U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2005–5059

Prepared in cooperation with the Indiana Department of Environmental Management

Methods Used to Assess the Susceptibility to 

Contamination of Transient, Non-Community 

Public Ground-Water Supplies in Indiana 

38

39

40

41

88 87 86 85

10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

0

Base from U.S. Geological Survey digital data 

1:100,000, 1983. Universal Transverse Mercator 

projection, Zone 16, North American Datum 1983

EXPLANATION

Location of a transient, 

non-community 

public-water supply

Methods Used to Assess the 

Susceptibility to Contamination of 

Transient, Non-Community Public 

Ground-Water Supplies in Indiana 

By Leslie D. Arihood and David A. Cohen

Prepared in cooperation with the

Indiana Department of Environmental Management

Scientific Investigations Report 2005–5059

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

DIRK KEMPTHORNE, Secretary

U.S. Geological Survey

Mark D. Myers, Director

U.S. Geological Survey, Reston, Virginia: 2007

For product and ordering information:

World Wide Web: http://www.usgs.gov/pubprod

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U.S. Government.

Although this report is in the public domain, permission must be secured from the individual copyright owners to 

reproduce any copyrighted materials contained within this report.

Suggested citation:

Arihood, L.D., and Cohen, D.A., 2007, Methods used to assess the susceptibility to contamination of transient, noncommunity public ground-water supplies in Indiana: U.S. Geological Survey Scientific Investigations Report 2005-

5059, 39 p.
iii

Contents

Abstract...........................................................................................................................................................1

Introduction.....................................................................................................................................................2

Indiana’s Source-Water Assessment Plan.......................................................................................2

Purpose and Scope ..............................................................................................................................4

Methods Used to Assess the Susceptibility to Contamination ..............................................................4

Methods Used to Qualitatively Describe Susceptibility.................................................................4

Presence of Potential Sources and Associated Contaminants of Concern ......................4

Hydrogeologic and Geomorphic Descriptions........................................................................5

Methods Used to Determine a Susceptibility Rating....................................................................12

Summary........................................................................................................................................................18

References Cited..........................................................................................................................................20

Appendixes 1–3............................................................................................................................................23

1. Example Transient, Non-Community Source-Water Assessment Report.....................24

2. Potential Sources of Drinking-Water Contamination Index ............................................32

3. Concentrations of Nitrate and Thickness of Fine-Grained Geologic

Materials Above the Well Screen in Indiana.....................................................................39

Figures

1–3. Maps showing:

1. Transient, non-community public-water supplies in Indiana ....................................3

2. Location and extent of unconsolidated regional aquifers in Indiana.....................10

3. Location and extent of consolidated regional aquifers in Indiana..........................11

4–5. Graphs showing:

4. Relation between concentrations of nitrate as nitrogen in 

 ground water and the thickness of fine-grained geologic materials 

 above the well screen in Indiana ...................................................................................15

5. Probability of nitrate as nitrogen in ground water being greater than 

 or equal to 3 milligrams per liter for various thicknesses of fine-grained 

 geologic materials above the well screen in Indiana ................................................16

6. Flow chart showing the process for determining the susceptibility rating of 

transient, non-community ground-water supplies in Indiana.............................................17

7. Graph showing intervals in which thickness of fine-grained geologic materials 

is considered thin, moderate, and thick..................................................................................19
iv

Tables

1. Electronic data sets for identifying potential point sources of 

contamination outside the assessment area for a transient, non-community 

public-water supply......................................................................................................................6

2. Classification, by texture, of surficial geologic materials in Indiana...................................9

3. Classification of nitrate source based upon range of concentration in 

ground water...............................................................................................................................10

4. U.S. Geological Survey National Water Information System lithologies and 

texture category for use in estimating thickness of fine-grained geologic 

materials above a well screen .................................................................................................14

5. Statistical characteristics of the logistic regression............................................................16
v

Conversion Factors, Abbreviations, and Datums

Multiply By To obtain

Length

foot (ft) 0.3048 meter (m)

meter (m) 3.281 foot (ft) 

mile (mi) 1.609 kilometer (km)

meter (m) 3.281 foot (ft) 

Mass

kilogram (kg) 2.2046 pounds (lb)

Chemical concentrations and water temperature are given in metric units in milligrams per liter 

(mg/L). A milligram per liter is a unit expressing the concentration of chemical constituents in 

solution as weight (milligrams) of solute per unit volume (liter) of water. 

Abbreviations

COC — Contaminant of concern

COCs —Contaminants of concern

DEM — Digital elevation model

GIS — Geographic information system

IDEM — Indiana Department of Environmental Management

IDNR — Indiana Department of Natural Resources

N — Nitrogen

NWIS — National Water Information System

PCS — Permit Compliance System

SIC — Standard Industrial Classification

SWA — Source-water assessment

SWAP — Source-Water Assessment Plan

TNC — Transient, non-community

TRI — Toxics Release Inventory 

USEPA — U.S. Environmental Protection Agency 

USGS — U.S. Geological Survey

Vertical coordinate information is referenced to the North American Vertical Datum of 1988 

(NAVD 88).

Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83).

Altitude, as used in this report, refers to distance above the vertical datum. 
vi
Methods Used to Assess the Susceptibility to 

Contamination of Transient, Non-Community

Public Ground-Water Supplies in Indiana

By Leslie D. Arihood and David A. Cohen

Abstract

The Safe Water Drinking Act of 1974 as amended in 

1996 gave each State the responsibility of developing a 

Source-Water Assessment Plan (SWAP) that is designed to 

protect public-water supplies from contamination. Each SWAP 

must include three elements: (1) a delineation of the sourcewater protection area, (2) an inventory of potential sources 

of contaminants within the area, and (3) a determination of 

the susceptibility of the public-water supply to contamination from the inventoried sources. The Indiana Department 

of Environmental Management (IDEM) was responsible for 

preparing a SWAP for all public-water supplies in Indiana, 

including about 2,400 small public ground-water supplies that 

are designated transient, non-community (TNC) supplies. In 

cooperation with IDEM, the U.S. Geological Survey compiled 

information on conditions near the TNC supplies and helped 

IDEM complete source-water assessments for each TNC 

supply.

The delineation of a source-water protection area (called 

the assessment area) for each TNC ground-water supply was 

defined by IDEM as a circular area enclosed by a 300-foot 

radius centered at the TNC supply well. Contaminants of concern (COCs) were defined by IDEM as any of the 90 contaminants for which the U.S. Environmental Protection Agency has 

established primary drinking-water standards. Two of these, 

nitrate as nitrogen and total coliform bacteria, are Indiana 

State-regulated contaminants for TNC water supplies. IDEM 

representatives identified potential point and nonpoint sources 

of COCs within the assessment area, and computer database 

retrievals were used to identify potential point sources of 

COCs in the area outside the assessment area.

Two types of methods—subjective and subjective 

hybrid—were used in the SWAP to determine susceptibility 

to contamination. Subjective methods involve decisions based 

upon professional judgment, prior experience, and (or) the 

application of a fundamental understanding of processes without the collection and analysis of data for a specific condition. 

Subjective hybrid methods combine subjective methods with 

quantitative hydrologic analyses.

The subjective methods included an inventory of potential sources and associated contaminants, and a qualitative 

description of the inherent susceptibility of the area around the 

TNC supply. The description relies on a classification of the 

hydrogeologic and geomorphic characteristics of the general 

area around the TNC supply in terms of its surficial geology, 

regional aquifer system, the occurrence of fine- and coarsegrained geologic materials above the screen of the TNC well, 

and the potential for infiltration of contaminants. The subjective hybrid method combined the results of a logistic regression analysis with a subjective analysis of susceptibility and a 

subjective set of definitions that classify the thickness of finegrained geologic materials above the screen of a TNC well in 

terms of impedance to vertical flow. The logistic regression 

determined the probability of elevated concentrations of nitrate 

as nitrogen (greater than or equal to 3 milligrams per liter) in 

ground water associated with specific thicknesses of finegrained geologic materials above the screen of a TNC well. In 

this report, fine-grained geologic materials are referred to as a 

geologic barrier that generally impedes vertical flow through 

an aquifer. A geologic barrier was defined to be thin for finegrained materials between 0 and 45 feet thick, moderate for 

materials between 45 and 75 feet thick, and thick if the finegrained materials were greater than 75 feet thick.

A flow chart was used to determine the susceptibility rating for each TNC supply. The flow chart indicated a susceptibility rating using (1) concentrations of nitrate as nitrogen 

and total coliform bacteria reported from routine compliance 

monitoring of the TNC supply, (2) the presence or absence of 

potential sources of regulated contaminants (nitrate as nitrogen and coliform bacteria) within the assessment area, and 

(3) the thickness of the geologic barrier above the TNC well 

screen. The possible susceptibility ratings were: “currently 

not susceptible,” “moderately susceptible,” or “susceptible,” A 

rating of susceptible was automatically given to a TNC supply 

if there was a detection of coliform bacteria or a concentration of nitrate as nitrogen greater than 3 mg/L in any compliance-monitoring sample. Less than 2 percent (43) of the TNC 

supplies could not be rated because they were new and no 

compliance-monitoring data were available. Only one of the 
2 Methods Used to Assess the Susceptibility to Contamination of Transient, Non-Community Public Ground-Water Supplies

TNC supplies was rated not currently susceptible, approximately 7 percent (164) were rated moderately susceptible, and 

approximately 91 percent (2,144) were rated susceptible. Of 

the 2,144 TNC supplies rated susceptible, approximately 

79 percent (1,694) had a detection of coliform bacteria or a 

concentration of nitrate as nitrogen greater than 3 mg/L in at 

least one compliance-monitoring sample.

Introduction

Amendments made in 1996 to the Safe Drinking Water 

Act of 1974 required a Source-Water Assessment Plan 

(SWAP) to be developed by each State under the direction of 

the U.S. Environmental Protection Agency (USEPA) (U.S. 

Environmental Protection Agency, 1997, p. 2-1). A SWAP is 

designed to protect public-water supplies from contamination. 

A SWAP must include three elements: (1) a delineation of 

the source-water protection area, (2) an inventory of potential 

sources of contaminants within the area, and (3) a determination of the susceptibility of the public-water supply to the 

sources inventoried (U.S. Environmental Protection Agency, 

1997, p. 2-12). The inventory of potential sources identifies 

sites that may release any of the 90 contaminants for which 

the USEPA has established primary drinking-water standards 

(Indiana Department of Environmental Management, 2000, 

Appendix E; U.S. Environmental Protection Agency, 2002). 

In the remainder of this report, these 90 contaminants will be 

referred to as the “contaminants of concern” (COCs), with a 

single contaminant of concern abbreviated as “COC.” Under 

the guidelines of Indiana’s SWAP, a source-water assessment 

(SWA) must be prepared for all large and small public-water 

supplies that use surface water and (or) ground water as their 

source. The Indiana Department of Environmental Management (IDEM) is responsible for administering the SWAP for 

Indiana. Part of their responsibility is to explain the methods 

used to accomplish the goals of each element of the SWAP.

Indiana’s Source-Water Assessment Plan

The U.S. Geological Survey (USGS), in cooperation with 

the IDEM, compiled data and provided technical assistance 

in the preparation of SWAs for the small public ground-water 

supplies designated as transient, non-community (TNC) supplies. TNC supplies include facilities using low pump-rate 

ground-water supplies and serving people who remain at 

the facility for short periods. Examples of TNC supplies are 

motels, gasoline stations, churches, golf-course clubhouses, 

and restaurants. As of 1999, there were approximately 2,400 

such facilities in Indiana (Indiana Department of Environmental Management, 2000, p. 31) (fig. 1). A school would not be 

classified as a TNC supply because the public (students and 

staff) remain at the facility all day for many days in any given 

year.

The IDEM’s approach to the preparation of a SWA for 

TNC supplies is based upon the three elements required by 

USEPA in a SWAP. The delineation of a source-water-protection area (hereinafter referred to as assessment area) was 

defined by IDEM to be the circular area within a 300-ft radius 

centered at the TNC supply well (Indiana Department of Environmental Management, 2000, p. 31). A potential source of 

COCs was defined by IDEM as an activity, facility, location, 

or land use associated with the handling, usage, storage, or 

generation of any COCs (Indiana Department of Environmental Management, 2000, p. 20, 24, 27). The potential sources of 

COCs generally were classified as either point sources (aboveground storage tanks, dry cleaning stores, utility substations) 

or nonpoint sources (agricultural cropland, camp grounds, golf 

courses).

Susceptibility has been defined by IDEM as the potential for a public-water system to draw water contaminated 

by inventoried sources of COCs that would pose concern for 

water operators or consumers (Indiana Department of Environmental Management, 2000, p. 19). The IDEM requested 

that the analysis of susceptibility for a TNC supply include 

consideration of several conditions present in the assessment area, such as (1) land use; (2) the presence or absence 

of low-permeability geologic materials; (3) general aquifer 

characteristics, including ground-water flow direction; and 

(4) presence and proximity of potential sources of COCs to 

the well, with particular emphasis on potential sources of 

nitrate as nitrogen and coliform bacteria, which are the only 

COCs that are regulated for TNC supplies in Indiana (Indiana 

Department of Environmental Management, 2000, p. 19, 31; 

Indiana Administrative Code, 2006), and are hereafter referred 

to as “regulated COCs” in this report. These conditions were 

assessed and used by the USGS in a susceptibility analysis for 

the TNC supplies.

In cooperation with the IDEM, the USGS compiled information about conditions near the TNC supplies to perform a 

susceptibility analysis for the nearly 2,400 TNC supplies in 

Indiana. The information consisted of a compilation of potential sources and associated regulated COCs, land use, surficial 

and subsurface geologic materials, regional aquifer descriptions, land slope, and ground-water level data. The information 

was used with qualitative and quantitative methods to assess 

the susceptibility of each TNC supply to contamination and 

to prepare 2-page reports for distribution by the IDEM to the 

general public.
Figure 1. Transient, non-community public-water supplies in Indiana.

38

39

40

41

88 87 86 85

10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

0

Base from U.S. Geological Survey digital data 1:100,000. 1983

Universal Transverse Mercator projection, Zone 16, North American Datum 1983

EXPLANATION

Location of a transient,

non-community publicwater supply

Introduction 3
4 Methods Used to Assess the Susceptibility to Contamination of Transient, Non-Community Public Ground-Water Supplies

Purpose and Scope

This report describes the details of the methods and 

terminology used by the IDEM and the USGS to complete a 

susceptibility analysis for about 2,400 TNC ground-water supplies. The report includes details of methods used to provide 

general, qualitative assessments of susceptibility as well as 

methods used to obtain a specific susceptibility rating. The 

report distinguishes the methods according to their use of professional judgment and quantitative hydrologic analysis.

Methods Used to Assess the 

Susceptibility to Contamination

Some methods were used to describe susceptibility of 

TNC supplies qualitatively without specifying a degree of 

susceptibility, and other methods were used to classify susceptibility into one of three susceptibility ratings. The qualitative 

description of susceptibility used subjective methods, and the 

rating of susceptibility used both subjective and subjective 

hybrid methods.

Subjective methods are those in which professional judgment is used to delineate assessment areas, classify conditions, 

and analyze susceptibility. For example, the assessment area 

for a TNC supply was subjectively chosen by the IDEM as 

a fixed radius of 300 ft around the well. The IDEM considers this area sufficiently large to include the area contributing water to the well in most cases, given what generally is 

known about ground-water travel times in Indiana (Indiana 

Department of Environmental Management, 2000, p. 28, 31). 

The term “subjective” should not infer a concept of inferior 

or potentially incorrect analysis. Subjective methods involve 

decisions that are made on the basis of prior experience and 

(or) application of a fundamental understanding of processes 

without the collection and analysis of data for a specific 

condition (Focazio and others, 2002). The SWAP could not be 

completed without subjective decisions.

Subjective hybrid methods combine subjective methods 

with quantitative hydrologic analyses. For example, a logistic 

regression analysis was used to quantify a relation between 

the concentration of nitrate as nitrogen in ground water and 

the thickness of fine-grained geologic materials above a well 

screen. Interpretations based upon this quantitative relation, 

in combination with qualitative information, were used to 

subjectively assign each TNC supply to one of three susceptibility ratings. Focazio and others (2002) provide additional 

details regarding the definition and use of subjective and 

subjective hybrid methods in assessing ground-water susceptibility to contamination. An example of the application of these 

methods to a specific site is provided in Appendix 1, which 

contains the source-water-assessment report for a gasoline 

service station in Marion County, Indiana.

