EPA816-K-06-004

Office of Water

September 2006

DISCLAIMER

The U.S. Environmental Protection Agency (EPA) prepared this Manual to help you update and enhance your 

source water protection assessment. This document does not impose legally binding requirements on EPA, 

states, tribes, or the regulated community, and it may or may not be applicable to a particular situation 

depending on the circumstances. Updating and/or enhancing a source water protection assessment is 

voluntary. Source Water Protection Partners (public and private individuals/organizations interested in 

protecting source waters) who choose to enhance and/or update assessments, retain the discretion to adopt 

none, any, or all of the approaches described in this document, on a case-by-case basis. EPA may change 

this Manual in the future. To obtain additional copies of this document, contact the Safe Drinking Water 

Hotline at (800) 426-4791.
www.epa.gov/safewater

TABLE OF CONTENTS

1. INTRODUCTION .........................................................................................................................3

A. The Purpose of This Manual.....................................................................................................3

 • Who Is the Biggest Beneficiary of an Updated Assessment? .....................................................4

B. Why Your State Assessment Could Benefit From Updating..........................................................4

 • State Assessments May Contain Limited Data .........................................................................4

 • State Assessments Address Only Most Significant Threats ........................................................4

C. Additional Reasons For Updating/Enhancing Assessments.........................................................4

D. The Role Played by Source Water Protection Partners .................................................................5 

E. Initiating Action and Building Support ......................................................................................5

2. OPPORTUNITIES FOR UPDATING AND ENHANCING ASSESSMENTS WITH 

 LOCAL INFORMATION.............................................................................................................6

A. How Source Water Protection Partners Can Update and Enhance Delineations ...........................6

 • Partners Can Improve Delineation of Ground-Water Supplied Source Water 

 Areas Through a Variety of Methods ...................................................................................6

 • Partners Can Improve Surface-Water Critical-Area Delineation................................................8 

 Arbitrary Radial Distance ..................................................................................................8 

 Stream Time-of-Travel Distance .........................................................................................8 

 Buffer Zones ....................................................................................................................9 

 Time-of-Travel Area ..........................................................................................................9 

 • Partners Can Improve Ground-Water/Surface-Water Conjunctive Delineations .......................10 

B. Reasons to Update and Enhance Contaminant Source Inventories............................................10

 • How States Developed the Contaminant Source Inventory .....................................................10 

 • The Contaminant Source Inventory as an Opportunity to Enhance an Assessment ..................10 

 Limited Inventory ............................................................................................................11 

 Changes With Time........................................................................................................11 

 Emerging, and Other Unregulated, Contaminants ...........................................................11 

 • Contaminant Source Inventory Methods Used by States.........................................................11 

 • Partner Actions to Update/Enhance Contaminant Source Inventories......................................12 

 Supplementing Initial Inventory with Local Data ...............................................................13 

 Adding Information to Existing Data Sources and Obtaining 

 Additional Information From Data Gatherers................................................................13 

 Ascertaining That All Significant Potential Contamination Sources are Identified 

 and Located ...............................................................................................................14 

 Evaluating Implementation and Effectiveness of Existing 

 Protection Strategies ...................................................................................................14 

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How-To Manual: Update and Enhance Your Local Source Water Protection Assessments

 Performing Other Activities .............................................................................................15

 Encouraging Participation of Source Water Protection Partners ..........................................15 

3. UPDATING AND/OR INCORPORATING ADDITIONAL INFORMATION INTO 

 SUSCEPTIBILITY DETERMINATIONS..........................................................................................16

 A. Critical Factors to Consider When Determining the Susceptibility of the Public Water Supply ......16

• Presence of Potential Contaminant Sources and the Impacts of Contaminant

 Characteristics and Management Practices .......................................................................16 

 • Physical Integrity.................................................................................................................17

 • Sensitivity of the Natural Setting...........................................................................................17

 • Presence of Natural Contamination in the Source Water.......................................................17

B. How States Combined These Factors to Arrive at a Susceptibility Determination.........................18

C. The Intra-system and Inter-system Approaches to Susceptibility Determination ..........................18

D. When and How Source Water Protection Partners Can Recalculate/Revise the 

 Susceptibility Determination ................................................................................................19

4. DISSEMINATING ASSESSMENTS TO THE PUBLIC .......................................................................21

5. WHAT PARTNERS CAN DO AFTER THE ASSESSMENT .................................................................22

APPENDIX A: BRIEF DESCRIPTIONS OF METHODS FOR DELINEATING SOURCE 

WATER PROTECTION AREAS FOR PUBLIC WATER SUPPLY WELLS..................................23

APPENDIX B: USING SANITARY SURVEYS TO UPDATE STATE SOURCE 

WATER PROTECTION PROGRAMS ...............................................................................24 

APPENDIX C: WHERE TO FIND SOURCE WATER ASSESSMENTS........................................................31

APPENDIX D: HELPFUL EXAMPLES OF ASSESSMENTS .......................................................................33

APPENDIX E: ACRONYMS ...............................................................................................................33
www.epa.gov/safewater

1 . I N T RO D U C T I O N

1 States that regulate source water and/or wellhead protection generally require periodic review and revision of the protection plans. In 

these states, contact the state implementing agency to ensure that any revision will meet their requirements. In states where source water 

and/or wellhead protection is voluntary, check with the state to determine whether or not supplying them with enhancement results would 

prove useful. Asking the state for technical assistance might be helpful, but Partners need to be aware that the state’s capacity to provide 

it is limited.

Public water system’s no trespassing sign.

This is a general document that is applicable 

across the country. States may have similar documents or information targeted specifically to their 

own Source Water Protection Partners. The contact 

information for the source water assessment and 

protection agency in each state can be found at: 

http://www.epa.gov/safewater/sourcewater 

A. The Purpose of This Manual

This manual is intended to help Source Water 

Protection (SWP) Partners protect the raw sources 

of their drinking water from Potential Contaminant 

Sources (PCSs). (For additional guidance, Source 

Water Protection Partners might also refer to the 

State Source Water Assessment and Protection Programs Guidance [1997 Guidance], EPA 816-R-97-

009; (http://www.epa.gov/safewater/

sourcewater/assessmentguidance). 

Source Water Protection Partners involved in SWP 

include: community leaders, local officials, localagency and public water supply personnel, community-based environmental groups, watershed 

and public organizations, farmers and businesses, 

concerned citizens and state source water protection implementing agencies. This manual provides 

the reasons for updating your state’s Source Water 

assessment, explains how Partners are major players, and describes opportunities for enhancing/updating your state’s assessment1 with:

• More accurate delineations.

• Contaminant Source Inventories (CSIs) 

updated with local information. 

• Modified or recalculated Susceptibility 

Determinations (SDs). 

Information collected and analyzed by states across 

the country through source water assessments 

(“assessments”), are used to help determine priorities needed to protect local drinking-water sources 

of each Public Water Supply (PWS). The assessments, performed under the Safe Drinking Water 

Act section 1453, were required as a one-time 

effort. The information from a local assessment 

can be used by SWP Partners to develop or expand 

activities to prevent contamination of local sources 

of drinking water.

States were required to conduct an assessment 

for the source of supply for every PWS - from the 

roadside diner’s well to the river providing drinking 

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How-To Manual: Update and Enhance Your Local Source Water Protection Assessments

Economic savings resulting from such flexibility could benefit many public water 

systems, particularly if the assessments are 

updated periodically.

There are hundreds of sources that could 

potentially contaminate a community’s 

water supplies, resulting in considerable 

expense to the community. For instance, 

PCSs could include: an accidental release 

from a town’s sewage treatment plant upstream, a leaky backyard heating-oil tank, 

the rupture of a gasoline pipeline near a 

community well, or a small hog farm discharging excess waste to a local stream. 

water for a major metropolitan area. Most assessments have been completed. However, because 

states had a limited timeframe, baseline assessments, which states completed for all community 

water systems using readily available information, 

might be improved by additional data. In addition, 

there may have been changes in land uses or other 

activities that would affect the baseline assessment. 

In such cases, opportunities exist for SWP Partners 

to add local data to the state’s initial assessment.

Who Is the Biggest Beneficiary of an Updated 

Assessment?

The more comprehensive and current an assessment, the more it is likely to be useful for providing 

a basis for regulatory flexibility under current or 

planned rules under the Safe Drinking Water Act 

and state laws (e.g., waivers or alternative monitoring schedules). 

B. Why Your State Assessment 

Could Benefit From Updating

Your state was probably only able to complete a 

baseline assessment for all community water 

systems. These assessments may be short of information, particularly local data, and do not reflect 

changes in land use or other activities that may 

have occurred since the assessments were completed. This is because your state, like all states, 

had only 3 1/2 years to complete assessments for all 

of its PWSs. 

State Assessments May Contain Limited Data

Many states had hundreds or thousands of assessments to complete and needed to budget time and 

resources in order to meet the required deadline. 

Most states relied primarily on readily available information. Depending on the state’s priorities and 

resources, the depth of detail and technical complexity of the assessments varied across the Nation 

and within some states. For example, according 

to New York’s priority-setting process, assessments 

for systems that serve large populations and those 

that have existing contamination problems were 

conducted in greater detail than those for other 

systems. 

Other states used less rigorous methods for conducting assessments for small or transient systems, 

or for systems in certain hydrogeologic settings 

such as confined aquifers. Where states asked 

water systems or local government agencies to 

conduct all or part of the assessments, the level of 

detail and thoroughness likely varied depending 

on the local resources and expertise available to 

complete the work. 

State Assessments Address Only Most 

Significant Threats

Although state and federal regulations focus on the 

large, obvious water dischargers, sometimes it’s 

the less obvious unregulated contamination sources 

that cause a community’s water supply to become 

contaminated. Unregulated sources such as contaminated runoff from communities and agricultural activities can also transport contaminants to a 

water source. 

C. Additional Reasons For 

Updating/Enhancing 

Assessments

Updating or enhancing assessments is a natural 

next step because:

• Many states adopted an iterative approach 

to source water assessment and protection; 

promoting local enhancement/updating of 

assessments supports both iterative state 

source water assessment plans and source 

water protection implementation.

• Completed assessments provide, for this first 

time in many cases, a platform from which 

to work.

• Time constraints associated with initial deadlines have passed. 

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• Land use activities, and hence potential contaminant sources, change over time. 

• Additional data sources may now be available to support enhancements and updates.

