Illicit Discharge
   Detection and Elimination
            A Guidance Manual for
   Program Development and Technical Assessments
by the
Center for
Watershed Protection
Robert Pitt
University of Alabama
October 2004


The information in this document has been funded wholly or in part by the United States
Environmental Protection Agency under cooperative agreement X-82907801-0. Although it has been
subjected to the Agency's peer and administrative review, it does not necessarily reflect the views
of the Agency, and no official endorsement should be inferred. Also, the mention of trade names  or
commercial products does not imply endorsement by the United States government, the Center for
Watershed Protection, or the University of Alabama.

A                               for

                          Edward Brown and Deb Caraco
                          Center for Watershed Protection
                           Ellicott City, Maryland 21043


                                   Robert Pitt
                              University of Alabama
                           Tuscaloosa, Alabama 35487
                           EPA Cooperative Agreement
                                 Project Officer
                                Bryan Rittenhouse
                              Water Permits Division
                          Office of Water and Wastewater
                       U.S. Environmental Protection Agency
                                Washington, D.C.

Photo Acknowledgments
Figure Number                Source
2	Snohomish County, WA
4	Fort Worth Department of Environmental Management (DEM)
5	Fort Worth DEM
8	Dr. Robert Pitt, University of Alabama
16	Fort Worth DEM
18	HorsleyWhitten
28 (fire hydrant)	Fort Worth DEM
34 (highly turbid discharge)	Rachel Calabro, Massachusetts Department of Environmental Protection
34 (industrial discharge)	Dr. Robert Pitt
34 (paint)	Dr. Robert Pitt
34 (Toronto industrial spill)	Dr. Robert Pitt
34 (blood)	Fort Worth DEM
34 (failing septic)	Snohomish County, WA
34 (construction site)	Don Green, Franklin, TN
34 (discharge of rinse water)	Rachel Calabro
35 (natural foam)	Snohomish County, WA
35 (high severity suds)	Fort Worth DEM
35 (moderate severity oil)	R. Frymire
35 (high severity oil)	Kelly Dinsmore, City of Newark, DE
38 (bright red bacteria)	R. Frymire
38 (Sporalitis filamentous)	Robert Ressl, City of Arlington, TX
38 (extreme algal growth)	Mark Sommerfield, Montgomery Co., Maryland
38 (brownish algae)	R. Frymire
39 (all but 'brownish stain')	R. Frymire
41 (all)	R. Frymire
42	Galveston, TX
48	Fort Worth DEM
49	Dr. Robert Pitt
52-53	Jewell, 2001
58-59	Jewell, 2001
60	Sargent and Castonguay, 1998
63	NEIWPCC, 2003,
71 (a)	Snohomish County, WA
71 (b)	King County, WA
72	Mecklenburg, NC Water Quality Program
73	U.S. EPA, 1999


A number of past projects have found that
dry-weather flows discharging from storm
drainage systems can contribute significant
pollutant loadings to receiving waters.
If these loadings are ignored (by only
considering wet-weather stormwater runoff,
for example), little improvement in receiving
water conditions may occur. Illicit dry-
weather flows originate from many sources.
The most important sources typically
include sanitary wastewater or industrial and
commercial pollutant entries, failing septic
tank systems, and vehicle maintenance

Provisions of the Clean Water Act (1987)
require National  Pollutant Discharge
Elimination  System (NPDES) permits
for storm water discharges. Section 402
(p)(3)(B)(ii) requires that permits for
municipal separate storm sewers shall
include a requirement to effectively prohibit
problematic non-storm water discharges into
storm sewers. Emphasis is placed on the
elimination of inappropriate connections to
urban storm drains. This requires affected
agencies to identify and locate sources of
non-storm water discharges into storm
drains so they may institute appropriate
actions for their elimination.

This Manual is intended to provide support
and guidance, primarily to Phase II NPDES
MS4 communities, for the establishment of
Illicit Discharge Detection and Elimination
(IDDE) programs and the design and
procedures of local investigations of non-
storm water entries into storm drainage
systems. It also has application for Phase
I communities looking to modify existing
programs and community groups such as
watershed organizations that are interested
in providing reconnaissance and public
awareness services to communities as part
of watershed restoration activities.

This Manual was submitted in partial
fulfillment of cooperative agreement X-
82907801-0 under the sponsorship of the
U.S. Environmental Protection Agency. This
report covers a period from July 2001 to
July 2004  and  was prepared by the Center
for Watershed  Protection, Ellicott City,
MD in cooperation with Robert Pitt of the
University of Alabama.

Some references in the document pertain
to work conducted during this project. This
internal support information was developed
as work tasks were completed and research
findings were developed. In some cases,
memoranda or technical support documents
were prepared. Most of these documents are
in "draft"  form and have not been published.
As a result, they should be  considered
supplemental and preliminary information
that is not intended for widespread citation
or distribution. In  the References section,
these documents are identified as "IDDE
project support material" at the end of each
citation. Interested readers  can access these
documents through the website link to the
project archive and support information.
Illicit Discharge Detection and Elimination: A Guidance Manual

                            Illicit Discharge Detection and Elimination: A Guidance Manual


This Guidance Manual could not have
been completed had it not been for the
contributions of many individuals. Much
of the field survey and laboratory analysis
guidance in this manual reflects an update to
information presented in Pitt et. al. (1993).
Bob Pitt and his students and researchers
have been instrumental in furthering
the  science to develop and identify safe,
quick, accurate and cost effective methods
to collect and analyze dry weather flow
samples. Team members from the University
of Alabama that contributed to this manual
include: Bob Pitt, Soumya Chaturvedula,
Sanju Jacob, Veera Karri, Uday
Khambhammettu, Alex Maestre, Renee
Morquecho, Yukio Nara, and Sumandeep
Shergill. Team members from the Center
for Watershed Protection include Jessica
Brooks, Ted Brown, Karen Cappiella, Deb
Caraco, Tom Schueler, Stephanie Sprinkle,
Paul Sturm, Chris Swann, Tiffany Wright,
and Jennifer Zielinski.

Support from EPA has been constant and
valuable.  We would like to thank Wendy
Bell and Jack Faulk of the Office of
Wastewater, and in particular, project officer,
Bryan Rittenhouse.

We are grateful to the many communities
that agreed to fill out our extensive surveys
and questionnaires including:
•   Erica Anderson Maguire, Ada County
    Highway District, ID
*   Charles Caruso, City of Albuquerque,
•  Bill Hicks, City of Alexandria, VA
*  Jason Papacosma, Arlington County, VA
•  Roger Click and Roxanne Jackson, City
   of Austin, TX
•  Bill Stack, Baltimore City, MD
*  Amy Schofield, Boston Water and Sewer
   Commission, MA
*  John Nardone and James Wilcox, City of
   Cambridge, MA
*  Andrew Swanson, Clackamas County, OR
ซ  Michele Jones, City of Dayton, OH
•  John H. Cox, City of Durham, NC
•  Moe Wadda, City of Falls Church, VA
ป  Angela Morales, Howard County, MD
•  David Hagerman and Bob Jones, City of
   Knoxville, TN
ซ  Alan  Searcy, City of Lakewood, CO
*  Meosotis Curtis and David Rotolone,
   Montgomery County, MD
*  Michael Loffa, City of Phoenix, AZ
•  Ali Dirks, City of Portland, OR
*  Mark Senior, City of Raleigh, NC
•  Beth Schmoyer, City of Seattle, WA
•  Todd Wagner, City of Springfield, MO
*  Arne Erik Anselm, City of Thousand
   Oaks, CA
*  Dean Tuomari, Wayne County, MI
•  David Harris, City of Worcester, MA

Others that provided useful insight into
their community programs include Michael
Hunt, City of Nashville, TN; Mecklenburg
Illicit Discharge Detection and Elimination: A Guidance Manual

County, NC; and Steve Jadlocki, City of
Charlotte, NC.

The communities of Baltimore City, MD;
Baltimore County, MD; Boston Water and
Sewer Commission, MA; Cambridge, MA,
Dayton, OH; Fort Worth, TX; Raleigh, NC;
Tuscaloosa, AL; and Wayne County, MI
were extremely generous in hosting project
team members and sharing the details of
their programs. A special thanks goes to
Baltimore City, MD and Baltimore County,
MD for providing access to laboratory and
field equipment, and allowing protocols to be
tested in their sub water sheds. Baltimore City
staff members we would like to recognize
include: Bill Stack, Dr. Freddie Alonzo, Ted
Eucare, Shelly Jesatko, Hector Manzano,
Umoja  Muleyyar, Van Sturtevant, and Joan
White.  Baltimore County staff we would
like to recognize include Steve Stewart and
Steve Adamski.

Many of the outstanding graphics in the
Manual were provided by outside sources.
While sources are noted on the back of the
                 title page, we would like to especially thank
                 the following:
                 •  Rachel Calabro, MA DEP
                 ซ  Kelly Dinsmore, City of Newark, DE
                 *  Donette Dunaway, California RWQCB
                    Region 3
                 *  Fort Worth Department of
                    Environmental Management
                 *  Roger Frymire
                 •  Dave Graves, New York DOT
                 *  Don Green, Franklin, TN
                 *  Hillsborough County Public Works
                    Department, Stormwater Management
                 *  Rusty Rozzelle, Mecklenburg County,
                 *  Mark Sommerfield, Montgomery
                    County, MD
                 *  Greg Stockton, Stockton Infrared
                    Thermographic Services, Inc.
                 *  Barry Tonning, Tetra Tech
Illicit Discharge Detection and Elimination: A Guidance Manual

                                                                          Table of Contents
Table of Contents
Foreword	i
Acknowledgments	Mi
List of Tables	viii
List of Figures	ix

Introduction	1

Chapter 1: The Basics of Illicit Discharges	   5
1.1     Important Terminology and Key Concepts	  5
1.2     The Importance of Illicit Discharges in Urban Water Quality	15
1.3     Regulatory Background For Illicit Discharges	16
1.4     Experience Gained in Phase 1	19

Chapter 2: Components of an Effective IDDE Program	23
2.1     Management Tips to Develop an Effective IDDE Program	25

Chapter 3: Auditing Existing Resources and Programs	29
3.1     Audit Overview	30
3.2     Develop Infrastructure Profile	32
3.3     Establish Legal Authority	32
3.4     Review Available Mapping	33
3.5     Availability of Field Staff	33
3.6     Access to Laboratory Analysis	34
3.7     Education and Outreach	34
3.8     Discharge Removal Capability and Tracking	35
3.9     Program Funding	35
3.10    The Initial IDDE Program Plan	38

Chapter 4: Establishing Responsibility  and Legal Authority	39
4.1     Identify Responsible Department/Agency	40
4.2     Develop Local Illicit Discharge Ordinance	40

Chapter 5: Desktop Assessment of Illicit Discharge Potential	45
5.1     Overview of Desktop Assessment of Illicit Discharge Potential	46

Chapter 6: Developing Program Goals and Implementation Strategies	57
6.1     Overview of Goals and Strategies Development	58
6.2     Develop Initial Program Goals	58
6.3     Crafting Implementation Strategies	60

Chapter 7: Searching for Illicit Discharge Problems in the Field	63
7.1     Overview of Searching for Illicit Discharge Problems in the Field	64
7.2     The Outfall Reconnaissance Inventory (ORI)	64
7.3     Interpreting ORI Data	65
Illicit Discharge Detection and Elimination: A Guidance Manual

Table of Contents

7.4     Design and Implementation of an Indicator Monitoring Strategy	66
7.5     Field and Lab Safety Considerations	68

Chapter 8: Isolating and Fixing Individual Illicit Discharges	69
8.1     Overview of Isolating and Fixing Individual Illicit Discharges	70
8.2     Isolating Illicit Discharges	70
8.3     Fixing Illicit Discharges	73

Chapter 9: Preventing Illicit Discharges	75
9.1     Overview of Preventing Illicit Discharges	76
9.2     Methods to Identify Opportunities for Illicit Discharge Prevention	76
9.3     Preventing Illicit Discharges from Neighborhoods	76
9.4     Preventing Illicit Discharges from Generating Sites	80
9.5     Preventing Illicit Discharges from Municipal Operations	83
9.6     Budgeting and Scoping Pollution Prevention	86

Chapter 10: IDDE Program Tracking and Evaluation	87
10.1    Overview of Program Evaluation	88
10.2    Evaluate the Program	88

Chapter 11: The Outfall Reconnaissance Inventory (ORI)	91
11.1     Getting Started	91
11.2    Desktop Analysis to Support the ORI	94
11.3    Completing the ORI	96
11.4    ORI Section  1-Background Data	98
11.5    ORI Section 2-Outfall Description	99
11.6    ORI Section 3-Quantitative Characterization for Flowing Outfalls	101
11.7    ORI Section 4-Physical Indicators for Flowing Outfalls Only	103
11.8    ORI Sheet Section 5-Physical Indicators for Both Flowing and Non-Flowing Outfalls	107
11.9    ORI Section 6-8 Initial Outfall Designation and Actions	109
11.10   Customizing the ORI for Your Community	110
11.11    Interpreting ORI Data	112
11.12   Budgeting and Scoping the ORI	116

Chapter 12: Indicator Monitoring	119
12.1    Indicator Parameters to Identify Illicit Discharges	121
12.2    Sample Collection Considerations	122
12.3    Methods to Analyze Indicator Samples	124
12.4    Techniques to Interpret Indicator Data	130
12.5    The Chemical Library	136
12.6    Special Monitoring Techniques for Intermittent or Transitory Discharges	138
12.7    Monitoring of Stream Quality During Dry Weather	141
12.8    The Costs of Indicator Monitoring	144

Chapter 13: Tracking Discharges to A Source	147
13.1    Storm Drain Network Investigations	147
13.2    Drainage Area Investigations	158
vi                              Illicit Discharge Detection and Elimination: A Guidance Manual

                                                                            Table of Contents

13.3    On-site Investigations	159
13.4    Septic System Investigations	166
13.5    The Cost to Trace Discharge Sources	170

Chapter 14: Techniques to Fix Discharges	173
14.1    Implementation Considerations	173

References	R-l

Appendix A: Generating Sites, Storm Water Regulatory Status, and Discharge Potential	A-l

Appendix B: Model Illicit Discharge and Connection Ordinance	B-l

Appendix C: Six Steps to Establishing a Hotline and Reporting and Tracking System	C-l

Appendix D: Outfall Reconnaissance Inventory Field Sheet	D-l

Appendix E: Flow Type Data from Tuscaloosa and Birmingham	E-l

Appendix F: Laboratory Analytical Procedures for Outfall Monitoring	F-l

Appendix G: Sampling Protocol Considerations	G-l

Appendix H: Two Alternative Flowcharts	H-l

Appendix I: User's Guide for the Chemical Mass Balance Model (CMBM) Version 1.0	1-1

Appendix J: Using the Chemical Library to Determine the Utility of Boron as an Indicator
             of Illicit Discharges	J-l

Appendix K: Specific Considerations for Industrial Sources of Inappropriate Pollutant
             Entries to the Storm Drainage System	K-l
Illicit Discharge Detection and Elimination: A Guidance Manual                             vii

Table of Contents

List  of Tables

1. Comparative "Fingerprint" of Flow Types	8
2. Land Uses, Generating Sites and Activities That Produce Indirect Discharges	12
3. Linking Other Municipal Programs to IDDE Program Needs	21
4. Key Tasks and Products in IDDE Program Implementation	24
5. Comparison of IDDE Components	25
6. Potential Local Agencies and Departments to Contact During an Audit	30
7. Potential IDDE Audit Questions	31
8. Codes and Ordinances with Potential Links to IDDE	33
9. Summary of Annual Phase I IDDE Program Costs	36
10. Average Correction Costs	36
11. IDDE Program Costs	37
12. Summary of IDDE-Related Enforcement Tools	44
13. Useful Data for the Desktop Assessment	48
14. Defining Discharge Screening Factors in a Community	50
15. Prioritizing Subwatershed Using IDP Screening Factors	53
16. Community-wide Rating of Illicit Discharge Potential	54
17. Measurable Goals for an IDDE Program	60
18. Linking Implementation Strategies to Community-wide IDP	61
19. Customizing Strategies for Unique Subwatershed Screening Factors	62
20. Field Screening for an IDDE Program	65
21. Field Data Analysis for an IDDE Program	66
22. Indicator Monitoring Considerations	66
23. Benefits and Challenges of a Complaint Hotline	70
24. Steps to Creating and Maintaining Successful IDDE Hotline	71
25. IDDE Complaint Hotline Costs	71
26. Methods to Fix Illicit Discharges	74
27. Common Discharges Produced at Generating Sites	81
28. Summary of Local Household Hazardous Waste Collection Programs	85
29. Estimated Costs for Public Awareness Program Components	86
30. Resources Needed to Conduct the ORI	92
31. Climate/Weather Conditions for Starting the ORI	92
32. Outfalls to Include in the Screening	96
33. Special Considerations for Open Channels/Submerged Outfalls	Ill
34. Outfall Designation System Using ORI Data	115
35. An Example of ORI Data Being Used to Compare Across Subwatersheds	115
36. Using Stream and ORI Data to Categorize IDDE Problems	115
37. Typical Field Equipment Costs for the ORI	116
38. Example ORI Costs	117
39. Indicator Parameters Used to Detect Illicit Discharges	122
40. Equipment Needed for Sample Collection	123
41. Basic Lab Supplies	126
42. Analytical Methods Supplies Needed	127
43. Chemical Analysis Costs	128
44. Typical  Per Sample Contract Lab Costs	130
45. Benchmark Concentrations to Identify Industrial Discharges	134
46. Usefulness of Various Parameters to Identify Industrial Discharges	135
47. Where and How to Sample for Chemical "Fingerprint"  Library	137
viii                             Illicit Discharge Detection and Elimination: A Guidance Manual

                                                                           Table of Contents
48. Evaluation of the Flow Chart Method Using Data from Birmingham, Alabama	139
49. Follow-Up Monitoring for Transitory Discharges	142
50. Typical "Full Body Contact Recreation" Standards for E. coll	143
51. Example In-Stream Nutrient Indicators of Discharges	143
52. Indicator Monitoring Costs: Two Scenarios	145
53. Methods to Attack the Storm Drain Network	148
54. Basic Field Equipment Checklist	152
55. Field Procedure for Removal of Manhole Covers	153
56. Techniques to Locate the Discharge	160
57. Key Field Equipment for Dye Testing	161
58. Dye Testing Options	162
59. Tips for Successful Dye Testing	163
60. Septic System Homeowner Survey Questions	167
61. Common Field Equipment Needed for Dye, Video, and Smoke Testing	170
62. Equipment Costs for Dye Testing	171
63. Equipment Costs for Video Testing	171
64. Equipment Costs for Smoke Testing	171
65. Methods to Eliminate Discharges	175
List of  Figures
1. Sewer Pipe Discharging to the Storm Drain System	7
2. Direct Discharge from a Straight Pipe	8
3. A Common Industrial Cross Connection	9
4. Accident Spills Are Significant Sources of Illicit Discharges	  9
5. Dumping at a Storm Drain Inlet	10
6. Routine Outdoor Washing and Rinsing Can Cause Illicit Discharges	10
7. Non-Target Landscaping Irrigation Water	10
8. GIS Layers of Outfalls in a Subwatershed	49
9. Communities With Minimal (a), Clustered (b), and Severe (c) Illicit Discharge Problems	55
10. Measuring an Outfall as Part of the ORI	64
11. Some Discharges Are Immediately Obvious	64
12. IDDE Monitoring Framework	67
13. Process for Removing or Correcting an Illicit Discharge	74
14. Storm Drain Stenciling May Help Reduce  Illicit Discharges	77
15. Home Mechanic Changing His Automotive Fluids	78
16. Household Hazardous Wastes Should be Properly Contained to Avoid Indirect Discharges	79
17. Swimming Pools Can Be a Source of Illicit  Discharges	80
18. Spill Response Often Involves Portable Booms and Pumps	82
19. Walk All Streams and Constructed Open Channels	91
20. Example of a Comprehensive Emergency Contact List for Montgomery County, MD	94
21. Survey Reach Delineation	95
22. Typical Outfall Types Found in the Field	97
23. Section 1 of the ORI Field Sheet	98
24. A Variety of Outfall Naming Conventions Can Be Used	99
25. Corrugated Plastic Pipe	99
26. Section 2 of the ORI Field Sheet	100
27. Measuring Outfall Diameter	100
Illicit Discharge Detection and Elimination: A Guidance Manual                              ix

Table of Contents
28. Characterizing Submersion and Flow	101
29. Section 3 of the ORI Field Sheet	102
30. Measuring Flow (as volume per time)	102
31. Measuring Flow (as velocity times cross-sectional area)	103
32. Section 4 of the ORI Field Sheet	103
33. Using a Sample Bottle to Estimate Color and Turbidity	104
34. Interpreting Color and Turbidity	105
35. Determining the Severity of Floatables	106
36. Synthetic Versus Natural Sheen	107
37. Section 5 of the ORI Field Sheet	107
38. Interpreting Benthic and Other Biotic Indicators	108
39. Typical Findings at Both Flowing and Non-Flowing Outfalls	109
40. Sections 6-8 of the ORI Field Sheet	110
41. Cold Climate Indicators  of Illicit Discharges	112
42. One Biological Indicator is this Red-Eared Slider Turtle	112
43. Sample Screen from ORI Microsoft Access Database	114
44. IDDE Monitoring Framework	119
45. Analyzing Samples in the Back of a Truck	126
46. Office/Lab Set-up	126
47. Flow Chart to Identify Illicit Discharges in Residential Watersheds	131
48. OBM Trap That Can Be Placed at an Outfall	140
49. Stream Sentinel Station	141
50. Example Investigation Following the Source Up the Storm Drain System	148
51. Key Initial Sampling Points Along the Trunk of the Storm Drain	150
52. Storm Drain Schematic Identifying "Juncture Manholes"	151
53. A Process For Following Discharges Down the Pipe	151
54. Traffic Cones Divert Traffic From Manhole Inspection Area	152
55. Manhole Observation and Source Identification	153
56. Techniques to Sample from the Storm Drain	154
57. Use of Ammonia as a Trace Parameter To Identify an Illicit Discharge	155
58. Boston Water and Sewer Commission Manhole Inspection Log	156
59. Example Sandbag Placement	157
60. Optical Brightener Placement in the Storm Drain	158
61. Symptom and Diagnosis	159
62. Laundromat Discharge	159
63. Dye Testing Plumbing	160
64. Dye Testing in a  Manhole	161
65. Camera Being Towed	164
66. Tractor-Mounted Camera	164
67. Review of an Inspection  Video	164
68. Smoke Testing System Schematic	165
69. Smoke Candles	165
70. Smoke Blower	166
71. Surface Indicators	168
72. Aerial Thermography Showing Sewage Leak	169
73. Dead Vegetation and Surface Effluent are Evidence of a Septic System Surface Failure	169
                               Illicit Discharge Detection and Elimination: A Guidance Manual


An up-to-date and comprehensive manual
on techniques to detect and correct
discharges in municipal storm drains has
been unavailable until now. This has been
a major obstacle for both Phase I and Phase
II National Pollutant Discharge Elimination
System (NPDES) municipal separate storm
sewer system (MS4) communities that
must have programs in place that detect,
eliminate, and prevent illicit discharges to
the storm drain system. Smaller Phase II
communities, in particular, need simple
but effective program guidance to comply
with permits issued by the Environmental
Protection Agency (EPA) and states.
This manual provides communities with
guidance on establishing and implementing
an effective Illicit Discharge Detection  and
Elimination (IDDE) program.

