 19 1 38 16 1 3

Wyoming 56 11 3 0 1 7 0 0

Tribes - Region 1 4 1 0 0 0 1 0 0

Tribes - Region 5 10 4 3 0 1 0 0 0

Tribes - Region 6 0 0 0 0 0 0 0 0

Tribes - Region 8 6 2 0 1 1 0 0 0

Tribes - Region 9 45 9 6 0 2 1 0 0

Total 32,149 4,140 618 182 1,374 1,568 63 335 1

 The UCMR data are not representative at the state-level.

Number of Very Large Systems 

(serving >100,000 people)

State 1

Total 

Number of 

Samples

Total 

Number of 

Systems

Number of Small Systems 

(serving ≤10,000 people)

Number of Large Systems 

(serving 10,001 - 100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 6 of 50

Table B3. BDE-100 - UCMR 2 Assessment Monitoring Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 4,249,148 64,214 15,859 850,382 1,612,450 0 1,706,245

Alaska 234,237 6,025 9,791 59,290 23,965 0 135,166

American Samoa 45,000 0 0 0 45,000 0 0

Arizona 4,417,574 32,953 0 999,514 110,587 675,445 2,599,075

Arkansas 1,771,814 31,449 19,189 395,797 638,748 0 686,632

California 32,516,672 101,399 70,338 3,738,533 6,626,442 1,088,908 20,891,052

Colorado 4,395,410 12,154 13,190 312,380 1,020,990 0 3,036,696

Connecticut 2,423,307 6,961 7,784 101,145 929,609 0 1,377,809

Delaware 550,332 14,255 0 54,443 36,130 0 445,504

District of Columbia 783,055 0 0 0 0 0 783,055

Florida 15,964,524 85,230 0 5,601,752 190,650 7,266,168 2,820,724

Georgia 6,323,497 30,214 19,473 555,035 1,594,334 163,688 3,960,753

Guam 136,301 0 0 0 36,300 100,001 0

Hawaii 1,168,403 14,938 0 237,807 128,935 786,723 0

Idaho 598,638 20,705 0 377,881 14,052 0 186,000

Illinois 7,910,559 62,240 31,607 1,237,820 1,377,669 405,228 4,795,996

Indiana 3,833,462 53,832 8,150 1,343,907 460,953 113,400 1,853,220

Iowa 1,669,054 34,873 7,782 635,226 435,492 0 555,682

Kansas 1,903,624 14,044 15,781 288,095 327,403 0 1,258,301

Kentucky 4,050,273 6,419 21,540 145,399 2,190,482 85,697 1,600,737

Louisiana 3,411,211 100,823 8,085 762,163 705,285 663,655 1,171,200

Maine 368,811 10,566 8,770 43,690 192,225 0 113,560

Maryland 4,493,237 9,908 6,123 346,418 348,121 249,600 3,533,067

Massachusetts 7,942,671 43,421 14,171 1,317,567 1,768,248 159,180 4,640,084

Michigan 5,866,881 54,175 12,964 366,966 859,317 283,846 4,289,613

Minnesota 3,092,542 38,944 4,960 1,707,947 406,914 0 933,777

Mississippi 1,418,405 86,727 0 988,496 0 0 343,182

Missouri 3,711,957 49,173 19,101 600,252 449,297 223,971 2,370,164

Montana 376,922 8,734 8,778 72,215 183,824 0 103,371

N. Mariana Islands 72,737 1,081 0 71,656 0 0 0

Navajo Nation 19,080 836 0 18,244 0 0 0

Nebraska 998,770 26,423 0 219,594 37,864 0 714,889

Nevada 1,999,825 13,712 8,323 59,000 73,095 0 1,845,695

New Hampshire 562,737 8,516 10,000 86,706 305,451 0 152,064

New Jersey 7,116,424 60,693 3,400 1,156,623 1,666,422 115,378 4,113,907

New Mexico 1,152,067 16,238 8,256 501,653 172,567 453,353 0

New York 14,764,779 35,519 44,587 1,371,569 1,657,155 1,682,822 9,973,127

North Carolina 5,366,551 37,318 18,964 580,495 1,974,056 108,666 2,647,052

North Dakota 350,292 5,414 2,694 78,529 263,655 0 0

Ohio 8,788,460 64,492 31,964 1,498,349 1,822,242 123,850 5,247,564

Oklahoma 2,491,284 10,318 31,117 241,483 950,915 0 1,257,451

Oregon 2,413,155 13,140 24,170 188,470 830,806 0 1,356,569

Pennsylvania 8,692,491 58,224 57,237 425,487 2,978,041 0 5,173,502

Puerto Rico 5,552,363 20,268 20,177 384,807 1,688,215 0 3,438,896

Rhode Island 911,235 1,812 0 107,302 250,585 0 551,536

South Carolina 2,785,309 14,508 19,828 180,888 1,218,197 0 1,351,888

South Dakota 349,953 10,139 1,592 43,056 167,166 0 128,000

Tennessee 4,625,703 22,345 49,153 428,243 2,499,282 687,096 939,584

Texas 18,832,904 189,890 115,111 1,429,442 3,795,822 1,253,442 12,049,197

Utah 2,403,787 20,075 15,000 274,446 934,364 0 1,159,902

Vermont 196,255 5,245 5,830 0 185,180 0 0

Virgin Islands 67,889 2,550 0 0 65,339 0 0

Virginia 4,635,684 11,756 31,277 98,415 1,285,803 0 3,208,433

Washington 4,265,055 47,921 18,679 1,255,343 756,649 374,556 1,811,906

West Virginia 958,526 8,711 26,897 65,669 527,486 0 329,764

Wisconsin 2,806,236 59,710 8,550 842,048 620,506 205,247 1,070,175

Wyoming 296,668 6,591 0 24,999 265,078 0 0

Tribes - Region 1 41,000 0 0 0 41,000 0 0

Tribes - Region 5 18,788 4,068 0 14,720 0 0 0

Tribes - Region 6 0 0 0 0 0 0 0

Tribes - Region 8 12,160 0 2,020 10,140 0 0 0

Tribes - Region 9 62,055 18,855 0 31,200 12,000 0 0

Total 229,237,740 1,790,743 878,262 34,828,693 49,758,358 17,269,919 124,711,765 1

 The UCMR data are not representative at the state-level.

State 1

Total 

Population 

Served

Pop. Served by Small Systems 

(serving ≤10,000 people)

Pop. Served by Large Systems 

(serving 10,001 - 100,000 people)

Pop. Served by Very Large Systems 

(serving >100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 7 of 50

Table B4. BDE-153 - UCMR 2 Assessment Monitoring Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 946 120 13 3 36 62 0 6

Alaska 49 9 3 2 2 1 0 1

American Samoa 4 1 0 0 0 1 0 0

Arizona 951 69 13 0 41 5 1 9

Arkansas 289 61 9 4 17 28 0 3

California 6,725 393 32 14 123 152 8 64

Colorado 505 68 5 6 13 34 0 10

Connecticut 329 41 5 1 7 23 0 5

Delaware 106 10 4 0 2 1 0 3

District of Columbia 8 1 0 0 0 0 0 1

Florida 1,152 231 28 0 161 7 23 12

Georgia 570 110 14 5 27 51 1 12

Guam 246 3 0 0 0 2 1 0

Hawaii 315 18 3 0 8 5 2 0

Idaho 257 22 7 0 13 1 0 1

Illinois 839 141 22 5 61 42 3 8

Indiana 399 99 16 2 56 18 1 6

Iowa 233 54 14 1 24 12 0 3

Kansas 224 46 7 4 12 17 0 6

Kentucky 433 107 2 4 10 86 1 4

Louisiana 606 92 25 3 36 21 3 4

Maine 89 19 4 2 3 9 0 1

Maryland 180 38 7 2 13 12 1 3

Massachusetts 965 126 9 3 55 50 1 8

Michigan 393 77 21 2 18 29 2 5

Minnesota 356 91 15 1 64 9 0 2

Mississippi 636 78 30 0 46 0 0 2

Missouri 464 75 16 4 31 19 1 4

Montana 112 13 4 2 1 5 0 1

N. Mariana Islands 69 2 1 0 1 0 0 0

Navajo Nation 12 2 1 0 1 0 0 0

Nebraska 238 22 8 0 10 2 0 2

Nevada 184 15 4 1 4 2 0 4

New Hampshire 155 24 5 1 4 13 0 1

New Jersey 1,055 131 14 1 55 49 1 11

New Mexico 331 32 7 1 18 5 1 0

New York 1,542 154 18 11 47 59 5 14

North Carolina 1,032 126 16 5 27 65 1 12

North Dakota 50 12 2 1 3 6 0 0

Ohio 525 153 20 5 59 58 1 10

Oklahoma 422 62 6 8 11 34 0 3

Oregon 365 55 6 4 10 30 0 5

Pennsylvania 1,218 171 24 13 24 92 0 18

Puerto Rico 655 83 6 5 17 47 0 8

Rhode Island 92 13 2 0 4 5 0 2

South Carolina 321 63 6 3 8 41 0 5

South Dakota 87 15 4 1 3 6 0 1

Tennessee 569 121 5 8 16 87 1 4

Texas 2,190 295 63 23 62 122 1 24

Utah 513 54 6 2 14 25 0 7

Vermont 46 11 3 2 0 6 0 0

Virgin Islands 20 4 2 0 0 2 0 0

Virginia 409 73 9 6 4 43 0 11

Washington 834 93 18 3 46 20 2 4

West Virginia 142 36 3 6 3 22 0 2

Wisconsin 561 78 19 1 38 16 1 3

Wyoming 56 11 3 0 1 7 0 0

Tribes - Region 1 4 1 0 0 0 1 0 0

Tribes - Region 5 10 4 3 0 1 0 0 0

Tribes - Region 6 0 0 0 0 0 0 0 0

Tribes - Region 8 6 2 0 1 1 0 0 0

Tribes - Region 9 45 9 6 0 2 1 0 0

Total 32,139 4,140 618 182 1,374 1,568 63 335 1

 The UCMR data are not representative at the state-level.

Number of Very Large Systems 

(serving >100,000 people)

State 1

Total 

Number of 

Samples

Total 

Number of 

Systems

Number of Small Systems 

(serving ≤10,000 people)

Number of Large Systems 

(serving 10,001 - 100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 8 of 50

Table B4. BDE-153 - UCMR 2 Assessment Monitoring Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 4,249,148 64,214 15,859 850,382 1,612,450 0 1,706,245

Alaska 234,237 6,025 9,791 59,290 23,965 0 135,166

American Samoa 45,000 0 0 0 45,000 0 0

Arizona 4,417,574 32,953 0 999,514 110,587 675,445 2,599,075

Arkansas 1,771,814 31,449 19,189 395,797 638,748 0 686,632

California 32,516,672 101,399 70,338 3,738,533 6,626,442 1,088,908 20,891,052

Colorado 4,395,410 12,154 13,190 312,380 1,020,990 0 3,036,696

Connecticut 2,423,307 6,961 7,784 101,145 929,609 0 1,377,809

Delaware 550,332 14,255 0 54,443 36,130 0 445,504

District of Columbia 783,055 0 0 0 0 0 783,055

Florida 15,964,524 85,230 0 5,601,752 190,650 7,266,168 2,820,724

Georgia 6,323,497 30,214 19,473 555,035 1,594,334 163,688 3,960,753

Guam 136,301 0 0 0 36,300 100,001 0

Hawaii 1,168,403 14,938 0 237,807 128,935 786,723 0

Idaho 598,638 20,705 0 377,881 14,052 0 186,000

Illinois 7,910,559 62,240 31,607 1,237,820 1,377,669 405,228 4,795,996

Indiana 3,833,462 53,832 8,150 1,343,907 460,953 113,400 1,853,220

Iowa 1,669,054 34,873 7,782 635,226 435,492 0 555,682

Kansas 1,903,624 14,044 15,781 288,095 327,403 0 1,258,301

Kentucky 4,050,273 6,419 21,540 145,399 2,190,482 85,697 1,600,737

Louisiana 3,411,211 100,823 8,085 762,163 705,285 663,655 1,171,200

Maine 368,811 10,566 8,770 43,690 192,225 0 113,560

Maryland 4,493,237 9,908 6,123 346,418 348,121 249,600 3,533,067

Massachusetts 7,942,671 43,421 14,171 1,317,567 1,768,248 159,180 4,640,084

Michigan 5,866,881 54,175 12,964 366,966 859,317 283,846 4,289,613

Minnesota 3,092,542 38,944 4,960 1,707,947 406,914 0 933,777

Mississippi 1,418,405 86,727 0 988,496 0 0 343,182

Missouri 3,711,957 49,173 19,101 600,252 449,297 223,971 2,370,164

Montana 376,922 8,734 8,778 72,215 183,824 0 103,371

N. Mariana Islands 72,737 1,081 0 71,656 0 0 0

Navajo Nation 19,080 836 0 18,244 0 0 0

Nebraska 998,770 26,423 0 219,594 37,864 0 714,889

Nevada 1,999,825 13,712 8,323 59,000 73,095 0 1,845,695

New Hampshire 562,737 8,516 10,000 86,706 305,451 0 152,064

New Jersey 7,116,424 60,693 3,400 1,156,623 1,666,422 115,378 4,113,907

New Mexico 1,152,067 16,238 8,256 501,653 172,567 453,353 0

New York 14,764,779 35,519 44,587 1,371,569 1,657,155 1,682,822 9,973,127

North Carolina 5,366,551 37,318 18,964 580,495 1,974,056 108,666 2,647,052

North Dakota 350,292 5,414 2,694 78,529 263,655 0 0

Ohio 8,788,460 64,492 31,964 1,498,349 1,822,242 123,850 5,247,564

Oklahoma 2,491,284 10,318 31,117 241,483 950,915 0 1,257,451

Oregon 2,413,155 13,140 24,170 188,470 830,806 0 1,356,569

Pennsylvania 8,692,491 58,224 57,237 425,487 2,978,041 0 5,173,502

Puerto Rico 5,552,363 20,268 20,177 384,807 1,688,215 0 3,438,896

Rhode Island 911,235 1,812 0 107,302 250,585 0 551,536

South Carolina 2,785,309 14,508 19,828 180,888 1,218,197 0 1,351,888

South Dakota 349,953 10,139 1,592 43,056 167,166 0 128,000

Tennessee 4,625,703 22,345 49,153 428,243 2,499,282 687,096 939,584

Texas 18,832,904 189,890 115,111 1,429,442 3,795,822 1,253,442 12,049,197

Utah 2,403,787 20,075 15,000 274,446 934,364 0 1,159,902

Vermont 196,255 5,245 5,830 0 185,180 0 0

Virgin Islands 67,889 2,550 0 0 65,339 0 0

Virginia 4,635,684 11,756 31,277 98,415 1,285,803 0 3,208,433

Washington 4,265,055 47,921 18,679 1,255,343 756,649 374,556 1,811,906

West Virginia 958,526 8,711 26,897 65,669 527,486 0 329,764

Wisconsin 2,806,236 59,710 8,550 842,048 620,506 205,247 1,070,175

Wyoming 296,668 6,591 0 24,999 265,078 0 0

Tribes - Region 1 41,000 0 0 0 41,000 0 0

Tribes - Region 5 18,788 4,068 0 14,720 0 0 0

Tribes - Region 6 0 0 0 0 0 0 0

Tribes - Region 8 12,160 0 2,020 10,140 0 0 0

Tribes - Region 9 62,055 18,855 0 31,200 12,000 0 0

Total 229,237,740 1,790,743 878,262 34,828,693 49,758,358 17,269,919 124,711,765 1

 The UCMR data are not representative at the state-level.

State 1

Total 

Population 

Served

Pop. Served by Small Systems 

(serving ≤10,000 people)

Pop. Served by Large Systems 

(serving 10,001 - 100,000 people)

Pop. Served by Very Large Systems 

(serving >100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 9 of 50

Table B5. Dimethoate - UCMR 2 Assessment Monitoring Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 946 120 13 3 36 62 0 6

Alaska 49 9 3 2 2 1 0 1

American Samoa 4 1 0 0 0 1 0 0

Arizona 951 69 13 0 41 5 1 9

Arkansas 289 61 9 4 17 28 0 3

California 6,725 393 32 14 123 152 8 64

Colorado 505 68 5 6 13 34 0 10

Connecticut 329 41 5 1 7 23 0 5

Delaware 106 10 4 0 2 1 0 3

District of Columbia 8 1 0 0 0 0 0 1

Florida 1,152 231 28 0 161 7 23 12

Georgia 570 110 14 5 27 51 1 12

Guam 246 3 0 0 0 2 1 0

Hawaii 315 18 3 0 8 5 2 0

Idaho 257 22 7 0 13 1 0 1

Illinois 839 141 22 5 61 42 3 8

Indiana 399 99 16 2 56 18 1 6

Iowa 233 54 14 1 24 12 0 3

Kansas 224 46 7 4 12 17 0 6

Kentucky 433 107 2 4 10 86 1 4

Louisiana 607 92 25 3 36 21 3 4

Maine 89 19 4 2 3 9 0 1

Maryland 180 38 7 2 13 12 1 3

Massachusetts 965 126 9 3 55 50 1 8

Michigan 393 77 21 2 18 29 2 5

Minnesota 356 91 15 1 64 9 0 2

Mississippi 636 78 30 0 46 0 0 2

Missouri 464 75 16 4 31 19 1 4

Montana 112 13 4 2 1 5 0 1

N. Mariana Islands 69 2 1 0 1 0 0 0

Navajo Nation 12 2 1 0 1 0 0 0

Nebraska 238 22 8 0 10 2 0 2

Nevada 184 15 4 1 4 2 0 4

New Hampshire 155 24 5 1 4 13 0 1

New Jersey 1,055 131 14 1 55 49 1 11

New Mexico 331 32 7 1 18 5 1 0

New York 1,542 154 18 11 47 59 5 14

North Carolina 1,032 126 16 5 27 65 1 12

North Dakota 50 12 2 1 3 6 0 0

Ohio 525 153 20 5 59 58 1 10

Oklahoma 422 62 6 8 11 34 0 3

Oregon 365 55 6 4 10 30 0 5

Pennsylvania 1,218 171 24 13 24 92 0 18

Puerto Rico 655 83 6 5 17 47 0 8

Rhode Island 92 13 2 0 4 5 0 2

South Carolina 321 63 6 3 8 41 0 5

South Dakota 87 15 4 1 3 6 0 1

Tennessee 569 121 5 8 16 87 1 4

Texas 2,200 295 63 23 62 122 1 24

Utah 513 54 6 2 14 25 0 7

Vermont 46 11 3 2 0 6 0 0

Virgin Islands 20 4 2 0 0 2 0 0

Virginia 409 73 9 6 4 43 0 11

Washington 834 93 18 3 46 20 2 4

West Virginia 142 36 3 6 3 22 0 2

Wisconsin 561 78 19 1 38 16 1 3

Wyoming 56 11 3 0 1 7 0 0

Tribes - Region 1 4 1 0 0 0 1 0 0

Tribes - Region 5 10 4 3 0 1 0 0 0

Tribes - Region 6 0 0 0 0 0 0 0 0

Tribes - Region 8 6 2 0 1 1 0 0 0

Tribes - Region 9 45 9 6 0 2 1 0 0

Total 32,150 4,140 618 182 1,374 1,568 63 335 1

 The UCMR data are not representative at the state-level.

Number of Very Large Systems 

(serving >100,000 people)

State 1

Total 

Number of 

Samples

Total 

Number of 

Systems

Number of Small Systems 

(serving ≤10,000 people)

Number of Large Systems 

(serving 10,001 - 100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 10 of 50

Table B5. Dimethoate - UCMR 2 Assessment Monitoring Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 4,249,148 64,214 15,859 850,382 1,612,450 0 1,706,245

Alaska 234,237 6,025 9,791 59,290 23,965 0 135,166

American Samoa 45,000 0 0 0 45,000 0 0

Arizona 4,417,574 32,953 0 999,514 110,587 675,445 2,599,075

Arkansas 1,771,814 31,449 19,189 395,797 638,748 0 686,632

California 32,516,672 101,399 70,338 3,738,533 6,626,442 1,088,908 20,891,052

Colorado 4,395,410 12,154 13,190 312,380 1,020,990 0 3,036,696

Connecticut 2,423,307 6,961 7,784 101,145 929,609 0 1,377,809

Delaware 550,332 14,255 0 54,443 36,130 0 445,504

District of Columbia 783,055 0 0 0 0 0 783,055

Florida 15,964,524 85,230 0 5,601,752 190,650 7,266,168 2,820,724

Georgia 6,323,497 30,214 19,473 555,035 1,594,334 163,688 3,960,753

Guam 136,301 0 0 0 36,300 100,001 0

Hawaii 1,168,403 14,938 0 237,807 128,935 786,723 0

Idaho 598,638 20,705 0 377,881 14,052 0 186,000

Illinois 7,910,559 62,240 31,607 1,237,820 1,377,669 405,228 4,795,996

Indiana 3,833,462 53,832 8,150 1,343,907 460,953 113,400 1,853,220

Iowa 1,669,054 34,873 7,782 635,226 435,492 0 555,682

Kansas 1,903,624 14,044 15,781 288,095 327,403 0 1,258,301

Kentucky 4,050,273 6,419 21,540 145,399 2,190,482 85,697 1,600,737

Louisiana 3,411,211 100,823 8,085 762,163 705,285 663,655 1,171,200

Maine 368,811 10,566 8,770 43,690 192,225 0 113,560

Maryland 4,493,237 9,908 6,123 346,418 348,121 249,600 3,533,067

Massachusetts 7,942,671 43,421 14,171 1,317,567 1,768,248 159,180 4,640,084

Michigan 5,866,881 54,175 12,964 366,966 859,317 283,846 4,289,613

Minnesota 3,092,542 38,944 4,960 1,707,947 406,914 0 933,777

Mississippi 1,418,405 86,727 0 988,496 0 0 343,182

Missouri 3,711,957 49,173 19,101 600,252 449,297 223,971 2,370,164

Montana 376,922 8,734 8,778 72,215 183,824 0 103,371

N. Mariana Islands 72,737 1,081 0 71,656 0 0 0

Navajo Nation 19,080 836 0 18,244 0 0 0

Nebraska 998,770 26,423 0 219,594 37,864 0 714,889

Nevada 1,999,825 13,712 8,323 59,000 73,095 0 1,845,695

New Hampshire 562,737 8,516 10,000 86,706 305,451 0 152,064

New Jersey 7,116,424 60,693 3,400 1,156,623 1,666,422 115,378 4,113,907

New Mexico 1,152,067 16,238 8,256 501,653 172,567 453,353 0

New York 14,764,779 35,519 44,587 1,371,569 1,657,155 1,682,822 9,973,127

North Carolina 5,366,551 37,318 18,964 580,495 1,974,056 108,666 2,647,052

North Dakota 350,292 5,414 2,694 78,529 263,655 0 0

Ohio 8,788,460 64,492 31,964 1,498,349 1,822,242 123,850 5,247,564

Oklahoma 2,491,284 10,318 31,117 241,483 950,915 0 1,257,451

Oregon 2,413,155 13,140 24,170 188,470 830,806 0 1,356,569

Pennsylvania 8,692,491 58,224 57,237 425,487 2,978,041 0 5,173,502

Puerto Rico 5,552,363 20,268 20,177 384,807 1,688,215 0 3,438,896

Rhode Island 911,235 1,812 0 107,302 250,585 0 551,536

South Carolina 2,785,309 14,508 19,828 180,888 1,218,197 0 1,351,888

South Dakota 349,953 10,139 1,592 43,056 167,166 0 128,000

Tennessee 4,625,703 22,345 49,153 428,243 2,499,282 687,096 939,584

Texas 18,832,904 189,890 115,111 1,429,442 3,795,822 1,253,442 12,049,197

Utah 2,403,787 20,075 15,000 274,446 934,364 0 1,159,902

Vermont 196,255 5,245 5,830 0 185,180 0 0

Virgin Islands 67,889 2,550 0 0 65,339 0 0

Virginia 4,635,684 11,756 31,277 98,415 1,285,803 0 3,208,433

Washington 4,265,055 47,921 18,679 1,255,343 756,649 374,556 1,811,906

West Virginia 958,526 8,711 26,897 65,669 527,486 0 329,764

Wisconsin 2,806,236 59,710 8,550 842,048 620,506 205,247 1,070,175

Wyoming 296,668 6,591 0 24,999 265,078 0 0

Tribes - Region 1 41,000 0 0 0 41,000 0 0

Tribes - Region 5 18,788 4,068 0 14,720 0 0 0

Tribes - Region 6 0 0 0 0 0 0 0

Tribes - Region 8 12,160 0 2,020 10,140 0 0 0

Tribes - Region 9 62,055 18,855 0 31,200 12,000 0 0

Total 229,237,740 1,790,743 878,262 34,828,693 49,758,358 17,269,919 124,711,765 1

 The UCMR data are not representative at the state-level.

State 1

Total 

Population 

Served

Pop. Served by Small Systems 

(serving ≤10,000 people)

Pop. Served by Large Systems 

(serving 10,001 - 100,000 people)

Pop. Served by Very Large Systems 

(serving >100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 11 of 50

Table B6. 1,3-Dinitrobenzene - UCMR 2 Assessment Monitoring Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 946 120 13 3 36 62 0 6

Alaska 48 8 3 2 1 1 0 1

American Samoa 4 1 0 0 0 1 0 0

Arizona 952 69 13 0 41 5 1 9

Arkansas 290 61 9 4 17 28 0 3

California 6,724 393 32 14 123 152 8 64

Colorado 503 68 5 6 13 34 0 10

Connecticut 329 41 5 1 7 23 0 5

Delaware 106 10 4 0 2 1 0 3

District of Columbia 8 1 0 0 0 0 0 1

Florida 1,155 231 28 0 161 7 23 12

Georgia 570 110 14 5 27 51 1 12

Guam 245 3 0 0 0 2 1 0

Hawaii 313 18 3 0 8 5 2 0

Idaho 256 22 7 0 13 1 0 1

Illinois 839 141 22 5 61 42 3 8

Indiana 399 99 16 2 56 18 1 6

Iowa 234 54 14 1 24 12 0 3

Kansas 226 46 7 4 12 17 0 6

Kentucky 432 107 2 4 10 86 1 4

Louisiana 606 92 25 3 36 21 3 4

Maine 89 19 4 2 3 9 0 1

Maryland 180 38 7 2 13 12 1 3

Massachusetts 965 126 9 3 55 50 1 8

Michigan 393 77 21 2 18 29 2 5

Minnesota 356 91 15 1 64 9 0 2

Mississippi 635 78 30 0 46 0 0 2

Missouri 463 75 16 4 31 19 1 4

Montana 111 13 4 2 1 5 0 1

N. Mariana Islands 68 2 1 0 1 0 0 0

Navajo Nation 12 2 1 0 1 0 0 0

Nebraska 238 22 8 0 10 2 0 2

Nevada 184 15 4 1 4 2 0 4

New Hampshire 155 24 5 1 4 13 0 1

New Jersey 1,058 131 14 1 55 49 1 11

New Mexico 331 32 7 1 18 5 1 0

New York 1,538 154 18 11 47 59 5 14

North Carolina 1,029 126 16 5 27 65 1 12

North Dakota 50 12 2 1 3 6 0 0

Ohio 525 153 20 5 59 58 1 10

Oklahoma 434 62 6 8 11 34 0 3

Oregon 365 55 6 4 10 30 0 5

Pennsylvania 1,218 171 24 13 24 92 0 18

Puerto Rico 645 83 6 5 17 47 0 8

Rhode Island 91 13 2 0 4 5 0 2

South Carolina 321 63 6 3 8 41 0 5

South Dakota 87 15 4 1 3 6 0 1

Tennessee 569 121 5 8 16 87 1 4

Texas 2,199 295 63 23 62 122 1 24

Utah 514 54 6 2 14 25 0 7

Vermont 46 11 3 2 0 6 0 0

Virgin Islands 20 4 2 0 0 2 0 0

Virginia 409 73 9 6 4 43 0 11

Washington 844 93 18 3 46 20 2 4

West Virginia 142 36 3 6 3 22 0 2

Wisconsin 561 78 19 1 38 16 1 3

Wyoming 57 11 3 0 1 7 0 0

Tribes - Region 1 4 1 0 0 0 1 0 0

Tribes - Region 5 10 4 3 0 1 0 0 0

Tribes - Region 6 0 0 0 0 0 0 0 0

Tribes - Region 8 6 2 0 1 1 0 0 0

Tribes - Region 9 45 9 6 0 2 1 0 0

Total 32,152 4,139 618 182 1,373 1,568 63 335 1

 The UCMR data are not representative at the state-level.

State 1

Total 

Number of 

Samples

Total 

Number of 

Systems

Number of Small Systems 

(serving ≤10,000 people)

Number of Large Systems 

(serving 10,001 - 100,000 people)

Number of Very Large Systems 

(serving >100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 12 of 50

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 4,249,148 64,214 15,859 850,382 1,612,450 0 1,706,245

Alaska 222,237 6,025 9,791 47,290 23,965 0 135,166

American Samoa 45,000 0 0 0 45,000 0 0

Arizona 4,417,574 32,953 0 999,514 110,587 675,445 2,599,075

Arkansas 1,771,814 31,449 19,189 395,797 638,748 0 686,632

California 32,516,672 101,399 70,338 3,738,533 6,626,442 1,088,908 20,891,052

Colorado 4,395,410 12,154 13,190 312,380 1,020,990 0 3,036,696

Connecticut 2,423,307 6,961 7,784 101,145 929,609 0 1,377,809

Delaware 550,332 14,255 0 54,443 36,130 0 445,504

District of Columbia 783,055 0 0 0 0 0 783,055

Florida 15,964,524 85,230 0 5,601,752 190,650 7,266,168 2,820,724

Georgia 6,323,497 30,214 19,473 555,035 1,594,334 163,688 3,960,753

Guam 136,301 0 0 0 36,300 100,001 0

Hawaii 1,168,403 14,938 0 237,807 128,935 786,723 0

Idaho 598,638 20,705 0 377,881 14,052 0 186,000

Illinois 7,910,559 62,240 31,607 1,237,820 1,377,669 405,228 4,795,996

Indiana 3,833,462 53,832 8,150 1,343,907 460,953 113,400 1,853,220

Iowa 1,669,054 34,873 7,782 635,226 435,492 0 555,682

Kansas 1,903,624 14,044 15,781 288,095 327,403 0 1,258,301

Kentucky 4,050,273 6,419 21,540 145,399 2,190,482 85,697 1,600,737

Louisiana 3,411,211 100,823 8,085 762,163 705,285 663,655 1,171,200

Maine 368,811 10,566 8,770 43,690 192,225 0 113,560

Maryland 4,493,237 9,908 6,123 346,418 348,121 249,600 3,533,067

Massachusetts 7,942,671 43,421 14,171 1,317,567 1,768,248 159,180 4,640,084

Michigan 5,866,881 54,175 12,964 366,966 859,317 283,846 4,289,613

Minnesota 3,092,542 38,944 4,960 1,707,947 406,914 0 933,777

Mississippi 1,418,405 86,727 0 988,496 0 0 343,182

Missouri 3,711,957 49,173 19,101 600,252 449,297 223,971 2,370,164

Montana 376,922 8,734 8,778 72,215 183,824 0 103,371

N. Mariana Islands 72,737 1,081 0 71,656 0 0 0

Navajo Nation 19,080 836 0 18,244 0 0 0

Nebraska 998,770 26,423 0 219,594 37,864 0 714,889

Nevada 1,999,825 13,712 8,323 59,000 73,095 0 1,845,695

New Hampshire 562,737 8,516 10,000 86,706 305,451 0 152,064

New Jersey 7,116,424 60,693 3,400 1,156,623 1,666,422 115,378 4,113,907

New Mexico 1,152,067 16,238 8,256 501,653 172,567 453,353 0

New York 14,764,779 35,519 44,587 1,371,569 1,657,155 1,682,822 9,973,127

North Carolina 5,366,551 37,318 18,964 580,495 1,974,056 108,666 2,647,052

North Dakota 350,292 5,414 2,694 78,529 263,655 0 0

Ohio 8,788,460 64,492 31,964 1,498,349 1,822,242 123,850 5,247,564

Oklahoma 2,491,284 10,318 31,117 241,483 950,915 0 1,257,451

Oregon 2,413,155 13,140 24,170 188,470 830,806 0 1,356,569

Pennsylvania 8,692,491 58,224 57,237 425,487 2,978,041 0 5,173,502

Puerto Rico 5,552,363 20,268 20,177 384,807 1,688,215 0 3,438,896

Rhode Island 911,235 1,812 0 107,302 250,585 0 551,536

South Carolina 2,785,309 14,508 19,828 180,888 1,218,197 0 1,351,888

South Dakota 349,953 10,139 1,592 43,056 167,166 0 128,000

Tennessee 4,625,703 22,345 49,153 428,243 2,499,282 687,096 939,584

Texas 18,832,904 189,890 115,111 1,429,442 3,795,822 1,253,442 12,049,197

Utah 2,403,787 20,075 15,000 274,446 934,364 0 1,159,902

Vermont 196,255 5,245 5,830 0 185,180 0 0

Virgin Islands 67,889 2,550 0 0 65,339 0 0

Virginia 4,635,684 11,756 31,277 98,415 1,285,803 0 3,208,433

Washington 4,265,055 47,921 18,679 1,255,343 756,649 374,556 1,811,906

West Virginia 958,526 8,711 26,897 65,669 527,486 0 329,764

Wisconsin 2,806,236 59,710 8,550 842,048 620,506 205,247 1,070,175

Wyoming 296,668 6,591 0 24,999 265,078 0 0

Tribes - Region 1 41,000 0 0 0 41,000 0 0

Tribes - Region 5 18,788 4,068 0 14,720 0 0 0

Tribes - Region 6 0 0 0 0 0 0 0

Tribes - Region 8 12,160 0 2,020 10,140 0 0 0

Tribes - Region 9 62,055 18,855 0 31,200 12,000 0 0

Total 229,225,740 1,790,743 878,262 34,816,693 49,758,358 17,269,919 124,711,765 1

 The UCMR data are not representative at the state-level.

Table B6. 1,3-Dinitrobenzene - UCMR 2 Assessment Monitoring Data - Number of Systems and Population Served by 

State

State 1

Total 

Population 

Served

Pop. Served by Small Systems 

(serving ≤10,000 people)

Pop. Served by Large Systems 

(serving 10,001 - 100,000 people)

Pop. Served by Very Large Systems 

(serving >100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 13 of 50

Table B7. HBB - UCMR 2 Assessment Monitoring Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 946 120 13 3 36 62 0 6

Alaska 49 9 3 2 2 1 0 1

American Samoa 4 1 0 0 0 1 0 0

Arizona 951 69 13 0 41 5 1 9

Arkansas 289 61 9 4 17 28 0 3

California 6,725 393 32 14 123 152 8 64

Colorado 505 68 5 6 13 34 0 10

Connecticut 329 41 5 1 7 23 0 5

Delaware 106 10 4 0 2 1 0 3

District of Columbia 8 1 0 0 0 0 0 1

Florida 1,152 231 28 0 161 7 23 12

Georgia 570 110 14 5 27 51 1 12

Guam 246 3 0 0 0 2 1 0

Hawaii 315 18 3 0 8 5 2 0

Idaho 257 22 7 0 13 1 0 1

Illinois 839 141 22 5 61 42 3 8

Indiana 399 99 16 2 56 18 1 6

Iowa 233 54 14 1 24 12 0 3

Kansas 224 46 7 4 12 17 0 6

Kentucky 433 107 2 4 10 86 1 4

Louisiana 606 92 25 3 36 21 3 4

Maine 89 19 4 2 3 9 0 1

Maryland 180 38 7 2 13 12 1 3

Massachusetts 965 126 9 3 55 50 1 8

Michigan 393 77 21 2 18 29 2 5

Minnesota 356 91 15 1 64 9 0 2

Mississippi 636 78 30 0 46 0 0 2

Missouri 464 75 16 4 31 19 1 4

Montana 112 13 4 2 1 5 0 1

N. Mariana Islands 69 2 1 0 1 0 0 0

Navajo Nation 12 2 1 0 1 0 0 0

Nebraska 238 22 8 0 10 2 0 2

Nevada 184 15 4 1 4 2 0 4

New Hampshire 155 24 5 1 4 13 0 1

New Jersey 1,055 131 14 1 55 49 1 11

New Mexico 331 32 7 1 18 5 1 0

New York 1,542 154 18 11 47 59 5 14

North Carolina 1,032 126 16 5 27 65 1 12

North Dakota 50 12 2 1 3 6 0 0

Ohio 525 153 20 5 59 58 1 10

Oklahoma 422 62 6 8 11 34 0 3

Oregon 365 55 6 4 10 30 0 5

Pennsylvania 1,218 171 24 13 24 92 0 18

Puerto Rico 655 83 6 5 17 47 0 8

Rhode Island 92 13 2 0 4 5 0 2

South Carolina 321 63 6 3 8 41 0 5

South Dakota 87 15 4 1 3 6 0 1

Tennessee 569 121 5 8 16 87 1 4

Texas 2,194 295 63 23 62 122 1 24

Utah 513 54 6 2 14 25 0 7

Vermont 46 11 3 2 0 6 0 0

Virgin Islands 20 4 2 0 0 2 0 0

Virginia 409 73 9 6 4 43 0 11

Washington 834 93 18 3 46 20 2 4

West Virginia 142 36 3 6 3 22 0 2

Wisconsin 561 78 19 1 38 16 1 3

Wyoming 56 11 3 0 1 7 0 0

Tribes - Region 1 4 1 0 0 0 1 0 0

Tribes - Region 5 10 4 3 0 1 0 0 0

Tribes - Region 6 0 0 0 0 0 0 0 0

Tribes - Region 8 6 2 0 1 1 0 0 0

Tribes - Region 9 45 9 6 0 2 1 0 0

Total 32,143 4,140 618 182 1,374 1,568 63 335 1

 The UCMR data are not representative at the state-level.

Number of Very Large Systems 

(serving >100,000 people)

State 1

Total 

Number of 

Samples

Total 

Number of 

Systems

Number of Small Systems 

(serving ≤10,000 people)

Number of Large Systems 

(serving 10,001 - 100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 14 of 50

Table B7. HBB - UCMR 2 Assessment Monitoring Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 4,249,148 64,214 15,859 850,382 1,612,450 0 1,706,245

Alaska 234,237 6,025 9,791 59,290 23,965 0 135,166

American Samoa 45,000 0 0 0 45,000 0 0

Arizona 4,417,574 32,953 0 999,514 110,587 675,445 2,599,075

Arkansas 1,771,814 31,449 19,189 395,797 638,748 0 686,632

California 32,516,672 101,399 70,338 3,738,533 6,626,442 1,088,908 20,891,052

Colorado 4,395,410 12,154 13,190 312,380 1,020,990 0 3,036,696

Connecticut 2,423,307 6,961 7,784 101,145 929,609 0 1,377,809

Delaware 550,332 14,255 0 54,443 36,130 0 445,504

District of Columbia 783,055 0 0 0 0 0 783,055

Florida 15,964,524 85,230 0 5,601,752 190,650 7,266,168 2,820,724

Georgia 6,323,497 30,214 19,473 555,035 1,594,334 163,688 3,960,753

Guam 136,301 0 0 0 36,300 100,001 0

Hawaii 1,168,403 14,938 0 237,807 128,935 786,723 0

Idaho 598,638 20,705 0 377,881 14,052 0 186,000

Illinois 7,910,559 62,240 31,607 1,237,820 1,377,669 405,228 4,795,996

Indiana 3,833,462 53,832 8,150 1,343,907 460,953 113,400 1,853,220

Iowa 1,669,054 34,873 7,782 635,226 435,492 0 555,682

Kansas 1,903,624 14,044 15,781 288,095 327,403 0 1,258,301

Kentucky 4,050,273 6,419 21,540 145,399 2,190,482 85,697 1,600,737

Louisiana 3,411,211 100,823 8,085 762,163 705,285 663,655 1,171,200

Maine 368,811 10,566 8,770 43,690 192,225 0 113,560

Maryland 4,493,237 9,908 6,123 346,418 348,121 249,600 3,533,067

Massachusetts 7,942,671 43,421 14,171 1,317,567 1,768,248 159,180 4,640,084

Michigan 5,866,881 54,175 12,964 366,966 859,317 283,846 4,289,613

Minnesota 3,092,542 38,944 4,960 1,707,947 406,914 0 933,777

Mississippi 1,418,405 86,727 0 988,496 0 0 343,182

Missouri 3,711,957 49,173 19,101 600,252 449,297 223,971 2,370,164

Montana 376,922 8,734 8,778 72,215 183,824 0 103,371

N. Mariana Islands 72,737 1,081 0 71,656 0 0 0

Navajo Nation 19,080 836 0 18,244 0 0 0

Nebraska 998,770 26,423 0 219,594 37,864 0 714,889

Nevada 1,999,825 13,712 8,323 59,000 73,095 0 1,845,695

New Hampshire 562,737 8,516 10,000 86,706 305,451 0 152,064

New Jersey 7,116,424 60,693 3,400 1,156,623 1,666,422 115,378 4,113,907

New Mexico 1,152,067 16,238 8,256 501,653 172,567 453,353 0

New York 14,764,779 35,519 44,587 1,371,569 1,657,155 1,682,822 9,973,127

North Carolina 5,366,551 37,318 18,964 580,495 1,974,056 108,666 2,647,052

North Dakota 350,292 5,414 2,694 78,529 263,655 0 0

Ohio 8,788,460 64,492 31,964 1,498,349 1,822,242 123,850 5,247,564

Oklahoma 2,491,284 10,318 31,117 241,483 950,915 0 1,257,451

Oregon 2,413,155 13,140 24,170 188,470 830,806 0 1,356,569

Pennsylvania 8,692,491 58,224 57,237 425,487 2,978,041 0 5,173,502

Puerto Rico 5,552,363 20,268 20,177 384,807 1,688,215 0 3,438,896

Rhode Island 911,235 1,812 0 107,302 250,585 0 551,536

South Carolina 2,785,309 14,508 19,828 180,888 1,218,197 0 1,351,888

South Dakota 349,953 10,139 1,592 43,056 167,166 0 128,000

Tennessee 4,625,703 22,345 49,153 428,243 2,499,282 687,096 939,584

Texas 18,832,904 189,890 115,111 1,429,442 3,795,822 1,253,442 12,049,197

Utah 2,403,787 20,075 15,000 274,446 934,364 0 1,159,902

Vermont 196,255 5,245 5,830 0 185,180 0 0

Virgin Islands 67,889 2,550 0 0 65,339 0 0

Virginia 4,635,684 11,756 31,277 98,415 1,285,803 0 3,208,433

Washington 4,265,055 47,921 18,679 1,255,343 756,649 374,556 1,811,906

West Virginia 958,526 8,711 26,897 65,669 527,486 0 329,764

Wisconsin 2,806,236 59,710 8,550 842,048 620,506 205,247 1,070,175

Wyoming 296,668 6,591 0 24,999 265,078 0 0

Tribes - Region 1 41,000 0 0 0 41,000 0 0

Tribes - Region 5 18,788 4,068 0 14,720 0 0 0

Tribes - Region 6 0 0 0 0 0 0 0

Tribes - Region 8 12,160 0 2,020 10,140 0 0 0

Tribes - Region 9 62,055 18,855 0 31,200 12,000 0 0

Total 229,237,740 1,790,743 878,262 34,828,693 49,758,358 17,269,919 124,711,765 1

 The UCMR data are not representative at the state-level.