Enhanced/updated assessments can: 

“Ground truth” initial-assessment results, 

especially if they are not consistent with local knowledge or do not reflect site-specific 

information. 

• Help define priorities for protection activities. 

• Result in improved or maintained high, rawwater quality and its attendant cost savings.

• Provide greater accuracy and facilitate implementation of protection measures. 

D. The Role Played by Source 

Water Protection Partners 

EPA encourages Partners to build on the core 

program developed by the state, by updating and 

enhancing the initial assessment with additional 

local data and/or more rigorous approaches to 

make assessments meaningful tools for protection 

management.

Partners can gather local data on PCSs that may 

not be available to state agencies, collect additional information on PCSs that may threaten the water 

supply, create a comprehensive inventory of potential threats to the water supply, and create a more 

•

detailed and thorough local assessment that can 

be used to more accurately identify priority protection needs. Once these priorities are identified, 

SWP Partners can begin working on a balanced 

and justifiable plan to manage threats and prevent 

contamination of the drinking-water supply. 

The initial assessment may have provided recommendations for actions that SWP Partners could 

take to protect the source water. In such cases, the 

assessment may be enhanced as recommended, 

to help community leaders begin to plan and 

implement a protection program based on the 

assessment’s findings, and to adapt the protection 

program over time. 

E. Initiating Action and Building 

Support

In some cases, community leaders will take the 

initial action and engage other SWP Partners in 

enhancing/updating assessments. In other cases, 

the initial action will be taken by local organizations such as a watershed group or the League of 

Women Voters. 

Broad support for protecting the drinking-water 

source can be built if a wide cross-section of SWP 

Partners is engaged in the assessment and protection process. 

When a broad array of local officials, youth and 

community groups, businesses and other interested community members become informed and 

engaged in the process of protecting the water 

source, obstacles can be overcome and a stage set 

for the implementation of a protection program. A 

safe and reliable source of drinking water is important to everyone, and creative and cooperative 

approaches can be developed once community 

leaders join other SWP Partners to work together to 

periodically enhance and update assessments.

Public involvement educates individuals 

about how their own actions may impact the 

community’s water source. 

Source Water Protection Partners inputting locations of potential 

contaminant sources into a computer. Photo by Stephen Ausmus; 

U.S. Department of Agriculture, Agricultural Research Service

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How-To Manual: Update and Enhance Your Local Source Water Protection Assessments

This section is intended to help Source Water 

Protection (SWP) Partners look closely at the methods and techniques used in conducting their local 

assessment and to help determine if the assessment 

should be updated or if new information is available that could enhance the detail and accuracy of 

the current assessment.

The actual work of enhancing/updating assessments can be performed not only by public-watersupply (PWS) and state/local-government employees, but also by other Partners. For example, with 

training, volunteers such as local civic organizations, youth groups or retirees can provide valuable 

assistance in gathering and consolidating local 

data to enhance the assessment. Communities 

may be able to reach an agreement with the state 

implementing agency to receive training on performing the elements of interest in the assessment 

enhancement/updating process. Although Partners 

might ask the state for technical assistance, they 

should be aware that the state’s capacity to provide 

it is limited.

A. How Source Water Protection 

Partners Can Update and 

Enhance Delineations

Partners Can Improve Delineation of 

Ground-Water Supplied Source Water 

Areas Through a Variety of Methods

The states employed a variety of methods for 

delineating the source water areas (SWAs) of PWS 

wells. Some of these methods are more scientifically based than others, and in many communities 

opportunities exist to refine the initial delineation2. Partners should consider employing a more 

sophisticated, ground-water delineation method, 

particularly when (1) a more accurately delineated 

SWA is desired in order to target or justify SWP 

measures and/or (2) the well is located in a karst, 

or other hydrogeologically complex, setting and 

the initial delineation method was not hydrogeologic mapping. All methods, except arbitrary fixed 

radius and hydrogeologic mapping, can provide a 

ground-water travel-time distance to a well.

The order of increasing accuracy and sophistication 

of the methods is as follows:

• Arbitrary fixed radius

• Calculated fixed radius

• Fixed variable shapes

• Analytical methods (such as the uniform flow 

equation)

• Hydrogeologic mapping

• Numerical flow or flow-and-transport computer models

Brief descriptions of these methods are provided in 

Appendix A.

Two methods could be combined. For example, the 

boundary selected could be the closer of the hydrogeologic boundary and the 10-year ground-water 

travel-time boundary determined by flow modeling. 

Partners might also want to consider expanding the 

SWA by selecting a larger fixed radius or a longer 

ground-water travel time to the well.

2 . O P P O RT U N I T I E S F O R U P D AT I N G A N D 

E N H A N C I N G A S S E S S M E N TS W I T H LO C A L 

I N F O R M AT I O N

2 Partners are advised to contact the appropriate municipal, county and, where appropriate, state authorities, when enhanced or updated 

delineation yields revised source watch protection area boundaries.

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Fixed-radius methods tend to overprotect a well in 

the direction of ground-water flow and underprotect in the direction opposite to ground-water flow. 

Communities/PWSs could upgrade their delineation 

approach and, where it would add accuracy, take 

advantage of the user-friendly Wellhead Analytical 

Element Model (WhAEM), or other computer-modeling programs.

Enhancing ground-water delineations requires 

more technical expertise than enhancement of 

other aspects of the assessment.

Again, in states where Source Water Protection and/

or Wellhead Protection are required, state regulations 

generally have requirements for periodic review and 

revision of the protection plans. In these states, Partners should consult with the implementing agency to 

ensure that enhanced delineations will meet state requirements. In states where Source Water Protection 

and/or Wellhead Protection are voluntary, Partners 

may check with the state early in the enhancement 

process, and provide results if the state would like to 

have them. The state implementing agency may be 

able to provide information on appropriate delineation methods, or information on why the original 

method was chosen. In general, simpler methods 

had been selected because of the lack of information 

necessary to perform more sophisticated analyses, 

and because of the lack of funding to collect additional information and support technical staffers who 

could perform more complex analyses.

The use of any delineation method except the arbitrary fixed radius requires some hydrogeologic 

knowledge. (see Appendix A) However, moving up 

from the arbitrary fixed radius to the calculated fixed 

radius method is generally not costly and needs only 

minimal input from a hydrogeologic expert. Thus, 

for communities in those states that have employed 

the arbitrary fixed radius method, recalculating the 

SWA with the calculated fixed radius method may 

be fairly straightforward. The fixed variable shapes 

method likely will require a moderate amount of input from a hydrogeologic expert, who will be needed 

to supply the ground-water flow directions and the 

values of the hydrogeologic parameters.

Hydrogeologic mapping can include improved 

information about natural sensitivity and/or about 

underground barriers to ground-water flow. Such 

information needs should require input from 

technical experts. Incorporating sensitivity and/or 

barrier information likely will increase the accuracy 

and protectiveness of the delineation of the SWA 

for a well. Partners have the opportunity to delineate entire aquifer outcrop areas as sensitive areas 

and are encouraged to identify karst features, such 

as sinkholes, as potential contaminant sources 

(PCSs). 

The Environmental Protection Agency’s WhAEM numerical flow computer model has been modified to 

be more user-friendly. Some states have used other 

sophisticated computer models to perform delineations. The use of any computer model requires the 

services of a technical expert; simple-to-use models require, at a minimum, expert opinion on flow 

boundaries and parameter values. Upgrading to 

computer modeling with all but the simplest-to-use 

models is probably realistic only for moderate to 

large PWSs. 

It could become costly for a community to hire outside experts to enhance a delineation, depending 

on the rates charged and the method to be used. 

However, there are several sources of potential assistance available; some may provide low-cost or 

free services to communities. Technical assistance 

resources might include:

• State SWP implementing agency (http://www.

epa.gov/safewater/sourcewater). 

• EPA regional office (http://www.epa.gov/

safewater/sourcewater). 

• US Geological Survey District Office (http://

interactive2.usgs.gov/contact_us/index.asp).

• US Department of Agriculture Cooperative 

Extension System Office (http://www.csrees.

usda.gov/Extension/index.html).

• State geological survey; the simplest link is 

through the Association of American State 

Geologists (http://www.gsa.state.al.us/).

• State Rural Water Association wellhead and 

source water programs (http://www.nrwa.

org/sa.htm).

• Local health department.

If Partners revise a delineation, then they 

likely will need to revise the contaminant 

source inventory and recalculate the results 

of the susceptibility determination.

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How-To Manual: Update and Enhance Your Local Source Water Protection Assessments

• Professors or graduate students at a local 

college or university in the departments of 

Environmental Studies, Geology/Hydrology, 

Engineering (civil, hydrologic or 

environmental).

• Hydrogeologists, engineers or environmental 

professionals in the community.

• Hydrogeologic and environmental consulting 

firms.

Partners Can Improve Surface-Water 

Critical-Area Delineation

All states delineated the SWA as the entire watershed upstream of a surface-water intake up to the 

watershed boundary or to the state boundary, if it 

is closer. Because some watersheds are very large, 

states frequently segmented them, identifying a 

smaller “critical area” for higher-priority assessment. Critical areas were used solely to determine 

the intensity of the contaminant source inventory 

(CSI) and as one of many factors in determining 

susceptibility.

A more detailed CSI was usually conducted in the 

critical area rather than in the rest of the watershed, because contaminants released in this area 

are more likely to reach and contaminate surface 

source water. Areas outside the critical area were 

inventoried for larger potential contaminant sources, those within the critical area for all potential 

contaminant sources, and the results were analyzed 

for susceptibility. 

States generally selected one of four general 

types of critical-area delineation approaches: (1) 

a stream time-of-travel distance upstream of an 

intake; (2) an area defined by an arbitrary radial 

distance either around, or uphill of, the intake; (3) 

a buffer-zone setback, and (4) a stream time-oftravel area. Some states used a combination of 

these delineation approaches. 

As examples, some states have not included buffer 

zones along upstream tributaries and, perhaps with 

rare exception, states have not incorporated land 

area into a stream time-of-travel delineation. Additionally, actual monitoring data may indicate that 

sources of contaminants in surface waters in the 

SWA may lie outside of the current critical area. 

Partners might be particularly interested in expanding stream buffers (1) where buffers only extend a 

few hours stream travel time upstream of an intake, 

or (2) along streams where the selected delineation method was a stream travel-time distance and, 

hence, no buffer exists.