Studies have shown that dry weather
flows from the storm drain system may
contribute a larger annual discharge mass
for some pollutants than wet weather storm
water flows (EPA, 1983 and Duke, 1997).
Detecting and eliminating these illicit
discharges involves complex detective work,
which makes it hard to establish a rigid
prescription to "hunt down" and correct all
illicit connections. Frequently, there is no
single approach to take, but rather a variety
of ways to get from detection to elimination.
Local knowledge and available resources can
play significant roles in determining which
path to take. At the very least,  communities
need to systematically understand and
characterize their stream, conveyance, and
storm sewer infrastructure  systems. When
illicit discharges are identified, they need
to be removed. The process is ongoing
and the effectiveness of a program should
improve with time. In fact, well-coordinated
IDDE programs can benefit from and
contribute to other community-wide water
resources-based programs, such as public
education, storm water management, stream
restoration, and pollution prevention.

This manual incorporates the experience
of more than 20 Phase I communities that
were surveyed about their practices, levels
of program effort, and lessons learned
(CWP, 2002). These communities took
many different approaches to solve the
IDDE problem, and provided great insights
on common obstacles, setting realistic
expectations and getting a hard job done
right. Many of the IDDE methods presented
in this manual were first developed and
tested in many Phase I communities.
Specific techniques applied in a community
should be adapted to local conditions, such
as dominant discharge types, land use, and
generating sites.

Designed with a broad audience in mind,
including agency heads, program managers,
field technicians and water quality
analysts, this manual is primarily focused
on providing the thousands of Phase II
communities that are now in the process of
developing IDDE programs with guidance
for the development and implementation of
their own programs. The manual has been
organized to address the broad range of
administrative and technical considerations
involved with setting up an effective IDDE
program. The first 10 chapters of the Manual
focus on "big picture" considerations needed
to successfully get an IDDE program off
Illicit Discharge Detection and Elimination: A Guidance Manual

the ground. The final four chapters provide
detailed technical information on the
methods to screen, characterize and remove
illicit discharges in MS4 communities.
These chapters present the state-of-the-
practice on specific monitoring techniques
and protocols.

In general, the content of this manual gets
progressively more complex and technical
toward the end. The basic organization
of the manual is outlined below. The
information is provided to help:

•  Define important terminology and
   understand key illicit discharge concepts

ป  Conduct an audit  to understand
   community needs and capabilities

•  Establish adequate legal authority

•  Develop a tracking system to map
   outfalls and document reported illicit

•  Conduct desktop analyses to prioritize
   targets for illicit discharge control

•  Conduct rapid reconnaissance of the
   stream corridor to find problem outfalls

•  Apply new analytical and field methods
   to find and fix illicit discharges

ป  Educate municipal employees and the
   public to prevent discharges

ป  Estimate costs to  run a program and
   conduct specific investigations

Chapter 1. The Basics of Illicit Discharges -
The many different sources and generating
sites that can produce illicit discharges are
described  in Chapter 1. The chapter also
outlines key concepts and terminology
needed to  understand illicit discharges, why
they cause water quality problems and the
regulatory context for managing them.
                  Chapter 2. Components of an Effective
                  Illicit Discharge Program-This chapter
                  presents an overall framework to build
                  an IDDE program, by outlining eight key
                  components of good programs. Each of the
                  following eight chapters is dedicated to a key
                  program component. The first page of the
                  program component chapters is notated with
                  a puzzle icon labeled with the applicable
                  program component number.

                  Chapter 3. Audit Existing Resources
                  Programs™ This chapter provides guidance
                  on evaluating existing resources, regulations,
                  and ongoing activities in your community to
                  better address illicit discharges.

                  Chapter 4. Establish Responsibility,
                  Authority and Tracking- This chapter
                  presents guidance on how to identify the
                  local  agency who will be responsible for
                  administering the IDDE program, and
                  how to establish the legal authority to
                  control illicit discharges by adapting an
                  existing ordinance or adopting a new one.
                  The chapter also describes how to set
                  up a program tracking system needed to
                  document discharges and local actions to
                  respond to them.

                  Chapter 5. Desktop Assessment of
                  Illicit Discharge Potential™ The fifth
                  chapter describes desktop analyses
                  to process available mapping data to
                  quickly characterize and screen illicit
                  discharge problems at the community and
                  subwatershed scale. Key factors include
                  water quality, land use, development age,
                  sewer infrastructure and outfall density.
                  Rapid screening techniques are presented
                  to define where to begin searching for illicit
                  discharge problems in your community.

                  Chapter 6. Developing Program
                  Goals     Implementation Strategies-
Illicit Discharge Detection and Elimination: A Guidance Manual

Communities are required to establish
and track measurable goals for their IDDE
program under the NPDES MS4 permit
program. This chapter recommends a series
of potential program goals that can guide
local efforts, as well as guidance on how
to measure and track progress toward their

Chapter 7. Searching for Illicit Discharge
Problems in the Field- This chapter
briefly summarizes the major monitoring
techniques to find illicit discharges, and
discusses how to select the right combination
of monitoring methods to incorporate into
your local program.

Chapter 8. Isolating     Fixing
Individual Illicit  Discharges-The methods
used to find and remove illicit discharges are
briefly described in this chapter and include
citizen hotlines and techniques to trace,
locate and remove illicit discharge sources.

Chapter 9. Preventing Illicit Discharges -
Prevention is a cost effective way to reduce
pollution from illicit discharge. This chapter
highlights a series of carrot and stick
strategies to prevent illicit discharges.

Chapter 10. IDDE Program Evaluation-
IDDE programs must continually evolve
to changing local conditions. This chapter
describes how to review and revisit program
goals to determine if they are being met and
to make any needed adjustments.

Chapter 11. The Outfall Reconnaissance
Inventory (ORI)- The chapter presents
detailed protocols  to conduct rapid field
screening  of problem outfalls. The chapter
also outlines the staff and equipment costs
needed to  conduct an ORI, and presents
methods to organize, manage and interpret
the data you collect.
Chapter 12. Chemical Monitoring- This
chapter presents detailed guidance on
the wide range of chemical monitoring
options that can be used to identify the
composition of illicit discharge flows. The
chapter begins by describing different
chemical indicators that have been used
to identify illicit discharges, and presents
guidance on how to collect samples for
analysis. The chapter recommends a  flow
chart approach that utilizes four  chemical
indicators to distinguish the flow type. The
chapter provides specific information on
other analytical methods that can be used, as
well  as proper safety, handling, and disposal
procedures. Simple and more sophisticated
methods for interpreting monitoring data
are discussed, along with comparative cost

Chapter 13. Tracking Discharges to Their
Source- This chapter  describes  how to
investigate storm drain systems to  narrow
and remove individual illicit discharges.
These techniques include "trunk"
investigations (e.g., video surveillance,
damming, and infiltration and inflow
studies) and on-site investigations (e.g., dye
tests, smoke tests, and pollution prevention
surveys). The pros and cons of each
investigation technique are discussed, and
comparative cost estimates are given.

Chapter 14. Techniques to Fix
Discharges- This chapter provides tips
on the best methods to repair or eliminate
discharges. Specific  advice is presented on
how  to identify responsible parties, develop
pre-approved subcontractor lists, and
estimate unit costs for typical repairs.

Appendices-Eleven technical appendices
are provided at the end of the manual.
Illicit Discharge Detection and Elimination: A Guidance Manual

                                                        Chapter 1: The Basics of Illicit Discharges
             Chapter 1: The Basics of Illicit Discharges
      An understanding of the nature of illicit
      discharges in urban watersheds is essential
      to find, fix and prevent them. This chapter
      begins by defining the terms used to
      describe illicit discharges, and then reviews
      the water quality problems they cause. Next,
      the chapter presents the regulatory context
      for controlling illicit discharges, and reviews
      the experience local communities have
      gained in detecting and eliminating them.

      1.1    Important Terminology
      and Key Concepts

      This Manual uses several important terms
      throughout the text that merit upfront
      explanation. This section defines the
      terminology to help program managers
      perform important illicit discharge detective
      work in their communities. Key concepts
      are presented to classify illicit discharges,
      generating sites and control techniques.

      Illicit Discharge

      The term "illicit discharge" has many
      meanings in regulation1 and practice, but we
      use a four-part definition in this manual.

      1. Illicit discharges are defined as a storm
         drain that has measurable flow during
         dry weather containing pollutants
         and/or pathogens. A storm drain
         with measurable flow but containing
         no pollutants is simply considered a
2.  Each illicit discharge has a unique
   frequency, composition and mode of
   entry in the storm drain system.

3.  Illicit discharges are frequently caused
   when the sewage disposal system
   interacts with the storm drain system. A
   variety of monitoring techniques is used
   to locate and eliminate illegal sewage
   connections. These techniques trace
   sewage flows from the stream or outfall,
   and go back up the pipes or conveyances
   to reach the problem connection.

4.  Illicit discharges of other pollutants are
   produced from specific source areas
   and operations known as "generating
   sites." Knowledge about these generating
   sites can be helpful to locate and
   prevent non-sewage illicit discharges.
   Depending on  the regulatory status of
   specific "generating sites," education,
   enforcement and other pollution
   prevention techniques can be used to
   manage this class of illicit discharges.

Communities need to define illicit
discharges as part  of an illicit discharge
ordinance. Some non-storm water discharges
to the MS4 may be allowable, such as
discharges resulting from fire fighting
activities and air conditioning condensate.
Chapter 4 provides more  detail on ordinance
      140 CFR 122.26(b)(2) defines an illicit discharge as any
      discharge to an MS4 that is not composed entirely of storm
      water, except allowable discharges pursuant to an NPDES
      permit, including those resulting from fire fighting activities.
      Illicit Discharge Detection and Elimination: A Guidance Manual

Preceding Page Blank

Chapter 1: The Basics of Illicit Discharges
A storm drain can be either an enclosed
pipe or an open channel. From a regulatory
standpoint, major storm drains are defined
as enclosed storm drain pipes with a diameter
of 36 inches, or greater or open channels that
drain more than 50 acres. For industrial land
uses, major drains are defined as enclosed
storm drain pipes 12 inches or greater in
diameter and open channels that drain more
than two acres. Minor storm drains are
smaller than these thresholds. Both major and
minor storm drains can be a source of illicit
discharges, and both merit investigation.

Some "pipes"  found in  urban areas may
look like storm drains but actually serve
other purposes. Examples include foundation
drains, weep holes, culverts, etc. These pipes
are generally not considered storm drains
from a regulatory or practical standpoint.
Small diameter "straight pipes," however,
are a common source of illicit discharges
in many communities and should be
investigated to determine if they are a
pollutant source.

Not all dry weather storm drain flow
contains pollutants or pathogens.  Indeed,
many communities find that storm drains
with dry weather flow are, in fact, relatively
clean. Flow in these drains may be derived
from springs, groundwater seepage, or leaks
from water distribution pipes. Consequently,
field testing and/or water quality sampling
are needed to confirm whether pollutants are
actually present in dry weather flow, in order
to classify them as an illicit discharge.

The  frequency of dry weather discharges
in storm drains is important, and can be
classified as continuous, intermittent or
Continuous discharges occur most or all
of the time, are usually easier to detect,
and typically produce the greatest pollutant
load. Intermittent discharges occur over
a shorter period of time (e.g., a few hours
per day or a few days per year). Because
they are infrequent, intermittent discharges
are hard to detect, but can still represent a
serious water quality problem, depending on
their flow type. Transitory discharges occur
rarely, usually  in response to a  singular
event such as an industrial spill, ruptured
tank,  sewer break, transport accident or
illegal dumping episode. These discharges
are extremely hard to detect with routine
monitoring, but under the right conditions,
can exert severe water quality problems on
downstream receiving waters.

Dry weather discharges are composed of one
or more possible flow types:

•  Sewage and septage flows are produced
   from sewer pipes and septic systems.

ซ  Washwater flows are generated from a
   wide variety of activities  and operations.
   Examples include discharges of gray
   water (laundry) from homes,  commercial
   carwash wastewater, fleet washing,
   commercial laundry wastewater, and
   floor washing to shop drains.

•  Liquid wastes refers to a wide variety
   of flows, such as oil, paint, and process
   water (radiator flushing water, plating
   bath wastewater, etc.) that enter the
   storm drain system.

•  Tap water flows are derived from
   leaks and losses that occur during
   the distribution of drinking water in
   the water supply system. Tap water
   discharges in the storm drain system
   may be more prevalent in communities
                              Illicit Discharge Detection and Elimination: A Guidance Manual

                                                   Chapter 1: The Basics of Illicit Discharges
   with high loss rates (i.e., greater than
   15%) in their potable water distribution
   system, (source of 15% is from National
   Drinking Water Clearinghouse http://

•  Landscape irrigation flows occur when
   excess potable water used for residential
   or commercial irrigation ends up in the
   storm drain system.

•  Groundwater and spring water flows
   occur when the local water table rises
   above the bottom elevation of the storm
   drain (known as the invert) and enters
   the storm drain either through cracks
   and joints, or where open channels or
   pipes associated with the MS4 may
   intercept seeps and springs.

Water quality testing is used to conclusively
identify flow  types found in storm drains.
Testing can distinguish illicit flow types
(sewage/septage, washwater and liquid
wastes) from cleaner discharges (tap water,
landscape irrigation and ground water).

Each flow type has a distinct chemical
fingerprint. Table 1 compares the pollutant
fingerprint for different flow types in
Alabama. The chemical fingerprint  for each
flow type can differ regionally, so it is a
good idea to develop  your own "fingerprint"
library by sampling each local flow type.

In practice, many storm drain discharges
represent a blend of several flow types,
particularly at larger outfalls that drain
larger catchments. For example, groundwater
flows often dilute sewage thereby masking
its presence. Chapter 12 presents  several
techniques to help isolate illicit discharges
that are blended with cleaner discharges.
Illicit discharges are also masked by high
volumes of storm water runoff making it
difficult and frequently impossible to detect
them during wet weather periods.

Mode of Entry

Illicit discharges can be further classified
based on how they enter the storm drain
system. The mode of entry can either be
direct or indirect. Direct entry means that
the discharge is directly connected to the
storm drain pipe through a sewage pipe,
shop drain, or other kind of pipe. Direct
entry usually produces discharges that are
continuous or intermittent. Direct entry
usually occurs when two different kinds of
"plumbing" are improperly connected. The
three main situations where this occurs are:

Sewage cross-connections: A sewer pipe that
is improperly connected to the storm drain
system produces a continuous discharge of
raw sewage to the pipe (Figure 1). Sewage
cross-connections can occur in catchments
where combined sewers or septic systems
are converted to a separate sewer system,
and a few pipes get "crossed."

Straight pipe: This term refers to relatively
small diameter pipes that intentionally
bypass the sanitary connection or septic
drain fields, producing a direct discharge
into open channels or streams as shown in
Figure 2.
    Figure 1: Sewer Pipe Discharging to
          the Storm Drain System
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 1: The Basics of Illicit Discharges
Table 1: Comparative "Fingerprint" (Mean Values) of Flow Types
Flow Type
Laundry Washwater
Car Washwater
Plating Bath (Liquid
Industrial Waste**)
Radiator Flushing
(Liquid Industrial
Tap Water
Landscape Irrigation
(mg/L as
50 (0.26)*
45 (0.33)
71 (0.27)
52 (0.27)
25 (0.53)*
87 (0.4)
3.2 (0.89)
66 (0.66)
26 (0.89)
<0.06 (0.55)
6.5 (0.78)
3.6 (0.67)
2801 (0.13)
3.1 (0.55)
5.6 (0.5)
502 (0.42)
463.5 (0.88)
274 (0.45)
3280 (0.21)
140 (0.07)
0.7 (0.1)*
0.93 (0.39)
0.85 (0.4)
5.1 (0.47)
0.94 (0.07)
0.61 (0.35)
758 (0.27)
6.8 (0.68)
* The number in parentheses after each concentration is the Coefficient of Variation; NA = Not Applicable
** All values are from Tuscaloosa, AL monitoring except liquid wastes and septage, which are from Birmingham, AL.
Sources: Pitt (project support material) and Pitt et al. (1993)
H8v..  v*v35
                                                 Sewage has the greatest potential to
                                                produce direct illicit discharges within
                                                any urban subwatershed, regardless of
                                                the diverse land uses that it comprises.
                                                The most commonly reported sewage-
                                                 related direct discharges are broken
                                                  sanitary sewer lines (81% of survey
                                                 respondents), cross-connections (71%
                                                 of survey respondents), and straight
                                                    pipe discharges (38% of survey
                                                     respondents). (CWP, 2002).
        Figure 2: Direct Discharge
           from a Straight Pipe
Industrial and commercial cross-
connections: These occur when a drain
pipe is improperly connected to the storm
drain  system producing a discharge of wash
water, process water or other inappropriate
flows  into the storm drain pipe. A floor
shop drain that is illicitly connected to the
storm drain system is illustrated in Figure 3.
                                  Older industrial areas tend to have a higher
                                  potential for illicit cross-connections.

                                  Indirect entry means that flows generated
                                  outside the storm drain system enter through
                                  storm drain inlets or by infiltrating through
                                  the joints of the pipe. Generally, indirect
                                  modes of entry produce intermittent or
                                  transitory discharges, with the exception of
                                  groundwater seepage. The five main modes
                                  of indirect entry for discharges include:

                                  Groundwater seepage into the storm drain
                                 pipe: Seepage frequently occurs in storm
                             Illicit Discharge Detection and Elimination: A Guidance Manual

                                                    Chapter 1: The Basics of Illicit Discharges
drains after long periods of above average
rainfall. Seepage discharges can be either
continuous or intermittent, depending on
the depth of the water table and the season.
Groundwater seepage usually consists of
relatively clean water that is not an illicit
discharge by itself, but can mask other illicit
discharges. If storm drains are located close
to sanitary sewers, groundwater seepage
may intermingle with diluted sewage.

Spills that enter the storm drain system at
an inlet: These transitory discharges occur
when a spill travels across an impervious
surface and enters a storm drain inlet. Spills
can occur at many industrial, commercial
and transport-related sites. A very common
example is an oil or gas spill from an
accident that then travels across the road and
into the storm drain system (Figure 4).

Dumping a liquid into a storm drain inlet:
This type of transitory discharge is created
when liquid wastes such as oil, grease, paint,
solvents, and various automotive  fluids are
dumped into the storm drain (Figure 5).
Liquid dumping occurs intermittently at
sites that improperly dispose of rinse water
and wash water during maintenance and
cleanup operations. A common example is
cleaning deep fryers in the parking lot of
fast food operations.

Outdoor washing activities that create flow
to a storm drain inlet: Outdoor washing may
or may not be an illicit discharge, depending
on the nature of the generating site that
produces the wash water. For example,
hosing off individual sidewalks and
driveways may not generate significant flows
or pollutant loads. On the other hand, routine
washing of fueling areas, outdoor storage
areas, and parking lots (power washing), and
construction equipment cleanouts may result
in unacceptable pollutant loads (Figure 6).

Non-target irrigation from landscaping
or lawns that reaches the storm drain
system: Irrigation can produce intermittent
discharges from over-watering or
misdirected  sprinklers that send tap water
over impervious areas (Figure 7). In some
instances, non-target irrigation can produce
unacceptable loads of nutrients, organic
matter or pesticides. The most common
example is a discharge from commercial
landscaping  areas adjacent to parking lots
connected to the storm drain system.
    Figure 3: A common industrial cross
  connection is a floor drain that is illicitly
        connected to a storm drain
   Figure 4: Accident spills are significant
  sources of illicit discharges to the storm
               drain system
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 1: The Basics of Illicit Discharges
  Figure 5: Dumping at a storm drain inlet
                    Figure 6: Routine outdoor washing and
                      rinsing can cause illicit discharges
                             Figure 7: Non-target landscaping
                                     irrigation water
Land Use and Potential Generating
Land use can predict the potential for
indirect discharges, which are often
intermittent or transitory. Many indirect
discharges can be identified and prevented
using the concept of "generating sites,"
which are sites where common operations
can generate indirect discharges in a
community. Both research and program
experience indicate that a small subset of
generating sites within a broader land use
category can produce most of the indirect
                  discharges. Consequently, the density
                  of potential generating sites within a
                  subwatershed may be a good indicator of the
                  severity of local illicit discharge problems.
                  Some common generating sites within major
                  land use categories are listed in Table 2, and
                  described below.

                  Residential Generating Sites: Failing
                  septic systems were the most common
                  residential discharge reported in 33% of
                  IDDE programs surveyed (CWP, 2002). In
                  addition, indirect residential discharges were
Illicit Discharge Detection and Elimination: A Guidance Manual

                                                  Chapter 1: The Basics of Illicit Discharges
also frequently detected in 20% of the IDDE
programs surveyed, which consisted of oil
dumping, irrigation overflows, swimming
pool discharges, and car washing. Many
indirect discharges are caused by common
residential behaviors and may not be
classified as "illicit" even though they can
contribute to water quality problems. With
the exception of failing septic systems and
oil dumping, most communities have chosen
education rather than enforcement as the
primary tool to prevent illicit discharges
from residential areas.