State 1

Total 

Population 

Served

Pop. Served by Small Systems 

(serving ≤10,000 people)

Pop. Served by Large Systems 

(serving 10,001 - 100,000 people)

Pop. Served by Very Large Systems 

(serving >100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 15 of 50

Table B8. RDX - UCMR 2 Assessment Monitoring Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 946 120 13 3 36 62 0 6

Alaska 48 8 3 2 1 1 0 1

American Samoa 4 1 0 0 0 1 0 0

Arizona 952 69 13 0 41 5 1 9

Arkansas 290 61 9 4 17 28 0 3

California 6,724 393 32 14 123 152 8 64

Colorado 503 68 5 6 13 34 0 10

Connecticut 329 41 5 1 7 23 0 5

Delaware 106 10 4 0 2 1 0 3

District of Columbia 8 1 0 0 0 0 0 1

Florida 1,155 231 28 0 161 7 23 12

Georgia 570 110 14 5 27 51 1 12

Guam 245 3 0 0 0 2 1 0

Hawaii 313 18 3 0 8 5 2 0

Idaho 256 22 7 0 13 1 0 1

Illinois 839 141 22 5 61 42 3 8

Indiana 399 99 16 2 56 18 1 6

Iowa 234 54 14 1 24 12 0 3

Kansas 226 46 7 4 12 17 0 6

Kentucky 432 107 2 4 10 86 1 4

Louisiana 606 92 25 3 36 21 3 4

Maine 89 19 4 2 3 9 0 1

Maryland 180 38 7 2 13 12 1 3

Massachusetts 965 126 9 3 55 50 1 8

Michigan 393 77 21 2 18 29 2 5

Minnesota 356 91 15 1 64 9 0 2

Mississippi 635 78 30 0 46 0 0 2

Missouri 463 75 16 4 31 19 1 4

Montana 111 13 4 2 1 5 0 1

N. Mariana Islands 68 2 1 0 1 0 0 0

Navajo Nation 12 2 1 0 1 0 0 0

Nebraska 238 22 8 0 10 2 0 2

Nevada 184 15 4 1 4 2 0 4

New Hampshire 155 24 5 1 4 13 0 1

New Jersey 1,058 131 14 1 55 49 1 11

New Mexico 331 32 7 1 18 5 1 0

New York 1,538 154 18 11 47 59 5 14

North Carolina 1,029 126 16 5 27 65 1 12

North Dakota 50 12 2 1 3 6 0 0

Ohio 525 153 20 5 59 58 1 10

Oklahoma 434 62 6 8 11 34 0 3

Oregon 365 55 6 4 10 30 0 5

Pennsylvania 1,218 171 24 13 24 92 0 18

Puerto Rico 645 83 6 5 17 47 0 8

Rhode Island 91 13 2 0 4 5 0 2

South Carolina 321 63 6 3 8 41 0 5

South Dakota 87 15 4 1 3 6 0 1

Tennessee 569 121 5 8 16 87 1 4

Texas 2,198 295 63 23 62 122 1 24

Utah 514 54 6 2 14 25 0 7

Vermont 46 11 3 2 0 6 0 0

Virgin Islands 20 4 2 0 0 2 0 0

Virginia 409 73 9 6 4 43 0 11

Washington 843 93 18 3 46 20 2 4

West Virginia 142 36 3 6 3 22 0 2

Wisconsin 561 78 19 1 38 16 1 3

Wyoming 57 11 3 0 1 7 0 0

Tribes - Region 1 4 1 0 0 0 1 0 0

Tribes - Region 5 10 4 3 0 1 0 0 0

Tribes - Region 6 0 0 0 0 0 0 0 0

Tribes - Region 8 6 2 0 1 1 0 0 0

Tribes - Region 9 45 9 6 0 2 1 0 0

Total 32,150 4,139 618 182 1,373 1,568 63 335 1

 The UCMR data are not representative at the state-level.

Number of Small Systems 

(serving ≤10,000 people) Total 

Number of 

Systems

State 1

Number of Very Large Systems 

(serving >100,000 people) Total 

Number of 

Samples

Number of Large Systems 

(serving 10,001 - 100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 16 of 50

Table B8. RDX - UCMR 2 Assessment Monitoring Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 4,249,148 64,214 15,859 850,382 1,612,450 0 1,706,245

Alaska 222,237 6,025 9,791 47,290 23,965 0 135,166

American Samoa 45,000 0 0 0 45,000 0 0

Arizona 4,417,574 32,953 0 999,514 110,587 675,445 2,599,075

Arkansas 1,771,814 31,449 19,189 395,797 638,748 0 686,632

California 32,516,672 101,399 70,338 3,738,533 6,626,442 1,088,908 20,891,052

Colorado 4,395,410 12,154 13,190 312,380 1,020,990 0 3,036,696

Connecticut 2,423,307 6,961 7,784 101,145 929,609 0 1,377,809

Delaware 550,332 14,255 0 54,443 36,130 0 445,504

District of Columbia 783,055 0 0 0 0 0 783,055

Florida 15,964,524 85,230 0 5,601,752 190,650 7,266,168 2,820,724

Georgia 6,323,497 30,214 19,473 555,035 1,594,334 163,688 3,960,753

Guam 136,301 0 0 0 36,300 100,001 0

Hawaii 1,168,403 14,938 0 237,807 128,935 786,723 0

Idaho 598,638 20,705 0 377,881 14,052 0 186,000

Illinois 7,910,559 62,240 31,607 1,237,820 1,377,669 405,228 4,795,996

Indiana 3,833,462 53,832 8,150 1,343,907 460,953 113,400 1,853,220

Iowa 1,669,054 34,873 7,782 635,226 435,492 0 555,682

Kansas 1,903,624 14,044 15,781 288,095 327,403 0 1,258,301

Kentucky 4,050,273 6,419 21,540 145,399 2,190,482 85,697 1,600,737

Louisiana 3,411,211 100,823 8,085 762,163 705,285 663,655 1,171,200

Maine 368,811 10,566 8,770 43,690 192,225 0 113,560

Maryland 4,493,237 9,908 6,123 346,418 348,121 249,600 3,533,067

Massachusetts 7,942,671 43,421 14,171 1,317,567 1,768,248 159,180 4,640,084

Michigan 5,866,881 54,175 12,964 366,966 859,317 283,846 4,289,613

Minnesota 3,092,542 38,944 4,960 1,707,947 406,914 0 933,777

Mississippi 1,418,405 86,727 0 988,496 0 0 343,182

Missouri 3,711,957 49,173 19,101 600,252 449,297 223,971 2,370,164

Montana 376,922 8,734 8,778 72,215 183,824 0 103,371

N. Mariana Islands 72,737 1,081 0 71,656 0 0 0

Navajo Nation 19,080 836 0 18,244 0 0 0

Nebraska 998,770 26,423 0 219,594 37,864 0 714,889

Nevada 1,999,825 13,712 8,323 59,000 73,095 0 1,845,695

New Hampshire 562,737 8,516 10,000 86,706 305,451 0 152,064

New Jersey 7,116,424 60,693 3,400 1,156,623 1,666,422 115,378 4,113,907

New Mexico 1,152,067 16,238 8,256 501,653 172,567 453,353 0

New York 14,764,779 35,519 44,587 1,371,569 1,657,155 1,682,822 9,973,127

North Carolina 5,366,551 37,318 18,964 580,495 1,974,056 108,666 2,647,052

North Dakota 350,292 5,414 2,694 78,529 263,655 0 0

Ohio 8,788,460 64,492 31,964 1,498,349 1,822,242 123,850 5,247,564

Oklahoma 2,491,284 10,318 31,117 241,483 950,915 0 1,257,451

Oregon 2,413,155 13,140 24,170 188,470 830,806 0 1,356,569

Pennsylvania 8,692,491 58,224 57,237 425,487 2,978,041 0 5,173,502

Puerto Rico 5,552,363 20,268 20,177 384,807 1,688,215 0 3,438,896

Rhode Island 911,235 1,812 0 107,302 250,585 0 551,536

South Carolina 2,785,309 14,508 19,828 180,888 1,218,197 0 1,351,888

South Dakota 349,953 10,139 1,592 43,056 167,166 0 128,000

Tennessee 4,625,703 22,345 49,153 428,243 2,499,282 687,096 939,584

Texas 18,832,904 189,890 115,111 1,429,442 3,795,822 1,253,442 12,049,197

Utah 2,403,787 20,075 15,000 274,446 934,364 0 1,159,902

Vermont 196,255 5,245 5,830 0 185,180 0 0

Virgin Islands 67,889 2,550 0 0 65,339 0 0

Virginia 4,635,684 11,756 31,277 98,415 1,285,803 0 3,208,433

Washington 4,265,055 47,921 18,679 1,255,343 756,649 374,556 1,811,906

West Virginia 958,526 8,711 26,897 65,669 527,486 0 329,764

Wisconsin 2,806,236 59,710 8,550 842,048 620,506 205,247 1,070,175

Wyoming 296,668 6,591 0 24,999 265,078 0 0

Tribes - Region 1 41,000 0 0 0 41,000 0 0

Tribes - Region 5 18,788 4,068 0 14,720 0 0 0

Tribes - Region 6 0 0 0 0 0 0 0

Tribes - Region 8 12,160 0 2,020 10,140 0 0 0

Tribes - Region 9 62,055 18,855 0 31,200 12,000 0 0

Total 229,225,740 1,790,743 878,262 34,816,693 49,758,358 17,269,919 124,711,765 1

 The UCMR data are not representative at the state-level.

Pop. Served by Small Systems 

(serving ≤10,000 people)

Pop. Served by Large Systems 

(serving 10,001 - 100,000 people)

Pop. Served by Very Large Systems 

(serving >100,000 people)

State 1

Total 

Population 

Served
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 17 of 50

Table B9. Terbufos Sulfone - UCMR 2 Assessment Monitoring Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 946 120 13 3 36 62 0 6

Alaska 49 9 3 2 2 1 0 1

American Samoa 4 1 0 0 0 1 0 0

Arizona 951 69 13 0 41 5 1 9

Arkansas 289 61 9 4 17 28 0 3

California 6,725 393 32 14 123 152 8 64

Colorado 505 68 5 6 13 34 0 10

Connecticut 329 41 5 1 7 23 0 5

Delaware 106 10 4 0 2 1 0 3

District of Columbia 8 1 0 0 0 0 0 1

Florida 1,152 231 28 0 161 7 23 12

Georgia 570 110 14 5 27 51 1 12

Guam 246 3 0 0 0 2 1 0

Hawaii 315 18 3 0 8 5 2 0

Idaho 257 22 7 0 13 1 0 1

Illinois 839 141 22 5 61 42 3 8

Indiana 399 99 16 2 56 18 1 6

Iowa 233 54 14 1 24 12 0 3

Kansas 224 46 7 4 12 17 0 6

Kentucky 433 107 2 4 10 86 1 4

Louisiana 606 92 25 3 36 21 3 4

Maine 89 19 4 2 3 9 0 1

Maryland 180 38 7 2 13 12 1 3

Massachusetts 965 126 9 3 55 50 1 8

Michigan 393 77 21 2 18 29 2 5

Minnesota 356 91 15 1 64 9 0 2

Mississippi 636 78 30 0 46 0 0 2

Missouri 464 75 16 4 31 19 1 4

Montana 112 13 4 2 1 5 0 1

N. Mariana Islands 69 2 1 0 1 0 0 0

Navajo Nation 12 2 1 0 1 0 0 0

Nebraska 238 22 8 0 10 2 0 2

Nevada 184 15 4 1 4 2 0 4

New Hampshire 155 24 5 1 4 13 0 1

New Jersey 1,055 131 14 1 55 49 1 11

New Mexico 331 32 7 1 18 5 1 0

New York 1,542 154 18 11 47 59 5 14

North Carolina 1,032 126 16 5 27 65 1 12

North Dakota 50 12 2 1 3 6 0 0

Ohio 525 153 20 5 59 58 1 10

Oklahoma 422 62 6 8 11 34 0 3

Oregon 365 55 6 4 10 30 0 5

Pennsylvania 1,218 171 24 13 24 92 0 18

Puerto Rico 655 83 6 5 17 47 0 8

Rhode Island 92 13 2 0 4 5 0 2

South Carolina 321 63 6 3 8 41 0 5

South Dakota 87 15 4 1 3 6 0 1

Tennessee 569 121 5 8 16 87 1 4

Texas 2,200 295 63 23 62 122 1 24

Utah 513 54 6 2 14 25 0 7

Vermont 46 11 3 2 0 6 0 0

Virgin Islands 20 4 2 0 0 2 0 0

Virginia 409 73 9 6 4 43 0 11

Washington 834 93 18 3 46 20 2 4

West Virginia 142 36 3 6 3 22 0 2

Wisconsin 561 78 19 1 38 16 1 3

Wyoming 56 11 3 0 1 7 0 0

Tribes - Region 1 4 1 0 0 0 1 0 0

Tribes - Region 5 10 4 3 0 1 0 0 0

Tribes - Region 6 0 0 0 0 0 0 0 0

Tribes - Region 8 6 2 0 1 1 0 0 0

Tribes - Region 9 45 9 6 0 2 1 0 0

Total 32,149 4,140 618 182 1,374 1,568 63 335 1

 The UCMR data are not representative at the state-level.

State 1

Total 

Number of 

Samples

Total 

Number of 

Systems

Number of Small Systems 

(serving ≤10,000 people)

Number of Large Systems 

(serving 10,001 - 100,000 people)

Number of Very Large Systems 

(serving >100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 18 of 50

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 4,249,148 64,214 15,859 850,382 1,612,450 0 1,706,245

Alaska 234,237 6,025 9,791 59,290 23,965 0 135,166

American Samoa 45,000 0 0 0 45,000 0 0

Arizona 4,417,574 32,953 0 999,514 110,587 675,445 2,599,075

Arkansas 1,771,814 31,449 19,189 395,797 638,748 0 686,632

California 32,516,672 101,399 70,338 3,738,533 6,626,442 1,088,908 20,891,052

Colorado 4,395,410 12,154 13,190 312,380 1,020,990 0 3,036,696

Connecticut 2,423,307 6,961 7,784 101,145 929,609 0 1,377,809

Delaware 550,332 14,255 0 54,443 36,130 0 445,504

District of Columbia 783,055 0 0 0 0 0 783,055

Florida 15,964,524 85,230 0 5,601,752 190,650 7,266,168 2,820,724

Georgia 6,323,497 30,214 19,473 555,035 1,594,334 163,688 3,960,753

Guam 136,301 0 0 0 36,300 100,001 0

Hawaii 1,168,403 14,938 0 237,807 128,935 786,723 0

Idaho 598,638 20,705 0 377,881 14,052 0 186,000

Illinois 7,910,559 62,240 31,607 1,237,820 1,377,669 405,228 4,795,996

Indiana 3,833,462 53,832 8,150 1,343,907 460,953 113,400 1,853,220

Iowa 1,669,054 34,873 7,782 635,226 435,492 0 555,682

Kansas 1,903,624 14,044 15,781 288,095 327,403 0 1,258,301

Kentucky 4,050,273 6,419 21,540 145,399 2,190,482 85,697 1,600,737

Louisiana 3,411,211 100,823 8,085 762,163 705,285 663,655 1,171,200

Maine 368,811 10,566 8,770 43,690 192,225 0 113,560

Maryland 4,493,237 9,908 6,123 346,418 348,121 249,600 3,533,067

Massachusetts 7,942,671 43,421 14,171 1,317,567 1,768,248 159,180 4,640,084

Michigan 5,866,881 54,175 12,964 366,966 859,317 283,846 4,289,613

Minnesota 3,092,542 38,944 4,960 1,707,947 406,914 0 933,777

Mississippi 1,418,405 86,727 0 988,496 0 0 343,182

Missouri 3,711,957 49,173 19,101 600,252 449,297 223,971 2,370,164

Montana 376,922 8,734 8,778 72,215 183,824 0 103,371

N. Mariana Islands 72,737 1,081 0 71,656 0 0 0

Navajo Nation 19,080 836 0 18,244 0 0 0

Nebraska 998,770 26,423 0 219,594 37,864 0 714,889

Nevada 1,999,825 13,712 8,323 59,000 73,095 0 1,845,695

New Hampshire 562,737 8,516 10,000 86,706 305,451 0 152,064

New Jersey 7,116,424 60,693 3,400 1,156,623 1,666,422 115,378 4,113,907

New Mexico 1,152,067 16,238 8,256 501,653 172,567 453,353 0

New York 14,764,779 35,519 44,587 1,371,569 1,657,155 1,682,822 9,973,127

North Carolina 5,366,551 37,318 18,964 580,495 1,974,056 108,666 2,647,052

North Dakota 350,292 5,414 2,694 78,529 263,655 0 0

Ohio 8,788,460 64,492 31,964 1,498,349 1,822,242 123,850 5,247,564

Oklahoma 2,491,284 10,318 31,117 241,483 950,915 0 1,257,451

Oregon 2,413,155 13,140 24,170 188,470 830,806 0 1,356,569

Pennsylvania 8,692,491 58,224 57,237 425,487 2,978,041 0 5,173,502

Puerto Rico 5,552,363 20,268 20,177 384,807 1,688,215 0 3,438,896

Rhode Island 911,235 1,812 0 107,302 250,585 0 551,536

South Carolina 2,785,309 14,508 19,828 180,888 1,218,197 0 1,351,888

South Dakota 349,953 10,139 1,592 43,056 167,166 0 128,000

Tennessee 4,625,703 22,345 49,153 428,243 2,499,282 687,096 939,584

Texas 18,832,904 189,890 115,111 1,429,442 3,795,822 1,253,442 12,049,197

Utah 2,403,787 20,075 15,000 274,446 934,364 0 1,159,902

Vermont 196,255 5,245 5,830 0 185,180 0 0

Virgin Islands 67,889 2,550 0 0 65,339 0 0

Virginia 4,635,684 11,756 31,277 98,415 1,285,803 0 3,208,433

Washington 4,265,055 47,921 18,679 1,255,343 756,649 374,556 1,811,906

West Virginia 958,526 8,711 26,897 65,669 527,486 0 329,764

Wisconsin 2,806,236 59,710 8,550 842,048 620,506 205,247 1,070,175

Wyoming 296,668 6,591 0 24,999 265,078 0 0

Tribes - Region 1 41,000 0 0 0 41,000 0 0

Tribes - Region 5 18,788 4,068 0 14,720 0 0 0

Tribes - Region 6 0 0 0 0 0 0 0

Tribes - Region 8 12,160 0 2,020 10,140 0 0 0

Tribes - Region 9 62,055 18,855 0 31,200 12,000 0 0

Total 229,237,740 1,790,743 878,262 34,828,693 49,758,358 17,269,919 124,711,765 1

 The UCMR data are not representative at the state-level.

Table B9. Terbufos Sulfone - UCMR 2 Assessment Monitoring Data - Number of Systems and Population Served by 

State

State 1

Total 

Population 

Served

Pop. Served by Small Systems 

(serving ≤10,000 people)

Pop. Served by Large Systems 

(serving 10,001 - 100,000 people)

Pop. Served by Very Large Systems 

(serving >100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 19 of 50

Table B10. TNT - UCMR 2 Assessment Monitoring Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 946 120 13 3 36 62 0 6

Alaska 48 8 3 2 1 1 0 1

American Samoa 4 1 0 0 0 1 0 0

Arizona 952 69 13 0 41 5 1 9

Arkansas 290 61 9 4 17 28 0 3

California 6,724 393 32 14 123 152 8 64

Colorado 503 68 5 6 13 34 0 10

Connecticut 329 41 5 1 7 23 0 5

Delaware 106 10 4 0 2 1 0 3

District of Columbia 8 1 0 0 0 0 0 1

Florida 1,155 231 28 0 161 7 23 12

Georgia 570 110 14 5 27 51 1 12

Guam 245 3 0 0 0 2 1 0

Hawaii 313 18 3 0 8 5 2 0

Idaho 256 22 7 0 13 1 0 1

Illinois 839 141 22 5 61 42 3 8

Indiana 399 99 16 2 56 18 1 6

Iowa 234 54 14 1 24 12 0 3

Kansas 226 46 7 4 12 17 0 6

Kentucky 432 107 2 4 10 86 1 4

Louisiana 606 92 25 3 36 21 3 4

Maine 89 19 4 2 3 9 0 1

Maryland 180 38 7 2 13 12 1 3

Massachusetts 965 126 9 3 55 50 1 8

Michigan 393 77 21 2 18 29 2 5

Minnesota 356 91 15 1 64 9 0 2

Mississippi 635 78 30 0 46 0 0 2

Missouri 463 75 16 4 31 19 1 4

Montana 111 13 4 2 1 5 0 1

N. Mariana Islands 68 2 1 0 1 0 0 0

Navajo Nation 12 2 1 0 1 0 0 0

Nebraska 238 22 8 0 10 2 0 2

Nevada 184 15 4 1 4 2 0 4

New Hampshire 155 24 5 1 4 13 0 1

New Jersey 1,058 131 14 1 55 49 1 11

New Mexico 331 32 7 1 18 5 1 0

New York 1,538 154 18 11 47 59 5 14

North Carolina 1,029 126 16 5 27 65 1 12

North Dakota 50 12 2 1 3 6 0 0

Ohio 525 153 20 5 59 58 1 10

Oklahoma 434 62 6 8 11 34 0 3

Oregon 365 55 6 4 10 30 0 5

Pennsylvania 1,218 171 24 13 24 92 0 18

Puerto Rico 645 83 6 5 17 47 0 8

Rhode Island 91 13 2 0 4 5 0 2

South Carolina 321 63 6 3 8 41 0 5

South Dakota 87 15 4 1 3 6 0 1

Tennessee 569 121 5 8 16 87 1 4

Texas 2,199 295 63 23 62 122 1 24

Utah 514 54 6 2 14 25 0 7

Vermont 46 11 3 2 0 6 0 0

Virgin Islands 20 4 2 0 0 2 0 0

Virginia 409 73 9 6 4 43 0 11

Washington 843 93 18 3 46 20 2 4

West Virginia 142 36 3 6 3 22 0 2

Wisconsin 561 78 19 1 38 16 1 3

Wyoming 57 11 3 0 1 7 0 0

Tribes - Region 1 4 1 0 0 0 1 0 0

Tribes - Region 5 10 4 3 0 1 0 0 0

Tribes - Region 6 0 0 0 0 0 0 0 0

Tribes - Region 8 6 2 0 1 1 0 0 0

Tribes - Region 9 45 9 6 0 2 1 0 0

Total 32,151 4,139 618 182 1,373 1,568 63 335 1

 The UCMR data are not representative at the state-level.

Number of Very Large Systems 

(serving >100,000 people)

State 1

Total 

Number of 

Samples

Total 

Number of 

Systems

Number of Small Systems 

(serving ≤10,000 people)

Number of Large Systems 

(serving 10,001 - 100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 20 of 50

Table B10. TNT - UCMR 2 Assessment Monitoring Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 4,249,148 64,214 15,859 850,382 1,612,450 0 1,706,245

Alaska 222,237 6,025 9,791 47,290 23,965 0 135,166

American Samoa 45,000 0 0 0 45,000 0 0

Arizona 4,417,574 32,953 0 999,514 110,587 675,445 2,599,075

Arkansas 1,771,814 31,449 19,189 395,797 638,748 0 686,632

California 32,516,672 101,399 70,338 3,738,533 6,626,442 1,088,908 20,891,052

Colorado 4,395,410 12,154 13,190 312,380 1,020,990 0 3,036,696

Connecticut 2,423,307 6,961 7,784 101,145 929,609 0 1,377,809

Delaware 550,332 14,255 0 54,443 36,130 0 445,504

District of Columbia 783,055 0 0 0 0 0 783,055

Florida 15,964,524 85,230 0 5,601,752 190,650 7,266,168 2,820,724

Georgia 6,323,497 30,214 19,473 555,035 1,594,334 163,688 3,960,753

Guam 136,301 0 0 0 36,300 100,001 0

Hawaii 1,168,403 14,938 0 237,807 128,935 786,723 0

Idaho 598,638 20,705 0 377,881 14,052 0 186,000

Illinois 7,910,559 62,240 31,607 1,237,820 1,377,669 405,228 4,795,996

Indiana 3,833,462 53,832 8,150 1,343,907 460,953 113,400 1,853,220

Iowa 1,669,054 34,873 7,782 635,226 435,492 0 555,682

Kansas 1,903,624 14,044 15,781 288,095 327,403 0 1,258,301

Kentucky 4,050,273 6,419 21,540 145,399 2,190,482 85,697 1,600,737

Louisiana 3,411,211 100,823 8,085 762,163 705,285 663,655 1,171,200

Maine 368,811 10,566 8,770 43,690 192,225 0 113,560

Maryland 4,493,237 9,908 6,123 346,418 348,121 249,600 3,533,067

Massachusetts 7,942,671 43,421 14,171 1,317,567 1,768,248 159,180 4,640,084

Michigan 5,866,881 54,175 12,964 366,966 859,317 283,846 4,289,613

Minnesota 3,092,542 38,944 4,960 1,707,947 406,914 0 933,777

Mississippi 1,418,405 86,727 0 988,496 0 0 343,182

Missouri 3,711,957 49,173 19,101 600,252 449,297 223,971 2,370,164

Montana 376,922 8,734 8,778 72,215 183,824 0 103,371

N. Mariana Islands 72,737 1,081 0 71,656 0 0 0

Navajo Nation 19,080 836 0 18,244 0 0 0

Nebraska 998,770 26,423 0 219,594 37,864 0 714,889

Nevada 1,999,825 13,712 8,323 59,000 73,095 0 1,845,695

New Hampshire 562,737 8,516 10,000 86,706 305,451 0 152,064

New Jersey 7,116,424 60,693 3,400 1,156,623 1,666,422 115,378 4,113,907

New Mexico 1,152,067 16,238 8,256 501,653 172,567 453,353 0

New York 14,764,779 35,519 44,587 1,371,569 1,657,155 1,682,822 9,973,127

North Carolina 5,366,551 37,318 18,964 580,495 1,974,056 108,666 2,647,052

North Dakota 350,292 5,414 2,694 78,529 263,655 0 0

Ohio 8,788,460 64,492 31,964 1,498,349 1,822,242 123,850 5,247,564

Oklahoma 2,491,284 10,318 31,117 241,483 950,915 0 1,257,451

Oregon 2,413,155 13,140 24,170 188,470 830,806 0 1,356,569

Pennsylvania 8,692,491 58,224 57,237 425,487 2,978,041 0 5,173,502

Puerto Rico 5,552,363 20,268 20,177 384,807 1,688,215 0 3,438,896

Rhode Island 911,235 1,812 0 107,302 250,585 0 551,536

South Carolina 2,785,309 14,508 19,828 180,888 1,218,197 0 1,351,888

South Dakota 349,953 10,139 1,592 43,056 167,166 0 128,000

Tennessee 4,625,703 22,345 49,153 428,243 2,499,282 687,096 939,584

Texas 18,832,904 189,890 115,111 1,429,442 3,795,822 1,253,442 12,049,197

Utah 2,403,787 20,075 15,000 274,446 934,364 0 1,159,902

Vermont 196,255 5,245 5,830 0 185,180 0 0

Virgin Islands 67,889 2,550 0 0 65,339 0 0

Virginia 4,635,684 11,756 31,277 98,415 1,285,803 0 3,208,433

Washington 4,265,055 47,921 18,679 1,255,343 756,649 374,556 1,811,906

West Virginia 958,526 8,711 26,897 65,669 527,486 0 329,764

Wisconsin 2,806,236 59,710 8,550 842,048 620,506 205,247 1,070,175

Wyoming 296,668 6,591 0 24,999 265,078 0 0

Tribes - Region 1 41,000 0 0 0 41,000 0 0

Tribes - Region 5 18,788 4,068 0 14,720 0 0 0

Tribes - Region 6 0 0 0 0 0 0 0

Tribes - Region 8 12,160 0 2,020 10,140 0 0 0

Tribes - Region 9 62,055 18,855 0 31,200 12,000 0 0

Total 229,225,740 1,790,743 878,262 34,816,693 49,758,358 17,269,919 124,711,765 1

 The UCMR data are not representative at the state-level.

State 1

Total 

Population 

Served

Pop. Served by Small Systems 

(serving ≤10,000 people)

Pop. Served by Large Systems 

(serving 10,001 - 100,000 people)

Pop. Served by Very Large Systems 

(serving >100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 21 of 50

Table B11. Acetochlor - UCMR 2 Screening Survey Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 147 20 4 2 3 5 0 6

Alaska 58 9 1 7 0 0 0 1

American Samoa 0 0 0 0 0 0 0 0

Arizona 382 19 4 2 3 0 1 9

Arkansas 68 13 3 3 2 2 0 3

California 3,347 154 13 28 19 22 8 64

Colorado 159 26 3 9 1 3 0 10

Connecticut 84 12 3 1 1 2 0 5

Delaware 83 5 1 0 1 0 0 3

District of Columbia 8 1 0 0 0 0 0 1

Florida 433 79 11 1 31 1 23 12

Georgia 170 31 6 5 2 5 1 12

Guam 219 1 0 0 0 0 1 0

Hawaii 140 4 1 0 1 0 2 0

Idaho 67 9 3 3 2 0 0 1

Illinois 270 35 7 5 4 8 3 8

Indiana 109 21 5 2 5 2 1 6

Iowa 82 15 5 2 3 2 0 3

Kansas 76 16 3 5 1 1 0 6

Kentucky 83 17 0 4 0 8 1 4

Louisiana 212 22 8 2 3 2 3 4

Maine 22 6 2 2 0 1 0 1

Maryland 60 13 3 3 2 1 1 3

Massachusetts 141 24 4 2 4 5 1 8

Michigan 146 23 9 2 2 3 2 5

Minnesota 59 18 6 1 7 2 0 2

Mississippi 82 15 10 0 3 0 0 2

Missouri 96 20 6 4 3 2 1 4

Montana 24 7 2 4 0 0 0 1

N. Mariana Islands 0 0 0 0 0 0 0 0

Navajo Nation 14 3 2 0 1 0 0 0

Nebraska 45 7 3 1 1 0 0 2

Nevada 98 8 2 1 0 1 0 4

New Hampshire 17 6 3 1 0 1 0 1

New Jersey 257 26 6 0 4 4 1 11

New Mexico 110 8 3 2 2 0 1 0

New York 857 53 8 14 6 6 5 14

North Carolina 210 35 7 5 3 7 1 12

North Dakota 14 4 1 2 0 1 0 0

Ohio 152 36 7 5 7 6 1 10

Oklahoma 83 19 3 9 1 3 0 3

Oregon 84 17 3 6 0 3 0 5

Pennsylvania 333 51 10 14 0 9 0 18

Puerto Rico 275 27 2 10 2 5 0 8

Rhode Island 18 4 1 0 0 1 0 2

South Carolina 70 16 3 3 1 4 0 5

South Dakota 32 9 2 5 0 1 0 1

Tennessee 114 23 1 7 2 8 1 4

Texas 779 96 23 27 6 15 1 24

Utah 142 16 2 3 1 3 0 7

Vermont 18 5 1 3 0 1 0 0

Virgin Islands 2 1 1 0 0 0 0 0

Virginia 158 27 4 7 0 5 0 11

Washington 253 29 8 4 8 3 2 4

West Virginia 46 12 1 7 0 2 0 2

Wisconsin 149 17 8 0 3 2 1 3

Wyoming 16 4 0 3 0 1 0 0

Tribes - Region 1 0 0 0 0 0 0 0 0

Tribes - Region 5 0 0 0 0 0 0 0 0

Tribes - Region 6 4 2 2 0 0 0 0 0

Tribes - Region 8 0 0 0 0 0 0 0 0

Tribes - Region 9 16 2 0 2 0 0 0 0

Total 11,193 1,198 240 240 151 169 63 335 1

 The UCMR data are not representative at the state-level.

Number of Very Large Systems 

(serving >100,000 people)

State 1

Total 

Number of 

Samples

Total 

Number of 

Systems

Number of Small Systems 

(serving ≤10,000 people)

Number of Large Systems 

(serving 10,001 - 100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 22 of 50

Table B11. Acetochlor - UCMR 2 Screening Survey Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 2,040,600 17,259 9,693 103,109 204,295 0 1,706,245

Alaska 143,305 90 8,049 0 0 0 135,166

American Samoa 0 0 0 0 0 0 0

Arizona 3,403,868 14,319 1,729 113,300 0 675,445 2,599,075

Arkansas 845,459 11,365 8,930 85,674 52,858 0 686,632

California 24,372,007 29,816 49,813 1,008,796 1,303,622 1,088,908 20,891,052

Colorado 3,219,993 8,226 15,710 31,000 128,361 0 3,036,696

Connecticut 1,497,295 1,004 6,620 17,500 94,362 0 1,377,809

Delaware 484,765 4,383 0 34,878 0 0 445,504

District of Columbia 783,055 0 0 0 0 0 783,055

Florida 11,889,692 31,802 7,075 1,732,771 31,152 7,266,168 2,820,724

Georgia 4,397,366 9,885 12,463 39,543 211,034 163,688 3,960,753

Guam 100,001 0 0 0 0 100,001 0

Hawaii 854,836 4,958 0 63,155 0 786,723 0

Idaho 280,917 5,329 1,237 88,351 0 0 186,000

Illinois 5,680,520 22,938 20,358 71,451 364,550 405,228 4,795,996

Indiana 2,277,440 14,331 9,489 216,877 70,123 113,400 1,853,220

Iowa 805,109 14,756 7,369 146,216 81,086 0 555,682

Kansas 1,331,673 6,004 14,995 41,348 11,025 0 1,258,301

Kentucky 1,962,150 0 17,056 0 258,661 85,697 1,600,737

Louisiana 2,049,851 22,928 7,429 115,495 69,144 663,655 1,171,200

Maine 132,909 724 7,600 0 11,025 0 113,560

Maryland 3,874,592 6,534 7,390 64,801 13,200 249,600 3,533,067

Massachusetts 5,202,826 10,300 12,914 130,449 249,899 159,180 4,640,084

Michigan 4,826,722 12,746 12,269 97,711 130,537 283,846 4,289,613

Minnesota 1,400,744 10,862 7,501 300,404 148,200 0 933,777

Mississippi 424,022 31,538 0 49,302 0 0 343,182

Missouri 2,793,981 11,698 13,341 97,715 77,092 223,971 2,370,164

Montana 112,643 3,104 6,168 0 0 0 103,371

N. Mariana Islands 0 0 0 0 0 0 0

Navajo Nation 21,873 3,629 0 18,244 0 0 0

Nebraska 743,335 4,946 2,500 21,000 0 0 714,889

Nevada 1,908,764 6,832 237 0 56,000 0 1,845,695

New Hampshire 165,859 950 1,595 0 11,250 0 152,064

New Jersey 4,449,920 10,749 0 91,759 118,127 115,378 4,113,907

New Mexico 568,968 7,769 2,846 105,000 0 453,353 0

New York 12,173,772 8,634 35,158 248,594 225,437 1,682,822 9,973,127

North Carolina 3,220,020 15,311 26,493 111,438 311,061 108,666 2,647,052

North Dakota 92,952 1,099 1,254 0 90,599 0 0

Ohio 5,968,446 21,415 12,060 300,293 263,264 123,850 5,247,564

Oklahoma 1,432,777 6,402 25,003 15,435 128,486 0 1,257,451

Oregon 1,505,465 7,740 18,036 0 123,120 0 1,356,569

Pennsylvania 5,612,428 14,708 33,537 0 390,681 0 5,173,502

Puerto Rico 3,794,459 4,955 17,083 112,793 220,732 0 3,438,896

Rhode Island 613,600 355 0 0 61,709 0 551,536

South Carolina 1,604,882 8,549 10,201 53,122 181,122 0 1,351,888

South Dakota 152,210 811 3,162 0 20,237 0 128,000

Tennessee 2,104,138 8,587 31,013 66,568 371,290 687,096 939,584

Texas 14,372,970 60,963 89,693 228,445 691,230 1,253,442 12,049,197

Utah 1,362,703 8,500 9,345 24,000 160,956 0 1,159,902

Vermont 63,618 298 11,570 0 51,750 0 0

Virgin Islands 50 50 0 0 0 0 0

Virginia 3,377,005 3,451 21,232 0 143,889 0 3,208,433

Washington 2,706,556 15,667 6,360 404,649 93,417 374,556 1,811,906

West Virginia 434,635 424 26,216 0 78,231 0 329,764

Wisconsin 1,507,678 17,221 0 133,000 82,035 205,247 1,070,175

Wyoming 68,027 0 8,043 0 59,984 0 0

Tribes - Region 1 0 0 0 0 0 0 0

Tribes - Region 5 0 0 0 0 0 0 0

Tribes - Region 6 1,450 1,450 0 0 0 0 0

Tribes - Region 8 0 0 0 0 0 0 0

Tribes - Region 9 2,722 0 2,722 0 0 0 0

Total 157,219,620 548,364 660,557 6,584,184 7,444,830 17,269,919 124,711,765 1

 The UCMR data are not representative at the state-level.

State 1

Total 

Population 

Served

Pop. Served by Small Systems 

(serving ≤10,000 people)

Pop. Served by Large Systems 

(serving 10,001 - 100,000 people)

Pop. Served by Very Large Systems 

(serving >100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 23 of 50

Table B12. Acetochlor ESA - UCMR 2 Screening Survey Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 147 20 4 2 3 5 0 6

Alaska 58 9 1 7 0 0 0 1

American Samoa 0 0 0 0 0 0 0 0

Arizona 382 19 4 2 3 0 1 9

Arkansas 68 13 3 3 2 2 0 3

California 3,351 154 13 28 19 22 8 64

Colorado 158 26 3 9 1 3 0 10

Connecticut 83 12 3 1 1 2 0 5

Delaware 83 5 1 0 1 0 0 3

District of Columbia 8 1 0 0 0 0 0 1

Florida 432 79 11 1 31 1 23 12

Georgia 169 31 6 5 2 5 1 12

Guam 220 1 0 0 0 0 1 0

Hawaii 140 4 1 0 1 0 2 0

Idaho 67 9 3 3 2 0 0 1

Illinois 270 35 7 5 4 8 3 8

Indiana 109 21 5 2 5 2 1 6

Iowa 82 15 5 2 3 2 0 3

Kansas 76 16 3 5 1 1 0 6

Kentucky 83 17 0 4 0 8 1 4

Louisiana 209 22 8 2 3 2 3 4

Maine 22 6 2 2 0 1 0 1

Maryland 60 13 3 3 2 1 1 3

Massachusetts 135 24 4 2 4 5 1 8

Michigan 145 23 9 2 2 3 2 5

Minnesota 59 18 6 1 7 2 0 2

Mississippi 82 15 10 0 3 0 0 2

Missouri 95 20 6 4 3 2 1 4

Montana 24 7 2 4 0 0 0 1

N. Mariana Islands 0 0 0 0 0 0 0 0

Navajo Nation 14 3 2 0 1 0 0 0

Nebraska 45 7 3 1 1 0 0 2

Nevada 98 8 2 1 0 1 0 4

New Hampshire 17 6 3 1 0 1 0 1

New Jersey 257 26 6 0 4 4 1 11

New Mexico 110 8 3 2 2 0 1 0

New York 848 53 8 14 6 6 5 14

North Carolina 209 35 7 5 3 7 1 12

North Dakota 14 4 1 2 0 1 0 0

Ohio 152 36 7 5 7 6 1 10

Oklahoma 83 19 3 9 1 3 0 3

Oregon 84 17 3 6 0 3 0 5

Pennsylvania 334 51 10 14 0 9 0 18

Puerto Rico 275 27 2 10 2 5 0 8

Rhode Island 18 4 1 0 0 1 0 2

South Carolina 70 16 3 3 1 4 0 5

South Dakota 32 9 2 5 0 1 0 1

Tennessee 114 23 1 7 2 8 1 4

Texas 776 96 23 27 6 15 1 24

Utah 142 16 2 3 1 3 0 7

Vermont 17 5 1 3 0 1 0 0

Virgin Islands 2 1 1 0 0 0 0 0

Virginia 158 27 4 7 0 5 0 11

Washington 241 29 8 4 8 3 2 4

West Virginia 46 12 1 7 0 2 0 2

Wisconsin 149 17 8 0 3 2 1 3

Wyoming 16 4 0 3 0 1 0 0

Tribes - Region 1 0 0 0 0 0 0 0 0

Tribes - Region 5 0 0 0 0 0 0 0 0

Tribes - Region 6 3 2 2 0 0 0 0 0

Tribes - Region 8 0 0 0 0 0 0 0 0

Tribes - Region 9 16 2 0 2 0 0 0 0

Total 11,157 1,198 240 240 151 169 63 335 1

 The UCMR data are not representative at the state-level.

Number of Very Large Systems 

(serving >100,000 people)

State 1

Total 

Number of 

Samples

Total 

Number of 

Systems

Number of Small Systems 

(serving ≤10,000 people)

Number of Large Systems 

(serving 10,001 - 100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 24 of 50

Table B12. Acetochlor ESA - UCMR 2 Screening Survey Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 2,040,600 17,259 9,693 103,109 204,295 0 1,706,245

Alaska 143,305 90 8,049 0 0 0 135,166

American Samoa 0 0 0 0 0 0 0

Arizona 3,403,868 14,319 1,729 113,300 0 675,445 2,599,075

Arkansas 845,459 11,365 8,930 85,674 52,858 0 686,632

California 24,372,007 29,816 49,813 1,008,796 1,303,622 1,088,908 20,891,052

Colorado 3,219,993 8,226 15,710 31,000 128,361 0 3,036,696

Connecticut 1,497,295 1,004 6,620 17,500 94,362 0 1,377,809

Delaware 484,765 4,383 0 34,878 0 0 445,504

District of Columbia 783,055 0 0 0 0 0 783,055

Florida 11,889,692 31,802 7,075 1,732,771 31,152 7,266,168 2,820,724

Georgia 4,397,366 9,885 12,463 39,543 211,034 163,688 3,960,753

Guam 100,001 0 0 0 0 100,001 0

Hawaii 854,836 4,958 0 63,155 0 786,723 0

Idaho 280,917 5,329 1,237 88,351 0 0 186,000

Illinois 5,680,520 22,938 20,358 71,451 364,550 405,228 4,795,996

Indiana 2,277,440 14,331 9,489 216,877 70,123 113,400 1,853,220

Iowa 805,109 14,756 7,369 146,216 81,086 0 555,682

Kansas 1,331,673 6,004 14,995 41,348 11,025 0 1,258,301

Kentucky 1,962,150 0 17,056 0 258,661 85,697 1,600,737

Louisiana 2,049,851 22,928 7,429 115,495 69,144 663,655 1,171,200

Maine 132,909 724 7,600 0 11,025 0 113,560

Maryland 3,874,592 6,534 7,390 64,801 13,200 249,600 3,533,067

Massachusetts 5,202,826 10,300 12,914 130,449 249,899 159,180 4,640,084

Michigan 4,826,722 12,746 12,269 97,711 130,537 283,846 4,289,613

Minnesota 1,400,744 10,862 7,501 300,404 148,200 0 933,777

Mississippi 424,022 31,538 0 49,302 0 0 343,182

Missouri 2,793,981 11,698 13,341 97,715 77,092 223,971 2,370,164

Montana 112,643 3,104 6,168 0 0 0 103,371

N. Mariana Islands 0 0 0 0 0 0 0

Navajo Nation 21,873 3,629 0 18,244 0 0 0

Nebraska 743,335 4,946 2,500 21,000 0 0 714,889

Nevada 1,908,764 6,832 237 0 56,000 0 1,845,695

New Hampshire 165,859 950 1,595 0 11,250 0 152,064

New Jersey 4,449,920 10,749 0 91,759 118,127 115,378 4,113,907

New Mexico 568,968 7,769 2,846 105,000 0 453,353 0

New York 12,173,772 8,634 35,158 248,594 225,437 1,682,822 9,973,127

North Carolina 3,220,020 15,311 26,493 111,438 311,061 108,666 2,647,052

North Dakota 92,952 1,099 1,254 0 90,599 0 0

Ohio 5,968,446 21,415 12,060 300,293 263,264 123,850 5,247,564

Oklahoma 1,432,777 6,402 25,003 15,435 128,486 0 1,257,451

Oregon 1,505,465 7,740 18,036 0 123,120 0 1,356,569

Pennsylvania 5,612,428 14,708 33,537 0 390,681 0 5,173,502

Puerto Rico 3,794,459 4,955 17,083 112,793 220,732 0 3,438,896

Rhode Island 613,600 355 0 0 61,709 0 551,536

South Carolina 1,604,882 8,549 10,201 53,122 181,122 0 1,351,888

South Dakota 152,210 811 3,162 0 20,237 0 128,000

Tennessee 2,104,138 8,587 31,013 66,568 371,290 687,096 939,584

Texas 14,372,970 60,963 89,693 228,445 691,230 1,253,442 12,049,197

Utah 1,362,703 8,500 9,345 24,000 160,956 0 1,159,902

Vermont 63,618 298 11,570 0 51,750 0 0

Virgin Islands 50 50 0 0 0 0 0

Virginia 3,377,005 3,451 21,232 0 143,889 0 3,208,433

Washington 2,706,556 15,667 6,360 404,649 93,417 374,556 1,811,906

West Virginia 434,635 424 26,216 0 78,231 0 329,764

Wisconsin 1,507,678 17,221 0 133,000 82,035 205,247 1,070,175

Wyoming 68,027 0 8,043 0 59,984 0 0

Tribes - Region 1 0 0 0 0 0 0 0

Tribes - Region 5 0 0 0 0 0 0 0

Tribes - Region 6 1,450 1,450 0 0 0 0 0

Tribes - Region 8 0 0 0 0 0 0 0

Tribes - Region 9 2,722 0 2,722 0 0 0 0

Total 157,219,620 548,364 660,557 6,584,184 7,444,830 17,269,919 124,711,765 1

 The UCMR data are not representative at the state-level.