Partners should consider expanding existing critical 

areas to include as much of the watershed as possible in order to expand the CSI. This will facilitate 

development of better protection programs.

Arbitrary Radial Distance

The area that is defined with the arbitrary radial 

distance method is bounded by a circle centered at 

the water supply intake, or by the upstream half of 

that circle. The radius of the circle is defined arbitrarily or by factors unrelated to hydrology.

Stream Time-of-Travel Distance

The stream time-of-travel distance approach 

defines the length of the stream, above an intake, 

through which a particle of water will travel in a 

state-defined time period. (Some states use this 

approach specifically for transportation routes 

and other facilities with the potential to spill contaminants directly into a stream. This approach is 

particularly useful for setting up contingency plans 

with local law enforcement and with facility manThe primary reason to update the delineation of a critical area is that the delineated 

area was not large enough to incorporate 

significant potential contaminant sources. 

Reservoir catchment area. Photo by Tim McCabe, USDA Natural 

Resources Conservation Service.

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agers.) However, unless combined with a buffer 

zone, this approach does not have an associated 

land area and so, no preferentially intensive CSI is 

performed. 

Buffer Zones 

Partners may want to enhance SWAs by expanding buffer zones to include more of the PCSs that 

are near the source water. Expanded buffers are 

helpful if Partners believe that the original buffers 

exclude PCSs that could contaminate the source 

water. Because overland travel time after a moderate to heavy rain can be quite short, contaminants 

released from PCSs could quickly reach the sourcewater stream or body. Although the United States 

Department of Agriculture has technical assistance 

for calculating buffer width to help protect surface 

water from nutrients, there is no hydrologic basis for other buffer setbacks or for time-of-travel 

distance upstream. However, as a general rule of 

thumb, “bigger is better”. When considering expansion of buffers, Partners should consider factors 

such as: costs, availability of staff and/or volunteers, the hydrogeologic/hydrologic setting, and the 

CSI that will be performed. 

Many states delineated buffer zones (“setbacks”) 

along stream banks, upstream of PWS intakes, to 

designate critical areas. Many of these states chose 

to use the minimum 1,000 ft width approvable by 

EPA. The upstream extent of these buffers varies by 

state, as does whether or not upstream tributaries 

also have buffers delineated. Some states define 

the upstream limit of the setback by employing a 

fixed distance or a state-selected, average-streamflow travel time, such as 5 hours, perhaps associated with the response time needed to respond to a 

spill into the stream. 

Time-of-Travel Area

Source Water Protection Partners may want to 

enhance SWAs by expanding them to the area 

defined by the Time-of-Travel Area approach. This 

creative approach is based on a pre-selected travel 

time, applied to not only the flow of the stream, but 

also to the travel time of overland flow. States can 

use any travel time that they choose, such as the 

time needed to respond to a spill. This approach 

leads to a “leaf-shaped” region, whose boundary 

contains all the area that drains to an intake within 

the state-specified travel time. Figure 1 depicts an 

area defined by a 4-hour stream travel time. A 

very similar approach is used by the state of 

Nebraska. 

A modification of this method, shown in Figure 2, 

yields a larger, more easily calculated SWA. Figure 

2 depicts an area defined by the distance traveled 

in 4 hours, ending at the intake, by water in the 

fastest flowing stream. The 4-hour distance is applied not only to the fastest flowing stream, but also 

to all other streams’ lengths and overland travel 

paths ending at the water supply intake.

Figure 1: Diagram of area defined by the 4-hour stream travel 

 time.

 Figure 2: Area defined by 4-hour travel time of fastest stream or 

 tributary.

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How-To Manual: Update and Enhance Your Local Source Water Protection Assessments

Partners Can Improve Ground-Water/SurfaceWater Conjunctive Delineations

In many places, water moves routinely between 

a surface-water source such as a river, stream or 

lake, and the underlying and adjacent ground 

water. Wells that are located within river floodplains often draw part of their water from the 

rivers. Similarly, in many places for at least part of 

the year, much or most of a stream’s flow results 

from ground water that recharges the stream. The 

US Geological Survey estimates that about 40% of 

stream flow nationwide comes from ground water 

discharging into streams.

“Conjunctive delineation” was recommended in 

the 1997 Guidance for PWS wells withdrawing 

from where the quality of a drinking-water source 

is strongly influenced by both ground-water and 

surface-water sources. Such a delineation includes 

both the surface-water and the ground-water areas 

that could contribute water and pollutants to the 

drinking-water supply. Conjunctive delineation 

results in a delineation of both a SWA for the well 

and the watershed area upstream of where the 

well’s SWA intersects the stream. An inventory of 

PCSs should be conducted in both the surface-water and the ground-water areas. Remember that 

changing the delineated area of a well may also 

alter the conjunctively delineated SWA. 

If a state did not initially perform a conjunctive 

delineation, and there is a reason to believe that 

a PWS well is influenced by both ground water 

and surface water (for example, if surface-water 

contaminants are present in a ground-water supply), SWP Partners should consider discussing the 

possibility of conducting a conjunctive delineation. As stated earlier, states where Source Water 

and/or Wellhead Protection are required under 

state regulations generally have requirements for 

periodic review and revision of protection plans. In 

these states, SWP Partners should ensure that their 

process meets state requirements. In states where 

Source Water and/or Wellhead Protection are 

voluntary, it would be a courtesy to check with the 

state and provide the results of the enhancement, if 

the state has the capacity to use it. 

B. Reasons to Update and Enhance 

Contaminant Source Inventories

How States Developed the Contaminant 

Source Inventory

As with other parts of the Source Water Protection 

program, states were given flexibility in designing the CSI methods to be used. This resulted in a 

variety of inventory methods in the SWP programs 

among different states. Also, a state may have 

used a variety of inventory methods, each method 

being based on the size or type of water system. 

For instance, the inventory for a well serving a 

roadside public drinking fountain might consist of 

only the PCSs of such contaminants as bacteria 

and nitrates, that is, those contaminants that could 

make someone sick with a limited consumption 

of the water. By comparison, the inventory for a 

water system serving a metropolitan area would 

include all types of regulated drinking water contaminants, and the inventory could extend up to, 

or perhaps into, upstream states. Many states 

conducted inventories primarily using databases of 

regulated activities, supplemented with additional 

information such as land use. States may or may 

not have included local information in the initial 

effort, depending on such factors as availability, local participation, and state resources to gather this 

information. 

States included in their inventories potential sources 

of chemicals regulated under the Safe Drinking 

Water Act (contaminants with a maximum contaminant level, contaminants regulated under the Enhanced Surface Water Treatment Rule, and the microorganism Cryptosporidium). In addition, states 

were invited to include other contaminants that are 

not federally regulated, but which the state had determined may present a threat to public health. For 

instance, New York included pathogenic viruses as 

a contaminant of concern in its assessments, even 

though the federal government does not currently 

regulate them. 

The Contaminant Source Inventory as an 

Opportunity to Enhance an Assessment

The CSI is an opportunity for SWP Partners to 

enhance an assessment with local information. 

EPA encourages Partners to invest the time and 

resources in contributing additional information 

to the inventory, since this will ensure that the list 

of PCSs is as comprehensive as possible. For 

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example, information on abandoned waste sites, 

industrial septic tanks, home fuel oil tanks, small 

livestock operations, golf courses and other land 

uses or activities that could release pollutants to the 

water supply, could be added to the initial inventory 

through local efforts. Another approach to identifying contaminant sources is performing, or identifying studies that have performed, reverse-tracking 

computer modeling of contaminants causing drinking water violations.

In addition, local involvement can greatly increase 

public knowledge of the resource and generate 

support for activities to protect the community’s 

source water. Lastly, if new wells or intakes have 

come online, or wells/intakes have been relocated, 

a complete source water assessment should be 

performed.

There are three primary reasons for updating and 

enhancing contaminant source inventories: limited 

inventory; changes with time; and emerging, and 

other unregulated, contaminants. 

Limited Inventory

To enhance a limited inventory: because of the 

limited time available to states, many chose to 

perform limited CSIs. Even those states that performed more extensive inventories may have PCSs 

that were not identified or field-verified, or that 

came into existence after the initial assessment was 

completed.

Source Water Protection Partners particularly should 

consider enhancing the initial inventory if: 

• The inventory is based solely on information 

from state or federal databases (no local data 

were used).

• Primary categories of PCSs are not inventoried.

• Locations of PCSs are not verified in the field. 

• Specific PCSs are not identified, only the PCS 

category is mentioned. 

• The community has additional information 

and data to enhance the inventory. 

• The hydrogeologic setting is sensitive/vulnerable.

Changes With Time

To reflect changes with time: EPA encourages SWP 

Partners to regularly update CSIs to reflect changing land use and activities, and/or PCSs introduced 

into the SWA by virtue of a change in the delineated boundary of a SWA for a well, or a critical area 

for a surface-water-supplied intake. 

Emerging, and Other Unregulated, Contaminants

Partners might want to perform a CSI to address 

emerging contaminants. Some system managers are becoming particularly concerned about 

pharmaceuticals, chlorophyll A and caffeine. When 

these are found in drinking water, it is likely that 

they have come from an upstream waste treatment 

plant. Water system managers should be alert to 

this emerging issue. In addition, some constituents 

on the Contaminant Candidate List have risen to 

national attention; these, too, might be considered when updating/enhancing assessments. EPA 

recommends that all relevant unregulated contaminants be considered in an assessment update.

Contaminant Source Inventory Methods Used 

by States

Because states used an array of methods to conduct their CSI, the inventories varied considerably 

in level of detail and comprehensiveness. Most 

states conducted database searches of regulated 

facilities as an initial step in the inventory. In some 

Sign stating change in land use from farming to commercial. Photo 

by Lynn Betts, USDA Natural Resources Conservation Service.

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How-To Manual: Update and Enhance Your Local Source Water Protection Assessments

states, such database searches comprised the 

entire inventory. In other states, a more detailed 

investigation on the ground for some or all PWSs, 

revealed considerable information that may not 

have been found in the databases. If a state relied 

mostly on regulatory and land use databases, it 

may have missed many smaller unregulated PCSs 

(such as residential septic tanks, underground storage tanks, storm-sewer outfalls, pesticide mixing 

areas, etc.) that could severely impact drinking-water sources. Source Water Protection Partners now 

have the opportunity to update and enhance their 

inventories. 