Commercial Generating Sites: Illicit
discharges from commercial sites were
reported as frequent in almost 20% of local
IDDE programs surveyed (CWP, 2002).
Typical commercial discharge generators
included operations such as outdoor
washing; disposal of food wastes; car
fueling, repair, and washing; parking
lot power washing; and poor dumpster
management. Recreational areas, such
as marinas and campgrounds, were also
reported to be a notable source of sewage
discharges. It is important to note that
not all businesses within a generating
category actually produce illicit discharges;
generally only a relatively small fraction
do. Consequently, on-site inspections of
individual businesses are needed to confirm
whether a property is actually a generating
     Sewage can also be linked to significant indirect illicit discharges in the form of
     sanitary sewer overflows (52% of survey respondents), sewage infiltration/inflow
  (48% of survey respondents), and sewage dumping from recreational vehicles (33% of
                           survey respondents) (CWP, 2002).
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 1: The Basics of Illicit Discharges
      Table 2: Land Uses, Generating Sites and Activities That Produce Indirect Discharges
 Land Use
Generating Site
Activity that Produces Discharge
• Apartments
• Multi-family
                 Single Family Detached
  Car Washing
  Driveway Cleaning
  Dumping/Spills (e.g., leaf litter and RV/boat
  holding tank effluent)
  Equipment Washdowns
  Lawn/Landscape Watering
  Septic System Maintenance
  Swimming Pool Discharges
  Campgrounds/RV parks
  Car Dealers/Rental Car Companies
  Car Washes
  Commercial Laundry/Dry Cleaning
  Gas Stations/Auto Repair Shops
  Nurseries and Garden Centers
  Oil Change Shops
  Swimming Pools
  Building Maintenance (power washing)
  Landscaping/Grounds Care (irrigation)
  Outdoor Fluid Storage
  Parking Lot Maintenance (power washing)
  Vehicle Fueling
  Vehicle Maintenance/Repair
  Vehicle Washing
  Washdown of greasy equipment and grease
  Auto recyclers
  Beverages and brewing
  Construction vehicle washouts
  Distribution centers
  Food processing
  Garbage truck washouts
  Marinas, boat building and repair
  Metal plating operations
  Paper and wood products
  Petroleum storage and refining
• All commercial activities
• Industrial process water or rinse water
• Loading and un-loading area washdowns
• Outdoor material storage (fluids)
  Corporate Campuses
  Schools and Universities
• Building Maintenance (e.g., power washing)
• Dumping/Spills
• Landscaping/Grounds Care (irrigation)
• Parking Lot Maintenance (power washing)
                                                      Vehicle Washing
  Maintenance Depots
  Municipal Fleet Storage Areas
  Public Works Yards
  Streets and Highways
  Building Maintenance (power washing)
  Landscaping/Grounds Care (irrigation)
  Outdoor Fluid Storage
  Parking Lot Maintenance (power washing)
  Road Maintenance
  Spill Prevention/Response
  Vehicle Fueling
  Vehicle Maintenance/Repair
  Vehicle Washing
                  Illicit Discharge Detection and Elimination: A Guidance Manual

                                                    Chapter 1: The Basics of Illicit Discharges
Industrial Generating Sites: Industrial sites
produce a wide range of flows that can
cause illicit discharges. The most common
continuous discharges are operations
involving the disposal of rinse water, process
water, wash water and contaminated, non-
contact cooling water. Spills and leaks,
ruptured pipes, and leaking underground
storage tanks are also a source of indirect
discharges. Illicit discharges from industry
were detected in nearly 25% of the local
IDDE programs surveyed (CWP, 2002).

Industries are classified according to
hundreds of different Standard Industrial
Classification (SIC) codes. The SIC
coding system also includes commercial,
institutional and municipal  operations2.
Many industries are required to have storm
water pollution prevention and spill response
plans under EPA's Industrial Storm Water
NPDES Permit Program. A complete list of
the industries covered by the Storm Water
NPDES Permit Program can be found in
Appendix A.  The appendix also rates each
industrial category based on its potential to
produce illicit discharges, based on analysis
by Pitt (2001).

Institutional Generating Sites: Institutions
such as hospitals, corporate campuses,
colleges, churches, and cemeteries can be
generating sites if routine maintenance
practices/operations create discharges from
parking lots and other areas. Many large
institutional sites have their own areas for
fleet maintenance, fueling, outdoor storage,
and loading/unloading that can produce
indirect discharges.
2More recently, federal agencies including EPA, have adopted
the North American Industry Classification System (NAICS,
pronounced "Makes") as the industry classification system.
For more information on the NAICS and how it correlates
with SIC, visit
Municipal Generating Sites: Municipal
generating sites include operations that
handle solid waste, water, wastewater, street
and storm drain maintenance, fleet washing,
and yard waste disposal. Transport-related
areas such as streets and highways, airports,
rail yards, and ports can also generate
indirect discharges from spills, accidents and

Finding, Fixing, and Preventing
Illicit Discharges

The purpose of an IDDE program is to find,
fix and prevent illicit discharges, and a series
of techniques exist to meet these objectives.
The remainder of the manual describes
the major tools used to build a local IDDE
program, but they are briefly introduced

Finding Illicit Discharges
The highest priority in most programs is to
find any continuous and intermittent sewage
discharges to the storm drain system. A
range of monitoring techniques can be
used to find sewage discharges. In general,
monitoring techniques are used to find
problem areas and then trace the problem
back up the  stream or pipe to identify the
ultimate generating site or connection.
Monitoring can sometimes pick up other
types of illicit discharge that occur on
a continuous or intermittent basis (e.g.,
wash water and liquid wastes). Monitoring
techniques are classified into three major

•   Outfall Reconnaissance Inventory

•   Indicator Monitoring at Storm Water
    Outfalls and In-stream

•   Tracking Discharges to their Source
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 1: The Basics of Illicit Discharges
                                    !!!  Caution !!!
     Using land use as an indicator for certain flow types such as sewage is often less
   reliable than other factors in predicting the potential severity of sewage discharges.
    More useful assessment factors for illicit sewage discharges include the age of the
     sewer system, which helps define the physical integrity and capacity of the pipe
  network, as well as age of development, which reveals the plumbing codes and practices
   that existed when individual connections were made over time. Two particular critical
      phases in the sewer history of a subwatershed are when sanitary sewers were
  extended to replace existing septic systems, or when a combined sewer was separated.
     The large number of new connections and/or disconnections during these phases
                       increases the probability of bad plumbing.
Fixing Illicit Discharges

Once sewage discharges or other
connections are discovered, they can be
fixed, repaired or eliminated through several
different mechanisms. Communities should
establish targeted education programs along
with legal authority to promote timely
corrections. A combination of carrots and
sticks should be available to deal with the
diversity of potential dischargers.
                 Preventing Illicit Discharges

                 The old adage "an ounce of prevention is
                 worth a pound of cure" certainly applies
                 to illicit discharges. Transitory discharges
                 from generating sites can be minimized
                 through pollution prevention practices
                 and well-executed spill management and
                 response plans. These plans should be
                 frequently practiced by local emergency
                 response agencies and/or trained workers at
                 generating sites. Other pollution prevention
                 practices are described in Chapter 9 and
                 explored in greater detail in Manual 8 of the
                 Urban Subwatershed Restoration Manual
                 Series (Schueler et al, 2004).
                          National Urban Runoff Project
    EPA's National Urban Runoff Project (NURP) studies highlighted the significance of
  pollutants from illicit entries into urban storm sewerage (EPA, 1983). Such entries may
  be evidenced by flow from storm sewer outfalls following substantial dry periods. Such
  flow, frequently referred to as "baseflow" or "dry weather flow", could be the result of
  direct "illicit connections" as mentioned in the NURP final report (EPA, 1983), or could
   result from indirect connections (such as leaky sanitary sewer contributions through
    infiltration). Many of these dry weather flows are continuous and  would therefore
    occur during rain induced runoff  periods. Pollutant contributions from dry weather
  flows in some storm drains have been shown to be high enough to significantly degrade
   water quality because of their substantial contributions to the annual mass pollutant
                    loadings to receiving waters (project research).
Illicit Discharge Detection and Elimination: A Guidance Manual

                                                   Chapter 1: The Basics of Illicit Discharges
1.2    The                 of

Dry and wet weather flows have been
monitored during several urban runoff
studies. These studies have found that
discharges observed at outfalls during dry
weather were significantly different from
wet weather discharges. Data collected
during the 1984 Toronto Area Watershed
Management Strategy Study monitored and
characterized both storm water flows and
baseflows (Pitt and McLean, 1986). This
project involved intensive monitoring in two
test areas (a mixed residential/commercial
area and an industrial area) during warm,
cold, wet, and dry weather. The annual mass
discharges of many pollutants were found to
be greater in dry weather flows than in wet
weather flows.

A California urban discharge study identified
commercial and residential discharges
of oil and other automobile-related fluids
as a common problem based on visual
observations (Montoya, 1987). In another
study, visual inspection of storm water pipes
discharging to the Rideau River in Ontario
found leakage from sanitary sewer joints or
broken pipes to be a major source of storm
drain contamination (Pitt, 1983).

Several urban communities conducted
studies to identify and correct illicit
connections to their storm drain systems
during the mid-1980s. These studies were
usually taken in response to receiving water
quality problems or as part of individual
NURP research projects. The  studies
indicated the magnitude and extent of
cross-connection problems in many urban
watersheds. For example, Washtenaw
County, Michigan tested businesses to locate
direct illicit connections to the county storm
drain system. Of the 160 businesses tested,
38% were found to have illicit storm drain
connections (Schmidt and Spencer, 1986).
An investigation of the separate storm sewer
system in Toronto, Ontario revealed 59% of
outfalls had dry weather flows, while 14%
of the total outfalls were characterized as
"grossly polluted," based on a battery of
chemical tests (GLA, 1983). An inspection
of the 90 urban storm water outfalls draining
into Grays Harbor in Washington showed
that 32% had dry weather flows (Pelletier
and Determati, 1988). An additional 19
outfalls were considered suspect, based on
visual observation and/or elevated pollutant
levels compared to typical urban storm
water runoff.

The Huron River Pollution Abatement
Program ranks as one of the most thorough
and systematic early investigations of illicit
discharges (Washtenaw County, 1988). More
than a thousand businesses, homes and other
buildings located in the watershed  were dye
tested. Illicit connections were found at 60%
of the automobile-related businesses tested,
which included service stations, automobile
dealerships, car washes, and auto body and
repair shops. All plating shops inspected were
found to have illicit storm drain connections.
Additionally, 67% of the manufacturers, 20%
of the private service agencies and 88% of the
wholesale/retail establishments tested were
found to have illicit storm sewer connections.
Of the 319 homes dye tested, 19 were found
to have direct sanitary connections to storm
drains. The direct discharge of rug-cleaning
wastes into storm drains by carpet cleaners
was also noted as a common problem.

Eliminating illicit discharges is a critical
component to restoring urban watersheds.
When bodies of water cannot meet
designated uses for drinking water, fishing,
or recreation, tourism and waterfront home
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 1: The Basics of Illicit Discharges
values may fall; fishing and shellfish
harvesting can be restricted or halted; and
illicit discharges can close beaches,
primarily as a result of bacteria
contamination. In addition to the public
health and economic impacts associated with
illicit discharges, significant impacts to
aquatic life and wildlife are realized.
Numerous fish kills and other aquatic life
losses have occurred in watersheds as a
result of illicit or accidental dumping and
spills that have resulted in lethal pollutant
concentrations in receiving waters.


The history of illicit discharge regulations
is long and convoluted, reflecting an
ongoing debate as to whether they  should be
classified as a point or nonpoint source of
pollution. The Clean Water Act amendments
of 1987 contained the first provisions to
specifically regulate discharges from storm
drainage systems. Section 402(p)(3)(B)
provides that "permits for such discharges:

(i)  May be issued on a system or
    jurisdiction-wide basis

(ii) Shall include a requirement to
    effectively prohibit non-storm water
    discharges into the storm sewers; and

(iii) Shall require controls to reduce the
    discharge of pollutants to the maximum
    extent practical including management
    practices, control techniques and system
    design and engineering methods, and
    such provisions as the Administrator or
    the State determines  appropriate for the
    control of such pollutants."

In the last 15 years, NPDES permits  have
gradually been applied to a greater range of
communities. In 1990, EPA issued a  final
                    rule, known as Phase I to implement section
                    402 (p) of the Clean Water Act through the
                    NPDES permit system. The EPA effort
                    expanded in December 1999,  when the
                    Phase II final rule was issued. A summary
                    of how both rules pertain to MS4s and illicit
                    discharge control is provided  below.

                               Of                /

                    The NPDES Phase I permit program
                    regulates municipal separate storm sewer
                    systems (MS4s) meeting the following

                    •   Storm sewer systems located in an
                       incorporated area with a population of
                       100,000 or more

                    ซ   Storm sewer systems located in 47
                       counties identified by EPA as having
                       populations over 100,000  that were
                       unincorporated but considered urbanized

                    •   Other storm sewer systems that are
                       specially designated based on the
                       location of storm water discharges with
                       respect to waters of the United States,
                       the size of the discharge, the quantity
                       and nature of the pollutants discharged,
                       and the interrelationship to other
                       regulated storm sewer systems, among
                       other factors

                    An MS4 is defined as any conveyance or
                    system of conveyances that is owned or
                    operated by a state or local government
                    entity designed for collecting and conveying
                    storm water, which is not part of a Publicly
                    Owned Treatment Works. The total number
                    of permitted MS4s in the Phase I program is
Illicit Discharge Detection and Elimination: A Guidance Manual

                                                     Chapter 1: The Basics of Illicit Discharges
                                PHASE I HIGHLIGHTS

  Who  must meet the requirements?
  How many Phase I communities
  exist nationally?

  What  are the requirements  related
  to illicit discharges?
MS4s with population

Develop programs to prevent, detect and
remove illicit discharges
Phase I MS4s were required to submit a
two-part application. The first part required
information regarding existing programs and
the capacity of the municipality to control
pollutants. Part 1 also required identification
of known "major" outfalls3 discharging
to waters of the United States, and a field
screening analysis of representative major
outfalls to detect illicit connections. Part
2 of the application required identification
of additional major outfalls, limited
monitoring, and a proposed storm water
management plan (EPA,  1996).

Phase I communities were required to
develop programs to detect and remove
illicit discharges, and to control and prevent
improper disposal into the MS4 of materials
such as used oil  or seepage from municipal
sanitary  sewers. The illicit discharge
programs were required to include the
following elements:

•   Implementation and enforcement of an
    ordinance, orders or similar means to
    prevent illicit discharges to the MS4
3A "major" outfall is defined as an MS4 outfall that dis-
charges from a single pipe with an inside diameter of at
least 36 inches, or discharges from a single conveyance
other than a circular pipe serving a drainage area of more
than 50 acres. An MS4 outfall with a contributing industrial
land use that discharges from a single pipe with an inside
diameter of 12 inches or more or discharges from a single
conveyance other than a circular  pipe serving a drainage
area of more than two acres.
      •  Procedures to conduct ongoing field
         screening activities during the life of the

      •  Procedures to be followed to investigate
         portions of the separate storm sewer
         system that, based on the results of the
         field screening required in Part 2 of
         the application, indicate a reasonable
         potential for containing illicit discharges
         or other sources of non-storm water

      •  Procedures to prevent, contain, and
         respond to spills that may discharge into
         the MS4

      •  A program to promote, publicize, and
         facilitate public reporting of the presence
         of illicit discharges or water quality
         impacts associated with discharges from
         the MS4

      •  Educational activities, public information
         activities, and other appropriate activities
         to facilitate the proper management and
         disposal of used oil and toxic materials

      •  Controls to limit infiltration of seepage
         from municipal sanitary sewers to the
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 1: The Basics of Illicit Discharges


The Phase II Final Rule, published in the
Federal Register regulates ,MS4s that meet
both of the following criteria:

•  Storm sewer systems that are not a
   medium or large MS4 covered by
   Phase I of the NPDES Program

ซ  Storm sewer systems that are located in
   an Urbanized Area (UA) as defined by
   the Bureau of the Census, or storm sewer
   systems located outside of a UA that
   are designated by NPDES permitting
   authorities because of one of the
   following reasons:

   - The MS4's discharges cause, or have
       the potential to cause, an adverse
       impact on water quality

   — The MS4 contributes substantially to
       the pollutant loadings of a physically
       interconnected MS4 regulated by the
       NPDES  storm water program

MS4s that meet the above criteria are
referred to as regulated small MS4s. Each
regulated small  MS4 must satisfy six
minimum control measures:

1.  Public education and outreach

2.  Public participation/involvement

3.  Illicit discharge detection and

4.  Construction site runoff control

5.  Post-construction runoff control

6.  Pollution prevention/Good housekeeping

Under the third  minimum measure, an illicit
discharge is defined as any discharge to an
MS4 that is not composed entirely of storm
water, except allowable discharges pursuant
to an NPDES permit, including those
resulting from  fire fighting activities (40
CFR 122.26(b)(2)). To satisfy this minimum
measure, the regulated small MS4 must
include the following five components:

*  Develop a storm sewer system map that
   shows  the location of all outfalls and the
   names and  locations of all waters of the
   United States that receive discharges
   from those outfalls

•  Prohibit, through ordinance or other
   regulatory mechanism, non-storm water
   discharges  into the storm sewer system
   and implement appropriate enforcement
   procedures and actions

•  Develop and implement a plan to detect
   and address illicit discharges to the MS4

•  Educate public employees, businesses,
   and the general public of hazards
   associated with illicit discharges and
   improper disposal of waste

•  Identify the appropriate best
   management practices and measurable
   goals for this minimum measure
                              Illicit Discharge Detection and Elimination: A Guidance Manual

                                                    Chapter 1: The Basics of Illicit Discharges
                               PHASE II HIGHLIGHTS

  Who must meet the requirements?       Selected small MS4s

  How many Phase II communities
  exist nationally?
  What are  the requirements related
  to illicit discharges?

  What is the deadline for meeting
  these requirements?
EPA estimates 5,000-6,000

Develop programs to prevent, detect
and remove illicit discharges

Permits issued by March 10, 2003.
Programs must be fully implemented by
the end of first permit term (5 years)
In the regulation, EPA recommends that the
plan to detect and address illicit discharges
include procedures for:

•   Locating priority areas likely to have
    illicit discharges (which may include
    visually screening outfalls during dry
    weather and conducting field tests of
    selected pollutants)

•   Tracing the source of an illicit discharge

•   Removing the source of the discharge

•   Program evaluation and assessment

1.4   Experience Gained in
Phase I

The Center for Watershed Protection
conducted a series of surveys and interviews
with Phase I communities to determine the
current state of the practices utilized in local
IDDE programs, and to identify the most
practical, low-cost, and effective techniques
to find, fix  and prevent discharges. The
    detailed survey included 24 communities
    from various geographic and climatic
    regions in the United States. Some of the key
    findings of the survey are presented below
    (CWP, 2002)4.

    •  Lack of staff significantly hindered
       implementation of a successful IDDE
       program. Phase I communities rely
       heavily on the expertise of their field
       staff—practical expertise that has been
       acquired over many years as programs
       gradually developed. Methods or
       approaches recommended for Phase II
       communities should be less dependent
       on professional judgment.
    4 Survey results are based on responses from 24
    jurisdictions from 16 states. Surveys were supplemented
    by on-site interviews of staff of eight IDDE programs:
    Baltimore City, MD; Baltimore County, MD; Boston Water
    and Sewer Commission (BWSC), MA; Cambridge, MA;
    Dayton, OH; Raleigh, NC; Wayne County, Ml; and Fort
    Worth, TX. Jurisdictions selected for the survey and
    interviews represent a variety of geographic and climatic
    regions. The EPA storm water coordinators for each region
    of the country were contacted for recommendations on
    jurisdictions to include in the survey. Also, a variety of
    jurisdiction sizes in terms of population, IDDE program
    service area, and land use was targeted.
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 1: The Basics of Illicit Discharges
   Clear and effective ordinance
   language should be adopted by Phase
   II communities to ensure that all
   potential sources of illicit discharges
   are prohibited, and that the community
   has sufficient legal authority to
   inspect private properties and enforce

   Many communities lacked up-to-date
   mapping resources, and found that
   mapping layers such as storm sewers,
   open drainage channels, waters of
   the U.S., outfalls, and land use  were
   particularly useful to conduct and
   prioritize effective field investigations.

   Outfall screening required the greatest
   staff and equipment resources,  and
   did not always find problem outfalls.
   Communities recommended a fast and
   efficient sampling approach that utilizes
   a limited number of indicator parameters
   at each outfall to find problem outfalls.
                  •   When purchasing equipment, Phase II
                     programs should communicate with
                     other jurisdictions to consider sharing
                     field equipment and laboratory costs.

                  •   Use of some discharge tracers has proven
                     challenging and sometimes fruitless,
                     because of false or ambiguous results
                     and complex or hazardous analytical
                     methods. Accurate, cost-effective, and
                     safe monitoring methods are needed to
                     effectively use tracers.

                  •   Municipal I DDE programs worked
                     best when  they integrated illicit
                     discharge control in the wider context
                     of urban watershed restoration. Table 3
                     provides some examples of how greater
                     interagency cooperation can be achieved
                     by linking restoration program areas.

                  In summary, survey  communities expressed
                  a strong need for relatively simple guidance
                  to perform illicit discharge investigations.
                  To address this need, the Manual has been
                  designed to make simple program and
                  technical recommendations for Phase II
                  communities to develop cost-effective IDDE
Illicit Discharge Detection and Elimination: A Guidance Manual

                                                 Chapter 1: The Basics of Illicit Discharges
Table 3: Linking Other Municipal Programs to IDDE Program Needs
Watershed-Related Program
Subwatershed Mapping and Analysis
Rapid Assessment of Stream
Watershed Monitoring and Reporting
Stream Restoration Opportunities
Watershed Education
Pollution Prevention for Generating
How Program Relates to IDDE Program Needs
• Mapping and aerial photography are critical tools needed for
illicit connection detection surveys. CIS tax map layers are
often useful to identify property ownership.
• Observations from physical stream assessments are often
useful in identifying problem areas, including dry weather flow
outfalls, illegal dumping, and failing infrastructure locations.
• Compiled water quality and other indicator data can be useful in
targeting problem areas.
• Stream restoration opportunities can often be coordinated with
sewer infrastructure upgrades and maintenance.
• Educating the public about unwanted discharges can save
programs money by generating volunteer networks to report
and locate problem areas. Better awareness by the public can
also reduce the likelihood of unintentional cross-connections.
• Providing incentives to businesses to inspect and correct
connections can save programs money.
Illicit Discharge Detection and Elimination: A Guidance Manual

                                              Chapter 2: Components of an Effective DDE Program
                 Chapter 2: Components of an  Effective
                                       IDDE  Program
         The prospect of developing and administering
         an IDDE program can be daunting, complex
         and challenging in many communities. This
         Chapter organizes and simplifies the basic
         tasks needed to build a program. In general,
         a community should consider eight basic
         program components, as follows:

         1. Audit Existing Resources and
         Programs- The  first program component
         reviews existing local resources, regulations,
         and responsibilities that bear on illicit
         discharge control in the  community. A
         systematic audit defines local needs and
         capabilities, and provides the foundation for
         developing the initial IDDE program plan
         over the first permit cycle.