State 1

Total 

Population 

Served

Pop. Served by Small Systems 

(serving ≤10,000 people)

Pop. Served by Large Systems 

(serving 10,001 - 100,000 people)

Pop. Served by Very Large Systems 

(serving >100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 25 of 50

Table B13. Acetochlor OA - UCMR 2 Screening Survey Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 147 20 4 2 3 5 0 6

Alaska 58 9 1 7 0 0 0 1

American Samoa 0 0 0 0 0 0 0 0

Arizona 382 19 4 2 3 0 1 9

Arkansas 68 13 3 3 2 2 0 3

California 3,351 154 13 28 19 22 8 64

Colorado 158 26 3 9 1 3 0 10

Connecticut 83 12 3 1 1 2 0 5

Delaware 83 5 1 0 1 0 0 3

District of Columbia 8 1 0 0 0 0 0 1

Florida 432 79 11 1 31 1 23 12

Georgia 169 31 6 5 2 5 1 12

Guam 220 1 0 0 0 0 1 0

Hawaii 140 4 1 0 1 0 2 0

Idaho 67 9 3 3 2 0 0 1

Illinois 270 35 7 5 4 8 3 8

Indiana 109 21 5 2 5 2 1 6

Iowa 82 15 5 2 3 2 0 3

Kansas 76 16 3 5 1 1 0 6

Kentucky 83 17 0 4 0 8 1 4

Louisiana 209 22 8 2 3 2 3 4

Maine 22 6 2 2 0 1 0 1

Maryland 60 13 3 3 2 1 1 3

Massachusetts 135 24 4 2 4 5 1 8

Michigan 145 23 9 2 2 3 2 5

Minnesota 59 18 6 1 7 2 0 2

Mississippi 82 15 10 0 3 0 0 2

Missouri 95 20 6 4 3 2 1 4

Montana 24 7 2 4 0 0 0 1

N. Mariana Islands 0 0 0 0 0 0 0 0

Navajo Nation 14 3 2 0 1 0 0 0

Nebraska 45 7 3 1 1 0 0 2

Nevada 98 8 2 1 0 1 0 4

New Hampshire 17 6 3 1 0 1 0 1

New Jersey 257 26 6 0 4 4 1 11

New Mexico 110 8 3 2 2 0 1 0

New York 848 53 8 14 6 6 5 14

North Carolina 209 35 7 5 3 7 1 12

North Dakota 14 4 1 2 0 1 0 0

Ohio 152 36 7 5 7 6 1 10

Oklahoma 83 19 3 9 1 3 0 3

Oregon 84 17 3 6 0 3 0 5

Pennsylvania 334 51 10 14 0 9 0 18

Puerto Rico 275 27 2 10 2 5 0 8

Rhode Island 18 4 1 0 0 1 0 2

South Carolina 70 16 3 3 1 4 0 5

South Dakota 32 9 2 5 0 1 0 1

Tennessee 114 23 1 7 2 8 1 4

Texas 776 96 23 27 6 15 1 24

Utah 142 16 2 3 1 3 0 7

Vermont 17 5 1 3 0 1 0 0

Virgin Islands 2 1 1 0 0 0 0 0

Virginia 158 27 4 7 0 5 0 11

Washington 241 29 8 4 8 3 2 4

West Virginia 46 12 1 7 0 2 0 2

Wisconsin 149 17 8 0 3 2 1 3

Wyoming 16 4 0 3 0 1 0 0

Tribes - Region 1 0 0 0 0 0 0 0 0

Tribes - Region 5 0 0 0 0 0 0 0 0

Tribes - Region 6 3 2 2 0 0 0 0 0

Tribes - Region 8 0 0 0 0 0 0 0 0

Tribes - Region 9 16 2 0 2 0 0 0 0

Total 11,157 1,198 240 240 151 169 63 335 1

 The UCMR data are not representative at the state-level.

Number of Very Large Systems 

(serving >100,000 people)

State 1

Total 

Number of 

Samples

Total 

Number of 

Systems

Number of Small Systems 

(serving ≤10,000 people)

Number of Large Systems 

(serving 10,001 - 100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 26 of 50

Table B13. Acetochlor OA - UCMR 2 Screening Survey Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 2,040,600 17,259 9,693 103,109 204,295 0 1,706,245

Alaska 143,305 90 8,049 0 0 0 135,166

American Samoa 0 0 0 0 0 0 0

Arizona 3,403,868 14,319 1,729 113,300 0 675,445 2,599,075

Arkansas 845,459 11,365 8,930 85,674 52,858 0 686,632

California 24,372,007 29,816 49,813 1,008,796 1,303,622 1,088,908 20,891,052

Colorado 3,219,993 8,226 15,710 31,000 128,361 0 3,036,696

Connecticut 1,497,295 1,004 6,620 17,500 94,362 0 1,377,809

Delaware 484,765 4,383 0 34,878 0 0 445,504

District of Columbia 783,055 0 0 0 0 0 783,055

Florida 11,889,692 31,802 7,075 1,732,771 31,152 7,266,168 2,820,724

Georgia 4,397,366 9,885 12,463 39,543 211,034 163,688 3,960,753

Guam 100,001 0 0 0 0 100,001 0

Hawaii 854,836 4,958 0 63,155 0 786,723 0

Idaho 280,917 5,329 1,237 88,351 0 0 186,000

Illinois 5,680,520 22,938 20,358 71,451 364,550 405,228 4,795,996

Indiana 2,277,440 14,331 9,489 216,877 70,123 113,400 1,853,220

Iowa 805,109 14,756 7,369 146,216 81,086 0 555,682

Kansas 1,331,673 6,004 14,995 41,348 11,025 0 1,258,301

Kentucky 1,962,150 0 17,056 0 258,661 85,697 1,600,737

Louisiana 2,049,851 22,928 7,429 115,495 69,144 663,655 1,171,200

Maine 132,909 724 7,600 0 11,025 0 113,560

Maryland 3,874,592 6,534 7,390 64,801 13,200 249,600 3,533,067

Massachusetts 5,202,826 10,300 12,914 130,449 249,899 159,180 4,640,084

Michigan 4,826,722 12,746 12,269 97,711 130,537 283,846 4,289,613

Minnesota 1,400,744 10,862 7,501 300,404 148,200 0 933,777

Mississippi 424,022 31,538 0 49,302 0 0 343,182

Missouri 2,793,981 11,698 13,341 97,715 77,092 223,971 2,370,164

Montana 112,643 3,104 6,168 0 0 0 103,371

N. Mariana Islands 0 0 0 0 0 0 0

Navajo Nation 21,873 3,629 0 18,244 0 0 0

Nebraska 743,335 4,946 2,500 21,000 0 0 714,889

Nevada 1,908,764 6,832 237 0 56,000 0 1,845,695

New Hampshire 165,859 950 1,595 0 11,250 0 152,064

New Jersey 4,449,920 10,749 0 91,759 118,127 115,378 4,113,907

New Mexico 568,968 7,769 2,846 105,000 0 453,353 0

New York 12,173,772 8,634 35,158 248,594 225,437 1,682,822 9,973,127

North Carolina 3,220,020 15,311 26,493 111,438 311,061 108,666 2,647,052

North Dakota 92,952 1,099 1,254 0 90,599 0 0

Ohio 5,968,446 21,415 12,060 300,293 263,264 123,850 5,247,564

Oklahoma 1,432,777 6,402 25,003 15,435 128,486 0 1,257,451

Oregon 1,505,465 7,740 18,036 0 123,120 0 1,356,569

Pennsylvania 5,612,428 14,708 33,537 0 390,681 0 5,173,502

Puerto Rico 3,794,459 4,955 17,083 112,793 220,732 0 3,438,896

Rhode Island 613,600 355 0 0 61,709 0 551,536

South Carolina 1,604,882 8,549 10,201 53,122 181,122 0 1,351,888

South Dakota 152,210 811 3,162 0 20,237 0 128,000

Tennessee 2,104,138 8,587 31,013 66,568 371,290 687,096 939,584

Texas 14,372,970 60,963 89,693 228,445 691,230 1,253,442 12,049,197

Utah 1,362,703 8,500 9,345 24,000 160,956 0 1,159,902

Vermont 63,618 298 11,570 0 51,750 0 0

Virgin Islands 50 50 0 0 0 0 0

Virginia 3,377,005 3,451 21,232 0 143,889 0 3,208,433

Washington 2,706,556 15,667 6,360 404,649 93,417 374,556 1,811,906

West Virginia 434,635 424 26,216 0 78,231 0 329,764

Wisconsin 1,507,678 17,221 0 133,000 82,035 205,247 1,070,175

Wyoming 68,027 0 8,043 0 59,984 0 0

Tribes - Region 1 0 0 0 0 0 0 0

Tribes - Region 5 0 0 0 0 0 0 0

Tribes - Region 6 1,450 1,450 0 0 0 0 0

Tribes - Region 8 0 0 0 0 0 0 0

Tribes - Region 9 2,722 0 2,722 0 0 0 0

Total 157,219,620 548,364 660,557 6,584,184 7,444,830 17,269,919 124,711,765 1

 The UCMR data are not representative at the state-level.

State 1

Total 

Population 

Served

Pop. Served by Small Systems 

(serving ≤10,000 people)

Pop. Served by Large Systems 

(serving 10,001 - 100,000 people)

Pop. Served by Very Large Systems 

(serving >100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 27 of 50

Table B14. Alachlor - UCMR 2 Screening Survey Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 147 20 4 2 3 5 0 6

Alaska 58 9 1 7 0 0 0 1

American Samoa 0 0 0 0 0 0 0 0

Arizona 382 19 4 2 3 0 1 9

Arkansas 68 13 3 3 2 2 0 3

California 3,347 154 13 28 19 22 8 64

Colorado 159 26 3 9 1 3 0 10

Connecticut 84 12 3 1 1 2 0 5

Delaware 83 5 1 0 1 0 0 3

District of Columbia 8 1 0 0 0 0 0 1

Florida 433 79 11 1 31 1 23 12

Georgia 170 31 6 5 2 5 1 12

Guam 219 1 0 0 0 0 1 0

Hawaii 140 4 1 0 1 0 2 0

Idaho 67 9 3 3 2 0 0 1

Illinois 270 35 7 5 4 8 3 8

Indiana 109 21 5 2 5 2 1 6

Iowa 82 15 5 2 3 2 0 3

Kansas 76 16 3 5 1 1 0 6

Kentucky 83 17 0 4 0 8 1 4

Louisiana 212 22 8 2 3 2 3 4

Maine 22 6 2 2 0 1 0 1

Maryland 60 13 3 3 2 1 1 3

Massachusetts 141 24 4 2 4 5 1 8

Michigan 146 23 9 2 2 3 2 5

Minnesota 59 18 6 1 7 2 0 2

Mississippi 82 15 10 0 3 0 0 2

Missouri 96 20 6 4 3 2 1 4

Montana 24 7 2 4 0 0 0 1

N. Mariana Islands 0 0 0 0 0 0 0 0

Navajo Nation 14 3 2 0 1 0 0 0

Nebraska 45 7 3 1 1 0 0 2

Nevada 98 8 2 1 0 1 0 4

New Hampshire 17 6 3 1 0 1 0 1

New Jersey 257 26 6 0 4 4 1 11

New Mexico 110 8 3 2 2 0 1 0

New York 857 53 8 14 6 6 5 14

North Carolina 210 35 7 5 3 7 1 12

North Dakota 14 4 1 2 0 1 0 0

Ohio 152 36 7 5 7 6 1 10

Oklahoma 83 19 3 9 1 3 0 3

Oregon 84 17 3 6 0 3 0 5

Pennsylvania 333 51 10 14 0 9 0 18

Puerto Rico 275 27 2 10 2 5 0 8

Rhode Island 18 4 1 0 0 1 0 2

South Carolina 70 16 3 3 1 4 0 5

South Dakota 32 9 2 5 0 1 0 1

Tennessee 114 23 1 7 2 8 1 4

Texas 779 96 23 27 6 15 1 24

Utah 142 16 2 3 1 3 0 7

Vermont 18 5 1 3 0 1 0 0

Virgin Islands 2 1 1 0 0 0 0 0

Virginia 158 27 4 7 0 5 0 11

Washington 253 29 8 4 8 3 2 4

West Virginia 46 12 1 7 0 2 0 2

Wisconsin 149 17 8 0 3 2 1 3

Wyoming 16 4 0 3 0 1 0 0

Tribes - Region 1 0 0 0 0 0 0 0 0

Tribes - Region 5 0 0 0 0 0 0 0 0

Tribes - Region 6 4 2 2 0 0 0 0 0

Tribes - Region 8 0 0 0 0 0 0 0 0

Tribes - Region 9 16 2 0 2 0 0 0 0

Total 11,193 1,198 240 240 151 169 63 335 1

 The UCMR data are not representative at the state-level.

Number of Very Large Systems 

(serving >100,000 people)

State 1

Total 

Number of 

Samples

Total 

Number of 

Systems

Number of Small Systems 

(serving ≤10,000 people)

Number of Large Systems 

(serving 10,001 - 100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 28 of 50

Table B14. Alachlor - UCMR 2 Screening Survey Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 2,040,600 17,259 9,693 103,109 204,295 0 1,706,245

Alaska 143,305 90 8,049 0 0 0 135,166

American Samoa 0 0 0 0 0 0 0

Arizona 3,403,868 14,319 1,729 113,300 0 675,445 2,599,075

Arkansas 845,459 11,365 8,930 85,674 52,858 0 686,632

California 24,372,007 29,816 49,813 1,008,796 1,303,622 1,088,908 20,891,052

Colorado 3,219,993 8,226 15,710 31,000 128,361 0 3,036,696

Connecticut 1,497,295 1,004 6,620 17,500 94,362 0 1,377,809

Delaware 484,765 4,383 0 34,878 0 0 445,504

District of Columbia 783,055 0 0 0 0 0 783,055

Florida 11,889,692 31,802 7,075 1,732,771 31,152 7,266,168 2,820,724

Georgia 4,397,366 9,885 12,463 39,543 211,034 163,688 3,960,753

Guam 100,001 0 0 0 0 100,001 0

Hawaii 854,836 4,958 0 63,155 0 786,723 0

Idaho 280,917 5,329 1,237 88,351 0 0 186,000

Illinois 5,680,520 22,938 20,358 71,451 364,550 405,228 4,795,996

Indiana 2,277,440 14,331 9,489 216,877 70,123 113,400 1,853,220

Iowa 805,109 14,756 7,369 146,216 81,086 0 555,682

Kansas 1,331,673 6,004 14,995 41,348 11,025 0 1,258,301

Kentucky 1,962,150 0 17,056 0 258,661 85,697 1,600,737

Louisiana 2,049,851 22,928 7,429 115,495 69,144 663,655 1,171,200

Maine 132,909 724 7,600 0 11,025 0 113,560

Maryland 3,874,592 6,534 7,390 64,801 13,200 249,600 3,533,067

Massachusetts 5,202,826 10,300 12,914 130,449 249,899 159,180 4,640,084

Michigan 4,826,722 12,746 12,269 97,711 130,537 283,846 4,289,613

Minnesota 1,400,744 10,862 7,501 300,404 148,200 0 933,777

Mississippi 424,022 31,538 0 49,302 0 0 343,182

Missouri 2,793,981 11,698 13,341 97,715 77,092 223,971 2,370,164

Montana 112,643 3,104 6,168 0 0 0 103,371

N. Mariana Islands 0 0 0 0 0 0 0

Navajo Nation 21,873 3,629 0 18,244 0 0 0

Nebraska 743,335 4,946 2,500 21,000 0 0 714,889

Nevada 1,908,764 6,832 237 0 56,000 0 1,845,695

New Hampshire 165,859 950 1,595 0 11,250 0 152,064

New Jersey 4,449,920 10,749 0 91,759 118,127 115,378 4,113,907

New Mexico 568,968 7,769 2,846 105,000 0 453,353 0

New York 12,173,772 8,634 35,158 248,594 225,437 1,682,822 9,973,127

North Carolina 3,220,020 15,311 26,493 111,438 311,061 108,666 2,647,052

North Dakota 92,952 1,099 1,254 0 90,599 0 0

Ohio 5,968,446 21,415 12,060 300,293 263,264 123,850 5,247,564

Oklahoma 1,432,777 6,402 25,003 15,435 128,486 0 1,257,451

Oregon 1,505,465 7,740 18,036 0 123,120 0 1,356,569

Pennsylvania 5,612,428 14,708 33,537 0 390,681 0 5,173,502

Puerto Rico 3,794,459 4,955 17,083 112,793 220,732 0 3,438,896

Rhode Island 613,600 355 0 0 61,709 0 551,536

South Carolina 1,604,882 8,549 10,201 53,122 181,122 0 1,351,888

South Dakota 152,210 811 3,162 0 20,237 0 128,000

Tennessee 2,104,138 8,587 31,013 66,568 371,290 687,096 939,584

Texas 14,372,970 60,963 89,693 228,445 691,230 1,253,442 12,049,197

Utah 1,362,703 8,500 9,345 24,000 160,956 0 1,159,902

Vermont 63,618 298 11,570 0 51,750 0 0

Virgin Islands 50 50 0 0 0 0 0

Virginia 3,377,005 3,451 21,232 0 143,889 0 3,208,433

Washington 2,706,556 15,667 6,360 404,649 93,417 374,556 1,811,906

West Virginia 434,635 424 26,216 0 78,231 0 329,764

Wisconsin 1,507,678 17,221 0 133,000 82,035 205,247 1,070,175

Wyoming 68,027 0 8,043 0 59,984 0 0

Tribes - Region 1 0 0 0 0 0 0 0

Tribes - Region 5 0 0 0 0 0 0 0

Tribes - Region 6 1,450 1,450 0 0 0 0 0

Tribes - Region 8 0 0 0 0 0 0 0

Tribes - Region 9 2,722 0 2,722 0 0 0 0

Total 157,219,620 548,364 660,557 6,584,184 7,444,830 17,269,919 124,711,765 1

 The UCMR data are not representative at the state-level.

State 1

Total 

Population 

Served

Pop. Served by Small Systems 

(serving ≤10,000 people)

Pop. Served by Large Systems 

(serving 10,001 - 100,000 people)

Pop. Served by Very Large Systems 

(serving >100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 29 of 50

Table B15. Alachlor ESA - UCMR 2 Screening Survey Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 147 20 4 2 3 5 0 6

Alaska 58 9 1 7 0 0 0 1

American Samoa 0 0 0 0 0 0 0 0

Arizona 382 19 4 2 3 0 1 9

Arkansas 68 13 3 3 2 2 0 3

California 3,350 154 13 28 19 22 8 64

Colorado 158 26 3 9 1 3 0 10

Connecticut 83 12 3 1 1 2 0 5

Delaware 83 5 1 0 1 0 0 3

District of Columbia 8 1 0 0 0 0 0 1

Florida 432 79 11 1 31 1 23 12

Georgia 169 31 6 5 2 5 1 12

Guam 220 1 0 0 0 0 1 0

Hawaii 140 4 1 0 1 0 2 0

Idaho 67 9 3 3 2 0 0 1

Illinois 270 35 7 5 4 8 3 8

Indiana 109 21 5 2 5 2 1 6

Iowa 82 15 5 2 3 2 0 3

Kansas 76 16 3 5 1 1 0 6

Kentucky 83 17 0 4 0 8 1 4

Louisiana 209 22 8 2 3 2 3 4

Maine 22 6 2 2 0 1 0 1

Maryland 60 13 3 3 2 1 1 3

Massachusetts 135 24 4 2 4 5 1 8

Michigan 145 23 9 2 2 3 2 5

Minnesota 59 18 6 1 7 2 0 2

Mississippi 82 15 10 0 3 0 0 2

Missouri 95 20 6 4 3 2 1 4

Montana 24 7 2 4 0 0 0 1

N. Mariana Islands 0 0 0 0 0 0 0 0

Navajo Nation 14 3 2 0 1 0 0 0

Nebraska 45 7 3 1 1 0 0 2

Nevada 98 8 2 1 0 1 0 4

New Hampshire 17 6 3 1 0 1 0 1

New Jersey 257 26 6 0 4 4 1 11

New Mexico 110 8 3 2 2 0 1 0

New York 848 53 8 14 6 6 5 14

North Carolina 209 35 7 5 3 7 1 12

North Dakota 14 4 1 2 0 1 0 0

Ohio 152 36 7 5 7 6 1 10

Oklahoma 83 19 3 9 1 3 0 3

Oregon 84 17 3 6 0 3 0 5

Pennsylvania 334 51 10 14 0 9 0 18

Puerto Rico 275 27 2 10 2 5 0 8

Rhode Island 18 4 1 0 0 1 0 2

South Carolina 70 16 3 3 1 4 0 5

South Dakota 32 9 2 5 0 1 0 1

Tennessee 114 23 1 7 2 8 1 4

Texas 776 96 23 27 6 15 1 24

Utah 142 16 2 3 1 3 0 7

Vermont 17 5 1 3 0 1 0 0

Virgin Islands 2 1 1 0 0 0 0 0

Virginia 158 27 4 7 0 5 0 11

Washington 241 29 8 4 8 3 2 4

West Virginia 46 12 1 7 0 2 0 2

Wisconsin 149 17 8 0 3 2 1 3

Wyoming 16 4 0 3 0 1 0 0

Tribes - Region 1 0 0 0 0 0 0 0 0

Tribes - Region 5 0 0 0 0 0 0 0 0

Tribes - Region 6 3 2 2 0 0 0 0 0

Tribes - Region 8 0 0 0 0 0 0 0 0

Tribes - Region 9 16 2 0 2 0 0 0 0

Total 11,156 1,198 240 240 151 169 63 335 1

 The UCMR data are not representative at the state-level.

Number of Very Large Systems 

(serving >100,000 people)

State 1

Total 

Number of 

Samples

Total 

Number of 

Systems

Number of Small Systems 

(serving ≤10,000 people)

Number of Large Systems 

(serving 10,001 - 100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 30 of 50

Table B15. Alachlor ESA - UCMR 2 Screening Survey Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 2,040,600 17,259 9,693 103,109 204,295 0 1,706,245

Alaska 143,305 90 8,049 0 0 0 135,166

American Samoa 0 0 0 0 0 0 0

Arizona 3,403,868 14,319 1,729 113,300 0 675,445 2,599,075

Arkansas 845,459 11,365 8,930 85,674 52,858 0 686,632

California 24,372,007 29,816 49,813 1,008,796 1,303,622 1,088,908 20,891,052

Colorado 3,219,993 8,226 15,710 31,000 128,361 0 3,036,696

Connecticut 1,497,295 1,004 6,620 17,500 94,362 0 1,377,809

Delaware 484,765 4,383 0 34,878 0 0 445,504

District of Columbia 783,055 0 0 0 0 0 783,055

Florida 11,889,692 31,802 7,075 1,732,771 31,152 7,266,168 2,820,724

Georgia 4,397,366 9,885 12,463 39,543 211,034 163,688 3,960,753

Guam 100,001 0 0 0 0 100,001 0

Hawaii 854,836 4,958 0 63,155 0 786,723 0

Idaho 280,917 5,329 1,237 88,351 0 0 186,000

Illinois 5,680,520 22,938 20,358 71,451 364,550 405,228 4,795,996

Indiana 2,277,440 14,331 9,489 216,877 70,123 113,400 1,853,220

Iowa 805,109 14,756 7,369 146,216 81,086 0 555,682

Kansas 1,331,673 6,004 14,995 41,348 11,025 0 1,258,301

Kentucky 1,962,150 0 17,056 0 258,661 85,697 1,600,737

Louisiana 2,049,851 22,928 7,429 115,495 69,144 663,655 1,171,200

Maine 132,909 724 7,600 0 11,025 0 113,560

Maryland 3,874,592 6,534 7,390 64,801 13,200 249,600 3,533,067

Massachusetts 5,202,826 10,300 12,914 130,449 249,899 159,180 4,640,084

Michigan 4,826,722 12,746 12,269 97,711 130,537 283,846 4,289,613

Minnesota 1,400,744 10,862 7,501 300,404 148,200 0 933,777

Mississippi 424,022 31,538 0 49,302 0 0 343,182

Missouri 2,793,981 11,698 13,341 97,715 77,092 223,971 2,370,164

Montana 112,643 3,104 6,168 0 0 0 103,371

N. Mariana Islands 0 0 0 0 0 0 0

Navajo Nation 21,873 3,629 0 18,244 0 0 0

Nebraska 743,335 4,946 2,500 21,000 0 0 714,889

Nevada 1,908,764 6,832 237 0 56,000 0 1,845,695

New Hampshire 165,859 950 1,595 0 11,250 0 152,064

New Jersey 4,449,920 10,749 0 91,759 118,127 115,378 4,113,907

New Mexico 568,968 7,769 2,846 105,000 0 453,353 0

New York 12,173,772 8,634 35,158 248,594 225,437 1,682,822 9,973,127

North Carolina 3,220,020 15,311 26,493 111,438 311,061 108,666 2,647,052

North Dakota 92,952 1,099 1,254 0 90,599 0 0

Ohio 5,968,446 21,415 12,060 300,293 263,264 123,850 5,247,564

Oklahoma 1,432,777 6,402 25,003 15,435 128,486 0 1,257,451

Oregon 1,505,465 7,740 18,036 0 123,120 0 1,356,569

Pennsylvania 5,612,428 14,708 33,537 0 390,681 0 5,173,502

Puerto Rico 3,794,459 4,955 17,083 112,793 220,732 0 3,438,896

Rhode Island 613,600 355 0 0 61,709 0 551,536

South Carolina 1,604,882 8,549 10,201 53,122 181,122 0 1,351,888

South Dakota 152,210 811 3,162 0 20,237 0 128,000

Tennessee 2,104,138 8,587 31,013 66,568 371,290 687,096 939,584

Texas 14,372,970 60,963 89,693 228,445 691,230 1,253,442 12,049,197

Utah 1,362,703 8,500 9,345 24,000 160,956 0 1,159,902

Vermont 63,618 298 11,570 0 51,750 0 0

Virgin Islands 50 50 0 0 0 0 0

Virginia 3,377,005 3,451 21,232 0 143,889 0 3,208,433

Washington 2,706,556 15,667 6,360 404,649 93,417 374,556 1,811,906

West Virginia 434,635 424 26,216 0 78,231 0 329,764

Wisconsin 1,507,678 17,221 0 133,000 82,035 205,247 1,070,175

Wyoming 68,027 0 8,043 0 59,984 0 0

Tribes - Region 1 0 0 0 0 0 0 0

Tribes - Region 5 0 0 0 0 0 0 0

Tribes - Region 6 1,450 1,450 0 0 0 0 0

Tribes - Region 8 0 0 0 0 0 0 0

Tribes - Region 9 2,722 0 2,722 0 0 0 0

Total 157,219,620 548,364 660,557 6,584,184 7,444,830 17,269,919 124,711,765 1

 The UCMR data are not representative at the state-level.

State 1

Total 

Population 

Served

Pop. Served by Small Systems 

(serving ≤10,000 people)

Pop. Served by Large Systems 

(serving 10,001 - 100,000 people)

Pop. Served by Very Large Systems 

(serving >100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 31 of 50

Table B16. Alachlor OA - UCMR 2 Screening Survey Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 147 20 4 2 3 5 0 6

Alaska 58 9 1 7 0 0 0 1

American Samoa 0 0 0 0 0 0 0 0

Arizona 382 19 4 2 3 0 1 9

Arkansas 68 13 3 3 2 2 0 3

California 3,351 154 13 28 19 22 8 64

Colorado 158 26 3 9 1 3 0 10

Connecticut 83 12 3 1 1 2 0 5

Delaware 83 5 1 0 1 0 0 3

District of Columbia 8 1 0 0 0 0 0 1

Florida 432 79 11 1 31 1 23 12

Georgia 169 31 6 5 2 5 1 12

Guam 220 1 0 0 0 0 1 0

Hawaii 140 4 1 0 1 0 2 0

Idaho 67 9 3 3 2 0 0 1

Illinois 270 35 7 5 4 8 3 8

Indiana 109 21 5 2 5 2 1 6

Iowa 82 15 5 2 3 2 0 3

Kansas 76 16 3 5 1 1 0 6

Kentucky 83 17 0 4 0 8 1 4

Louisiana 209 22 8 2 3 2 3 4

Maine 22 6 2 2 0 1 0 1

Maryland 60 13 3 3 2 1 1 3

Massachusetts 135 24 4 2 4 5 1 8

Michigan 145 23 9 2 2 3 2 5

Minnesota 59 18 6 1 7 2 0 2

Mississippi 82 15 10 0 3 0 0 2

Missouri 95 20 6 4 3 2 1 4

Montana 24 7 2 4 0 0 0 1

N. Mariana Islands 0 0 0 0 0 0 0 0

Navajo Nation 14 3 2 0 1 0 0 0

Nebraska 45 7 3 1 1 0 0 2

Nevada 98 8 2 1 0 1 0 4

New Hampshire 17 6 3 1 0 1 0 1

New Jersey 257 26 6 0 4 4 1 11

New Mexico 110 8 3 2 2 0 1 0

New York 848 53 8 14 6 6 5 14

North Carolina 209 35 7 5 3 7 1 12

North Dakota 14 4 1 2 0 1 0 0

Ohio 152 36 7 5 7 6 1 10

Oklahoma 83 19 3 9 1 3 0 3

Oregon 84 17 3 6 0 3 0 5

Pennsylvania 334 51 10 14 0 9 0 18

Puerto Rico 275 27 2 10 2 5 0 8

Rhode Island 18 4 1 0 0 1 0 2

South Carolina 70 16 3 3 1 4 0 5

South Dakota 32 9 2 5 0 1 0 1

Tennessee 114 23 1 7 2 8 1 4

Texas 776 96 23 27 6 15 1 24

Utah 142 16 2 3 1 3 0 7

Vermont 17 5 1 3 0 1 0 0

Virgin Islands 2 1 1 0 0 0 0 0

Virginia 158 27 4 7 0 5 0 11

Washington 241 29 8 4 8 3 2 4

West Virginia 46 12 1 7 0 2 0 2

Wisconsin 149 17 8 0 3 2 1 3

Wyoming 16 4 0 3 0 1 0 0

Tribes - Region 1 0 0 0 0 0 0 0 0

Tribes - Region 5 0 0 0 0 0 0 0 0

Tribes - Region 6 3 2 2 0 0 0 0 0

Tribes - Region 8 0 0 0 0 0 0 0 0

Tribes - Region 9 16 2 0 2 0 0 0 0

Total 11,157 1,198 240 240 151 169 63 335 1

 The UCMR data are not representative at the state-level.

Number of Very Large Systems 

(serving >100,000 people)

State 1

Total 

Number of 

Samples

Total 

Number of 

Systems

Number of Small Systems 

(serving ≤10,000 people)

Number of Large Systems 

(serving 10,001 - 100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 32 of 50

Table B16. Alachlor OA - UCMR 2 Screening Survey Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 2,040,600 17,259 9,693 103,109 204,295 0 1,706,245

Alaska 143,305 90 8,049 0 0 0 135,166

American Samoa 0 0 0 0 0 0 0

Arizona 3,403,868 14,319 1,729 113,300 0 675,445 2,599,075

Arkansas 845,459 11,365 8,930 85,674 52,858 0 686,632

California 24,372,007 29,816 49,813 1,008,796 1,303,622 1,088,908 20,891,052

Colorado 3,219,993 8,226 15,710 31,000 128,361 0 3,036,696

Connecticut 1,497,295 1,004 6,620 17,500 94,362 0 1,377,809

Delaware 484,765 4,383 0 34,878 0 0 445,504

District of Columbia 783,055 0 0 0 0 0 783,055

Florida 11,889,692 31,802 7,075 1,732,771 31,152 7,266,168 2,820,724

Georgia 4,397,366 9,885 12,463 39,543 211,034 163,688 3,960,753

Guam 100,001 0 0 0 0 100,001 0

Hawaii 854,836 4,958 0 63,155 0 786,723 0

Idaho 280,917 5,329 1,237 88,351 0 0 186,000

Illinois 5,680,520 22,938 20,358 71,451 364,550 405,228 4,795,996

Indiana 2,277,440 14,331 9,489 216,877 70,123 113,400 1,853,220

Iowa 805,109 14,756 7,369 146,216 81,086 0 555,682

Kansas 1,331,673 6,004 14,995 41,348 11,025 0 1,258,301

Kentucky 1,962,150 0 17,056 0 258,661 85,697 1,600,737

Louisiana 2,049,851 22,928 7,429 115,495 69,144 663,655 1,171,200

Maine 132,909 724 7,600 0 11,025 0 113,560

Maryland 3,874,592 6,534 7,390 64,801 13,200 249,600 3,533,067

Massachusetts 5,202,826 10,300 12,914 130,449 249,899 159,180 4,640,084

Michigan 4,826,722 12,746 12,269 97,711 130,537 283,846 4,289,613

Minnesota 1,400,744 10,862 7,501 300,404 148,200 0 933,777

Mississippi 424,022 31,538 0 49,302 0 0 343,182

Missouri 2,793,981 11,698 13,341 97,715 77,092 223,971 2,370,164

Montana 112,643 3,104 6,168 0 0 0 103,371

N. Mariana Islands 0 0 0 0 0 0 0

Navajo Nation 21,873 3,629 0 18,244 0 0 0

Nebraska 743,335 4,946 2,500 21,000 0 0 714,889

Nevada 1,908,764 6,832 237 0 56,000 0 1,845,695

New Hampshire 165,859 950 1,595 0 11,250 0 152,064

New Jersey 4,449,920 10,749 0 91,759 118,127 115,378 4,113,907

New Mexico 568,968 7,769 2,846 105,000 0 453,353 0

New York 12,173,772 8,634 35,158 248,594 225,437 1,682,822 9,973,127

North Carolina 3,220,020 15,311 26,493 111,438 311,061 108,666 2,647,052

North Dakota 92,952 1,099 1,254 0 90,599 0 0

Ohio 5,968,446 21,415 12,060 300,293 263,264 123,850 5,247,564

Oklahoma 1,432,777 6,402 25,003 15,435 128,486 0 1,257,451

Oregon 1,505,465 7,740 18,036 0 123,120 0 1,356,569

Pennsylvania 5,612,428 14,708 33,537 0 390,681 0 5,173,502

Puerto Rico 3,794,459 4,955 17,083 112,793 220,732 0 3,438,896

Rhode Island 613,600 355 0 0 61,709 0 551,536

South Carolina 1,604,882 8,549 10,201 53,122 181,122 0 1,351,888

South Dakota 152,210 811 3,162 0 20,237 0 128,000

Tennessee 2,104,138 8,587 31,013 66,568 371,290 687,096 939,584

Texas 14,372,970 60,963 89,693 228,445 691,230 1,253,442 12,049,197

Utah 1,362,703 8,500 9,345 24,000 160,956 0 1,159,902

Vermont 63,618 298 11,570 0 51,750 0 0

Virgin Islands 50 50 0 0 0 0 0

Virginia 3,377,005 3,451 21,232 0 143,889 0 3,208,433

Washington 2,706,556 15,667 6,360 404,649 93,417 374,556 1,811,906

West Virginia 434,635 424 26,216 0 78,231 0 329,764

Wisconsin 1,507,678 17,221 0 133,000 82,035 205,247 1,070,175

Wyoming 68,027 0 8,043 0 59,984 0 0

Tribes - Region 1 0 0 0 0 0 0 0

Tribes - Region 5 0 0 0 0 0 0 0

Tribes - Region 6 1,450 1,450 0 0 0 0 0

Tribes - Region 8 0 0 0 0 0 0 0

Tribes - Region 9 2,722 0 2,722 0 0 0 0

Total 157,219,620 548,364 660,557 6,584,184 7,444,830 17,269,919 124,711,765 1

 The UCMR data are not representative at the state-level.

State 1

Total 

Population 

Served

Pop. Served by Small Systems 

(serving ≤10,000 people)

Pop. Served by Large Systems 

(serving 10,001 - 100,000 people)

Pop. Served by Very Large Systems 

(serving >100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 33 of 50

Table B17. Metolachlor - UCMR 2 Screening Survey Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 147 20 4 2 3 5 0 6

Alaska 58 9 1 7 0 0 0 1

American Samoa 0 0 0 0 0 0 0 0

Arizona 382 19 4 2 3 0 1 9

Arkansas 68 13 3 3 2 2 0 3

California 3,347 154 13 28 19 22 8 64

Colorado 159 26 3 9 1 3 0 10

Connecticut 83 12 3 1 1 2 0 5

Delaware 83 5 1 0 1 0 0 3

District of Columbia 8 1 0 0 0 0 0 1

Florida 433 79 11 1 31 1 23 12

Georgia 170 31 6 5 2 5 1 12

Guam 219 1 0 0 0 0 1 0

Hawaii 140 4 1 0 1 0 2 0

Idaho 67 9 3 3 2 0 0 1

Illinois 270 35 7 5 4 8 3 8

Indiana 109 21 5 2 5 2 1 6

Iowa 82 15 5 2 3 2 0 3

Kansas 76 16 3 5 1 1 0 6

Kentucky 83 17 0 4 0 8 1 4

Louisiana 212 22 8 2 3 2 3 4

Maine 22 6 2 2 0 1 0 1

Maryland 60 13 3 3 2 1 1 3

Massachusetts 141 24 4 2 4 5 1 8

Michigan 146 23 9 2 2 3 2 5

Minnesota 59 18 6 1 7 2 0 2

Mississippi 82 15 10 0 3 0 0 2

Missouri 96 20 6 4 3 2 1 4

Montana 24 7 2 4 0 0 0 1

N. Mariana Islands 0 0 0 0 0 0 0 0

Navajo Nation 14 3 2 0 1 0 0 0

Nebraska 45 7 3 1 1 0 0 2

Nevada 98 8 2 1 0 1 0 4

New Hampshire 17 6 3 1 0 1 0 1

New Jersey 257 26 6 0 4 4 1 11

New Mexico 110 8 3 2 2 0 1 0

New York 857 53 8 14 6 6 5 14

North Carolina 210 35 7 5 3 7 1 12

North Dakota 14 4 1 2 0 1 0 0

Ohio 152 36 7 5 7 6 1 10

Oklahoma 83 19 3 9 1 3 0 3

Oregon 84 17 3 6 0 3 0 5

Pennsylvania 333 51 10 14 0 9 0 18

Puerto Rico 275 27 2 10 2 5 0 8

Rhode Island 18 4 1 0 0 1 0 2

South Carolina 70 16 3 3 1 4 0 5

South Dakota 32 9 2 5 0 1 0 1

Tennessee 114 23 1 7 2 8 1 4

Texas 779 96 23 27 6 15 1 24

Utah 142 16 2 3 1 3 0 7

Vermont 18 5 1 3 0 1 0 0

Virgin Islands 2 1 1 0 0 0 0 0

Virginia 158 27 4 7 0 5 0 11

Washington 253 29 8 4 8 3 2 4

West Virginia 46 12 1 7 0 2 0 2

Wisconsin 149 17 8 0 3 2 1 3

Wyoming 16 4 0 3 0 1 0 0

Tribes - Region 1 0 0 0 0 0 0 0 0

Tribes - Region 5 0 0 0 0 0 0 0 0

Tribes - Region 6 4 2 2 0 0 0 0 0

Tribes - Region 8 0 0 0 0 0 0 0 0

Tribes - Region 9 16 2 0 2 0 0 0 0

Total 11,192 1,198 240 240 151 169 63 335 1

 The UCMR data are not representative at the state-level.

Number of Very Large Systems 

(serving >100,000 people)

State 1

Total 

Number of 

Samples

Total 

Number of 

Systems

Number of Small Systems 

(serving ≤10,000 people)

Number of Large Systems 

(serving 10,001 - 100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 34 of 50

Table B17. Metolachlor - UCMR 2 Screening Survey Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 2,040,600 17,259 9,693 103,109 204,295 0 1,706,245

Alaska 143,305 90 8,049 0 0 0 135,166

American Samoa 0 0 0 0 0 0 0

Arizona 3,403,868 14,319 1,729 113,300 0 675,445 2,599,075

Arkansas 845,459 11,365 8,930 85,674 52,858 0 686,632

California 24,372,007 29,816 49,813 1,008,796 1,303,622 1,088,908 20,891,052

Colorado 3,219,993 8,226 15,710 31,000 128,361 0 3,036,696

Connecticut 1,497,295 1,004 6,620 17,500 94,362 0 1,377,809

Delaware 484,765 4,383 0 34,878 0 0 445,504

District of Columbia 783,055 0 0 0 0 0 783,055

Florida 11,889,692 31,802 7,075 1,732,771 31,152 7,266,168 2,820,724

Georgia 4,397,366 9,885 12,463 39,543 211,034 163,688 3,960,753

Guam 100,001 0 0 0 0 100,001 0

Hawaii 854,836 4,958 0 63,155 0 786,723 0

Idaho 280,917 5,329 1,237 88,351 0 0 186,000

Illinois 5,680,520 22,938 20,358 71,451 364,550 405,228 4,795,996

Indiana 2,277,440 14,331 9,489 216,877 70,123 113,400 1,853,220

Iowa 805,109 14,756 7,369 146,216 81,086 0 555,682

Kansas 1,331,673 6,004 14,995 41,348 11,025 0 1,258,301

Kentucky 1,962,150 0 17,056 0 258,661 85,697 1,600,737

Louisiana 2,049,851 22,928 7,429 115,495 69,144 663,655 1,171,200

Maine 132,909 724 7,600 0 11,025 0 113,560

Maryland 3,874,592 6,534 7,390 64,801 13,200 249,600 3,533,067

Massachusetts 5,202,826 10,300 12,914 130,449 249,899 159,180 4,640,084

Michigan 4,826,722 12,746 12,269 97,711 130,537 283,846 4,289,613

Minnesota 1,400,744 10,862 7,501 300,404 148,200 0 933,777

Mississippi 424,022 31,538 0 49,302 0 0 343,182

Missouri 2,793,981 11,698 13,341 97,715 77,092 223,971 2,370,164

Montana 112,643 3,104 6,168 0 0 0 103,371

N. Mariana Islands 0 0 0 0 0 0 0

Navajo Nation 21,873 3,629 0 18,244 0 0 0

Nebraska 743,335 4,946 2,500 21,000 0 0 714,889

Nevada 1,908,764 6,832 237 0 56,000 0 1,845,695

New Hampshire 165,859 950 1,595 0 11,250 0 152,064

New Jersey 4,449,920 10,749 0 91,759 118,127 115,378 4,113,907

New Mexico 568,968 7,769 2,846 105,000 0 453,353 0

New York 12,173,772 8,634 35,158 248,594 225,437 1,682,822 9,973,127

North Carolina 3,220,020 15,311 26,493 111,438 311,061 108,666 2,647,052

North Dakota 92,952 1,099 1,254 0 90,599 0 0

Ohio 5,968,446 21,415 12,060 300,293 263,264 123,850 5,247,564

Oklahoma 1,432,777 6,402 25,003 15,435 128,486 0 1,257,451

Oregon 1,505,465 7,740 18,036 0 123,120 0 1,356,569

Pennsylvania 5,612,428 14,708 33,537 0 390,681 0 5,173,502

Puerto Rico 3,794,459 4,955 17,083 112,793 220,732 0 3,438,896

Rhode Island 613,600 355 0 0 61,709 0 551,536

South Carolina 1,604,882 8,549 10,201 53,122 181,122 0 1,351,888

South Dakota 152,210 811 3,162 0 20,237 0 128,000

Tennessee 2,104,138 8,587 31,013 66,568 371,290 687,096 939,584

Texas 14,372,970 60,963 89,693 228,445 691,230 1,253,442 12,049,197

Utah 1,362,703 8,500 9,345 24,000 160,956 0 1,159,902

Vermont 63,618 298 11,570 0 51,750 0 0

Virgin Islands 50 50 0 0 0 0 0

Virginia 3,377,005 3,451 21,232 0 143,889 0 3,208,433

Washington 2,706,556 15,667 6,360 404,649 93,417 374,556 1,811,906

West Virginia 434,635 424 26,216 0 78,231 0 329,764

Wisconsin 1,507,678 17,221 0 133,000 82,035 205,247 1,070,175

Wyoming 68,027 0 8,043 0 59,984 0 0

Tribes - Region 1 0 0 0 0 0 0 0

Tribes - Region 5 0 0 0 0 0 0 0

Tribes - Region 6 1,450 1,450 0 0 0 0 0

Tribes - Region 8 0 0 0 0 0 0 0

Tribes - Region 9 2,722 0 2,722 0 0 0 0

Total 157,219,620 548,364 660,557 6,584,184 7,444,830 17,269,919 124,711,765 1

 The UCMR data are not representative at the state-level.