Methods used by states to inventory PCSs in their 

approved plan include, but are not limited to:

• Database searches of regulated facilities 

(those facilities with Clean Water Act discharge permits, with hazardous- or solidwaste permits, underground storage tanks, 

etc.) on state and federal databases.

• Additional/updated databases of PCSs available from state and/or local health departments and from environmental agencies.

• Land use maps of the delineated area (agricultural, high intensity to low intensity residential, industrial, etc.) usually created at the 

state or local levels.

• Information from sanitary surveys and other 

local health- or environmental-agency data.

• On-site field inspections in the delineated 

areas.

• Aerial photographs.

• Local tax and land-ownership maps.

Including one or more of these methods/tools 

during assessment enhancement could be helpful 

in states where these methods/tools had not been 

used in the initial assessments.

States generally chose to perform either inventories 

of contaminant sources, or inventories of specific 

contaminants. Examples of the former category 

are gas stations, commercial laundries, and photo 

developers. In contrast, examples of the latter 

include Fecal Coliform, Triazine, and paint thinner. 

The 1997 Guidance presents a “cross walk” listing 

potential contaminants within specific PCS types. 

Some state inventories were developed, at least 

in part, by cross-referencing to either match facility/land use type with suites of contaminants, or the 

specific contaminants were cross-referenced with 

specific land uses/facilities. Where it is possible 

to do so with reasonable resources, SWP Partners 

might want to consider enhancing an assessment 

by ground-truthing for the presence of the actual 

contaminants of concern at the inventoried PCS 

locations. Partners could prioritize ground-truthing 

efforts by identifying those PCSs, such as railroad 

yards, most likely to have a very wide variety of 

contaminants not captured in the 1997 Guidance’s 

cross walk.

Partner Actions to Update/Enhance 

Contaminant Source Inventories

Source Water Protection Partners may take any of a 

variety of actions (some of which are listed below) 

to enhance their CSI, if an enhanced or updated 

inventory is considered to be beneficial. 

Partners may choose to undertake just one of these 

activities, or conduct several at once or sequentially over time. Most require little or no financial 

resources, but all require an investment of time by 

community employees or volunteers. These activities include: 

Complete inventories are important, because 

unidentified potential contaminant sources 

can endanger public water supplies.

Examples of potential contaminant sources sometimes missed in 

initial source water assessments.

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Supplementing Initial Inventory with Local Data

• Convene a community meeting in the assessment area to obtain public input on PCSs.

• Conduct a more detailed inventory by walking or driving through SWAs to locate additional PCSs.

• Review the PWS’s Consumer Confidence 

Report.

• Look for other hidden routes of potential 

pollution reaching the drinking water supply 

(infiltration of urban runoff to ground water, 

unused private wells or abandoned natural 

gas wells providing a direct conduit to ground 

water, illegal hookups of sewer lines to storm 

drains, etc.). 

• Identify wells under the influence of surface 

water that were not previously identified as 

such.

• Verify that the database information on regulated facilities and land uses is complete and 

accurate.

• Investigate local interest in obtaining the help 

of a source water or wellhead protection 

specialist from the state affiliate office of the 

National Rural Water Association to conduct 

a detailed inventory as part of a protection 

plan for the community. 

• Work through sanitary survey technicians to 

have well/intake problems and additional 

PCSs identified (see Appendix B).

• Obtain information from relevant EPA reports 

and databases: (1) the National Water Quality Inventory “305(b) report” (http://www.

epa.gov/305b/2000report/ or contact the 

state agency; also see http://www.epa.gov/

waters/305b/index.html); (2) the 303(d) list 

of impaired waters for the state (http://www.

epa.gov/owow/tmdl/); (3) EnviroMapper 

(http://maps.epa.gov/enviromapper), which 

provides locations of, among other data 

elements, selected types of PCSs and their 

locations; (4) EPA’s list of Potential Contaminant Source Inventory Tools (http://www.epa.

gov/safewater/mcl.html#mcls); and (5) EPA’s 

list of watershed groups (http://www.epa.gov/

adopt/network.html).

• Access the state geological survey website 

and the US Geological Survey website (http://

www.usgs.gov) to determine if water-quality data, documents and/or reports exist that 

include the SWA. 

• Overlay locations of PCSs with ownership 

information to determine responsibility for 

on-site management. 

• Contact facilities identified as PCSs to verify 

the CSI information.

Adding Information to Existing Data Sources and 

Obtaining Additional Information From Data 

Gatherers

• Add new types of data to existing data sources to make these sources more valuable for 

updating and enhancing source water assessments. For example, a tax map showing the 

presence of commercial establishments could 

be enhanced to indicate parcels occupied by 

specific businesses, and therefore, by implication, PCSs, such as gas stations, dry cleaners, 

etc.

• Local or state government employees who 

regularly visit sites located within SWAs could 

report new PCSs. (Some training likely would 

be helpful, but this training could be very 

basic. In addition, new or increasingly lowerpriced hand-held tools, for example, personal data assistants and global positioning 

systems, can expedite the process of precisely 

locating and reporting information about 

points of interest.)

Encouraging broad participation of Partners 

in contaminant source inventories’ updates/

enhancements can lead to a wide range of 

people bringing the skills and energy 

needed to complete the effort. 

Source Water Protection Partners convene community members 

to obtain public input.

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How-To Manual: Update and Enhance Your Local Source Water Protection Assessments

Ascertaining That All Significant Potential 

Contamination Sources are Identified and Located

• Verify that the locations of PCSs from the 

initial inventory are accurate.

• Map the locations of individual PCSs on local 

large-scale maps to assist in prioritizing PCS 

impacts on the source water.

• Work with state and local agencies to ensure 

that PCS databases are updated to show improved or updated information (for example, 

add locally inventoried Class V wells to the 

state’s Underground Injection Control Class V 

inventory).

Evaluating Implementation and Effectiveness of 

Existing Protection Strategies

• Perform interviews, owner surveys, tours of 

facilities, examinations of facility regulatory 

permits, expedited inspections, identifications 

and inventories of Best Management Practices 

in place, etc., in order to determine if there 

already are active pollution-prevention or 

management efforts that could prevent the 

release of PCS pollutants to the source water.

• Review compliance records of identified PCSs. 

• Look at permit and monitoring data from 

facilities that discharge wastewater to see the 

types, qualities and quantities of drinkingwater contaminants that are released to the 

source water.

• Obtain local other-than-PCS information 

(such as land-use descriptions, and state and 

federal land management agency management prescriptions). 

Field confirmation of the location of a septic system

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Performing Other Activities 

• Update the initial inventory at regular intervals (every 3 or 5 years, etc.) to address new 

or discontinued land uses or activities. 

• Determine if new PCSs added through local 

information-collection activities change the 

priorities identified in the initial assessment 

(see next section for information on updating 

the susceptibility determination).

• Check with state and federal agencies to 

determine if new data have, or access to 

existing data has, become available since the 

initial assessment was done.

• Inform and involve many local Partners to 

help in enhancing the initial assessment in a 

variety of ways. All segments of the community should be involved in order to create an 

effective program.

• Review the following: local and state landuse restrictions, comprehensive planning 

requirements, and permitting requirements. 

Update them to include specific considerations of drinking-water quality impacts.

Encouraging Participation of Source Water 

Protection Partners

Examples of local people and organizations that 

can collect and compile information on past and 

present PCSs include:

• Local public works or water system employees

• Local Board of Health, Planning Board or 

Conservation Commission members or staff

• Scout troops

 • Retired citizens and their organizations (for 

example, the Retired and Senior Volunteer 

Program)

 • Civic groups (Lions’ Club, League of Women 

Voters, etc.)

 • Neighborhood associations

 • Environmental groups and watershed groups

 • Building inspectors

 • Local businesses and industry

 • Other interested residents

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How-To Manual: Update and Enhance Your Local Source Water Protection Assessments

A. Critical Factors to Consider 

When Determining the 

Susceptibility of the Public 

Water Supply

The susceptibility determination (SD) describes how 

susceptible the public water supply PWS is (1) to 

contamination from the identified potential contaminant sources (PCSs), or (2) to particular contaminants that could be released from those PCSs. The 

1997 Guidance recommended that states consider 

and integrate four critical factors in their SD processes:

• The presence of PCSs (from the inventory), 

and the likelihood that contaminants will be 

released from those contamination sources 

(due to management practices and the nature 

of the contaminant).

• The physical integrity of the well or intake 

(How likely is it that contaminants can enter 

the drinking water system through physical 

breaks or cracks in the well or the pipeline 

connecting the well or intake to the public 

water supply [PWS] facility?).

• The sensitivity of the natural setting (the 

degree and amount of protection afforded 

by the natural hydrogeologic and hydrologic 

setting).

• The presence of existing or likely contamination in the source water.

Presence of Potential Contaminant Sources 

and the Impacts of Contaminant 

Characteristics and Management Practices

The contaminant source inventory provides a list 

of PCSs within the source water area. Evaluation 

of the likelihood of contaminants from the PCSs 

reaching the source water will require that Source 

Water Protection (SWP) Partners develop a process 

to periodically evaluate the likelihood that a contaminant will escape from its containment. The 

process can consist of maintaining and reviewing 

records from scheduled inspections; developing, 

distributing and possibly reviewing the responses 

to, a checklist mailed to PCS owners/operators; 

and/or employing any other vehicle that Partners 

view as protective. The process should incorporate obtaining information on the nature of the 

PCSs themselves, the nature of the contaminants 

3 . U P D AT I N G A N D / O R I N CO R P O R AT I N G 

A D D I T I O N A L I N F O R M AT I O N I N TO 

S U S C E P T I B I L I T Y D E T E R M I N AT I O N S

Source river to a public water supply.

The susceptibility determination is the final 

result of a local source water assessment. 

16
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contained within the PCSs, and the diligence and 

training of the PCS owners/operators. 

Physical Integrity 

The large number of PWSs and the relatively short 

time frame for submitting assessments led, for the 

most part, to states making assumptions based on 

age or similar factors related to the physical integrity of wells, intakes and the conduits connecting 

them to the PWS facility. An updating/enhancement effort provides an opportunity for Partners 

to take a closer look and reconsider the initial 

assumption. Sanitary surveys provide a means of 

evaluating the condition of a well and its likelihood 

of being impacted by overland transport of contaminants. Well integrity tests can be performed 

but are costly, and may only be warranted if a PWS 

owner/operator suspects a problem with the well 

itself. The concern over the physical integrity of an 

intake is, more precisely, a concern regarding the 

integrity of the entire pipeline from the source 

water‘s point of entry into the intake to its point of 

entry into the facility.