Methods Used to Qualitatively Describe 

Susceptibility

Two subjective methods were used to qualitatively 

describe susceptibility to contamination for the TNC groundwater supplies. The first method determined the presence of 

potential sources of contaminants in and around the assessment area and identified COCs that may be associated with 

each of these sources. The second subjective method provided 

a description of susceptibility based upon hydrogeologic and 

geomorphic characteristics in the general area of the TNC 

supply.

Presence of Potential Sources and Associated 

Contaminants of Concern

During on-site visits to each TNC supply, IDEM representatives identified potential point and nonpoint sources of 

COCs within the assessment area. Point sources were located 

using mapping-grade global positioning equipment, and nonpoint sources were visually estimated as a percentage of the 

assessment area. The relation between potential contaminant 

sources in the assessment area and specific COCs was based 

upon a reference prepared by the USEPA called “Potential 

Sources of Drinking-Water Contamination Index” (U.S. 

Environmental Protection Agency, 2004, Appendix 2) that lists 

potential contaminant sources and associated COCs .

Potential point sources outside the assessment area, but 

within the area of the figures in the SWA reports for the TNC 

supplies, were identified by a geographic-information-system 

(GIS) retrieval from 22 computerized databases (table 1).

Many of the records in these databases contained a 

Standard Industrial Classification (SIC) code that describes the 

type of facility or activity associated with the potential point 

source (Office of Management and Budget, 1987). Identification of associated COCs with these potential sources was 

based upon information obtained from the Toxics Release 

Inventory (TRI) (U.S. Environmental Protection Agency, 

1999) and the Permit Compliance System (PCS) (Joe Lewis, 

Data Management Branch, U.S. Environmental Protection 

Agency, written commun., October 26, 1999) databases. The 

TRI and PCS databases include records that identify a SIC 

code representing a type of facility or activity and COCs that 

are associated with that type of facility or activity. Records 

from both databases were combined to form a table (the TRIPCS table) that relates SIC codes to associated COCs. For 

records of potential point sources outside an assessment area 

that contained a SIC code, the TRI-PCS table was used to 

identify associated COCs.

For records of potential point sources outside the assessment area that did not have a SIC code, an attempt was made 

to use the available computerized information in those records 

to match an appropriate category in the USEPA reference 
“Potential Sources of Drinking-Water Contamination Index” 

(U.S. Environmental Protection Agency, 2004, Appendix 2)

to identify associated COCs. For example, if the computerized 

record for a potential point source outside the assessment area 

lacked a SIC code, but had the name “XYZ Gas Station #63,” 

then this potential point source would be associated with the 

COCs listed for the category “Gas Stations” in the Appendix 2 

reference. There were some identified potential point sources 

outside the assessment area that could not be associated with 

any COCs, either because their SIC codes were not associated with any COCs in the TRI-PCS table, or, if the computer 

record did not contain a SIC code, the remaining computerized 

information was insufficient to allow a matching category to 

be identified in the USEPA reference.

All potential point sources were included in a table 

associated with the SWA report for the TNC supply (Appendix 

1). The table included the following information: name and 

type of potential point source; location method; data source, 

either from an on-site visit inside the assessment area or from 

a computer database retrieval outside the assessment area; 

associated regulated COCs; and all associated COCs. Potential 

nonpoint sources, their respective estimated percentage of the 

assessment area, associated regulated COCs, and all associated 

COCs, were included in a second table associated with the 

SWA report for the TNC supply (Appendix 1).

The COCs listed in the tables may not always be present 

at a given potential source, and the list of contaminants may 

not include all contaminants that could be present. Both tables 

were accessed via a hyperlink in the SWA report. Additionally, all potential point sources of contamination were plotted 

on figure 2 of the SWA report for the TNC supply (Appendix 

1). A larger number of potential sources of COCs can indicate 

a greater susceptibility of the water supply to contaminant 

releases. The information regarding the presence of potential 

sources of regulated COCs was used as a factor in the subjective hybrid method described in the section “Methods Used to 

Determine a Susceptibility Rating.”

Hydrogeologic and Geomorphic Descriptions

The second subjective method used in the SWAP was a 

qualitative description of the inherent susceptibility to contamination of the general area around the TNC supply. The 

description was not meant to provide a specific susceptibility 

rating for a TNC supply, but to provide additional information about general susceptibility. The qualitative description 

relied on hydrogeologic and geomorphic characteristics of the 

assessment and surrounding area. For example, if an area is 

underlain by thick clays, the vertical movement of contaminants is restricted by the low hydraulic conductivity typically 

associated with the fine-grained materials contained in the clay 

(Freeze and Cherry, 1979, p. 29). The presence of fine-grained 

geologic materials above an aquifer is considered by IDEM 

to provide some degree of protection from contamination by 

surface contaminants—the thicker the fine-grained materials 

the greater the degree of protection (Indiana Department of 

Environmental Management, 2000, p. 18-19). Five hydrogeologic and geomorphic characteristics were used to qualitatively 

describe the susceptibility of the assessment area: typical geologic materials above the TNC well screen, surficial geology, 

regional aquifer system, land slope, and ground-water flow 

direction (Appendix 1). The following paragraphs explain the 

susceptibility interpretations based on these characteristics and 

present the text used in the SWA reports for the TNC supplies. 

The order of presentation of the material parallels the order 

used in the TNC reports.

The geologic materials above the TNC well screen are 

the most influential in determining the well’s inherent sensitivity to surface contaminants. Fine-grained geologic materials, 

which IDEM generally refers to as a low-permeability clay 

layer or an aquitard (Indiana Department of Environmental 

Management, 2000, p. 19), provide the most protection from 

surface contaminants. A list of the most typical geologic materials above the TNC well screen were determined by an analysis of drillers’ logs of local water wells from the computerized 

well-log database maintained by the Indiana Department of 

Natural Resources (IDNR) (Indiana Department of Natural 

Resources, 2006). The water-well logs provide a description 

of the occurrence and thickness of geologic materials that the 

driller encountered as each well was being drilled. The well 

logs within a 2-mi radius of the TNC supply well were compiled to determine the geologic materials typically encountered and the thickness of each type of material. A file listing 

unique geologic materials and the total thickness of each was 

generated that represents the most typical geologic materials 

between the land surface and the bottom of the TNC well. The 

file was sorted by thickness, and the geologic materials having the three greatest thicknesses were provided in the TNC 

report. For example, the three most abundant lithologies above 

the TNC well screen described in Appendix 1 are clay, gravel, 

and shale. Determining the most abundant geologic materials 

above the TNC well screen is dependent upon the depth of the 

TNC well, which was not always known. Well depths for TNC 

wells with unknown depths were estimated using a conservative method that should underestimate the actual well depth for 

a given TNC well. The following method was used to estimate 

a well depth:

1. Records of domestic water wells within a 5-mi radius 

of the TNC supply were selected. Records of industrial, 

irrigation, or other high-capacity wells within that radius 

were not included in the selection because they were 

expected to be deeper than a typical TNC well. If there 

were fewer than 100 well records in the 5-mi radius, 

the radius was expanded until at least 100 records were 

selected. 

2. The selected well records were sorted by the depth of 

each well.

Methods Used to Assess the Susceptibility to Contamination 5
6 Methods Used to Assess the Susceptibility to Contamination of Transient, Non-Community Public Ground-Water Supplies

Table 1. Electronic data sets for identifying potential point sources of contamination outside the assessment area for a transient, 

non-community public-water supply.—Continued

[USEPA, U.S. Environmental Protection Agency; IDEM–OLQ, Indiana Department of Environmental Management–Office of Land Quality; IAC, Indiana 

Administrative Code; IC, Indiana Code; UST, underground storage tank; IDEM–OWQ, Indiana Department of Environmental Management–Office of Water 

Quality; NPL, National Priorities List; RCRA, Resource Conservation and Recovery Act; IGS, Indiana Geological Survey; USEPA–BASINS, U.S. Environmental Protection Agency–Better Assessment Science Integrating Point and Nonpoint Sources]

Data set name/description Data source1 Description of potential point sources of contamination included in data set

Envirofacts Data for Indiana USEPAEnvirofactsCompilation of information on USEPA regulated facilities.

Inventory of Transfer Stations in 

Indiana

IDEM–OLQ Transfer Stations — transfer of solid waste from one collection vehicle to another 

that later is disposed at a State-approved solid-waste permitted facility, as defined 

by 329 IAC 11-2-47.

Inventory of Composting Facilities 

in Indiana

IDEM–OLQ Composting Facilities — leaf-, limb-, or grass-collection sites where a compost 

product is created, as defined by IC 13-20-10.

Inventory of Confined Feeding 

Operations in Indiana

IDEM–OLQ Confined Feeding Operations — a swine, chicken, turkey, beef, or dairy agribusiness that has large enough numbers of animals that IDEM regulates for 

environmental concerns, as defined by IC 13-18-10.

Inventory of USTs in Indiana IDEM–OLQ USTs — the UST program is responsible for registering all regulated USTs. 

Regulated USTs are those USTs that have 10 percent or more of the tank and 

piping buried beneath the ground and contain a regulated substance, which 

includes either petroleum products or hazardous substances.

Inventory of Leaking USTs in 

Indiana

IDEM–OLQ Leaking USTs — known sites with leaking USTs. Regulated USTs contain 

regulated substances including petroleum and hazardous substances such as those 

typically found at gasoline stations, fleet-fueling facilities, and industrial sites.

Inventory of Construction/

Demolition Sites in Indiana

IDEM–OLQ Construction/Demolition Sites — a permitted State-licensed facility that accepts 

solid waste in the form of anything that is attached to a house during construction 

or demolition, as defined by IAC 329 10-2-36.

Inventory of Open Dumps in Indiana IDEM–OLQ Open Dumps — Sites that are not regulated and are illegal dump sites of solid 

waste, as defined by IAC 10-2-28 329 and IAC 10-2-128.

National Pollutant Discharge 

Elimination System Facilities 

in Indiana

IDEM–OWQ National Pollutant Discharge Elimination System Facilities — all available 

records listed in Indiana associated with “Active” surface-water discharges from 

regulated wastewater-discharge sites. It consists of State-permitted wastewaterfacility-related information.

National Pollutant Discharge 

Elimination System Pipes 

in Indiana

IDEM–OWQ National Pollutant Discharge Elimination System Pipes — includes all “active” 

records listed in Indiana associated with permitted surface-water discharge points. 

It consists of regulated wastewater outfall or end-of-pipe related information 

that originated from sites/facilities in the data set “National Pollutant Discharge 

Elimination System Facilities”

Inventory of Septage Sites in Indiana IDEM–OLQ Septage Sites — permitted septage (septic-tank waste) sites where the waste is land 

applied, as defined by 327 IAC 7, 327 IAC 7-6, and 327 IAC 7-7.

Inventory of Tire Sites in Indiana IDEM–OLQ Tire Sites — sites which contain tires—either for processing, storage, or transport—

as well as some illegal tire dumps, as defined by IC 13-11-2-251, IC 13-11-2-

252, and IC 13-11-250.5.

Inventory of Superfund Sites in 

Indiana

IDEM–OLQ Superfund Sites — USEPA evaluates and prioritizes these sites for placement on the 

NPL as “Superfund Sites” eligible for extensive, long-term cleanup action under 

the Superfund Program.

Inventory of Treatment, Storage, and 

Disposal Sites in Indiana

IDEM–OLQ Treatment, Storage, and Disposal Sites — facilities that may treat, store, generate 

and (or) dispose of hazardous waste, non-hazardous industrial waste, and solid 

waste. 
Table 1. Electronic data sets for identifying potential point sources of contamination outside the assessment area for a transient, 

non-community public-water supply.—Continued

[USEPA, U.S. Environmental Protection Agency; IDEM–OLQ, Indiana Department of Environmental Management–Office of Land Quality; IAC, Indiana 

Administrative Code; IC, Indiana Code; UST, underground storage tank; IDEM–OWQ, Indiana Department of Environmental Management–Office of Water 

Quality; NPL, National Priorities List; RCRA, Resource Conservation and Recovery Act; IGS, Indiana Geological Survey; USEPA–BASINS, U.S. Environmental Protection Agency–Better Assessment Science Integrating Point and Nonpoint Sources]

Data set name/description Data source1 Description of potential point sources of contamination included in data set

Inventory of Voluntary Remediation 

Sites in Indiana

IDEM–OLQ Voluntary Remediation Sites — sites where a voluntary cleanup of hazardous and 

petroleum wastes is conducted with IDEM oversight, and at the conclusion of 

the cleanup a Certificate of Completion from IDEM and a Covenant Not To Sue 

from the Governor’s office is awarded. The Covenant Not To Sue is a release 

of liability that bars enforcement action from the State and third party law suits 

relating to the cleanup. The covenant runs with the land so all subsequent owners 

of the property also receive liability protection.

Inventory of Restricted Waste Sites 

in Indiana

IDEM–OLQ Restricted Waste Sites — sites that accept only specific types of solid waste that fall 

into three select categories, as defined by IAC 329 10-2-159.

Inventory of State Cleanup Sites in 

Indiana

IDEM–OLQ State Cleanup Sites — sites currently administered under the State Cleanup Section. 

Similar to the Federal Superfund Program, these abandoned or uncontrolled 

hazardous-waste sites in Indiana are evaluated for extensive, long-term cleanup 

action. 

Inventory of Industrial-Waste Sites 

in Indiana

IDEM–OLQ Industrial-Waste Sites — facilities that generate and (or) manage hazardous waste, 

non-hazardous industrial waste, and solid waste. The majority are Large Quantity 

Generators (facilities that generate more than 1,000 kilograms—about 2,200 

lbs.—of hazardous waste per month). Treatment, Storage, and Disposal facilities 

that may treat, store, generate and (or) dispose hazardous waste, non-hazardous 

industrial waste, and solid waste. Small Quantity Generators (facilities that 

generate less than 1,000 kilograms—about 2,200 lbs. —but more than 100 

kilograms—about 220 lbs. —of hazardous waste per month), or Conditionally 

Exempt Small Quantity Generators (facilities that generates less than 100 

kilograms—about 220 lbs. —of hazardous waste per month) are included if the 

location has significant environmental issues.

Inventory of Active Permitted SolidWaste SitesIDEM–OLQ Active Permitted Solid-Waste Sites — sites that have received a solid-waste-facility 

permit issued under either 329 IAC 10 (land-disposal facilities) or 329 IAC 11 

(processing facilities), have finished construction, and are actively receiving 

waste.

Inventory of Corrective-Action Sites 

in Indiana

IDEM–OLQ Corrective Action Sites — facilities that are subject to RCRA corrective action. 

These are facilities that meet any of the following conditions: operating under 

a hazardous-waste permit, an interim status facility, and lawsuit against any 

handler.

Inventory of Oil and Gas Wells in 

Indiana 

IGS Oil and Gas Wells — producing oil and gas wells; gas-storage wells; and abandoned 

gas, oil, and gas-storage wells.

Inventory of Mines and Quarries in 

Indiana

USEPA–

BASINS

Mines and Quarries — Includes above ground and underground mines or quarries 

and processing facilities for coal, limestone, building stone, sand and gravel, clay, 

gypsum, perlite, and other materials.

1

Data-source references:

USEPA Envirofacts (U.S. Environmental Protection Agency, 2001a)

IDEM-OLQ (Greg Overtoom, Indiana Department of Environmental Management, Office of Land Quality, written commun., June 20, 2002; Shane Moore, 

Indiana Department of Environmental Management, Office of Land Quality, written commun., 2004)

IDEM-OWQ (Jeff Ewick, Indiana Department of Environmental Management, Office of Water Quality, written commun., February 5, 2003)

IGS (Indiana Geological Survey, 2004)

USEPA–BASINS (U.S. Environmental Protection Agency, 2001b)

Methods Used to Assess the Susceptibility to Contamination 7
8 Methods Used to Assess the Susceptibility to Contamination of Transient, Non-Community Public Ground-Water Supplies

3. The estimated depth of the TNC well was chosen such 

that the depths of 75 percent of the selected well records 

were greater than the estimated depth.

The surficial geology at and around a TNC supply well 

can be classified for the purpose of susceptibility by texture. 