State 1

Total 

Population 

Served

Pop. Served by Small Systems 

(serving ≤10,000 people)

Pop. Served by Large Systems 

(serving 10,001 - 100,000 people)

Pop. Served by Very Large Systems 

(serving >100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 35 of 50

Table B18. Metolachlor ESA - UCMR 2 Screening Survey Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 147 20 4 2 3 5 0 6

Alaska 58 9 1 7 0 0 0 1

American Samoa 0 0 0 0 0 0 0 0

Arizona 382 19 4 2 3 0 1 9

Arkansas 68 13 3 3 2 2 0 3

California 3,351 154 13 28 19 22 8 64

Colorado 158 26 3 9 1 3 0 10

Connecticut 83 12 3 1 1 2 0 5

Delaware 83 5 1 0 1 0 0 3

District of Columbia 8 1 0 0 0 0 0 1

Florida 432 79 11 1 31 1 23 12

Georgia 169 31 6 5 2 5 1 12

Guam 220 1 0 0 0 0 1 0

Hawaii 140 4 1 0 1 0 2 0

Idaho 67 9 3 3 2 0 0 1

Illinois 270 35 7 5 4 8 3 8

Indiana 109 21 5 2 5 2 1 6

Iowa 82 15 5 2 3 2 0 3

Kansas 76 16 3 5 1 1 0 6

Kentucky 83 17 0 4 0 8 1 4

Louisiana 209 22 8 2 3 2 3 4

Maine 22 6 2 2 0 1 0 1

Maryland 60 13 3 3 2 1 1 3

Massachusetts 135 24 4 2 4 5 1 8

Michigan 145 23 9 2 2 3 2 5

Minnesota 59 18 6 1 7 2 0 2

Mississippi 82 15 10 0 3 0 0 2

Missouri 95 20 6 4 3 2 1 4

Montana 24 7 2 4 0 0 0 1

N. Mariana Islands 0 0 0 0 0 0 0 0

Navajo Nation 14 3 2 0 1 0 0 0

Nebraska 45 7 3 1 1 0 0 2

Nevada 98 8 2 1 0 1 0 4

New Hampshire 17 6 3 1 0 1 0 1

New Jersey 257 26 6 0 4 4 1 11

New Mexico 110 8 3 2 2 0 1 0

New York 848 53 8 14 6 6 5 14

North Carolina 209 35 7 5 3 7 1 12

North Dakota 14 4 1 2 0 1 0 0

Ohio 152 36 7 5 7 6 1 10

Oklahoma 83 19 3 9 1 3 0 3

Oregon 84 17 3 6 0 3 0 5

Pennsylvania 334 51 10 14 0 9 0 18

Puerto Rico 275 27 2 10 2 5 0 8

Rhode Island 18 4 1 0 0 1 0 2

South Carolina 70 16 3 3 1 4 0 5

South Dakota 32 9 2 5 0 1 0 1

Tennessee 114 23 1 7 2 8 1 4

Texas 776 96 23 27 6 15 1 24

Utah 142 16 2 3 1 3 0 7

Vermont 17 5 1 3 0 1 0 0

Virgin Islands 2 1 1 0 0 0 0 0

Virginia 158 27 4 7 0 5 0 11

Washington 241 29 8 4 8 3 2 4

West Virginia 46 12 1 7 0 2 0 2

Wisconsin 149 17 8 0 3 2 1 3

Wyoming 16 4 0 3 0 1 0 0

Tribes - Region 1 0 0 0 0 0 0 0 0

Tribes - Region 5 0 0 0 0 0 0 0 0

Tribes - Region 6 3 2 2 0 0 0 0 0

Tribes - Region 8 0 0 0 0 0 0 0 0

Tribes - Region 9 16 2 0 2 0 0 0 0

Total 11,157 1,198 240 240 151 169 63 335 1

 The UCMR data are not representative at the state-level.

Number of Very Large Systems 

(serving >100,000 people)

State 1

Total 

Number of 

Samples

Total 

Number of 

Systems

Number of Small Systems 

(serving ≤10,000 people)

Number of Large Systems 

(serving 10,001 - 100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 36 of 50

Table B18. Metolachlor ESA - UCMR 2 Screening Survey Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 2,040,600 17,259 9,693 103,109 204,295 0 1,706,245

Alaska 143,305 90 8,049 0 0 0 135,166

American Samoa 0 0 0 0 0 0 0

Arizona 3,403,868 14,319 1,729 113,300 0 675,445 2,599,075

Arkansas 845,459 11,365 8,930 85,674 52,858 0 686,632

California 24,372,007 29,816 49,813 1,008,796 1,303,622 1,088,908 20,891,052

Colorado 3,219,993 8,226 15,710 31,000 128,361 0 3,036,696

Connecticut 1,497,295 1,004 6,620 17,500 94,362 0 1,377,809

Delaware 484,765 4,383 0 34,878 0 0 445,504

District of Columbia 783,055 0 0 0 0 0 783,055

Florida 11,889,692 31,802 7,075 1,732,771 31,152 7,266,168 2,820,724

Georgia 4,397,366 9,885 12,463 39,543 211,034 163,688 3,960,753

Guam 100,001 0 0 0 0 100,001 0

Hawaii 854,836 4,958 0 63,155 0 786,723 0

Idaho 280,917 5,329 1,237 88,351 0 0 186,000

Illinois 5,680,520 22,938 20,358 71,451 364,550 405,228 4,795,996

Indiana 2,277,440 14,331 9,489 216,877 70,123 113,400 1,853,220

Iowa 805,109 14,756 7,369 146,216 81,086 0 555,682

Kansas 1,331,673 6,004 14,995 41,348 11,025 0 1,258,301

Kentucky 1,962,150 0 17,056 0 258,661 85,697 1,600,737

Louisiana 2,049,851 22,928 7,429 115,495 69,144 663,655 1,171,200

Maine 132,909 724 7,600 0 11,025 0 113,560

Maryland 3,874,592 6,534 7,390 64,801 13,200 249,600 3,533,067

Massachusetts 5,202,826 10,300 12,914 130,449 249,899 159,180 4,640,084

Michigan 4,826,722 12,746 12,269 97,711 130,537 283,846 4,289,613

Minnesota 1,400,744 10,862 7,501 300,404 148,200 0 933,777

Mississippi 424,022 31,538 0 49,302 0 0 343,182

Missouri 2,793,981 11,698 13,341 97,715 77,092 223,971 2,370,164

Montana 112,643 3,104 6,168 0 0 0 103,371

N. Mariana Islands 0 0 0 0 0 0 0

Navajo Nation 21,873 3,629 0 18,244 0 0 0

Nebraska 743,335 4,946 2,500 21,000 0 0 714,889

Nevada 1,908,764 6,832 237 0 56,000 0 1,845,695

New Hampshire 165,859 950 1,595 0 11,250 0 152,064

New Jersey 4,449,920 10,749 0 91,759 118,127 115,378 4,113,907

New Mexico 568,968 7,769 2,846 105,000 0 453,353 0

New York 12,173,772 8,634 35,158 248,594 225,437 1,682,822 9,973,127

North Carolina 3,220,020 15,311 26,493 111,438 311,061 108,666 2,647,052

North Dakota 92,952 1,099 1,254 0 90,599 0 0

Ohio 5,968,446 21,415 12,060 300,293 263,264 123,850 5,247,564

Oklahoma 1,432,777 6,402 25,003 15,435 128,486 0 1,257,451

Oregon 1,505,465 7,740 18,036 0 123,120 0 1,356,569

Pennsylvania 5,612,428 14,708 33,537 0 390,681 0 5,173,502

Puerto Rico 3,794,459 4,955 17,083 112,793 220,732 0 3,438,896

Rhode Island 613,600 355 0 0 61,709 0 551,536

South Carolina 1,604,882 8,549 10,201 53,122 181,122 0 1,351,888

South Dakota 152,210 811 3,162 0 20,237 0 128,000

Tennessee 2,104,138 8,587 31,013 66,568 371,290 687,096 939,584

Texas 14,372,970 60,963 89,693 228,445 691,230 1,253,442 12,049,197

Utah 1,362,703 8,500 9,345 24,000 160,956 0 1,159,902

Vermont 63,618 298 11,570 0 51,750 0 0

Virgin Islands 50 50 0 0 0 0 0

Virginia 3,377,005 3,451 21,232 0 143,889 0 3,208,433

Washington 2,706,556 15,667 6,360 404,649 93,417 374,556 1,811,906

West Virginia 434,635 424 26,216 0 78,231 0 329,764

Wisconsin 1,507,678 17,221 0 133,000 82,035 205,247 1,070,175

Wyoming 68,027 0 8,043 0 59,984 0 0

Tribes - Region 1 0 0 0 0 0 0 0

Tribes - Region 5 0 0 0 0 0 0 0

Tribes - Region 6 1,450 1,450 0 0 0 0 0

Tribes - Region 8 0 0 0 0 0 0 0

Tribes - Region 9 2,722 0 2,722 0 0 0 0

Total 157,219,620 548,364 660,557 6,584,184 7,444,830 17,269,919 124,711,765 1

 The UCMR data are not representative at the state-level.

State 1

Total 

Population 

Served

Pop. Served by Small Systems 

(serving ≤10,000 people)

Pop. Served by Large Systems 

(serving 10,001 - 100,000 people)

Pop. Served by Very Large Systems 

(serving >100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 37 of 50

Table B19. Metolachlor OA - UCMR 2 Screening Survey Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 147 20 4 2 3 5 0 6

Alaska 58 9 1 7 0 0 0 1

American Samoa 0 0 0 0 0 0 0 0

Arizona 382 19 4 2 3 0 1 9

Arkansas 68 13 3 3 2 2 0 3

California 3,351 154 13 28 19 22 8 64

Colorado 158 26 3 9 1 3 0 10

Connecticut 83 12 3 1 1 2 0 5

Delaware 83 5 1 0 1 0 0 3

District of Columbia 8 1 0 0 0 0 0 1

Florida 432 79 11 1 31 1 23 12

Georgia 169 31 6 5 2 5 1 12

Guam 220 1 0 0 0 0 1 0

Hawaii 140 4 1 0 1 0 2 0

Idaho 67 9 3 3 2 0 0 1

Illinois 270 35 7 5 4 8 3 8

Indiana 109 21 5 2 5 2 1 6

Iowa 82 15 5 2 3 2 0 3

Kansas 76 16 3 5 1 1 0 6

Kentucky 83 17 0 4 0 8 1 4

Louisiana 209 22 8 2 3 2 3 4

Maine 22 6 2 2 0 1 0 1

Maryland 60 13 3 3 2 1 1 3

Massachusetts 135 24 4 2 4 5 1 8

Michigan 145 23 9 2 2 3 2 5

Minnesota 59 18 6 1 7 2 0 2

Mississippi 82 15 10 0 3 0 0 2

Missouri 95 20 6 4 3 2 1 4

Montana 24 7 2 4 0 0 0 1

N. Mariana Islands 0 0 0 0 0 0 0 0

Navajo Nation 14 3 2 0 1 0 0 0

Nebraska 45 7 3 1 1 0 0 2

Nevada 98 8 2 1 0 1 0 4

New Hampshire 17 6 3 1 0 1 0 1

New Jersey 257 26 6 0 4 4 1 11

New Mexico 110 8 3 2 2 0 1 0

New York 848 53 8 14 6 6 5 14

North Carolina 209 35 7 5 3 7 1 12

North Dakota 14 4 1 2 0 1 0 0

Ohio 152 36 7 5 7 6 1 10

Oklahoma 83 19 3 9 1 3 0 3

Oregon 84 17 3 6 0 3 0 5

Pennsylvania 334 51 10 14 0 9 0 18

Puerto Rico 275 27 2 10 2 5 0 8

Rhode Island 18 4 1 0 0 1 0 2

South Carolina 70 16 3 3 1 4 0 5

South Dakota 32 9 2 5 0 1 0 1

Tennessee 114 23 1 7 2 8 1 4

Texas 776 96 23 27 6 15 1 24

Utah 142 16 2 3 1 3 0 7

Vermont 17 5 1 3 0 1 0 0

Virgin Islands 2 1 1 0 0 0 0 0

Virginia 158 27 4 7 0 5 0 11

Washington 241 29 8 4 8 3 2 4

West Virginia 46 12 1 7 0 2 0 2

Wisconsin 149 17 8 0 3 2 1 3

Wyoming 16 4 0 3 0 1 0 0

Tribes - Region 1 0 0 0 0 0 0 0 0

Tribes - Region 5 0 0 0 0 0 0 0 0

Tribes - Region 6 3 2 2 0 0 0 0 0

Tribes - Region 8 0 0 0 0 0 0 0 0

Tribes - Region 9 16 2 0 2 0 0 0 0

Total 11,157 1,198 240 240 151 169 63 335 1

 The UCMR data are not representative at the state-level.

Number of Very Large Systems 

(serving >100,000 people)

State 1

Total 

Number of 

Samples

Total 

Number of 

Systems

Number of Small Systems 

(serving ≤10,000 people)

Number of Large Systems 

(serving 10,001 - 100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 38 of 50

Table B19. Metolachlor OA - UCMR 2 Screening Survey Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 2,040,600 17,259 9,693 103,109 204,295 0 1,706,245

Alaska 143,305 90 8,049 0 0 0 135,166

American Samoa 0 0 0 0 0 0 0

Arizona 3,403,868 14,319 1,729 113,300 0 675,445 2,599,075

Arkansas 845,459 11,365 8,930 85,674 52,858 0 686,632

California 24,372,007 29,816 49,813 1,008,796 1,303,622 1,088,908 20,891,052

Colorado 3,219,993 8,226 15,710 31,000 128,361 0 3,036,696

Connecticut 1,497,295 1,004 6,620 17,500 94,362 0 1,377,809

Delaware 484,765 4,383 0 34,878 0 0 445,504

District of Columbia 783,055 0 0 0 0 0 783,055

Florida 11,889,692 31,802 7,075 1,732,771 31,152 7,266,168 2,820,724

Georgia 4,397,366 9,885 12,463 39,543 211,034 163,688 3,960,753

Guam 100,001 0 0 0 0 100,001 0

Hawaii 854,836 4,958 0 63,155 0 786,723 0

Idaho 280,917 5,329 1,237 88,351 0 0 186,000

Illinois 5,680,520 22,938 20,358 71,451 364,550 405,228 4,795,996

Indiana 2,277,440 14,331 9,489 216,877 70,123 113,400 1,853,220

Iowa 805,109 14,756 7,369 146,216 81,086 0 555,682

Kansas 1,331,673 6,004 14,995 41,348 11,025 0 1,258,301

Kentucky 1,962,150 0 17,056 0 258,661 85,697 1,600,737

Louisiana 2,049,851 22,928 7,429 115,495 69,144 663,655 1,171,200

Maine 132,909 724 7,600 0 11,025 0 113,560

Maryland 3,874,592 6,534 7,390 64,801 13,200 249,600 3,533,067

Massachusetts 5,202,826 10,300 12,914 130,449 249,899 159,180 4,640,084

Michigan 4,826,722 12,746 12,269 97,711 130,537 283,846 4,289,613

Minnesota 1,400,744 10,862 7,501 300,404 148,200 0 933,777

Mississippi 424,022 31,538 0 49,302 0 0 343,182

Missouri 2,793,981 11,698 13,341 97,715 77,092 223,971 2,370,164

Montana 112,643 3,104 6,168 0 0 0 103,371

N. Mariana Islands 0 0 0 0 0 0 0

Navajo Nation 21,873 3,629 0 18,244 0 0 0

Nebraska 743,335 4,946 2,500 21,000 0 0 714,889

Nevada 1,908,764 6,832 237 0 56,000 0 1,845,695

New Hampshire 165,859 950 1,595 0 11,250 0 152,064

New Jersey 4,449,920 10,749 0 91,759 118,127 115,378 4,113,907

New Mexico 568,968 7,769 2,846 105,000 0 453,353 0

New York 12,173,772 8,634 35,158 248,594 225,437 1,682,822 9,973,127

North Carolina 3,220,020 15,311 26,493 111,438 311,061 108,666 2,647,052

North Dakota 92,952 1,099 1,254 0 90,599 0 0

Ohio 5,968,446 21,415 12,060 300,293 263,264 123,850 5,247,564

Oklahoma 1,432,777 6,402 25,003 15,435 128,486 0 1,257,451

Oregon 1,505,465 7,740 18,036 0 123,120 0 1,356,569

Pennsylvania 5,612,428 14,708 33,537 0 390,681 0 5,173,502

Puerto Rico 3,794,459 4,955 17,083 112,793 220,732 0 3,438,896

Rhode Island 613,600 355 0 0 61,709 0 551,536

South Carolina 1,604,882 8,549 10,201 53,122 181,122 0 1,351,888

South Dakota 152,210 811 3,162 0 20,237 0 128,000

Tennessee 2,104,138 8,587 31,013 66,568 371,290 687,096 939,584

Texas 14,372,970 60,963 89,693 228,445 691,230 1,253,442 12,049,197

Utah 1,362,703 8,500 9,345 24,000 160,956 0 1,159,902

Vermont 63,618 298 11,570 0 51,750 0 0

Virgin Islands 50 50 0 0 0 0 0

Virginia 3,377,005 3,451 21,232 0 143,889 0 3,208,433

Washington 2,706,556 15,667 6,360 404,649 93,417 374,556 1,811,906

West Virginia 434,635 424 26,216 0 78,231 0 329,764

Wisconsin 1,507,678 17,221 0 133,000 82,035 205,247 1,070,175

Wyoming 68,027 0 8,043 0 59,984 0 0

Tribes - Region 1 0 0 0 0 0 0 0

Tribes - Region 5 0 0 0 0 0 0 0

Tribes - Region 6 1,450 1,450 0 0 0 0 0

Tribes - Region 8 0 0 0 0 0 0 0

Tribes - Region 9 2,722 0 2,722 0 0 0 0

Total 157,219,620 548,364 660,557 6,584,184 7,444,830 17,269,919 124,711,765 1

 The UCMR data are not representative at the state-level.

State 1

Total 

Population 

Served

Pop. Served by Small Systems 

(serving ≤10,000 people)

Pop. Served by Large Systems 

(serving 10,001 - 100,000 people)

Pop. Served by Very Large Systems 

(serving >100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 39 of 50

Table B20. NDBA - UCMR 2 Screening Survey Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 270 20 4 2 3 5 0 6

Alaska 97 9 1 7 0 0 0 1

American Samoa 0 0 0 0 0 0 0 0

Arizona 753 19 4 2 3 0 1 9

Arkansas 116 13 3 3 2 2 0 3

California 4,394 154 13 28 19 22 8 64

Colorado 319 26 3 9 1 3 0 10

Connecticut 165 12 3 1 1 2 0 5

Delaware 117 5 1 0 1 0 0 3

District of Columbia 8 1 0 0 0 0 0 1

Florida 793 79 11 1 31 1 23 12

Georgia 315 31 6 5 2 5 1 12

Guam 233 1 0 0 0 0 1 0

Hawaii 161 4 1 0 1 0 2 0

Idaho 109 9 3 3 2 0 0 1

Illinois 392 35 7 5 4 8 3 8

Indiana 203 21 5 2 5 2 1 6

Iowa 130 15 5 2 3 2 0 3

Kansas 140 16 3 5 1 1 0 6

Kentucky 156 17 0 4 0 8 1 4

Louisiana 302 22 8 2 3 2 3 4

Maine 39 6 2 2 0 1 0 1

Maryland 120 13 3 3 2 1 1 3

Massachusetts 221 24 4 2 4 5 1 8

Michigan 255 23 9 2 2 3 2 5

Minnesota 103 18 6 1 7 2 0 2

Mississippi 114 15 10 0 3 0 0 2

Missouri 167 20 6 4 3 2 1 4

Montana 48 7 2 4 0 0 0 1

N. Mariana Islands 0 0 0 0 0 0 0 0

Navajo Nation 30 3 2 0 1 0 0 0

Nebraska 71 7 3 1 1 0 0 2

Nevada 147 8 2 1 0 1 0 4

New Hampshire 31 6 3 1 0 1 0 1

New Jersey 375 26 6 0 4 4 1 11

New Mexico 132 8 3 2 2 0 1 0

New York 1,540 53 8 14 6 6 5 14

North Carolina 355 35 7 5 3 7 1 12

North Dakota 28 4 1 2 0 1 0 0

Ohio 297 36 7 5 7 6 1 10

Oklahoma 158 19 3 9 1 3 0 3

Oregon 147 17 3 6 0 3 0 5

Pennsylvania 656 51 10 14 0 9 0 18

Puerto Rico 569 27 2 10 2 5 0 8

Rhode Island 30 4 1 0 0 1 0 2

South Carolina 140 16 3 3 1 4 0 5

South Dakota 62 9 2 5 0 1 0 1

Tennessee 226 23 1 7 2 8 1 4

Texas 1,627 96 23 27 6 15 1 24

Utah 200 16 2 3 1 3 0 7

Vermont 36 5 1 3 0 1 0 0

Virgin Islands 4 1 1 0 0 0 0 0

Virginia 285 27 4 7 0 5 0 11

Washington 350 29 8 4 8 3 2 4

West Virginia 86 12 1 7 0 2 0 2

Wisconsin 214 17 8 0 3 2 1 3

Wyoming 33 4 0 3 0 1 0 0

Tribes - Region 1 0 0 0 0 0 0 0 0

Tribes - Region 5 0 0 0 0 0 0 0 0

Tribes - Region 6 8 2 2 0 0 0 0 0

Tribes - Region 8 0 0 0 0 0 0 0 0

Tribes - Region 9 24 2 0 2 0 0 0 0

Total 18,101 1,198 240 240 151 169 63 335 1

 The UCMR data are not representative at the state-level.

Number of Very Large Systems 

(serving >100,000 people)

State 1

Total 

Number of 

Samples

Total 

Number of 

Systems

Number of Small Systems 

(serving ≤10,000 people)

Number of Large Systems 

(serving 10,001 - 100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 40 of 50

Table B20. NDBA - UCMR 2 Screening Survey Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 2,040,600 17,259 9,693 103,109 204,295 0 1,706,245

Alaska 143,305 90 8,049 0 0 0 135,166

American Samoa 0 0 0 0 0 0 0

Arizona 3,403,868 14,319 1,729 113,300 0 675,445 2,599,075

Arkansas 845,459 11,365 8,930 85,674 52,858 0 686,632

California 24,372,007 29,816 49,813 1,008,796 1,303,622 1,088,908 20,891,052

Colorado 3,219,993 8,226 15,710 31,000 128,361 0 3,036,696

Connecticut 1,497,295 1,004 6,620 17,500 94,362 0 1,377,809

Delaware 484,765 4,383 0 34,878 0 0 445,504

District of Columbia 783,055 0 0 0 0 0 783,055

Florida 11,889,692 31,802 7,075 1,732,771 31,152 7,266,168 2,820,724

Georgia 4,397,366 9,885 12,463 39,543 211,034 163,688 3,960,753

Guam 100,001 0 0 0 0 100,001 0

Hawaii 854,836 4,958 0 63,155 0 786,723 0

Idaho 280,917 5,329 1,237 88,351 0 0 186,000

Illinois 5,680,520 22,938 20,358 71,451 364,550 405,228 4,795,996

Indiana 2,277,440 14,331 9,489 216,877 70,123 113,400 1,853,220

Iowa 805,109 14,756 7,369 146,216 81,086 0 555,682

Kansas 1,331,673 6,004 14,995 41,348 11,025 0 1,258,301

Kentucky 1,962,150 0 17,056 0 258,661 85,697 1,600,737

Louisiana 2,049,851 22,928 7,429 115,495 69,144 663,655 1,171,200

Maine 132,909 724 7,600 0 11,025 0 113,560

Maryland 3,874,592 6,534 7,390 64,801 13,200 249,600 3,533,067

Massachusetts 5,202,826 10,300 12,914 130,449 249,899 159,180 4,640,084

Michigan 4,826,722 12,746 12,269 97,711 130,537 283,846 4,289,613

Minnesota 1,400,744 10,862 7,501 300,404 148,200 0 933,777

Mississippi 424,022 31,538 0 49,302 0 0 343,182

Missouri 2,793,981 11,698 13,341 97,715 77,092 223,971 2,370,164

Montana 112,643 3,104 6,168 0 0 0 103,371

N. Mariana Islands 0 0 0 0 0 0 0

Navajo Nation 21,873 3,629 0 18,244 0 0 0

Nebraska 743,335 4,946 2,500 21,000 0 0 714,889

Nevada 1,908,764 6,832 237 0 56,000 0 1,845,695

New Hampshire 165,859 950 1,595 0 11,250 0 152,064

New Jersey 4,449,920 10,749 0 91,759 118,127 115,378 4,113,907

New Mexico 568,968 7,769 2,846 105,000 0 453,353 0

New York 12,173,772 8,634 35,158 248,594 225,437 1,682,822 9,973,127

North Carolina 3,220,020 15,311 26,493 111,438 311,061 108,666 2,647,052

North Dakota 92,952 1,099 1,254 0 90,599 0 0

Ohio 5,968,446 21,415 12,060 300,293 263,264 123,850 5,247,564

Oklahoma 1,432,777 6,402 25,003 15,435 128,486 0 1,257,451

Oregon 1,505,465 7,740 18,036 0 123,120 0 1,356,569

Pennsylvania 5,612,428 14,708 33,537 0 390,681 0 5,173,502

Puerto Rico 3,794,459 4,955 17,083 112,793 220,732 0 3,438,896

Rhode Island 613,600 355 0 0 61,709 0 551,536

South Carolina 1,604,882 8,549 10,201 53,122 181,122 0 1,351,888

South Dakota 152,210 811 3,162 0 20,237 0 128,000

Tennessee 2,104,138 8,587 31,013 66,568 371,290 687,096 939,584

Texas 14,372,970 60,963 89,693 228,445 691,230 1,253,442 12,049,197

Utah 1,362,703 8,500 9,345 24,000 160,956 0 1,159,902

Vermont 63,618 298 11,570 0 51,750 0 0

Virgin Islands 50 50 0 0 0 0 0

Virginia 3,377,005 3,451 21,232 0 143,889 0 3,208,433

Washington 2,706,556 15,667 6,360 404,649 93,417 374,556 1,811,906

West Virginia 434,635 424 26,216 0 78,231 0 329,764

Wisconsin 1,507,678 17,221 0 133,000 82,035 205,247 1,070,175

Wyoming 68,027 0 8,043 0 59,984 0 0

Tribes - Region 1 0 0 0 0 0 0 0

Tribes - Region 5 0 0 0 0 0 0 0

Tribes - Region 6 1,450 1,450 0 0 0 0 0

Tribes - Region 8 0 0 0 0 0 0 0

Tribes - Region 9 2,722 0 2,722 0 0 0 0

Total 157,219,620 548,364 660,557 6,584,184 7,444,830 17,269,919 124,711,765 1

 The UCMR data are not representative at the state-level.

State 1

Total 

Population 

Served

Pop. Served by Small Systems 

(serving ≤10,000 people)

Pop. Served by Large Systems 

(serving 10,001 - 100,000 people)

Pop. Served by Very Large Systems 

(serving >100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 41 of 50

Table B21. NDEA - UCMR 2 Screening Survey Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 270 20 4 2 3 5 0 6

Alaska 97 9 1 7 0 0 0 1

American Samoa 0 0 0 0 0 0 0 0

Arizona 753 19 4 2 3 0 1 9

Arkansas 116 13 3 3 2 2 0 3

California 4,382 154 13 28 19 22 8 64

Colorado 319 26 3 9 1 3 0 10

Connecticut 165 12 3 1 1 2 0 5

Delaware 117 5 1 0 1 0 0 3

District of Columbia 8 1 0 0 0 0 0 1

Florida 793 79 11 1 31 1 23 12

Georgia 315 31 6 5 2 5 1 12

Guam 233 1 0 0 0 0 1 0

Hawaii 161 4 1 0 1 0 2 0

Idaho 109 9 3 3 2 0 0 1

Illinois 392 35 7 5 4 8 3 8

Indiana 203 21 5 2 5 2 1 6

Iowa 130 15 5 2 3 2 0 3

Kansas 140 16 3 5 1 1 0 6

Kentucky 156 17 0 4 0 8 1 4

Louisiana 302 22 8 2 3 2 3 4

Maine 39 6 2 2 0 1 0 1

Maryland 120 13 3 3 2 1 1 3

Massachusetts 221 24 4 2 4 5 1 8

Michigan 255 23 9 2 2 3 2 5

Minnesota 103 18 6 1 7 2 0 2

Mississippi 114 15 10 0 3 0 0 2

Missouri 167 20 6 4 3 2 1 4

Montana 48 7 2 4 0 0 0 1

N. Mariana Islands 0 0 0 0 0 0 0 0

Navajo Nation 30 3 2 0 1 0 0 0

Nebraska 71 7 3 1 1 0 0 2

Nevada 147 8 2 1 0 1 0 4

New Hampshire 31 6 3 1 0 1 0 1

New Jersey 375 26 6 0 4 4 1 11

New Mexico 132 8 3 2 2 0 1 0

New York 1,540 53 8 14 6 6 5 14

North Carolina 355 35 7 5 3 7 1 12

North Dakota 28 4 1 2 0 1 0 0

Ohio 297 36 7 5 7 6 1 10

Oklahoma 158 19 3 9 1 3 0 3

Oregon 147 17 3 6 0 3 0 5

Pennsylvania 656 51 10 14 0 9 0 18

Puerto Rico 569 27 2 10 2 5 0 8

Rhode Island 30 4 1 0 0 1 0 2

South Carolina 140 16 3 3 1 4 0 5

South Dakota 62 9 2 5 0 1 0 1

Tennessee 226 23 1 7 2 8 1 4

Texas 1,634 96 23 27 6 15 1 24

Utah 200 16 2 3 1 3 0 7

Vermont 36 5 1 3 0 1 0 0

Virgin Islands 4 1 1 0 0 0 0 0

Virginia 285 27 4 7 0 5 0 11

Washington 350 29 8 4 8 3 2 4

West Virginia 86 12 1 7 0 2 0 2

Wisconsin 214 17 8 0 3 2 1 3

Wyoming 33 4 0 3 0 1 0 0

Tribes - Region 1 0 0 0 0 0 0 0 0

Tribes - Region 5 0 0 0 0 0 0 0 0

Tribes - Region 6 8 2 2 0 0 0 0 0

Tribes - Region 8 0 0 0 0 0 0 0 0

Tribes - Region 9 24 2 0 2 0 0 0 0

Total 18,096 1,198 240 240 151 169 63 335 1

 The UCMR data are not representative at the state-level.

Number of Very Large Systems 

(serving >100,000 people)

State 1

Total 

Number of 

Samples

Total 

Number of 

Systems

Number of Small Systems 

(serving ≤10,000 people)

Number of Large Systems 

(serving 10,001 - 100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 42 of 50

Table B21. NDEA - UCMR 2 Screening Survey Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 2,040,600 17,259 9,693 103,109 204,295 0 1,706,245

Alaska 143,305 90 8,049 0 0 0 135,166

American Samoa 0 0 0 0 0 0 0

Arizona 3,403,868 14,319 1,729 113,300 0 675,445 2,599,075

Arkansas 845,459 11,365 8,930 85,674 52,858 0 686,632

California 24,372,007 29,816 49,813 1,008,796 1,303,622 1,088,908 20,891,052

Colorado 3,219,993 8,226 15,710 31,000 128,361 0 3,036,696

Connecticut 1,497,295 1,004 6,620 17,500 94,362 0 1,377,809

Delaware 484,765 4,383 0 34,878 0 0 445,504

District of Columbia 783,055 0 0 0 0 0 783,055

Florida 11,889,692 31,802 7,075 1,732,771 31,152 7,266,168 2,820,724

Georgia 4,397,366 9,885 12,463 39,543 211,034 163,688 3,960,753

Guam 100,001 0 0 0 0 100,001 0

Hawaii 854,836 4,958 0 63,155 0 786,723 0

Idaho 280,917 5,329 1,237 88,351 0 0 186,000

Illinois 5,680,520 22,938 20,358 71,451 364,550 405,228 4,795,996

Indiana 2,277,440 14,331 9,489 216,877 70,123 113,400 1,853,220

Iowa 805,109 14,756 7,369 146,216 81,086 0 555,682

Kansas 1,331,673 6,004 14,995 41,348 11,025 0 1,258,301

Kentucky 1,962,150 0 17,056 0 258,661 85,697 1,600,737

Louisiana 2,049,851 22,928 7,429 115,495 69,144 663,655 1,171,200

Maine 132,909 724 7,600 0 11,025 0 113,560

Maryland 3,874,592 6,534 7,390 64,801 13,200 249,600 3,533,067

Massachusetts 5,202,826 10,300 12,914 130,449 249,899 159,180 4,640,084

Michigan 4,826,722 12,746 12,269 97,711 130,537 283,846 4,289,613

Minnesota 1,400,744 10,862 7,501 300,404 148,200 0 933,777

Mississippi 424,022 31,538 0 49,302 0 0 343,182

Missouri 2,793,981 11,698 13,341 97,715 77,092 223,971 2,370,164

Montana 112,643 3,104 6,168 0 0 0 103,371

N. Mariana Islands 0 0 0 0 0 0 0

Navajo Nation 21,873 3,629 0 18,244 0 0 0

Nebraska 743,335 4,946 2,500 21,000 0 0 714,889

Nevada 1,908,764 6,832 237 0 56,000 0 1,845,695

New Hampshire 165,859 950 1,595 0 11,250 0 152,064

New Jersey 4,449,920 10,749 0 91,759 118,127 115,378 4,113,907

New Mexico 568,968 7,769 2,846 105,000 0 453,353 0

New York 12,173,772 8,634 35,158 248,594 225,437 1,682,822 9,973,127

North Carolina 3,220,020 15,311 26,493 111,438 311,061 108,666 2,647,052

North Dakota 92,952 1,099 1,254 0 90,599 0 0

Ohio 5,968,446 21,415 12,060 300,293 263,264 123,850 5,247,564

Oklahoma 1,432,777 6,402 25,003 15,435 128,486 0 1,257,451

Oregon 1,505,465 7,740 18,036 0 123,120 0 1,356,569

Pennsylvania 5,612,428 14,708 33,537 0 390,681 0 5,173,502

Puerto Rico 3,794,459 4,955 17,083 112,793 220,732 0 3,438,896

Rhode Island 613,600 355 0 0 61,709 0 551,536

South Carolina 1,604,882 8,549 10,201 53,122 181,122 0 1,351,888

South Dakota 152,210 811 3,162 0 20,237 0 128,000

Tennessee 2,104,138 8,587 31,013 66,568 371,290 687,096 939,584

Texas 14,372,970 60,963 89,693 228,445 691,230 1,253,442 12,049,197

Utah 1,362,703 8,500 9,345 24,000 160,956 0 1,159,902

Vermont 63,618 298 11,570 0 51,750 0 0

Virgin Islands 50 50 0 0 0 0 0

Virginia 3,377,005 3,451 21,232 0 143,889 0 3,208,433

Washington 2,706,556 15,667 6,360 404,649 93,417 374,556 1,811,906

West Virginia 434,635 424 26,216 0 78,231 0 329,764

Wisconsin 1,507,678 17,221 0 133,000 82,035 205,247 1,070,175

Wyoming 68,027 0 8,043 0 59,984 0 0

Tribes - Region 1 0 0 0 0 0 0 0

Tribes - Region 5 0 0 0 0 0 0 0

Tribes - Region 6 1,450 1,450 0 0 0 0 0

Tribes - Region 8 0 0 0 0 0 0 0

Tribes - Region 9 2,722 0 2,722 0 0 0 0

Total 157,219,620 548,364 660,557 6,584,184 7,444,830 17,269,919 124,711,765 1

 The UCMR data are not representative at the state-level.

State 1

Total 

Population 

Served

Pop. Served by Small Systems 

(serving ≤10,000 people)

Pop. Served by Large Systems 

(serving 10,001 - 100,000 people)

Pop. Served by Very Large Systems 

(serving >100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 43 of 50

Table B22. NDMA - UCMR 2 Screening Survey Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 270 20 4 2 3 5 0 6

Alaska 97 9 1 7 0 0 0 1

American Samoa 0 0 0 0 0 0 0 0

Arizona 753 19 4 2 3 0 1 9

Arkansas 116 13 3 3 2 2 0 3

California 4,392 154 13 28 19 22 8 64

Colorado 319 26 3 9 1 3 0 10

Connecticut 165 12 3 1 1 2 0 5

Delaware 117 5 1 0 1 0 0 3

District of Columbia 8 1 0 0 0 0 0 1

Florida 793 79 11 1 31 1 23 12

Georgia 315 31 6 5 2 5 1 12

Guam 233 1 0 0 0 0 1 0

Hawaii 161 4 1 0 1 0 2 0

Idaho 109 9 3 3 2 0 0 1

Illinois 392 35 7 5 4 8 3 8

Indiana 203 21 5 2 5 2 1 6

Iowa 130 15 5 2 3 2 0 3

Kansas 140 16 3 5 1 1 0 6

Kentucky 156 17 0 4 0 8 1 4

Louisiana 302 22 8 2 3 2 3 4

Maine 39 6 2 2 0 1 0 1

Maryland 120 13 3 3 2 1 1 3

Massachusetts 220 24 4 2 4 5 1 8

Michigan 255 23 9 2 2 3 2 5

Minnesota 103 18 6 1 7 2 0 2

Mississippi 114 15 10 0 3 0 0 2

Missouri 167 20 6 4 3 2 1 4

Montana 48 7 2 4 0 0 0 1

N. Mariana Islands 0 0 0 0 0 0 0 0

Navajo Nation 30 3 2 0 1 0 0 0

Nebraska 71 7 3 1 1 0 0 2

Nevada 147 8 2 1 0 1 0 4

New Hampshire 31 6 3 1 0 1 0 1

New Jersey 375 26 6 0 4 4 1 11

New Mexico 132 8 3 2 2 0 1 0

New York 1,540 53 8 14 6 6 5 14

North Carolina 355 35 7 5 3 7 1 12

North Dakota 28 4 1 2 0 1 0 0

Ohio 297 36 7 5 7 6 1 10

Oklahoma 158 19 3 9 1 3 0 3

Oregon 147 17 3 6 0 3 0 5

Pennsylvania 656 51 10 14 0 9 0 18

Puerto Rico 569 27 2 10 2 5 0 8

Rhode Island 30 4 1 0 0 1 0 2

South Carolina 140 16 3 3 1 4 0 5

South Dakota 62 9 2 5 0 1 0 1

Tennessee 226 23 1 7 2 8 1 4

Texas 1,627 96 23 27 6 15 1 24

Utah 200 16 2 3 1 3 0 7

Vermont 36 5 1 3 0 1 0 0

Virgin Islands 4 1 1 0 0 0 0 0

Virginia 285 27 4 7 0 5 0 11

Washington 350 29 8 4 8 3 2 4

West Virginia 86 12 1 7 0 2 0 2

Wisconsin 214 17 8 0 3 2 1 3

Wyoming 33 4 0 3 0 1 0 0

Tribes - Region 1 0 0 0 0 0 0 0 0

Tribes - Region 5 0 0 0 0 0 0 0 0

Tribes - Region 6 8 2 2 0 0 0 0 0

Tribes - Region 8 0 0 0 0 0 0 0 0

Tribes - Region 9 24 2 0 2 0 0 0 0

Total 18,098 1,198 240 240 151 169 63 335 1

 The UCMR data are not representative at the state-level.

Number of Very Large Systems 

(serving >100,000 people)

State 1

Total 

Number of 

Samples

Total 

Number of 

Systems

Number of Small Systems 

(serving ≤10,000 people)

Number of Large Systems 

(serving 10,001 - 100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 44 of 50

Table B22. NDMA - UCMR 2 Screening Survey Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 2,040,600 17,259 9,693 103,109 204,295 0 1,706,245

Alaska 143,305 90 8,049 0 0 0 135,166

American Samoa 0 0 0 0 0 0 0

Arizona 3,403,868 14,319 1,729 113,300 0 675,445 2,599,075

Arkansas 845,459 11,365 8,930 85,674 52,858 0 686,632

California 24,372,007 29,816 49,813 1,008,796 1,303,622 1,088,908 20,891,052

Colorado 3,219,993 8,226 15,710 31,000 128,361 0 3,036,696

Connecticut 1,497,295 1,004 6,620 17,500 94,362 0 1,377,809

Delaware 484,765 4,383 0 34,878 0 0 445,504

District of Columbia 783,055 0 0 0 0 0 783,055

Florida 11,889,692 31,802 7,075 1,732,771 31,152 7,266,168 2,820,724

Georgia 4,397,366 9,885 12,463 39,543 211,034 163,688 3,960,753

Guam 100,001 0 0 0 0 100,001 0

Hawaii 854,836 4,958 0 63,155 0 786,723 0

Idaho 280,917 5,329 1,237 88,351 0 0 186,000

Illinois 5,680,520 22,938 20,358 71,451 364,550 405,228 4,795,996

Indiana 2,277,440 14,331 9,489 216,877 70,123 113,400 1,853,220

Iowa 805,109 14,756 7,369 146,216 81,086 0 555,682

Kansas 1,331,673 6,004 14,995 41,348 11,025 0 1,258,301

Kentucky 1,962,150 0 17,056 0 258,661 85,697 1,600,737

Louisiana 2,049,851 22,928 7,429 115,495 69,144 663,655 1,171,200

Maine 132,909 724 7,600 0 11,025 0 113,560

Maryland 3,874,592 6,534 7,390 64,801 13,200 249,600 3,533,067

Massachusetts 5,202,826 10,300 12,914 130,449 249,899 159,180 4,640,084

Michigan 4,826,722 12,746 12,269 97,711 130,537 283,846 4,289,613

Minnesota 1,400,744 10,862 7,501 300,404 148,200 0 933,777

Mississippi 424,022 31,538 0 49,302 0 0 343,182

Missouri 2,793,981 11,698 13,341 97,715 77,092 223,971 2,370,164

Montana 112,643 3,104 6,168 0 0 0 103,371

N. Mariana Islands 0 0 0 0 0 0 0

Navajo Nation 21,873 3,629 0 18,244 0 0 0

Nebraska 743,335 4,946 2,500 21,000 0 0 714,889

Nevada 1,908,764 6,832 237 0 56,000 0 1,845,695

New Hampshire 165,859 950 1,595 0 11,250 0 152,064

New Jersey 4,449,920 10,749 0 91,759 118,127 115,378 4,113,907

New Mexico 568,968 7,769 2,846 105,000 0 453,353 0

New York 12,173,772 8,634 35,158 248,594 225,437 1,682,822 9,973,127

North Carolina 3,220,020 15,311 26,493 111,438 311,061 108,666 2,647,052

North Dakota 92,952 1,099 1,254 0 90,599 0 0

Ohio 5,968,446 21,415 12,060 300,293 263,264 123,850 5,247,564

Oklahoma 1,432,777 6,402 25,003 15,435 128,486 0 1,257,451

Oregon 1,505,465 7,740 18,036 0 123,120 0 1,356,569

Pennsylvania 5,612,428 14,708 33,537 0 390,681 0 5,173,502

Puerto Rico 3,794,459 4,955 17,083 112,793 220,732 0 3,438,896

Rhode Island 613,600 355 0 0 61,709 0 551,536

South Carolina 1,604,882 8,549 10,201 53,122 181,122 0 1,351,888

South Dakota 152,210 811 3,162 0 20,237 0 128,000

Tennessee 2,104,138 8,587 31,013 66,568 371,290 687,096 939,584

Texas 14,372,970 60,963 89,693 228,445 691,230 1,253,442 12,049,197

Utah 1,362,703 8,500 9,345 24,000 160,956 0 1,159,902

Vermont 63,618 298 11,570 0 51,750 0 0

Virgin Islands 50 50 0 0 0 0 0

Virginia 3,377,005 3,451 21,232 0 143,889 0 3,208,433

Washington 2,706,556 15,667 6,360 404,649 93,417 374,556 1,811,906

West Virginia 434,635 424 26,216 0 78,231 0 329,764

Wisconsin 1,507,678 17,221 0 133,000 82,035 205,247 1,070,175

Wyoming 68,027 0 8,043 0 59,984 0 0

Tribes - Region 1 0 0 0 0 0 0 0

Tribes - Region 5 0 0 0 0 0 0 0

Tribes - Region 6 1,450 1,450 0 0 0 0 0

Tribes - Region 8 0 0 0 0 0 0 0

Tribes - Region 9 2,722 0 2,722 0 0 0 0

Total 157,219,620 548,364 660,557 6,584,184 7,444,830 17,269,919 124,711,765 1

 The UCMR data are not representative at the state-level.