All above-ground portions of the intake/well-topipeline-to-facility conduit may already be regularly 

inspected. However, the buried portion is more 

problematic and probably more costly to inspect. 

Depending on the nature of the pipeline and the 

flow within it, remote techniques may be available 

to evaluate the integrity of the buried pipeline. If 

a PWS owner/operator has a reason to suspect 

that breaches have occurred in the conduit (e.g., 

exposure to a natural or man-made event such as 

an earthquake, landslide or explosion) the cost of 

remotely inspecting the conduit is likely justified, 

particularly if water-quality monitoring indicates a 

post-event degradation in water quality.

Sensitivity of the Natural Setting

States addressed hydrogeologic sensitivity in their 

initial assessment. However, natural and human 

forces can modify hydrogeologic sensitivity, although it is relatively stable. For example, if the 

confining layer that provides an aquifer with natural protection from pollutants has been compromised by forces such as earthquakes or by human 

activities such as well drilling or blasting for roads, 

the sensitivity of the aquifer would have increased. 

Source Water Protection Partners should also 

consider if natural events such as earthquakes and 

landslides may have altered not only the geologic 

protection of an aquifer, but also the effectiveness 

of vegetal cover and/or topographic features.

Presence of Natural Contamination in the 

Source Water

Changes in the quality of source waters are generally related to the presence and management of 

PCSs. However, situations can occur where natural events lead to changes in source-water quality. The most obvious events are landslides and 

flooding. Catastrophic flooding of the Mississippi 

River in the early 1990s led to shallow floodplainaquifer contamination that likely lasted far beyond 

the period of flooding. Chlorination and flushing 

of wells would only have resolved the contamination problem for the area immediately around a 

well and possibly only temporarily. Fire damage 

over extended areas can also change source-water 

quality, not just immediately from burnt material 

washing into surface water and from carbon leaching into the ground water, but also from the loss of 

the protection that is afforded by vegetation and by 

the development of hydrophobic layers that cause 

most rain events to run off rather than infiltrate. 

2001 Mississippi River flood: Locks and dam 5NM Northwest 

of Red Wing, MN along the Mississippi River. Photo by NOAA.

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How-To Manual: Update and Enhance Your Local Source Water Protection Assessments

B. How States Combined These 

Factors to Arrive at a 

Susceptibility Determination

In general, the approach developed by each state 

is fairly complicated; revising it may be beyond the 

abilities of SWP partners, although revision is at the 

discretion of the Partners. Each state developed its 

own system for combining information about (1) 

the delineated area, (2) the contaminant source 

inventory, (3) PCS management and (4) the other 

factors (for example, physical integrity of the well), 

to determine the susceptibility of the raw-water 

source. Many states used multiple steps or a matrix 

to integrate the different factors to arrive at the final 

SD. In states where Source Water and/or Wellhead 

Protection are voluntary, it would be a courtesy to 

check with the state and provide the results of the 

enhancement, if the state has the capacity to use it. 

States where Source Water and/or Wellhead Protection are required under state regulations generally 

have requirements for periodic review and revision 

of the protection plans. In these states, Partners 

should ensure that their process meets state requirements. If the state’s source water assessment 

and protection methodology did not include all four 

elements recommended for a determination, Partners may want to consider revising the SD method 

itself. Similarly, PWSs/communities may take this 

opportunity to include more physical or other factors in their determinations.

C. The Intra-system and 

Inter-system Approaches to 

Susceptibility Determination

The 1997 Guidance presented two types of SDs, intra-system and inter-system. Most states performed 

intra-system determinations, that is, determinations 

in which the PCSs within a particular source water area (SWA) were relatively ranked. Few states 

performed an inter-system determination, which 

would have identified the SWAs that were the most 

susceptible to contamination by PCSs. 

A state’s intra-system approach might take these 

four steps: 

 (1) First, determine the source water’s sensitivity 

based on natural aquifer or watershed characteristics.

 (2) Then combine the sensitivity with information 

on the physical integrity of the well, intake, 

and/or conduit.

 (3) For each PCS, relate the information from 

steps 1 and 2 with information on the stateselected PCS characteristics of concern (e.g., 

volume of discharge, toxicity, etc.) for each 

PCS. 

 (4) Use a consistent process to determine the 

final susceptibility of the PWS to each PCS.

A state’s inter-system approach might take these 

five steps: 

 (1) First, determine the source water’s sensitivity based on natural-aquifer or watershed 

characteristics.

 (2) Then combine the sensitivity with information 

on the physical integrity of the well, intake, 

and/or conduit. 

 (3) Relate the information from steps 1 and 2 

with information on existing contamination 

in the source water and with information on 

the numbers, locations, and characteristics 

(volume of discharge, toxicity of potential 

contaminants, presence of management 

measures, etc.) of the significant PCSs within 

the SWA. Alternately, relate the above information to the specific contaminants within the 

PCSs. 

 (4) Use a consistent process to compute the final 

SD for the PWS. 

 (5) Select and use a criterion to rank order the 

PWSs according to their SDs.

Approved intra-system SD approaches produced at 

least one of the following results: 

• The susceptibility of the PWS to PCSs.

• The susceptibility of the PWS to contamination by particular contaminants or classes of 

contaminants. 

• The overall (e.g., high/medium/low) susceptibility of a PWS to contamination. 

Approved inter-system determinations produce 

some type of relative ranking of the susceptibility to 

contamination of a PWS compared to the susceptibility to contamination of other PWSs in the state. 

EPA recommends enhancing SDs by including both 

intra- and inter-system determinations. 

EPA recommends enhancing assessments 

by including both intra- and inter-system 

determinations. 

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D. When and How Source Water 

Protection Partners Can 

Recalculate/Revise the 

Susceptibility Determination

Sometimes communities and other Partners have 

information that was not readily available at the 

time of the initial assessment. For instance, the 

state’s data may show that a water supply well was 

constructed according to acceptable standards, but 

the community may have local data showing that 

the well’s integrity is not good since contamination 

leaks into the well from the ground surface during heavy rains. Such information could alter the 

susceptibility result. 

The introduction of new PCSs, along with changes 

in the management of existing PCSs, is likely to be 

the most common change in an assessment that 

would prompt a revision of a SD. A new residential development, a permit for a feedlot or a mine, 

the construction of a shopping center with a large 

parking lot, the opening of a gas station or a dry 

cleaner - all these are the types of activities that 

may warrant a revision of the determination. The 

operating history and physical upgrades at a local 

factory could reduce the likelihood that the factory 

would contaminate the water supply, and so may 

also alter protection priorities identified in the assessment. A decision by an owner/operator of one 

or more PCSs to relocate outside the SWA, or outside a delineated critical area within the SWA, may 

also be an occasion to revisit the determination in 

order to decide if the threat to the drinking-water 

supply is thereby reduced and priorities should be 

shifted. 

Aside from the relocation of PCSs within, or their 

introduction into, a SWA, changes in the management of PCSs may call for taking another look at 

the SD. New regulations to ban or restrict certain land uses or operating practices, revisions in 

zoning, the purchase and protection of land for 

environmental purposes, a septic tank inspection 

and maintenance program, new Best Management 

Practices for road or housing construction or stormwater control, the adoption of agricultural Best 

Management Practices for nutrient management, 

control of soil erosion, and integrated pest management are just some of the measures that could 

significantly change the results of the initial SD. 

If an updated contaminant source inventory (CSI) 

is performed and additional PCSs are identified, 

cease or significantly modify operations, or their 

management through protection measures is 

significantly altered or a delineated boundary is 

changed, then the SD will have to be recalculated. 

Intra-system determinations help the public 

water supply to prioritize potential contaminant sources and the inter-system determinations help the state and sub-state areas to 

prioritize public water supplies.

Public water supply well.

Road expansion may add potential sources of contamination.

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How-To Manual: Update and Enhance Your Local Source Water Protection Assessments

Similarly, if the delineation is enhanced or there is 

additional information about SD factors, it is possible that the enhancement or new information will 

lead to a different SD result or clarify protection 

priorities. 

In some cases, a state may have identified a need 

to revise its algorithm, or SWP Partners may choose 

to add an enhancement to the state’s SD method in 

order to meet a specific need. For example, if Partners are interested in land conservation, they might 

choose to use as an enhancement, the method that 

is described in Barten and Ernst’s article, “Land 

Conservation and Watershed Management for 

Source Protection,” in the April 2004 issue of the 

Journal of the American Water Works Association 

(pp.121-135). Barten and Ernst presented a project approach with four interrelated components. 

“First, a “fast track” approach was developed 

to build on the results of [the] S[ource] W[ater] 

A[ssessment] P[rogram]. ... Second, a Geographic 

Information System (GIS) with commonly available 

data was used to develop conservation, restoration, and stormwater management priority indexes 

to clearly identify challenges, opportunities, and 

critical information gaps; formulate a watershedscale strategy; ...The third component - a blend of 

voluntary, place-based strategies for conservation, 

restoration and stormwater management and regulation - was designed to reduce current pollutant 

loading from ... . Finally, a combined emphasis on 

building consensus and political commitment and 

requisite funding for land conservation and pollution mitigation helped ensure that early outcomes 

and successes would foster sustained efforts to 

protect source water.” (pp.123-4).

Susceptibility determination results may 

change if (1) the susceptibility determination value is recalculated using improved, 

updated and/or newly acquired information, 

(2) critical factors not included in the initial 

susceptibility determination are added to 

the susceptibility determination process, and 

change the process itself, or (3) an entirely 

new procedure is used, 

changing the process. 

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The 1997 Guidance presented several possible 

vehicles for disseminating the results of the assessments. However, because of heightened security 

concerns, many states changed their guidelines 

and initial public information plans to restrict access to data that could be seen as sensitive. 

The Environmental Protection Agency’s (EPA’s) Office of Water has developed a policy to manage 

access to sensitive drinking-water-related information that attempts to balance security concerns and 

diverse state handling requirements with public 

health goals, right-to-know requirements, and 

other program and statutory responsibilities. The 

Office of Water recognizes that wide dissemination 

of information is critical for promoting the local 

actions required to protect drinking water resources 

and that increased awareness, as in other security 

efforts, can help increase security.