The relation between surficial geologic materials and susceptibility was based upon the capability of surface materials 

to limit the infiltration of water into the ground and thereby 

reduce the transport of any associated contaminants. The 

surficial geology of Indiana has been mapped using 49 different geologic classifications (Gray, 1989). The classifications 

are too numerous to use directly in measuring infiltration 

capacity; therefore, the classifications were grouped into 

similar geologic materials. For example, the 14 different tills 

were grouped into a class simply called till. This process was 

repeated until the surficial geologic materials were grouped 

into 5 general texture classifications (table 2). The specific texture groups within the assessment area were determined, and 

text describing the textures was included in the SWA report 

for the TNC supply. The following paragraphs contain the 

text used to describe each texture group and their relation to 

susceptibility. The texture groups in the following paragraphs 

are identified by bold type.

Fine-grained surficial geologic materials, such as clay 

and silt, tend to slow the movement of and provide a filtering action to water entering the ground. Compared to clay or 

silt, coarse-grained surficial geologic materials, such as sand 

and gravel, allow more surface water to infiltrate and provide 

less filtering action to water entering the ground. Mixtures 

of sands and silts have protective properties between clays 

(less infiltration of water and greater filtering of particulates) 

and coarser sands or gravels (more infiltration and less filtering). Fine-grained soils that form on bedrock at the ground 

surface tend to slow the infiltration of, and provide a filtering 

action to, water entering the ground. However, local fractures 

in the upper part of the bedrock, when present at or very close 

to the land surface, can facilitate entry of surface contaminants 

into the ground water. Fine-grained soils also develop on karst

areas, but the overriding factor controlling infiltration in karst

areas is the development of solution channels. Surface water 

and associated contaminants can readily enter the ground in 

karst areas through sinkholes or through thin soils overlaying 

subsurface channels.

The composition of regional aquifers can provide general information about how well the aquifers are protected 

from contamination. Regional aquifers have been defined as 

geologic deposits formed by the same process and containing 

sufficient saturated permeable material to yield quantities of 

potable water adequate at least for domestic purposes (Fenelon 

and others, 1994). An example of a regional aquifer would be 

glacial drift containing discontinuous deposits of sand or sand 

and gravel, herein referred to as the Discontinuous Buried 

Sand and Gravel Regional Aquifers. Regional aquifers have 

been mapped for major Indiana watersheds (Fenelon and 

others, 1994). The complete extents of the unconsolidated 

regional aquifers are shown in figure 2, and the extents of the 

consolidated regional aquifers are shown in figure 3.

The susceptibility of regional aquifers to surface contaminants can be assessed according to their depth from the 

land surface and their areal extent. Generally, the deeper and 

the less aerially extensive the aquifer, the more the aquifer 

is protected from a point source of contaminants. Some of 

the regional aquifers of Indiana have been named to convey 

these two characteristics. The regional aquifers within the 

assessment area for a TNC supply were determined, and text 

describing the aquifers was included in the report for the TNC 

supply. More than one regional aquifer may lie beneath the 

assessment area because regional aquifers can overlap. The 

following paragraphs contain the text used to describe each 

regional aquifer and its susceptibility to surface contaminants. 

The regional aquifers are identified by bold type.

The Surficial Sand and Gravel Regional Aquifers 

consist of sand or sand and gravel that is areally continuous in 

at least one direction for several miles. The aquifer materials 

were deposited by glacial meltwater and present-day stream 

deposition. The aquifers range in thickness from 5 to 175 ft 

and are covered by less than 10 ft of clay, silt, and fine sand. 

The thin layer of fine-grained material over the aquifer makes 

it more vulnerable to contaminant sources than most other 

regional aquifers.

The Discontinuous Surficial Sand and Gravel 

Regional Aquifers consist of sand or sand and gravel that is 

areally continuous for less than 1 mi. The aquifer material was 

deposited as layers of outwash, drift, and till at the edge of 

melting glacial ice. The aquifers range in thickness from 5 to 

100 ft and are covered by less than 10 ft of clay, silt, and fine 

sand. The thin layer of fine-grained deposits over the aquifer 

material makes it more vulnerable to contamination sources 

than most other regional aquifers, although its discontinuous 

nature limits the area in which contaminants would enter the 

aquifer.

Table 2. Classification, by texture, of surficial geologic materials 

in Indiana.

Texture

classification

Associated surficial

geologic materials 

Fine-grained Till; silt complex; terra rosa; overburden 

and artificial fill; lake silt and clay; muck, 

peat, and marl; loess

Coarse-grained Outwash; ice-contact deposits; lake and 

beach sand; dune and blanket sand

Mixtures of 

sands and silts

Alluvium; sand and silt

Fine-grained 

soils formed 

on bedrock

Devonian to Mississippian black shale; 

Mississippian limestone; Silurian and 

Devonian limestone and dolomite; 

siltstone and shale; mixed sandstone, 

shale, limestone, and coal; Ordovician 

shale and limestone

Karst Karst
Methods Used to Assess the Susceptibility to Contamination 9

Figure 2. Location and extent of unconsolidated regional aquifers in Indiana. 

38

39

40

41

88 87 86 85

10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

0

Base from US Geological Survey digital data 1:100,000. 1983

Universal Transverse Mercator projection, Zone 16, NAD 83

EXPLANATION

Surficial sand and

gravel aquifer

Discontinuous surficial

sand and gravel aquifer

Buried sand and gravel

aquifer

Discontinuous buried

sand and gravel aquifer

Area without an

unconsolidated aquifer

Boundary of buried

bedrock valley aquifer

Geology from Fenelon and others, 1994
10 Methods Used to Assess the Susceptibility to Contamination of Transient, Non-Community Public Ground-Water Supplies

Figure 3. Location and extent of consolidated regional aquifers in Indiana.

38

39

40

41

88 87 86 85

10 20 30 40 50 MILES

0 10 20 30 40 50 KILOMETERS

0

Base from US Geological Survey digital data 1:100,000. 1983

Universal Transverse Mercator projection, Zone 16, NAD 83

EXPLANATION

Carbonate bedrock

aquifer

Complexly interbedded

sandstone, shale,

limestone, and coal

aquifer

Sandstone aquifer

Upper weathered

bedrock aquifer

Area without a

consolidated aquifer

Geology from Fenelon and others, 1994
Methods Used to Assess the Susceptibility to Contamination 11

The Buried Sand and Gravel Regional Aquifers

consist of sand or sand and gravel that is areally continuous 

in at least one direction for several miles. The aquifer materials originated from glacial meltwater as either outwash fans 

(aerial deposits) or channel deposits. The aquifers range in 

thickness from 5 to 225 ft and are covered by 10 ft or more of 

clay, silt, and fine sand. The overlying fine-grained materials 

are typically much more than 10 ft in thickness outside the 

river valleys. In the uplands, the aquifer is typically covered by 

tens of feet of low-permeability till, which provides protection 

from point and nonpoint contaminant sources.

The Discontinuous Buried Sand and Gravel Regional 

Aquifers consist of sand or sand and gravel lenses that are 

areally continuous in at least one direction from 1 to 5 mi. The 

aquifer is commonly reported by water-well drillers because 

the lenses of aquifer material may be present at multiple 

depths within the glacial till. The aquifer lenses range in thickness from 5 to 80 ft, and are typically covered by tens of feet 

of fine-grained glacial till. The till provides protection from 

point and nonpoint contaminant sources.

The Buried Bedrock Valley Regional Aquifer consists 

of glacial deposits of sand and gravel that filled the preglacial Teays River valley over multiple glacial periods. The 

aquifer can be as much as 200 ft in thickness and is deeply 

buried beneath glacial till. The thick cover of fine-grained till 

provides considerable protection from contaminant sources at 

ground surface.

The Carbonate Bedrock Regional Aquifer consists of 

limestone and dolomite deposits that underlie over half of the 

State. The upper 100 ft of the formation contains voids from 

weathering and dissolution of rock material along fractures, 

bedding planes, and joints. The voids can provide conduits for 

contaminants to spread through the aquifer. In the northern 

two-thirds of the State, the aquifer is overlain by fine-grained 

glacial till that provides protection from contaminant sources 

at ground surface.

The Sandstone Regional Aquifer consists of sheet or 

channel deposits of cemented sands that extend over several 

miles. The aquifer ranges in thickness from 20 to 250 ft. The 

low permeability of sandstone and the low permeability of 

materials that may overly the sandstone provide protection 

from contaminants at ground surface.

The Complexly Interbedded Sandstone, Shale, Limestone, and Coal Regional Aquifer, as the name implies, is 

a mixture of bedrock deposits. Shale constitutes the majority 

of the unit, but each rock type is limited in areal extent. The 

sandstones, coals, and limestones are typically less than 10 ft 

in thickness, yet they are the most productive part of the aquifer. The water-bearing zones of the aquifer are protected from 

contamination by the large proportion of shale in the aquifer.

The Upper Weathered Bedrock Regional Aquifer

consists of shale and siltstone that developed solution channels 

within the upper 150 ft of bedrock because of the weathering 

process before glaciation. In the northern two-thirds of the 

State, the aquifer is overlain by fine-grained glacial till that 

provides protection from contaminants.

Areas without a consolidated or unconsolidated aquifer have geologic materials that cannot yield sufficient water 

for even domestic purposes. An example is an area of shale of 

Ordovician age in the southeast corner of the State; the shale 

is softer than other shales (Fenelon and others, 1994, p. 191). 

As such, joints and fractures cannot be sustained in this rock. 

Without joints and fractures, usable amounts of water cannot 

be obtained from this shale, and ground-water supplies usually 

are not developed in this area. If supplies were developed, 

then the entry of contaminants into the formation would be 

impeded by the general lack of a pathway (fractures) for the 

contaminant to enter the formation.

The slope of the land surface affects the potential for 

infiltration of contaminated surface waters. Specifically, the 

lower the slope, the lower the potential for surface runoff and 

the greater the potential for infiltration. The Natural Resource 

Conservation Service and the Purdue University Agricultural 

Experiment Station classified land slopes for Indiana into five 

slope ranges: 0–2 percent, 2–6 percent, 6–18 percent, 18–35 

percent, and greater than 35 percent (U.S. Department of 

Agriculture, 1977). They also describe the geomorphic characteristics associated with the slopes in terms of land-surface 

topography. The average slope within the 300-ft radius of the 

TNC supply was determined using a 30-m digital elevation 

model (DEM) (U.S. Geological Survey, 2000), and the slope 

was assigned to a slope range. Text describing the slope range 

was included in the SWA report for each TNC supply. The 

following list contains the text used in the reports to describe 

each slope range and its relation to susceptibility; the slope 

ranges are identified by bold type.

0–2 percent slope: Land surface is essentially flat, which 

maximizes the probability for potential contaminants to infiltrate into ground-water supplies.

2–6 percent slope: Land surface has a slightly rolling topography and opportunity exists for potential contaminants to 

infiltrate into ground-water supplies.

6–18 percent slope: Land surface has rolling topography, 

which encourages surface runoff and less infiltration of potential contaminants into ground-water supplies, compared to 

more mildly sloping areas.

18–35 percent slope: Land surface is steeply sloped, and 

surface runoff is likely. Infiltration of potential contaminants at 

any one point into ground-water supplies is reduced compared 

to milder slopes.

Greater than 35 percent slope: Land surface is very steeply 

sloped, and the potential for surface runoff of potential contaminants is greatest compared to other locations in Indiana. 

Conversely, it has the least probability for infiltration of potential contaminants to ground-water supplies.

A final qualitative description of the potential for susceptibility is the display of ground-water-altitude contours shown 

in figure 3 of the TNC reports. The ground-water flow direction relative to potential contaminant sites and the TNC supply 

is perpendicular to the contours in the direction of decreasing 

water-level altitude. The water-level contours were generated 

from over 100,000 water-level data values recorded by water-
12 Methods Used to Assess the Susceptibility to Contamination of Transient, Non-Community Public Ground-Water Supplies

well drillers on well logs submitted to the IDNR from approximately the 1960’s to 2002 (Indiana Department of Natural 

Resources, 2006).

Water-level altitude data were calculated from the each 

IDNR well log by subtracting the reported depth to water from 

the land-surface altitude at the well. Both data values were 

potential sources of error in the calculation, and both were 

checked for accuracy. Any land-surface value that varied by 

more than 15 ft from the elevation interpolated from the 

30-m DEM was removed from the data set, along with the 

associated water-level altitude before determining waterlevel contours. A water-level surface was developed from the 

remaining water-level altitude data by the use of a kriging 

interpolator available in ARC-INFO, version 8.3 (Environmental Systems Research Institute, 2003). Water-level surface 

altitudes were then compared to the individual point values 

of water-level altitude to determine if any point values varied 

greatly from the surface. If point values varied from the interpolated surface by more than 20 ft, then the point values were 

considered to be in error relative to the entire data set and were 

removed. A final water-level surface was reconstructed from 

the remaining point values. Contours shown in figure 3 of the 

TNC reports were generated using the final water-level surface 

developed from the reduced data set. The values of 15 and 

20 ft were chosen as cut-off values for their respective elevation and water-level data sets because they represented values 

that separated more common values from outliers.

Water-level data from all seasons of the year, all years, 

and all well depths were used in the kriging to obtain a longterm average water level. This type of water-level surface has 

been shown to be useful in determining regional ground-water 

flow directions (Fowler and Arihood, 1998, sheet 1). The 

ground-water flow directions inferred from the contours are 

a general indicator of long-term regional flow directions over 

all depths for which data were available. The water levels may 

not accurately reflect water levels in the aquifer from which 

a given TNC supply obtains water because they represent a 

regional condition and may contain measurement error. The 

contours shown in figure 3 of the TNC reports are intended 

to alert the public to the potential for ground-water flow to 

deliver contaminants to a TNC supply and to encourage further, site-specific flow-direction analysis.

Methods Used to Determine a Susceptibility 

Rating

The method for assigning a susceptibility rating to a 

TNC supply included qualitative analysis of susceptibility and 

subjective decisions combined with a quantitative (statistical) method. The combination of subjective and quantitative 

methods is called a subjective hybrid method (Focazio and 

others, 2002).

The susceptibility rating for TNC supplies is based on 

three factors:

1. Elevated concentrations of nitrate as nitrogen and the 

presence or absence of total-coliform bacteria reported in 

routine compliance monitoring of the TNC supply.

2. Presence or absence of potential sources of regulated 

COCs for TNC supplies within the assessment area, as 

reported by IDEM representatives during on-site visits.

3. Presence and thickness of a geologic barrier to contamination.

For this evaluation of susceptibility, the detection of 

coliform bacteria or a concentration of greater than 3 mg/L of 

nitrate as nitrogen in the analyses of any compliance-monitoring sample from a TNC well was considered an indicator that 

contaminants could reach the TNC well screen. The presence 

of total coliform as an indicator is based on the Indiana maximum permissible level of nondetect for total-coliform bacteria 

in drinking-water supplies obtained from ground water (Indiana Administrative Code, 2006). The value of greater than 

3.0 mg/L nitrate as nitrogen as an indicator was derived from 

a sensitivity classification scheme for nitrate sources based on 

concentrations in ground water (Madison and Brunett, 1984, 

p. 95) (table 3). For the remainder of this report, nitrate and 

nitrate plus nitrite are reported in concentration as nitrogen.

Table 3. Classification of nitrate source based upon range of concentration in ground water.

[mg/L, milligrams per liter; N, nitrogen; USEPA, U.S. Environmental Protection Agency; MCL, maximum contaminant level]

Range of concentrations of nitrate 

or nitrate plus nitrite Nitrate source as an indicator of sensitivity classification

Less than 0.2 mg/L as N Assumed to represent natural background conditions

0.21 to 3.0 mg/L as N Transitional; Concentrations that may or may not represent 

human influence

3.1 to 10 mg/L as N May indicate elevated concentrations resulting from human 

activity

Greater than 10 mg/L as N Exceeds USEPA MCL for nitrate

Source: Madison and Brunett, 1984, p. 95.
The presence or absence of potential sources of regulated 

COCs within the assessment area was determined during site 

visits by IDEM representatives as described in the section 

“Presence of Potential Sources and Associated Contaminants 

of Concern.”