State 1

Total 

Population 

Served

Pop. Served by Small Systems 

(serving ≤10,000 people)

Pop. Served by Large Systems 

(serving 10,001 - 100,000 people)

Pop. Served by Very Large Systems 

(serving >100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 45 of 50

Table B23. NDPA - UCMR 2 Screening Survey Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 270 20 4 2 3 5 0 6

Alaska 97 9 1 7 0 0 0 1

American Samoa 0 0 0 0 0 0 0 0

Arizona 753 19 4 2 3 0 1 9

Arkansas 116 13 3 3 2 2 0 3

California 4,394 154 13 28 19 22 8 64

Colorado 319 26 3 9 1 3 0 10

Connecticut 165 12 3 1 1 2 0 5

Delaware 117 5 1 0 1 0 0 3

District of Columbia 8 1 0 0 0 0 0 1

Florida 793 79 11 1 31 1 23 12

Georgia 315 31 6 5 2 5 1 12

Guam 233 1 0 0 0 0 1 0

Hawaii 161 4 1 0 1 0 2 0

Idaho 109 9 3 3 2 0 0 1

Illinois 392 35 7 5 4 8 3 8

Indiana 203 21 5 2 5 2 1 6

Iowa 130 15 5 2 3 2 0 3

Kansas 140 16 3 5 1 1 0 6

Kentucky 156 17 0 4 0 8 1 4

Louisiana 302 22 8 2 3 2 3 4

Maine 39 6 2 2 0 1 0 1

Maryland 120 13 3 3 2 1 1 3

Massachusetts 221 24 4 2 4 5 1 8

Michigan 255 23 9 2 2 3 2 5

Minnesota 103 18 6 1 7 2 0 2

Mississippi 114 15 10 0 3 0 0 2

Missouri 167 20 6 4 3 2 1 4

Montana 48 7 2 4 0 0 0 1

N. Mariana Islands 0 0 0 0 0 0 0 0

Navajo Nation 30 3 2 0 1 0 0 0

Nebraska 71 7 3 1 1 0 0 2

Nevada 147 8 2 1 0 1 0 4

New Hampshire 31 6 3 1 0 1 0 1

New Jersey 375 26 6 0 4 4 1 11

New Mexico 132 8 3 2 2 0 1 0

New York 1,540 53 8 14 6 6 5 14

North Carolina 355 35 7 5 3 7 1 12

North Dakota 28 4 1 2 0 1 0 0

Ohio 297 36 7 5 7 6 1 10

Oklahoma 158 19 3 9 1 3 0 3

Oregon 147 17 3 6 0 3 0 5

Pennsylvania 656 51 10 14 0 9 0 18

Puerto Rico 569 27 2 10 2 5 0 8

Rhode Island 30 4 1 0 0 1 0 2

South Carolina 140 16 3 3 1 4 0 5

South Dakota 62 9 2 5 0 1 0 1

Tennessee 226 23 1 7 2 8 1 4

Texas 1,633 96 23 27 6 15 1 24

Utah 200 16 2 3 1 3 0 7

Vermont 36 5 1 3 0 1 0 0

Virgin Islands 4 1 1 0 0 0 0 0

Virginia 285 27 4 7 0 5 0 11

Washington 350 29 8 4 8 3 2 4

West Virginia 86 12 1 7 0 2 0 2

Wisconsin 214 17 8 0 3 2 1 3

Wyoming 33 4 0 3 0 1 0 0

Tribes - Region 1 0 0 0 0 0 0 0 0

Tribes - Region 5 0 0 0 0 0 0 0 0

Tribes - Region 6 8 2 2 0 0 0 0 0

Tribes - Region 8 0 0 0 0 0 0 0 0

Tribes - Region 9 24 2 0 2 0 0 0 0

Total 18,107 1,198 240 240 151 169 63 335 1

 The UCMR data are not representative at the state-level.

Number of Very Large Systems 

(serving >100,000 people)

State 1

Total 

Number of 

Samples

Total 

Number of 

Systems

Number of Small Systems 

(serving ≤10,000 people)

Number of Large Systems 

(serving 10,001 - 100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 46 of 50

Table B23. NDPA - UCMR 2 Screening Survey Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 2,040,600 17,259 9,693 103,109 204,295 0 1,706,245

Alaska 143,305 90 8,049 0 0 0 135,166

American Samoa 0 0 0 0 0 0 0

Arizona 3,403,868 14,319 1,729 113,300 0 675,445 2,599,075

Arkansas 845,459 11,365 8,930 85,674 52,858 0 686,632

California 24,372,007 29,816 49,813 1,008,796 1,303,622 1,088,908 20,891,052

Colorado 3,219,993 8,226 15,710 31,000 128,361 0 3,036,696

Connecticut 1,497,295 1,004 6,620 17,500 94,362 0 1,377,809

Delaware 484,765 4,383 0 34,878 0 0 445,504

District of Columbia 783,055 0 0 0 0 0 783,055

Florida 11,889,692 31,802 7,075 1,732,771 31,152 7,266,168 2,820,724

Georgia 4,397,366 9,885 12,463 39,543 211,034 163,688 3,960,753

Guam 100,001 0 0 0 0 100,001 0

Hawaii 854,836 4,958 0 63,155 0 786,723 0

Idaho 280,917 5,329 1,237 88,351 0 0 186,000

Illinois 5,680,520 22,938 20,358 71,451 364,550 405,228 4,795,996

Indiana 2,277,440 14,331 9,489 216,877 70,123 113,400 1,853,220

Iowa 805,109 14,756 7,369 146,216 81,086 0 555,682

Kansas 1,331,673 6,004 14,995 41,348 11,025 0 1,258,301

Kentucky 1,962,150 0 17,056 0 258,661 85,697 1,600,737

Louisiana 2,049,851 22,928 7,429 115,495 69,144 663,655 1,171,200

Maine 132,909 724 7,600 0 11,025 0 113,560

Maryland 3,874,592 6,534 7,390 64,801 13,200 249,600 3,533,067

Massachusetts 5,202,826 10,300 12,914 130,449 249,899 159,180 4,640,084

Michigan 4,826,722 12,746 12,269 97,711 130,537 283,846 4,289,613

Minnesota 1,400,744 10,862 7,501 300,404 148,200 0 933,777

Mississippi 424,022 31,538 0 49,302 0 0 343,182

Missouri 2,793,981 11,698 13,341 97,715 77,092 223,971 2,370,164

Montana 112,643 3,104 6,168 0 0 0 103,371

N. Mariana Islands 0 0 0 0 0 0 0

Navajo Nation 21,873 3,629 0 18,244 0 0 0

Nebraska 743,335 4,946 2,500 21,000 0 0 714,889

Nevada 1,908,764 6,832 237 0 56,000 0 1,845,695

New Hampshire 165,859 950 1,595 0 11,250 0 152,064

New Jersey 4,449,920 10,749 0 91,759 118,127 115,378 4,113,907

New Mexico 568,968 7,769 2,846 105,000 0 453,353 0

New York 12,173,772 8,634 35,158 248,594 225,437 1,682,822 9,973,127

North Carolina 3,220,020 15,311 26,493 111,438 311,061 108,666 2,647,052

North Dakota 92,952 1,099 1,254 0 90,599 0 0

Ohio 5,968,446 21,415 12,060 300,293 263,264 123,850 5,247,564

Oklahoma 1,432,777 6,402 25,003 15,435 128,486 0 1,257,451

Oregon 1,505,465 7,740 18,036 0 123,120 0 1,356,569

Pennsylvania 5,612,428 14,708 33,537 0 390,681 0 5,173,502

Puerto Rico 3,794,459 4,955 17,083 112,793 220,732 0 3,438,896

Rhode Island 613,600 355 0 0 61,709 0 551,536

South Carolina 1,604,882 8,549 10,201 53,122 181,122 0 1,351,888

South Dakota 152,210 811 3,162 0 20,237 0 128,000

Tennessee 2,104,138 8,587 31,013 66,568 371,290 687,096 939,584

Texas 14,372,970 60,963 89,693 228,445 691,230 1,253,442 12,049,197

Utah 1,362,703 8,500 9,345 24,000 160,956 0 1,159,902

Vermont 63,618 298 11,570 0 51,750 0 0

Virgin Islands 50 50 0 0 0 0 0

Virginia 3,377,005 3,451 21,232 0 143,889 0 3,208,433

Washington 2,706,556 15,667 6,360 404,649 93,417 374,556 1,811,906

West Virginia 434,635 424 26,216 0 78,231 0 329,764

Wisconsin 1,507,678 17,221 0 133,000 82,035 205,247 1,070,175

Wyoming 68,027 0 8,043 0 59,984 0 0

Tribes - Region 1 0 0 0 0 0 0 0

Tribes - Region 5 0 0 0 0 0 0 0

Tribes - Region 6 1,450 1,450 0 0 0 0 0

Tribes - Region 8 0 0 0 0 0 0 0

Tribes - Region 9 2,722 0 2,722 0 0 0 0

Total 157,219,620 548,364 660,557 6,584,184 7,444,830 17,269,919 124,711,765 1

 The UCMR data are not representative at the state-level.

State 1

Total 

Population 

Served

Pop. Served by Small Systems 

(serving ≤10,000 people)

Pop. Served by Large Systems 

(serving 10,001 - 100,000 people)

Pop. Served by Very Large Systems 

(serving >100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 47 of 50

Table B24. NMEA - UCMR 2 Screening Survey Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 270 20 4 2 3 5 0 6

Alaska 97 9 1 7 0 0 0 1

American Samoa 0 0 0 0 0 0 0 0

Arizona 753 19 4 2 3 0 1 9

Arkansas 116 13 3 3 2 2 0 3

California 4,394 154 13 28 19 22 8 64

Colorado 319 26 3 9 1 3 0 10

Connecticut 165 12 3 1 1 2 0 5

Delaware 117 5 1 0 1 0 0 3

District of Columbia 8 1 0 0 0 0 0 1

Florida 793 79 11 1 31 1 23 12

Georgia 315 31 6 5 2 5 1 12

Guam 233 1 0 0 0 0 1 0

Hawaii 161 4 1 0 1 0 2 0

Idaho 109 9 3 3 2 0 0 1

Illinois 392 35 7 5 4 8 3 8

Indiana 203 21 5 2 5 2 1 6

Iowa 130 15 5 2 3 2 0 3

Kansas 140 16 3 5 1 1 0 6

Kentucky 156 17 0 4 0 8 1 4

Louisiana 302 22 8 2 3 2 3 4

Maine 39 6 2 2 0 1 0 1

Maryland 120 13 3 3 2 1 1 3

Massachusetts 221 24 4 2 4 5 1 8

Michigan 255 23 9 2 2 3 2 5

Minnesota 103 18 6 1 7 2 0 2

Mississippi 114 15 10 0 3 0 0 2

Missouri 167 20 6 4 3 2 1 4

Montana 48 7 2 4 0 0 0 1

N. Mariana Islands 0 0 0 0 0 0 0 0

Navajo Nation 30 3 2 0 1 0 0 0

Nebraska 71 7 3 1 1 0 0 2

Nevada 147 8 2 1 0 1 0 4

New Hampshire 31 6 3 1 0 1 0 1

New Jersey 375 26 6 0 4 4 1 11

New Mexico 132 8 3 2 2 0 1 0

New York 1,540 53 8 14 6 6 5 14

North Carolina 355 35 7 5 3 7 1 12

North Dakota 28 4 1 2 0 1 0 0

Ohio 297 36 7 5 7 6 1 10

Oklahoma 158 19 3 9 1 3 0 3

Oregon 147 17 3 6 0 3 0 5

Pennsylvania 656 51 10 14 0 9 0 18

Puerto Rico 569 27 2 10 2 5 0 8

Rhode Island 30 4 1 0 0 1 0 2

South Carolina 140 16 3 3 1 4 0 5

South Dakota 62 9 2 5 0 1 0 1

Tennessee 226 23 1 7 2 8 1 4

Texas 1,627 96 23 27 6 15 1 24

Utah 200 16 2 3 1 3 0 7

Vermont 36 5 1 3 0 1 0 0

Virgin Islands 4 1 1 0 0 0 0 0

Virginia 285 27 4 7 0 5 0 11

Washington 350 29 8 4 8 3 2 4

West Virginia 86 12 1 7 0 2 0 2

Wisconsin 214 17 8 0 3 2 1 3

Wyoming 33 4 0 3 0 1 0 0

Tribes - Region 1 0 0 0 0 0 0 0 0

Tribes - Region 5 0 0 0 0 0 0 0 0

Tribes - Region 6 8 2 2 0 0 0 0 0

Tribes - Region 8 0 0 0 0 0 0 0 0

Tribes - Region 9 24 2 0 2 0 0 0 0

Total 18,101 1,198 240 240 151 169 63 335 1

 The UCMR data are not representative at the state-level.

Number of Very Large Systems 

(serving >100,000 people)

State 1

Total 

Number of 

Samples

Total 

Number of 

Systems

Number of Small Systems 

(serving ≤10,000 people)

Number of Large Systems 

(serving 10,001 - 100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 48 of 50

Table B24. NMEA - UCMR 2 Screening Survey Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 2,040,600 17,259 9,693 103,109 204,295 0 1,706,245

Alaska 143,305 90 8,049 0 0 0 135,166

American Samoa 0 0 0 0 0 0 0

Arizona 3,403,868 14,319 1,729 113,300 0 675,445 2,599,075

Arkansas 845,459 11,365 8,930 85,674 52,858 0 686,632

California 24,372,007 29,816 49,813 1,008,796 1,303,622 1,088,908 20,891,052

Colorado 3,219,993 8,226 15,710 31,000 128,361 0 3,036,696

Connecticut 1,497,295 1,004 6,620 17,500 94,362 0 1,377,809

Delaware 484,765 4,383 0 34,878 0 0 445,504

District of Columbia 783,055 0 0 0 0 0 783,055

Florida 11,889,692 31,802 7,075 1,732,771 31,152 7,266,168 2,820,724

Georgia 4,397,366 9,885 12,463 39,543 211,034 163,688 3,960,753

Guam 100,001 0 0 0 0 100,001 0

Hawaii 854,836 4,958 0 63,155 0 786,723 0

Idaho 280,917 5,329 1,237 88,351 0 0 186,000

Illinois 5,680,520 22,938 20,358 71,451 364,550 405,228 4,795,996

Indiana 2,277,440 14,331 9,489 216,877 70,123 113,400 1,853,220

Iowa 805,109 14,756 7,369 146,216 81,086 0 555,682

Kansas 1,331,673 6,004 14,995 41,348 11,025 0 1,258,301

Kentucky 1,962,150 0 17,056 0 258,661 85,697 1,600,737

Louisiana 2,049,851 22,928 7,429 115,495 69,144 663,655 1,171,200

Maine 132,909 724 7,600 0 11,025 0 113,560

Maryland 3,874,592 6,534 7,390 64,801 13,200 249,600 3,533,067

Massachusetts 5,202,826 10,300 12,914 130,449 249,899 159,180 4,640,084

Michigan 4,826,722 12,746 12,269 97,711 130,537 283,846 4,289,613

Minnesota 1,400,744 10,862 7,501 300,404 148,200 0 933,777

Mississippi 424,022 31,538 0 49,302 0 0 343,182

Missouri 2,793,981 11,698 13,341 97,715 77,092 223,971 2,370,164

Montana 112,643 3,104 6,168 0 0 0 103,371

N. Mariana Islands 0 0 0 0 0 0 0

Navajo Nation 21,873 3,629 0 18,244 0 0 0

Nebraska 743,335 4,946 2,500 21,000 0 0 714,889

Nevada 1,908,764 6,832 237 0 56,000 0 1,845,695

New Hampshire 165,859 950 1,595 0 11,250 0 152,064

New Jersey 4,449,920 10,749 0 91,759 118,127 115,378 4,113,907

New Mexico 568,968 7,769 2,846 105,000 0 453,353 0

New York 12,173,772 8,634 35,158 248,594 225,437 1,682,822 9,973,127

North Carolina 3,220,020 15,311 26,493 111,438 311,061 108,666 2,647,052

North Dakota 92,952 1,099 1,254 0 90,599 0 0

Ohio 5,968,446 21,415 12,060 300,293 263,264 123,850 5,247,564

Oklahoma 1,432,777 6,402 25,003 15,435 128,486 0 1,257,451

Oregon 1,505,465 7,740 18,036 0 123,120 0 1,356,569

Pennsylvania 5,612,428 14,708 33,537 0 390,681 0 5,173,502

Puerto Rico 3,794,459 4,955 17,083 112,793 220,732 0 3,438,896

Rhode Island 613,600 355 0 0 61,709 0 551,536

South Carolina 1,604,882 8,549 10,201 53,122 181,122 0 1,351,888

South Dakota 152,210 811 3,162 0 20,237 0 128,000

Tennessee 2,104,138 8,587 31,013 66,568 371,290 687,096 939,584

Texas 14,372,970 60,963 89,693 228,445 691,230 1,253,442 12,049,197

Utah 1,362,703 8,500 9,345 24,000 160,956 0 1,159,902

Vermont 63,618 298 11,570 0 51,750 0 0

Virgin Islands 50 50 0 0 0 0 0

Virginia 3,377,005 3,451 21,232 0 143,889 0 3,208,433

Washington 2,706,556 15,667 6,360 404,649 93,417 374,556 1,811,906

West Virginia 434,635 424 26,216 0 78,231 0 329,764

Wisconsin 1,507,678 17,221 0 133,000 82,035 205,247 1,070,175

Wyoming 68,027 0 8,043 0 59,984 0 0

Tribes - Region 1 0 0 0 0 0 0 0

Tribes - Region 5 0 0 0 0 0 0 0

Tribes - Region 6 1,450 1,450 0 0 0 0 0

Tribes - Region 8 0 0 0 0 0 0 0

Tribes - Region 9 2,722 0 2,722 0 0 0 0

Total 157,219,620 548,364 660,557 6,584,184 7,444,830 17,269,919 124,711,765 1

 The UCMR data are not representative at the state-level.

State 1

Total 

Population 

Served

Pop. Served by Small Systems 

(serving ≤10,000 people)

Pop. Served by Large Systems 

(serving 10,001 - 100,000 people)

Pop. Served by Very Large Systems 

(serving >100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 49 of 50

Table B25. NPYR - UCMR 2 Screening Survey Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 270 20 4 2 3 5 0 6

Alaska 97 9 1 7 0 0 0 1

American Samoa 0 0 0 0 0 0 0 0

Arizona 753 19 4 2 3 0 1 9

Arkansas 116 13 3 3 2 2 0 3

California 4,394 154 13 28 19 22 8 64

Colorado 319 26 3 9 1 3 0 10

Connecticut 165 12 3 1 1 2 0 5

Delaware 117 5 1 0 1 0 0 3

District of Columbia 8 1 0 0 0 0 0 1

Florida 793 79 11 1 31 1 23 12

Georgia 315 31 6 5 2 5 1 12

Guam 233 1 0 0 0 0 1 0

Hawaii 161 4 1 0 1 0 2 0

Idaho 109 9 3 3 2 0 0 1

Illinois 392 35 7 5 4 8 3 8

Indiana 203 21 5 2 5 2 1 6

Iowa 130 15 5 2 3 2 0 3

Kansas 140 16 3 5 1 1 0 6

Kentucky 156 17 0 4 0 8 1 4

Louisiana 302 22 8 2 3 2 3 4

Maine 39 6 2 2 0 1 0 1

Maryland 120 13 3 3 2 1 1 3

Massachusetts 221 24 4 2 4 5 1 8

Michigan 255 23 9 2 2 3 2 5

Minnesota 103 18 6 1 7 2 0 2

Mississippi 114 15 10 0 3 0 0 2

Missouri 167 20 6 4 3 2 1 4

Montana 48 7 2 4 0 0 0 1

N. Mariana Islands 0 0 0 0 0 0 0 0

Navajo Nation 30 3 2 0 1 0 0 0

Nebraska 71 7 3 1 1 0 0 2

Nevada 147 8 2 1 0 1 0 4

New Hampshire 31 6 3 1 0 1 0 1

New Jersey 375 26 6 0 4 4 1 11

New Mexico 132 8 3 2 2 0 1 0

New York 1,540 53 8 14 6 6 5 14

North Carolina 355 35 7 5 3 7 1 12

North Dakota 28 4 1 2 0 1 0 0

Ohio 297 36 7 5 7 6 1 10

Oklahoma 158 19 3 9 1 3 0 3

Oregon 147 17 3 6 0 3 0 5

Pennsylvania 656 51 10 14 0 9 0 18

Puerto Rico 569 27 2 10 2 5 0 8

Rhode Island 30 4 1 0 0 1 0 2

South Carolina 140 16 3 3 1 4 0 5

South Dakota 62 9 2 5 0 1 0 1

Tennessee 226 23 1 7 2 8 1 4

Texas 1,627 96 23 27 6 15 1 24

Utah 200 16 2 3 1 3 0 7

Vermont 36 5 1 3 0 1 0 0

Virgin Islands 4 1 1 0 0 0 0 0

Virginia 285 27 4 7 0 5 0 11

Washington 350 29 8 4 8 3 2 4

West Virginia 86 12 1 7 0 2 0 2

Wisconsin 214 17 8 0 3 2 1 3

Wyoming 33 4 0 3 0 1 0 0

Tribes - Region 1 0 0 0 0 0 0 0 0

Tribes - Region 5 0 0 0 0 0 0 0 0

Tribes - Region 6 8 2 2 0 0 0 0 0

Tribes - Region 8 0 0 0 0 0 0 0 0

Tribes - Region 9 24 2 0 2 0 0 0 0

Total 18,101 1,198 240 240 151 169 63 335 1

 The UCMR data are not representative at the state-level.

Number of Very Large Systems 

(serving >100,000 people)

State 1

Total 

Number of 

Samples

Total 

Number of 

Systems

Number of Small Systems 

(serving ≤10,000 people)

Number of Large Systems 

(serving 10,001 - 100,000 people)
EPA-OGWDW

Appendix B. Summary of Systems and Population Served by State

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 50 of 50

Table B25. NPYR - UCMR 2 Screening Survey Data - Number of Systems and Population Served by State

Ground Water Surface Water Ground Water Surface Water Ground Water Surface Water

Alabama 2,040,600 17,259 9,693 103,109 204,295 0 1,706,245

Alaska 143,305 90 8,049 0 0 0 135,166

American Samoa 0 0 0 0 0 0 0

Arizona 3,403,868 14,319 1,729 113,300 0 675,445 2,599,075

Arkansas 845,459 11,365 8,930 85,674 52,858 0 686,632

California 24,372,007 29,816 49,813 1,008,796 1,303,622 1,088,908 20,891,052

Colorado 3,219,993 8,226 15,710 31,000 128,361 0 3,036,696

Connecticut 1,497,295 1,004 6,620 17,500 94,362 0 1,377,809

Delaware 484,765 4,383 0 34,878 0 0 445,504

District of Columbia 783,055 0 0 0 0 0 783,055

Florida 11,889,692 31,802 7,075 1,732,771 31,152 7,266,168 2,820,724

Georgia 4,397,366 9,885 12,463 39,543 211,034 163,688 3,960,753

Guam 100,001 0 0 0 0 100,001 0

Hawaii 854,836 4,958 0 63,155 0 786,723 0

Idaho 280,917 5,329 1,237 88,351 0 0 186,000

Illinois 5,680,520 22,938 20,358 71,451 364,550 405,228 4,795,996

Indiana 2,277,440 14,331 9,489 216,877 70,123 113,400 1,853,220

Iowa 805,109 14,756 7,369 146,216 81,086 0 555,682

Kansas 1,331,673 6,004 14,995 41,348 11,025 0 1,258,301

Kentucky 1,962,150 0 17,056 0 258,661 85,697 1,600,737

Louisiana 2,049,851 22,928 7,429 115,495 69,144 663,655 1,171,200

Maine 132,909 724 7,600 0 11,025 0 113,560

Maryland 3,874,592 6,534 7,390 64,801 13,200 249,600 3,533,067

Massachusetts 5,202,826 10,300 12,914 130,449 249,899 159,180 4,640,084

Michigan 4,826,722 12,746 12,269 97,711 130,537 283,846 4,289,613

Minnesota 1,400,744 10,862 7,501 300,404 148,200 0 933,777

Mississippi 424,022 31,538 0 49,302 0 0 343,182

Missouri 2,793,981 11,698 13,341 97,715 77,092 223,971 2,370,164

Montana 112,643 3,104 6,168 0 0 0 103,371

N. Mariana Islands 0 0 0 0 0 0 0

Navajo Nation 21,873 3,629 0 18,244 0 0 0

Nebraska 743,335 4,946 2,500 21,000 0 0 714,889

Nevada 1,908,764 6,832 237 0 56,000 0 1,845,695

New Hampshire 165,859 950 1,595 0 11,250 0 152,064

New Jersey 4,449,920 10,749 0 91,759 118,127 115,378 4,113,907

New Mexico 568,968 7,769 2,846 105,000 0 453,353 0

New York 12,173,772 8,634 35,158 248,594 225,437 1,682,822 9,973,127

North Carolina 3,220,020 15,311 26,493 111,438 311,061 108,666 2,647,052

North Dakota 92,952 1,099 1,254 0 90,599 0 0

Ohio 5,968,446 21,415 12,060 300,293 263,264 123,850 5,247,564

Oklahoma 1,432,777 6,402 25,003 15,435 128,486 0 1,257,451

Oregon 1,505,465 7,740 18,036 0 123,120 0 1,356,569

Pennsylvania 5,612,428 14,708 33,537 0 390,681 0 5,173,502

Puerto Rico 3,794,459 4,955 17,083 112,793 220,732 0 3,438,896

Rhode Island 613,600 355 0 0 61,709 0 551,536

South Carolina 1,604,882 8,549 10,201 53,122 181,122 0 1,351,888

South Dakota 152,210 811 3,162 0 20,237 0 128,000

Tennessee 2,104,138 8,587 31,013 66,568 371,290 687,096 939,584

Texas 14,372,970 60,963 89,693 228,445 691,230 1,253,442 12,049,197

Utah 1,362,703 8,500 9,345 24,000 160,956 0 1,159,902

Vermont 63,618 298 11,570 0 51,750 0 0

Virgin Islands 50 50 0 0 0 0 0

Virginia 3,377,005 3,451 21,232 0 143,889 0 3,208,433

Washington 2,706,556 15,667 6,360 404,649 93,417 374,556 1,811,906

West Virginia 434,635 424 26,216 0 78,231 0 329,764

Wisconsin 1,507,678 17,221 0 133,000 82,035 205,247 1,070,175

Wyoming 68,027 0 8,043 0 59,984 0 0

Tribes - Region 1 0 0 0 0 0 0 0

Tribes - Region 5 0 0 0 0 0 0 0

Tribes - Region 6 1,450 1,450 0 0 0 0 0

Tribes - Region 8 0 0 0 0 0 0 0

Tribes - Region 9 2,722 0 2,722 0 0 0 0

Total 157,219,620 548,364 660,557 6,584,184 7,444,830 17,269,919 124,711,765 1

 The UCMR data are not representative at the state-level.

State 1

Total 

Population 

Served

Pop. Served by Small Systems 

(serving ≤10,000 people)

Pop. Served by Large Systems 

(serving 10,001 - 100,000 people)

Pop. Served by Very Large Systems 

(serving >100,000 people)
EPA-OGWDW Occurrence Data from the UCMR 2 - DRAFT April 2014

Appendix C

Table C1. RDX – Final UCMR 2 Assessment Monitoring Data – Summary of Samples and 

Detected Concentrations

Table C2. Terbufos Sulfone – Final UCMR 2 Assessment Monitoring Data – Summary of 

Samples and Detected Concentrations

Table C3. Acetochlor ESA – Final UCMR 2 Screening Survey Data – Summary of Samples and 

Detected Concentrations

Table C4. Alachlor ESA – Final UCMR 2 Screening Survey Data – Summary of Samples and 

Detected Concentrations

Table C5. Metolachlor – Final UCMR 2 Screening Survey Data – Summary of Samples and 

Detected Concentrations

Table C6. Metolachlor ESA – Final UCMR 2 Screening Survey Data – Summary of Samples and 

Detected Concentrations

Table C7. Metolachlor OA – Final UCMR 2 Screening Survey Data – Summary of Samples and 

Detected Concentrations

Table C8. NDBA – Final UCMR 2 Screening Survey Data – Summary of Samples and Detected 

Concentrations

Table C9. NDEA – Final UCMR 2 Screening Survey Data – Summary of Samples and Detected 

Concentrations

Table C10. NDMA – Final UCMR 2 Screening Survey Data – Summary of Samples and 

Detected Concentrations

Table C11. NMEA – Final UCMR 2 Screening Survey Data – Summary of Samples and 

Detected Concentrations

Table C12. NPYR – Final UCMR 2 Screening Survey Data – Summary of Samples and Detected 

Concentrations
EPA-OGWDW

Appendix C. Summary of Samples (Relative to the HRL)

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 1 of 24

Number Percent Number Percent Number Percent

Ground Water 2,332 0 0.00% 0 0.00% 0 0.00%

Surface Water 919 0 0.00% 0 0.00% 0 0.00%

All Small Systems 3,251 0 0.00% 0 0.00% 0 0.00%

Ground Water 11,760 0 0.00% 0 0.00% 0 0.00%

Surface Water 10,327 4 0.04% 0 0.00% 0 0.00%

All Large Systems 22,087 4 0.02% 0 0.00% 0 0.00%

Ground Water 2,012 0 0.00% 0 0.00% 0 0.00%

Surface Water 4,800 0 0.00% 0 0.00% 0 0.00%

All Very Large Systems 6,812 0 0.00% 0 0.00% 0 0.00%

All Water Systems 32,150 4 0.01% 0 0.00% 0 0.00%

Source Water Type

Samples with Detections 

> 1⁄2 HRL (10.5 μg/L)

Samples with Detections 

> HRL (21 μg/L) Samples with Detections

Total Number 

of Samples

Table C1a. RDX – UCMR 2 Assessment Monitoring Data – Summary of Samples

Sample of Small Systems (serving ≤ 10,000 people)

All Systems

Census of Very Large Systems (serving > 100,000 people)

Census of Large Systems (serving 10,001 - 100,000 people)
EPA-OGWDW

Appendix C. Summary of Samples (Relative to the HRL)

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 2 of 24

Minimum Median 90th Percentile 99th Percentile Maximum

Ground Water ND ND ND ND ND

Surface Water ND ND ND ND ND

All Small Systems ND ND ND ND ND

Ground Water ND ND ND ND ND

Surface Water 1 1.1 1.1 1.1 1.1

All Large Systems 1 1.1 1.1 1.1 1.1

Ground Water ND ND ND ND ND

Surface Water ND ND ND ND ND

All Very Large Systems ND ND ND ND ND

All Water Systems 1 1.1 1.1 1.1 1.1

ND = No detection

Source Water Type

All Systems

Concentration Value of Detections (μg/L)

Table C1b. RDX – UCMR 2 Assessment Monitoring Data – Summary of Detected 

Concentrations

Sample of Small Systems (serving ≤ 10,000 people)

Census of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)
EPA-OGWDW

Appendix C. Summary of Samples (Relative to the HRL)

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 3 of 24

Number Percent Number Percent Number Percent

Ground Water 2,328 0 0.00% 0 0.00% 0 0.00%

Surface Water 920 0 0.00% 0 0.00% 0 0.00%

All Small Systems 3,248 0 0.00% 0 0.00% 0 0.00%

Ground Water 11,760 1 0.01% 1 0.01% 1 0.01%

Surface Water 10,331 0 0.00% 0 0.00% 0 0.00%

All Large Systems 22,091 1 0.005% 1 0.005% 1 0.005%

Ground Water 2,014 0 0.00% 0 0.00% 0 0.00%

Surface Water 4,796 0 0.00% 0 0.00% 0 0.00%

All Very Large Systems 6,810 0 0.00% 0 0.00% 0 0.00%

All Water Systems 32,149 1 0.003% 1 0.003% 1 0.003%

Source Water Type Total Number 

of Samples

Samples with Detections Samples with Detections 

> 1⁄2 HRL (0.175 μg/L)

Samples with Detections 

> HRL (0.35 μg/L)

Table C2a. Terbufos Sulfone – UCMR 2 Assessment Monitoring Data – Summary of Samples

All Systems

Sample of Small Systems (serving ≤ 10,000 people)

Census of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)
EPA-OGWDW

Appendix C. Summary of Samples (Relative to the HRL)

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 4 of 24

Minimum Median 90th Percentile 99th Percentile Maximum

Ground Water ND ND ND ND ND

Surface Water ND ND ND ND ND

All Small Systems ND ND ND ND ND

Ground Water 0.42 0.42 0.42 0.42 0.42

Surface Water ND ND ND ND ND

All Large Systems 0.42 0.42 0.42 0.42 0.42

Ground Water ND ND ND ND ND

Surface Water ND ND ND ND ND

All Very Large Systems ND ND ND ND ND

All Water Systems 0.42 0.42 0.42 0.42 0.42

ND = No detection

Concentration Value of Detections (μg/L)

Source Water Type

Table C2b. Terbufos Sulfone – UCMR 2 Assessment Monitoring Data – Summary of 

Detected Concentrations

All Systems

Sample of Small Systems (serving ≤ 10,000 people)

Census of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)
EPA-OGWDW

Appendix C. Summary of Samples (Relative to the HRL)

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 5 of 24

Number Percent Number Percent Number Percent

Ground Water 786 0 0.00% 0 0.00% 0 0.00%

Surface Water 1,035 1 0.10% 1 0.10% 1 0.10%

All Small Systems 1,821 1 0.05% 1 0.05% 1 0.05%

Ground Water 1,381 0 0.00% 0 0.00% 0 0.00%

Surface Water 1,170 0 0.00% 0 0.00% 0 0.00%

All Large Systems 2,551 0 0.00% 0 0.00% 0 0.00%

Ground Water 1,999 0 0.00% 0 0.00% 0 0.00%

Surface Water 4,786 1 0.02% 1 0.02% 1 0.02%

All Very Large Systems 6,785 1 0.01% 1 0.01% 1 0.01%

All Water Systems 11,157 2 0.02% 2 0.02% 2 0.02%

Source Water Type Total Number 

of Samples

Samples with Detections Samples with Detections 

> 1⁄2 HRL (0.5 μg/L)

Samples with Detections 

> HRL (1 μg/L)

Census of Very Large Systems (serving > 100,000 people)

Table C3a. Acetochlor ESA – UCMR 2 Screening Survey Data – Summary of Samples

All Systems

Sample of Small Systems (serving ≤ 10,000 people)

Sample of Large Systems (serving 10,001 - 100,000 people)
EPA-OGWDW

Appendix C. Summary of Samples (Relative to the HRL)

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 6 of 24

Minimum Median 90th Percentile 99th Percentile Maximum

Ground Water ND ND ND ND ND

Surface Water 1.10526 1.10526 1.10526 1.10526 1.10526

All Small Systems 1.10526 1.10526 1.10526 1.10526 1.10526

Ground Water ND ND ND ND ND

Surface Water ND ND ND ND ND

All Large Systems ND ND ND ND ND

Ground Water ND ND ND ND ND

Surface Water 1.2 1.2 1.2 1.2 1.2

All Very Large Systems 1.2 1.2 1.2 1.2 1.2

All Water Systems 1.10526 1.15263 1.19053 1.19905 1.2

ND = No detection

Source Water Type

Table C3b. Acetochlor ESA – UCMR 2 Screening Survey Data – Summary of Detected 

Concentrations

All Systems

Sample of Small Systems (serving ≤ 10,000 people)

Sample of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)

Concentration Value of Detections (μg/L)
EPA-OGWDW

Appendix C. Summary of Samples (Relative to the HRL)

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 7 of 24

Number Percent Number Percent Number Percent

Ground Water 786 0 0.00% 0 0.00% 0 0.00%

Surface Water 1,035 3 0.29% 3 0.29% 3 0.29%

All Small Systems 1,821 3 0.16% 3 0.16% 3 0.16%

Ground Water 1,381 1 0.07% 1 0.07% 1 0.07%

Surface Water 1,170 0 0.00% 0 0.00% 0 0.00%

All Large Systems 2,551 1 0.04% 1 0.04% 1 0.04%

Ground Water 1,999 0 0.00% 0 0.00% 0 0.00%

Surface Water 4,785 1 0.02% 1 0.02% 1 0.02%

All Very Large Systems 6,784 1 0.01% 1 0.01% 1 0.01%

All Water Systems 11,156 5 0.04% 5 0.04% 5 0.04%

Source Water Type Total Number 

of Samples

Samples with Detections Samples with Detections 

> 1⁄2 HRL (0.2 μg/L)

Samples with Detections 

> HRL (0.4 μg/L)

Census of Very Large Systems (serving > 100,000 people)

Table C4a. Alachlor ESA – UCMR 2 Screening Survey Data – Summary of Samples

All Systems

Sample of Small Systems (serving ≤ 10,000 people)

Sample of Large Systems (serving 10,001 - 100,000 people)
EPA-OGWDW

Appendix C. Summary of Samples (Relative to the HRL)

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 8 of 24

Minimum Median 90th Percentile 99th Percentile Maximum

Ground Water ND ND ND ND ND

Surface Water 1 1.2 1.2 1.2 1.2

All Small Systems 1 1.2 1.2 1.2 1.2

Ground Water 1.06364 1.06364 1.06364 1.06364 1.06364

Surface Water ND ND ND ND ND

All Large Systems 1.06364 1.06364 1.06364 1.06364 1.06364

Ground Water ND ND ND ND ND

Surface Water 1.3 1.3 1.3 1.3 1.3

All Very Large Systems 1.3 1.3 1.3 1.3 1.3

All Water Systems 1 1.2 1.3 1.3 1.3

ND = No detection

Source Water Type

Table C4b. Alachlor ESA – UCMR 2 Screening Survey Data – Summary of Detected 

Concentrations

All Systems

Sample of Small Systems (serving ≤ 10,000 people)

Sample of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)

Concentration Value of Detections (μg/L)
EPA-OGWDW

Appendix C. Summary of Samples (Relative to the HRL)

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 9 of 24

Number Percent Number Percent Number Percent

Ground Water 788 0 0.00% 0 0.00% 0 0.00%

Surface Water 1,040 2 0.19% 0 0.00% 0 0.00%

All Small Systems 1,828 2 0.11% 0 0.00% 0 0.00%

Ground Water 1,392 0 0.00% 0 0.00% 0 0.00%

Surface Water 1,178 0 0.00% 0 0.00% 0 0.00%

All Large Systems 2,570 0 0.00% 0 0.00% 0 0.00%

Ground Water 2,010 0 0.00% 0 0.00% 0 0.00%

Surface Water 4,784 1 0.02% 0 0.00% 0 0.00%

All Very Large Systems 6,794 1 0.01% 0 0.00% 0 0.00%

All Water Systems 11,192 3 0.03% 0 0.00% 0 0.00%

Source Water Type Total Number 

of Samples

Samples with Detections Samples with Detections 

> 1⁄2 HRL (350 μg/L)

Samples with Detections 

> HRL (700 μg/L)

Table C5a. Metolachlor – UCMR 2 Screening Survey Data – Summary of Samples

All Systems

Sample of Small Systems (serving ≤ 10,000 people)

Sample of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)
EPA-OGWDW

Appendix C. Summary of Samples (Relative to the HRL)

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 10 of 24

Minimum Median 90th Percentile 99th Percentile Maximum

Ground Water ND ND ND ND ND

Surface Water 1.152 1.94218 2.57432 2.71655 2.73235

All Small Systems 1.152 1.94218 2.57432 2.71655 2.73235

Ground Water ND ND ND ND ND

Surface Water ND ND ND ND ND

All Large Systems ND ND ND ND ND

Ground Water ND ND ND ND ND

Surface Water 1.4 1.4 1.4 1.4 1.4

All Very Large Systems 1.4 1.4 1.4 1.4 1.4

All Water Systems 1.152 1.4 2.46588 2.7057 2.73235

ND = No detection

Concentration Value of Detections (μg/L)

Source Water Type

Table C5b. Metolachlor – UCMR 2 Screening Survey Data – Summary of Detected 

Concentrations

All Systems

Sample of Small Systems (serving ≤ 10,000 people)

Sample of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)
EPA-OGWDW

Appendix C. Summary of Samples (Relative to the HRL)

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 11 of 24

Number Percent Number Percent Number Percent

Ground Water 786 16 2.04% 0 0.00% 0 0.00%

Surface Water 1,035 5 0.48% 0 0.00% 0 0.00%

All Small Systems 1,821 21 1.15% 0 0.00% 0 0.00%

Ground Water 1,381 4 0.29% 0 0.00% 0 0.00%

Surface Water 1,170 8 0.68% 0 0.00% 0 0.00%

All Large Systems 2,551 12 0.47% 0 0.00% 0 0.00%

Ground Water 1,999 9 0.45% 0 0.00% 0 0.00%

Surface Water 4,786 10 0.21% 0 0.00% 0 0.00%

All Very Large Systems 6,785 19 0.28% 0 0.00% 0 0.00%

All Water Systems 11,157 52 0.47% 0 0.00% 0 0.00%

Source Water Type Total Number 

of Samples

Samples with Detections Samples with Detections 

> 1⁄2 HRL (350 μg/L)

Samples with Detections 

> HRL (700 μg/L)

Census of Very Large Systems (serving > 100,000 people)

Table C6a. Metolachlor ESA – UCMR 2 Screening Survey Data – Summary of Samples

All Systems

Sample of Small Systems (serving ≤ 10,000 people)

Sample of Large Systems (serving 10,001 - 100,000 people)
EPA-OGWDW

Appendix C. Summary of Samples (Relative to the HRL)

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 12 of 24

Minimum Median 90th Percentile 99th Percentile Maximum

Ground Water 1.16 1.95 2.71137 3.78137 3.95455

Surface Water 1.02381 1.11739 1.4 1.4 1.4

All Small Systems 1.02381 1.8375 2.62273 3.72364 3.95455

Ground Water 1.48261 1.87095 2.13864 2.20614 2.21364

Surface Water 1 1.1 1.3 1.3 1.3

All Large Systems 1 1.25 1.9451 2.18614 2.21364

Ground Water 1.03 1.168 3.024 3.296 3.326

Surface Water 1.1 1.2 2.0 2.2 2.2

All Very Large Systems 1.03 1.188 2.711 3.258 3.326

All Water Systems 1 1.44131 2.61986 3.63399 3.95455

Source Water Type

Table C6b. Metolachlor ESA – UCMR 2 Screening Survey Data – Summary of Detected 

Concentrations

All Systems

Sample of Small Systems (serving ≤ 10,000 people)

Sample of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)

Concentration Value of Detections (μg/L)
EPA-OGWDW

Appendix C. Summary of Samples (Relative to the HRL)

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 13 of 24

Number Percent Number Percent Number Percent

Ground Water 786 0 0.00% 0 0.00% 0 0.00%

Surface Water 1,035 0 0.00% 0 0.00% 0 0.00%

All Small Systems 1,821 0 0.00% 0 0.00% 0 0.00%

Ground Water 1,381 0 0.00% 0 0.00% 0 0.00%

Surface Water 1,170 0 0.00% 0 0.00% 0 0.00%

All Large Systems 2,551 0 0.00% 0 0.00% 0 0.00%

Ground Water 1,999 3 0.15% 0 0.00% 0 0.00%

Surface Water 4,786 0 0.00% 0 0.00% 0 0.00%

All Very Large Systems 6,785 3 0.04% 0 0.00% 0 0.00%

All Water Systems 11,157 3 0.03% 0 0.00% 0 0.00%

Source Water Type Total Number 

of Samples

Samples with Detections Samples with Detections 

> 1⁄2 HRL (700 μg/L)

Samples with Detections 

> HRL (700 μg/L)

Census of Very Large Systems (serving > 100,000 people)

Table C7a. Metolachlor OA – UCMR 2 Screening Survey Data – Summary of Samples

All Systems

Sample of Small Systems (serving ≤ 10,000 people)

Sample of Large Systems (serving 10,001 - 100,000 people)
EPA-OGWDW

Appendix C. Summary of Samples (Relative to the HRL)

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 14 of 24

Minimum Median 90th Percentile 99th Percentile Maximum

Ground Water ND ND ND ND ND

Surface Water ND ND ND ND ND

All Small Systems ND ND ND ND ND

Ground Water ND ND ND ND ND

Surface Water ND ND ND ND ND

All Large Systems ND ND ND ND ND

Ground Water 2.502 3.078 3.447 3.53 3.539

Surface Water ND ND ND ND ND

All Very Large Systems 2.502 3.078 3.447 3.53 3.539

All Water Systems 2.502 3.078 3.447 3.53 3.539

ND = No detection

Source Water Type

Table C7b. Metolachlor OA – UCMR 2 Screening Survey Data – Summary of Detected 

Concentrations

All Systems

Sample of Small Systems (serving ≤ 10,000 people)

Sample of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)

Concentration Value of Detections (μg/L)
EPA-OGWDW

Appendix C. Summary of Samples (Relative to the HRL)

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 15 of 24

Number Percent Number Percent Number Percent

Ground Water 1,237 3 0.24% 1 0.08% 0 0.00%

Surface Water 1,996 0 0.00% 0 0.00% 0 0.00%

All Small Systems 3,233 3 0.09% 1 0.03% 0 0.00%

Ground Water 1,932 0 0.00% 0 0.00% 0 0.00%

Surface Water 2,091 0 0.00% 0 0.00% 0 0.00%

All Large Systems 4,023 0 0.00% 0 0.00% 0 0.00%

Ground Water 2,966 3 0.10% 0 0.00% 0 0.00%

Surface Water 7,879 3 0.04% 0 0.00% 0 0.00%

All Very Large Systems 10,845 6 0.06% 0 0.00% 0 0.00%

All Water Systems 18,101 9 0.05% 1 0.01% 0 0.00%

Source Water Type Total Number 

of Samples

Samples with Detections Samples with Detections 

> 1⁄2 HRL (0.015 μg/L)

Samples with Detections 

> HRL (0.03 μg/L)

Table C8a. NDBA – UCMR 2 Screening Survey Data – Summary of Samples

All Systems

Sample of Large Systems (serving 10,001 - 100,000 people)

Sample of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)
EPA-OGWDW

Appendix C. Summary of Samples (Relative to the HRL)

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 16 of 24

Minimum Median 90th Percentile 99th Percentile Maximum

Ground Water 0.004 0.00629 0.01775 0.02033 0.02062

Surface Water ND ND ND ND ND

All Small Systems 0.004 0.00629 0.01775 0.02033 0.02062

Ground Water ND ND ND ND ND

Surface Water ND ND ND ND ND

All Large Systems ND ND ND ND ND

Ground Water 0.00442 0.00666 0.00877 0.00925 0.0093

Surface Water 0.0048 0.0092 0.0098 0.01 0.01

All Very Large Systems 0.00442 0.00793 0.00965 0.00997 0.01

All Water Systems 0.004 0.00666 0.01212 0.01977 0.02062

ND = No detection

Concentration Value of Detections (μg/L)