Appendix C provides contact information for readers who are interested in the Source Water Protection assessment for their PWS.

Most states will provide specific wording as part 

of the assessment report that can be used for this 

purpose. (Asheville, NC is a good example: 

http://www.ci.asheville.nc.us/water/quality.pdf)

Public water suppliers may provide additional 

information in the Consumer Confidence Report. 

This can include the results of efforts to update the 

assessments or progress towards developing and 

implementing a protection plan. Here are two 

good examples of such information:

• Ambient Water Quality Testing for 

Microbial Contaminants in Corvallis, OR. 

(http://www.ci.corvallis.or.us/downloads/pw/

wqreport.pdf) 

• Annual Household Waste Collection Event 

in Milford, MI. (http://www.villageofmilford.

org/1/village/water_quality_report.asp) 

Other good opportunities for publicizing assessment information are through PWS consumer 

information websites such as the Des Moines Water 

Works website for watershed volunteer monitoring: 

http://www.dmww.com/empact_volunteer.asp.

4 . D I S S E M I N AT I N G A S S E S S M E N TS TO T H E 

P U B L I C

At a minimum, when a public water supply 

receives the assessment that was completed 

as part of the state’s EPA-approved 1453 

Source Water Assessment and Protection 

Program2, the public water supply system 

is required to provide information in the 

Consumer Confidence Report about (1) the 

availability of that assessment and (2) a 

summary of the susceptibility of the system 

to contamination. 

2 States use different terms for EPA’s Source Water Assessment and Protection Program, such as the Source Water Assessment Program, the 

Source Water Protection Program and the Protection Program.

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How-To Manual: Update and Enhance Your Local Source Water Protection Assessments

5 . W H AT PA RT N E R S C A N D O A F T E R 

T H E A S S E S S M E N T

Reservoir with sign urging protection of this drinking water source.

After an assessment is completed and its results are disseminated, Partners can tackle the task of creating and 

helping to implement a coordinated action plan for protecting their drinking-water supplies. In most cases, this 

can be done in cooperation with other communities that share the same surface-water or ground-water resource. Partners can also consider development of coordinated emergency responses to contamination incidences.

22
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APPENDIX A: BRIEF DESCRIPTIONS OF METHODS FOR DELINEATING SOURCE WATER 

 PROTECTION AREAS FOR PUBLIC WATER SUPPLY WELLS

METHOD

(from least to 

most technically 

sophisticated)

SUMMARY DESCRIPTION ADVANTAGES LIMITATIONS OTHER

Arbitrary Fixed 

Radius

A circle with an arbitrarily 

specified radial distance 

from the well is drawn 

around the well.

Easy, inexpensive. High degree of uncertainly, likely to overprotect 

the well in one direction 

and under-protect in the 

opposite direction.

Often considered an initial 

delineation approach.

Calculated 

Fixed Radius

A circle is drawn around 

a well at a distance that 

is assumed to specify a 

selected “time of travel”, 

which is the time that it takes 

ground water or a groundwater contaminant to reach 

the well.

Easy, inexpensive, 

limited technical 

expertise required.

More accurate than 

arbitrary fixed radius, 

but has a high degree of 

uncertainly and is likely 

to overprotect the well in 

one direction and underprotect in the opposite 

direction.

Requires well pumping 

rate and an estimate of the 

aquifer porosity.

Simplified 

Variable Shapes

This method assigns 

simple shapes to define 

protection areas, based on 

hydrogeologic and pumping 

conditions at a particular 

well. Method uses analytical 

models and time-of-travel 

considerations to determine 

the shapes of the downgradient and up-gradient 

protection areas, thus 

generally creating source 

water areas that are not 

circular.

Once background 

information is 

collected, requires 

a small amount of 

field data; limited 

technical expertise 

is required. 

May not be accurate in 

areas where geology 

varies locally or where 

ground-water flow 

direction varies.

Uses analytical models and 

time-of-travel considerations; 

rarely used method.

Analytical 

Methods

Source water areas are 

delineated through the 

use of equations to define 

ground-water flow and/or 

contaminant flow-andtransport to the well. 

Methods 

easily used by 

ground-water 

professionals; 

require site-specific 

data.

Costs vary depending 

on amount of field data 

needed.

Widely used method.

Hydrogeologic 

Mapping

Either an existing geologic 

map is used or the area is 

mapped by using geological 

and/or geophysical data 

and/or dye tracing methods. 

Water levels in wells and 

springs are measured; 

dye-tracing may be used to 

identify recharge areas for 

wells in karst areas.

Suitable in many 

settings, but 

particularly useful 

in karst, and 

fractured-bedrock, 

aquifers.

Requires: high level 

of professional 

hydrogeologic 

judgment, expertise 

in geologic mapping 

and/or geologic-map 

interpretation, and 

possibly skill in dye 

tracing; may be costly.

Hydrogeologically based 

SWA boundaries are 

generally practical only when 

geologic maps already exist. 

Numerical 

Flow/Flowand-Transport 

Computer 

Models

Computer models that solve 

mathematical equations to 

determine ground-water 

flow and/or contaminant 

flow and transport.

Most accurate of 

methods when 

performed by a 

ground-water 

professional. 

High level of expertise 

required; higher cost; 

extensive field data 

may be needed; limited 

models available for 

fractured-bedrock, or 

karst, aquifers.

Particularly useful where 

geology is complex and/or 

a relatively high level of 

accuracy is needed.

23
How-To Manual: Update and Enhance Your Local Source Water Protection Assessments

APPENDIX B: USING SANITARY SURVEYS TO UPDATE STATE SOURCE WATER 

 PROTECTION PROGRAMS

 

Note: In the examples below, the states use the 

term “Source Water Assessment program”. 

Sanitary surveys (Surveys) can be adapted to support source water assessments. Three short examples and one extended example are presented 

below. These approaches could be utilized by 

other states wanting to take advantage of the Survey process to enhance or update their Susceptibility Determinations (SDs).

Example 1: State of New York

As part of their agreement with the state, counties in the state of New York will collect additional 

information about their PWSs during Surveys and 

site inspections and enter the data into an add-on 

that the state developed for the SDWIS database. 

The Basic Facility Data form was modified for use 

with the Source Water Assessment Program to contain state-specific information: contaminant history, 

locations of potential contaminant sources and well 

logs. These data were incorporated into assessments as Discrete Contaminant Source Public Water Supply Inventory and as sensitivity drivers and 

other information pertinent to overall susceptibility.

Example 2: State of Louisiana 

Sanitarians in the Louisiana Department of Health 

and Hospitals have conducted sanitary surveys 

that have proven useful for updating Source Water 

Assessment Program data. Health and Hospitals 

has access to the Source Water Assessment Program reports and checks them against the information obtained during sanitary surveys. Health 

and Hospitals notifies the Louisiana Department of 

Environmental Quality if there are any errors in the 

report, such as wells that are incorrectly numbered 

or no longer active. Health and Hospitals also notifies Environmental Quality if new wells have been 

drilled, if a system has been closed, or if a new 

system has come online; new systems are added to 

the source water assessment database.

One Health and Hospitals staff person works with 

Environmental Quality to update the contaminant 

source inventories. This staffer performs the field 

work and then Environmental Quality updates 

the database. Currently, source water areas are 

prioritized for updating based on well-update 

information provided by the Health and Hospitals 

sanitarians, or on a request from such individuals 

and entities as the public, a government agency, or 

a water system. In the future, further prioritization 

would be based on susceptibility to contamination 

(as indicated by Source Water Assessment Program 

data).

Example 3: State of Michigan

The Source Water Assessment Score provides a 

susceptibility determination for Michigan’s noncommunity wells. One element of the Score is noncommunity PWS-well construction, maintenance, 

and use, which are determined as part of the 

sanitary-survey process. States, the PWS, or Source 

Water Protection Partners could take advantage of 

this scoring system to re-evaluate well integrity as 

information becomes available during the sanitarysurvey cycle.

Example 4: State of Nebraska 

The description below consists of selected text from 

Nebraska’s Source Water Assessment Program, 

Chapter V: Source Water Assessment Program 

Vulnerability Analysis (http://www.ndeq.state.ne.us/ 

click on Water Division, scroll down and click on 

SWA Program).

24
www.epa.gov/safewater

A Public Water Supply System’s (PWSS’s) vulnerability to contamination is based on several factors: 

• Integrity of the well (ground water) or intake (surface water) construction.

• Geologic environment, including depth to water, presence of retarding sediments in the subsurface 

(ground water). 

• Nature of the surface water source and watershed-large lake, small stream, large river, etc. 

• Locations of potential contaminant sources in the Wellhead Protection Area or watershed delineation area.

Nebraska is proposing a two phase Vulnerability Assessment, much like the two level Contaminant Source 

Inventory (CSI). The database search that was done as the level one CSI will be provided to Health Department 

field representatives to aid them in completing a Survey for a PWSS. The existing Survey vulnerability determination will be used for the first phase, and a more detailed vulnerability analysis of the PWSS will be done using 

the information from the “on-the-ground” inventory of potential contaminant sources ... and specific site information. This second vulnerability will be called a “Contamination Potential Rating”.

The first phase vulnerability analysis will assist PWSSs in focusing their local voluntary protection activities on the 

wells and locations that are more vulnerable to contamination. As Contamination Potential Ratings are completed, PWSSs will also benefit from this advanced analysis when assessing resources and protection activities for 

the Assessment Area (24 hour Time of Travel) in the watershed or the Wellhead Protection Area. It is also possible that results of the second phase vulnerability will be coordinated in the future to the Drinking Water State 

Revolving Loan Fund ... priority list.

5.1 Vulnerability Definition

For purposes of Nebraska’s Source Water Assessment Program, the terms susceptibility and “vulnerability” are 

interchangeable. Nebraska has chosen to use the word vulnerability. Both the Safe Drinking Water Act Amendments and EPA’s Source Water Assessment and Protection Programs Guidance encourage the use of existing 

information and coordination with other programs. Using the existing Survey for the first phase of the vulnerability analysis is a use of effective information and cooperation between programs. The following chart shows 

examples of the information examined and recorded when a Survey is completed by Nebraska Health and Human Services (Health Department).