The term “geologic barrier” is used by IDEM in their 

source-water assessment plan (Indiana Department of Environmental Management, 2000, p. 19) and is a convenient way 

to refer to the relative protection afforded by fine-grained 

geologic materials above the TNC well screen. Ground-water 

contamination can occur when surface contaminants are able 

to travel vertically through overlying geologic materials to 

the pumped aquifer. Fine-grained geologic materials, such as 

clay, silt, and shale, provide resistance to vertical flow and 

can slow the movement of contaminants greatly, as compared 

to coarser-grained geologic materials. Also, fine-grained 

geologic materials can filter out many particle-bound contaminants and facilitate chemical reactions that change the 

contaminant properties of many substances. For example, 

concentrations of nitrate are lowest in aquifers within lowpermeability clay-rich tills (Mueller and others, 1995, 

p. 25). The report by Mueller and others (1995) attributed the 

low concentrations of nitrate to decreased water infiltration 

through fine-grained soils and tills to the aquifers and to denitrification of nitrate in low-oxygen environments. The capability of clays and silts to provide flow resistance, filtering, 

and beneficial chemical reactions has lead to IDEM’s use of 

“geologic barrier” as a descriptor in the SWA reports for TNC 

supplies. The greater the thickness of fine-grained geologic 

materials, the more effective the geologic barrier becomes at 

diminishing infiltration rates and decreasing the probability of 

contamination in an underlying aquifer. Therefore, determining the total thickness of fine-grained geologic materials above 

a TNC well screen is part of Indiana’s susceptibility analysis.

The thickness of fine-grained geologic materials above 

the well screen for the TNC supply could be estimated 

using the geologic records from the IDNR well-log database 

(Indiana Department of Natural Resources, 2006). The IDNR 

database contained records for more than 134,000 wells, and 

it was not practical within the scope of this project to match 

the records for an individual well log to a corresponding TNC 

supply well. Therefore, well logs near (2-mi radius) the TNC 

supply well were used to estimate a thickness of fine-grained 

geologic materials above the well screen. At least three wells 

logs had to be available within 2 mi of the TNC supply well to 

provide sufficient data to interpolate a fine-grained thickness 

near the TNC supply. The wells had to surround the TNC supply and represent most of the same vertical section of geologic 

materials as encountered by the TNC well. Of the approximately 2,400 TNC supplies, only 83 (3 percent) were lacking 

at least 3 surrounding wells, and a thickness estimate of finegrained geologic materials could not be determined. About 

75 percent of the TNC supplies had 20 or more surrounding 

wells on which to base an estimate of fine-grained thickness.

The thickness of fine-grained geologic materials above 

the TNC well screen was dependent upon the depth of the 

TNC well, which was not always known. Well depths for TNC 

wells with unknown depths were estimated as described in the 

section “Hydrogeologic and Geomorphic Descriptions.” 

A computer program read well-log information for the wells 

near the TNC supply down to the depth (estimated or actual) 

of the TNC well. The thickness of fine-grained geologic materials was summed for each well, and the total thickness was 

assigned to the well for subsequent mapping of thickness. The 

total-thickness values were interpolated with an ARC-INFO 

procedure called inverse distance weighting (Environmental 

Systems Research Institute, 2003) to obtain a spatially continuous distribution of fine-grained geologic-material thickness 

around the TNC supply. After the thickness was interpolated, 

the thickness value at the location of the TNC supply was 

determined. The maximum potential calculated thickness for 

the fine-grained geologic materials was set to be equal to the 

depth of the well minus 3 ft to account for the well screen.

To determine the fine-grained thickness above a TNC 

well screen, the geologic records were classified as fine or 

coarse grained. Geologic records in the IDNR database first 

were classified according to the corresponding lithology 

descriptions and codes used in the USGS National Water 

Information System (NWIS) database (Babcock and others, 

2005), then each NWIS code was classified as either fine or 

coarse grained. The lithology descriptions and their classifications are recorded in table 4.

A quantitative relation was developed between thickness 

of fine-grained geologic material above the TNC well screen 

and reduction in the susceptibility to contamination. The relation describes the decrease in concentrations of contaminants 

with increasing thickness of fine-grained geologic materials. 

Concentrations of nitrate were used to represent the decrease 

in concentrations of contaminants with increasing thickness of 

fine-grained geologic materials.

The nitrate data were obtained from the NWIS database 

maintained by the USGS and from the Indiana Department of 

Natural Resources (2000). Well sites in NWIS were included 

in the data set if they contained a well depth and at least one 

analysis of nitrate or nitrate plus nitrite. If analyses of multiple samples were available for a given well, then only the 

analysis of the most recent sample was retained for this data 

set. The nitrate analyses from the IDNR were part of a data set 

representing ambient ground-water chemistry collected during 

water-resource assessments (Indiana Department of Natural 

Resources, 2000); these data are further described as the IDNR 

water-resources assessment data set in Risch and Cohen (1995, 

tables 1 and 2, p. 7). The NWIS data included 1,019 wells with 

a well depth and a nitrate analysis for the period June 3, 1954 

to March 3, 2005, and the IDNR data included 892 wells with 

a well depth and a nitrate analysis for the period June 4, 1985 

to November 26, 1985 (Appendix 3).

The combined NWIS and IDNR data (Appendix 3) 

included analyses of filtered and unfiltered ground-water 

samples; no differentiation was made between the analyses 

of water samples collected using either of these procedures. 

Analytical values for nitrate were used where available; otherMethods Used to Assess the Susceptibility to Contamination 13
14 Methods Used to Assess the Susceptibility to Contamination of Transient, Non-Community Public Ground-Water Supplies

Table 4. U.S. Geological Survey National Water Information System lithologies and texture category for use in estimating thickness of 

fine-grained geologic materials above a well screen.

National Water Information 

System lithology 

description1

National Water 

Information 

System lithology 

code1

Categorized as 

fine-grained 

geologic material

Basalt BSLT Yes

Boulders BLDR No

Boulders and sand BLSD No

Boulders, silt, and clay BLSC Yes

Chert CHRT Yes

Clay CLAY Yes

Clay some sand CLSD Yes

Claystone CLSN Yes

Coal COAL No

Cobbles COBB No

Cobbles and sand COSD No

Cobbles, silt, and clay COSC Yes

Conglomerate CGLM No

Dolomite DLMT No

Drift DRFT No

Evaporite EVPR Yes

Granite GRNT Yes

Gravel GRVL No

Gravel and clay GRCL Yes

Gravel, cemented GRCM Yes

Gravel, sand, and silt GRDS Yes

Gravel, silt, and clay GRSC Yes

Gypsum GPSM Yes

Hard pan HRDP Yes

Igneous (undifferentiated) IGNS Yes

Limestone LMSN No

Limestone and Dolomite LMDM No

Loam LOAM Yes

National Water Information 

System lithology 

description1

National Water 

Information 

System lithology 

code1

Categorized as 

fine-grained 

geologic material

Loess LOSS Yes

Marl MARL Yes

Muck MUCK Yes

Mud MUD Yes

Other OTHR No

Overburden OBDN No

Peat PEAT Yes

Quartzite QRTZ Yes

Rock ROCK No

Rubble RBBL No

Sand SAND No

Sand and clay SDCL Yes

Sand and gravel SDGL No

Sand and silt SDST Yes

Sand, gravel, and clay SGVC Yes

Sand, some clay SNCL Yes

Sandstone SNDS No

Sandstone and shale SDSL Yes

Schist SCST Yes

Sedimentary 

(undifferentiated)

SDMN No

Shale SHLE Yes

Silt SILT Yes

Silt and clay STCL Yes

Siltstone SLSN Yes

Slate SLTE Yes

Soil SOIL Yes

Till TILL Yes

1

Source: Babcock and others, 2005, p. 105–113.
wise, analytical values for nitrate plus nitrite were used. The 

inclusion of nitrite in the analysis was not considered to be a 

source of meaningful error. Hem (1989, p. 124) reported that 

nitrite as nitrogen is seldom present in concentrations large 

enough to affect the ionic balance of nitrogen species in natural waters. Nolan and Hitt (2003, p. 7) indicate that concentrations of nitrite as nitrogen in ground-water samples collected 

by the National Water-Quality Assessment Program (which 

includes samples collected in Indiana) typically are negligible; 

therefore, concentrations of nitrate plus nitrite are referred to 

as concentrations of nitrate for the remainder of this discussion. If the analytical value was reported as being less than a 

detection limit, then a value equal to one-half of the detection 

limit was used in evaluating the relation between nitrate and 

fine-grained thickness.

The relation between the concentration of nitrate for 

a well and the thickness of fine-grained geologic materials 

above the well screen required an estimate of fine-grained 

thickness at the sampled well. An estimate of the thickness 

of fine-grained geologic materials above the screen of each 

well with a concentration of nitrate was calculated in the same 

manner as previously described for the TNC wells. At least 

three wells within a 2-mi radius surrounding the sampled 

well were required to estimate a fine-grained thickness. For 

the entire data set, approximately 88 percent (1,684 wells) 

had fine-grained-thickness estimates based on from 10 to 347 

surrounding wells; less than 1 percent (14 wells) had finegrained-thickness estimates based on three surrounding wells.

The relation between concentration of nitrate and thickness of fine-grained geologic materials above the well screen 

is shown in figure 4. The plot depicts a downward trend in 

concentration of nitrate with increasing fine-grained thickness. 

The trend was quantified with a statistical procedure called 

logistic regression.

A logistic regression procedure (SAS Institute, 1999) was 

used to quantify the relation between concentration of nitrate 

and thickness of fine-grained geologic materials above the 

well screen. The process of logistic regression uses a critical 

value for a condition to predict the probability of encountering 

the condition based upon one or more independent variables. 

Methods Used to Assess the Susceptibility to Contamination 15

Figure 4. Relation between concentrations of nitrate as nitrogen in ground water and the thickness 

of fine-grained geologic materials above the well screen in Indiana.

0 50 100 150 200 250 300

THICKNESS OF FINE-GRAINED GEOLOGIC MATERIALS ABOVE THE WELL SCREEN, IN FEET

0

10

20

30

40

50

60

70

80

CONCENTRATION OF NITRATE AS NITROGEN, IN MILLIGRAMS PER LITER
16 Methods Used to Assess the Susceptibility to Contamination of Transient, Non-Community Public Ground-Water Supplies

Values above or below the critical value define the condition. 

The condition used for this logistic regression was the state 

of water quality and the critical value was a concentration of 

nitrate of 3 mg/L as N or greater. Values greater than or equal 

to 3.1 mg/L as N indicate that nitrate in the aquifer may be 

from a surface contaminant (see table 3), but the value used in 

logistic regression was rounded to 3 mg/L as N for simplicity. 

The logistic-regression analysis related concentration of nitrate 

to thickness of fine-grained geologic material and yielded 

a probability of nitrate concentration being greater than or 

equal to 3 mg/L as N, based on the thickness of fine-grained 

geologic material above the well screen. The probability plot 

of concentration of nitrate being equal to or greater than 

3 mg/L as N is shown in figure 5. Additional details about 

logistic regression can be found in Helsel and Hirsch (1995).

The quality of the regression can be measured in terms of 

the statistical significance of the regression parameters and by 

the equation’s predictive ability. Table 5 provides the statistical 

analysis of the coefficients from the regression. The standard 

errors associated with the coefficient estimates are small relative to their values, and the p values (probability of the coefficient being zero) are less than 0.01 percent, which is highly 

significant. The predictive ability of the regression equation 

can be measured by Somers’ D (SAS Institute, 1999, p. 1955), 

which measures the rank correlation between the observed 

and predicted responses. That is, Somers’ D measures how 

consistently the increase in thickness of fine-grained geologic 

materials above the well screen corresponds to a decrease in 

concentration of nitrate for the observed data. The range of the 

Somers’ D statistic is from -1 (no predictive ability) to 1 (perfect predictive ability); Somers’ D for the regression is 0.438. 

Based upon these statistics, the regression equation adequately 

Figure 5. Probability of nitrate as nitrogen in ground water being greater than or equal to 3 milligrams per liter for various thicknesses 

of fine-grained geologic materials above the well screen in Indiana.

0 100 200 300

TOTAL THICKNESS OF FINE-GRAINED GEOLOGIC MATERIALS, IN FEET

0

10

20

30

40

PROBABILITY OF CONCENTRATION OF NITRATE AS NITROGEN BEING GREATER THAN OR EQUAL TO 3 MILLIGRAMS PER LITER

Table 5. Statistical characteristics of the logistic regression.

Variable Coefficients Standard error of 

the parameters p value

Intercept -0.7732 0.0976 0.0001

Fine-grained thickness -0.0290 0.0029 0.0001
estimates the probability of concentrations of nitrate in relation to total thickness of fine-grained geologic materials above 

the well screen.

The thickness of the geologic barrier at the TNC supply 

is the third of three factors that was used to determine a susceptibility rating for the TNC supply. The application of these 

factors to determine a susceptibility rating is illustrated in the 

flow chart (or decision tree) shown in figure 6.

The flow chart was used to determine a susceptibility 

rating for each TNC supply using the data compiled during 

the study. Each box of the flow chart represents the general 

conditions around the water supply relative to the three factors 

described previously. The chart is divided into four sections. 

The first section categorizes whether regulated contaminants 

are absent or present in the drinking water. This section has 

two possibilities:

1. There were no detections of elevated concentrations of 

nitrate (greater than 3 mg/L as N), and there were no 

detections of bacteria during compliance monitoring of 

water samples from the TNC supply.

2. Elevated concentrations of nitrate (greater than 3 mg/L as 

N) were detected and (or) bacteria were detected during 

compliance monitoring of water samples from the TNC 

supply; at least one of these conditions was present.

The second section categorizes potential sources of regulated contaminants (bacteria and nitrate) as absent or present 

in the assessment area. This section has two possibilities:

1. No potential sources of regulated contaminants were 

identified within the assessment area during on-site visits 

to the TNC supply.

 2. One or more potential sources of regulated contaminants 

within the assessment area were identified during on-site 

visits to the TNC supply.

The third section characterizes the thickness of fine-grained 

geologic materials (geologic barrier) into one of three categories:

1. THIN or NOT DETERMINED—The thickness of the 

geologic barrier is 45 ft or less or is unknown.

Methods Used to Assess the Susceptibility to Contamination 17

Figure 6. Process for determining the susceptibility rating of transient, non-community ground-water supplies in Indiana.

Presence of 

Contaminants

OR OR

Elevated Nitrate

Concentrations or Total

Coliform Present

Potential

Point or Non-Point

Sources Absent

Potential

Point or Non-Point

Sources Present

Thin or

Not

Determined

Thick Moderate

Thin or

Not

Determined

Thick Moderate

Susceptible Moderately

Susceptible

Not Currently

Susceptible

Elevated Concentrations of Nitrate Absent and Total Coliform Absent

Susceptibility 

Rating

Presence of 

Contaminants

Presence of 

Sources of 

Contaminants

Geologic

Barrier
18 Methods Used to Assess the Susceptibility to Contamination of Transient, Non-Community Public Ground-Water Supplies

2. MODERATE—The thickness of the geologic barrier 

ranges from greater than 45 to less than or equal to 75 ft.

3. THICK—The thickness of the geologic barrier is greater 

than 75 ft.

The definitions for a thin (less than or equal to 45 ft), 

moderate (greater than 45 ft to less than or equal to 75 ft), and 

thick (greater than 75 ft) geologic barrier were derived from 

a qualitative analysis of the probability plot in figure 5. The 

probability of elevated concentration of nitrate verses thickness of fine-grained geologic materials is redrawn in figure 7 

with additional information that helps to clarify choices for the 

thickness definitions. In figure 7A, a significant break in the 

steepest part of the slope occurs at about 45 ft. A single steep 

slope, as indicated by the red line, could be assigned to the 

probability plot from 0 to 45 ft of thickness. An incremental 

change in thickness from 0 to 45 ft represents a relatively large 

change in the probability of elevated nitrate, compared to other 

thickness ranges, and the probability of elevated nitrate is considered to be the most sensitive to a change in thickness within 

this range. Thicknesses from 0 to 45 ft have a large effect on 

the probability of elevated nitrate; therefore, thicknesses in 

this range are considered to be thin for the purpose of the flow 

chart.

At 75 ft (figure 7B), the probability of elevated nitrate is 

about 5 percent. Five percent is commonly used as an acceptable error percent, as in the 95 percent confidence interval. 

Alternatively, when the probability of an event is less than 5 

percent, then the risk of the event occurring is commonly considered acceptable. In the context of the flow chart, when the 

thickness of fine-grained geologic materials becomes greater 

than 75 ft, the risk of elevated concentrations of nitrate (and 

associated contamination) becomes 5 percent or less. At probabilities of 5 percent or less, the geologic barrier is considered 

to be thick and generally protective. Thicknesses greater than 

45 ft, but less than or equal to 75 ft, are considered to be moderate thicknesses and represent intermediate protection.

The fourth section of the flow chart characterizes the susceptibility of a TNC supply as one of three susceptibility ratings based on the three factors that indicate conditions around 

the public-water supply. The ratings are as follows:

1. NOT CURRENTLY SUSCEPTIBLE—This rating is 

assigned if all the factors above generally represent a 

lesser potential for contamination of the TNC supply by 

regulated contaminants. For example, no sources of contamination are present and the geologic barrier is thick.