Source Water Type

Table C8b. NDBA – UCMR 2 Screening Survey Data – Summary of Detected 

Concentrations

All Systems

Sample of Small Systems (serving ≤ 10,000 people)

Sample of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)
EPA-OGWDW

Appendix C. Summary of Samples (Relative to the HRL)

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 17 of 24

Number Percent Number Percent Number Percent

Ground Water 1,237 1 0.08% 1 0.08% 1 0.08%

Surface Water 1,996 0 0.00% 0 0.00% 0 0.00%

All Small Systems 3,233 1 0.03% 1 0.03% 1 0.03%

Ground Water 1,920 3 0.16% 3 0.16% 3 0.16%

Surface Water 2,091 6 0.29% 6 0.29% 6 0.29%

All Large Systems 4,011 9 0.22% 9 0.22% 9 0.22%

Ground Water 2,968 7 0.24% 7 0.24% 7 0.24%

Surface Water 7,884 29 0.37% 29 0.37% 29 0.37%

All Very Large Systems 10,852 36 0.33% 36 0.33% 36 0.33%

All Water Systems 18,096 46 0.25% 46 0.25% 46 0.25%

Source Water Type Total Number 

of Samples

Samples with Detections Samples with Detections 

> 1⁄2 HRL (0.0002 μg/L)

Samples with Detections 

> HRL (0.0004 μg/L)

Table C9a. NDEA – UCMR 2 Screening Survey Data – Summary of Samples

All Systems

Sample of Small Systems (serving ≤ 10,000 people)

Sample of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)
EPA-OGWDW

Appendix C. Summary of Samples (Relative to the HRL)

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 18 of 24

Minimum Median 90th Percentile 99th Percentile Maximum

Ground Water 0.009 0.009 0.009 0.009 0.009

Surface Water ND ND ND ND ND

All Small Systems 0.009 0.009 0.009 0.009 0.009

Ground Water 0.0051 0.0052 0.0061 0.0063 0.0063

Surface Water 0.0057 0.012 0.0435 0.0494 0.05

All Large Systems 0.0051 0.0086 0.0396 0.049 0.05

Ground Water 0.0053 0.0061 0.0126 0.0211 0.022

Surface Water 0.005 0.008 0.029 0.096 0.1

All Very Large Systems 0.005 0.007 0.027 0.095 0.1

All Water Systems 0.005 0.007 0.031 0.093 0.1

ND = No detection

Concentration Value of Detections (μg/L)

Source Water Type

Table C9b. NDEA – UCMR 2 Screening Survey Data – Summary of Detected 

Concentrations

All Systems

Sample of Small Systems (serving ≤ 10,000 people)

Sample of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)
EPA-OGWDW

Appendix C. Summary of Samples (Relative to the HRL)

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 19 of 24

Number Percent Number Percent Number Percent

Ground Water 1,237 14 1.13% 14 1.13% 14 1.13%

Surface Water 1,996 326 16.33% 326 16.33% 326 16.33%

All Small Systems 3,233 340 10.52% 340 10.52% 340 10.52%

Ground Water 1,932 48 2.48% 48 2.48% 48 2.48%

Surface Water 2,091 305 14.59% 305 14.59% 305 14.59%

All Large Systems 4,023 353 8.77% 353 8.77% 353 8.77%

Ground Water 2,966 52 1.75% 52 1.75% 52 1.75%

Surface Water 7,876 1,116 14.17% 1,116 14.17% 1,116 14.17%

All Very Large Systems 10,842 1,168 10.77% 1,168 10.77% 1,168 10.77%

All Water Systems 18,098 1,861 10.28% 1,861 10.28% 1,861 10.28%

Source Water Type Total Number 

of Samples

Samples with Detections Samples with Detections 

> 1⁄2 HRL (0.0003 μg/L)

Samples with Detections 

> HRL (0.0006 μg/L)

Table C10a. NDMA – UCMR 2 Screening Survey Data – Summary of Samples

All Systems

Sample of Small Systems (serving ≤ 10,000 people)

Sample of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)
EPA-OGWDW

Appendix C. Summary of Samples (Relative to the HRL)

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 20 of 24

Minimum Median 90th Percentile 99th Percentile Maximum

Ground Water 0.002 0.0036 0.0075 0.0092 0.0094

Surface Water 0.002 0.006 0.032 0.125 0.63

All Small Systems 0.002 0.006 0.031 0.122 0.63

Ground Water 0.002 0.004 0.005 0.01 0.01

Surface Water 0.002 0.0045 0.016 0.0523 0.0656

All Large Systems 0.002 0.0041 0.0152 0.0477 0.0656

Ground Water 0.002 0.00297 0.00522 0.01073 0.01343

Surface Water 0.002 0.004 0.015 0.043 0.094

All Very Large Systems 0.002 0.004 0.014 0.042 0.094

All Water Systems 0.002 0.004 0.016 0.063 0.63

Concentration Value of Detections (μg/L)

Source Water Type

Table C10b. NDMA – UCMR 2 Screening Survey Data – Summary of Detected 

Concentrations

All Systems

Sample of Small Systems (serving ≤ 10,000 people)

Sample of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)
EPA-OGWDW

Appendix C. Summary of Samples (Relative to the HRL)

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 21 of 24

Number Percent Number Percent Number Percent

Ground Water 1,237 0 0.00% 0 0.00% 0 0.00%

Surface Water 1,996 3 0.15% 3 0.15% 3 0.15%

All Small Systems 3,233 3 0.09% 3 0.09% 3 0.09%

Ground Water 1,932 0 0.00% 0 0.00% 0 0.00%

Surface Water 2,091 0 0.00% 0 0.00% 0 0.00%

All Large Systems 4,023 0 0.00% 0 0.00% 0 0.00%

Ground Water 2,966 0 0.00% 0 0.00% 0 0.00%

Surface Water 7,879 0 0.00% 0 0.00% 0 0.00%

All Very Large Systems 10,845 0 0.00% 0 0.00% 0 0.00%

All Water Systems 18,101 3 0.02% 3 0.02% 3 0.02%

Source Water Type Total Number 

of Samples

Samples with Detections Samples with Detections 

> 1⁄2 HRL (0.0015 μg/L)

Samples with Detections 

> HRL (0.003 μg/L)

Table C11a. NMEA – UCMR 2 Screening Survey Data – Summary of Samples

All Systems

Sample of Small Systems (serving ≤ 10,000 people)

Sample of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)
EPA-OGWDW

Appendix C. Summary of Samples (Relative to the HRL)

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 22 of 24

Minimum Median 90th Percentile 99th Percentile Maximum

Ground Water ND ND ND ND ND

Surface Water 0.0036 0.0045 0.0048 0.0049 0.0049

All Small Systems 0.0036 0.0045 0.0048 0.0049 0.0049

Ground Water ND ND ND ND ND

Surface Water ND ND ND ND ND

All Large Systems ND ND ND ND ND

Ground Water ND ND ND ND ND

Surface Water ND ND ND ND ND

All Very Large Systems ND ND ND ND ND

All Water Systems 0.0036 0.0045 0.0048 0.0049 0.0049

ND = No detection

Concentration Value of Detections (μg/L)

Source Water Type

Table C11b. NMEA – UCMR 2 Screening Survey Data – Summary of Detected 

Concentrations

All Systems

Sample of Small Systems (serving ≤ 10,000 people)

Sample of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)
EPA-OGWDW

Appendix C. Summary of Samples (Relative to the HRL)

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 23 of 24

Number Percent Number Percent Number Percent

Ground Water 1,237 0 0.00% 0 0.00% 0 0.00%

Surface Water 1,996 11 0.55% 11 0.55% 11 0.55%

All Small Systems 3,233 11 0.34% 11 0.34% 11 0.34%

Ground Water 1,932 0 0.00% 0 0.00% 0 0.00%

Surface Water 2,091 7 0.33% 7 0.33% 7 0.33%

All Large Systems 4,023 7 0.17% 7 0.17% 7 0.17%

Ground Water 2,966 1 0.03% 1 0.03% 1 0.03%

Surface Water 7,879 22 0.28% 22 0.28% 22 0.28%

All Very Large Systems 10,845 23 0.21% 23 0.21% 23 0.21%

All Water Systems 18,101 41 0.23% 41 0.23% 41 0.23%

Source Water Type Total Number 

of Samples

Samples with Detections Samples with Detections 

> 1⁄2 HRL (0.001 μg/L)

Samples with Detections 

> HRL (0.002 μg/L)

Table C12a. NPYR – UCMR 2 Screening Survey Data – Summary of Samples

All Systems

Sample of Small Systems (serving ≤ 10,000 people)

Sample of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)
EPA-OGWDW

Appendix C. Summary of Samples (Relative to the HRL)

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 24 of 24

Minimum Median 90th Percentile 99th Percentile Maximum

Ground Water ND ND ND ND ND

Surface Water 0.00207 0.00284 0.005 0.00599 0.0061

All Small Systems 0.00207 0.00284 0.005 0.00599 0.0061

Ground Water ND ND ND ND ND

Surface Water 0.0022 0.0054 0.0078 0.0095 0.0097

All Large Systems 0.0022 0.0054 0.0078 0.0095 0.0097

Ground Water 0.0036 0.0036 0.0036 0.0036 0.0036

Surface Water 0.0021 0.0047 0.0137 0.0224 0.0238

All Very Large Systems 0.0021 0.0045 0.0130 0.0223 0.0238

All Water Systems 0.00207 0.0039 0.0076 0.02116 0.0238

ND = No detection

Concentration Value of Detections (μg/L)

Source Water Type

Table C12b. NPYR – UCMR 2 Screening Survey Data – Summary of Detected 

Concentrations

All Systems

Sample of Small Systems (serving ≤ 10,000 people)

Sample of Large Systems (serving 10,001 - 100,000 people)

Census of Very Large Systems (serving > 100,000 people)
EPA-OGWDW Occurrence Data from the UCMR 2 - DRAFT April 2014

Appendix D

Table D1a. BDE-47 Occurrence Data from UCMR 2 Assessment Monitoring thru July 2011 -

Summary of Detected Concentrations

Table D1b. BDE-47 National Occurrence Measures Based on UCMR 2 Assessment Monitoring 

Data thru July 2011 - Summary of Samples

Table D1c. BDE-47 National Occurrence Measures Based on UCMR 2 Assessment Monitoring 

Data thru July 2011 - Summary of System and Population Served Data - All 

Detections

Table D2a. BDE-99 Occurrence Data from UCMR 2 Assessment Monitoring thru July 2011 -

Summary of Detected Concentrations

Table D2b. BDE-99 National Occurrence Measures Based on UCMR 2 Assessment Monitoring 

Data thru July 2011 - Summary of Samples

Table D2c. BDE-99 National Occurrence Measures Based on UCMR 2 Assessment Monitoring 

Data thru July 2011 - Summary of System and Population Served Data - All 

Detections

Table D3a. BDE-100 Occurrence Data from UCMR 2 Assessment Monitoring thru July 2011 -

Summary of Detected Concentrations

Table D3b. BDE-100 National Occurrence Measures Based on UCMR 2 Assessment Monitoring 

Data thru July 2011 - Summary of Samples

Table D3c. BDE-100 National Occurrence Measures Based on UCMR 2 Assessment Monitoring 

Data thru July 2011 - Summary of System and Population Served Data - All 

Detections

Table D4a. BDE-153 Occurrence Data from UCMR 2 Assessment Monitoring thru July 2011 -

Summary of Detected Concentrations

Table D4b. BDE-153 National Occurrence Measures Based on UCMR 2 Assessment Monitoring 

Data thru July 2011 - Summary of Samples

Table D4c. BDE-153 National Occurrence Measures Based on UCMR 2 Assessment Monitoring 

Data thru July 2011 - Summary of System and Population Served Data - All 

Detections

Table D5a. Dimethoate Occurrence Data from UCMR 2 Assessment Monitoring thru July 2011 -

Summary of Detected Concentrations

Table D5b. Dimethoate National Occurrence Measures Based on UCMR 2 Assessment 

Monitoring Data thru July 2011 - Summary of Samples

Table D5c. Dimethoate National Occurrence Measures Based on UCMR 2 Assessment 

Monitoring Data thru July 2011 - Summary of System and Population Served Data -

All Detections

Table D6a. 1,3-Dinitrobenzene Occurrence Data from UCMR 2 Assessment Monitoring thru 

July 2011 - Summary of Detected Concentrations

Table D6b. 1,3-Dinitrobenzene National Occurrence Measures Based on UCMR 2 Assessment 

Monitoring Data thru July 2011 - Summary of Samples
EPA-OGWDW Occurrence Data from the UCMR 2 - DRAFT April 2014

Table D6c. 1,3-Dinitrobenzene National Occurrence Measures Based on UCMR 2 Assessment 

Monitoring Data thru July 2011 - Summary of System and Population Served Data -

All Detections

Table D7a. HBB Occurrence Data from UCMR 2 Assessment Monitoring thru July 2011 -

Summary of Detected Concentrations

Table D7b. HBB National Occurrence Measures Based on UCMR 2 Assessment Monitoring 

Data thru July 2011 - Summary of Samples

Table D7c. HBB National Occurrence Measures Based on UCMR 2 Assessment Monitoring 

Data thru July 2011 - Summary of System and Population Served Data - All 

Detections

Table D8a. RDX Occurrence Data from UCMR 2 Assessment Monitoring thru July 2011 -

Summary of Detected Concentrations

Table D8b. RDX National Occurrence Measures Based on UCMR 2 Assessment Monitoring 

Data thru July 2011 - Summary of Samples

Table D8c. RDX National Occurrence Measures Based on UCMR 2 Assessment Monitoring 

Data thru July 2011 - Summary of System and Population Served Data - All 

Detections

Table D8d. RDX National Occurrence Measures Based on UCMR 2 Assessment Monitoring 

Data thru July 2011 - Summary of System and Population Served Data - Detections

> 1⁄2 HRL

Table D8e. RDX National Occurrence Measures Based on UCMR 2 Assessment Monitoring 

Data thru July 2011 - Summary of System and Population Served Data - Detections

> HRL

Table D9a. Terbufos Sulfone Occurrence Data from UCMR 2 Assessment Monitoring thru July 

2011 - Summary of Detected Concentrations

Table D9b. Terbufos Sulfone National Occurrence Measures Based on UCMR 2 Assessment 

Monitoring Data thru July 2011 - Summary of Samples

Table D9c. Terbufos Sulfone National Occurrence Measures Based on UCMR 2 Assessment 

Monitoring Data thru July 2011 - Summary of System and Population Served Data -

All Detections

Table D9d. Terbufos Sulfone National Occurrence Measures Based on UCMR 2 Assessment 

Monitoring Data thru July 2011 - Summary of System and Population Served Data -

Detections > 1⁄2 HRL

Table D9e. Terbufos Sulfone National Occurrence Measures Based on UCMR 2 Assessment 

Monitoring Data thru July 2011 - Summary of System and Population Served Data -

Detections > HRL

Table D10a. TNT Occurrence Data from UCMR 2 Assessment Monitoring thru July 2011 -

Summary of Detected Concentrations

Table D10b. TNT National Occurrence Measures Based on UCMR 2 Assessment Monitoring 

Data thru July 2011 - Summary of Samples
EPA-OGWDW Occurrence Data from the UCMR 2 - DRAFT April 2014

Table D10c. TNT National Occurrence Measures Based on UCMR 2 Assessment Monitoring 

Data thru July 2011 - Summary of System and Population Served Data - All 

Detections

Table D11a. Acetochlor Occurrence Data from UCMR 2 Screening Survey thru July 2011 -

Summary of Detected Concentrations

Table D11b. Acetochlor National Occurrence Measures Based on UCMR 2 Screening Survey

Data thru July 2011 - Summary of Samples

Table D11c. Acetochlor National Occurrence Measures Based on UCMR 2 Screening Survey

Data thru July 2011 - Summary of System and Population Served Data - All 

Detections

Table D12a. Acetochlor ESA Occurrence Data from UCMR 2 Screening Survey thru July 2011 -

Summary of Detected Concentrations

Table D12b. Acetochlor ESA National Occurrence Measures Based on UCMR 2 Screening 

Survey Data thru July 2011 - Summary of Samples

Table D12c. Acetochlor ESA National Occurrence Measures Based on UCMR 2 Screening 

Survey Data thru July 2011 - Summary of System and Population Served Data - All 

Detections

Table D12d. Acetochlor ESA National Occurrence Measures Based on UCMR 2 Screening 

Survey Data thru July 2011 - Summary of System and Population Served Data -

Detections > 1⁄2 HRL

Table D12e. Acetochlor ESA National Occurrence Measures Based on UCMR 2 Screening 

Survey Data thru July 2011 - Summary of System and Population Served Data -

Detections > HRL

Table D13a. Acetochlor OA Occurrence Data from UCMR 2 Screening Survey thru July 2011 -

Summary of Detected Concentrations

Table D13b. Acetochlor OA National Occurrence Measures Based on UCMR 2 Screening 

Survey Data thru July 2011 - Summary of Samples

Table D13c. Acetochlor OA National Occurrence Measures Based on UCMR 2 Screening 

Survey Data thru July 2011 - Summary of System and Population Served Data - All 

Detections

Table D14a. Alachlor Occurrence Data from UCMR 2 Screening Survey thru July 2011 -

Summary of Detected Concentrations

Table D14b. Alachlor National Occurrence Measures Based on UCMR 2 Screening Survey Data 

thru July 2011 - Summary of Samples

Table D14c. Alachlor National Occurrence Measures Based on UCMR 2 Screening Survey Data 

thru July 2011 - Summary of System and Population Served Data - All Detections

Table D15a. Alachlor ESA Occurrence Data from UCMR 2 Screening Survey thru July 2011 -

Summary of Detected Concentrations

Table D15b. Alachlor ESA National Occurrence Measures Based on UCMR 2 Screening Survey

Data thru July 2011 - Summary of Samples
EPA-OGWDW Occurrence Data from the UCMR 2 - DRAFT April 2014

Table D15c. Alachlor ESA National Occurrence Measures Based on UCMR 2 Screening Survey

Data thru July 2011 - Summary of System and Population Served Data - All 

Detections

Table D15d. Alachlor ESA National Occurrence Measures Based on UCMR 2 Screening Survey

Data thru July 2011 - Summary of System and Population Served Data - Detections

> 1⁄2 HRL

Table D15e. Alachlor ESA National Occurrence Measures Based on UCMR 2 Screening Survey

Data thru July 2011 - Summary of System and Population Served Data - Detections

> HRL

Table D16a. Alachlor OA Occurrence Data from UCMR 2 Screening Survey thru July 2011 -

Summary of Detected Concentrations

Table D16b. Alachlor OA National Occurrence Measures Based on UCMR 2 Screening Survey

Data thru July 2011 - Summary of Samples

Table D16c. Alachlor OA National Occurrence Measures Based on UCMR 2 Screening Survey

Data thru July 2011 - Summary of System and Population Served Data - All 

Detections

Table D17a. Metolachlor Occurrence Data from UCMR 2 Screening Survey thru July 2011 -

Summary of Detected Concentrations

Table D17b. Metolachlor National Occurrence Measures Based on UCMR 2 Screening Survey

Data thru July 2011 - Summary of Samples

Table D17c. Metolachlor National Occurrence Measures Based on UCMR 2 Screening Survey

Data thru July 2011 - Summary of System and Population Served Data - All 

Detections

Table D17d. Metolachlor National Occurrence Measures Based on UCMR 2 Screening Survey

Data thru July 2011 - Summary of System and Population Served Data - Detections

> 1⁄2 HRL

Table D17e. Metolachlor National Occurrence Measures Based on UCMR 2 Screening Survey

Data thru July 2011 - Summary of System and Population Served Data - Detections

> HRL

Table D18a. Metolachlor ESA Occurrence Data from UCMR 2 Screening Survey thru July 2011 

- Summary of Detected Concentrations

Table D18b. Metolachlor ESA National Occurrence Measures Based on UCMR 2 Screening 

Survey Data thru July 2011 - Summary of Samples

Table D18c. Metolachlor ESA National Occurrence Measures Based on UCMR 2 Screening 

Survey Data thru July 2011 - Summary of System and Population Served Data - All 

Detections

Table D18d. Metolachlor ESA National Occurrence Measures Based on UCMR 2 Screening 

Survey Data thru July 2011 - Summary of System and Population Served Data -

Detections > 1⁄2 HRL

Table D18e. Metolachlor ESA National Occurrence Measures Based on UCMR 2 Screening 

Survey Data thru July 2011 - Summary of System and Population Served Data -

Detections > HRL
EPA-OGWDW Occurrence Data from the UCMR 2 - DRAFT April 2014

Table D19a. Metolachlor OA Occurrence Data from UCMR 2 Screening Survey thru July 2011 -

Summary of Detected Concentrations

Table D19b. Metolachlor OA National Occurrence Measures Based on UCMR 2 Screening 

Survey Data thru July 2011 - Summary of Samples

Table D19c. Metolachlor OA National Occurrence Measures Based on UCMR 2 Screening 

Survey Data thru July 2011 - Summary of System and Population Served Data - All 

Detections

Table D19d. Metolachlor OA National Occurrence Measures Based on UCMR 2 Screening 

Survey Data thru July 2011 - Summary of System and Population Served Data -

Detections > 1⁄2 HRL

Table D19e. Metolachlor OA National Occurrence Measures Based on UCMR 2 Screening 

Survey Data thru July 2011 - Summary of System and Population Served Data -

Detections > HRL

Table D20a. NDBA Occurrence Data from UCMR 2 Screening Survey thru July 2011 -

Summary of Detected Concentrations

Table D20b. NDBA National Occurrence Measures Based on UCMR 2 Screening Survey Data 

thru July 2011 - Summary of Samples

Table D20c. NDBA National Occurrence Measures Based on UCMR 2 Screening Survey Data 

thru July 2011 - Summary of System and Population Served Data - All Detections

Table D20d. NDBA National Occurrence Measures Based on UCMR 2 Screening Survey Data 

thru July 2011 - Summary of System and Population Served Data - Detections > 1⁄2 

HRL

Table D20e. NDBA National Occurrence Measures Based on UCMR 2 Screening Survey Data 

thru July 2011 - Summary of System and Population Served Data - Detections > 

HRL

Table D21a. NDEA Occurrence Data from UCMR 2 Screening Survey thru July 2011 -

Summary of Detected Concentrations

Table D21b. NDEA National Occurrence Measures Based on UCMR 2 Screening Survey Data 

thru July 2011 - Summary of Samples

Table D21c. NDEA National Occurrence Measures Based on UCMR 2 Screening Survey Data 

thru July 2011 - Summary of System and Population Served Data - All Detections

Table D21d. NDEA National Occurrence Measures Based on UCMR 2 Screening Survey Data 

thru July 2011 - Summary of System and Population Served Data - Detections > 1⁄2 

HRL

Table D21e. NDEA National Occurrence Measures Based on UCMR 2 Screening Survey Data 

thru July 2011 - Summary of System and Population Served Data - Detections > 

HRL

Table D22a. NDMA Occurrence Data from UCMR 2 Screening Survey thru July 2011 -

Summary of Detected Concentrations

Table D22b. NDMA National Occurrence Measures Based on UCMR 2 Screening Survey Data 

thru July 2011 - Summary of Samples

Table D22c. NDMA National Occurrence Measures Based on UCMR 2 Screening Survey Data 

thru July 2011 - Summary of System and Population Served Data - All Detections
EPA-OGWDW Occurrence Data from the UCMR 2 - DRAFT April 2014

Table D22d. NDMA National Occurrence Measures Based on UCMR 2 Screening Survey Data 

thru July 2011 - Summary of System and Population Served Data - Detections > 1⁄2 

HRL

Table D22e. NDMA National Occurrence Measures Based on UCMR 2 Screening Survey Data 

thru July 2011 - Summary of System and Population Served Data - Detections > 

HRL

Table D23a. NDPA Occurrence Data from UCMR 2 Screening Survey thru July 2011 -

Summary of Detected Concentrations

Table D23b. NDPA National Occurrence Measures Based on UCMR 2 Screening Survey Data 

thru July 2011 - Summary of Samples

Table D23c. NDPA National Occurrence Measures Based on UCMR 2 Screening Survey Data 

thru July 2011 - Summary of System and Population Served Data - All Detections

Table D24a. NMEA Occurrence Data from UCMR 2 Screening Survey thru July 2011 -

Summary of Detected Concentrations

Table D24b. NMEA National Occurrence Measures Based on UCMR 2 Screening Survey Data 

thru July 2011 - Summary of Samples

Table D24c. NMEA National Occurrence Measures Based on UCMR 2 Screening Survey Data 

thru July 2011 - Summary of System and Population Served Data - All Detections

Table D24d. NMEA National Occurrence Measures Based on UCMR 2 Screening Survey Data 

thru July 2011 - Summary of System and Population Served Data - Detections > 1⁄2 

HRL

Table D24e. NMEA National Occurrence Measures Based on UCMR 2 Screening Survey Data 

thru July 2011 - Summary of System and Population Served Data - Detections > 

HRL

Table D25a. NPYR Occurrence Data from UCMR 2 Screening Survey thru July 2011 -

Summary of Detected Concentrations

Table D25b. NPYR National Occurrence Measures Based on UCMR 2 Screening Survey Data 

thru July 2011 - Summary of Samples

Table D25c. NPYR National Occurrence Measures Based on UCMR 2 Screening Survey Data 

thru July 2011 - Summary of System and Population Served Data - All Detections

Table D25d. NPYR National Occurrence Measures Based on UCMR 2 Screening Survey Data 

thru July 2011 - Summary of System and Population Served Data - Detections > 1⁄2 

HRL

Table D25e. NPYR National Occurrence Measures Based on UCMR 2 Screening Survey Data 

thru July 2011 - Summary of System and Population Served Data - Detections > 

HRL
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 1 of 74

Minimum Median 90th Percentile 99th 

Percentile Maximum

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Small Systems N/A N/A N/A N/A N/A

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Large Systems N/A N/A N/A N/A N/A

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Very Large Systems N/A N/A N/A N/A N/A

All Water Systems N/A N/A N/A N/A N/A

Table D1b. BDE-47 National Occurrence Measures Based on UCMR 2 Assessment Monitoring Data thru July 2011 - Summary of Samples

Number Percent

Ground Water 2,328 0 0.00%

Surface Water 920 0 0.00%

All Small Systems 3,248 0 0.00%

Ground Water 11,680 0 0.00%

Surface Water 10,301 0 0.00%

All Large Systems 21,981 0 0.000%

Ground Water 2,013 0 0.00%

Surface Water 4,770 0 0.00%

All Very Large Systems 6,783 0 0.00%

All Water Systems 32,012 0 0.000%

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems

Large Systems (serving 10,001 - 100,000 people) -- CENSUS

Table D1a. BDE-47 Occurrence Data from UCMR 2 Assessment Monitoring thru July 2011 - Summary of Detected Concentrations

Source Water Type

Concentration Value of Detections (μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people) -- CENSUS

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems

Small Systems (serving ≤ 10,000 people)

Source Water Type Total # of 

Samples

Samples with Detections
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 2 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%) All Water Systems 4,138 229,200,252 65,022 273,145,549

All Very Large Systems 398 141,981,684 398 141,981,684

All Systems

Ground Water 63 17,269,919 63 17,269,919

Surface Water 335 124,711,765 335 124,711,765

All Large Systems 2,940 84,549,563 2,940 84,549,563

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 1,374 34,828,693 1,374 34,828,693

Surface Water 1,566 49,720,870 1,566 49,720,870

All Small Systems 800 2,669,004 61,684 46,614,302

Large Systems (serving 10,001 - 100,000 people) -- CENSUS

57,818 37,685,557

Surface Water 182 878,262 3,866 8,928,745

Table D1c. BDE-47 National Occurrence Measures Based on UCMR 2 Assessment Monitoring Data thru July 2011 – Summary of System and 

Population Served Data -- All Detections 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections in the UCMR 2 

Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections

1 National estimates for the small systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages and national 

system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the large and very large systems are 

based directly on the UCMR 2 results, since this was a census, i.e., all large and very large systems were required to conduct UCMR 2 Assessment Monitoring. Due to 

rounding, some calculations may appear to be slightly off.

Small Systems (serving ≤ 10,000 people)

Ground Water 618 1,790,743
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 3 of 74

Minimum Median 90th Percentile 99th 

Percentile Maximum

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Small Systems N/A N/A N/A N/A N/A

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Large Systems N/A N/A N/A N/A N/A

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Very Large Systems N/A N/A N/A N/A N/A

All Water Systems N/A N/A N/A N/A N/A

Table D2b. BDE-99 National Occurrence Measures Based on UCMR 2 Assessment Monitoring Data thru July 2011 - Summary of Samples

Number Percent

Ground Water 2,328 0 0.00%

Surface Water 920 0 0.00%

All Small Systems 3,248 0 0.00%

Ground Water 11,680 0 0.00%

Surface Water 10,301 0 0.00%

All Large Systems 21,981 0 0.000%

Ground Water 2,013 0 0.00%

Surface Water 4,770 0 0.00%

All Very Large Systems 6,783 0 0.00%

All Water Systems 32,012 0 0.000%

Total # of 

Samples

Samples with Detections

Table D2a. BDE-99 Occurrence Data from UCMR 2 Assessment Monitoring thru July 2011 - Summary of Detected Concentrations

Source Water Type

Concentration Value of Detections (μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people) -- CENSUS

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems

Source Water Type

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people) -- CENSUS

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 4 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

All Systems

All Water Systems 4,138 229,200,252 65,022 273,145,549

Surface Water 335 124,711,765 335 124,711,765

All Very Large Systems 398 141,981,684 398 141,981,684

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919 63 17,269,919

Surface Water 1,566 49,720,870 1,566 49,720,870

All Large Systems 2,940 84,549,563 2,940 84,549,563

Large Systems (serving 10,001 - 100,000 people) -- CENSUS

Ground Water 1,374 34,828,693 1,374 34,828,693

Surface Water 182 878,262 3,866 8,928,745

All Small Systems 800 2,669,004 61,684 46,614,302

37,685,557

Table D2c. BDE-99 National Occurrence Measures Based on UCMR 2 Assessment Monitoring Data thru July 2011 – Summary of System and 

Population Served Data -- All Detections 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections in the UCMR 2 

Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections

1 National estimates for the small systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages and national 

system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the large and very large systems are 

based directly on the UCMR 2 results, since this was a census, i.e., all large and very large systems were required to conduct UCMR 2 Assessment Monitoring. Due to 

rounding, some calculations may appear to be slightly off.

Small Systems (serving ≤ 10,000 people)

Ground Water 618 1,790,743 57,818
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 5 of 74

Minimum Median 90th Percentile 99th 

Percentile Maximum

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Small Systems N/A N/A N/A N/A N/A

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Large Systems N/A N/A N/A N/A N/A

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Very Large Systems N/A N/A N/A N/A N/A

All Water Systems N/A N/A N/A N/A N/A

Table D3b. BDE-100 National Occurrence Measures Based on UCMR 2 Assessment Monitoring Data thru July 2011 - Summary of Samples

Number Percent

Ground Water 2,328 0 0.00%

Surface Water 920 0 0.00%

All Small Systems 3,248 0 0.00%

Ground Water 11,680 0 0.00%

Surface Water 10,301 0 0.00%

All Large Systems 21,981 0 0.000%

Ground Water 2,013 0 0.00%

Surface Water 4,770 0 0.00%

All Very Large Systems 6,783 0 0.00%

All Water Systems 32,012 0 0.000%

Large Systems (serving 10,001 - 100,000 people) -- CENSUS

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems

All Systems

Very Large Systems (serving > 100,000 people) -- CENSUS

Large Systems (serving 10,001 - 100,000 people) -- CENSUS

Small Systems (serving ≤ 10,000 people)

Table D3a. BDE-100 Occurrence Data from UCMR 2 Assessment Monitoring thru July 2011 - Summary of Detected Concentrations

Source Water Type Total # of 

Samples

Samples with Detections

Source Water Type

Concentration Value of Detections (μg/L)

Small Systems (serving ≤ 10,000 people)
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 6 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%) All Water Systems 4,138 229,200,252 65,022 273,145,549

All Very Large Systems 398 141,981,684 398 141,981,684

All Systems

Ground Water 63 17,269,919 63 17,269,919

Surface Water 335 124,711,765 335 124,711,765

All Large Systems 2,940 84,549,563 2,940 84,549,563

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 1,374 34,828,693 1,374 34,828,693

Surface Water 1,566 49,720,870 1,566 49,720,870

All Small Systems 800 2,669,004 61,684 46,614,302

Large Systems (serving 10,001 - 100,000 people) -- CENSUS

618 1,790,743 57,818 37,685,557

Surface Water 182 878,262 3,866 8,928,745

Table D3c. BDE-100 National Occurrence Measures Based on UCMR 2 Assessment Monitoring Data thru July 2011 – Summary of System and 

Population Served Data -- All Detections 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections in the UCMR 2 

Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections

1 National estimates for the small systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages and national 

system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the large and very large systems are 

based directly on the UCMR 2 results, since this was a census, i.e., all large and very large systems were required to conduct UCMR 2 Assessment Monitoring. Due to 

rounding, some calculations may appear to be slightly off.

Small Systems (serving ≤ 10,000 people)

Ground Water
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 7 of 74

Minimum Median 90th Percentile 99th 

Percentile Maximum

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Small Systems N/A N/A N/A N/A N/A

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Large Systems N/A N/A N/A N/A N/A

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Very Large Systems N/A N/A N/A N/A N/A

All Water Systems N/A N/A N/A N/A N/A

Table D4b. BDE-153 National Occurrence Measures Based on UCMR 2 Assessment Monitoring Data thru July 2011 - Summary of Samples

Number Percent

Ground Water 2,328 0 0.00%

Surface Water 920 0 0.00%

All Small Systems 3,248 0 0.00%

Ground Water 11,679 0 0.00%

Surface Water 10,294 0 0.00%

All Large Systems 21,973 0 0.000%

Ground Water 2,013 0 0.00%

Surface Water 4,768 0 0.00%

All Very Large Systems 6,781 0 0.00%

All Water Systems 32,002 0 0.000%

Total # of 

Samples

Samples with Detections

Large Systems (serving 10,001 - 100,000 people) -- CENSUS

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems

All Systems

Small Systems (serving ≤ 10,000 people)

Table D4a. BDE-153 Occurrence Data from UCMR 2 Assessment Monitoring thru July 2011 - Summary of Detected Concentrations

Source Water Type

Concentration Value of Detections (μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people) -- CENSUS

Very Large Systems (serving > 100,000 people) -- CENSUS

Source Water Type
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 8 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%) All Water Systems 4,138 229,200,252 65,022 273,145,549

All Very Large Systems 398 141,981,684 398 141,981,684

All Systems

Ground Water 63 17,269,919 63 17,269,919

Surface Water 335 124,711,765 335 124,711,765

All Large Systems 2,940 84,549,563 2,940 84,549,563

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 1,374 34,828,693 1,374 34,828,693

Surface Water 1,566 49,720,870 1,566 49,720,870

All Small Systems 800 2,669,004 61,684 46,614,302

Large Systems (serving 10,001 - 100,000 people) -- CENSUS

Ground Water 618 1,790,743 57,818 37,685,557

Surface Water 182 878,262 3,866 8,928,745

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections in the UCMR 2 

Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections

Small Systems (serving ≤ 10,000 people)

Table D4c. BDE-153 National Occurrence Measures Based on UCMR 2 Assessment Monitoring Data thru July 2011 – Summary of System 

and Population Served Data -- All Detections 

1 National estimates for the small systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages and 

national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the large and very large 

systems are based directly on the UCMR 2 results, since this was a census, i.e., all large and very large systems were required to conduct UCMR 2 Assessment 

Monitoring. Due to rounding, some calculations may appear to be slightly off.
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 9 of 74

Table D5a. Dimethoate Occurrence Data from UCMR 2 Assessment Monitoring thru July 2011 - Summary of Detected Concentrations

Minimum Median 90th Percentile 99th 

Percentile Maximum

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Small Systems N/A N/A N/A N/A N/A

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Large Systems N/A N/A N/A N/A N/A

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Very Large Systems N/A N/A N/A N/A N/A

All Water Systems N/A N/A N/A N/A N/A

Table D5b. Dimethoate National Occurrence Measures Based on UCMR 2 Assessment Monitoring Data thru July 2011 - Summary of Samples

Number Percent Number Percent Number Percent

Ground Water 2,328 0 0.00% 0 0.00% 0 0.00%

Surface Water 920 0 0.00% 0 0.00% 0 0.00%

All Small Systems 3,248 0 0.00% 0 0.00% 0 0.00%

Ground Water 11,680 0 0.00% 0 0.00% 0 0.00%

Surface Water 10,302 0 0.00% 0 0.00% 0 0.00%

All Large Systems 21,982 0 0.00% 0 0.00% 0 0.00%

Ground Water 2,013 0 0.00% 0 0.00% 0 0.00%

Surface Water 4,770 0 0.00% 0 0.00% 0 0.00%

All Very Large Systems 6,783 0 0.00% 0 0.00% 0 0.00%

All Water Systems 32,013 0 0.00% 0 0.00% 0 0.00%

Source Water Type

Concentration Value of Detections (μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people) -- CENSUS

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems

Source Water Type Total # of 

Samples

Samples with Detections Samples with Detections 

> 1⁄2 HRL (7.7 μg/L)

Samples with Detections 

> HRL (15.4 μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people) -- CENSUS

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 10 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

All Systems

All Water Systems 4,138 229,200,252 65,022 273,145,549

Surface Water 335 124,711,765 335 124,711,765

All Very Large Systems 398 141,981,684 398 141,981,684

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919 63 17,269,919

Surface Water 1,566 49,720,870 1,566 49,720,870

All Large Systems 2,940 84,549,563 2,940 84,549,563

Large Systems (serving 10,001 - 100,000 people) -- CENSUS

Ground Water 1,374 34,828,693 1,374 34,828,693

3,866 8,928,745

All Small Systems 800 2,669,004 61,684 46,614,302

Table D5c. Dimethoate National Occurrence Measures Based on UCMR 2 Assessment Monitoring Data thru July 2011 – Summary of System 

and Population Served Data -- All Detections 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections in the UCMR 2 

Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections

1 National estimates for the small systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages and 

national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the large and very large 

systems are based directly on the UCMR 2 results, since this was a census, i.e., all large and very large systems were required to conduct UCMR 2 Assessment 

Monitoring. Due to rounding, some calculations may appear to be slightly off.

Small Systems (serving ≤ 10,000 people)

Ground Water 618 1,790,743 57,818 37,685,557

Surface Water 182 878,262
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 11 of 74

Minimum Median 90th Percentile 99th 

Percentile Maximum

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Small Systems N/A N/A N/A N/A N/A

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Large Systems N/A N/A N/A N/A N/A

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Very Large Systems N/A N/A N/A N/A N/A

All Water Systems N/A N/A N/A N/A N/A

Table D6b. 1,3-Dinitrobenzene National Occurrence Measures Based on UCMR 2 Assessment Monitoring Data thru July 2011 - Summary of S

Number Percent Number Percent Number Percent

Ground Water 2,332 0 0.00% 0 0.00% 0 0.00%

Surface Water 919 0 0.00% 0 0.00% 0 0.00%

All Small Systems 3,251 0 0.00% 0 0.00% 0 0.00%

Ground Water 11,682 0 0.00% 0 0.00% 0 0.00%

Surface Water 10,298 0 0.00% 0 0.00% 0 0.00%

All Large Systems 21,980 0 0.00% 0 0.00% 0 0.00%

Ground Water 2,011 0 0.00% 0 0.00% 0 0.00%

Surface Water 4,775 0 0.00% 0 0.00% 0 0.00%

All Very Large Systems 6,786 0 0.00% 0 0.00% 0 0.00%

All Water Systems 32,017 0 0.00% 0 0.00% 0 0.00%

Samples with Detections 

> 1⁄2 HRL (0.35 μg/L)

Samples with Detections 

> HRL (0.7 μg/L)

Small Systems (serving ≤ 10,000 people)

Source Water Type

Concentration Value of Detections (μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people) -- CENSUS

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems

Large Systems (serving 10,001 - 100,000 people) -- CENSUS

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems

Table D6a. 1,3-Dinitrobenzene Occurrence Data from UCMR 2 Assessment Monitoring thru July 2011 - Summary of Detected 

Concentrations

Source Water Type Total # of 

Samples

Samples with Detections
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 12 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

All Systems

All Water Systems 4,137 229,188,252 65,021 273,133,549

Surface Water 335 124,711,765 335 124,711,765

All Very Large Systems 398 141,981,684 398 141,981,684

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919 63 17,269,919

Surface Water 1,566 49,720,870 1,566 49,720,870

All Large Systems 2,939 84,537,563 2,939 84,537,563

Large Systems (serving 10,001 - 100,000 people) -- CENSUS

Ground Water 1,373 34,816,693 1,373 34,816,693

Surface Water 182 878,262 3,866 8,928,745

All Small Systems 800 2,669,004 61,684 46,614,302

37,685,557

Table D6c. 1,3-Dinitrobenzene National Occurrence Measures Based on UCMR 2 Assessment Monitoring Data thru July 2011 – Summary of 

System and Population Served Data -- All Detections 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections in the UCMR 2 

Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections

1 National estimates for the small systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages and 

national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the large and very large 

systems are based directly on the UCMR 2 results, since this was a census, i.e., all large and very large systems were required to conduct UCMR 2 Assessment 

Monitoring. Due to rounding, some calculations may appear to be slightly off.

Small Systems (serving ≤ 10,000 people)

Ground Water 618 1,790,743 57,818
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 13 of 74

Table D7a. HBB Occurrence Data from UCMR 2 Assessment Monitoring thru July 2011 - Summary of Detected Concentrations

Minimum Median 90th Percentile 99th 

Percentile Maximum

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Small Systems N/A N/A N/A N/A N/A

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Large Systems N/A N/A N/A N/A N/A

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Very Large Systems N/A N/A N/A N/A N/A

All Water Systems N/A N/A N/A N/A N/A

Table D7b. HBB National Occurrence Measures Based on UCMR 2 Assessment Monitoring Data thru July 2011 - Summary of Samples

Number Percent

Ground Water 2,328 0 0.00%

Surface Water 920 0 0.00%

All Small Systems 3,248 0 0.00%

Ground Water 11,679 0 0.00%

Surface Water 10,298 0 0.00%

All Large Systems 21,977 0 0.000%

Ground Water 2,013 0 0.00%

Surface Water 4,768 0 0.00%

All Very Large Systems 6,781 0 0.00%

All Water Systems 32,006 0 0.000%

Source Water Type Total # of 

Samples

Samples with Detections

Source Water Type

Concentration Value of Detections (μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people) -- CENSUS

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems

All Systems

Very Large Systems (serving > 100,000 people) -- CENSUS

Large Systems (serving 10,001 - 100,000 people) -- CENSUS

Small Systems (serving ≤ 10,000 people)
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 14 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

All Systems

All Water Systems 4,138 229,200,252 65,022 273,145,549

Surface Water 335 124,711,765 335 124,711,765

All Very Large Systems 398 141,981,684 398 141,981,684

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919 63 17,269,919

Surface Water 1,566 49,720,870 1,566 49,720,870

All Large Systems 2,940 84,549,563 2,940 84,549,563

Large Systems (serving 10,001 - 100,000 people) -- CENSUS

Ground Water 1,374 34,828,693 1,374 34,828,693

Surface Water 182 878,262 3,866 8,928,745

All Small Systems 800 2,669,004 61,684 46,614,302

37,685,557

Table D7c. HBB National Occurrence Measures Based on UCMR 2 Assessment Monitoring Data thru July 2011 – Summary of System and 

Population Served Data -- All Detections 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections in the UCMR 2 

Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections

1 National estimates for the small systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages and 

national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the large and very large 

systems are based directly on the UCMR 2 results, since this was a census, i.e., all large and very large systems were required to conduct UCMR 2 Assessment 

Monitoring. Due to rounding, some calculations may appear to be slightly off.