Sanitary Survey Inspection Categories Examples 

Records Water - Quality, Quantity, Use, Lab Reports

Wells Site - Access, Drainage, Encroachment

Pumps Base - Seal, Motor Mount, Bolts

Well House Mechanical Piping - Supports, Ties, Sleeves, Corrosion

Auxiliary Equipment Chemical - Safety, Storage, Controls, Pump

Storage Tanks Condition - Structural, Corrosion, Leaks

Truck Fill Location Backflow Prevention - Vacuum Breaker

Distribution System Material Storage and Spare Parts

Operating Practices New Construction and Abandonment

Miscellaneous Wellhead Encroachment Policy, Emergency Plan

Treatment Plant Sites, Structures, Buildings and Bins, Waste Handling

25

This page represents selected text from Nebraska’s Source Water Assessment Program
How-To Manual: Update and Enhance Your Local Source Water Protection Assessments

5.2 Ground Water Systems

5.2.1 Phase One - Existing Sanitary Survey Program

The Health Department visits all PWSSs to conduct a Survey. The phase one vulnerability analysis for the Source 

Water Assessment will not change from the existing Health Department Survey rating. Community PWSSs are visited once every 3 years and Non-Community PWSS are visited once every 5 years. The Survey is a vulnerability 

assessment done within 1000 feet of a well. A well is given a rating of vulnerable or not vulnerable to contamination. Specific components of a PWSS are evaluated in a Survey, including source water, treatment, storage, the 

distribution system, and maintenance.

The phase one vulnerability analysis 1000 feet review distance is not inclusive of the entire source of drinking 

water for the PWSS. However, it has been determined that for a “middle” sized PWSS well, 1000 feet is inclusive 

of the 2 year Time of Travel (TOT) zone within the Wellhead Protection Area. This 1000 foot radius may include 

as much as the 5 year TOT (this 5 year TOT is not routinely calculated for the Wellhead Protection Program). This 

zone is the most crucial area to protect and the Health Department’s regulations reflect this need.

The Nebraska Department of Environmental Quality (Environment Department) intends to use all existing Survey 

data with cooperation from the Health Department to make a “first round” vulnerability analysis. This first phase 

vulnerability analysis will be accessed in the Health Department’s files for the initial Source Water Assessment 

given to the PWS. ... It should be noted that no changes will be made to this already existing Survey program 

and vulnerability assessment. PWSSs may challenge the “vulnerable” or “not vulnerable” rating given to them by 

the Health Department’s ... Being rated “vulnerable” usually means the PWSS may not be eligible for additional 

monitoring waivers.

5.2.2 Phase Two - More Detailed Vulnerability Analysis

A more detailed vulnerability analysis will be made by the Environment Department after the results of the voluntary “on-the-ground” CSI by the PWSS (or individuals, agencies, or organizations helping with inventories) are 

given to the Environment Department. A review of available PWS well information from the Wellhead Protection 

Program file and EPA’s database, SDWIS, of PWS information and violations, will be undertaken and a table 

completed (see Table 5.2). A Vulnerability Score will be the result of filling out the table. The scores will fall into 

different ranges, high to low, that will compare vulnerability of PWSSs across the state (see Table 5.1). It should 

be noted that vulnerability scores will be ranked differently for Community ground water systems, Non-Community ground water systems, and surface water systems. This means a score of 40 does not mean the same thing 

for the above noted categories (see Table 5.7). The second phase vulnerability determination is independent 

of the initial rating by the Health Department’s Survey. This second phase vulnerability determination will help 

PWSSs prioritize and plan local protection activities. 

Table 5.1 Vulnerability Scores Ranking for Ground Water Community PWSSs

It is likely that more information about the well(s) and local geology will be needed after an initial review of the 

Wellhead Protection Program file is completed. The Environment Department will work with the local PWS operator, the Health Department’s field representative and any other organizations which may have more site specific 

information available (Nebraska Rural Water Association, Natural Resources Districts, University Nebraska Lincoln-Conservation and Survey Division, local County Health Departments, etc.). The Environment Department 

may contract with consultants, agencies, or organizations to complete this task. A PWSS may hire a consultant or 

engineer to complete this task, as an addition to a local Wellhead Protection Program. Vulnerability Analyses 

High Vulnerability Medium Vulnerability Low Vulnerability

 > 65 45 - 65 < 45

26

This page represents selected text from Nebraska’s Source Water Assessment Program
www.epa.gov/safewater

done by consultants and engineers on behalf of the PWS will be reviewed by the Environment Department for 

completeness and adequacy prior to acceptance. By the Environment Department performing or reviewing all of 

the Contamination Potential Ratings, statewide consistency will be maintained. 

Table 5.2 - Second Phase Vulnerability Analysis for Ground Water Community PWS wells - ranking by well or by 

well field, only if wells are in close proximity and share similar characteristics. 

Footnotes: 

1. Potential contaminant sources from “on-the-ground” inventory and from the Environment Department’s database search. 

2. Nonpoint sources are usually associated with agricultural production where fertilizers and pesticides are applied. Pasture or wooded 

land is not usually included as potential nonpoint sources of contamination.

27

Characteristic Point System

Depth to water < 10 feet

10 - 50 feet

> 50 feet

Choose one 15

10

0

Vadose (unsaturated) zone (zone above 

water table)

All sand and/or gravel

1 - 15 feet of clay present

> 15 feet of clay present

Choose one 10

5

0

Age of well Constructed before 5/77

Constructed after 5/77, but before 5/86

Constructed (or reconstructed) after 5/86

Choose one 10

0

-10

Potential Contaminant source within 

Wellhead Protection Area1 - includes 

potential nonpoint2 sources

Inside 2 year TOT

Within 2 year to 10 year TOT

Outside 10 year TOT

None

Choose highest value 10

5

2

0

Transportation corridors within Wellhead 

Protection Area

Mainline railroad or pipeline

Major highway or interstate intersection

State or federal highway or interstate

County roads or city/village streets

None

Choose highest value 5

5

2

2

0

Average PWSS nitrate as nitrogen 

concentration over last 5 years

Below or equal to 5 parts/million (ppm)

Between 5 - 7 ppm

Between 7 - 10 ppm

At 10 ppm or above

Choose one -2

0

5

10

Detection of any contaminant regulated 

under drinking water quality standards 

in last 5 years (not including Coliform)

None

Any at or below 50% max contaminant 

level (MCL)

Any above 50% MCL, but < MCL

Any at or above MCL or Administrative Order

Choose one -10

-5

5

20

Existing land use or zoning ordinances 

for water quality concerns or protecting 

PWSS 

None

County

Local Wellhead Protection Program

Choose one 5

0

-10

Natural Resources District Ground Water 

Management Area in place

None

Phase I

Phase II higher

Choose one 5

0

-5

This page represents selected text from Nebraska’s Source Water Assessment Program
How-To Manual: Update and Enhance Your Local Source Water Protection Assessments

5.2.4 Non-Community PWSS

For Non-Community PWSS (both transient and non-transient), the same phased approach to vulnerability assessments will be taken as for Community PWSS, but on a less detailed scale. The first phase will be simply the 

Health Department’s “vulnerable” or “not vulnerable” rating, based on the results of the Survey (done once 

every 5 years for Non-Community PWSSs). 

For the second phase, an area-wide approach will be used. All non-community PWSSs in a county will be plotted on a county, Natural Resources District, or some regional map. Ground water nitrate concentrations for the 

county (or Natural Resources District) from the University of Nebraska - Water Center Clearinghouse project 

(soon to be accessible on the Nebraska Natural Resources Commission internet web site) will be plotted or assessed within a one mile radius of the PWS well(s). Regional nitrate concentrations, PWSS monitoring violations, 

and regional depth to water will be taken into account for this Contamination Potential Rating.

Table 5.3 Second Phase Vulnerability Analysis for Non-Community PWSS 

Characteristic Point System

Monitoring detections of 

regulated contaminant not 

meeting drinking water 

quality standards in last 5 

years (including coliform)

None

Any

0

15

Regional nitrate 

concentrations

Average < 7 ppm in 1 mile radius

Average > 7 ppm in 1 mile radius

0

5

Regional depth to water < 50 feet

> 50 feet

10

0

High Vulnerability Medium Vulnerability Low Vulnerability

20 15 0 - 10

Table 5.4 Vulnerability Scores Ranking for Non-Community PWSS 

As more information about these types of vulnerability assessments become available, the Environment Department will consider refining this process. If deemed necessary, the Environment Department will submit a Source 

Water Assessment Program amendment to EPA.

5.2.5 Vulnerability by Well, Wellfield, or by System

Currently, the Health Department determines vulnerability for individual wells, unless several wells use a common Point of Entry. This same rating by well or Point of Entry will be used for the first phase of vulnerability analysis in the Source Water Assessment Program. 

For the second phase of the vulnerability analysis, the Environment Department will look at wells in the same 

contiguous Wellhead Protection Area for a common vulnerability rating. Often PWSSs will have more than one 

wellfield, separated by more than a mile. Each separate Wellhead Protection Area will be rated using the appropriate table from this section. This second phase rating does not change the rating given by the Health Department in the Survey process; it is intended to be used for planning purposes. 

28

This page represents selected text from Nebraska’s Source Water Assessment Program
www.epa.gov/safewater

5.3 Surface Water Systems

Surface water systems undergo the same Survey with the Health Department as the ground water PWSSs. The 

same two-phased approach will be used for these systems, as explained above. The following table (Table 5.5) 

reflects modifications needed for the surface water systems.

Table 5.5 Second Phase Vulnerability Analysis for Surface Water Systems 

Characteristic Point System

Integrity of intake, from last Health 

Department inspection

Poor 

Adequate 

Excellent

Choose one 10

2

0

Size of Watershed Delineation Area > 35 square miles

< 35 square miles

Choose one 10

0

Potential contaminant source 

within Assessment Area2 – includes 

potential nonpoint3 sources and 

permitted discharges

Present 

Absent

Choose one 15

0

Transportation corridors within 

Assessment Area (24 hour TOT)

Main line railroad or 

pipeline

Major highway or interstate 

intersection

State or federal highway or 

interstate 

County roads or city/village 

streets

None

Choose highest value

5

5

2

2

0

Detection of any contaminant 

regulated under drinking water 

quality standards in last 5 years (not 

including coliform)

None

Any at or below 50% MCL 

Any above 50% MCL, but 

less than MCL 

Any at or above MCL or 

Administrative Order

Choose highest value -10

-5

5

20

Existing land use or zoning 

ordinances for water quality 

concerns 

None 

County 

Local Watershed Protection 

Program or project4

Choose highest value 5

0

-10

Footnotes: 

2. Potential contaminant sources from “on-the-ground” inventory 

3. Nonpoint sources are usually associated with agricultural production where fertilizers and pesticides are applied. Pasture or wooded 

land are not usually included as potential nonpoint sources of contamination. 