2. MODERATELY SUSCEPTIBLE—This rating is assigned 

if the factors above are a mix of conditions that represent both a lesser potential for contamination and a 

greater potential for contamination of the TNC supply by 

regulated contaminants. For example, point and nonpoint 

sources could be absent, but the geologic barrier is thin.

3. SUSCEPTIBLE—This rating is assigned if elevated 

concentrations of nitrate or bacteria were detected during compliance monitoring, or the factors represent a 

greater potential for contamination of the TNC supply by 

regulated contaminants. For example, if point or nonpoint 

sources are present and the geologic barrier is thin, then 

the water supply is rated susceptible.

The susceptibility rating can be determined by choosing the boxes in the flow chart (fig. 6) that best describe the 

conditions around the water supply and following the arrows 

down to the final susceptibility rating. If compliance-monitoring data on nitrate or bacteria data are not available, then the 

susceptibility of the TNC supply to contamination could not 

be determined because no information was available for the 

first section of the flow chart. Less than 2 percent (43) of the 

TNC supplies could not be rated because they were new and 

no compliance-monitoring data were available. Only one of 

the TNC supplies was rated not currently susceptible, approximately 7 percent (164) were rated moderately susceptible, and 

approximately 91 percent (2,144) were rated susceptible. Of 

the 2,144 TNC supplies rated susceptible, approximately 79 

percent (1,694) had a detection of coliform bacteria or a concentration of nitrate as nitrogen greater than 3 mg/L in at least 

one compliance-monitoring sample.

Summary

Methods were developed to delineate assessment areas, 

inventory potential sources and associated contaminants, and 

analyze the susceptibility of transient, non-community (TNC) 

ground-water public supplies to contamination. Two types of 

methods were used: subjective and subjective hybrid. Subjective methods use professional judgment to analyze conditions 

and decide levels of classification. Subjective hybrid methods 

combine subjective decisions with quantitative hydrologic 

analyses.

Subjective methods were used to delineate the assessment areas for TNC supplies, inventory potential sources 

and associated contaminants, and qualitatively describe the 

susceptibility of the TNC supply. The Indiana Department of 

Environmental Management (IDEM) defined a 300-feet (ft) 

radius around the TNC supply as the assessment area for the 

well. The regulated contaminants for Indiana TNC supplies 

are nitrate as nitrogen and bacteria as total coliform. Potential 

sources of contaminants were determined by on-site visits 

within the assessment area and by data-base retrievals from 

computerized databases for the area outside the assessment 

area. A U.S. Environmental Protection Agency reference 

and information in the Toxics Release Inventory and Permit 

Compliance System databases were used to associate specific 

contaminants with identified potential sources. A qualitative 

description of the inherent susceptibility of the general area 

around the TNC supply was made based upon five hydrogeologic and geomorphic characteristics of the general area: 

typical geologic materials above the TNC well screen, surficial 
Figure 7. Intervals in which thickness of fine-grained geologic materials is considered thin, 

moderate, and thick. (A) From 0 to 45 feet fine-grained thickness is considered thin. (B) The 75-feet 

thickness is considered the transition between moderate and thick.

0 100 200 300

TOTAL THICKNESS OF FINE-GRAINED GEOLOGIC MATERIALS, IN FEET

0

10

20

30

40

5%

75

0 100 200 300

TOTAL THICKNESS OF FINE-GRAINED GEOLOGIC MATERIALS, IN FEET

0

10

20

30

40

45

A

B

PROBABILITY OF CONCENTRATION OF NITRATE AS NITROGEN TO BE GREATER THAN OR EQUAL TO 3 MILLIGRAMS PER LITER

Trend line of steepest slope

PROBABILITY OF CONCENTRATION OF NITRATE AS NITROGEN TO BE GREATER THAN OR EQUAL TO 3 MILLIGRAMS PER LITER

Methods Used to Assess the Susceptibility to Contamination 19
20 Methods Used to Assess the Susceptibility to Contamination of Transient, Non-Community Public Ground-Water Supplies

geology, regional aquifer system, land slope, and ground-water 

flow direction.

A subjective hybrid method was used in determining a 

susceptibility rating. The subjective hybrid method combined 

the results of a logistic regression analysis with subjective 

analyses of susceptibility and subjective definitions for low, 

moderate, and thick geologic barriers. The logistic regression 

determined the probability of elevated concentrations of nitrate 

(greater than or equal to 3 milligrams per liter as nitrogen 

(mg/L as N)) in ground-water associated with specific thicknesses of fine-grained geologic materials (geologic barrier) 

above the pumped aquifer. The geologic barrier was defined 

to be thin for thicknesses between 0 and 45 ft, moderate for 

thicknesses greater than 45 and less than or equal to 75 ft, and 

thick if greater than 75 ft. Characteristics of the probability 

plot and a 5 percent probability of elevated concentration of 

nitrate in ground-water were used to determine the definitions 

of thickness ranges for the geologic barrier.

Information collected for a TNC supply and the assessment area was used with a flow chart to determine a susceptibility rating. Each tier of the flow chart represented potential 

conditions in and around the TNC supply well. The first tier 

of the flow chart accounted for the exceedance of IDEM’s 

drinking-water standards for regulated contaminants of 

concern (COCs) in monitoring samples from the TNC water 

supply. The second tier accounted for the presence or absence 

of potential sources of COCs in the assessment area. The third 

tier accounts for the presence and thickness of a geologic barrier. Lastly, a susceptibility rating of currently not susceptible, 

moderately susceptible, or susceptible is determined based 

upon the values applied to the three tiers. A rating of susceptible was automatically given to a TNC supply with a detection 

of coliform bacteria or a concentration of nitrate greater than 

3 mg/L as N. Less than 2 percent (43) of the TNC supplies 

could not be rated because they were new and no compliancemonitoring data were available. Only one of the TNC supplies 

was rated not currently susceptible, approximately 7 percent 

(164) were rated moderately susceptible, and approximately 

91 percent (2,144) were rated susceptible. Of the 2,144 TNC 

supplies rated susceptible, approximately 79 percent (1,694) 

had a detection of coliform bacteria or a concentration of 

nitrate greater than 3 mg/L as N in at least one compliancemonitoring sample.

References Cited

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D.M., with revisions by Lenfest, L.W., and Atwood, J.W., 

2005, User’s Manual for the National Water Information 

System of the U.S. Geological Survey—Ground-Water 

Site-Inventory System, Chapter 2—NWIS Sitefile and 

Ground-Water Site-Inventory Coding Instructions, Section 

6—Geohydrologic units file components: U.S. Geological 

Survey Open-File Report 2005–1251, v. 4.4, p. 105–113., 

accessed December 1, 2006, at URL http://pubs.usgs.gov/

of/2005/1251/

Environmental Systems Research Institute, 2003, ARC–INFO, 

version 8.3: Redlands, Calif.

Fenelon, J.M., Bobay, K.E., and others, 1994, Hydrogeologic 

atlas of aquifers in Indiana: U.S. Geological Survey WaterResources Investigations Report 92–4142, 197 p.

Focazio, M.J., Reilly, T.E., Rupert, M.G., and Helsel, D.R., 

2002, Assessing ground-water vulnerability: U.S. Geological Survey Circular 1224, 33 p.

Fowler, K.K., and Arihood, L.D., 1998, Geohydrology and 

quality of ground water in unconsolidated aquifers near 

South Bend, Indiana: U.S. Geological Survey WaterResources Investigations Report 98–4139, 3 oversized 

sheets.

Freeze, R.A., and Cherry, J.A., 1979, Groundwater: Englewood Cliffs, N.J., Prentice-Hall, Inc., 604 p.

Gray, H.H., 1989, Quaternary geologic map of Indiana: Indiana Geological Survey Miscellaneous Map 49.

Helsel, D.R., and Hirsch, R.M., 1995, Statistical methods in 

water resources: New York, Elsevier Science Publishing 

Company, Inc., Studies in Environmental Science 49, 529 p.

Hem, J.D., 1989, Study and interpretation of the chemical 

characteristics of natural water: U.S. Geological Survey 

Water-Supply Paper 2254, 263 p.

Indiana Administrative Code, 2006, Title 327 Article 2, Water 

quality standards, accessed February 8, 2007, at URL 

http://www.ai.org/legislative/iac/title327.html

Indiana Department of Environmental Management, 2000, 

Indiana’s source water assessment plan: Indianapolis, Ind., 

Indiana Department of Environmental Management, 140 p.

Indiana Department of Natural Resources, 2000, Ground 

water chemistry: Indiana Department of Natural Resources, 

Division of Water Basin Studies, Publication number 108, 

digital data.
Indiana Department of Natural Resources, 2006, Water well 

record database, digital data, accessed December 1, 2006, at 

URL http://www.in.gov/dnrwater/ground_water/well_database/index.html

Indiana Geological Survey, 2004, Geographic Information 

System data set of petroleum wells in Indiana, digital data, 

accessed March 9, 2004, at URL http://igs.indiana.edu/

arcims/statewide/download.html

Madison, R.J., and Brunett, J.O., 1984, Overview of the occurrence of nitrate in ground water of the United States: U.S. 

Geological Survey Water-Supply Paper 2275, p. 93–105.

Mueller, D.K., Hamilton, P.A., Helsel, D.R., Hitt, K.J., and 

Ruddy, B.C., 1995, Nutrients in ground water and surface 

water of the United States—an analysis of data through 

1992: U.S. Geological Survey Water-Resources Investigations Report 95–4031, 74 p.

Nolan, B.T., and Hitt, K.T., 2003, Nutrients in ground waters 

beneath relatively undeveloped areas in the conterminous 

United States: U.S. Geological Survey Water-Resources 

Investigations Report 02–4289, 17 p.

Office of Management and Budget, 1987, Standard Industrial 

Classification Manual: Executive Office of the President, 

Office of Management and Budget, 705 p.

Risch, M.R., and Cohen, D.A., 1995, A computerized database of nitrate concentrations in Indiana ground water: U.S. 

Geological Survey Open-File Report 95–468, 17 p.

SAS Institute, Inc., 1999, SAS/STAT User’s guide, version 8, 

volume 2: Cary, N.C., 1307 p.

U.S. Department of Agriculture, 1977, Map of the soil associations of Indiana: Lafayette, Ind., AY–209, Indiana Soil 

Survey, U.S. Department of Agriculture, Purdue University, 

Agricultural Experiment Station.

U.S. Environmental Protection Agency, 1997, State source 

water assessment and protection programs guidance: Washington D.C., U.S. Environmental Protection Agency Report 

EPA 816–R–97–009 [variously paged].

U.S. Environmental Protection Agency, 1999, 1997 Toxics 

Release Inventory: Washington D.C., Office of Pollution 

Prevention and Toxics, EPA 745–R–99–003 [variously 

paged].

U.S. Environmental Protection Agency, 2001a, Envirofacts 

Data Warehouse, digital data, accessed October 2, 2001, 

at URL http://www.epa.gov/enviro/index_java.html

U.S. Environmental Protection Agency, 2001b, BASINS—

Better Assessment Science Integrating point and Nonpoint 

Sources, Version 3.0: Office of Water, Office of Science and 

Technology, Region 5, EPA–823–C–01–005, digital data.

U.S. Environmental Protection Agency, 2002, Current Drinking Water Standards, USEPA 816–F–02–013, accessed on 

January 2, 2003, at URL http://www.epa.gov/safewater/mcl.

html, which was accessed from URL http://www.epa.gov/

safewater/creg.html, which was accessed from URL 

http://www.epa.gov/safewater/standards.html

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Sources of Drinking Water Contamination Index, updated 

September 16th, 2004, digital data, accessed December 1, 

2006, at URL http://permanent.access.gpo.gov/lps21800/

www.epa.gov/safewater/swp/sources1.html

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Injection Control Program: Deep Wells (Class I), accessed 

May 15, 2007, at URL http://www.epa.gov/safewater/uic/

classi.html

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Injection Control Program: Oil and Gas Injection Wells 

(Class II), accessed May 15, 2007, at URL http://www.epa.

gov/safewater/uic/classii.html

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Injection Control Program: Mining Wells (Class III), 

accessed May 15, 2007, at URL http://www.epa.gov/safewater/uic/classiii.html

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Injection Control Program: Shallow Hazardous and Radioactive Injection Wells (Class IV), accessed May 15, 2007, at 

URL http://www.epa.gov/safewater/uic/classiv.html

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Injection Control Program: Shallow Injection Wells (Class 

V), accessed May 15, 2007, at URL http://www.epa.gov/

safewater/uic/classv/index.html

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Survey, digital data, accessed December 1, 2006, at URL 

http://eros.usgs.gov/products/elevation.html

References Cited 21
22 Methods Used to Assess the Susceptibility to Contamination of Transient, Non-Community Public Ground-Water Supplies
Appendixes 1–3

1. Example Transient, Non-Community Source-Water Assessment Report

2. Potential Sources of Drinking-Water Contamination Index

3. Concentrations of Nitrate and Thickness of Fine-Grained Geologic Materials Above the Well 

Screen in Indiana
24 Methods Used to Assess the Susceptibility to Contamination of Transient, Non-Community Public Ground-Water Supplies

Appendix 1. Example Transient, Non-Community Source-Water 

Assessment Report

Source Water Assessment 

Public Water Supply ID# XXXXXXX

Service Station #XX 

Public Water Supply ID# XXXXXXX

Service Station #XX 

Transient Non-community 

Name of County 

Name of City, Indiana

Safe Drinking Water Is Important. In 1996, Congress 

amended the Safe Drinking Water Act to provide funds for state agencies to 

perform source water assessments. The Indiana Source Water Assessment 

Plan defines the approach and strategy for promoting clean and safe drinking 

water, and for performing individual source water assessments for Indiana’s 

public drinking-water supplies. The assessments evaluate the safety of 

ground- and surface-water public drinking-water supplies, including that for 

Service Station #XX. The Indiana Department of Environmental 

Management (IDEM) has collected information from the assessment area, the 

area within a 300-ft radius around the well supplying water to Service Station 

#XX (figure 1). The U.S. Geological Survey has compiled this information 

and provided other state-wide environmental data. These data include 

available water-quality data, potential sources of contaminants, geologic 

information, and other environmental factors that may affect the potential for 

the drinking-water supply to become contaminated. This report summarizes 

these findings and includes several links for related information.

Water-Supply Information. The date that the well supplying 

water to Service Station #XX was drilled is not known. Based upon similar 

wells in the surrounding area, the estimated depth of the well is 45 feet, and 

the rated capacity of the well is not known. The three most abundant 

geologic materials above the water-bearing zone (typically called an aquifer) 

in order of thickness are clay, gravel, and shale. Water is disinfected and 

softened and treated to remove inorganics before being served to an average 

of 300 people per day. Additional information about this drinking-water 

supply can be seen in the public water supply data table.

What are the Potential Sources of Regulated 

Contaminants? Regulated contaminants in ground water for transient 

non-community drinking-water supplies may occur if potential sources of 

these contaminants are present. The regulated contaminants for transient noncommunity water supplies are bacteria (total coliform) and nitrate. The 

possibility that these contaminants are locally present near Service Station 

#XX is indicated by land-use information and by data collected during on-site 

visits to this public drinking-water supply. Potential contaminant sources

within the assessment area that may contribute to increased concentrations of 

bacteria and nitrate include pasture and septic systems. A potential 

contaminant source within the assessment area that may contribute to 

increased concentrations of nitrate is an area of lawn grass, golf course, or 

urban park. Data on bacteria and nitrate concentrations collected from 

drinking water supplied by Service Station #XX can be seen in the bacteria 

and nitrate tables.

What Are Other Potential Contaminant Sources?

For this source water assessment, a potential contaminant source is any 

activity, facility, or location that stores, handles, generates, or is associated 

with any of the ninety State-listed drinking water contaminants. Potential 

contaminant sources were identified by checking contaminant-related data 

bases and by on-site visits to the water system. Six land uses and four 

facilities (figures 2 and 3) that have the potential to be sources of nonregulated contaminants were found within the assessment area and two such 

facilities were found outside the assessment area and within the area of figure 

2. For a list of potential contaminants associated with the local land uses see 

the nonpoint-source contaminants table. A list of potential contaminants 

associated with facilities can be seen in the point-source contaminants table.
Appendix 1. Example Transient, Non-Community Source-Water 

Assessment Report—Continued

Appendix 1. Example Transient Non-Community Source-Water Assessment Report 25

Source Water Assessment 

Public Water Supply ID# XXXXXXX

Service Station #XX 

What Is The Effect Of The Environmental Setting?