         2. Establish Responsibility, Authority
         and Tracking- This component finds the
         right "home" for the IDDE program within
         existing local departments and agencies.
         It also establishes the local legal authority
         to regulate illicit discharges, either by
         amending an existing ordinance, or crafting
         a new illicit discharge ordinance. This
         program component also involves creation of
         a tracking system to report illicit discharges,
         suspect outfalls, and citizen complaints, and
         to document local management response and
         enforcement efforts.

         3. Complete a Desktop Assessment
         of Illicit Discharge Potential-  Illicit
         discharges are not uniformly distributed
         across a community, but tend to be clustered
         within certain land uses, subwatersheds, and
         sewage infrastructure eras. This program
         component helps narrow your search for
         the most severe illicit discharge  problems,
through rapid analysis of existing mapping
and water quality monitoring data.

4. Develop Program Goals and
Implementation Strategies- This program
component integrates information developed
from the first three program components to
establish measurable goals for the overall
IDDE program during the first permit cycle.
Based on these goals, managers develop
specific implementation strategies to improve
water quality and measure program success.

5. Search for Illicit Discharge Problems
in the Field- This component involves
rapid outfall screening to find problem
outfalls within priority subwatersheds.
Results of outfall surveys are then used
to design a more sophisticated outfall
monitoring system to identify flow types
and trace discharge sources. Many different
monitoring options exist, depending on local
needs and discharge conditions.

6. Isolate and Fix Individual Discharges-
Once illicit discharge problems are found,
the next step is to trace them back up
the pipe to isolate the specific source or
improper connection that generates them.
Thus, this program component improves
local capacity to locate specific discharges,
make needed corrections, and take any
enforcement actions.

7. Prevent Illicit Discharges- Many
transitory and intermittent discharges
are produced by careless practices at
the home or workplace. This important
program component uses a combination of
education and enforcement to promote better
         Illicit Discharge Detection and Elimination: A Guidance Manual
Preceding Page Blank

Chapter 2: Components of an Effective IDDE Program
pollution prevention practices. A series of
carrots and sticks is used to reach out to
targeted individuals to prevent illegal or
unintentional illicit discharges.

8. Evaluate the Program- The last
component addresses the ongoing
management of the IDDE program. The
measurable goals set for the IDDE program
are periodically reviewed and revisited
to determine if progress is being made,
or implementation strategies need to be

Within each program component, a
community has many options to choose,
based on its size, capability and the severity
of its illicit discharge problems. Chapters 3
through 10 address each IDDE program
component in more detail, and summarize
                        its purpose, methods, desired product or
                        outcome, and budget implications. The
                        remainder of each chapter provides program
                        managers with detailed guidance to choose
                        the best options to implement the program
                        component in their community.

                        Scheduling of the eight IDDE program
                        components is not always sequential and
                        may overlap in some cases. In general, the
                        first four program components should be
                        scheduled for completion within the first
                        year of the permit cycle in order to develop
                        an effective program for the remaining
                        years of the permit. Table 4 summarizes
                        the specific tasks and products associated
                        with each IDDE program component. The
                        scheduling, costs and expertise needed
                        for each IDDE program component are
                        compared in Table 5.
               Table 4: Key Tasks and Products in IDDE Program Implementation
 Program Component
             Key Tasks
 1. Audit existing
Infrastructure Profile
Existing Legal Authority
Available Mapping
Experienced Field Crews
Access to Lab Services
Education and Outreach Outlets
Discharge Removal Capability
Program Budget and Financing
  Agreement on Lead Agency
  5 year Program Development
  First Year Budget and Scope
  of Work
 2. Establish
   responsibility and
Review Existing Ordinances
Define "Illicit"
Provisions for Access/Inspections
Select Enforcement Tools
Design Tracking System
• Adopt or Amend Ordinance
• Implement Tracking System
 3. Desktop
   assessment of illicit
   discharge potential
Delineate Subwatersheds
Compile Mapping Layers/Data
Define Discharge Screening Factors
Screen Subwatersheds for Illicit Discharge
Generate Maps for Field Screening
• Prioritize Subwatersheds for
  Field Screening
 4. Develop program
   goals and
Community Analysis of Illicit Discharge
Public Involvement
• Measurable Program Goals
• Implementation Strategies
      Illicit Discharge Detection and Elimination: A Guidance Manual

                                    Chapter 2: Components of an Effective DDE Program
Table 4: Key Tasks and Products in IDDE Program Implementation
Program Component
5. Search for illicit
problems in the field
6. Isolate and
fix individual
7. Prevent illicit
8. Program evaluation
Key Tasks
• Outfall Reconnaissance Inventory (OKI)
• Integrate OKI data in Tracking System
• Follow-up Monitoring at Suspect Outfalls
• Implement Pollution Hotline
• Trunk and On-site Investigations
• Corrections and Enforcement
• Select Key Discharge Behaviors
• Prioritize Outreach Targets
• Choose Effective Carrots and Sticks
• Develop Budget and Delivery System
• Analyze Tracking System
• Characterize Illicit Discharges Detected
• Update Goals and Strategies
• Initial Storm Drain Outfall
• Develop Monitoring Strategy
• Maintain Tracking System
• Implement Residential,
Commercial, Industrial
or Municipal Pollution
Prevention Programs
• Annual Reports
• Permit Renegotiation
Table 5: Comparison of IDDE Program Components
IDDE Program
1. Audit
2. Authority
3. Desktop Analysis
4. Goals/Strategies
5. Field Search/Monitoring
6. Isolate and Fix
7. Prevention
8. Evaluation/Tracking
To Do It
Year 2 to 5
Year 2 to 5
Year 2 to 5
Type of Expertise
Stakeholder Management
Pipe and Site Investigations
Data Analysis
Key: $ = <$10,000
$$ = $10,000-25,000 ,,,,,! , , , r,-*r ป
$$$ = $25,000 - 50,000 % - Moderately Difficult
$$$$ = > $50,000 ???- Complex
2.1   Management Tips To
Develop an Effective IDDE

Every community will develop a unique
IDDE program that reflects its size,
development history, land use, and
infrastructure. Still, some common threads
run through effective and well-managed
local IDDE programs. Below are some tips
on building an effective local.
 1. Go after continuous sewage discharges
first. Effective programs place a premium
 on keeping sewage out of the storm drain
 system. Continuous sewage discharges
 pose the greatest threat to water quality and
 public health, produce large pollutant loads,
 and can generally be permanently corrected
 when the offending connection is finally
 found. Intermittent or indirect discharges are
 harder to detect, and more difficult to fix.
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 2: Components of an Effective IDDE Program
2. Put together an interdisciplinary and
interagency IDDE development team. A
broad range of local expertise needs to be
coordinated to develop the initial IDDE
plan, as indicated in Table 5. Effective
programs assemble an interagency program
development team that possesses the
diverse skills and knowledge needed for the
program, ranging from legal analysis, GIS,
monitoring, stakeholder management and
pipe repairs.

3. Educate everybody about illicit
discharges. Illicit discharge control is a
new and somewhat confusing program
to the public,  elected officials, and many
local agencies. Effective programs devote
considerable resources to  educate all three
groups about  the water quality impacts of
illicit discharges.

4. Understand your infrastructure. Finding
illicit discharges is like finding a needle
in a haystack on a shoestring budget.
Many indirect or transitory discharges are
extremely difficult to catch through outfall
screening. Therefore, effective programs seek
to understand the history  and condition of
their storm water and sewer infrastructure to
find the combinations that create the greatest
risk for illicit discharge. Effective programs
also screen land uses to locate generating
sites within targeted subwatersheds. For
example, knowing the proximity of the
infrastructure to the groundwater table or
knowing that the sewer collection system has
a long transit  time can influence the indicator
parameters and associated thresholds that a
community chooses to target.

5. Walk all of your streams in the first
permit cycle.  Perform a rapid Outfall
Reconnaissance Inventory (ORI) on every
mile of stream or channel in the community,
starting with  the subwatersheds deemed to
                  have the greatest risk. The ORI allows you
                  to rapidly develop an accurate outfall map
                  and quantify the severity of your discharge
                  problems. ORI data and field photos are
                  extremely effective in documenting local
                  problems. Stream walks and the ORI should
                  be conducted regularly as part of an IDDE
                  program. In many areas, it may require as
                  many as three stream walks to identify all
                  outfall locations.

                  6. Use GPS to create your outfall map. In
                  most communities, the storm water system
                  and sewer pipe networks are poorly mapped,
                  and consist of a confusing blend of pipes and
                  structures that were constructed in many
                  different eras. Effective programs perform
                  a field reconnaissance to ground truth the
                  precise locations of all outfalls using GPS
                  technologies. Effective programs have
                  learned to quickly evaluate outfalls of all
                  sizes, and not just major ones ( >36 inches in

                  7. Understand your discharges before
                  developing a monitoring plan. Monitoring is
                  usually the most expensive component of
                  any local IDDE program, so it is extremely
                  important to understand your discharges
                  before committing to a particular monitoring
                  method or tracer. Compiling a simple dis-
                  charge "fingerprint" library that character-
                  izes the chemistry of major flow types in the
                  community (e.g., sewage, septage, washwater,
                  groundwater, tap water, or non-target
                  irrigation water) is recommended. This
                  library can distinguish flow types and adjust
                  monitoring benchmarks.

                  8. Consider establishing an ambient (in-
                  stream) chemical and/or biological monitor-
                  ing program. Prioritizing outfall  screening
                  and investigation can save time in the field.
                  An ambient chemical or biological monitor-
                  ing program can provide supplemental
Illicit Discharge Detect/on and Elimination: A Guidance Manual

                                       Chapter 2: Components of an Effective IDDE Program
information to help prioritize sites and can
be used to document long-term success.

9,  Utilize a simple outfall tracking system, to
organize all your IDDE program data. Illicit
discharges  are hard enough to find if an
organized system to track individual outfalls
is lacking. Effective programs develop a
unified geospatial tracking system to locate
each outfall, and store information on its
address, characteristics, photos, complaints
and monitoring data. The tracking system
should be developed early in the permit
cycle so that program managers can utilize it
as an evaluation and reporting tool.

10. Outsource some IDDE functions to local
watershed groups. Staffing is the greatest
single line item expense associated with a
local IDDE program, although staffing needs
are often temporary or seasonal in nature.
Some effective programs have addressed
this staffing imbalance by contracting with
watershed groups to screen outfalls, monitor
stream quality, and handle storm water
education. This strategy reduces overall
program costs, and increases local watershed
awareness and stewardship.

11. Utilize a hotline as an education
and detection tool. Citizen hotlines are
a low-cost strategy to engage the public
in  illicit discharge surveillance, and are
probably the only effective way to pick up
intermittent and transitory discharges that
escape outfall screening. When advertised
properly, hotlines are also an effective tool
to  increase awareness  of illicit discharges
and dumping. Effective programs typically
respond to  citizen reports within 24 hours,
acknowledge their help, and send them storm
water education materials. When citizens play
a stronger role in reporting illicit discharge
problems, local staff can focus their efforts on
tracing the problem to its source and fixing it.
12. Cross-train all local inspectors to
recognize discharges and report them for
enforcement. Effective programs make sure
that fire, building, plumbing, health, safety,
erosion control and other local inspectors
understand illicit discharges and know
whom to contact locally for enforcement.

13. Target your precious storm water
education dollars. Most programs never
have enough resources to perform the
amount of storm water education needed to
reduce indirect and transitory discharges in
their community. Consequently, effective
programs target their discharges of concern,
and spend their scarce dollars in the
subwatersheds, neighborhoods or business
sectors most likely to generate them.

14. Stress public health and safety benefits
of sewage-free streams. Effective programs
publicize the danger of sewage discharges,
and notify the public and elected officials
about the discharges that need to be
prevented or corrected.

75. Calibrate your program resources to the
magnitude of the illicit discharge problem.
After a few years of analysis and surveys,
communities get a good handle on the actual
severity of their illicit  discharge problems.
In some communities, storm drains will be
relatively clean, whereas others may have
persistent problems. Effective programs are
flexible and adaptive, and shift program
resources to the management measure that
will reduce the greatest amount  of pollution.

16. Think of discharge prevention as a
tool of watershed restoration. Discharge
prevention is considered one  of the seven
primary practices used to restore urban
watersheds (Schueler,  2004). Effective
programs integrate illicit discharge control
as a part of a comprehensive  effort to restore
local watersheds.
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 2: Components of an Effective /DDE Program
28                         Illicit Discharge Detection and Elimination: A Guidance Manual

                                     Chapter 3: Auditing Existing Resources and Programs
                            Chapter 3: Auditing  Existing
                               Resources and  Programs
Purpose: This program component identifies
the most capable local agency to staff and
administer the IDDE program, analyzes
staffing and resource gaps, and searches for
all available local resources and expertise
that can be applied to the IDDE program.

Method: The key method used for this
program component is a local IDDE "audit,"
which consists of external research, agency
interviews, and interagency meetings to
determine existing resources and program
gaps. The audit typically looks at eight major
factors needed to build an IDDE program:

•  Profile of existing storm water and sewer
   infrastructure, as well as historical
   plumbing codes

•  Existing legal authority to regulate illicit

•  Available mapping data and GIS

•  Field staff availability and expertise

•  Lab/monitoring equipment and
   analytical capability

•  Education and outreach resources and

•  Discharge removal capability and
   emergency response

•  Program budgeting and financing
Desired Product or Outcome(s): The
desired outcome is an initial five-year IDDE
program development plan over the current
permit cycle. This will usually consist of an
internal agreement on the lead agency, an
initial scope of work, the first year budget,
and a budget forecast for the entire permit

Budget and/or Staff Resources Required:
The cost to conduct an audit depends on
the size of the community, the degree of
interagency cooperation, and the local
budget process. Plan for less than one staff
month for smaller communities, and up to
three staff months for larger ones.

Integration with Other Programs: The
audit is the best time to integrate the other
five minimum management measures
required under NPDES Phase II permits,
including public education and outreach,
public involvement, construction site runoff
control, post-construction runoff control,
and pollution prevention/good housekeeping
for municipal operations.
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 3: Auditing Existing Resources and Programs
3.1    Audit Overview

A community should conduct a quick
audit of existing and needed capacity when
developing its IDDE program. The audit
helps develop realistic program goals,
implementation strategies, schedules, and
budgets to comply with NPDES permit
requirements and improve water quality.
The audit consists of external research,
agency interviews and interagency
meetings to determine existing  resources
and program gaps. The audit examines
the community's current capabilities in
eight topic areas: infrastructure profile,
legal authority, available mapping, field
staff experience, access to monitoring
labs, education and outreach resources,
discharge removal capability, and
program budgets and financing.
                 Existing expertise is likely divided among
                 multiple agencies (see Table 6) that should
                 be contacted during the audit. Some of these
                 agencies can become important partners in
                 the development and implementation of the
                 IDDE program, and contribute resources,
                 program efficiencies and overall cost
                 savings. The first agencies to interview are
                 local emergency responders that already deal
                 with spills, accidents, hazardous materials
                 and sewage leaks that occur. In addition, it
                 is worth getting to know the local agency
                 responsible for plumbing code inspection
                 during construction.

                 Table 7 provides representative examples
                 of questions that the audit should ask to
                 determine the needs and capabilities of a
                 community associated with each program
Table 6: Potential Local Agencies and Departments to Contact During an Audit
Audit Topic
Infrastructure Profile
Existing Legal Authority
Available Mapping
Field Staff
Access to Lab Services
Education and Outreach
Discharge Removal
Program Budget and
• Water and Sewer Authority
• Public Works
• Planning Department
• Parks and Recreation
• Environmental Protection
• Public Works
• Local Streets/Utilities
• Public Works
• Environmental Compliance
• Development Review
• Public Works
• Local College or University
• Parks and Schools
• Water and Sewer Utility
• Fire, Rescue and Police
• Public Works
• Grants
• Fines
• Application fees
Agencies and Departments
• Public Works
• Local Health Department
• Road Engineering
• Fire, Police or Rescue (Hazardous
material responders)
• Planning and Zoning
• Emergency Responders
• Watershed Groups
• Fire, Building, Health and Code
• Drinking Water or Wastewater
Treatment Plant
• Private Contract Monitoring
• Health Department
• Community Liaison Office
• Civic and Watershed Groups
• Water and Sewer Utilities
• Private Plumbing Contractors
• Utility Fees
• Department Operating Budget
Illicit Discharge Detection and Elimination: A Guidance Manual

                                            Chapter 3: Auditing Existing Resources and Programs
      Audit Topics
                             Table 7: Potential IDDE Audit Questions
 Infrastructure Profile
•  How many miles of streams and storm drains exist in the MS4?
•  What is the area served by storm drains, sewers, and septics?
•  What is the general age and condition of the infrastructure?
 Existing Legal Authority
   Does an illicit discharge ordinance already exist?
   Does effective inter-departmental coordination and cooperation currently
   Is there an existing reporting and tracking system (e.g., hotline)?
   Is the municipality involved with industrial storm water NPDES permit
   activities or pre-treatment programs?
 Available Mapping Data
•  Does current CIS data exist and does it include coverage of sanitary and
   storm sewer networks?
•  Is there a centralized location for the data?
•  Are digital and hardcopy versions of mapping data readily available?
 Field Staff
• Are municipal staff available to walk stream miles and record information?
• Do municipal staff have the training and expertise to lead a field team?
• Are basic field supplies already owned by the municipality and available for
 Access to Lab Services
   Does the municipality have access to an analytical laboratory?
   Is there a local university or institution that might be a willing partner?
   If yes, is the existing equipment and instrumentation considered to be safe,
   accurate and reliable?
   Are experienced municipal staff available to conduct analytical analyses?
   Does the lab and staff have the capability to conduct more sophisticated
   special studies?
 Education and Outreach
   Does the community already have an Internet website to post outreach
   Are there regular community events that can be used to spread the
   Are good inter-agency communication mechanisms in place?
   Do outreach materials on illicit discharges already exist?
 Discharge Removal
  Who currently responds to spills, overflows and hazardous material
  Are municipal staff properly equipped and trained to repair most common
  types of illicit connections?
  Does the municipality have clear authority identifying responsible parties?
  Is there a response time commitment to known and reported problems?
  Is there a list of pre-approved contractors to perform corrections?
 Program Budget
 and Financing
   Is there a dedicated annual budget line item planned for the IDDE program?
   Are there cost-share arrangements/opportunities available with other
   Have grant awards been awarded to the municipality for special studies
   associated with watershed restoration in the past?
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 3: Auditing Existing Resources and Programs

The first part of the audit profiles current
and historic storm water and sewer
infrastructure in the community. The
basic idea is to get a general sense  of the
magnitude of the task ahead, by looking at
the size, age and condition of the storm drain
system (and the sewers within the MS4
as well). Some useful planning statistics

•   Number of storm drain outfalls

•   Miles of storm drain pipe

•   Total stream and channel miles

•   Total area serviced by storm drains

ซ   Total area serviced by sewers

ซ   Total area serviced by septic systems

These statistics are extremely helpful in
getting a handle on the total effort  required
to assess the overall system. Any data on the
nature and age of storm drains and sewers
can be useful (e.g., open vs. enclosed, young
vs. old). The basic infrastructure statistics
can be generated from a quick analysis of
infrastructure and topographic maps. At
this stage, ballpark estimates are fine; more
detailed estimates can be developed later in
the desktop analysis component.

It is also worth examining historic
plumbing codes to determine what kinds
of connections were allowed in the past.
                  Often, interviews with "old-timers" who
                  remember past building codes and practices
                  can provide insights about historical
                  construction as to where illicit connections
                  may be a problem.


                  This part of the audit examines whether a
                  community currently has adequate legal
                  authority to regulate illicit discharges
                  through the following actions:

                  ป   Evaluate and modify plumbing codes5

                  ป   Prohibit illicit discharges

                  ป   Investigate suspected illicit discharges

                  ป   Require elimination of illicit discharges

                  ป   Carry out enforcement actions

                  The audit of existing legal authority
                  entails a search and review of all existing
                  ordinances that could conceivably bear on
                  illicit discharge control, and interviews with
                  the agencies that administer them. Some
                  common local ordinances that may address
                  illicit discharges are outlined in Table 8.
                  Many communities already have regulations
                  prohibiting specific illicit discharges, such
                  as hazardous chemicals, litter or sewage.
                  Often, public health  ordinances may
                  prohibit certain sewage discharges. Local
                  utilities may have plumbing codes and staff
                  capability to track down  and remove illicit
                  connections on the system they operate.
                                                 5 In some states such as NC, plumbing codes are
                                                 established through a state process. In these cases, local
                                                 governments typically need specific authority to adopt
                                                 any local modifications, which can be difficult to obtain. In
                                                 such states, it may be prudent for the storm water program
                                                 managers of several local governments to organize as a
                                                 single cooperative group to modify codes at the state level.
Illicit Discharge Detection and Elimination: A Guidance Manual

                                         Chapter 3: Auditing Existing Resources and Programs
                 Table 8: Codes and Ordinances with Potential Links to IDDE
       Fire codes
       Hazardous wastes/spill controls
       Health codes
       Industrial storm water compliance
       Litter control regulations
       Nuisance ordinances
       Plumbing codes
Pollution prevention permitting requirements
Restaurant grease regulations
Septic system regulations
Sewer/drain ordinances
Storm water ordinance
Street/highway codes
To establish legal authority, communities
will need to either develop a new IDDE
ordinance or modify an existing ordinance
that addresses illicit discharges. Language
from existing ordinances that addresses
illicit discharges should be incorporated
or cross-referenced into any new IDDE
ordinance to minimize conflicts and
confusion. Furthermore, existing code
ordinances may need to be amended or
superceded to be consistent with the new
IDDE ordinance.