4. Local Watershed Protection program or project could be a CWA 319 project, Nebraska Environmental 

Trust project, or other local/state program to protect the watershed and/or educate the public.

29

This page represents selected text from Nebraska’s Source Water Assessment Program
How-To Manual: Update and Enhance Your Local Source Water Protection Assessments

Table 5.6 Vulnerability Scores Ranking for Surface Water Community PWSS 

5.3.1 Explanation of Table Characteristics

Many of the Vulnerability Analysis characteristics are the same between ground water and surface water systems. 

Please see section 5.2.3 for these common explanations. 

Table 5.7 Summary of Different Types of PWSSs Vulnerability Scores 

Integrity of Intake, from Last Health Department Inspection

The health Department routinely inspects surface water intakes as part of their Survey program and ongoing 

work with PWSSs. Integrity of an intake structure for a surface water system should include: 

• Withdrawal of water from more than one level if quality varies with depth (most often in a lake, but if the 

potential exists for a chemical spill it may also apply to a river). 

• Should be a valve at each inlet and also a valve in the pipeline in case inlet valves are damaged/malfunctioning. 

• Adequate protection against damage by ice, anchors, etc.

Integrity and safety of the intake to accident are evaluated in this inspection and reflect on the vulnerability of the 

system to contamination.

Size of Watershed Delineation Area 

A PWSS in a larger watershed delineation area will be more vulnerable to contamination than a smaller one due 

to a greater number of potential sources.

Existing Land Use or Zoning Ordinances for Water Quality Concerns

Counties may have controls (zoning, ordinances, etc.) that are protective of water quality. Local sponsors (such 

as Natural Resources Districts, City of Omaha, etc.) have implemented watershed or lake projects that put Best 

Management Practices on the land and help educate land owners about surface water quality. Points are given 

for these types of projects that could lower a PWSS’s vulnerability.

5.4 Responsibility

The Environment Department will assume the responsibility of compiling the data from the Survey Program with 

assistance from the Health Department, for the first phase of the vulnerability assessment/analysis. After the 

results of the voluntary “on-the-ground” inventory are given to the Environment Department, it will also undertake the Contamination Potential Ratings for a PWSS. In addition, the state or its contractors/cooperators will do 

a Contamination Potential Rating (including a second round CSI within 3 hour TOT) for all surface water systems 

in Nebraska by May 2003. The goal for the Contamination Potential Ratings is to complete 90% of the PWSSs by 

the year 2010. A new Source Water Assessment, reflecting the Contamination Potential Rating, will be sent to the 

PWSS. An explanation of how the new vulnerability score was determined will be provided. The PWSS owner will 

be required to make this Assessment known and available to the public. 

 Type of PWSS High Vulnerability Medium Vulnerability Low Vulnerability

 Community, Ground Water > 65 45 - 65 < 45

 Non-Community, Ground Water > 20 15 0 - 10

 Surface Water > 40 20 - 40 < 20

 High Vulnerability Medium Vulnerability Low Vulnerability

 > 40 20 - 40 < 20

30

This page represents selected text from Nebraska’s Source Water Assessment Program
www.epa.gov/safewater

Alabama: contact the water supplier.

Alaska: contact the water supplier or Alaska 

Resources Library and Information Services 

(907-272-7547). 

Arizona: contact Donna Lucchese (602-771-

4641), Arizona Department of Environmental 

Quality, Source Water Assessment and Protection 

Unit.

Arkansas: http://www.healthyarkansas.com/eng/

swp/swapinfo.htm (see pull-down menu; scroll 

down to and click on, eng-public water system 

information; navigate to water system of interest; 

clearly state that you would like a source water protection assessment report); alternately contact Lyle 

Godfrey (501-661-2623), Arkansas Department of 

Health.

California: http://swap.ice.ucdavis.edu/TSinfo/

TSsearch.asp 

Colorado: http://www.cdphe.state.co.us/wq/sw/

SWAP/swapreports.html 

Connecticut: http://www.dph.state.ct.us/BRS/

water/source_protection/Assessments/Assessments.

htm

Delaware: http://www.wr.udel.edu/swaphome/

swassessments.html

District of Columbia: http://www.potomacriver.

org/water_quality/swapreport.htm 

Florida: http://www.dep.state.fl.us/swapp/

SelectCounty.asp

Georgia: available for review at the Georgia 

Environmental Protection Division office in Atlanta 

(contact: Sue Grunwald, 404-656-0719), or at the 

water supplier. 

Hawaii: contact the water supplier.

Idaho: http://www.deq.state.id.us/water/

SWAReports/InternetQuery.cfm

Illinois: http://www.epa.state.il.us/water/

groundwater/source-water-assessment/ 

Indiana: contact the water supplier for communitysystem assessments; for non-community assessments contact James Sullivan (317-308-3388), 

Indiana Department of Environmental Management.

Iowa: contact Michael Anderson (515-725-0336), 

Iowa Department of Natural Resources; assessments are available on a case-by-case basis.

Kansas: http://www.kdheks.gov/nps/swap/

SWreports.html 

Kentucky: contact Bill Caldwell (502-564-3410), 

Natural Resources and Environmental Protection 

Cabinet, Watershed Management Branch.

Louisiana: contact the water supplier.

Maine: contact Robin Frost (207-287-2070), 

Division of Environmental Health, Drinking Water 

Program.

Maryland: contact the central library of the county, 

the County Environmental Health Director, the water supplier, the County Public Works or the Public 

Planning and Zoning departments.

Massachusetts: http://www.mass.gov/dep/water/

drinking/swap.htm

Michigan: contact Elgar Brown P.E. (517-241-

1359), Department of Environmental Quality.

Minnesota: http://156.98.150.16/swa/

pdwmain.cfm

Mississippi: http://deq.state.ms.us/MDEQ.nsf/

page/GPB_SourceWaterAssessment

Missouri: http://drinkingwater.missouri.edu (Note: 

An ID must be obtained to use this website. IDs 

are available from the water system or from the 

Missouri Department of Natural Resources, Public 

Drinking Water Branch [573-751-5331]).

APPENDIX C: WHERE TO FIND SOURCE WATER ASSESSMENTS

(Note: in many states where the water supplier is listed as the contact, the supplier has the option of providing 

access to the assessments on a case-by-case basis.)

31
How-To Manual: Update and Enhance Your Local Source Water Protection Assessments

Montana: http://nris.state.mt.us/wis/swap/

swapquery.asp

Nebraska: contact Deana Barker (402-471-6988), 

Nebraska Department of Environmental Quality, 

Water Quality Division.

Nevada: contact Jim Balderson (775-687-9517), 

Nevada Division of Environmental Protection. 

New Hampshire: http://www.des.state.nh.us/

dwspp/reports.htm 

New Jersey: http://www.state.nj.us/dep/swap/

assessments.htm

New Mexico: contact Darren Padilla (505-476-

8631), New Mexico Environment Department.

New York: contact the County Health Department 

or the water supplier.

North Carolina: http://www.deh.enr.state.nc.us/

pws/swap, click on Learn About Your Drinking Water Source (Computer Application).

North Dakota: contact Jim Horner (701- 328-

5216), North Dakota Department of Health. 

Ohio: contact the Ohio Environmental Protection 

Agency, Division of Drinking and Ground Waters 

(614-644-2752) or the water supplier.

Oklahoma: contact the Oklahoma Department of 

Environmental Quality, Environmental Compliance 

and Local Services Division (405-702-6100) for 

further information.

Oregon: http://www.deq.state.or.us/wq/dwp/

dwphome.htm 

Pennsylvania: http://164.156.71.80/WXOD.aspx, 

has summaries only; for a full assessment report 

contact the water supplier or the regional office 

of the Pennsylvania Department of Environmental 

Protection.

Puerto Rico: http://prdata.er.usgs.gov/swap/, click 

on Search PWS database. 

Rhode Island: http://www.health.ri.gov/

environment/dwq/swap/index.php 

South Carolina: http://www.scdhec.net/water/

html/srcewtr.html#reports 

South Dakota: contact the water supplier; with the 

supplier’s concurrence the state will provide the 

assessment.

Tennessee: summaries can be found at: 

http://gwidc.memphis.edu/website/dws/risk/ ; see 

also http://www.state.tn.us/environment/dws/

dwassess.shtml; for further information, contact 

Thomas A. Moss, (615-532-0170), Tennessee 

Department of Environment and Conservation, 

Division of Water Supply. 

Texas: contact the water supplier. 

Utah: contact the water supplier.

Vermont: assessments may be viewed at the water 

system; they may also be viewed or obtained from 

the Vermont Department of Environmental Conservation, Water Supply Division (802-241-3400).

Virginia: contact Virginia Department of Health, 

Office of Water (804-864-7500) for field-office 

phone numbers.

Washington: contact David Jennings (360-236-

3149), Washington State Department of Health, 

Information Management Section.

West Virginia: contact Scott Rodeheaver (304-558-

6713), West Virginia Department of Health.

Wisconsin: contact the water supplier.

Wyoming: contact Kim Parker (307-777-6128), 

Wyoming Department of Environmental Quality. 

32
www.epa.gov/safewater

Source Water Protection Partners may find reading the following assessments particularly helpful when 

considering updates and enhancements (this is not an exhaustive list): 

Philadelphia

Oregon

Assessments posted on the Montana website

New Jersey

APPENDIX E: ACRONYMS

•

•

•

•

CSI: Contaminant Source Inventory

EPA: Environmental Protection Agency (United States EPA, unless stated otherwise)

MCL: Maximum Contaminant Limit

PCS: Potential Contaminant Source

ppm: parts per million

PWS: Public Water Supply (depending on context, may also mean public water supply system)

PWSS: Public Water Supply System

SD: Susceptibility Determination

SWA: Source Water Area (in some states, this area may be called the Source Water Protection Area, 

the 1453 Area, or the Protection Area)

SWP: Source Water Protection

TOT: Time of Travel

USDA: U.S. Department of Agriculture

APPENDIX D: HELPFUL EXAMPLES OF ASSESSMENTS

33
34

EPA816-K-06-004

Office of Water

September 2006