The environmental setting around the drinking-water supply is an important 

factor influencing susceptibility to contamination. The following is a brief 

description of the environment as it relates to drinking-water supply 

susceptibility. The assessment area is mostly overlain by coarse-grained 

surficial geologic materials. Compared to clay or silt, these materials allow 

more surface water to infiltrate and provide less filtering action to water and 

potential contaminants entering the ground. This drinking-water supply lies 

within the Buried Sand And Gravel and Upper Weathered Bedrock regional 

aquifer systems. The general topography in the area around the drinkingwater supply is slightly rolling, and opportunity exists for spills to infiltrate 

into ground-water supplies. The general direction of ground-water flow is 

perpendicular to the ground-water altitude contours and in the direction of 

decreasing contour values in figure 3. Ground water also may locally flow 

radially toward the drinking-water supply during pumping.

What Is The Potential That Regulated 

Contaminants May Reach This Water Supply? The 

potential for contamination is evaluated using (1) the detection of elevated

nitrate concentrations and the presence of bacteria, (2) the presence of 

potential contaminant sources, and (3) the presence and thickness of a 

geologic barrier. The combination of these three factors provides an 

indication of the potential for a public drinking-water supply to be 

contaminated. Elevated concentrations of bacteria have been found in the 

drinking water supplied by Service Station #XX. One land use and two 

facilities within the assessment area have the potential to contribute bacteria 

to this drinking-water supply. Two land uses and two facilities within the 

assessment area have the potential to contribute nitrate to this drinking-water 

supply. For Service Station #XX, it was found that the thickness of the 

geologic barrier above the water-bearing zone is generally thin. The 

combination of these factors suggest this drinking-water supply is susceptible

to contamination. In some cases a potential source of contaminants is 

classified as both a land use and a facility, for example a residence with a 

septic system. 

How Can I Act On This Information? Promoting a clean 

and safe drinking-water supply is a primary goal of the Source Water 

Assessment program. The previous sections provide background information 

that may help interested parties in developing a source water protection 

program. The information will help to: 

(1) Increase local awareness of the source of drinking water 

(2) Recognize the factors affecting drinking-water quality 

(3) Focus available resources on sites and areas of greatest concern 

(4) Make land-use decisions compatible with maintaining clean water 

For more information on developing a local source water protection program 

or with questions or comments regarding this source water assessment contact 

the IDEM Drinking Water Branch at 800-451-6027. 
26 Methods Used to Assess the Susceptibility to Contamination of Transient, Non-Community Public Ground-Water Supplies

Appendix 1. Example Transient, Non-Community Source-Water

Assessment Report—Continued

Bacteria Data from the Indiana Department of Environmental Management 

Compliance Database for the Public-Water Supply PWSID XXXXXXX, 

Service Station #XX

[NOTE(S): —, data not available]

Date Sample type

Presence or 

absence of 

Escherichia coli 

(E.coli)

Presence or 

absence of 

fecal coliform

Presence or 

absence of 

total coliform

1/18/1995 Distribution sample — — Absent

4/7/1995 Distribution sample — — Absent

10/11/1995 Distribution sample — — Absent

1/4/1996 Distribution sample — — Absent

6/7/1996 Distribution sample — — Absent

11/14/1996 Distribution sample — Absent Present

11/14/1996 Distribution sample — Absent Present

11/14/1996 Distribution sample — Absent Present

11/14/1996 Distribution sample — Absent Present

12/4/1996 Distribution sample — Absent Present

4/1/1997 Distribution sample — — Absent

4/1/1997 Distribution sample — — Absent

4/14/1997 Distribution sample — — Absent

6/16/1997 Distribution sample — — Absent

7/23/1997 Distribution sample — — Absent

9/12/1997 Routine sample — Absent Absent

12/8/1997 Routine sample — Absent Absent

3/24/1998 Routine sample — Absent Absent

6/17/1998 Routine sample — Present Present

6/22/1998 Check sample — Absent Absent

9/21/1998 Routine sample — Absent Absent

12/8/1998 Routine sample — Absent Absent

3/9/1999 Routine sample — Absent Absent

6/2/1999 Routine sample — Absent Absent

9/14/1999 Routine sample — Absent Absent

12/9/1999 Routine sample — Absent Absent

3/7/2000 Routine sample — Absent Absent
Appendix 1. Example Transient, Non-Community Source-Water

Assessment Report—Continued

Bacteria Data from the Indiana Department of Environmental Management 

Compliance Database for the Public-Water Supply PWSID XXXXXXX, 

Service Station #XX

[NOTE(S): —, data not available]

Date Sample type

Presence or 

absence of 

Escherichia coli 

(E.coli)

Presence or 

absence of 

fecal coliform

Presence or 

absence of 

total coliform

6/7/2000 Routine sample — Absent Absent

9/11/2000 Routine sample — Absent Absent

12/6/2000 Routine sample — Absent Absent

1/4/2001 Routine sample — Absent Absent

1/5/2001 Routine sample — Absent Absent

3/5/2001 Routine sample — Absent Absent

4/5/2001 Routine sample — Absent Absent

4/6/2001 Routine sample — Absent Absent

6/5/2001 Routine sample — Absent Absent

7/10/2001 Routine sample — Absent Absent

7/10/2001 Routine sample — Absent Absent

12/17/2001 Routine sample — Absent Absent

5/9/2002 Routine sample — Absent Absent

8/27/2002 Routine sample — Absent Absent

11/14/2002 Routine sample Absent Absent Present

11/21/2002 Check sample — Absent Absent

11/21/2002 Check sample — Absent Absent

11/21/2002 Check sample — Absent Absent

11/21/2002 Check sample — Absent Absent

3/10/2003 Routine sample — — Absent

6/18/2003 Routine sample — — Absent

9/30/2003 Routine sample — — Absent

3/8/2004 Routine sample — — Absent

6/14/2004 Routine sample — — Absent

9/29/2004 Routine sample — — Absent

12/9/2004 Routine sample — — Absent

Appendix 1. Example Transient Non-Community Source-Water Assessment Report 27
28 Methods Used to Assess the Susceptibility to Contamination of Transient, Non-Community Public Ground-Water Supplies

Appendix 1. Example Transient, Non-Community Source-Water

Assessment Report—Continued

Nitrate and Nitrite Data from the Indiana Department of Environmental 

Management Compliance Database for the Public-Water Supply PWSID 

XXXXXXX, Service Station #XX

[NOTE(S): —, data not available; <MRL, actual concentration less than the reporting limit of the method used to determine 

the concentration]

Date Entry point Sample type

Nitrate (as N) 

(milligrams

per liter)

Nitrate plus 

nitrite (as N)

(milligrams

per liter

Nitrite (as N)

(milligrams

per liter)

12/9/1994 EP001 Routine sample 0.01 — —

10/13/1995 EP001 Routine sample 0.5 — 0.005

9/18/1996 EP001 Routine sample 0.12 — 0.03

9/12/1997 EP001 Routine sample 1.14 — 0.04

9/21/1998 EP001 Routine sample 0.22 — 0.04

9/14/1999 EP001 Routine sample 0.01 — —

9/11/2000 EP001 Routine sample 0 — —

9/18/2001 EP001 Routine sample 0 — —

9/16/2002 EP001 Routine sample 0 — —

12/8/2004 EP001 Routine sample 0 <MRL 0 <MRL 0 <MRL
Appendix 1. Example Transient Non-Community Source-Water Assessment Report 29

Appendix 1. Example Transient, Non-Community Source-Water Assessment Report—Continued

Inventory of Potential Point Sources of Contaminants of Concern near the Public-Water Supply PWSID XXXXXXX, Service Station #XX.

Name Type of activity Location method Data source

Potential regulated contaminants of 

concern associated with this type of 

activity. Listed contaminants may or 

may not be present.

Potential contaminants of concern associated 

with this type of activity. Listed contaminants

 may or may not be present.

SERVICE STATION XX

GAS STATIONS (SEE ALSO ABOVE GROUND/UNDERGROUND STORAGE TANKS, MOTOR-VEHICLE DRAINAGE WELLS), RETAIL OPERATIONS, SEPTIC SYSTEMS

OFFSET GPS INSIDE 

ASSESSMENT AREA, SITE VISIT

BACTERIA AND NITRATE 1,1,1-TRICHLOROETHANE OR METHYL CHLOROFORM, 

1,2-DICHLOROETHANE OR ETHYLENE DICHLORIDE, 2,4-D, ALACHLOR, ARSENIC, ATRAZINE, BARIUM, BENZENE, CADMIUM, CARBOFURAN, CIS 1,2-DICHLOROETHYLENE, COLIFORM, CRYPTOSPORIDIUM, DALAPON, DICHLOROMETHANE OR METHYLENE CHLORIDE, DIQUAT, GIARDIA LAMBLIA, GLYPHOSATE, LEAD, MERCURY, NITRATE, NITRITE, OXAMYL (VYDATE), PICLORAM, SIMAZINE, STYRENE, SULFATE, TETRACHLOROETHYLENE OR PERCHLORETHYLENE (PERC), TOLUENE, TRANS 1,2-DICHLOROETHYLENE, TRICHLOROETHYLENE (TCE), VINYL CHLORIDE, VIRUSES (ENTERIC)

RESIDENTIAL AREA

FLEET/TRUCKING/BUS TERMINALS, SEPTIC SYSTEMS

OFFSET GPS INSIDE 

ASSESSMENT AREA, SITE VISIT

BACTERIA AND NITRATE 1,1,1-TRICHLOROETHANE OR METHYL CHLOROFORM, 

1,2-DICHLOROBENZENE OR O-DICHLOROBENZENE, 1,2-DICHLOROETHANE OR ETHYLENE DICHLORIDE, 1,4-DICHLOROBENZENE OR P-DICHLOROBENZENE, 2,4-D, ACRYLAMIDE, ALACHLOR, ARSENIC, ATRAZINE, BARIUM, BENZENE, BENZO(A)PYRENE, CADMIUM, CARBOFURAN, CARBON TETRACHLORIDE, CHLOROBENZENE, CIS 1,2-DICHLOROETHYLENE, COLIFORM, CRYPTOSPORIDIUM, CYANIDE, DALAPON, DI(2-ETHYLHEXYL) PHTHLATE, DICHLOROMETHANE OR METHYLENE CHLORIDE, DIQUAT, EPICHLOROHYDRIN, GIARDIA LAMBLIA, GLYPHOSATE, HEPTACHLOR EPOXIDE, LEAD, MERCURY, METHOXYCHLOR, NITRATE, NITRITE, OXAMYL (VYDATE), PENTACHLOROPHENOL, PICLORAM, PROPYLENE DICHLORIDE OR 1,2-DICHLOROPROPANE, SELENIUM, SIMAZINE, STYRENE, SULFATE, TETRACHLOROETHYLENE OR PERCHLORETHYLENE (PERC), TOLUENE, TOXAPHENE, TRANS 1,2-DICHLOROETHYLENE, TRICHLOROETHYLENE (TCE), VINYL CHLORIDE, VIRUSES (ENTERIC), XYLENE (MIXED ISOMERS)
30 Methods Used to Assess the Susceptibility to Contamination of Transient, Non-Community Public Ground-Water Supplies Appendix 1. Example Transient, Non-Community Source-Water Assessment Report—Continued Inventory of Potential Point Sources of Contaminants of Concern near the Public-Water Supply PWSID XXXXXXX, Service Station #XX.—Continued Name Type of activity Location method Data source Potential regulated contaminants of concern associated with this type of activity. Listed contami- nants may or may not be present. Potential contaminants of concern associated with this type of activity. Listed contaminants may or may not be present. WASHINGON ST. - US 40 TRANSPORTATION CORRIDORS (E.G., ROADS, RAILROADS) OFFSET GPS INSIDE ASSESSMENT AREA, SITE VISIT DALAPON, PICLORAM, SIMAZINE, SODIUM, SODIUM CHLORIDE, TURBIDITY EAST FORK WHITE LICK CREEK WATER BODY OFFSET GPS INSIDE ASSESSMENT AREA, SITE VISIT NONE KNOWN SERVICE STATION 22 AUTOMOBILE, BODY/ REPAIR SHOPS GPS (PSEUDO RANGE) DIFFERENTIAL OUTSIDE ASSESSMENT AREA, FROM ELECTRONIC DATA BASES 1,1,1-TRICHLOROETHANE, ARSENIC, BARIUM, BENZENE, CADMIUM, CHLOROBENZENE (MONOCHLOROBENZENE), CIS-1,2-DICHLOROETHYLENE, COPPER, DICHLOROMETHANE, FLUORIDE, LEAD, MERCURY, P-DICHLOROBENZENE, TETRACHLOROETHYLENE, TRANS-1,2- DICHLOROETHYLENE, TRICHLOROETHYLENE, XYLENES (TOTAL) LOCAL AIRPORT UNDERGRND STORAGE TANK/LEAKY UNDERGRND STORAGE TANK ADDRESS MATCHING- HOUSE NUMBER OUTSIDE ASSESSMENT AREA, FROM ELECTRONIC DATA BASES ARSENIC, BARIUM, BENZENE, CADMIUM, CIS- 1,2-DICHLOROETHYLENE, DICHLOROMETHANE, LEAD, P-DICHLOROBENZENE, TETRACHLOROETHYLENE, TRANS-1,2- DICHLOROETHYLENE, TRICHLOROETHYLENE
Appendix 1. Example Transient Non-Community Source-Water Assessment Report 31

Appendix 1. Example Transient, Non-Community Source-Water Assessment Report—ContinuedInventory of Potential Nonpoint Sources of Contaminants of Concern near the Public-Water Supply PWSID XXXXXXX, Service Station #XX.—Continued

Well 

number Land use

Percent of the 

area within 

300 feet of the 

well

Potential regulated contaminants 

of concern associated with this 

land use. Listed contaminants 

may or may not be present.

Potential contaminants of concern associated 

with this land use. Listed contaminants 

may or may not be present.

1 PAVED 40 DALAPON, PICLORAM, SIMAZINE, SODIUM, SODIUM CHLORIDE, TURBIDITY

1 LAWN GRASS 25 NITRATE ONLY 2,4-D, ARSENIC, ATRAZINE, BENZENE, CARBOFURAN, CHLOROBENZENE, DALAPON, 

DIQUAT, GLYPHOSATE, LEAD, METHOXYCHLOR, NITRATE, NITRITE, PICLORAM, SIMAZINE, TURBIDITY

1 COMMERCIAL 

BUILDING

15 1,1,1-TRICHLOROETHANE OR METHYL CHLOROFORM, 1,2-DICHLOROBENZENE OR 

O-DICHLOROBENZENE, 1,2-DICHLOROETHANE OR ETHYLENE DICHLORIDE, 2,4-D, BARIUM, BENZENE, CADMIUM, COPPER, DIAZINON, DICHLOROMETHANE OR METHYLENE CHLORIDE, DIQUAT, ETHYLBENZENE, GLYPHOSATE, LEAD, MERCURY, SELENIUM, SIMAZINE, TETRACHLOROETHYLENE OR PERCHLORETHYLENE (PERC), TRICHLOROETHYLENE (TCE), VINYL CHLORIDE, XYLENE (MIXED ISOMERS) 

1 GRAVEL 10 DALAPON, PICLORAM, SIMAZINE, SODIUM, SODIUM CHLORIDE, TURBIDITY1 WATER 5 NONE KNOWN1 PASTURE 5 BACTERIA AND NITRATE COLIFORM, CRYPTOSPORIDIUM, GIARDIA LAMBLIA, NITRATE, 

NITRITE, SULFATE, TURBIDITY, VIRUSES (ENTERIC)
32 Methods Used to Assess the Susceptibility to Contamination of Transient, Non-Community Public Ground-Water Supplies

Appendix 2. Potential Sources of Drinking-Water Contamination Index.—

Continued

[UIC, Underground injection control; Vet, Veterinary; RV, recreational vehicle]

Potential source Contaminant of concern

Commercial / industrial 

Above-ground storage tanks Arsenic, Barium, Benzene, Cadmium, 1,4-Dichlorobenzene or p-Dichlorobenzene, cis-1,2-

Dichloroethylene, trans-1,2-Dichloroethylene, Dichloromethane or Methylene Chloride, Lead, 

Trichloroethylene (TCE), Tetrachloroethylene or Perchlorethylene (Perc) 