In some instances, communities may want
to consider collaborating with neighboring
or nearby  MS4s to develop ordinance
language and legal authority, particularly if
they share a common receiving water. Non-
municipal permittees such as Departments
of Transportation and special districts may
also look to collaborate with municipal
MS4s when considering ordinance language
and legal responsibility.


The third part of the  audit looks at the
coverage and quality of mapping resources
available to  support the IDDE program.
Specifically, efforts should be made to
see if a Geographic Information System
(GIS) exists, and what digital mapping
layers it contains. If a community does
not possess a GIS, a community may
choose to  establish one (which can be quite
expensive), or rely on available hardcopy
maps. GIS and hardcopy maps are frequently
available from the following local agencies:
planning, tax assessment, public works,
parks and recreation, emergency response,
environmental, transportation, utilities,
or health. If a watershed extends beyond
the boundaries of a community, it may be
necessary to acquire mapping data from
adjacent communities.

Non-local sources of mapping data include
state and federal agencies and commercial
vendors. EPA and state environmental
regulatory agencies maintain lists of NPDES
dischargers; Comprehensive Environmental
Response, Compensation, and Liability Act
(CERCLA) sites; Resource Conservation
and Recovery Act (RCRA) sites; and other
industrial or hazardous material discharge
sites. These sites are readily  available as
GIS layers6. Commercial vendors are good
sources for low-altitude aerial photos of your
community. These can be expensive but are
often the best way to get a high-resolution
recent 'snapshot' of the jurisdiction. Chapter
5 presents more detail on mapping layers
needed for an IDDE program.

3.5                   of Field Staff

Field staff play a critical role in any
IDDE program as they walk streams,
assess outfalls, collect samples, respond
to discharge complaints, and handle
6 Some readily available GIS layers provided by regulatory
agencies can be incomplete and inaccurate (particularly with
location information). Communities should use their IDDE
program and the associated data collection efforts to update
their local information associated with these databases.
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 3: Auditing Existing Resources and Programs
enforcement. This part of the audit evaluates
the availability of local staff to perform
these functions, and their training needs.
Phase I communities report that experienced
field staff are a major factor in IDDE
program success.

Experienced staff can be supplemented
with support staff such as interns and local
watershed groups, if they are properly
trained (CWP, 2002). As part of the  audit,
program managers should investigate
whether existing staff can be used or
whether new hires are anticipated, and
explore intern  opportunities with local
universities and community colleges. Any
local staff with experience in water quality
sampling or development inspection should
be identified. Fire, building, health, safety
and erosion control inspectors are all
potential field crew draftees.

An initial estimate of the staff time needed
for field crews should be made at this time.
Phase I IDDE programs allocated a median of
1.0 person-year for field investigations, with
a range of 0.1 to  10 person-years each year
(CWP, 2002).  Several communities utilized
interns to assist with field monitoring and
office work. Since many IDDE surveys are
short term and seasonal, several communities
hired or transferred employees to serve on
field crews on  a temporary basis. Many
Phase I programs found it hard to precisely
quantify  actual staff time dedicated to IDDE
field work because  staff were assigned from
many departments, or performed other
unrelated tasks (building inspections, erosion
and sediment control inspections, etc.).

3.6              tO

This part of the audit identifies the best
options for laboratory analysis of water
quality samples collected in the field. Four
                  basic options exist to get access to laboratory
                  services, including:

                  1.  Contract services from a private lab

                  2.  Use existing lab facilities at local
                     drinking water or wastewater treatment

                  3.  Partner with a local water and sewer
                     district, university or community college

                  4.  Develop your own "in-house"
                     monitoring and lab capability

                  The last three options may require
                  purchasing special monitoring analysis
                  equipment, depending on the water
                  quality indicators ultimately selected. If a
                  community is considering developing "in-
                  house" monitoring capabilities, it will need
                  to address quality control, training needs,
                  safety, and hazardous waste disposal.  At this
                  point, a community simply wants to acquire
                  data on costs, indicator parameters, quality
                  control, and  experience for each of the
                  options being evaluated. Chapter 12 provides
                  more detail on factors  to consider when
                  selecting lab analysis options.


                  The next part of the audit looks at existing
                  educational and outreach resources  in the
                  community.  To begin,  look for other groups
                  that are  already involved in storm water
                  or watershed education, including parks,
                  schools, watershed groups, utilities  and any
                  other agencies performing this role. Next,
                  look for the current tools the public can use
                  to report water quality problems, such as
                  complaint hotlines, websites or community
                  liaison offices. When these exist, it  may be
                  possible to "piggy back" illicit discharge
                  reporting at little additional cost. If reporting
                  tools do not exist, program managers  should
                  look for opportunities  to share start-up costs
Illicit Discharge Detection and Elimination: A Guidance Manual

                                        Chapter 3: Auditing Existing Resources and Programs
with other agencies that may stand to benefit
from improved community interaction (e.g.,
erosion and sediment control, sanitary sewer
overflows, abandoned cars, etc.).

The audit should also look at community-
wide events and education outlets to spread
the IDDE message, such as fairs, festivals,
earth day events, school presentations,
and homeowner association meetings.
For a complete review of how to craft an
effective outreach and education plan,
consult Pollution Source Control Practices
(Schueler et al., 2004). Excellent education
and outreach materials have already been
developed by Phase I communities that are
available at little  or no cost (see Chapter
9). Program managers should consult these
resources and modify them as needed to
meet their local needs.


This part of the audit evaluates local
capacity to locate specific discharges, make
needed corrections or repairs, and take any
enforcement actions. These responsibilities
are frequently split among several local
agencies. For example, spills are often
handled by the fire department hazmat
response team, whereas dumping may be
enforced by public works. Communities
should always coordinate their IDDE
program with any experienced hazmat
response teams that exist. Similarly,
local water and sewer utilities or private
contractors that are in the business of
repairing pipes should always be consulted.
Their experience in specialized techniques
such as dye or video testing of pipe interiors
is essential for many illicit discharge source
investigations. Alternatively, communities
can opt to contract out many of these
Illicit discharges often occur due to "bad
plumbing" connections. Therefore, the audit
should identify key building inspectors to
determine what, if any, procedures are in
place to prevent these deficiencies. Lastly,
where corrections to plumbing are required,
communities should maintain a list of
"pre-approved"  plumbing contractors that
can promptly and professionally repair the

To ensure coordination, an up-to-date
tracking system should be shared among all
agencies involved.


The last part of  the audit explores how
much the local IDDE program will cost,
and how it will be funded. This section
provides some general budgeting guidance
on the costs to expect for the eight program
components. Overall IDDE program costs
vary depending on the severity of the
illicit discharge  problem, the size  of the
community (and storm drain systems),  and
the IDDE program choices you make.

Planning level budget estimates can be
derived for the eight IDDE program
components in three ways. The first way is to
look at the cost of IDDE program compliance
for Phase INPDES communities. These costs
were assessed in a CWP (2002) survey,  and
can be used to budget overall annual costs
for an IDDE program. Table 9 summarizes
median program costs for selected Phase
I IDDE program activities. The second
technique is to construct unit cost budgets
for each program component, based on an
assumed level of effort. The third technique
relies on EPA's overall average estimate of
compliance costs for Phase II IDDE program
of $1.30 per capita (with a staggering range
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 3: Auditing Existing Resources and Programs
Phase IIDDE Program Costs

The bulk of the cost for most IDDE
programs is related to staffing - typically,
about 75% of the total budget. Equipment
costs were fairly reasonable, with programs
spending a median of $1,000 on office
computers and software, and about $4,000
on field equipment. Many equipment
costs can typically be shared across other
community programs. Lab costs, for either
the purchase of lab equipment or the cost
associated with sending samples to labs,
were as high as $87,000 annually, with a
median of $8,000. Finally, most programs
had additional budgets for "other" which
included items such as education, training,
travel, consultants, and contractors.

It is worth noting that program costs
presented in Table 9 do not reflect
expenditures associated with special
investigations, which may be pursued by
                 communities to isolate specific sources
                 or test new methods or the direct costs to
                 fix problem connections. However, five
                 communities provided data on typical
                 correction costs, with an average cost of
                 $2,500 per correction (Table 10).

                 Estimated Phase II IDDE Program
                 Unit Cost

                 Cost estimates for the eight IDDE program
                 components are outlined in Table 11;
                 more detailed guidance on budgeting
                 for individual program components is
                 provided in subsequent chapters. Under
                 this presentation of cost, data, staff,
                 equipment, and supply costs are combined
                 and incorporated into a primary program
                 element, such as conducting an outfall
                 reconnaissance inventory. This approach
                 assumes a hypothetical scenario of stream/
                 MS4 miles and outfalls to investigate (see
                 Table 11 notes).
Table 9: Summary of Annual Phase 1 IDDE Program Costs
Program Element
Office Equipment (Computer/Software)
Field Equipment
Lab Equipment/Testing
Median Annual Cost
Table 10: Average Correction Costs
Cambridge, MA
Boston, MA
Knoxville, TN
Raleigh, NC
Springfield, MO
Average Cost Per Correction
Illicit Discharge Detection and Elimination: A Guidance Manual

                                     Chapter 3: Auditing Existing Resources and Programs
Table 11: IDDE Program Costs
IDDE Program Component
Component 1:
Component 2:
Component 3:
Component 4:
Component 5:
Component 7:
Component 8:
a) Perform Audit
b) Initial Program Plan
a) Adopt Ordinance
b) Tracking System
a) Desktop Analysis
b) Field Mapping
a) Develop Goals
b) Field Monitoring Strategy
a) Outfall Reconnaissance
Inventory (ORI)
b) Establish Hotline
c) Sample Analysis
d) Outfall Map
a) Isolate
a) Education
b) Enforcement
a) Program Administration
Start Up Cost
Annual Cost
Notes: NA = Not Applicable
Component 1 -Audit assumes $25/hr, 120 hours for low and 360 hrs for high. Program plan assumes 40 hrs for low and
120 hrs for high.
Component 2- Ordinance low cost from Reese (2000), high cost from CWP (1998) adjusted and rounded for inflation (2002 $).
Tracking system low cost assumes 40 hrs of development and $1 K of equipment for start up. Annual cost for low assumes 40
hrs per year. High estimates are adapted from Reese (2000) and assume 200 hrs for development and $3k for equipment at
start-up. High annual costs assume 100 hrs per year.
Component 3- Desktop analysis assumes 1 week for low and 4 weeks for high. Mapping costs assume paper maps (CWP,
1998) under low and CIS under high (40 hrs)
Component 4- Goals and strategies take 2 weeks for low and 6 weeks for high. Assume even split in time between two tasks.
Component 5-
a) ORI costs are from Ch 11 and assume 10 miles with 2-person crew for low and 20 miles with 3-person crew for high. ORI
costs assume work completed in one year, but not necessarily every year (permit cycle cost).
Low hotline costs are adapted from Reese (2000). High costs are from CWP research. Low annual costs assume an increased
volume of calls due to advertisement and assume 50 hours per year dedicated to this plus annual training.
Sample analyses are from various sources and are presented in Chapter 12. Estimates based on 80 samples per year for
both (shown as annual cost). Low start up costs are based on contract lab arrangements. High start up costs assume flow
type library is developed for eight distinct flow types. Low annual costs assume in-house analysis for Flow Chart Method
parameters. High annual costs assume contract lab analysis for 11 parameters.
Outfall map costs are same as the component 3 mapping task
Component 6- Isolate and fix have no assumed start up costs and are both vary depending on the community conditions. Low
annual isolation costs assume a one day investigation by a 2-person team per incident ($400) and four incidents per year plus
$400 in equipment and supplies. High assumes one incident per month. Estimates include on-site inspections. Fix costs are
from average costs from Phase I survey and assume same number of incidents as isolate. These costs can often be passed on
to responsible parties.
Component 7- Education estimate adapted from Reese (2000) and assumed to be 1/3 of total Phase I education budget.
Some adjustments were made based on assumptions by CWP.
Component 8- Low assumes 1/6 FTE, high assumes 1/4 FTE at an annual salary of $60K.
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 3: Auditing Existing Resources and Programs
Financing an IDDE Program

Once the initial budget has been estimated,
the next step is to investigate how to pay
for it. A full discussion of how to finance
local storm water management programs
is beyond the scope of this manual, but it is
worth consulting APWA (2001). The most
common financing mechanisms include:

•  Operating budgets

•  Debt financing

•  State grants and revolving loans

•  Property assessments

•  Local improvement districts

•  Wastewater utility fees

•  Storm water utility or district fees

•  Connection fees

•  Plan review/inspection fees

•  Water utility revenues

Of these, storm water utilities or districts
are generally considered one of the best
dedicated financing mechanisms. Some
useful resources to consult to finance your
local storm water programs include the

•  An Internet Guide to Financing Storm
   Water Management. 2001

•  Establishing a Storm Water Utility

•  Florida Association of Storm Water
•  How to Create a Storm Water Utility

•  The Storm Water Utility: Will It Work in
   Your Community?
   www. Oil _utility.html

3.10  The Initial IDDE Program

The local IDDE audit reveals resource gaps,
and expertise and staffing needed to build an
effective IDDE program. The next step is to
organize how you plan to phase in the eight
program components over the permit cycle.
The process results in the development of
an initial IDDE program plan that normally
includes five elements:

•  Overall schedule for plan
   implementation, with milestones

•  Detailed work plan for the first year

•  Budget for the first year

•  Five-year budget forecast

•  Process for gaining approval for first-
   year budget

Program managers  should consult the
next seven chapters for more guidance on
planning and budgeting individual IDDE
program components.
                             Illicit Discharge Detection and Elimination: A Guidance Manual

                                   Chapter 4: Establishing Responsibility and Legal Authority
                                 Chapter 4:  Establishing
                        Responsibility and Legal  Authority
Purpose: This program component is where
the legal and administrative authority is
established to regulate, respond and enforce
illicit discharges in the community. The
component also reviews local plumbing
codes to ensure that inappropriate
connections are prohibited, and develops a
tracking system to locate illicit discharges
and track management response.

Method(s): Several methods are used
to implement this program component,
including development of a new or amended
illicit discharge control ordinance and the
creation of a relational computer database
for internal and external tracking of illicit

Desired Product or Outcome(s):

a) Pass or amend a local ordinance that
   defines the  lead regulatory agency,
   defines the  range of illicit discharges to
   be covered, and specifies the range of
   enforcement mechanisms.

b) Establish an internal and external
   reporting and tracking system. The
   internal system is structured around the
   training/education of municipal staff
   to define and facilitate appropriated
   response and enforcement procedures.
   An external system or hotline links
   to the internal system and assists in
   response and enforcement by providing
   access to the public for reporting.

Budget and/or Staff Resources Required:
Establishing responsibility, legal authority
and an effective tracking system can take as
little as a month of staff effort to complete if
no major surprises or unforeseen costs are
encountered in the process. However, the
actual time-frame to adopt an ordinance or
fund a response system, for example, is often
much longer, given the crowded schedules
of elected officials and timing of the local
budget processes. Adoption of the ordinance
and the actual budget authorization may
require multiple votes over many months or
years. Continuous engagement and education
of key advisors, agency staff and elected
officials are needed throughout the effort.
Where hotlines exist (covering a range of
municipal functions), significant staff and
infrastructure savings should be realized.
The primary hurdle in this instance will be
employee training and education.

Integration with Other Programs: Public
education to advertise the hotline and
municipal training to educate employees
across departments and agencies are
the primary areas where this program
component can be integrated with other
community-wide initiatives. The hotline
can be used to report other watershed
and water quality problems (e.g., ESC,
dumping, sanitary sewer overflows). Good
coordination should occur between tracking
repair costs and determining appropriate
fine levels for enforcement purposes.

Three critical decisions are needed to
implement this program component—
what local agency will be responsible for
administering the IDDE program, will it
have adequate legal authority to do its job,
and how will illicit discharges be tracked.
Guidance is offered below to help program
managers make these decisions.
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 4: Establishing Responsibility and Legal Authority

For most communities, the IDDE program
will be established under the same agency
or department that oversees all other MS4
NPDES requirements (e.g., Department of
Environmental Protection, Department of
Public Works, Department of Health, etc.).
For small communities, IDDE program
administration and implementation may be
wrapped into the broad duties  of just a few
staff. For larger communities,  or where there
are  significant known problems associated
with illicit discharges, a community may
elect to have a dedicated department division
with core staff. In either event, the agency
and individuals responsible for the program
should be well identified along with a clear
understanding of program purpose, goals
and actions.

Other local departments may already have
authority over certain aspects of illicit
discharges. Therefore, close coordination and
communication with different  departments
is essential, and consideration  should be
given to consolidating responsibilities and
authority. If consolidation is not pursued,
regular inter-departmental briefings, training
sessions, and data sharing will enhance
program effectiveness and reduce the
likelihood of significant lag times between
discovery of a discharge and enforcement
or correction  due to split responsibilities
between departments.

In some cases, communities may want to
consider collaborating with adjacent or
nearby permittees in order to form a regional
approach to addressing illicit discharges.
This might be appropriate in situations where
municipalities share a common receiving
water, and program implementation is
conducted on a watershed management basis.

                  A community must demonstrate that it has
                  adequate legal authority to successfully
                  implement and enforce its IDDE program.
                  In fact, establishing legal authority is one
                  of the required components identified in
                  Phase II regulations, and can be identified
                  as a measurable goal. Guidance is provided
                  below on how to develop an IDDE ordinance
                  to establish legal authority.


                  Communities with illicit discharge
                  prohibitions in place have typically invoked
                  legal  authority using one or more of three

                  1.  Storm water ordinance that prohibits
                     illicit discharges to the drainage network
Plumbing code that prohibits illicit
connections to the drainage network

Health code that regulates the discharge
of harmful  substances to the drainage
                  A few concerns arise with the second and
                  third mechanisms. One example is plumbing
                  codes that only prohibit illicit connections
                  fail to  address other common discharges,
                  such as indirect discharges, illegal dumping,
                  or failing infrastructure. Similarly, exclusive
                  reliance on health codes to regulate illicit
                  discharges may not pick up discharges that
                  are not harmful to human health, such as
                  groundwater or potable water infiltration
                  and residential  irrigation return flows. With
                  some revision and expansion, one or all of
                  these existing mechanisms can meet the
                  needs of the IDDE program. Alternatively,  a
                  new, stand-alone illicit discharge ordinance
                  can be developed that supercedes all other
                  related codes.
Illicit Discharge Detection and Elimination: A Guidance Manual

                                  Chapter 4: Establishing Responsibility and Legal Authority
                                   CASE STUDY
  The City of Raleigh is an NPDES Phase I community. The Water Quality Group (WQG)
    within the Public Works Department oversees the City's illicit discharges program.
   The WQG was created in the early 1990s to be responsible for surface water quality
  across the City and to ensure compliance with the City's NPDES permits. Prior to that,
        various departments within city government handled water quality issues.

   Raleigh's Illicit Discharge Ordinance was adopted in the second year of their original
   NPDES Phase I permit. The ordinance clearly defines and prohibits illicit discharges
   and illicit connections; requires containment and clean-up of spills/discharges to, or
   having the potential to  be transported to, the storm drain system (it is also standard
    operating procedure that the City fire chief be notified of any spills immediately);
     allows for guaranteed right of entry for inspection of suspected discharges and
   connections; and outlines escalating enforcement measures, including civil penalties,
                         injunctive relief, and criminal penalties.

    Although the WQG runs the IDDE program, some functions are undertaken by the
  City's Public Utilities Department (e.g., fixing problems in the sanitary line, conducting
                dye and smoke testing, television inspection of the lines).

   Raleigh began with a flat annual IDDE budget based on their past experience of what
  the program costs to run. More recently, the program began receiving additional funds
   from the City's storm water utility. A portion of the budget is allocated for testing.
   Cleaning and correction costs are funded through various budgets depending on the
   illicit discharge source. The WQG also budgets for two specialists: one is responsible
   for enforcement and dealing with citizen complaints and the other is responsible for
   monitoring and tracing the source of problems. The cost of television inspection and
           smoke testing is included in the Public Utilities Department budget.
                             Source: Senior (2002, 2004)
The length and complexity of an IDDE            •   Investigate suspected illicit discharges
ordinance is largely a local community
decision. Appendix B provides a model            *   Recluire and enforce elimination of illicit
ordinance that may be adapted to meet the            discharges
specific needs of local communities.               .   Address unique conditions or
Some key components that should be
addressed to ensure full authority to prevent
and correct illicit discharges include the

•  Prohibit illicit discharges
Illicit Discharge Detection and Elimination: A Guidance Manual                           41

Chapter 4: Establishing Responsibility and Legal Authority

An IDDE ordinance should clearly define
and/or identify illicit discharges and clearly
state that these discharges are prohibited.
Some communities may prefer to provide a
short, concise definition of illicit discharges,
while others may wish to list specific
substances or practices that qualify as illicit
discharges. However, if a detailed list is
provided in the ordinance, a qualifying
statement should follow in order to include
polluting discharges not specifically listed.

Illicit connections should also be defined in
the ordinance. These connections include
pipes, drains, open channels, or  other
conveyances that have the potential to allow
an illicit discharge to enter the storm drain
system. The prohibition of illicit connections
should be retroactive to include  connections
made in the past, whether or not the
connection was permissible at the time. This
is especially important if historic plumbing
codes or standards of practice allowed for
connection of laterals and drains (e.g., shop
floor drains) to the MS4.

Lastly, the ordinance should identify
categories of non-storm water discharges or
other flows to the MS4 that are not considered
illicit. For example, the Phase II  rule exempts
discharges resulting from fire fighting
activities. Other activities that are commonly
exempt include discharges from dye testing
and non-storm water discharges permitted
under an NPDES permit, provided that the
discharger is in full compliance  with the
permit. The following categories of non-storm
water discharges  do not need to be addressed
in the IDDE program unless the operator of
the regulated small MS4 designates them as
significant contributors of pollutants:

•  Water line flushing

•  Landscape irrigation
                  •  Diverted stream flows

                  ป  Rising ground waters

                  ป  Uncontaminated ground water infiltration

                  ป  Uncontaminated pumped ground water

                  •  Discharges from potable water sources

                  •  Foundation and footing drain water

                  •  Air conditioning condensation

                  ซ  Irrigation water

                  ซ  Springs

                  ซ  Water from crawl space pumps

                  •  Lawn watering

                  •  Individual residential car washing

                  •  Flows from riparian habitats and

                  In some cases, communities will need to
                  assess unique local discharges of concern
                  and ensure that they are properly addressed
                  within the ordinance. Examples of unique
                  conditions or requirements sometimes
                  included in IDDE ordinances are septic
                  system provisions, plumbing codes, point of
                  sale dye testing, and pollution prevention plan
                  requirements for certain  generating sites.