Small Systems (serving ≤ 10,000 people)

Ground Water 618 1,790,743 57,818
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 15 of 74

Table D8a. RDX Occurrence Data from UCMR 2 Assessment Monitoring thru July 2011 - Summary of Detected Concentrations

Minimum Median 90th Percentile 99th 

Percentile Maximum

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Small Systems N/A N/A N/A N/A N/A

Ground Water N/A N/A N/A N/A N/A

Surface Water 1 1.065 1.1 1.1 1.1

All Large Systems 1 1.065 1.1 1.1 1.1

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Very Large Systems N/A N/A N/A N/A N/A

All Water Systems 1 1.065 1.1 1.1 1.1

Table D8b. RDX National Occurrence Measures Based on UCMR 2 Assessment Monitoring Data thru July 2011 - Summary of Samples

Number Percent Number Percent Number Percent

Ground Water 2,332 0 0.00% 0 0.00% 0 0.00%

Surface Water 919 0 0.00% 0 0.00% 0 0.00%

All Small Systems 3,251 0 0.00% 0 0.00% 0 0.00%

Ground Water 11,681 0 0.00% 0 0.00% 0 0.00%

Surface Water 10,298 4 0.04% 0 0.00% 0 0.00%

All Large Systems 21,979 4 0.02% 0 0.00% 0 0.00%

Ground Water 2,011 0 0.00% 0 0.00% 0 0.00%

Surface Water 4,774 0 0.00% 0 0.00% 0 0.00%

All Very Large Systems 6,785 0 0.00% 0 0.00% 0 0.00%

All Water Systems 32,015 4 0.01% 0 0.00% 0 0.00%

Source Water Type

Concentration Value of Detections (μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people) -- CENSUS

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems

Source Water Type Total # of 

Samples

Samples with Detections Samples with Detections 

> 1⁄2 HRL (10.5 μg/L)

Samples with Detections 

> HRL (21 μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people) -- CENSUS

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 16 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

3 96,033 3 96,033

(0.19%) (0.19%) (0.19%) (0.19%)

3 96,033 3 96,033

(0.1%) (0.11%) (0.1%) (0.11%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

3 96,033 3 96,033

(0.07%) (0.04%) (0.005%) (0.04%)

Table D8c. RDX National Occurrence Measures Based on UCMR 2 Assessment Monitoring Data thru July 2011 – Summary of System and 

Population Served Data -- All Detections 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections in the UCMR 2 

Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections

Small Systems (serving ≤ 10,000 people)

Ground Water 618 1,790,743 57,818 37,685,557

Surface Water 182 878,262 3,866 8,928,745

All Small Systems 800 2,669,004 61,684 46,614,302

Large Systems (serving 10,001 - 100,000 people) -- CENSUS

Ground Water 1,373 34,816,693 1,373 34,816,693

Surface Water 1,566 49,720,870 1,566 49,720,870

All Large Systems 2,939 84,537,563 2,939 84,537,563

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919 63 17,269,919

Surface Water 335 124,711,765 335 124,711,765

All Very Large Systems 398 141,981,684 398 141,981,684

All Systems

All Water Systems 4,137 229,188,252 65,021 273,133,549

1 National estimates for the small systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages and 

national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the large and very large 

systems are based directly on the UCMR 2 results, since this was a census, i.e., all large and very large systems were required to conduct UCMR 2 Assessment 

Monitoring. Due to rounding, some calculations may appear to be slightly off.
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 17 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

Table D8d. RDX National Occurrence Measures Based on UCMR 2 Assessment Monitoring Data thru July 2011 – Summary of System and 

Population Served Data -- Detections > 1/2 HRL 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections > 1/2 HRL (10.5 

μg/L) in the UCMR 2 Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections > 1/2 HRL (10.5 

μg/L)

Small Systems (serving ≤ 10,000 people)

Ground Water 618 1,790,743 57,818 37,685,557

Surface Water 182 878,262 3,866 8,928,745

All Small Systems 800 2,669,004 61,684 46,614,302

Large Systems (serving 10,001 - 100,000 people) -- CENSUS

Ground Water 1,373 34,816,693 1,373 34,816,693

Surface Water 1,566 49,720,870 1,566 49,720,870

All Large Systems 2,939 84,537,563 2,939 84,537,563

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919 63 17,269,919

Surface Water 335 124,711,765 335 124,711,765

All Very Large Systems 398 141,981,684 398 141,981,684

All Systems

All Water Systems 4,137 229,188,252 65,021 273,133,549

1 National estimates for the small systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages and 

national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the large and very large 

systems are based directly on the UCMR 2 results, since this was a census, i.e., all large and very large systems were required to conduct UCMR 2 Assessment 

Monitoring. Due to rounding, some calculations may appear to be slightly off.
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 18 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

Table D8e. RDX National Occurrence Measures Based on UCMR 2 Assessment Monitoring Data thru July 2011 – Summary of System and 

Population Served Data -- Detections > HRL 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections > HRL (21 μg/L) in 

the UCMR 2 Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections > HRL (21 μg/L)

Small Systems (serving ≤ 10,000 people)

Ground Water 618 1,790,743 57,818 37,685,557

Surface Water 182 878,262 3,866 8,928,745

All Small Systems 800 2,669,004 61,684 46,614,302

Large Systems (serving 10,001 - 100,000 people) -- CENSUS

Ground Water 1,373 34,816,693 1,373 34,816,693

Surface Water 1,566 49,720,870 1,566 49,720,870

All Large Systems 2,939 84,537,563 2,939 84,537,563

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919 63 17,269,919

335 124,711,765 335 124,711,765

All Very Large Systems 398 141,981,684 398 141,981,684

1 National estimates for the small systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages and 

national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the large and very large 

systems are based directly on the UCMR 2 results, since this was a census, i.e., all large and very large systems were required to conduct UCMR 2 Assessment 

Monitoring. Due to rounding, some calculations may appear to be slightly off.

All Systems

All Water Systems 4,137 229,188,252 65,021 273,133,549

Surface Water
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 19 of 74

Minimum Median 90th Percentile 99th 

Percentile Maximum

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Small Systems N/A N/A N/A N/A N/A

Ground Water 0.42 0.42 0.42 0.42 0.42

Surface Water N/A N/A N/A N/A N/A

All Large Systems 0.42 0.42 0.42 0.42 0.42

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Very Large Systems N/A N/A N/A N/A N/A

All Water Systems 0.42 0.42 0.42 0.42 0.42

Table D9b. Terbufos Sulfone National Occurrence Measures Based on UCMR 2 Assessment Monitoring Data thru July 2011 - Summary of Sa

Number Percent Number Percent Number Percent

Ground Water 2,328 0 0.00% 0 0.00% 0 0.00%

Surface Water 920 0 0.00% 0 0.00% 0 0.00%

All Small Systems 3,248 0 0.00% 0 0.00% 0 0.00%

Ground Water 11,680 1 0.01% 1 0.01% 1 0.01%

Surface Water 10,301 0 0.00% 0 0.00% 0 0.00%

All Large Systems 21,981 1 0.005% 1 0.005% 1 0.005%

Ground Water 2,013 0 0.00% 0 0.00% 0 0.00%

Surface Water 4,770 0 0.00% 0 0.00% 0 0.00%

All Very Large Systems 6,783 0 0.00% 0 0.00% 0 0.00%

All Water Systems 32,012 1 0.003% 1 0.003% 1 0.003%

Source Water Type

Concentration Value of Detections (μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people) -- CENSUS

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems

Source Water Type Total # of 

Samples

Samples with Detections Samples with Detections 

> 1⁄2 HRL (0.175 μg/L)

Samples with Detections 

> HRL (0.35 μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people) -- CENSUS

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems

Table D9a. Terbufos Sulfone Occurrence Data from UCMR 2 Assessment Monitoring thru July 2011 - Summary of Detected Concentrations
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 20 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

1 44,600 1 44,600

(0.07%) (0.13%) (0.07%) (0.13%)

0 0 0 0

(0%) (0%) (0%) (0%)

1 44,600 1 44,600

(0.03%) (0.05%) (0.03%) (0.05%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

1 44,600 1 44,600

(0.02%) (0.02%) (0.002%) (0.02%)

Table D9c. Terbufos Sulfone National Occurrence Measures Based on UCMR 2 Assessment Monitoring Data thru July 2011 – Summary of 

System and Population Served Data -- All Detections 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections in the UCMR 2 

Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections

Small Systems (serving ≤ 10,000 people)

Ground Water 618 1,790,743 57,818 37,685,557

Surface Water 182 878,262 3,866 8,928,745

All Small Systems 800 2,669,004 61,684 46,614,302

Large Systems (serving 10,001 - 100,000 people) -- CENSUS

Ground Water 1,374 34,828,693 1,374 34,828,693

Surface Water 1,566 49,720,870 1,566 49,720,870

All Large Systems 2,940 84,549,563 2,940 84,549,563

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919 63 17,269,919

Surface Water 335 124,711,765 335 124,711,765

All Very Large Systems 398 141,981,684 398 141,981,684

All Systems

All Water Systems 4,138 229,200,252 65,022 273,145,549

1 National estimates for the small systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages and 

national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the large and very large 

systems are based directly on the UCMR 2 results, since this was a census, i.e., all large and very large systems were required to conduct UCMR 2 Assessment 

Monitoring. Due to rounding, some calculations may appear to be slightly off.
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 21 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

1 44,600 1 44,600

(0.07%) (0.13%) (0.07%) (0.13%)

0 0 0 0

(0%) (0%) (0%) (0%)

1 44,600 1 44,600

(0.03%) (0.05%) (0.03%) (0.05%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

1 44,600 1 44,600

(0.02%) (0.02%) (0.002%) (0.02%)

Table D9d. Terbufos Sulfone National Occurrence Measures Based on UCMR 2 Assessment Monitoring Data thru July 2011 – Summary of 

System and Population Served Data -- Detections > 1/2 HRL 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections > 1/2 HRL (0.175 

μg/L) in the UCMR 2 Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections > 1/2 HRL (0.175 

μg/L)

Small Systems (serving ≤ 10,000 people)

Ground Water 618 1,790,743 57,818 37,685,557

Surface Water 182 878,262 3,866 8,928,745

All Small Systems 800 2,669,004 61,684 46,614,302

Large Systems (serving 10,001 - 100,000 people) -- CENSUS

Ground Water 1,374 34,828,693 1,374 34,828,693

Surface Water 1,566 49,720,870 1,566 49,720,870

All Large Systems 2,940 84,549,563 2,940 84,549,563

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919 63 17,269,919

Surface Water 335 124,711,765 335 124,711,765

All Very Large Systems 398 141,981,684 398 141,981,684

All Systems

All Water Systems 4,138 229,200,252 65,022 273,145,549

1 National estimates for the small systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages and 

national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the large and very large 

systems are based directly on the UCMR 2 results, since this was a census, i.e., all large and very large systems were required to conduct UCMR 2 Assessment 

Monitoring. Due to rounding, some calculations may appear to be slightly off.
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 22 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

1 44,600 1 44,600

(0.07%) (0.13%) (0.07%) (0.13%)

0 0 0 0

(0%) (0%) (0%) (0%)

1 44,600 1 44,600

(0.03%) (0.05%) (0.03%) (0.05%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

1 44,600 1 44,600

(0.02%) (0.02%) (0.002%) (0.02%)

Table D9e. Terbufos Sulfone National Occurrence Measures Based on UCMR 2 Assessment Monitoring Data thru July 2011 – Summary of 

System and Population Served Data -- Detections > HRL 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections > HRL (0.35 μg/L) 

in the UCMR 2 Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections > HRL (0.35 μg/L)

Small Systems (serving ≤ 10,000 people)

Ground Water 618 1,790,743 57,818 37,685,557

Surface Water 182 878,262 3,866 8,928,745

All Small Systems 800 2,669,004 61,684 46,614,302

Large Systems (serving 10,001 - 100,000 people) -- CENSUS

Ground Water 1,374 34,828,693 1,374 34,828,693

Surface Water 1,566 49,720,870 1,566 49,720,870

All Large Systems 2,940 84,549,563 2,940 84,549,563

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919 63 17,269,919

335 124,711,765 335 124,711,765

All Very Large Systems 398 141,981,684 398 141,981,684

1 National estimates for the small systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages and 

national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the large and very large 

systems are based directly on the UCMR 2 results, since this was a census, i.e., all large and very large systems were required to conduct UCMR 2 Assessment 

Monitoring. Due to rounding, some calculations may appear to be slightly off.

All Systems

All Water Systems 4,138 229,200,252 65,022 273,145,549

Surface Water
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 23 of 74

Table D10a. TNT Occurrence Data from UCMR 2 Assessment Monitoring thru July 2011 - Summary of Detected Concentrations

Minimum Median 90th Percentile 99th 

Percentile Maximum

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Small Systems N/A N/A N/A N/A N/A

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Large Systems N/A N/A N/A N/A N/A

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Very Large Systems N/A N/A N/A N/A N/A

All Water Systems N/A N/A N/A N/A N/A

Table D10b. TNT National Occurrence Measures Based on UCMR 2 Assessment Monitoring Data thru July 2011 - Summary of Samples

Number Percent

Ground Water 2,332 0 0.00%

Surface Water 919 0 0.00%

All Small Systems 3,251 0 0.00%

Ground Water 11,681 0 0.00%

Surface Water 10,297 0 0.00%

All Large Systems 21,978 0 0.000%

Ground Water 2,011 0 0.00%

Surface Water 4,775 0 0.00%

All Very Large Systems 6,786 0 0.00%

All Water Systems 32,015 0 0.000%

Source Water Type Total # of 

Samples

Samples with Detections

Source Water Type

Concentration Value of Detections (μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people) -- CENSUS

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people) -- CENSUS

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 24 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

All Systems

All Water Systems 4,137 229,188,252 65,021 273,133,549

Surface Water 335 124,711,765 335 124,711,765

All Very Large Systems 398 141,981,684 398 141,981,684

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919 63 17,269,919

Surface Water 1,566 49,720,870 1,566 49,720,870

All Large Systems 2,939 84,537,563 2,939 84,537,563

Large Systems (serving 10,001 - 100,000 people) -- CENSUS

Ground Water 1,373 34,816,693 1,373 34,816,693

Surface Water 182 878,262 3,866 8,928,745

All Small Systems 800 2,669,004 61,684 46,614,302

37,685,557

Table D10c. TNT National Occurrence Measures Based on UCMR 2 Assessment Monitoring Data thru July 2011 – Summary of System and 

Population Served Data -- All Detections 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections in the UCMR 2 

Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections

1 National estimates for the small systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages and 

national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the large and very large 

systems are based directly on the UCMR 2 results, since this was a census, i.e., all large and very large systems were required to conduct UCMR 2 Assessment 

Monitoring. Due to rounding, some calculations may appear to be slightly off.

Small Systems (serving ≤ 10,000 people)

Ground Water 618 1,790,743 57,818
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 25 of 74

Table D11a. Acetochlor Occurrence Data from UCMR 2 Screening Survey thru July 2011 - Summary of Detected Concentrations

Minimum Median 90th Percentile 99th 

Percentile Maximum

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Small Systems N/A N/A N/A N/A N/A

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Large Systems N/A N/A N/A N/A N/A

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Very Large Systems N/A N/A N/A N/A N/A

All Water Systems N/A N/A N/A N/A N/A

Table D11b. Acetochlor National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 - Summary of Samples

Number Percent Number Percent Number Percent

Ground Water 788 0 0.00% 0 0.00% 0 0.00%

Surface Water 1,040 0 0.00% 0 0.00% 0 0.00%

All Small Systems 1,828 0 0.00% 0 0.00% 0 0.00%

Ground Water 1,382 0 0.00% 0 0.00% 0 0.00%

Surface Water 1,178 0 0.00% 0 0.00% 0 0.00%

All Large Systems 2,560 0 0.00% 0 0.00% 0 0.00%

Ground Water 2,009 0 0.00% 0 0.00% 0 0.00%

Surface Water 4,741 0 0.00% 0 0.00% 0 0.00%

All Very Large Systems 6,750 0 0.00% 0 0.00% 0 0.00%

All Water Systems 11,138 0 0.00% 0 0.00% 0 0.00%

Source Water Type

Concentration Value of Detections (μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people)

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems

Source Water Type Total # of 

Samples

Samples with Detections Samples with Detections 

> 1⁄2 HRL (0.5 μg/L)

Samples with Detections 

> HRL (1 μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people)

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 26 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

All Systems

All Water Systems 1,198 157,219,620 64,954 272,002,430

Surface Water 335 124,711,765 335 124,711,765

All Very Large Systems 398 141,981,684 398 141,981,684

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919 63 17,269,919

Surface Water 169 7,444,830 1,366 44,536,172

All Large Systems 320 14,029,015 2,872 83,406,444

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184 1,506 38,870,272

3,866 8,928,745

All Small Systems 480 1,208,921 61,684 46,614,302

Table D11c. Acetochlor National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 – Summary of System and 

Population Served Data -- All Detections 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections in the UCMR 2 

Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections

1 National estimates for the small and large systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages 

and national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems 

are based directly on the UCMR 2 results, since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey Monitoring. Due 

to rounding, some calculations may appear to be slightly off.

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364 57,818 37,685,557

Surface Water 240 660,557
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 27 of 74

Table D12a. Acetochlor ESA Occurrence Data from UCMR 2 Screening Survey thru July 2011 - Summary of Detected Concentrations

Minimum Median 90th Percentile 99th 

Percentile Maximum

Ground Water N/A N/A N/A N/A N/A

Surface Water 1.10526 1.10526 1.10526 1.10526 1.10526

All Small Systems 1.10526 1.10526 1.10526 1.10526 1.10526

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Large Systems N/A N/A N/A N/A N/A

Ground Water N/A N/A N/A N/A N/A

Surface Water 1.2 1.2 1.2 1.2 1.2

All Very Large Systems 1.2 1.2 1.2 1.2 1.2

All Water Systems 1.10526 1.15263 1.190526 1.1990526 1.2

Table D12b. Acetochlor ESA National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 - Summary of Samples

Number Percent Number Percent Number Percent

Ground Water 786 0 0.00% 0 0.00% 0 0.00%

Surface Water 1,035 1 0.10% 1 0.10% 1 0.10%

All Small Systems 1,821 1 0.05% 1 0.05% 1 0.05%

Ground Water 1,377 0 0.00% 0 0.00% 0 0.00%

Surface Water 1,166 0 0.00% 0 0.00% 0 0.00%

All Large Systems 2,543 0 0.00% 0 0.00% 0 0.00%

Ground Water 1,997 0 0.00% 0 0.00% 0 0.00%

Surface Water 4,739 1 0.02% 1 0.02% 1 0.02%

All Very Large Systems 6,736 1 0.01% 1 0.01% 1 0.01%

All Water Systems 11,100 2 0.02% 2 0.02% 2 0.02%

Source Water Type

Concentration Value of Detections (μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people)

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems

Source Water Type Total # of 

Samples

Samples with Detections Samples with Detections 

> 1⁄2 HRL (0.5 μg/L)

Samples with Detections 

> HRL (1 μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people)

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 28 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

1 3,455 16 46,701

(0.42%) (0.52%) (0.42%) (0.52%)

1 3,455 16 46,701

(0.21%) (0.29%) (0.03%) (0.1%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

1 3,828,700 1 3,828,700

(0.3%) (3.07%) (0.3%) (3.07%)

1 3,828,700 1 3,828,700

(0.25%) (2.7%) (0.25%) (2.7%)

2 3,832,155 17 3,875,401

(0.17%) (2.44%) (0.03%) (1.42%)

All Systems

All Water Systems 1,198 157,219,620 64,954 272,002,430

Surface Water 335 124,711,765 335 124,711,765

All Very Large Systems 398 141,981,684 398 141,981,684

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919 63 17,269,919

169 7,444,830 1,366 44,536,172

All Large Systems 320 14,029,015 2,872 83,406,444

Table D12c. Acetochlor ESA National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 – Summary of System 

and Population Served Data -- All Detections 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections in the UCMR 2 

Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364 57,818 37,685,557

Surface Water 240 660,557 3,866 8,928,745

All Small Systems 480 1,208,921 61,684 46,614,302

1 National estimates for the small and large systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages 

and national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems 

are based directly on the UCMR 2 results, since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey Monitoring. Due 

to rounding, some calculations may appear to be slightly off.

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184 1,506 38,870,272

Surface Water
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 29 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

1 3,455 16 46,701

(0.42%) (0.52%) (0.42%) (0.52%)

1 3,455 16 46,701

(0.21%) (0.29%) (0.03%) (0.1%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

1 3,828,700 1 3,828,700

(0.3%) (3.07%) (0.3%) (3.07%)

1 3,828,700 1 3,828,700

(0.25%) (2.7%) (0.25%) (2.7%)

2 3,832,155 17 3,875,401

(0.17%) (2.44%) (0.03%) (1.42%)

All Systems

All Water Systems 1,198 157,219,620 64,954 272,002,430

Surface Water 335 124,711,765 335 124,711,765

All Very Large Systems 398 141,981,684 398 141,981,684

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919 63 17,269,919

Surface Water 169 7,444,830 1,366 44,536,172

All Large Systems 320 14,029,015 2,872 83,406,444

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184 1,506 38,870,272

Surface Water 240 660,557 3,866 8,928,745

All Small Systems 480 1,208,921 61,684 46,614,302

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364 57,818 37,685,557

Table D12d. Acetochlor ESA National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 – Summary of System 

and Population Served Data -- Detections > 1/2 HRL 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections > 1/2 HRL (0.5 

μg/L) in the UCMR 2 Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections > 1/2 HRL (0.5 

μg/L)

1 National estimates for the small and large systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages 

and national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems 

are based directly on the UCMR 2 results, since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey Monitoring. Due 

to rounding, some calculations may appear to be slightly off.
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 30 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

1 3,455 16 46,701

(0.42%) (0.52%) (0.42%) (0.52%)

1 3,455 16 46,701

(0.21%) (0.29%) (0.03%) (0.1%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

1 3,828,700 1 3,828,700

(0.3%) (3.07%) (0.3%) (3.07%)

1 3,828,700 1 3,828,700

(0.25%) (2.7%) (0.25%) (2.7%)

2 3,832,155 17 3,875,401

(0.17%) (2.44%) (0.03%) (1.42%)

All Systems

All Water Systems 1,198 157,219,620 64,954 272,002,430

Surface Water 335 124,711,765 335 124,711,765

All Very Large Systems 398 141,981,684 398 141,981,684

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919 63 17,269,919

Surface Water 169 7,444,830 1,366 44,536,172

All Large Systems 320 14,029,015 2,872 83,406,444

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184 1,506 38,870,272

Surface Water 240 660,557 3,866 8,928,745

All Small Systems 480 1,208,921 61,684 46,614,302

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364 57,818 37,685,557

Table D12e. Acetochlor ESA National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 – Summary of System 

and Population Served Data -- Detections > HRL 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections > HRL (1 μg/L) in 

the UCMR 2 Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections > HRL (1 μg/L)

1 National estimates for the small and large systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages 

and national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems 

are based directly on the UCMR 2 results, since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey Monitoring. Due 

to rounding, some calculations may appear to be slightly off.
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 31 of 74

Table D13a. Acetochlor OA Occurrence Data from UCMR 2 Screening Survey thru July 2011 - Summary of Detected Concentrations

Minimum Median 90th Percentile 99th 

Percentile Maximum

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Small Systems N/A N/A N/A N/A N/A

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Large Systems N/A N/A N/A N/A N/A

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Very Large Systems N/A N/A N/A N/A N/A

All Water Systems N/A N/A N/A N/A N/A

Table D13b. Acetochlor OA National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 - Summary of Samples

Number Percent Number Percent Number Percent

Ground Water 786 0 0.00% 0 0.00% 0 0.00%

Surface Water 1,035 0 0.00% 0 0.00% 0 0.00%

All Small Systems 1,821 0 0.00% 0 0.00% 0 0.00%

Ground Water 1,377 0 0.00% 0 0.00% 0 0.00%

Surface Water 1,166 0 0.00% 0 0.00% 0 0.00%

All Large Systems 2,543 0 0.00% 0 0.00% 0 0.00%

Ground Water 1,997 0 0.00% 0 0.00% 0 0.00%

Surface Water 4,739 0 0.00% 0 0.00% 0 0.00%

All Very Large Systems 6,736 0 0.00% 0 0.00% 0 0.00%

All Water Systems 11,100 0 0.00% 0 0.00% 0 0.00%

Source Water Type

Concentration Value of Detections (μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people)

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems

Source Water Type Total # of 

Samples

Samples with Detections Samples with Detections 

> 1⁄2 HRL (0.5 μg/L)

Samples with Detections 

> HRL (1 μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people)

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 32 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

All Systems

All Water Systems 1,198 157,219,620 64,954 272,002,430

Surface Water 335 124,711,765 335 124,711,765

All Very Large Systems 398 141,981,684 398 141,981,684

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919 63 17,269,919

Surface Water 169 7,444,830 1,366 44,536,172

All Large Systems 320 14,029,015 2,872 83,406,444

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184 1,506 38,870,272

3,866 8,928,745

All Small Systems 480 1,208,921 61,684 46,614,302

Table D13c. Acetochlor OA National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 – Summary of System 

and Population Served Data -- All Detections 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections in the UCMR 2 

Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections

1 National estimates for the small and large systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages 

and national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems 

are based directly on the UCMR 2 results, since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey Monitoring. Due 

to rounding, some calculations may appear to be slightly off.

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364 57,818 37,685,557

Surface Water 240 660,557
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 33 of 74

Table D14a. Alachlor Occurrence Data from UCMR 2 Screening Survey thru July 2011 - Summary of Detected Concentrations

Minimum Median 90th Percentile 99th 

Percentile Maximum

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Small Systems N/A N/A N/A N/A N/A

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Large Systems N/A N/A N/A N/A N/A

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Very Large Systems N/A N/A N/A N/A N/A

All Water Systems N/A N/A N/A N/A N/A

Table D14b. Alachlor National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 - Summary of Samples

Number Percent

Ground Water 788 0 0.00%

Surface Water 1,040 0 0.00%

All Small Systems 1,828 0 0.00%

Ground Water 1,382 0 0.00%

Surface Water 1,178 0 0.00%

All Large Systems 2,560 0 0.000%

Ground Water 2,009 0 0.00%

Surface Water 4,741 0 0.00%

All Very Large Systems 6,750 0 0.00%

All Water Systems 11,138 0 0.000%

Source Water Type Total # of 

Samples

Samples with Detections

Source Water Type

Concentration Value of Detections (μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people)

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people)

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 34 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

All Systems

All Water Systems 1,198 157,219,620 64,954 272,002,430

Surface Water 335 124,711,765 335 124,711,765

All Very Large Systems 398 141,981,684 398 141,981,684

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919 63 17,269,919

Surface Water 169 7,444,830 1,366 44,536,172

All Large Systems 320 14,029,015 2,872 83,406,444

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184 1,506 38,870,272

Surface Water 240 660,557 3,866 8,928,745

All Small Systems 480 1,208,921 61,684 46,614,302

37,685,557

Table D14c. Alachlor National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 – Summary of System and 

Population Served Data -- All Detections 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections in the UCMR 2 

Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections

1 National estimates for the small and large systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages 

and national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems 

are based directly on the UCMR 2 results, since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey Monitoring. Due 

to rounding, some calculations may appear to be slightly off.

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364 57,818
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 35 of 74

Table D15a. Alachlor ESA Occurrence Data from UCMR 2 Screening Survey thru July 2011 - Summary of Detected Concentrations

Minimum Median 90th Percentile 99th 

Percentile Maximum

Ground Water N/A N/A N/A N/A N/A

Surface Water 1.00 1.20 1.20 1.20 1.20

All Small Systems 1.00 1.20 1.20 1.20 1.20

Ground Water 1.06 1.06 1.06 1.06 1.06

Surface Water N/A N/A N/A N/A N/A

All Large Systems 1.06 1.06 1.06 1.06 1.06

Ground Water N/A N/A N/A N/A N/A

Surface Water 1.30 1.30 1.30 1.30 1.30

All Very Large Systems 1.30 1.30 1.30 1.30 1.30

All Water Systems 1.00 1.20 1.26 1.30 1.30

Table D15b. Alachlor ESA National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 - Summary of Samples

Number Percent Number Percent Number Percent

Ground Water 786 0 0.00% 0 0.00% 0 0.00%

Surface Water 1,035 3 0.29% 3 0.29% 3 0.29%

All Small Systems 1,821 3 0.16% 3 0.16% 3 0.16%

Ground Water 1,377 1 0.07% 1 0.07% 1 0.07%

Surface Water 1,166 0 0.00% 0 0.00% 0 0.00%

All Large Systems 2,543 1 0.04% 1 0.04% 1 0.04%

Ground Water 1,997 0 0.00% 0 0.00% 0 0.00%

Surface Water 4,738 1 0.02% 1 0.02% 1 0.02%

All Very Large Systems 6,735 1 0.01% 1 0.01% 1 0.01%

All Water Systems 11,099 5 0.05% 5 0.05% 5 0.05%

Source Water Type

Concentration Value of Detections (μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people)

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems

Source Water Type Total # of 

Samples

Samples with Detections Samples with Detections 

> 1⁄2 HRL (0.2 μg/L)

Samples with Detections 

> HRL (0.4 μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people)

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 36 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

1 7,705 16 104,148

(0.42%) (1.17%) (0.42%) (1.17%)

1 7,705 16 104,148

(0.21%) (0.64%) (0.03%) (0.22%)

1 73,993 10 436,824

(0.66%) (1.12%) (0.66%) (1.12%)

0 0 0 0

(0%) (0%) (0%) (0%)

1 73,993 10 436,824

(0.31%) (0.53%) (0.35%) (0.52%)

0 0 0 0

(0%) (0%) (0%) (0%)

1 3,828,700 1 3,828,700

(0.3%) (3.07%) (0.3%) (3.07%)

1 3,828,700 1 3,828,700

(0.25%) (2.7%) (0.25%) (2.7%)

3 3,910,398 27 4,369,672

(0.25%) (2.49%) (0.04%) (1.61%)

All Systems

All Water Systems 1,198 157,219,620 64,954 272,002,430

Surface Water 335 124,711,765 335 124,711,765

All Very Large Systems 398 141,981,684 398 141,981,684

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919 63 17,269,919

169 7,444,830 1,366 44,536,172

All Large Systems 320 14,029,015 2,872 83,406,444

Table D15c. Alachlor ESA National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 – Summary of System 

and Population Served Data -- All Detections 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections in the UCMR 2 

Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364 57,818 37,685,557

Surface Water 240 660,557 3,866 8,928,745

All Small Systems 480 1,208,921 61,684 46,614,302

1 National estimates for the small and large systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages 

and national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems 

are based directly on the UCMR 2 results, since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey Monitoring. Due 

to rounding, some calculations may appear to be slightly off.

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184 1,506 38,870,272

Surface Water
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 37 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

1 7,705 16 104,148

(0.42%) (1.17%) (0.42%) (1.17%)

1 7,705 16 104,148

(0.21%) (0.64%) (0.03%) (0.22%)

1 73,993 10 436,824

(0.66%) (1.12%) (0.66%) (1.12%)

0 0 0 0

(0%) (0%) (0%) (0%)

1 73,993 10 436,824

(0.31%) (0.53%) (0.35%) (0.52%)

0 0 0 0

(0%) (0%) (0%) (0%)

1 3,828,700 1 3,828,700

(0.3%) (3.07%) (0.3%) (3.07%)

1 3,828,700 1 3,828,700

(0.25%) (2.7%) (0.25%) (2.7%)

3 3,910,398 27 4,369,672

(0.25%) (2.49%) (0.04%) (1.61%)

All Systems

All Water Systems 1,198 157,219,620 64,954 272,002,430

Surface Water 335 124,711,765 335 124,711,765

All Very Large Systems 398 141,981,684 398 141,981,684

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919 63 17,269,919

Surface Water 169 7,444,830 1,366 44,536,172

All Large Systems 320 14,029,015 2,872 83,406,444

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184 1,506 38,870,272

Surface Water 240 660,557 3,866 8,928,745

All Small Systems 480 1,208,921 61,684 46,614,302

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364 57,818 37,685,557

Table D15d. Alachlor ESA National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 – Summary of System 

and Population Served Data -- Detections > 1/2 HRL 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections > 1/2 HRL (0.2 

μg/L) in the UCMR 2 Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections > 1/2 HRL (0.2 

μg/L)

1 National estimates for the small and large systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages 

and national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems 

are based directly on the UCMR 2 results, since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey Monitoring. Due 

to rounding, some calculations may appear to be slightly off.
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 38 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

1 7,705 16 104,148

(0.42%) (1.17%) (0.42%) (1.17%)

1 7,705 16 104,148

(0.21%) (0.64%) (0.03%) (0.22%)

1 73,993 10 436,824

(0.66%) (1.12%) (0.66%) (1.12%)

0 0 0 0

(0%) (0%) (0%) (0%)

1 73,993 10 436,824

(0.31%) (0.53%) (0.35%) (0.52%)

0 0 0 0

(0%) (0%) (0%) (0%)

1 3,828,700 1 3,828,700

(0.3%) (3.07%) (0.3%) (3.07%)

1 3,828,700 1 3,828,700

(0.25%) (2.7%) (0.25%) (2.7%)

3 3,910,398 27 4,369,672

(0.25%) (2.49%) (0.04%) (1.61%)

All Systems

All Water Systems 1,198 157,219,620 64,954 272,002,430

Surface Water 335 124,711,765 335 124,711,765

All Very Large Systems 398 141,981,684 398 141,981,684

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919 63 17,269,919

Surface Water 169 7,444,830 1,366 44,536,172

All Large Systems 320 14,029,015 2,872 83,406,444

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184 1,506 38,870,272

Surface Water 240 660,557 3,866 8,928,745

All Small Systems 480 1,208,921 61,684 46,614,302

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364 57,818 37,685,557

Table D15e. Alachlor ESA National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 – Summary of System 

and Population Served Data -- Detections > HRL 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections > HRL (0.4 μg/L) in 

the UCMR 2 Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections > HRL (0.4 μg/L)

1 National estimates for the small and large systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages 

and national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems 

are based directly on the UCMR 2 results, since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey Monitoring. Due 

to rounding, some calculations may appear to be slightly off.
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 39 of 74

Table D16a. Alachlor OA Occurrence Data from UCMR 2 Screening Survey thru July 2011 - Summary of Detected Concentrations

Minimum Median 90th Percentile 99th 

Percentile Maximum

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Small Systems N/A N/A N/A N/A N/A

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Large Systems N/A N/A N/A N/A N/A

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Very Large Systems N/A N/A N/A N/A N/A

All Water Systems N/A N/A N/A N/A N/A

Table D16b. Alachlor OA National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 - Summary of Samples

Number Percent Number Percent Number Percent

Ground Water 786 0 0.00% 0 0.00% 0 0.00%

Surface Water 1,035 0 0.00% 0 0.00% 0 0.00%

All Small Systems 1,821 0 0.00% 0 0.00% 0 0.00%

Ground Water 1,377 0 0.00% 0 0.00% 0 0.00%

Surface Water 1,166 0 0.00% 0 0.00% 0 0.00%

All Large Systems 2,543 0 0.00% 0 0.00% 0 0.00%

Ground Water 1,997 0 0.00% 0 0.00% 0 0.00%

Surface Water 4,739 0 0.00% 0 0.00% 0 0.00%

All Very Large Systems 6,736 0 0.00% 0 0.00% 0 0.00%

All Water Systems 11,100 0 0.00% 0 0.00% 0 0.00%

Source Water Type

Concentration Value of Detections (μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people)

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems

Source Water Type Total # of 

Samples

Samples with Detections Samples with Detections 

> 1⁄2 HRL (0.2 μg/L)

Samples with Detections 

> HRL (0.4 μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people)

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 40 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

All Systems

All Water Systems 1,198 157,219,620 64,954 272,002,430

Surface Water 335 124,711,765 335 124,711,765

All Very Large Systems 398 141,981,684 398 141,981,684

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919 63 17,269,919

Surface Water 169 7,444,830 1,366 44,536,172

All Large Systems 320 14,029,015 2,872 83,406,444

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184 1,506 38,870,272

3,866 8,928,745

All Small Systems 480 1,208,921 61,684 46,614,302

Table D16c. Alachlor OA National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 – Summary of System and 

Population Served Data -- All Detections 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections in the UCMR 2 

Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections

1 National estimates for the small and large systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages 

and national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems 

are based directly on the UCMR 2 results, since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey Monitoring. Due 

to rounding, some calculations may appear to be slightly off.

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364 57,818 37,685,557

Surface Water 240 660,557
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 41 of 74

Table D17a. Metolachlor Occurrence Data from UCMR 2 Screening Survey thru July 2011 - Summary of Detected Concentrations

Minimum Median 90th Percentile 99th 

Percentile Maximum

Ground Water N/A N/A N/A N/A N/A

Surface Water 1.152 1.942175 2.574315 2.7165465 2.73235

All Small Systems 1.152 1.942175 2.574315 2.7165465 2.73235

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Large Systems N/A N/A N/A N/A N/A

Ground Water N/A N/A N/A N/A N/A

Surface Water 1.4 1.4 1.4 1.4 1.4

All Very Large Systems 1.4 1.4 1.4 1.4 1.4

All Water Systems 1.152 1.4 2.46588 2.705703 2.73235

Table D17b. Metolachlor National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 - Summary of Samples

Number Percent Number Percent Number Percent

Ground Water 788 0 0.00% 0 0.00% 0 0.00%

Surface Water 1,040 2 0.19% 0 0.00% 0 0.00%

All Small Systems 1,828 2 0.11% 0 0.00% 0 0.00%

Ground Water 1,382 0 0.00% 0 0.00% 0 0.00%

Surface Water 1,178 0 0.00% 0 0.00% 0 0.00%

All Large Systems 2,560 0 0.00% 0 0.00% 0 0.00%

Ground Water 2,009 0 0.00% 0 0.00% 0 0.00%

Surface Water 4,740 1 0.02% 0 0.00% 0 0.00%

All Very Large Systems 6,749 1 0.01% 0 0.00% 0 0.00%

All Water Systems 11,137 3 0.03% 0 0.00% 0 0.00%

Source Water Type

Concentration Value of Detections (μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people)

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems

Source Water Type Total # of 

Samples

Samples with Detections Samples with Detections 

> 1⁄2 HRL (350 μg/L)

Samples with Detections 

> HRL (700 μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people)

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 42 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

2 2,240 32 30,278

(0.83%) (0.34%) (0.83%) (0.34%)

2 2,240 32 30,278

(0.42%) (0.19%) (0.05%) (0.06%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

1 105,270 1 105,270

(0.3%) (0.08%) (0.3%) (0.08%)

1 105,270 1 105,270

(0.25%) (0.07%) (0.25%) (0.07%)

3 107,510 33 135,548

(0.25%) (0.07%) (0.05%) (0.05%)

All Systems

All Water Systems 1,198 157,219,620 64,954 272,002,430

Surface Water 335 124,711,765 335 124,711,765

All Very Large Systems 398 141,981,684 398 141,981,684

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919 63 17,269,919

169 7,444,830 1,366 44,536,172

All Large Systems 320 14,029,015 2,872 83,406,444

Table D17c. Metolachlor National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 – Summary of System and 

Population Served Data -- All Detections 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections in the UCMR 2 

Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364 57,818 37,685,557

Surface Water 240 660,557 3,866 8,928,745

All Small Systems 480 1,208,921 61,684 46,614,302

1 National estimates for the small and large systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages 

and national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems 

are based directly on the UCMR 2 results, since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey Monitoring. Due 

to rounding, some calculations may appear to be slightly off.

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184 1,506 38,870,272

Surface Water
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 43 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

All Systems

All Water Systems 1,198 157,219,620 64,954 272,002,430

Surface Water 335 124,711,765 335 124,711,765

All Very Large Systems 398 141,981,684 398 141,981,684

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919 63 17,269,919

Surface Water 169 7,444,830 1,366 44,536,172

All Large Systems 320 14,029,015 2,872 83,406,444

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184 1,506 38,870,272

Surface Water 240 660,557 3,866 8,928,745

All Small Systems 480 1,208,921 61,684 46,614,302

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364 57,818 37,685,557

Table D17d. Metolachlor National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 – Summary of System and 

Population Served Data -- Detections > 1/2 HRL 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections > 1/2 HRL (350 

μg/L) in the UCMR 2 Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections > HRL (350 μg/L)

1 National estimates for the small and large systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages 

and national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems 

are based directly on the UCMR 2 results, since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey Monitoring. Due 

to rounding, some calculations may appear to be slightly off.
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 44 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

All Systems

All Water Systems 1,198 157,219,620 64,954 272,002,430

Surface Water 335 124,711,765 335 124,711,765

All Very Large Systems 398 141,981,684 398 141,981,684

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919 63 17,269,919

Surface Water 169 7,444,830 1,366 44,536,172

All Large Systems 320 14,029,015 2,872 83,406,444

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184 1,506 38,870,272

Surface Water 240 660,557 3,866 8,928,745

All Small Systems 480 1,208,921 61,684 46,614,302

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364 57,818 37,685,557

Table D17e. Metolachlor National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 – Summary of System and 

Population Served Data -- Detections > HRL 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections > HRL (700 μg/L) in 

the UCMR 2 Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections > HRL (700 μg/L)

1 National estimates for the small and large systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages 

and national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems 

are based directly on the UCMR 2 results, since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey Monitoring. Due 

to rounding, some calculations may appear to be slightly off.
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 45 of 74

Table D18a. Metolachlor ESA Occurrence Data from UCMR 2 Screening Survey thru July 2011 - Summary of Detected Concentrations

Minimum Median 90th Percentile 99th 

Percentile Maximum

Ground Water 1.16 1.95 2.711365 3.7813675 3.95455

Surface Water 1.02381 1.11739 1.4 1.4 1.4

All Small Systems 1.02381 1.8375 2.62273 3.72364 3.95455

Ground Water 1.48261 1.87095 2.13864 2.20614 2.21364

Surface Water 1 1.1 1.3 1.3 1.3

All Large Systems 1 1.25 1.945102 2.18614 2.21364

Ground Water 1.03 1.168 3.0236 3.29576 3.326

Surface Water 1.1 1.24375 2.02 2.182 2.2

All Very Large Systems 1.03 1.1875 2.7112 3.25796 3.326

All Water Systems 1 1.441305 2.619857 3.6339895 3.95455

Table D18b. Metolachlor ESA National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 - Summary of Samples

Number Percent Number Percent Number Percent

Ground Water 786 16 2.04% 0 0.00% 0 0.00%

Surface Water 1,035 5 0.48% 0 0.00% 0 0.00%

All Small Systems 1,821 21 1.15% 0 0.00% 0 0.00%

Ground Water 1,377 4 0.29% 0 0.00% 0 0.00%

Surface Water 1,166 8 0.69% 0 0.00% 0 0.00%

All Large Systems 2,543 12 0.47% 0 0.00% 0 0.00%

Ground Water 1,997 9 0.45% 0 0.00% 0 0.00%

Surface Water 4,739 10 0.21% 0 0.00% 0 0.00%

All Very Large Systems 6,736 19 0.28% 0 0.00% 0 0.00%

All Water Systems 11,100 52 0.47% 0 0.00% 0 0.00%

Source Water Type

Concentration Value of Detections (μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people)

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems

Source Water Type Total # of 

Samples

Samples with Detections Samples with Detections 

> 1⁄2 HRL (350 μg/L)

Samples with Detections 

> HRL (700 μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people)

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 46 of 74

Systems Population Systems Population Systems Population Systems Population

5 17,540 1,205 1,205,412

(2.08%) (3.2%) (2.08%) (3.2%)

3 17,498 48 236,514

(1.25%) (2.65%) (1.25%) (2.65%)

8 35,038 1,253 1,441,926

(1.67%) (2.9%) (2.03%) (3.09%)

1 73,993 10 436,824

(0.66%) (1.12%) (0.66%) (1.12%)

3 138,897 24 830,904

(1.78%) (1.87%) (1.78%) (1.87%)

4 212,890 34 1,267,728

(1.25%) (1.52%) (1.19%) (1.52%)

1 1,045,522 1 1,045,522

(1.59%) (6.05%) (1.59%) (6.05%)

6 4,580,535 6 4,580,535

(1.79%) (3.67%) (1.79%) (3.67%)

7 5,626,057 7 5,626,057

(1.76%) (3.96%) (1.76%) (3.96%)

19 5,873,985 1,294 8,335,711

(1.59%) (3.74%) (1.99%) (3.06%)

All Systems

All Water Systems 1,198 157,219,620 64,954 272,002,430

Surface Water 335 124,711,765 335 124,711,765

All Very Large Systems 398 141,981,684 398 141,981,684

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919 63 17,269,919

169 7,444,830 1,366 44,536,172

All Large Systems 320 14,029,015 2,872 83,406,444

Table D18c. Metolachlor ESA National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 – Summary of 

System and Population Served Data -- All Detections 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections in the UCMR 2 

Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364 57,818 37,685,557

Surface Water 240 660,557 3,866 8,928,745

All Small Systems 480 1,208,921 61,684 46,614,302

1 National estimates for the small and large systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages 

and national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems 

are based directly on the UCMR 2 results, since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey Monitoring. Due 

to rounding, some calculations may appear to be slightly off.