Automobile, Body Shops/Repair Shops Arsenic, Barium, Benzene, Cadmium, Chlorobenzene, Copper, cis-1,2-Dichloroethylene, 

trans-1,2-Dichloroethylene, 1,4-Dichlorobenzene or p-Dichlorobenzene, Lead, Fluoride, 

1,1,1-Trichloroethane or Methyl Chloroform, Dichloromethane or Methylene Chloride, 

Tetrachloroethylene or Perchlorethylene (Perc), Trichloroethylene (TCE), Xylene (Mixed 

Isomers) 

Boat Repair/Refinishing/Marinas Benzene, Cadmium, cis-1,2-Dichloroethylene, Coliform, Cryptosporidium, Dichloromethane 

or Methylene Chloride, Giardia Lamblia, Lead, Mercury, Nitrate, Nitrite, trans-1,2-

Dichloroethylene, Tetrachloroethylene or Perchlorethylene (Perc), Trichloroethylene (TCE), 

Vinyl Chloride, Viruses 

Cement/Concrete Plants Barium, Benzene, Dichloromethane or Methylene Chloride, Ethyl Benzene, Lead, Styrene, 

Tetrachloroethylene or Perchlorethylene (Perc), Toluene, Xylene (Mixed Isomers) 

Chemical/Petroleum Processing Acrylamide, Arsenic, Atrazine, Alachlor, Aluminum (Fume or Dust), Barium, Benzene, 

Cadmium, Carbofuran, Carbon Tetrachloride, Chlorobenzene, Copper, Cyanide, 2,4-D, 1,2-

Dibromoethane or Ethylene Dibromide (EDB), 1,2-Dichlorobenzene or o-Dichlorobenzene, 

1,4-Dichlorobenzene or p-Dichlorobenzene, 1,1-Dichloroethylene or Vinylidene Chloride, 

cis-1,2-Dichloroethylene, Dichloromethane or Methylene Chloride, Di(2-ethylhexyl) 

adipate, Di(2-ethylhexyl) phthalate, 1,2-Dichloroethane or Ethylene Dichloride, Dioxin, 

Endrin, Epichlorohydrin, Ethyl Benzene, Hexachlorobenzene, Hexachlorocyclopentadiene, 

Lead, Mercury, Methoxychlor, Polychlorinated Biphenyls, Selenium, Styrene, Sulfate, 

Tetrachloroethylene or Perchlorethylene (Perc), Toluene, 1,2,4-Trichlorobenzene, 1,1,1-

Trichloroethane or Methyl Chloroform, Trichloroethylene (TCE), Vinyl Chloride, Xylene 

(Mixed Isomers), Zinc (Fume or Dust) 

Construction/Demolition Arsenic, Asbestos, Benzene, Cadmium, Chloride, Copper, Cyanide, cis-1,2-Dichloroethylene, 

trans-1,2-Dichloroethylene, Dichloromethane or Methylene Chloride, Fluorides, Lead, 

Selenium, Tetrachloroethylene or Perchlorethylene (Perc), 1,1,1-Trichloroethane or Methyl 

Chloroform, Trichloroethylene (TCE), Turbidity, Xylene (Mixed Isomers), Zinc (Fume or 

Dust) 

Dry Cleaners/Dry Cleaning Tetrachloroethylene or Perchlorethylene (Perc), 1,1,1-Trichloroethane or Methyl Chloroform, 

1,1,2-Trichloroethane 

Dry Goods Manufacturing Barium, Benzene, Cadmium, Copper, Dichloromethane or Methylene Chloride, Di(2-ethylhexyl) 

phthalate, Lead, 1,1,1-Trichloroethane or Methyl Chloroform, Polychlorinated Biphenyls, 

Tetrachloroethylene or Perchlorethylene (Perc), Toluene, Trichloroethylene (TCE), Xylene 

(Mixed Isomers) 

Electrical/Electronic Manufacturing Aluminum (Fume or Dust), Antimony, Arsenic, Barium, Benzene, Cadmium, Chlorobenzene, 

Copper, Cyanide, Carbon Tetrachloride, 1,2-Dichlorobenzene or o-Dichlorobenzene, 1,2-

Dichloroethane or Ethylene Dichloride, cis-1,2-Dichloroethylene, trans-1,2-Dichloroethylene, 

Dichloromethane or Methylene Chloride, Di(2-ethylhexyl) phthalate, Ethyl Benzene, Lead, 

Mercury, Polychlorinated Biphenyls, Selenium, Styrene, Sulfate, Tetrachloroethylene or 

Perchlorethylene (Perc), 1,1,1-Trichloroethane or Methyl Chloroform, 1,1,2-Trichloroethane, 

Trichloroethylene (TCE), Thallium, Toluene, Vinyl Chloride, Xylene (Mixed Isomers), Zinc 

(Fume or Dust) 
Appendix 2. Potential Sources of Drinking-Water Contamination Index.—

Continued

[UIC, Underground injection control; Vet, Veterinary; RV, recreational vehicle]

Potential source Contaminant of concern

Commercial / industrial—Continued

Fleet/Trucking/Bus Terminals Arsenic, Acrylamide, Barium, Benzene, Benzo(a)pyrene, Cadmium, Chlorobenzene, Cyanide, 

Carbon Tetrachloride, 2,4-D, 1,2-Dichlorobenzene or o-Dichlorobenzene, 1,4-Dichlorobenzene 

or p-Dichlorobenzene, 1,2-Dichloroethane or Ethylene Dichloride, cis-1,2-Dichloroethylene, 

trans-1,2-Dichloroethylene, Dichloromethane or Methylene Chloride, Di(2-ethylhexyl) 

phthalate, Epichlorohydrin, Heptachlor (and Epoxide), Lead, Mercury, Methoxychlor, 

Pentachlorophenol, Propylene Dichloride or 1,2-Dichloropropane, Selenium, Styrene, 

Toxaphene, Tetrachloroethylene or Perchlorethylene (Perc), Toluene, 1,1,1-Trichloroethane or 

Methyl Chloroform, Trichloroethylene (TCE), Vinyl Chloride, Xylene (Mixed Isomers) 

Food Processing Arsenic, Benzene, Cadmium, Copper, Carbon Tetrachloride, Dichloromethane or Methylene 

Chloride, Lead, Mercury, Picloram, Tetrachloroethylene or Perchlorethylene (Perc), Toluene, 

1,1,1-Trichloroethane or Methyl Chloroform, Trichloroethylene (TCE), Xylene (Mixed 

Isomers) 

Funeral Services/Taxidermy Glyphosate, Dichloromethane or Methylene Chloride, Nitrate, Nitrite, Total Coliforms, Viruses 

Furniture Repair/Manufacturing Barium, 1,2-Dichloroethane or Ethylene Dichloride, Dichloromethane or Methylene Chloride, 

Ethyl Benzene, Lead, Mercury, Selenium, Trichloroethylene (TCE) 

Gas Stations (see also above ground/

underground storage tanks, motor-vehicle drainage wells) 

cis-1,2-Dichloroethylene, trans-1,2-Dichloroethylene, Dichloromethane or Methylene Chloride, 

Tetrachloroethylene or Perchlorethylene (Perc), Trichloroethylene (TCE) 

Graveyards/Cemeteries Dalapon, Lindane, Nitrate, Nitrite, Total Coliforms, Viruses. 

Hardware/Lumber/Parts Stores Aluminum (Fume or Dust), Barium, Benzene, Cadmium, Chlorobenzene, Copper, 

Dichloromethane or Methylene Chloride, Di(2-ethylhexyl)adipate, Di(2-ethylhexyl) 

phthalate, 1,4-Dichlorobenzene or p-Dichlorobenzene, Ethyl Benzene, Lead, Mercury, 

Tetrachloroethylene or Perchlorethylene (Perc), 1,1,1-Trichloroethane or Methyl Chloroform, 

Trichloroethylene (TCE), Toluene, Xylene (Mixed Isomers) 

Historic Waste Dumps/Landfills Atrazine, Alachlor, Carbofuran, cis-1,2-Dichloroethylene, trans-1,2-Dichloroethylene, 

Diquat, Dalapon, Glyphosate, Dichloromethane or Methylene Chloride, Nitrate, Nitrite, 

Oxamyl (Vydate), Sulfate, Simazine, Tetrachloroethylene or Perchlorethylene (Perc), 

Trichloroethylene(TCE) 

Home Manufacturing Arsenic, Barium, Benzene, Cadmium, Chlorobenzene, Copper, Carbon Tetrachloride, 1,2-

Dichlorobenzene or o-Dichlorobenzene, cis-1,2-Dichloroethylene, trans-1,2-Dichloroethylene, 

Dichloromethane or Methylene Chloride, Di(2-ethylhexyl) phthalate, Ethyl Benzene, 

Lead, Mercury, Selenium, Styrene, Tetrachloroethylene or Perchlorethylene (Perc), 1,1,1-

Trichloroethane or Methyl Chloroform, Trichloroethylene (TCE), Toluene, Turbidity, Xylene 

(Mixed Isomers) 

Industrial Waste Disposal Wells Acrylamide, Arsenic, Atrazine, Alachlor, Aluminum (Fume or Dust), Ammonia, Barium, 

Benzene, Cadmium, Carbofuran, Carbon Tetrachloride, Chlorobenzene, Copper, Cyanide, 

2,4-D, 1,2-Dibromoethane or Ethylene Dibromide (EDB), 1,2-Dichlorobenzene or oDichlorobenzene, 1,4-Dichlorobenzene or p-Dichlorobenzene, 1,1-Dichloroethylene or 

Vinylidene Chloride, cis-1,2-Dichloroethylene, Dichloromethane or Methylene Chloride, Di(2-

ethylhexyl) adipate, Di(2-ethylhexyl) phthalate, 1,2-Dichloroethane or Ethylene Dichloride, 

Dioxin, Endrin, Epichlorohydrin, Hexachlorobenzene, Hexachlorocyclopentadiene, Lead, 

Mercury, Methoxychlor, Oxamyl (Vydate), Polychlorinated Biphenyls, Selenium, Styrene, 

Sulfate, Tetrachloroethylene or Perchlorethylene (Perc), Toluene, 1,2,4-Trichlorobenzene, 

1,1,1-Trichloroethane or Methyl Chloroform, Trichloroethylene (TCE), Vinyl Chloride, Xylene 

(Mixed Isomers), Zinc (Fume or Dust) 

Appendix 2. Potential Sources of Drinking-Water Contamination Index 33
34 Methods Used to Assess the Susceptibility to Contamination of Transient, Non-Community Public Ground-Water Supplies

Appendix 2. Potential Sources of Drinking-Water Contamination Index.—

Continued

[UIC, Underground injection control; Vet, Veterinary; RV, recreational vehicle]

Potential source Contaminant of concern

Commercial / industrial—Continued

Junk/Scrap/Salvage Yards Barium, Benzene, Copper, Dalapon, cis-1,2-Dichloroethylene, Diquat, Glyphosate, Lead, Polychlorinated Biphenyls, Sulfate, Simazine, Trichloroethylene (TCE), Tetrachloroethylene or 

Perchlorethylene (Perc) 

Machine Shops Arsenic, Aluminum (Fume or Dust), Barium, Benzene, Boric Acid, Cadmium, Chlorobenzene, 

Copper, Cyanide, Carbon Tetrachloride 2,4-D, 1,4-Dichlorobenzene or p-Dichlorobenzene, 

1,2-Dichloroethane or Ethylene Dichloride, 1,1-Dichloroethylene or Vinylidene Chloride, cis1,2-Dichloroethylene, trans-1,2-Dichloroethylene, Dichloromethane or Methylene Chloride, 

Di(2-ethylhexyl) phthalate, Ethyl Benzene, Fluoride, Hexachlorobenzene, Lead, Mercury, 

Polychlorinated Biphenyls, Pentachlorophenol, Selenium, Styrene, Tetrachloroethylene 

or Perchlorethylene (Perc), Toluene, 1,1,1-Trichloroethane or Methyl Chloroform, 1,1,2-

Trichloroethane, Trichloroethylene (TCE), Xylene (Mixed Isomers), Zinc (Fume or Dust) 

Metal Plating/Finishing/Fabricating Antimony, Aluminum (Fume or Dust), Arsenic, Barium, Benzene, Cadmium, Carbon 

Tetrachloride, Chlorobenzene, Chromium, Copper, Cyanide, 1,4-Dichlorobenzene or pDichlorobenzene, cis-1,2-Dichloroethylene, trans-1,2-Dichloroethylene, Dichloromethane or 

Methylene Chloride, Di(2-ethylhexyl) adipate, Ethyl Benzene, Lead, Mercury, Polychlorinated 

Biphenyls, Pentachlorophenol, Selenium, Styrene, Sulfate, Tetrachloroethylene or 

Perchlorethylene (Perc), , Thallium, Toluene, 1,1,1-Trichloroethane or Methyl Chloroform, 

1,1,2-Trichloroethane, Trichloroethylene(TCE), Vinyl Chloride, Xylene (Mixed Isomers), Zinc 

(Fume or Dust) 

Military Installations Arsenic, Barium, Benzene, Cadmium, Chlorobenzene, 1,2-Dichlorobenzene or oDichlorobenzene, 1,2-Dichloroethane or Ethylene Dichloride, cis-1,2-Dichloroethylene, 

trans-1,2-Dichloroethylene, Dichloromethane or Methylene Chloride, Hexachlorobenzene, 

Lead, Mercury, Methoxychlor, 1,1,1-Trichloroethane or Methyl Chloroform, Radionuclides, 

Selenium, Tetrachloroethylene or Perchlorethylene (Perc), , Toluene, Trichloroethylene (TCE) 

Mines/Gravel Pits Lead, Selenium, Sulfate, Tetrachloroethylene or Perchlorethylene (Perc), 1,1,1-Trichloroethane or 

Methyl Chloroform, Turbidity 

Motor Pools cis-1,2-Dichloroethylene, trans-1,2-Dichloroethylene, Dichloromethane or Methylene Chloride

Motor Vehicle Waste Disposal Wells 

(gas stations, repair shops) See 

Underground Injection Control 

website for more information about 

these sources (U.S. Environmental 

Protection Agency, 2006e) 

Arsenic, Barium, Benzene, Cadmium, Chlorobenzene, Copper, cis-1,2-Dichloroethylene, 

trans-1,2-Dichloroethylene, 1,4-Dichlorobenzene or p-Dichlorobenzene, Lead, Fluoride, 

1,1,1-Trichloroethane or Methyl Chloroform, Dichloromethane or Methylene Chloride, 

Tetrachloroethylene or Perchlorethylene (Perc), Trichloroethylene (TCE), Xylene (Mixed 

Isomers) 

Office Building/Complex Barium, Benzene, Cadmium, Copper, 2,4-D, Diazinon, 1,2-Dichlorobenzene or oDichlorobenzene, Dichloromethane or Methylene Chloride, Diquat, 1,2-Dichloroethane 

or Ethylene Dichloride, Ethyl Benzene, Glyphosate, Lead, Mercury, Selenium, Simazine, 

Tetrachloroethylene or Perchlorethylene (Perc), 1,1,1-Trichloroethane or Methyl Chloroform, 

Trichloroethylene (TCE), Vinyl Chloride, Xylene (Mixed Isomers) 
Appendix 2. Potential Sources of Drinking-Water Contamination Index.—

Continued

[UIC, Underground injection control; Vet, Veterinary; RV, recreational vehicle]

Potential source Contaminant of concern

Commercial / industrial—Continued

Photo Processing/Printing Acrylamide, Aluminum (Fume or Dust), Arsenic, Barium, Benzene, Cadmium, Carbon 

Tetrachloride, Chlorobenzene, Copper, Cyanide, 1,1-Dichloroethylene or Vinylidene Chloride, 

cis-1,2-Dichloroethylene, trans-1,2-Dichloroethylene, Dichloromethane or Methylene Chloride, 

Di(2-ethylhexyl) phthalate, 1,2-Dichlorobenzene or o-Dichlorobenzene, 1,4-Dichlorobenzene 

or p-Dichlorobenzene, 1,2-Dichloroethane or Ethylene Dichloride, 1,2-Dibromoethane 

or Ethylene Dibromide (EDB), Heptachlor epoxide, Hexachlorobenzene, Lead, Lindane, 

Mercury, Methoxychlor, Propylene Dichloride or 1,2-Dichloropropane, Selenium, Styrene, 

Tetrachloroethylene or Perchlorethylene (Perc), 1,1,1-Trichloroethane or Methyl Chloroform, 

Toluene, 1,1,2-Trichloroethane, Trichloroethylene(TCE), Vinyl Chloride, Xylene (Mixed 

Isomers), Zinc (Fume or Dust) 

Synthetic / Plastics Production Antimony, Arsenic, Barium, Benzene, Cadmium, Carbon Tetrachloride, Chlorobenzene, 

Copper, Cyanide, 1,2-Dichlorobenzene or o-Dichlorobenzene, 1,4-Dichlorobenzene or 

p-Dichlorobenzene, 1,2-Dichloroethane or Ethylene Dichloride, cis-1,2-Dichloroethylene, 

trans-1,2-Dichloroethylene, Dichloromethane or Methylene Chloride, Di(2-ethylhexyl) 

adipate, Di(2-ethylhexyl) phthalate, Ethyl Benzene, Hexachlorobenzene, Lead, Mercury, 

Methyl Chloroform or 1,1,1-Trichloroethane, Pentachlorophenol, Selenium, Styrene, 

Tetrachloroethylene or Perchlorethylene (Perk), Toluene,, Trichloroethylene (TCE), Vinyl 

Chloride, Xylene (Mixed Isomers), Zinc (Fume or Dust) 

RV/Mini Storage Arsenic, Barium, Cyanide, 2,4-D, Endrin, Lead, Methoxychlor 

Railroad Yards/Maintenance/Fueling 

Areas 

Atrazine, Barium, Benzene, Cadmium, Dalapon, 1,4-Dichlorobenzene or p-Dichlorobenzene, cis1,2-Dichloroethylene, trans-1,2-Dichloroethylene, Dichloromethane or Methylene Chloride, 

Lead, Mercury, Tetrachloroethylene or Perchlorethylene (Perc), Trichloroethylene (TCE). 