                  Although many communities report that
                  most property owners cooperate when asked
                  for access for illicit discharge investigations,
                  this should never be taken for granted.
                  Indeed, the right of access to private property
                  for inspections is an essential provision of
                  any IDDE ordinance. The ordinance should
                  provide for guaranteed right of entry in case
                  of an emergency or a suspected discharge or
                  at any time for routine inspections, such as
                  dye or smoke tests.
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                                    Chapter 4: Establishing Responsibiiity and Legal Authority
The ordinance should also clarify that
right of entry applies to all land uses in the
community, and that proof of discharge
is not required to obtain entry. It should
also state the responsibility of the property
owner to disarm security systems and
remove obstructions to  safe and easy access.
Enforcement actions should be  established
for property owners that refuse access,
including the  ability to obtain a search
warrant through the court system.


An I DDE ordinance should define a range
of enforcement tools so the responsible
agency can effectively handle the wide
range of illicit discharge violations it is
likely to encounter. Potential  enforcement
tools can range from warnings  to criminal
prosecution. The choice of enforcement
tools should be based on volume and type of
discharge, its  impact on water quality and
whether it was intentional or  accidental.  In
addition, it is  helpful to spell  out the specific
activities that trigger progressively greater
enforcement.  Table 12 summarizes the range
of enforcement tools that have been used by
communities  to respond to illicit discharges.
The ordinance should provide for escalating
enforcement measures to notify operators
of violations and to require corrective
action. Voluntary compliance should be
used for first-time, minor offenders, while
more serious violations or continued non-
compliance may warrant a more aggressive
enforcement approach. Finally, the ordinance
should include methods for appeal to provide
owners with avenues for compliance.


Communities need to develop tracking
and reporting systems to support the entire
IDDE program, including enforcement. A
relational database with geospatial features
provides the greatest flexibility to cover
multiple program objectives. From a legal
standpoint, tracking systems are important
for historical documentation of problems
and corrective actions. More details on
designing and operating a tracking system
are described in subsequent chapters.
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Chapter 4: Establishing Responsibility and Legal Authority
Table 12: Summary of IDDE-Related Enforcement Tools
Type of Enforcement Action
Written Warning with
Voluntary Compliance
Written Notice of Violation
Ordering Compliance
Administrative Penalties
Civil Penalties
Compensatory Action
Criminal Prosecution
Cost of Abatement of the
Violation/Property Liens
Emergency Cease and
Desist Order
Suspension of Water or
Sewer Service
Stop Work Order
• Applies to first time, minor violations (Field staff should have
authority to do this)
• Should clearly state description of remedial measures necessary,
time schedule, penalties assessed if it doesn't happen, and timeframe
for appeal
• Daily financial penalty imposed by a responsible department for each
day violation remains unfixed
• Daily financial penalty imposed by judicial authority for each day
violation remains unfixed
• In lieu of enforcement proceedings or penalties, impose alternative
compensatory action, e.g., storm drain stenciling, etc.
• Applies to intentional and flagrant violations of ordinance
• Each day discharge continues is typically a separate offense
• Can result in fines and imprisonment
• Applies when jurisdiction remedies the discharge or conducts cleanup,
but may also be used to recoup administrative costs
• May constitute a property lien if not paid within certain timeframe
• Applies when ordinance continues to be violated
• Requires immediate compliance with ordinance by halting operations/
terminating discharges
• May be a written or verbal order to remove illicit discharge
• Applied in emergency situations to immediately discontinue
discharge to MS4
• May be applied as enforcement measure when property owner does not
comply/fix the problem within timely manner
• Typically applies to discharges associated with construction activity
• No further work can be done until compliance is achieved
Illicit Discharge Detection and Elimination: A Guidance Manual

                                Chapter 5: Desktop Assessment of Illicit Discharge Potential

                       Chapter  5:  Desktop Assessment of
                                Illicit Discharge Potential
Purpose: This program component uses
mapping and other available data to
determine the potential severity of illicit
discharges within a community, and
identifies which subwatersheds or generating
land uses merit priority investigation.

Method(s): A simple desktop assessment
method can rapidly determine the severity of
illicit discharge problems in a community. If
an MS4  has fewer than 20 stream miles, this
component can be skipped and a community
can proceed directly to an ORI. The desktop
assessment method has five basic elements:

1.   Delineate subwatersheds or other
    drainage units within your community

2.   Compile available mapping and data for
    each drainage unit (e.g.,  land use, age,
    outfalls, infrastructure history)

3.   Derive subwatershed discharge
    screening factors using GIS analysis

4.   Screen and rank illicit discharge
    potential at the subwatershed and
    community level

5.   Generate maps to support field

Desired Product or Outcome(s): The
desktop  assessment is used to guide initial
field screening, and support  initial IDDE
program decisions. Key outcomes include:

a)   Screening problem catchments or

b)   Creation of GIS or other database system
    to track outfalls
c) Gaining an overall assessment as to the
   severity of illicit discharge problems in
   the community

d) Generation of basic mapping for
   subsequent field work

Budget and/or Staff Resources Required:
The initial desktop assessment of illicit
discharge potential should not be a long
or arduous process, and should generally
take less than four staff weeks. The quality
and accuracy of the desktop assessment,
however, will vary depending on the extent
of available mapping information and GIS
data. If mapping information is poor, the
desktop assessment should be skipped, and
program managers should go directly to the
field to inventory outfalls.

Integration with Other Programs: If the
desktop assessment suggests few potential
illicit discharge problems, program
managers may want to combine outfall
surveys with broader stream corridor
assessment tools such as the Unified Stream
Assessment (Kitchell and Schueler, 2004).
The desktop  assessment provides insight
on how to narrow your illicit discharge
search, and is helpful when designing a
discharge tracking system to best suit your
needs. Finally, the desktop assessment can
identify subwatersheds, generating sites, and
neighborhoods where storm water education
should be targeted to address illicit discharge
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 5: Desktop Assessment of Illicit Discharge Potential
5.1                Of

A community should understand the extent
of water quality problems caused by illicit
discharges. The desktop assessment should
not be a time-consuming research effort,
but should draw on existing background
data and anecdotal information to initially
characterize illicit discharge potential at the
subwatershed level.

Subwatersheds are then screened based on
their composite score, and are designated as
having a low, medium or high risk:

•  Low - no known illicit discharge
   problems in the subwatershed

ซ  Medium - problems are confined to a
   few stream reaches, outfalls or specific
   generating sites in the subwatershed

ซ  High - Problems are suspected to be
   severe throughout the subwatershed

The desktop assessment also  shapes the
overall direction of a local IDDE program.
For example, if the desktop assessment
indicates that the risk of illicit discharges is
low in the community, program managers
may want to shift resources to other
minimum management measures and
integrate them into a broader watershed
assessment and restoration effort. For
example, IDDE programs may emphasize
storm water education, public involvement
and hotline setup. By contrast, if the desktop
assessment reveals significant potential for
severe discharges, program managers will
need to allocate significant program resources
to find and fix the discharge problems.

The recommended scale for desktop assess-
ments is the subwatershed or sewer shed,
                 which typically range from two to 10 square
                 miles in area. These small planning units are
                 easily delineated on maps or a GIS system.
                 Next, mapping, monitoring and other data
                 are analyzed to identify subwatersheds with
                 the greatest potential to contribute illicit
                 discharges. The sophistication of the analysis
                 varies depending on the data available, but
                 can encompass up to 10 different screening
                 factors. The desktop assessment consists of
                 five basic steps:

                 Limited mapping or data should not hinder
                 a desktop assessment. Most communities
                 will have some gaps, but should make the
                 most  out of what they have. The desktop
                 assessment is an office exercise to locate  the
                 most  promising subwatersheds to find illicit
                 discharge; subsequent outfall screening is
                 needed to discover the problem outfalls in
                 the field.

                 Step 1: Delineate subwatersheds

                 Step 2: Compile mapping layers and
                        subwatershed data

                 Step 3: Compute discharge screening factors

                 Step 4: Screen for illicit discharge potential
                        at the subwatershed and community

                 Step 5: Generate maps to support field


                 Since hundreds of outfalls and many
                 stream miles exist in most communities,
                 the MS4 should be divided into smaller,
                 more manageable planning units known
                 as subwatersheds. If the community
                 already does watershed planning, these
                 subwatersheds may already be delineated,
                 and should be used for subsequent
                 characterization and screening. Working
                 at the subwatershed scale is usually the
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                                  Chapter 5: Desktop Assessment of Illicit Discharge Potential
most efficient way to conduct both desktop
assessments and field surveys.

In small, heterogeneous or densely
developed MS4s, conducting the assessment
on a smaller scale may be more effective. In
this case, sewersheds or catchments that are
less than one square mile in area and have
a common outfall or discharge point should
be delineated. This finer level delineation
allows for a refined characterization that
can pinpoint probable sources of illicit
discharges, but can obviously consume a lot
of time. It should be noted that sewersheds
do not always follow topographic
delineations and therefore can provide a
more accurate picture of the contributing
areas to a particular outfall.

If subwatersheds are not yet defined, hydro-
logic,  infrastructure and topographic map
layers are needed to delineate the boundaries.
Guidance on the techniques for accurately
delineating subwatershed boundaries can be
found at (click
"Slideshows," then scroll down to "Delineat-
ing Subwatershed Boundaries"). The use of
digital elevation models (DEMs) and GIS
can also make subwatershed delineation
an easier and faster, automated process.

Some subwatersheds extend beyond the
political boundaries of a community. Where
possible, it is recommended that the entire
subwatershed be delineated and assessed in
conjunction with neighboring municipalities.
This helps to ensure that all potential
sources of illicit discharges are identified
in the subwatershed, regardless of the
community from which they originate.

Step 2: Compile Mapping Layers
and Subwatershed Data

Once  subwatersheds (or catchments) are
delineated, a community can begin to
acquire and compile existing data for each
drainage area, preferably with a Geographic
Information System (GIS). A GIS allows
the user to analyze and manipulate spatial
data, rapidly update data and create new
data layers, associate data tables with
each map layer, and create paper maps to
display subwatershed information. A GIS
can greatly speed up data compilation and
provides greater accuracy in mapping specific
locations. The mapping information facilitates
the interpretation and understanding of the
discharge screening factors  (Step 3).

If a community does not currently have  a
GIS, developing a system from scratch may
seem daunting, however, most GIS software
can be installed on basic PCs, and free GIS
data layers are often available online. The
basic elements of a GIS program include
a PC, Global Positioning System (GPS)
units, a plotter, a digitizer, GIS software,
data and staff training. As with many
technologies, both low-end and high-end
versions are available, as are many add-ons,
extensions and tools. While a GIS is not
necessary for the IDDE desktop assessment,
it does make the process more efficient
and accurate, which can save money in the
long run. Moreover, other agencies within
a community usually need or use GIS and
may be willing to share hardware, software,
support and development costs7.

Acquiring data for each  subwatershed is the
next step in the desktop assessment process.

The extent and quality of the data available
for mapping directly influence subsequent
analyses and field investigations. A list of
recommended data layers to acquire for the
desktop assessment is provided in Table 13.
7 If a community plans to defer using GIS, all databases it
develops should have location information suitable for later
use with GIS (i.e., using suitable georeferencing technology
such as GPS).
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Chapter 5: Desktop Assessment of Illicit Discharge Potential
Some mapping data may exist in GIS format,
whereas others are only available in digital or
hardcopy formats that need to be converted
to GIS. Digital data with a geo-spatial
reference such as latitude and longitude,
parcel ID numbers  or addresses can be
directly entered into a GIS, if an existing
road or parcel GIS layer can be associated
to it. Hardcopy maps can also be digitized
to create new GIS data layers. This can be a
labor-intensive process, but will only need
to be done once and can be easily updated.
If GIS is not an option, hardcopy maps and
data can be analyzed, with an emphasis on
tax maps, topographic maps, historic aerial
surveys, and storm drain and outfall maps.

Most data layers can be obtained from local
sources, such as the city planning office,
                  emergency response agency, or public works
                  department. If a subwatershed extends
                  beyond the boundaries of your community,
                  you may need to acquire data from another
                  local government. Some data layers may be
                  available from state and federal agencies and
                  commercial vendors. EPA and most state
                  environmental agencies maintain databases
                  of industrial NPDES, CERCLA, RCRA and
                  other sites that handle or discharge pollutants
                  or hazardous materials. These searchable
                  permit databases are often available as
                  GIS layers (see Appendix A).  Commercial
                  vendors are good sources for low-altitude
                  aerial photos of your community. Aerial
                  photos can be expensive but are often the
                  best way to get a recent high-resolution
                  'snapshot' of subwatershed conditions.
Table 13: Useful Data for the Desktop Assessment

Aerial photos or orthophotos
Subwatershed or catchment boundaries
Hydrology including piped streams
Land use or zoning
NPDES storm water permittees
Sewer system, 1" = 200' scale or better
Standard Industrial Classification codes for all industries
Storm drain system, 1" = 200' scale or better
Street map or equivalent CIS layers
Topography (5 foot contours or better)
Age of development
As-builts or construction drawings
Condition of infrastructure
Field inspection records
Depth to water table and groundwater quality
Historical industrial uses or landfills
Known locations of illicit discharges (current and past)
Outfall and stream monitoring data
Parcel boundaries
Pollution complaints
Pre-development hydrology
Sanitary sewer Infiltration and Inflow (I/I) surveys
Septic tank locations or area served by septic systems
Sewer system evaluation surveys
Likely Format
Digital map
Digital or hardcopy map
Digital or hardcopy map
Digital or hardcopy map
Digital data or map
Digital or hardcopy map
Digital or hardcopy map
Digital or hardcopy data
Digital or hardcopy map
Digital or hardcopy map
Digital or hardcopy map
Narrative data
Hardcopy map
Narrative data
Hardcopy or digital data
Digital data or maps
Narrative data or hardcopy map
Narrative data or digital map
Digital data
Digital or hardcopy map
Narrative data
Narrative data or hardcopy map
Hardcopy or digital data
Hardcopy or digital map
Hardcopy or digital data
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                                  Chapter 5: Desktop Assessment of Illicit Discharge Potential
Alternatively, TerraServer (http://terraserver. is a free
mapping resource that most communities
can use to get good quality aerial and other
coverages (Figure 8 is an example). Higher
quality photos may be desirable as more
detailed investigations are pursued.

As GIS technology has become more afford-
able and easier to use, Phase II communities
should harness their capabilities to develop
the  storm sewer system maps required by
NPDES permits. GIS can become a powerful
tool to track and manage the entire IDDE
program, and demonstrate compliance in
annual reports. In addition to being a power-
ful tool for analysis, GIS is also a great tool
for communicating with the public. The
images that can be created with GIS can
summarize tables of data in a way that the
public appreciates. If the recommended
data layers are not available, a community
may want to devote program resources to
create or obtain them.  Once data layers have
been collected and digitized, they can be
entered into the GIS to create a map of each
subwatershed (Figure 8). Make sure all data
layers are in the same coordinate system,
and perform any conversions needed. Clip
data layers to subwatersheds to enable
calculation of factors such as land use,
area, and outfall density. Summary data on
subwatershed water quality and statistics
on the age and condition of infrastructure
should be entered into a database created for
analysis in the next step.

Step 3: Compute Discharge
Screening Factors

The third step  of the desktop assessment
defines and computes discharge factors to
screen  subwatersheds based on their illicit
discharge potential (IDP). As many as 10
different discharge screening factors can be
derived during the screening process, but
not all may apply to every community. The
potential screening factors are described
in Table 14, along with how they are
measured or defined. Keep in mind that
                     Figure 8: GIS Layers of Outfalls in a Subwatershed
            Markings illustrate Tuscaloosa, AL outfalls and drainage areas surveyed as part of this project.
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Chapter 5: Desktop Assessment of Illicit Discharge Potential
Table 14: Defining Discharge Screening Factors in a Community
Discharge Screening
1. Past Discharge
Complaints and
2. Poor Dry Weather
Water Quality
3. Density of Generating
Sites or Industrial
NPDES Storm Water
4. Storm Water Outfall
5. Age of Subwatershed
6. Sewer Conversion
7. Historic Combined
Sewer Systems
8. Presence of Older
Industrial Operations
9. Aging or Failing Sewer
10. Density of Aging
Septic Systems
Defining and Deriving the Factor
Frequency of past discharge complaints, hotline reports, and spill responses
per subwatershed. Any subwatershed with a history of discharge complaints
should automatically be designated as having high I DP.
Frequency that individual samples of dry weather water quality exceed
benchmark values for bacteria, nutrients, conductivity or other predetermined
indicators. High risk if two or more exceedances are found in any given year.
Density of more than 10 generating sites or five industrial NPDES storm water
sites per square mile indicates high I DP. Density determined by screening
business or permit databases (Appendix A).
Density of mapped storm water outfalls in the subwatershed, expressed as the
average number per stream or channel mile. A density of more than 20 outfalls
per stream mile indicates high IDP.
Defined as the average age of the majority of development in a subwatershed.
High IDP is often indicated for developments older than 50 years. Determined
from tax maps and parcel data, or from other known information about
Subwatersheds that had septic systems but have been connected to the
sanitary sewer system in the last 30 years have high IDP.
Subwatersheds that were once served by combined sewer system but were
subsequently separated have a high IDP.
Subwatersheds with more than 5% of its area in industrial sites that are more
than 40 years old are considered to have high IDP. Determined from historic
zoning, tax maps, and "old-timers."
Defined as the age and condition of the subwatershed sewer network. High
IDP is indicated when the sewer age exceeds design life of its construction
materials (e.g., 50 years) or when clusters of pipe breaks, spills, overflows or I/I
are reported by sewer authorities.
Subwatersheds with a density of more than 100 older drain fields per square
mile are considered to have high IDP. Determined from analysis of lot size
outside of sewer service boundaries.
these screening factors are a guide and
not a guarantee. Each screening factor is
described in detail in the following section.

 7. Past Discharge Complaints and
Many communities already have some
handle on where illicit discharges have
occurred in the past, based on past
complaints, reports and interviews with
spill responders and public works repair
crews. Pollution complaints made to the
                 local environmental or health department
                 are also worth analyzing. Each of these
                 historical sources should be analyzed to
                 determine if any patterns or clusters where
                 illicit discharges have historically occurred
                 can be found. Ideally, the number of past
                 discharge complaints should be expressed
                 on a subwatershed basis. Even if there is not
                 enough data to quantify past discharges, it
                 may be helpful to get a qualitative opinion
                 from public works crews.
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                                  Chapter 5: Desktop Assessment of Illicit Discharge Potential
2. Poor Dry Weather Wafer Quality
If dry weather water quality monitoring data
have been collected for local streams, it can
be an extremely useful resource to screen
subwatersheds for IDP. In particular, look
for extreme concentrations of enterococci
or E. coll, or high ammonia-nitrogen or
conductivity. Remember to edit out any
samples that were collected during or
shortly after storm events, as they reflect
the washoff of pollutants during storm
water runoff. In general, most communities
have more subwatersheds than baseflow
monitoring stations, so complete coverage is
usually lacking. The following benchmarks
are recommended to flag streams with high
IDP, based on individual samples of dry
weather water quality that exceed:

ป  Fecal coliform or E. coli standards (e.g.,
   typically 1,000 to 5,000 MPN/100 ml)

ป  Ammonia-nitrogen levels of 0.30 mg/1

•  Total phosphorus of 0.40 mg/1

•  Conductivity levels that exceed the 90th
   percentile value for the pooled dataset

Subwatersheds can be classified as having
a moderate risk if stream water quality
values exceed half the benchmark value.
An alternative approach is to statistically
analyze long-term dry weather water quality
monitoring dataset to define breakpoints
(e.g., 50th, 75th, and 90thpercentiles).

3, Density of Generating Sites or
   Industrial NPDES Storm Water
The density of potential generating sites in
a subwatershed can be a good screening
factor, if land use and business databases
are available. The basic database screening
method used to locate commercial,
industrial, institutional, municipal and
transport-related generating sites is described
in Chapter 1 and Appendix A. From the
standpoint of discharge screening, the key
variable to derive is the density of potential
generating sites (e.g., sites/square mile).
As a rule of thumb, more than 10 potential
generating sites per square mile would
indicate a high IDP, while subwatersheds
with three to 10 generating sites per square
mile might suggest a medium I DP.

Alternatively, communities may want to
develop screening factors based on the
density of industrial storm water permits
in place within the subwatershed. State
or federal regulatory agencies often have
geospatial databases of industrial NPDES
discharges that can be rapidly screened.
Pretreatment programs are another valuable
source of information on industrial and non-
domestic discharges to the sanitary system.

4, Storm Water Outfall Density
The density of outfalls in a subwatershed
is an effective discharge screening factor,
and is expressed in terms of the number of
outfalls per stream mile. Outfall density
can be determined by analyzing storm
drain maps, if they exist (although they
often miss the smaller diameter outfalls
that can also produce discharges). In
general, subwatersheds that have more than
20 mapped outfalls per stream mile may
indicate a higher risk for IDP. Alternatively,
the breakpoints for outfall density can be
statistically analyzed based on the frequency
across all subwatersheds.

5, Age of Subwatershed
The average age of development in a
subwatershed may predict the potential for
illicit discharge problems. For example,
a subwatershed where the average age of
development is more than 100 years was
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Chapter 5: Desktop Assessment of Illicit Discharge Potential
probably constructed before sewer service
was widely available, and many of the pipes
and connections may have changed over
the years as a result of modernization and
redevelopment. Presumably, the risk of
potential discharges would be higher in these
older subwatersheds. By contrast, a recently
developed subwatershed may have a lower
discharge risk due to improved construction
materials,  codes and inspections.
Therefore, high IDP may be indicated when
subwatershed development is more than
50 years old, with medium IDP for 20 to
50 year old development, and low IDP if
fewer than 20 years old. You should always
check with local building and plumbing
inspectors to confirm the building eras  used
in the screening analysis. The actual age of
development can be estimated by checking
tax maps and plats, or based on architecture,
or common knowledge of neighborhoods.