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184 1,506 38,870,272

Surface Water
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 47 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

All Systems

All Water Systems 1,198 157,219,620 64,954 272,002,430

Surface Water 335 124,711,765 335 124,711,765

All Very Large Systems 398 141,981,684 398 141,981,684

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919 63 17,269,919

Surface Water 169 7,444,830 1,366 44,536,172

All Large Systems 320 14,029,015 2,872 83,406,444

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184 1,506 38,870,272

Surface Water 240 660,557 3,866 8,928,745

All Small Systems 480 1,208,921 61,684 46,614,302

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364 57,818 37,685,557

Table D18d. Metolachlor ESA National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 – Summary of 

System and Population Served Data -- Detections > 1/2 HRL 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections > 1/2 HRL (350 

μg/L) in the UCMR 2 Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections > HRL (350 μg/L)

1 National estimates for the small and large systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages 

and national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems 

are based directly on the UCMR 2 results, since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey Monitoring. Due 

to rounding, some calculations may appear to be slightly off.
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 48 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

All Systems

All Water Systems 1,198 157,219,620 64,954 272,002,430

Surface Water 335 124,711,765 335 124,711,765

All Very Large Systems 398 141,981,684 398 141,981,684

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919 63 17,269,919

Surface Water 169 7,444,830 1,366 44,536,172

All Large Systems 320 14,029,015 2,872 83,406,444

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184 1,506 38,870,272

Surface Water 240 660,557 3,866 8,928,745

All Small Systems 480 1,208,921 61,684 46,614,302

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364 57,818 37,685,557

Table D18e. Metolachlor ESA National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 – Summary of 

System and Population Served Data -- Detections > HRL 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections > HRL (700 μg/L) in 

the UCMR 2 Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections > HRL (700 μg/L)

1 National estimates for the small and large systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages 

and national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems 

are based directly on the UCMR 2 results, since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey Monitoring. Due 

to rounding, some calculations may appear to be slightly off.
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 49 of 74

Table D19a. Metolachlor OA Occurrence Data from UCMR 2 Screening Survey thru July 2011 - Summary of Detected Concentrations

Minimum Median 90th Percentile 99th 

Percentile Maximum

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Small Systems N/A N/A N/A N/A N/A

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Large Systems N/A N/A N/A N/A N/A

Ground Water 2.502 3.078 3.4468 3.52978 3.539

Surface Water N/A N/A N/A N/A N/A

All Very Large Systems 2.502 3.078 3.4468 3.52978 3.539

All Water Systems 2.502 3.078 3.4468 3.52978 3.539

Table D19b. Metolachlor OA National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 - Summary of Samples

Number Percent Number Percent Number Percent

Ground Water 786 0 0.00% 0 0.00% 0 0.00%

Surface Water 1,035 0 0.00% 0 0.00% 0 0.00%

All Small Systems 1,821 0 0.00% 0 0.00% 0 0.00%

Ground Water 1,377 0 0.00% 0 0.00% 0 0.00%

Surface Water 1,166 0 0.00% 0 0.00% 0 0.00%

All Large Systems 2,543 0 0.00% 0 0.00% 0 0.00%

Ground Water 1,997 3 0.15% 0 0.00% 0 0.00%

Surface Water 4,739 0 0.00% 0 0.00% 0 0.00%

All Very Large Systems 6,736 3 0.04% 0 0.00% 0 0.00%

All Water Systems 11,100 3 0.03% 0 0.00% 0 0.00%

Source Water Type

Concentration Value of Detections (μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people)

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems

Source Water Type Total # of 

Samples

Samples with Detections Samples with Detections 

> 1⁄2 HRL (350 μg/L)

Samples with Detections 

> HRL (700 μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people)

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 50 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

1 1,045,522 1 1,045,522

(1.59%) (6.05%) (1.59%) (6.05%)

0 0 0 0

(0%) (0%) (0%) (0%)

1 1,045,522 1 1,045,522

(0.25%) (0.74%) (0.25%) (0.74%)

1 1,045,522 1 1,045,522

(0.08%) (0.67%) (0%) (0.38%)

All Systems

All Water Systems 1,198 157,219,620 64,954 272,002,430

Surface Water 335 124,711,765 335 124,711,765

All Very Large Systems 398 141,981,684 398 141,981,684

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919 63 17,269,919

169 7,444,830 1,366 44,536,172

All Large Systems 320 14,029,015 2,872 83,406,444

Table D19c. Metolachlor OA National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 – Summary of System 

and Population Served Data -- All Detections 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections in the UCMR 2 

Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364 57,818 37,685,557

Surface Water 240 660,557 3,866 8,928,745

All Small Systems 480 1,208,921 61,684 46,614,302

1 National estimates for the small and large systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages 

and national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems 

are based directly on the UCMR 2 results, since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey Monitoring. Due 

to rounding, some calculations may appear to be slightly off.

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184 1,506 38,870,272

Surface Water
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 51 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

All Systems

All Water Systems 1,198 157,219,620 64,954 272,002,430

Surface Water 335 124,711,765 335 124,711,765

All Very Large Systems 398 141,981,684 398 141,981,684

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919 63 17,269,919

Surface Water 169 7,444,830 1,366 44,536,172

All Large Systems 320 14,029,015 2,872 83,406,444

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184 1,506 38,870,272

Surface Water 240 660,557 3,866 8,928,745

All Small Systems 480 1,208,921 61,684 46,614,302

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364 57,818 37,685,557

Table D19d. Metolachlor OA National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 – Summary of System 

and Population Served Data -- Detections > 1/2 HRL 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections > 1/2 HRL (350 

μg/L) in the UCMR 2 Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections > HRL (350 μg/L)

1 National estimates for the small and large systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages 

and national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems 

are based directly on the UCMR 2 results, since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey Monitoring. Due 

to rounding, some calculations may appear to be slightly off.
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 52 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

All Systems

All Water Systems 1,198 157,219,620 64,954 272,002,430

Surface Water 335 124,711,765 335 124,711,765

All Very Large Systems 398 141,981,684 398 141,981,684

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919 63 17,269,919

Surface Water 169 7,444,830 1,366 44,536,172

All Large Systems 320 14,029,015 2,872 83,406,444

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184 1,506 38,870,272

Surface Water 240 660,557 3,866 8,928,745

All Small Systems 480 1,208,921 61,684 46,614,302

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364 57,818 37,685,557

Table D19e. Metolachlor OA National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 – Summary of System 

and Population Served Data -- Detections > HRL 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections > HRL (700 μg/L) in 

the UCMR 2 Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections > HRL (700 μg/L)

1 National estimates for the small and large systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages 

and national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems 

are based directly on the UCMR 2 results, since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey Monitoring. Due 

to rounding, some calculations may appear to be slightly off.
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 53 of 74

Table D20a. NDBA Occurrence Data from UCMR 2 Screening Survey thru July 2011 - Summary of Detected Concentrations

Minimum Median 90th Percentile 99th 

Percentile Maximum

Ground Water 0.004 0.006 0.018 0.020 0.02062

Surface Water N/A N/A N/A N/A N/A

All Small Systems 0.004 0.006 0.018 0.020 0.02062

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Large Systems N/A N/A N/A N/A N/A

Ground Water 0.00442 0.007 0.009 0.009 0.0093

Surface Water 0.0048 0.009 0.010 0.010 0.01

All Very Large Systems 0.00442 0.008 0.010 0.010 0.01

All Water Systems 0.004 0.007 0.012 0.020 0.02062

Table D20b. NDBA National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 - Summary of Samples

Number Percent Number Percent Number Percent

Ground Water 1,237 3 0.24% 1 0.08% 0 0.00%

Surface Water 1,996 0 0.00% 0 0.00% 0 0.00%

All Small Systems 3,233 3 0.09% 1 0.03% 0 0.00%

Ground Water 1,926 0 0.00% 0 0.00% 0 0.00%

Surface Water 2,089 0 0.00% 0 0.00% 0 0.00%

All Large Systems 4,015 0 0.00% 0 0.00% 0 0.00%

Ground Water 2,964 3 0.10% 0 0.00% 0 0.00%

Surface Water 7,831 3 0.04% 0 0.00% 0 0.00%

All Very Large Systems 10,795 6 0.06% 0 0.00% 0 0.00%

All Water Systems 18,043 9 0.05% 1 0.01% 0 0.00%

Source Water Type

Concentration Value of Detections (μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people)

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems

Source Water Type Total # of 

Samples

Samples with Detections Samples with Detections 

> 1⁄2 HRL (0.015 μg/L)

Samples with Detections 

> HRL (0.03 μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people)

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 54 of 74

Systems Population Systems Population Systems Population Systems Population

2 14,292 482 982,198

(0.83%) (2.61%) (0.83%) (2.61%)

0 0 0 0

(0%) (0%) (0%) (0%)

2 14,292 482 982,198

(0.42%) (1.18%) (0.78%) (2.11%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

1 1,045,522 1 1,045,522

(1.59%) (6.05%) (1.59%) (6.05%)

2 626,169 2 626,169

(0.6%) (0.5%) (0.6%) (0.5%)

3 1,671,691 3 1,671,691

(0.75%) (1.18%) (0.75%) (1.18%)

5 1,685,983 485 2,653,889

(0.42%) (1.07%) (0.75%) (0.98%)

All Systems

All Water Systems 1,198 157,219,620 64,954 272,002,430

Surface Water 335 124,711,765 335 124,711,765

All Very Large Systems 398 141,981,684 398 141,981,684

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919 63 17,269,919

Table D20c. NDBA National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 – Summary of System and 

Population Served Data -- All Detections 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections in the UCMR 2 

Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364 57,818 37,685,557

Surface Water 240 660,557 3,866 8,928,745

All Small Systems 480 1,208,921 61,684 46,614,302

14,029,015 2,872 83,406,444

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184 1,506 38,870,272

1 National estimates for the small and large systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages 

and national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems 

are based directly on the UCMR 2 results, since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey Monitoring. Due 

to rounding, some calculations may appear to be slightly off.

Surface Water 169 7,444,830 1,366 44,536,172

All Large Systems 320
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 55 of 74

Systems Population Systems Population Systems Population Systems Population

1 6,792 241 466,771

(0.42%) (1.24%) (0.42%) (1.24%)

0 0 0 0

(0%) (0%) (0%) (0%)

1 6,792 241 466,771

(0.21%) (0.56%) (0.39%) (1%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

1 6,792 241 466,771

(0.08%) (0.004%) (0.37%) (0.17%)

All Systems

All Water Systems 1,198 157,219,620 64,954 272,002,430

Surface Water 335 124,711,765 335 124,711,765

All Very Large Systems 398 141,981,684 398 141,981,684

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919 63 17,269,919

Surface Water 169 7,444,830 1,366 44,536,172

All Large Systems 320 14,029,015 2,872 83,406,444

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184 1,506 38,870,272

Surface Water 240 660,557 3,866 8,928,745

All Small Systems 480 1,208,921 61,684 46,614,302

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364 57,818 37,685,557

Table D20d. NDBA National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 – Summary of System and 

Population Served Data -- Detections > 1/2 HRL 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections > 1/2 HRL (0.015 

μg/L) in the UCMR 2 Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections > 1/2 HRL (0.015 

μg/L)

1 National estimates for the small and large systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages 

and national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems 

are based directly on the UCMR 2 results, since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey Monitoring. Due 

to rounding, some calculations may appear to be slightly off.
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 56 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

All Systems

All Water Systems 1,198 157,219,620 64,954 272,002,430

Surface Water 335 124,711,765 335 124,711,765

All Very Large Systems 398 141,981,684 398 141,981,684

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919 63 17,269,919

Surface Water 169 7,444,830 1,366 44,536,172

All Large Systems 320 14,029,015 2,872 83,406,444

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184 1,506 38,870,272

Surface Water 240 660,557 3,866 8,928,745

All Small Systems 480 1,208,921 61,684 46,614,302

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364 57,818 37,685,557

Table D20e. NDBA National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 – Summary of System and 

Population Served Data -- Detections > HRL 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections > HRL (0.03 μg/L) 

in the UCMR 2 Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections > HRL (0.03 μg/L)

1 National estimates for the small and large systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages 

and national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems 

are based directly on the UCMR 2 results, since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey Monitoring. Due 

to rounding, some calculations may appear to be slightly off.
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 57 of 74

Table D21a. NDEA Occurrence Data from UCMR 2 Screening Survey thru July 2011 - Summary of Detected Concentrations

Minimum Median 90th Percentile 99th 

Percentile Maximum

Ground Water 0.009 0.009 0.009 0.009 0.009

Surface Water N/A N/A N/A N/A N/A

All Small Systems 0.009 0.009 0.009 0.009 0.009

Ground Water 0.0051 0.005 0.006 0.006 0.0063

Surface Water 0.0057 0.012 0.044 0.049 0.05

All Large Systems 0.0051 0.009 0.040 0.049 0.05

Ground Water 0.0053 0.006 0.013 0.021 0.022

Surface Water 0.005 0.008 0.029 0.096 0.1

All Very Large Systems 0.005 0.007 0.027 0.095 0.1

All Water Systems 0.005 0.007 0.031 0.093 0.1

Table D21b. NDEA National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 - Summary of Samples

Number Percent Number Percent Number Percent

Ground Water 1,237 1 0.08% 1 0.08% 1 0.08%

Surface Water 1,996 0 0.00% 0 0.00% 0 0.00%

All Small Systems 3,233 1 0.03% 1 0.03% 1 0.03%

Ground Water 1,914 3 0.16% 3 0.16% 3 0.16%

Surface Water 2,089 6 0.29% 6 0.29% 6 0.29%

All Large Systems 4,003 9 0.22% 9 0.22% 9 0.22%

Ground Water 2,966 7 0.24% 7 0.24% 7 0.24%

Surface Water 7,836 29 0.37% 29 0.37% 29 0.37%

All Very Large Systems 10,802 36 0.33% 36 0.33% 36 0.33%

All Water Systems 18,038 46 0.26% 46 0.26% 46 0.26%

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems

Total # of 

Samples

Samples with Detections Samples with Detections 

> 1⁄2 HRL (0.0002 μg/L)

Samples with Detections 

> HRL (0.0004 μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people)

Source Water Type

Concentration Value of Detections (μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people)

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems

Source Water Type
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 58 of 74

Systems Population Systems Population Systems Population Systems Population

1 6,575 241 451,858

(0.42%) (1.2%) (0.42%) (1.2%)

0 0 0 0

(0%) (0%) (0%) (0%)

1 6,575 241 451,858

(0.21%) (0.54%) (0.39%) (0.97%)

1 93,660 10 552,930

(0.66%) (1.42%) (0.66%) (1.42%)

3 148,608 24 888,995

(1.78%) (2%) (1.78%) (2%)

4 242,268 34 1,441,924

(1.25%) (1.73%) (1.19%) (1.73%)

5 668,861 5 668,861

(7.94%) (3.87%) (7.94%) (3.87%)

16 10,314,490 16 10,314,490

(4.78%) (8.27%) (4.78%) (8.27%)

21 10,983,351 21 10,983,351

(5.28%) (7.74%) (5.28%) (7.74%)

26 11,232,194 296 12,877,133

(2.17%) (7.14%) (0.46%) (4.73%) All Water Systems 1,198 157,219,620 64,954 272,002,430

All Very Large Systems 398 141,981,684 398 141,981,684

All Systems

Ground Water 63 17,269,919 63 17,269,919

Surface Water 335 124,711,765 335 124,711,765

All Large Systems 320 14,029,015 2,872 83,406,444

Very Large Systems (serving > 100,000 people) -- CENSUS

Table D21c. NDEA National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 – Summary of System and 

Population Served Data -- All Detections 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections in the UCMR 2 

Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections

1,208,921 61,684 46,614,302

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364 57,818 37,685,557

6,584,184 1,506 38,870,272

Surface Water 240 660,557 3,866 8,928,745

All Small Systems 480

Surface Water 169 7,444,830 1,366 44,536,172

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151

1 National estimates for the small and large systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages 

and national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems 

are based directly on the UCMR 2 results, since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey Monitoring. Due 

to rounding, some calculations may appear to be slightly off.
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 59 of 74

Systems Population Systems Population Systems Population Systems Population

1 6,575 241 451,858

(0.42%) (1.2%) (0.42%) (1.2%)

0 0 0 0

(0%) (0%) (0%) (0%)

1 6,575 241 451,858

(0.21%) (0.54%) (0.39%) (0.97%)

1 93,660 10 552,930

(0.66%) (1.42%) (0.66%) (1.42%)

3 148,608 24 888,995

(1.78%) (2%) (1.78%) (2%)

4 242,268 34 1,441,924

(1.25%) (1.73%) (1.19%) (1.73%)

5 668,861 5 668,861

(7.94%) (3.87%) (7.94%) (3.87%)

16 10,314,490 16 10,314,490

(4.78%) (8.27%) (4.78%) (8.27%)

21 10,983,351 21 10,983,351

(5.28%) (7.74%) (5.28%) (7.74%)

26 11,232,194 296 12,877,133

(2.17%) (7.14%) (0.46%) (4.73%) All Water Systems 1,198 157,219,620 64,954 272,002,430

All Very Large Systems 398 141,981,684 398 141,981,684

All Systems

Ground Water 63 17,269,919 63 17,269,919

Surface Water 335 124,711,765 335 124,711,765

All Large Systems 320 14,029,015 2,872 83,406,444

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 151 6,584,184 1,506 38,870,272

Surface Water 169 7,444,830 1,366 44,536,172

All Small Systems 480 1,208,921 61,684 46,614,302

Large Systems (serving 10,001 - 100,000 people)

Ground Water 240 548,364 57,818 37,685,557

Surface Water 240 660,557 3,866 8,928,745

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections > 1/2 HRL (0.0002 

μg/L) in the UCMR 2 Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections > 1/2 HRL (0.0002 

μg/L)

Small Systems (serving ≤ 10,000 people)

Table D21d. NDEA National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 – Summary of System and 

Population Served Data -- Detections > 1/2 HRL 

1 National estimates for the small and large systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages 

and national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems 

are based directly on the UCMR 2 results, since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey Monitoring. Due 

to rounding, some calculations may appear to be slightly off.
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 60 of 74

Systems Population Systems Population Systems Population Systems Population

1 6,575 241 451,858

(0.42%) (1.2%) (0.42%) (1.2%)

0 0 0 0

(0%) (0%) (0%) (0%)

1 6,575 241 451,858

(0.21%) (0.54%) (0.39%) (0.97%)

1 93,660 10 552,930

(0.66%) (1.42%) (0.66%) (1.42%)

3 148,608 24 888,995

(1.78%) (2%) (1.78%) (2%)

4 242,268 34 1,441,924

(1.25%) (1.73%) (1.19%) (1.73%)

5 668,861 5 668,861

(7.94%) (3.87%) (7.94%) (3.87%)

16 10,314,490 16 10,314,490

(4.78%) (8.27%) (4.78%) (8.27%)

21 10,983,351 21 10,983,351

(5.28%) (7.74%) (5.28%) (7.74%)

26 11,232,194 296 12,877,133

(2.17%) (7.14%) (0.46%) (4.73%) All Water Systems 1,198 157,219,620 64,954 272,002,430

All Very Large Systems 398 141,981,684 398 141,981,684

All Systems

Ground Water 63 17,269,919 63 17,269,919

Surface Water 335 124,711,765 335 124,711,765

All Large Systems 320 14,029,015 2,872 83,406,444

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 151 6,584,184 1,506 38,870,272

Surface Water 169 7,444,830 1,366 44,536,172

All Small Systems 480 1,208,921 61,684 46,614,302

Large Systems (serving 10,001 - 100,000 people)

Ground Water 240 548,364 57,818 37,685,557

Surface Water 240 660,557 3,866 8,928,745

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections > HRL (0.0004 

μg/L) in the UCMR 2 Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections > HRL (0.0004 

μg/L)

Small Systems (serving ≤ 10,000 people)

Table D21e. NDEA National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 – Summary of System and 

Population Served Data -- Detections > HRL 

1 National estimates for the small and large systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages 

and national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems 

are based directly on the UCMR 2 results, since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey Monitoring. Due 

to rounding, some calculations may appear to be slightly off.
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 61 of 74

Table D22a. NDMA Occurrence Data from UCMR 2 Screening Survey thru July 2011 - Summary of Detected Concentrations

Minimum Median 90th Percentile 99th 

Percentile Maximum

Ground Water 0.002 0.004 0.007 0.009 0.0094

Surface Water 0.002 0.006 0.032 0.125 0.63

All Small Systems 0.002 0.006 0.031 0.122 0.63

Ground Water 0.002 0.004 0.005 0.010 0.01

Surface Water 0.002 0.005 0.016 0.052 0.0656

All Large Systems 0.002 0.004 0.015 0.048 0.0656

Ground Water 0.002 0.003 0.005 0.011 0.01343

Surface Water 0.002 0.004 0.015 0.044 0.094

All Very Large Systems 0.002 0.004 0.014 0.042 0.094

All Water Systems 0.002 0.004 0.016 0.064 0.63

Table D22b. NDMA National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 - Summary of Samples

Number Percent Number Percent Number Percent

Ground Water 1,237 14 1.13% 14 1.13% 14 1.13%

Surface Water 1,996 326 16.33% 326 16.33% 326 16.33%

All Small Systems 3,233 340 10.52% 340 10.52% 340 10.52%

Ground Water 1,926 48 2.49% 48 2.49% 48 2.49%

Surface Water 2,089 305 14.60% 305 14.60% 305 14.60%

All Large Systems 4,015 353 8.79% 353 8.79% 353 8.79%

Ground Water 2,964 52 1.75% 52 1.75% 52 1.75%

Surface Water 7,828 1,096 14.00% 1,096 14.00% 1,096 14.00%

All Very Large Systems 10,792 1,148 10.64% 1,148 10.64% 1,148 10.64%

All Water Systems 18,040 1,841 10.21% 1,841 10.21% 1,841 10.21%

Source Water Type

Concentration Value of Detections (μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people)

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems

Source Water Type Total # of 

Samples

Samples with Detections Samples with Detections 

> 1⁄2 HRL (0.0003 μg/L)

Samples with Detections 

> HRL (0.0006 μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people)

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 62 of 74

Systems Population Systems Population Systems Population Systems Population

10 26,059 2,409 1,790,869

(4.17%) (4.75%) (4.17%) (4.75%)

74 259,285 1,192 3,504,746

(30.83%) (39.25%) (30.83%) (39.25%)

84 285,344 3,601 5,295,615

(17.5%) (23.6%) (5.84%) (11.36%)

13 739,206 130 4,363,960

(8.61%) (11.23%) (8.61%) (11.23%)

58 2,792,925 469 16,707,724

(34.32%) (37.51%) (34.32%) (37.51%)

71 3,532,130 598 21,071,684

(22.19%) (25.18%) (20.84%) (25.26%)

15 5,706,228 15 5,706,228

(23.81%) (33.04%) (23.81%) (33.04%)

154 55,788,062 154 55,788,062

(45.97%) (44.73%) (45.97%) (44.73%)

169 61,494,290 169 61,494,290

(42.46%) (43.31%) (42.46%) (43.31%)

324 65,311,764 4,369 87,861,589

(27.05%) (41.54%) (6.73%) (32.3%)

All Systems

All Water Systems 1,198 157,219,620 64,954 272,002,430

Surface Water 335 124,711,765 335 124,711,765

All Very Large Systems 398 141,981,684 398 141,981,684

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919 63 17,269,919

Table D22c. NDMA National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 – Summary of System and 

Population Served Data -- All Detections 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections in the UCMR 2 

Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364 57,818 37,685,557

Surface Water 240 660,557 3,866 8,928,745

All Small Systems 480 1,208,921 61,684 46,614,302

14,029,015 2,872 83,406,444

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184 1,506 38,870,272

1 National estimates for the small and large systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages 

and national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems 

are based directly on the UCMR 2 results, since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey Monitoring. Due 

to rounding, some calculations may appear to be slightly off.

Surface Water 169 7,444,830 1,366 44,536,172

All Large Systems 320
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 63 of 74

Systems Population Systems Population Systems Population Systems Population

10 26,059 2,409 1,790,869

(4.17%) (4.75%) (4.17%) (4.75%)

74 259,285 1,192 3,504,746

(30.83%) (39.25%) (30.83%) (39.25%)

84 285,344 3,601 5,295,615

(17.5%) (23.6%) (5.84%) (11.36%)

13 739,206 130 4,363,960

(8.61%) (11.23%) (8.61%) (11.23%)

58 2,792,925 469 16,707,724

(34.32%) (37.51%) (34.32%) (37.51%)

71 3,532,130 598 21,071,684

(22.19%) (25.18%) (20.84%) (25.26%)

15 5,706,228 15 5,706,228

(23.81%) (33.04%) (23.81%) (33.04%)

154 55,788,062 154 55,788,062

(45.97%) (44.73%) (45.97%) (44.73%)

169 61,494,290 169 61,494,290

(42.46%) (43.31%) (42.46%) (43.31%)

324 65,311,764 4,369 87,861,589

(27.05%) (41.54%) (6.73%) (32.3%)

All Systems

All Water Systems 1,198 157,219,620 64,954 272,002,430

Surface Water 335 124,711,765 335 124,711,765

All Very Large Systems 398 141,981,684 398 141,981,684

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919 63 17,269,919

Surface Water 169 7,444,830 1,366 44,536,172

All Large Systems 320 14,029,015 2,872 83,406,444

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184 1,506 38,870,272

Surface Water 240 660,557 3,866 8,928,745

All Small Systems 480 1,208,921 61,684 46,614,302

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364 57,818 37,685,557

Table D22d. NDMA National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 – Summary of System and 

Population Served Data -- Detections > 1/2 HRL 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections > 1/2 HRL (0.0003 

μg/L) in the UCMR 2 Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections > 1/2 HRL (0.0003 

μg/L)

1 National estimates for the small and large systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages 

and national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems 

are based directly on the UCMR 2 results, since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey Monitoring. Due 

to rounding, some calculations may appear to be slightly off.
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 64 of 74

Systems Population Systems Population Systems Population Systems Population

10 26,059 2,409 1,790,869

(4.17%) (4.75%) (4.17%) (4.75%)

74 259,285 1,192 3,504,746

(30.83%) (39.25%) (30.83%) (39.25%)

84 285,344 3,601 5,295,615

(17.5%) (23.6%) (5.84%) (11.36%)

13 739,206 130 4,363,960

(8.61%) (11.23%) (8.61%) (11.23%)

58 2,792,925 469 16,707,724

(34.32%) (37.51%) (34.32%) (37.51%)

71 3,532,130 598 21,071,684

(22.19%) (25.18%) (20.84%) (25.26%)

15 5,706,228 15 5,706,228

(23.81%) (33.04%) (23.81%) (33.04%)

154 55,788,062 154 55,788,062

(45.97%) (44.73%) (45.97%) (44.73%)

169 61,494,290 169 61,494,290

(42.46%) (43.31%) (42.46%) (43.31%)

324 65,311,764 4,369 87,861,589

(27.05%) (41.54%) (6.73%) (32.3%)

All Systems

All Water Systems 1,198 157,219,620 64,954 272,002,430

Surface Water 335 124,711,765 335 124,711,765

All Very Large Systems 398 141,981,684 398 141,981,684

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919 63 17,269,919

Surface Water 169 7,444,830 1,366 44,536,172

All Large Systems 320 14,029,015 2,872 83,406,444

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184 1,506 38,870,272

Surface Water 240 660,557 3,866 8,928,745

All Small Systems 480 1,208,921 61,684 46,614,302

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364 57,818 37,685,557

Table D22e. NDMA National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 – Summary of System and 

Population Served Data -- Detections > HRL 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections > HRL (0.0006 

μg/L) in the UCMR 2 Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections > HRL (0.0006 

μg/L)

1 National estimates for the small and large systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages 

and national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems 

are based directly on the UCMR 2 results, since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey Monitoring. Due 

to rounding, some calculations may appear to be slightly off.
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 65 of 74

Table D23a. NDPA Occurrence Data from UCMR 2 Screening Survey thru July 2011 - Summary of Detected Concentrations

Minimum Median 90th Percentile 99th 

Percentile Maximum

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Small Systems N/A N/A N/A N/A N/A

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Large Systems N/A N/A N/A N/A N/A

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Very Large Systems N/A N/A N/A N/A N/A

All Water Systems N/A N/A N/A N/A N/A

Table D23b. NDPA National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 - Summary of Samples

Number Percent Number Percent Number Percent

Ground Water 1,237 0 0.00% 0 0.00% 0 0.00%

Surface Water 1,996 0 0.00% 0 0.00% 0 0.00%

All Small Systems 3,233 0 0.00% 0 0.00% 0 0.00%

Ground Water 1,926 0 0.00% 0 0.00% 0 0.00%

Surface Water 2,089 0 0.00% 0 0.00% 0 0.00%

All Large Systems 4,015 0 0.00% 0 0.00% 0 0.00%

Ground Water 2,966 0 0.00% 0 0.00% 0 0.00%

Surface Water 7,835 0 0.00% 0 0.00% 0 0.00%

All Very Large Systems 10,801 0 0.00% 0 0.00% 0 0.00%

All Water Systems 18,049 0 0.00% 0 0.00% 0 0.00%

Source Water Type

Concentration Value of Detections (μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people)

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems

Source Water Type Total # of 

Samples

Samples with Detections Samples with Detections 

> 1⁄2 HRL (0.0035 μg/L)

Samples with Detections 

> HRL (0.007 μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people)

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 66 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

All Systems

All Water Systems 1,198 157,219,620 64,954 272,002,430

Surface Water 335 124,711,765 335 124,711,765

All Very Large Systems 398 141,981,684 398 141,981,684

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919 63 17,269,919

Surface Water 169 7,444,830 1,366 44,536,172

All Large Systems 320 14,029,015 2,872 83,406,444

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184 1,506 38,870,272

3,866 8,928,745

All Small Systems 480 1,208,921 61,684 46,614,302

Table D23c. NDPA National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 – Summary of System and 

Population Served Data -- All Detections 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections in the UCMR 2 

Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections

1 National estimates for the small and large systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages 

and national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems 

are based directly on the UCMR 2 results, since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey Monitoring. Due 

to rounding, some calculations may appear to be slightly off.

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364 57,818 37,685,557

Surface Water 240 660,557
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 67 of 74

Table D24a. NMEA Occurrence Data from UCMR 2 Screening Survey thru July 2011 - Summary of Detected Concentrations

Minimum Median 90th Percentile 99th 

Percentile Maximum

Ground Water N/A N/A N/A N/A N/A

Surface Water 0.0036 0.0045 0.0048 0.0049 0.0049

All Small Systems 0.0036 0.0045 0.0048 0.0049 0.0049

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Large Systems N/A N/A N/A N/A N/A

Ground Water N/A N/A N/A N/A N/A

Surface Water N/A N/A N/A N/A N/A

All Very Large Systems N/A N/A N/A N/A N/A

All Water Systems 0.0036 0.0045 0.0048 0.0049 0.0049

Table D24b. NMEA National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 - Summary of Samples

Number Percent Number Percent Number Percent

Ground Water 1,237 0 0.00% 0 0.00% 0 0.00%

Surface Water 1,996 3 0.15% 3 0.15% 3 0.15%

All Small Systems 3,233 3 0.09% 3 0.09% 3 0.09%

Ground Water 1,926 0 0.00% 0 0.00% 0 0.00%

Surface Water 2,089 0 0.00% 0 0.00% 0 0.00%

All Large Systems 4,015 0 0.00% 0 0.00% 0 0.00%

Ground Water 2,964 0 0.00% 0 0.00% 0 0.00%

Surface Water 7,831 0 0.00% 0 0.00% 0 0.00%

All Very Large Systems 10,795 0 0.00% 0 0.00% 0 0.00%

All Water Systems 18,043 3 0.02% 3 0.02% 3 0.02%

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems

Total # of 

Samples

Samples with Detections Samples with Detections 

> 1⁄2 HRL (0.0015 μg/L)

Samples with Detections 

> HRL (0.003 μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people)

Source Water Type

Concentration Value of Detections (μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people)

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems

Source Water Type
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 68 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

3 4,480 48 60,556

(1.25%) (0.68%) (1.25%) (0.68%)

3 4,480 48 60,556

(0.63%) (0.37%) (0.08%) (0.13%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

3 4,480 48 60,556

(0.25%) (0.003%) (0.07%) (0.02%) All Water Systems 1,198 157,219,620 64,954 272,002,430

All Very Large Systems 398 141,981,684 398 141,981,684

All Systems

Ground Water 63 17,269,919 63 17,269,919

Surface Water 335 124,711,765 335 124,711,765

All Large Systems 320 14,029,015 2,872 83,406,444

Very Large Systems (serving > 100,000 people) -- CENSUS

Table D24c. NMEA National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 – Summary of System and 

Population Served Data -- All Detections 

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections in the UCMR 2 

Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections

1,208,921 61,684 46,614,302

Small Systems (serving ≤ 10,000 people)

Ground Water 240 548,364 57,818 37,685,557

6,584,184 1,506 38,870,272

Surface Water 240 660,557 3,866 8,928,745

All Small Systems 480

Surface Water 169 7,444,830 1,366 44,536,172

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151

1 National estimates for the small and large systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages 

and national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems 

are based directly on the UCMR 2 results, since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey Monitoring. Due 

to rounding, some calculations may appear to be slightly off.
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 69 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

3 4,480 48 60,556

(1.25%) (0.68%) (1.25%) (0.68%)

3 4,480 48 60,556

(0.63%) (0.37%) (0.08%) (0.13%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

3 4,480 48 60,556

(0.25%) (0.003%) (0.07%) (0.02%) All Water Systems 1,198 157,219,620 64,954 272,002,430

All Very Large Systems 398 141,981,684 398 141,981,684

All Systems

Ground Water 63 17,269,919 63 17,269,919

Surface Water 335 124,711,765 335 124,711,765

All Large Systems 320 14,029,015 2,872 83,406,444

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 151 6,584,184 1,506 38,870,272

Surface Water 169 7,444,830 1,366 44,536,172

All Small Systems 480 1,208,921 61,684 46,614,302

Large Systems (serving 10,001 - 100,000 people)

Ground Water 240 548,364 57,818 37,685,557

Surface Water 240 660,557 3,866 8,928,745

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections > 1/2 HRL (0.0015 

μg/L) in the UCMR 2 Sample

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections > 1/2 HRL (0.0015 

μg/L)

Small Systems (serving ≤ 10,000 people)

Table D24d. NMEA National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 – Summary of System and 

Population Served Data -- Detections > 1/2 HRL 

1 National estimates for the small and large systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages 

and national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems 

are based directly on the UCMR 2 results, since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey Monitoring. Due 

to rounding, some calculations may appear to be slightly off.
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 70 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

3 4,480 48 60,556

(1.25%) (0.68%) (1.25%) (0.68%)

3 4,480 48 60,556

(0.63%) (0.37%) (0.08%) (0.13%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

0 0 0 0

(0%) (0%) (0%) (0%)

3 4,480 48 60,556

(0.25%) (0.003%) (0.07%) (0.02%) All Water Systems 1,198 157,219,620 64,954 272,002,430

All Very Large Systems 398 141,981,684 398 141,981,684

All Systems

Ground Water 63 17,269,919 63 17,269,919

Surface Water 335 124,711,765 335 124,711,765

All Large Systems 320 14,029,015 2,872 83,406,444

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 151 6,584,184 1,506 38,870,272

Surface Water 169 7,444,830 1,366 44,536,172

All Small Systems 480 1,208,921 61,684 46,614,302

Large Systems (serving 10,001 - 100,000 people)

Ground Water 240 548,364 57,818 37,685,557

Surface Water 240 660,557 3,866 8,928,745

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections > HRL (0.003 μg/L) 

in the UCMR 2 Sample

National Inventory

National Estimate1

 of the 

Number (and Percent) of 

Detections > HRL (0.003 

μg/L)

Small Systems (serving ≤ 10,000 people)

Table D24e. NMEA National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 – Summary of System and 

Population Served Data -- Detections > HRL 

1 National estimates for the small and large systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages 

and national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems 

are based directly on the UCMR 2 results, since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey Monitoring. Due 

to rounding, some calculations may appear to be slightly off.
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 71 of 74

Table D25a. NPYR Occurrence Data from UCMR 2 Screening Survey thru July 2011 - Summary of Detected Concentrations

Minimum Median 90th Percentile 99th 

Percentile Maximum

Ground Water N/A N/A N/A N/A N/A

Surface Water 0.00207 0.003 0.005 0.006 0.0061

All Small Systems 0.00207 0.003 0.005 0.006 0.0061

Ground Water N/A N/A N/A N/A N/A

Surface Water 0.0022 0.005 0.008 0.010 0.0097

All Large Systems 0.0022 0.005 0.008 0.010 0.0097

Ground Water 0.0036 0.004 0.004 0.004 0.0036

Surface Water 0.0021 0.005 0.014 0.022 0.0238

All Very Large Systems 0.0021 0.005 0.013 0.022 0.0238

All Water Systems 0.00207 0.004 0.008 0.021 0.0238

Table D25b. NPYR National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 - Summary of Samples

Number Percent Number Percent Number Percent

Ground Water 1,237 0 0.00% 0 0.00% 0 0.00%

Surface Water 1,996 11 0.55% 11 0.55% 11 0.55%

All Small Systems 3,233 11 0.34% 11 0.34% 11 0.34%

Ground Water 1,926 0 0.00% 0 0.00% 0 0.00%

Surface Water 2,089 7 0.34% 7 0.34% 7 0.34%

All Large Systems 4,015 7 0.17% 7 0.17% 7 0.17%

Ground Water 2,964 1 0.03% 1 0.03% 1 0.03%

Surface Water 7,831 22 0.28% 22 0.28% 22 0.28%

All Very Large Systems 10,795 23 0.21% 23 0.21% 23 0.21%

All Water Systems 18,043 41 0.23% 41 0.23% 41 0.23%

Small Systems (serving ≤ 10,000 people)

Source Water Type

Concentration Value of Detections (μg/L)

Small Systems (serving ≤ 10,000 people)

Large Systems (serving 10,001 - 100,000 people)

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems

Source Water Type Total # of 

Samples

Samples with Detections Samples with Detections 

> 1⁄2 HRL (0.001 μg/L)

Large Systems (serving 10,001 - 100,000 people)

Very Large Systems (serving > 100,000 people) -- CENSUS

All Systems

Samples with Detections 

> HRL (0.002 μg/L)
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 72 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

3 14,572 48 196,970

(1.25%) (2.21%) (1.25%) (2.21%)

3 14,572 48 196,970

(0.63%) (1.21%) (0.08%) (0.42%)

0 0 0 0

(0%) (0%) (0%) (0%)

6 188,603 48 1,128,251

(3.55%) (2.53%) (3.55%) (2.53%)

6 188,603 48 1,128,251

(1.88%) (1.34%) (1.69%) (1.35%)

1 148,137 1 148,137

(1.59%) (0.86%) (1.59%) (0.86%)

11 7,080,239 11 7,080,239

(3.28%) (5.68%) (3.28%) (5.68%)

12 7,228,376 12 7,228,376

(3.02%) (5.09%) (3.02%) (5.09%)

21 7,431,551 109 8,553,597

(1.75%) (4.73%) (0.17%) (3.14%)

Table D25c. NPYR National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 – Summary of System and 

Population Served Data -- All Detections 

141,981,684

All Water Systems 1,198 157,219,620 64,954 272,002,430

All Very Large Systems 398 141,981,684 398

Ground Water 63 17,269,919 63 17,269,919

Surface Water 335 124,711,765 335 124,711,765

All Large Systems 320 14,029,015 2,872 83,406,444

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 151 6,584,184 1,506 38,870,272

Surface Water 169 7,444,830 1,366 44,536,172

All Small Systems 480 1,208,921 61,684 46,614,302

Large Systems (serving 10,001 - 100,000 people)

National Estimate1 of the 

Number (and Percent) of 

Detections

Small Systems (serving ≤ 10,000 people)

37,685,557

Surface Water 240 660,557 3,866 8,928,745

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections in the UCMR 2 

Sample

National Inventory

Ground Water 240 548,364 57,818

1 National estimates for the small and large systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages 

and national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems 

are based directly on the UCMR 2 results, since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey Monitoring. Due 

to rounding, some calculations may appear to be slightly off.

All Systems
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 73 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

3 14,572 48 196,970

(1.25%) (2.21%) (1.25%) (2.21%)

3 14,572 48 196,970

(0.63%) (1.21%) (0.08%) (0.42%)

0 0 0 0

(0%) (0%) (0%) (0%)

6 188,603 48 1,128,251

(3.55%) (2.53%) (3.55%) (2.53%)

6 188,603 48 1,128,251

(1.88%) (1.34%) (1.69%) (1.35%)

1 148,137 1 148,137

(1.59%) (0.86%) (1.59%) (0.86%)

11 7,080,239 11 7,080,239

(3.28%) (5.68%) (3.28%) (5.68%)

12 7,228,376 12 7,228,376

(3.02%) (5.09%) (3.02%) (5.09%)

21 7,431,551 109 8,553,597

(1.75%) (4.73%) (0.17%) (3.14%)

Table D25d. NPYR National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 – Summary of System and 

Population Served Data -- Detections > 1/2 HRL 

All Systems

All Water Systems 1,198 157,219,620 64,954 272,002,430

Surface Water 335 124,711,765 335 124,711,765

All Very Large Systems 398 141,981,684 398 141,981,684

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 63 17,269,919 63 17,269,919

44,536,172

All Large Systems 320 14,029,015 2,872 83,406,444

Surface Water 169 7,444,830 1,366

Large Systems (serving 10,001 - 100,000 people)

Ground Water 151 6,584,184 1,506 38,870,272

Surface Water 240 660,557 3,866 8,928,745

All Small Systems 480 1,208,921 61,684 46,614,302

National Inventory

National Estimate1 of the 

Number (and Percent) of 

Detections > 1/2 HRL (0.001 

μg/L)

Ground Water 240 548,364 57,818 37,685,557

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections > 1/2 HRL (0.001 

μg/L) in the UCMR 2 Sample

1 National estimates for the small and large systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages 

and national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems 

are based directly on the UCMR 2 results, since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey Monitoring. Due 

to rounding, some calculations may appear to be slightly off.

Small Systems (serving ≤ 10,000 people)
EPA-OGWDW

Appendix D. July 2011 UCMR 2 Data: Summary of Occurrence Based on Samples, Systems, and Population Served

Occurrence Data from the UCMR 2 - DRAFT April 2014

Page 74 of 74

Systems Population Systems Population Systems Population Systems Population

0 0 0 0

(0%) (0%) (0%) (0%)

3 14,572 48 196,970

(1.25%) (2.21%) (1.25%) (2.21%)

3 14,572 48 196,970

(0.63%) (1.21%) (0.08%) (0.42%)

0 0 0 0

(0%) (0%) (0%) (0%)

6 188,603 48 1,128,251

(3.55%) (2.53%) (3.55%) (2.53%)

6 188,603 48 1,128,251

(1.88%) (1.34%) (1.69%) (1.35%)

1 148,137 1 148,137

(1.59%) (0.86%) (1.59%) (0.86%)

11 7,080,239 11 7,080,239

(3.28%) (5.68%) (3.28%) (5.68%)

12 7,228,376 12 7,228,376

(3.02%) (5.09%) (3.02%) (5.09%)

21 7,431,551 109 8,553,597

(1.75%) (4.73%) (0.17%) (3.14%) All Water Systems 1,198 157,219,620 64,954 272,002,430

All Very Large Systems 398 141,981,684 398 141,981,684

All Systems

Ground Water 63 17,269,919 63 17,269,919

Surface Water 335 124,711,765 335 124,711,765

All Large Systems 320 14,029,015 2,872 83,406,444

Very Large Systems (serving > 100,000 people) -- CENSUS

Ground Water 151 6,584,184 1,506 38,870,272

Surface Water 169 7,444,830 1,366 44,536,172

All Small Systems 480 1,208,921 61,684 46,614,302

Large Systems (serving 10,001 - 100,000 people)

Ground Water 240 548,364 57,818 37,685,557

Surface Water 240 660,557 3,866 8,928,745

Source Water Type UCMR 2 Sample

Number (and Percent) of 

Detections > HRL (0.002 μg/L) 

in the UCMR 2 Sample

National Inventory

National Estimate1

 of the 

Number (and Percent) of 

Detections > HRL (0.002 

μg/L)

Small Systems (serving ≤ 10,000 people)

1 National estimates for the small and large systems are generated by multiplying the UCMR 2 national statistical sample findings of system/population percentages 

and national system/population inventory numbers for PWSs developed from EPA’s SDWIS, the CWSS, and UCMR. National estimates for the very large systems 

are based directly on the UCMR 2 results, since this was a census, i.e., all very large systems were required to conduct UCMR 2 Screening Survey Monitoring. Due 

to rounding, some calculations may appear to be slightly off.

Table D25e. NPYR National Occurrence Measures Based on UCMR 2 Screening Survey Data thru July 2011 – Summary of System and 

Population Served Data -- Detections > HRL