Research Laboratories Arsenic, Barium, Benzene, Beryllium Powder, Cadmium, Carbon Tetrachloride, Chlorobenzene, 

Cyanide, 1,2-Dichloroethane or Ethylene Dichloride, 1,1-Dichloroethylene or Vinylidene 

Chloride, cis-1,2-Dichloroethylene, trans-1,2-Dichloroethylene, Dichloromethane or 

Methylene Chloride, Endrin, Lead, Mercury, Polychlorinated Biphenyls, Selenium, 

Tetrachloroethylene or Perchlorethylene (Perc), Thallium, Thiosulfates, Toluene, 1,1,1-

Trichloroethane or Methyl Chloroform, Trichloroethylene (TCE), Vinyl Chloride, Xylene 

(Mixed Isomers) 

Residential / municipal 

Retail Operations Arsenic, Barium, Benzene, Cadmium, 2,4-D, 1,2-Dichloroethane or Ethylene Dichloride, 

Lead, Mercury, Styrene, Tetrachloroethylene or Perchlorethylene (Perc), Toluene, 1,1,1-

Trichloroethane, Vinyl Chloride 

Underground Storage Tanks Arsenic, Barium, Benzene, Cadmium, 1,4-Dichlorobenzene or p-Dichlorobenzene, cis-1,2-

Dichloroethylene, trans-1,2-Dichloroethylene, Dichloromethane or Methylene Chloride, Lead, 

Tetrachloroethylene or Perchlorethylene (Perc), Trichloroethylene (TCE)

Wood Preserving/Treating cis-1,2-Dichloroethylene, trans-1,2-Dichloroethylene, Lead, Sulfate 

Wood/Pulp/Paper Processing Arsenic, Barium, Benzene, Cadmium, Carbon Tetrachloride, Copper, Dichloromethane or 

Methylene Chloride, Dioxin, 1,2-Dichloroethane or Ethylene Dichloride, Ethyl Benzene, 

Lead, Mercury, Polychlorinated Biphenyls, Selenium, Styrene, Tetrachloroethylene or 

Perchlorethylene (Perc), Trichloroethylene (TCE), Toluene, 1,1,1-Trichloroethane or Methyl 

Chloroform, Xylene (Mixed Isomers) 

Appendix 2. Potential Sources of Drinking-Water Contamination Index 35
36 Methods Used to Assess the Susceptibility to Contamination of Transient, Non-Community Public Ground-Water Supplies

Appendix 2. Potential Sources of Drinking-Water Contamination Index.—

Continued

[UIC, Underground injection control; Vet, Veterinary; RV, recreational vehicle]

Potential source Contaminant of concern

Residential / municipal—Continued

Airports (Maintenance/Fueling Areas) Arsenic, Barium, Benzene, Cadmium, Carbon Tetrachloride, cis-1,2-Dichloroethylene, 

Dichloromethane or Methylene Chloride, Ethyl Benzene, Lead, Mercury, Selenium, 

Tetrachloroethylene or Perchlorethylene (Perc), 1,1,1-Trichloroethane or Methyl Chloroform, 

Trichloroethylene (TCE), Xylene (Mixed Isomers) 

Apartments and Condominiums Atrazine, Alachlor, Coliform, Cryptosporidium, Dalapon, Diquat, Giardia Lamblia, Glyphosate, 

Nitrate, Nitrite, Picloram, Sulfate, Simazine, Vinyl Chloride, Viruses 

Camp Grounds/RV Parks Benomyl, Coliform, Cryptosporidium, Diquat, Dalapon, Giardia Lamblia, Glyphosate, 

Isopropanol, Nitrate, Nitrite, Picloram, Sulfate, Simazine, Turbidity, Vinyl Chloride, Viruses 

Cesspools - Large Capacity (see UIC 

for more information) 

Atrazine, Alachlor, Carbofuran, Coliform, Cryptosporidium, Diquat, Dalapon, Giardia Lamblia, 

Glyphosate, Nitrate, Nitrite, Oxamyl (Vydate), Picloram, Sulfate, Simazine, Vinyl Chloride, 

Viruses 

Drinking Water Treatment Facilities Atrazine, Benzene, Cadmium, Cyanide, Fluoride, Lead, Polychlorinated Biphenyls, Toluene, 

Total Trihalomethanes, 1,1,1-Trichloroethane or Methyl Chloroform 

Gas Pipelines cis-1,2-Dichloroethylene, trans-1,2-Dichloroethylene, Dichloromethane or Methylene Chloride, 

Tetrachloroethylene or Perchlorethylene (Perc), Trichloroethylene or TCE 

Golf Courses and Urban Parks Arsenic, Atrazine, Benzene, Chlorobenzene, Carbofuran, 2,4-D, Diquat, Dalapon, Glyphosate, 

Lead, Methoxychlor, Nitrate, Nitrite, Picloram, Simazine, Turbidity 

Housing developments Atrazine, Alachlor, Coliform, Cryptosporidium, Carbofuran, Diquat, Dalapon, Giardia Lamblia, 

Glyphosate, Dichloromethane or Methylene Chloride, Nitrate, Nitrite, Picloram, Simazine, 

Trichloroethylene (TCE), Turbidity, Vinyl Chloride, Viruses 

Landfills/Dumps Arsenic, Atrazine, Alachlor, Barium, Benzene, Cadmium, Carbofuran, cis-1,2-Dichloroethylene, 

Diquat, Glyphosate, Lead, Lindane, Mercury, 1,1,1-Trichloroethane or Methyl Chloroform, 

Dichloromethane or Methylene Chloride, Nitrate, Nitrite, Picloram, Selenium, Simazine, 

Trichloroethylene (TCE) 

Public Buildings (e.g., schools, town 

halls, fire stations, police stations) 

and Civic Organizations 

Arsenic, Acrylamide, Barium, Benzene, Beryllium Powder, Cadmium, Carbon Tetrachloride, 

Chlorobenzene, Cyanide, 2,4-D, 1,2-Dichlorobenzene or o-Dichlorobenzene, 1,4-

Dichlorobenzene or p-Dichlorobenzene, Dichloromethane or Methylene Chloride, Di(2-

ethylhexyl) phthlate, 1,2-Dichloroethane or Ethylene Dichloride, Endothall, Endrin, 1,2-

Dibromoethane or Ethylene Dibromide (EDB), Lead, Lindane, Mercury, Methoxychlor, 

Selenium, Toluene, 1,1,1-Trichloroethane or Methyl Chloroform, Trichloroethylene (TCE), 

Vinyl Chloride, Xylene (Mixed Isomers) 

Septic Systems Atrazine, Alachlor, Carbofuran, Coliform, Cryptosporidium, Diquat, Dalapon, Giardia Lamblia, 

Glyphosate, Nitrate, Nitrite, Oxamyl (Vydate), Picloram, Sulfate, Simazine, Vinyl Chloride, 

Viruses 

Sewer Lines Coliform, Cryptosporidium, Diquat, Dalapon, Giardia Lamblia, Glyphosate, Nitrate, Nitrite, 

Oxamyl (Vydate), Picloram, Sulfate, Simazine, Vinyl Chloride, Viruses 

Stormwater infiltration basins/injection into wells (UIC Class V), runoff 

zones 

Atrazine, Alachlor, Coliform, Cryptosporidium, Carbofuran, Chlorine, Diquat, Dalapon, Giardia 

Lamblia, Glyphosate, Dichloromethane or Methylene Chloride, Nitrate, Nitrite, Nitrosamine, 

Oxamyl (Vydate), Phosphates, Picloram, Simazine, Trichloroethylene (TCE), Turbidity, Vinyl 

Chloride, Viruses 

Transportation Corridors (e.g., Roads, 

railroads) 

Dalapon, Picloram, Simazine, Sodium, Sodium Chloride, Turbidity 
Appendix 2. Potential Sources of Drinking-Water Contamination Index.—

Continued

[UIC, Underground injection control; Vet, Veterinary; RV, recreational vehicle]

Potential source Contaminant of concern

Residential / municipal—Continued

Utility Stations Arsenic, Barium, Benzene, Cadmium, Chlorobenzene, Cyanide, 2,4-D, 1,4-Dichlorobenzene 

or p-Dichlorobenzene, 1,2-Dichloroethane or Ethylene Dichloride, cis-1,2-Dichloroethylene, 

trans-1,2-Dichloroethylene, Dichloromethane or Methylene Chloride, Lead, Mercury, 

Picloram, Toluene, 1,1,2,2- Tetrachloroethane, Tetrachloroethylene or Perchlorethylene (Perc), 

Trichloroethylene (TCE), Xylene (Mixed Isomers) 

Waste Transfer /Recycling Coliform, Cryptosporidium, Giardia Lamblia, Nitrate, Nitrite, Vinyl Chloride, Viruses 

Wastewater Treatment Facilities/Discharge locations (incl. land disposal 

and underground injection of sludge) 

Cadmium, Coliform, Cryptosporidium, cis-1,2-Dichloroethylene, trans-1,2-Dichloroethylene, 

Dichloromethane or Methylene Chloride, Fluoride, Giardia Lamblia, Lead, Mercury, Nitrate, 

Nitrite, Tetrachloroethylene or Perchlorethylene (Perc) Selenium, Sulfate, Trichloroethylene 

(TCE), Vinyl Chloride, Viruses 

Agricultural / rural 

Auction Lots/Boarding Stables Coliform, Cryptosporidium, Giardia Lamblia, Nitrate, Nitrite, Sulfate, Viruses 

Animal Feeding Operations/ Confined 

Animal Feeding Operations 

Coliform, Cryptosporidium, Giardia Lamblia, Nitrate, Nitrite, Sulfate, Turbidity, Viruses 

Bird Rookeries/Wildlife feeding /migration zones 

Coliform, Cryptosporidium, Giardia Lamblia, Nitrate , Nitrite , Sulfate, Turbidity, Viruses 

Crops - Irrigated and Non-irrigated Benzene, 2,4-D, Dalapon, Dinoseb, Diquat, Glyphosate, Lindane, Lead, Nitrate, Nitrite , 

Picloram, Simazine, Turbidity 

Dairy operations Coliform, Cryptosporidium, Giardia Lamblia, Nitrate , Nitrite, Sulfate, Turbidity, Viruses 

Drainage Wells, Lagoons and Liquid 

Waste Disposal - Agricultural 

Atrazine, Alachlor, Coliform, Cryptosporidium, Carbofuran, Diquat, Dalapon, Giardia Lamblia, 

Glyphosate, Nitrate, Nitrite, Oxamyl (Vydate), Picloram, Sulfate, Simazine, Vinyl Chloride, 

Viruses 

Managed Forests/Grass Lands Atrazine, Diquat, Glyphosate, Picloram, Simazine, Turbidity 

Pesticide/Fertilizer Storage Facilities Atrazine, Alachlor, Carbofuran, Chlordane, 2,4-D, Diquat, Dalapon, 1,2-Dibromo-3-

Chloropropane or DBCP, Glyphosate, Nitrate, Nitrite, Oxamyl (Vydate), Picloram, Simazine, 

2,4,5-TP (Silvex) 

Rangeland/Grazing lands Coliform, Cryptosporidium, Giardia Lamblia, Nitrate, Nitrite, Sulfate, Turbidity, Viruses 

Residential Wastewater lagoons Atrazine, Alachlor, Carbofuran, Coliform, Cryptosporidium, Diquat, Dalapon, Giardia Lamblia, 

Glyphosate, Nitrate, Nitrite, Oxamyl (Vydate), Picloram, Sulfate, Simazine, Vinyl Chloride, 

Viruses 

Rural Homesteads Atrazine, Alachlor, Carbofuran, Coliform, Cryptosporidium, cis-1,2-Dichloroethylene, trans-1,2-

Dichloroethylene, Diquat, Dalapon, Giardia Lamblia, Glyphosate, Nitrate, Nitrite, Oxamyl 

(Vydate), Picloram, Sulfate, Simazine, Vinyl Chloride, Viruses 

Appendix 2. Potential Sources of Drinking-Water Contamination Index 37
38 Methods Used to Assess the Susceptibility to Contamination of Transient, Non-Community Public Ground-Water Supplies

Appendix 2. Potential Sources of Drinking-Water Contamination Index.—

Continued

[UIC, Underground injection control; Vet, Veterinary; RV, recreational vehicle]

Potential source Contaminant of concern

Miscellaneous sources 

Abandoned drinking water wells (conduits for contamination) 

Atrazine, Alachlor, Coliform, Cryptosporidium, Carbofuran, Diquat, Dalapon, Giardia Lamblia, 

Glyphosate, Dichloromethane or Methylene Chloride, Nitrate, Nitrite, Oxamyl (Vydate), 

Picloram, Simazine, Trichloroethylene (TCE), Turbidity, Vinyl Chloride, Viruses 

Naturally Occurring Arsenic, Asbestos, Barium, Cadmium, Chromium, Coliform, Copper, Cryptosporidium, Fluoride, 

Giardia Lamblia, Iron, Lead, Manganese, Mercury, Nitrate, Nitrite, Radionuclides, Selenium, 

Silver, Sulfate, Viruses, Zinc (Fume or Dust) 

Underground Injection Control (UIC) 

Wells CLASS I - deep injection of 

hazardous and non-hazardous wastes 

into aquifers separated from underground sources of drinking water 

U.S. Environmental Protection Agency (2006a) 

UIC Wells CLASS II deep injection 

wells of fluids associated with oil/gas 

production (for more detailed list of 

sites click here) 

U.S. Environmental Protection Agency (2006b) 

UIC Wells CLASS III re-injection of 

water/steam into mineral formations 

for mineral extraction 

U.S. Environmental Protection Agency (2006c) 

UIC Wells CLASS IV - officially 

banned. Inject hazardous or radioactive waste into or above underground 

sources of drinking water 

U.S. Environmental Protection Agency (2006d) 

UIC Wells Class V (Shallow injection 

wells)

U.S. Environmental Protection Agency (2006e)

Source: U.S. Environmental Protection Agency (2004)
Appendix 3. Concentrations of Nitrate and Thickness of Fine-Grained Geologic 

Materials Above the Well Screen in Indiana

Appendix 3 data are available in an Excel data base spreadsheet and a tab-delimited file for download:

 Tab-delinited URL: http://pubs.usgs.gov/sir/2005/5059/htdocs/Appendix_3.txt

 Excel data base spreadsheet URL: http://pubs.usgs.gov/sir/2005/5059/htdocs/Appendix_3.xls

Appendix 3. Concentrations of Nitrate and Thickness of Fine-Grained Geologic Materials Above the Well Screen in Indiana 39
40 Methods Used to Assess the Susceptibility to Contamination of Transient, Non-Community Public Ground-Water Supplies
Arihood, L.D., and Cohen, D.A.—Methods Used to Assess the Susceptibility to Contamination of Transient, Non-Community Public Ground-Water Supplies in 

Indiana —Scientific Investigations Report 2005–5059

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