6, Sewer Conversion
Subwatersheds that were once served
by septic systems but were subsequently
connected often have a high IDP. These
subwatersheds are identified by reviewing
past sewer construction projects to
determine when and why sewer service was

7, Historic Combined Sewer Systems
 Subwatersheds that were once served
by combined sewer systems but were
subsequently separated often have a high
IDP. They can be identified by reviewing
past municipal separation projects.

8, Presence of Older Industrial
Older industrial areas tend to have a high
potential for illicit cross-connections for
several reasons. First, sanitary sewers may
not have been installed to handle wash
                 water, process water and other discharge
                 flows when the operation was originally
                 constructed. In the past, storm drains were
                 often used to handle non-sewage discharges
                 at older industrial facilities. In addition,
                 sanitary and storm drain lines built in
                 different eras are poorly mapped, which
                 increases the chance that someone gets the
                 plumbing wrong during an expansion or
                 change in operations at the facility. As a
                 result, older industries may inadvertently
                 discharge to floor drains or other storm
                 drain connections thinking they are
                 discharging pretreated water to the sanitary
                 sewer. Finally, older industries that produce
                 large volumes of process water may not have
                 enough sanitary sewer capacity to handle
                 the entire discharge stream, causing them to
                 improperly discharge excess water through
                 the storm drain system.

                 For these reasons, subwatersheds where
                 older industry is present should be regarded
                 as having a high IDP. For operational
                 purposes, older industry is defined as sites
                 that predate the Clean Water Act (e.g., 40
                 years old or more). They can be identified
                 from historic zoning and land use maps, old
                 parcel records or talking with old-timers.

                 9, Aging or Failing Sewer
                 Aging or failing sewer infrastructure often
                 signals potential illicit discharges, and can
                 be defined by the age and condition of the
                 subwatershed sewer network. High IDP is
                 indicated when the sewer age exceeds the
                 design life of its construction materials (e.g.,
                 50 years) or when clusters of pipe breaks,
                 spills, overflows or infiltration and inflow
                 (I&I) are reported by sewer authorities.
                 Older and aging sewer infrastructure
                 experience more leaks, cross-connections
                 and broken pipes that can contribute  sewage
                 to the storm drain system. The key factor
Illicit Discharge Detection and Elimination: A Guidance Manual

                                 Chapter 5: Desktop Assessment of Illicit Discharge Potential
to determine is the approximate age of the
sewer pipes and their construction materials,
which can be gleaned from sewer maps
I&I studies, or interviews with crews that
regularly repair broken or leaking sewer

10, Density of Aging Septic Systems
Subwatersheds located outside of the sewer
service area are presumably served by septic
systems. Septic systems more than 30 years
old are prone to failure, based on many site
factors (Swann, 2001). In general, a high
IDP is indicated if older septic tank density
exceeds 100 per square mile. Sewer envelope
boundaries or sewer network maps can be
helpful to identify subwatersheds that are
served by septic systems. Actual density
is determined by counting or estimating
the total number of septic households in
the subwatershed. Tank density should be
expressed as septic  system units per square
mile (average lot size can also be used as a
surrogate estimator).
Step 4: Screen for Illicit Discharge
Potential at the Subwatershed and
Community Level

The process for screening IDP at the
subwatershed level is fairly simple. The
first step is to select the group of screening
factors that apply most to your community,
and assign them a relative weight. Next,
points are assigned for each subwatershed
based on defined scoring criteria for each
screening factor. The total subwatershed
score for all of the screening factors is
then used to designate whether it has a
low, medium or high risk to produce illicit
discharges. Table 15 provides an example.
Based on this comparison, high-risk
subwatersheds are targeted for priority
field screening. It is important for program
managers to track and understand which
screening factors contributed to identifying
a watershed as "high-risk," as this may
affect the type of investigatory strategy that
is used for a particular watershed.
Table 15: Prioritizing Subwatersheds Using IDP Screening Factors

Subwatershed A
Subwatershed B
Subwatershed C
Subwatershed D
Subwatershed E
(total number
8 (2)*
3 (1)
13 (3)
1 (1)
5 (1)
Poor dry
water quality
(% of times
standards are
30% (2)*
15% (1)
60% (3)
25% (1)
15% (1)
of storm
(# of outfalls
per stream
14 (2)*
10 (2)
16 (2)
9 (1)
21 (3)
age of
40 (2)*
10 (1)
75 (3)
15 (2)
20 (1)
IDP score**
* The number in parentheses is the IDP "score" (with 3 having a high IDP) earned for that subwatershed and screening factor.
Basis for assigning scores (based on benchmarks) to assess IDP is as follows:
Past discharge complaints/reports: <5 = 1 : 5-10 = 2; >10 = 3
Dry weather water quality: <25% = 1 ; 25-50% = 2; >50% = 3
Storm water outfall density: <10 = 1; 10-20 = 2; >20 = 3
Average age of development: <25 = 1 ; 25- 50 = 2; >50 = 3
** Normalizing the raw IDP scores (by dividing the raw score by the number of screening factors assessed) will produce scores
that fall into the standard scale of 1 to 3 for low to high IDP, respectively.
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 5: Desktop Assessment of Illicit Discharge Potential
The example provided in Table 15 uses
four screening factors to assess five
subwatersheds in a community. Data for
each factor are compared against assigned
benchmarks, as  shown in the table. Each
subwatershed receives a specific score
for each individual screening factor.
These scores are then totalled for each
subwatershed, and the one with the highest
score is given top priority screening. In this
case, the screening priority would be given
to Subwatershed C, then A, followed by E.
Subwatersheds B and D, with the lowest
potential for illicit discharges, have the
lowest priority.

A similar screening process can be used to
evaluate the IDP for the community as a
whole. In this case, the entire population of
subwatersheds in the community is analyzed
to collectively determine the frequency of
the three risk areas: high, medium, and
low. Predefined  criteria for classifying the
community's IDP should be developed.
                 Table 16 and Figure 9 present an example
                 system for classifying IDP as minimal,
                 clustered or severe, based on the proportion
                 of subwatersheds in each risk category. The
                 community-wide assessment helps program
                 managers define their initial IDDE program
                 goals and implementation strategies, and
                 target priority subwatersheds for field

                 Step 5:  Generate Maps to Support
                 Field Investigations

                 The last step in this program component
                 involves generating the maps that field
                 crews need to screen outfalls in priority
                 subwatersheds.  More detail on mapping
                 requirements is provided in Chapter
                 11. The basic idea is to create relatively
                 simple maps that show streams, channels,
                 streets, landmarks, property boundaries
                 and known outfall locations.  The idea is to
                 provide enough information so crews can
                 find their  way in the field without getting
                 lost, but otherwise keep them uncluttered.
                 Low altitude aerial photos are also a handy
                 resource when available.
Table 16: Community-wide Rating of Illicit Discharge Potential
Minimal (no known problems)
Clustered (isolated problems)
Severe (severe problems)
Majority of subwatersheds have a Low IDP risk, with the
having Medium IDP risk
More than 20% of subwatersheds with a Medium or High
are in close proximity to each other
More than 50% of subwatersheds with a Medium or High
more than 20% of subwatersheds with a High IDP risk
IDP risk that
IDP risk or
Illicit Discharge Detection and Elimination: A Guidance Manual

                                Chapter 5: Desktop Assessment of Illicit Discharge Potential
                                                                   Low I DP risk
                                                                   Medium IDP risk
                                                                   High IDP risk
              Figure 9: Communities with Minimal (a), Clustered (b), and Severe
                              (c) Illicit Discharge Problems
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 5: Desktop Assessment of Illicit Discharge Potential
56                          Illicit Discharge Detection and Elimination: A Guidance Manual

                       Chapter 6: Developing Program Goals and Implementation Strategies
                         Chapter 6: Developing Program
                     Goals and Implementation Strategies
Purpose: This program component defines
the goals and performance milestones
to measure progress in IDDE program
implementation during the first permit cycle,
and selects the most appropriate and cost-
effective strategies to find, fix and prevent
illicit discharges. The goals and strategies
ensure that scarce local resources are
allocated to address the most severe illicit
discharge problems that cause the greatest
water quality problems in the community.

Method: The basic method is to analyze
the results of the IDDE  audit, desktop
analysis and local water quality conditions
to develop realistic, achievable and
measurable goals for the program. The
public and other stakeholders should be
involved in the goal setting process. Once
goals are selected, program managers need
to select the appropriate implementation
strategies and develop a timeline to make
them happen. Both goals and strategies
should closely align with the type and
severity of water quality problems and
local watershed management priorities. The
probable contribution of illicit discharges
to specific water quality problems should
be estimated or modeled to determine the
degree to which control efforts can meet
local TMDLs, bacteria standards for water
contact recreation, or other local water
quality concerns.
Desired Product or Outcome(s): Agreement
on program goals, measurable indicators and
implementation strategies that address four
key areas:

•  Overall program administration

•  Outfall assessment

•  Finding and fixing illicit discharges

•  Prevention of illicit discharges

Budget and/or Staff"Resources Required:
Staff effort to draft the goals and strategies,
conduct needed meetings, respond to
comments and finalize ranges from two to
six weeks. Goals and strategies should be
revisited and updated annually and at the
end of each permit cycle. Staff and budget
costs are not anticipated to be high unless a
fundamental shift in program goals occurs.

Integration with Other Programs: Goal
setting is always a good opportunity for
public involvement, storm water education
and watershed outreach. Effective
implementation strategies often  involve cost
sharing with other departments and even
other communities for monitoring equipment
and lab facilities, hotlines, and education
(e.g., public health/septic system programs).
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 6: Developing Program Goals and Implementation Strategies
6.1                of

Communities can define program goals and
implementation strategies once they understand
the extent of their illicit discharge problem and
how it influences local water quality. Initial
program goals should be realistic and provide
specific completion milestones to measure
program compliance. Measurable goals enable
a community to track and evaluate permit
compliance over time,  and to reassess and
modify the program over time. The most basic
measure of program effectiveness is to assess
whether program goals are being met. So, if a
program goal is to walk all stream miles and
inventory all outfalls in the MS4 within the
first permit cycle, this becomes a benchmark
that determines program effectiveness. If a
community finds that they only managed to
walk and inventory 80% of stream miles, the
program may need to be modified so that a
full screening sweep is completed in a permit
cycle, or they may need to adjust the goal or


The NPDES Phase II MS4 permit regulations
grant communities considerable flexibility to
develop program goals, as long as they are
defined in a measurable way to gauge permit
compliance and program effectiveness. EPA
(2000e) states that goals "should reflect the
needs and characteristics of the operator and
the area served by its small MS4. Furthermore,
they should be chosen using an integrated
approach that fully addresses the requirements
and intent of the minimum control measure."
               With this in mind, a series of representative
               goals that might be set for an IDDE program
               are presented in Table 17, along with
               proposed milestones. Four broad types of goals
               should be developed for every program:

               1.   Overall program administration

               2.   Outfall assessment

               3.   Preventing illicit discharges

               4.   Finding and fixing illicit discharge

               The assumed timeframe is based on a five-
               year permit cycle. Some of the program goals
               outlined in Table 17 are considered essential
               while others are optional or recommended.
               Communities should feel free to adapt these
               suggested program goals to reflect their unique
               conditions and capabilities, or create new
               ones. The key point is that program goals
               should always have a timeframe to serve as
               a benchmark for whether the goal has been

               Implementation strategies are designed to
               achieve program goals, and vary depending
               on the types and severity of illicit discharge
               problems in the community. These are outlined
               in more detail in the next section.
Illicit Discharge Detection and Elimination: A Guidance Manual

                      Chapter 6: Developing Program Goals and Implementation Strategies
Table 17: Measurable Goals for an IDDE Program
Goals related to overall program administration
Audit existing capabilities and identify needs
Designate one program head and identify key support staff
Develop a complete list of ongoing activities related to
Coordinate and communicate with other affected agencies
Develop a projected 5-year budget
Secure funding to match 5-year goals
Draft and promulgate new or modified ordinance
Establish a tracking and reporting system
At program start up and
continuously and regularly after
Goals related to outfall assessment
Define and characterize drainage areas or sewer sheds
Walk all stream miles
Develop a digital (e.g., CIS) map of all outfalls, land use,
and other relevant infrastructure
Secure analytical laboratory services either internally or by
arrangement with a private laboratory
Sample and trace the source of a percentage of flowing
outfalls each year of permit cycle
Conduct regular in-stream assessments
Conduct investigations at a percentage of non-flowing
outfalls with poor in-stream water quality to look for
intermittent flows
Integrate all collected stream data and citizen complaints
into the CIS system
Begin in Year 1 and complete first
screening by end of permit cycle.
Repeat once per permit cycle
Year 1 and continuously and
regularly after that
Initiate in conjunction with field
Initiate during first permit cycle
and expand and enhance where
problems are observed
Initiate during first year and
expand and enhance with time
Goals related to preventing illicit discharges
Distribute educational materials to citizens and industries
Conduct storm drain stenciling
Hold hazardous waste collection days at least annually
Conduct upland subwatershed site reconnaissance
surveys to better characterize generating site potential
Initiate during first year and
expand and enhance with time
Initiate during first permit cycle
and expand and enhance where
problems are observed
Goals related to finding and fixing illicit discharges
Develop a spill response plan and coordinate emergency
response with other agencies
Remove all obvious illicit discharges
Ongoing in conjunction with field
screening and in response to
hotline reports
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 6: Developing Program Goals and Implementation Strategies
Table 17: Measurable Goals for an IDDE Program
Train staff on techniques to find the source of an illicit
Repair a fraction of the illicit discharges identified through
field screening or citizen complaints
Establish a hotline for public to call in and report incidents
(consider establishing performance standards, such as
guaranteed response time)
Inspect and dye-test all industrial facilities
Develop a system to track results of on-site inspections
Establish an Adopt-a-Stream program
Establish pre-approved list of plumbers and contractors to
make corrections
Initiate during first year and
expand and enhance with time
Initiate during first permit cycle
and expand and enhance where
problems are observed
Initiate during first year and
expand and enhance with time
Initiate during first permit cycle
and expand and enhance where
problems are observed
Initiate during first year and
expand and enhance with time
Initiate during first permit cycle
and expand and enhance where
problems are observed
Initiate during first year and
expand and enhance with time
Key: • Essential O Optional but Recommended
Ultimately, IDDE program goals should be
linked to water quality goals. Some common
examples of water quality goals include:

•  Keep raw or poorly-treated sewage out
   of streams

•  Reduce pollutant loads during dry
   weather to help meet the TMDL for a
   water body

•  Meet bacteria water quality standards
   for contact recreation during dry weather

•  Reduce toxicant and other pollutant
   discharges to a stream to restore the
   abundance and diversity of aquatic
   insects or fish

A well-designed IDDE program may
not guarantee that water quality goals
will be always be achieved. Indeed, if
program managers can document that illicit
discharges do not contribute to poor water
                 quality, they may want to shift resources
                 to other pollution sources or practices that
                 do. Burton and Pitt (2002) offer a complete
                 discussion on designing and conducting a
                 receiving water investigation.

                 6.3    Crafting Implementation

                 In order to meet program goals, managers
                 must devise cost-effective implementation
                 strategies that are most appropriate for the
                 types of illicit discharge problems they
                 actually have. The community-wide illicit
                 discharge potential (IDP) developed during
                 the desktop analysis can be quite helpful in
                 choosing implementation strategies. Table
                 18 presents implementation strategies that
                 are geared to the findings of the community-
                 wide IDP.  As the community acquires more
                 program experience, they can refine the
                 strategies to better address program goals or
                 unique watershed conditions (Table 19).
Illicit Discharge Detection and Elimination: A Guidance Manual

                          Chapter 6: Developing Program Goals and Implementation Strategies
Perhaps the most important implementation
strategy is targeting—screening, education
and enforcement efforts should always be
focused on subwatersheds, catchments
or generating sites with the greatest IDP.
Adaptability after program startup is also
                           an important strategy. Strategies developed
                           from the desktop analysis should be
                           constantly adjusted to reflect knowledge
                           gained from field screening, hotline reports
                           and other monitoring information.
              Table 18: Linking Implementation Strategies to Community-wide IDP
        Type                            Examples of Implementation Strategy
     Minimal IDP
Conduct field screening of outfalls in the context of broader watershed
assessment and restoration initiatives using the Unified Stream Assessment
(CWP, 2004) or a comparable physical stream assessment approach that has
broader focus and benefits.
Integrate IDDE program efforts into more comprehensive watershed assessment
and restoration efforts where multiple objectives are being pursued (e.g., storm
water education).
Target and coordinate with existing small watershed organizations as partners to
accomplish inventory and data collection efforts.
Establish hotline to report suspicious discharges.
    Clustered IDP
Conduct limited sampling in the suspect areas. The most cost-effective approach
will likely involve using outside laboratory services to avoid capital costs for
special equipment (in some cases a municipal laboratory may be available for
limited cost).
Select a small set of indicator parameters using the nature of historic problems
and land use as a guide.
Target education program in problem areas.
Look for partnerships with local watershed groups to regularly monitor problem
Establish a hotline to report suspicious discharges.
     Severe IDP
Establish a hotline to report suspicious discharges.
Conduct and repeat screening in all subwatersheds
Plan for more rigorous sampling approach to make establishment of internal
laboratory set up more cost effective (i.e., plan for equipment expenditures
for sample collection and analysis). Considerations include: expanding set of
parameters to use as indicators, adopting a strategy for targeting intermittent
discharges, and establishing in-stream stations to supplement screening effort.
Develop a community-specific chemical "fingerprint" of various flow sources to
facilitate differentiation between likely flow sources.
Develop community-wide educational messages aimed at increasing public
awareness and targeted education programs tailored to problem areas.
Look for partnerships with local watershed groups to be regular monitors of
problem areas through an adopt-a-stream approach.
Emphasize cross-training of municipal employees to develop a broader reach
of program efforts and lead by example by ensuring municipal facilities are not
contributing to illicit discharge problem.
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 6: Developing Program Goals and Implementation Strategies
         Table 19: Customizing Strategies for Unique Subwatershed Screening Factors
  Initial Problem
Screening Factor (from Table 14)
  Example Implementation Strategies
   Aging Sewer
  Complaints of sewage
  Poor dry weather quality
  High outfall density
  Septic to sewer conversion
  Historic combined system
  Aging sewers
Institute a point of sale inspection and
verification process.
Select a small set of indicator parameters that
focuses on sewage connections.
Develop cost share program to assist property
owners with connection correction.
   Aging Septic
  Aging septic systems
Develop targeted education program for septic
system maintenance and institute a point of
sale inspection and verification process.
Develop cost share capabilities to assist
property owners with upgrade of system.
 Discharges from
 Generating Sites
• Density of generating sites
• Older industry
• Past complaints and reports
Link IDDE program to existing industrial
NPDES discharge permits, and inspect storm
water management pollution prevention plans.
Develop targeted training and technical
assistance programs tailored to specific
generating sites.
Aggressively enforce fines and other
measures on chronic violators.
     High Spill
   or Dumping
  Past complaints and reports
Establish a hotline and develop community-
wide educational messages aimed at
increasing public awareness.
Look for partnerships with local watershed
groups to regularly monitor or adopt problem
Increase number and frequency of used oil
and hazardous waste recycling stations.
Post signs, with hotline reporting number at
dumping sites.
             Illicit Discharge Detection and Elimination: A Guidance Manual

                               Chapter 7: Searching for Illicit Discharge Problems in the Field
                            Chapter 7: Searching for Illicit
                           Discharge Problems in the  Field
Purpose: This program component
consists of detective work, and involves
rapid field screening of outfalls in priority
subwatersheds followed by indicator
monitoring at suspect outfalls to characterize
flow types and trace sources.

Method(s): The primary field screening tool
is the Outfall Reconnaissance Inventory
(ORI), which is used to find illicit discharge
problems and develop a systematic outfall
inventory and map of the MS4. The  ORI is
frequently supplemented with more  intensive
indicator monitoring methods to test suspect
outfalls. A wide range of monitoring
methods can be used; this chapter describes
a framework for choosing the safest, most
accurate and repeatable methods for a

Desired Product or Outcome(s): The search
for illicit discharge problems yields  several
important management products, including:

•  An updated map of the locations of all
   outfalls within the MS4

•  Incorporation of ORI data into the
   outfall inventory/tracking system

•  Design and implementation of an
   indicator monitoring strategy to  test
   suspect outfalls

•  Creation of a local chemical
   "fingerprint" library of pollutant
   concentrations for various discharge flow

•  Data reports that evaluate the
   significance and distribution of illicit
   discharge problems in the community
Budget and/or Staff Resources Required:
Field screening and indicator monitoring
can consume substantial staff and budget
resources. Monitoring costs are closely
related to the number of outfalls screened
and the complexity of illicit discharge
problems discovered. An MS4 that screens
10 stream miles and analyzes 80 indicator
samples each year can expect to spend about
$15,000 to $35,000. Consequently, choosing
which indicator(s) to use in a community
(and when and where to use them) ranks as
one of the most important budget decisions
for any project manager.

Integration with Other Programs: Program
managers should explore two strategies
to integrate field screening and indicator
monitoring with other programs to achieve
cost savings. The first strategy links outfall
screening to broader stream corridor
assessments that support local watershed
restoration efforts. Often, watershed
organizations and "stream waders" can
be enlisted and trained to conduct outfall
screening. The second strategy is to find a
local agency partner to conduct laboratory
analysis (such as a drinking water or
wastewater treatment plant).
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 7: Searching for Illicit Discharge Problems in the Field
7.1    Overview of Searching for
Illicit Discharge Problems in the

This chapter provides basic information
about the field and laboratory strategies
needed to detect illicit discharges, beginning
with a field screening technique designed to
gather basic information and identify highly
suspect outfalls or obvious discharges. Next,
it provides a basic framework for using the
data from this screening to address obvious
discharges, develop a chemical monitoring
program, and make future program
decisions. Finally, it summarizes the basic
options for conducting an ongoing chemical
monitoring program. The approaches
outlined here are only summarized briefly,
and primarily in the context of overall
program management. Much more detailed
and "hands-on" information is provided in
Chapters 11 and 12 that provide specific
methods and technical guidance for field
crew and laboratory staff.

7.2   The Outfall Reconnaissance
Inventory (ORI)

The field screening technique recommended
for an IDDE  program is the Outfall
Reconnaissance Inventory or ORI. The
ORI is a stream walk designed to inventory
and measure storm drain outfalls, and find
and correct continuous and intermittent
discharges without in-depth laboratory
analysis (Figure 10). The ORI should be
completed for every stream mile or open
channel within the community during the
first permit cycle, starting with priority
subwatersheds  identified in the desktop
analysis. Outfall screening requires
relatively little  expertise, and can be
incorporated into other stream assessments
such as the Unified Stream Assessment
(Kitchell and Schueler, 2004).
                 The ORI can discover obvious discharges
                 that are indicated by flowing outfalls with
                 very high turbidity, strong odors and colors,
                 or an "off the chart" value on a simple field
                 test strip. When obvious discharges are
                 found, field crews should immediately track
                 down and remove the source (see Chapters 8
                 and 13). In other instances, ORI crews may
                 encounter a transitory discharge, such as a
                 liquid or oil spill that should be immediately
                 referred to the appropriate agency for
                 cleanup (Figure 11).
                          Figure 10: Measuring an
                          outfall as part of the ORI
                       Figure 11: Some discharges are
                            immediately obvious
Illicit Discharge Detection and Elimination: A Guidance Manual

                                  Chapter 7: Searching for Illicit Discharge Problems in the Field
The ORI is not meant to be a "one size
fits all" method, and should be adapted to
suit the unique needs of each community.
Program managers should also modify the
ORI over time to reflect field observations,
crew experience, new or modified
indicators, and any other innovations that
make fieldwork easier or faster. Table 20
summarizes the four basic steps to conduct
an ORI, and more detail on ORI protocols is
provided in Chapter 11.
                       7.3    Interpreting ORI Data

                       Once the first few ORI surveys are
                       conducted, data can be analyzed to confirm
                       and update the desktop analysis originally
                       used for targeting subwatersheds. The ORI
                       data analysis follows four basic steps, which
                       are described in Table 21. Ideally, ORI data
                       should be stored within a continuously-
                       updated geospatial tracking system.
                        Table 20: Field Screening for an IDDE Program
 Step 1. Acquire necessary
 mapping, equipment and
• Use basic street maps or detailed maps from initial assessment
• Minimal field equipment required; use a portable spectrophotometer if
• Two staff per crew with basic field training required; more specialized staff
                              or training is optional
 Step 2. Determine when to
 conduct field screening
• During dry season and leaf off conditions
• After a dry period of at least 48 hours
                              Low groundwater levels
 Step 3. Identify where to
 conduct field screening
 (based on desktop
  Minimal: integrate field screening with broader watershed or stream
  Clustered: screen drainage areas ranking High and Medium first for illicit
  discharge potential
  Severe: screen all outfalls systematically
 Step 4. Conduct field
  Mark and photograph all outfalls
  Record outfall characteristics
  Simple monitoring at flowing outfalls
  Take flow sample at outfalls with likely problems
  Deal with major problems immediately
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 7: Searching for Illicit Discharge Problems in the Field
Table 21 : Field Data Analysis for an IDDE Program
Step 1. Compile data from the OKI
Step 2. Develop OKI designation for
Step 3. Characterize the extent of
illicit discharge problems
Step 4. Develop a monitoring
• Compile GPS data and photographs of outfall locations
• Enter OKI data into database
• Send any samples for lab analysis
• Use OKI data to designate outfalls as having obvious, suspect,
potential, or unlikely discharge potential
• Use data from initial assessment
• Use outfall designation data
• Update initial assessment of illicit discharge problems as
minimal, clustered, severe
• At a minimum, sample 1 0% of flowing outfalls per year
• Repeat field screening in second permit cycle
• Use various monitoring methods depending on outfall
designation and subwatershed characteristics
7.4    Design and Implementation
of an Indicator Monitoring

The next step is to design an indicator
monitoring program to test suspect or
problem outfalls to confirm whether
they are actually an illicit discharge, and
determine the type of flow. From a program
management standpoint, six core issues need
to be considered during the design of the
monitoring strategy, as shown in Table 22.

The indicator monitoring strategy should be
concentrated primarily on continuous and
intermittent discharges, and can be adapted
to isolate the specific flow type found in
a discharge. Figure 12 presents an overall
monitoring design framework that organizes
some of the key indicators and monitoring
techniques that may be needed. In general,
different indicators and monitoring methods
are used depending on whether flow is
present at an outfall or not. The details
of the discharge monitoring framework
are described in Chapter 12. The basic
framework should be adapted to reflect the
                 unique discharge problems and analytical
                 capabilities of individual communities.

                 Some of the recommended monitoring
                 strategies are discussed below. The preferred
                 method to test flowing outfalls is the flow
                 chart method that uses  a small  set of
                 indicator parameters to determine whether
                 a discharge is clean or dirty, and predicts
                 its or flow type (Pitt, 2004). The flow chart
                 method is particularly suited to distinguish
                 sewage and washwater flow types. Industrial
                 sites may require special testing, and the
                 benchmark concentrations method
                 includes several supplemental indicators to
                 distinguish industrial sources.
                        Table 22: Indicator Monitoring
                     Use OKI data to prioritize problem outfalls or
                     drainage areas
                     Select the type of indicators needed for your
                     discharge problems
                     Decide whether to use in-house or contract
                     lab analytical services
                     Consider the techniques to detect intermittent
                     Develop a chemical library of concentrations
                     for various flow types
                     Estimate staff time, and costs for equipment
                     and disposable supplies
Illicit Discharge Detection and Elimination: A Guidance Manual

                                Chapter 7: Searching for Illicit Discharge Problems in the Field

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„ Non - / ,
Flowing'V /
> 	 Intermittent .ฃ—
M o n i t o ri n Q 	 •&> O R I 	 &> F 1 o w i n Q C' 	

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ary Balance

                          Figure 12: IDDE Monitoring Framework
Non-flowing outfalls are more challenging
to diagnose. Intermittent flows can be
diagnosed using specialized monitoring
techniques such as:

ซ  Off hours mon itori ng

ซ  Caulk dams

•  Optical brightener monitoring traps

When intermittent discharges are captured
by these specialized techniques, samples
are normally diagnosed using the flow chart

Transitory discharges are extremely difficult
to detect with routine indicator monitoring,
and are frequently identified from hotline
reports. Transitory discharges are usually
diagnosed by inspection, although water
quality samples may be collected to support
enforcement measures.
As communities acquire more monitoring
data, they should consider creating a
chemical "fingerprint" library, which is
a database of the chemical make-up of the
many different flow types in the community.
Chemical libraries should include sewage,
septage, washwater, and common industrial
flows. Default values for the chemical
library can initially be established based on
existing research and literature values. Data
are then updated based on local monitoring
to develop more accurate decision points
in the flow chart or benchmark methods.
Clean water sources such as tap water,
groundwater, spring water, and irrigation
water are also important entries in the
chemical library. The chemical library
should also characterize the water quality
of known or unknown transitory discharges
sampled in the field. Over time, chemical
library data should help a community better
understand the potential pollutant loads
delivered to receiving waters from various
generating activities.
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 7: Searching for Illicit Discharge Problems in the Field
These library data can be used to support
more advanced strategies such as the
Chemical Mass Balance Model (CMBM)
method. This method, developed by the
University of Alabama as part of this project
(Karri, 2004), is particularly useful in
identifying flow types in blended discharges,
where groundwater or tap water is diluted
or commingled with sewage and other illicit
discharges. The CMBM requires substantial
upfront work to develop an accurate chemical
library for local flow types. Specifically, the
library requires 10-12 samples for each flow
type (for industrial flow types, samples can
be obtained in association with NPDES pre-
treatment programs). A user's guide for the
CMBM can be found in Appendix I.

          7.5             Lab

Program managers should take into account
and fully plan for all necessary field
and laboratory safety precautions. Most
communities already have well established
standard operating procedures they follow
when conducting field and lab work,
and these typically provide an excellent
starting point for I DDE programs. Chapters
11, 12, and 13 along with Appendices
F and G provide guidance on specific-
considerations associated with IDDE
programs. Of particular note is that program
managers may want to consider requiring/
recommending field crews be vaccinated
against Hepatitis B, particularly if the
crews will be accessing waters known to be
contaminated with illicit  sewage discharges.
Program managers should contact local
health department officials to explore this
issue in more detail prior to making a
                             Illicit Discharge Detection and Elimination: A Guidance Manual

                                  Chapter 8: Isolating and Fixing Individual Illicit Discharges

                         Chapter 8:  Isolating and Fixing
                            Individual Illicit Discharges
Purpose: This program component uses
a variety of tools to trace illicit discharge
problems back up the pipe to isolate the
specific source or improper connection that
generates the discharge. This often requires
improved local capacity to locate specific
discharges, make needed corrections and
maintain an enforcement program to ensure

Method(s): Five basic tools exist to isolate
and fix individual discharges, including:

•  Pollution reporting hotline

•  Drainage area investigations

•  Trunk investigations

•  On-site discharge investigations

•  Correction and enforcement

Desired Product or Outcome(s): Finding
and fixing illicit discharges is the core
goal of any IDDE program. The process of
finding and fixing discharges has several
desirable outcomes, such as:

•  Improved water quality

•  Increased homeowner and business
   awareness about pollution prevention

•  Maintenance of a tracking system to
   document repairs and identify repeat
Budget and/or Staff Resources Required:
Budget and staff resources needed to
find illicit discharges vary greatly. Some
discharge sources will be immediately
obvious, while others will require extensive
investigations up the  pipe until the source
can be sufficiently narrowed. Fixing
the problem once it is identified is more
predictable and can often involve qualified
contractors. Costs associated with repairs
can also be fully incurred by the offending
party or shared, depending on the nature and
extent of the illicit discharge.

Integration with Other Programs:
Two important aspects of this program
component can be integrated with other
NPDES minimum management measures
and storm water permitting. First, the
pollution hotline can  be an important
element of any local storm water education
initiative. Second, on-site illicit discharge
investigations should be closely coordinated
with  industrial NPDES storm water site
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 8: Isolating and Fixing Individual Illicit Discharges
8.1    Overview of Isolating
and Fixing Individual  Illicit

The ultimate goal of every IDDE program is
to find and fix illicit discharges, and a range
of tools are available to meet this objective.
The ensuing chapter discusses each of the
tools in more detail. The choice of which
tools are used depends on the nature of the
local storm drain system, and the type and
mode of entry of the discharges.

8.2    Isolating Illicit Discharges

Outfall screening and monitoring are
excellent for finding illicit discharge
problems, but they often cannot detect most
intermittent or transient flows, nor can they
always isolate the exact source, particularly
when the outfall has a large contributing
area and an extensive pipe network. This
section provides guidance on four tools to
find individual illicit discharges. The first
tool is a pollution complaint hotline, which
is particularly effective at finding obvious
illicit discharges, such as transitory flows
from generating sites and sewer overflows.
Citizens provide free surveillance around the
clock, and their reports should prompt rapid
investigations and enforcement. The other
three  investigative tools involve drainage
area, trunk, and on-site investigations.
                  Pollution Complaint Hotline

                  A complaint hotline is a dedicated phone
                  number or website where citizens can easily
                  report illicit discharge and pollution concerns.
                  The hotline should always be supported by
                  prompt investigations of each complaint by
                  trained inspectors,  usually within 24 hours.
                  Many Phase I communities have utilized
                  hotlines to track down intermittent and
                  transitory discharges, and regard them as
                  one of their most effective tools to isolate
                  illicit discharges (CWP, 2002). Some of the
                  benefits and challenges Phase I communities
                  have encountered in administering an IDDE
                  complaint hotline in summarized in Table 23.

                  Six basic steps are needed to establish and
                  maintain a successful IDDE complaint
                  hotline, which are outlined in Table 24. More
                  detailed guidance on  establishing a hotline is
                  provided in Appendix C, along with a sample
                  illicit discharge incident tracking form.

                  It is important to keep in mind that a
                  successful hotline requires considerable
                  advertising and outreach to keep the phone
                  number fresh in the public's mind. Also,
                  program managers should continuously
                  monitor response times, inspection outcomes,
                  and any enforcement  taken. All complaints
                  should be entered into the IDDE tracking
                  system so that complaints can be analyzed.

                  The cost to establish and maintain a hotline
                  varies, but savings can be realized if it can
                   Table 23: Benefits and Challenges of a Complaint Hotline
   Leads to early detection and correction of illicit discharges
   Encourages active public stewardship
   Can "piggyback" on other call response needs
   Identifies suspected facilities for further investigation and education
   Increases facilities' and municipalities' sense of accountability
   Increases likelihood of discovering intermittent discharges
                                Time and money to provide
                                24/7 service
                                Marketing the hotline number
                                Establishing inter- and intra-
                                departmental process
Illicit Discharge Detection and Elimination: A Guidance Manual

                                   Chapter 8: Isolating and Fixing Individual Illicit Discharges
Table 24:
1. Define the scope
2. Create a tracking and
reporting system
3. Train personnel
4. Advertise
5. Respond to
6. Track incidents
Steps to Creating and Maintaining Successful IDDE Hotline
Key Elements
Determine if a hotline is needed
Define the intent of the hotline
Define the extent of the hotline
Design reporting method
Design response method
The basics and importance of IDDE
The complaint hotline reporting, investigation and tracking process
How to provide good customer service
Expected responsibilities of each department/agency
Advertise hotline frequently through flyers, magnets, newspapers, displays, etc.
Publicize success stories
Provide friendly, knowledgeable customer service
Send an investigator to respond to complaints in a timely manner
Submit incident reports to the hotline database system
Identify recurring problems and suspected offenders
Measure program success
Comply with annual report requirements
be piggy-backed on an existing community
hotline or cost shared with other communities
in the region. Also, hotline costs are related to
the volume of calls and the staff effort needed
for follow-up investigations. A budgeting
framework for establish and maintaining a
hotline from scratch is provided in Table 25.

Illicit Discharge Investigations

Once an illicit discharge is detected at an
outfall  or stream, one of four types of illicit
discharge investigations is triggered to
track down the individual source. These
investigations are  often time consuming and
expensive, require special training and staff
expertise, and may result in legal action.
They include:
•  Storm drain network investigations

•  Drainage area investigations

•  On-site investigations

•  Septic system investigations

Each type of investigation handles a different
type of discharge problem and has its advan-
tages and disadvantages. More detail on these
investigations is provided in Chapter 13.

Storm drain network investigations
Storm drain or "trunk" investigations
narrow the  source of a discharge
Table 25: IDDE Complaint Hotline Costs
Define the scope
Create a tracking and reporting system
Train personnel
Respond to complaints
Track incidents
Initial Cost
Annual Costs
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 8: Isolating and Fixing individual Illicit Discharges
problem to a single segment of a storm
sewer. The investigation starts at the outfall,
and the field crew must decide how it will
explore the upstream pipe network. The
three options include:

•  Work progressively up the trunk from
   the outfall and test manholes along the

•  Split the trunk into equal segments and
   test manholes at strategic points of the
   storm drain system

•  Work progressively down the trunk (i.e.,
   from the headwaters of the storm drain
   network and move downstream)

The decision to move up, split, or move
down the trunk depends on the nature of the
drainage system and the surrounding land
use. The three options also require different
levels of advance preparation. Moving up
the trunk can begin immediately when an
illicit discharge is detected at an outfall,
and only a map of the storm drain system is
required. Splitting the trunk requires a little
more preparation to examine the storm drain
system and find the most strategic manholes
to sample. Moving down the trunk requires
even more advance preparation, since the
most upstream segments of the storm drain
network may be poorly understood.

Once crews choose one of these options,
they need to select the most appropriate
investigative methods to track down the
source. Common methods include:

•  Visual inspection at manholes

ซ  Sandbagging or damming the trunk

•  Dye testing

•  Smoke testing

•  Video testing
                  Drainage area investigations
                  Drainage area investigations are initially
                  conducted in the office, but quickly move
                  into the field. They involve a parcel by parcel
                  analysis of potential generating sites within
                  the drainage area of a problem outfall. They
                  are most appropriate when the drainage area
                  to the outfall is large or complex, and when
                  the flow type in the discharge appears to
                  be specific to a certain type of land use or
                  generating site. These investigations may
                  include the following techniques:

                  •   Land use investigations

                  ป   SIC code review  (see Appendix A)

                  ซ   Permit review

                  •   As-built review

                  *   Aerial photography analysis

                  ซ   Infrared aerial photography analysis

                  •   Property ownership certification

                  On-site investigations
                  Once the illicit discharge has been isolated
                  to a specific section of storm drain, an
                  on-site investigation  can be performed to
                  find the specific source of the discharge.
                  In some situations, such as subwatersheds
                  dominated by industrial land uses or many
                  generating sites, on-site investigations may
                  be immediately pursued.

                  On-site investigations are typically
                  performed by dye testing the plumbing
                  systems of households and buildings. Where
                  septic systems are prevalent, inspections of
                  tanks and drain fields may be needed.

                  On-site investigations are excellent
                  opportunities to combine 1DDE efforts with
                  industrial site inspections that target review
                  and verification of proper Storm Water
Illicit Discharge Detection and Elimination: A Guidance Manual

                                   Chapter 8: Isolating and Fixing Individual Illicit Discharges
Pollution Prevention Plans. Appendix A
provides a list of industrial activities
that typically require industrial NPDES
discharge permits.

Septic system investigations
Communities with areas of on-site sewage
disposal systems (i.e., septic systems)
need to consider alternative investigatory
methods to track illicit discharges that enter
streams as indirect discharges, through
surface breakouts of septic fields, or through
straight pipe discharges from bypassed
septic systems. Techniques can involve on-
site investigations or imagery analysis (e.g.,
infrared aerials).


Once the source of an illicit discharge has
been identified, steps should be taken to fix
or eliminate the discharge. Four questions
should be answered for each individual illicit
discharge to determine how to proceed; the
answers will usually vary depending on the
source of the discharge.

ซ  Who is responsible?

•  What methods will be used to repair?

•  How long will the repair take?

•  How will  removal be confirmed?
Financial responsibility for source removal
will typically fall on property owners, MS4
operators, or a combination of the two.
Methods for removing illicit discharges
usually involve a combination of education
and enforcement. A process for addressing
illicit discharges that focuses on identifying
the responsible party and enforcement
procedures is presented in Figure 13,
while Table 26 presents various options for
removing illicit discharges from various
sources. Additional information on common
removal actions and associated costs can be
found in Chapter 14.

Program managers should use judgment
in exercising the right mix of compliance
assistance and enforcement. The authority
and responsibility for correction and
enforcement should be clearly defined in
the local IDDE ordinance developed earlier
in the program. An escalating enforcement
approach is often warranted and is usually
a reasonable process to follow. Voluntary
compliance should be used for first-time,
minor offenders. Often, property owners
are not even aware of a problem, and are
willing to fix  it when educated. More serious
violations or continued non-compliance may
warrant a more aggressive, enforcement-
oriented approach.
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 8: Isolating and Fixing Individual Illicit Discharges
                                     Flow Chart for Corrective Action
                                   Contamination Source Identified
                              Determine Party Responsible for Making Repairs
                  Private Property Owner
                       Issue Work Order
                                                     Issue Notice of Violation (NOV)
                                                    Eliminate Contamination Source
                                                Confirm Elimination of Contamination Source
                                    |  Contamination Source Eliminated |   | Contamination Source Still Present
                                        Complete Documentation
                                                                     2nd Contamination Source Present
                                                                            Issue 2nd NOV
                                                                          Issue 2nd Work Order
                  Figure 13: Process for Removing or Correcting an Illicit Discharge
Table 26: Methods to Fix Illicit Discharges
Type of Discharge
Wash water
Liquid wastes
Break in right-of-way
Commercial or industrial direct connection
Residential direct connection
Infrequent discharge (e.g., RV dumping)
Straight pipes/septic
Commercial or industrial direct connection
Residential direct connection
Power wash/car wash (commercial)
Commercial wash down
Residential car wash or household maintenance-
related activities
Professional oil change/car maintenance
Heating oil/solvent dumping
Homeowner oil change and other liquid waste
disposal (e.g., paint)
Spill (trucking)
Other industrial wastes
Removal Action (s)
Repair by municipality
Enforcement; Incentive or aid
Enforcement; Spill response
Enforcement; Incentive or aid
Enforcement; Incentive or aid
Enforcement; Incentive or aid
Enforcement; Spill response
Enforcement; Spill response
Warning; Education; Fines
Spill response
Enforcement; Spill response
Illicit Discharge Detection and Elimination: A Guidance Manual

                                                    Chapter 9: Preventing Illicit Discharges
                              Chapter 9:  Preventing Illicit
Purpose: This program component identifies
key behaviors of neighborhoods, generating
sites, and municipal operations that produce
intermittent and transitory discharges. These
key "discharge behaviors" are then targeted
for improved pollution prevention practices
that can prevent or reduce the risk of dis-
charge. Communities then apply a wide
range of education and enforcement tools
to promote the desired pollution prevention

Method(s): The Unified Subwatershed and
Site Reconnaissance (USSR; Wright et al,
2004) and the desktop analysis of potential
generating sites (Chapter 5) are two methods
used to identify the major behaviors
that generate intermittent and transitory
discharges. These methods, used alone or
in combination, are extremely helpful to
identify the specific discharge behaviors
and generating sites that will be targeted for
education and enforcement efforts. A Source
Control Plan is then performed to select the
right pollution prevention message, choose
the appropriate combination of carrots and
sticks to change behaviors, and develop a
budget and delivery system to implement
the prevention program. Refer to Schueler
et al. (2004) for information on developing
a Source Control Plan and the many carrots
and sticks available to communities.

Desired Product or Outcome(s): The
desired outcome is a mix of local prevention
programs that target the most common
intermittent and transitory discharges in
the community. Program managers need
to develop targeted pollution prevention
programs for three sectors of the

•  Neighborhood Discharges. The pollution
   prevention practices related to discharge
   prevention in residential neighborhoods
   include storm drain stenciling, lawn
   care, septic system maintenance, vehicle
   fluid changing, car washing, household
   hazardous waste disposal and swimming
   pool draining.

•  Generating Sites. This group of pollution
   prevention practices can reduce spills
   and transitory discharges generated
   during common business operations.
   Practices include business outreach, spill
   prevention and response plans, employee
   training and site  inspections.

•  Municipal Housekeeping. This group
   of pollution prevention practices is
   performed during municipal operations,
   such as sewer and storm drain
   maintenance, plumbing code revision,
   and provision of household hazardous
   waste and used oil  collection services.

Budget and/or Staff Resources Required:
The budget and staff resources needed for
prevention programs can be considerable,
and should be coordinated with other storm
water education, public involvement and
municipal housekeeping initiatives required
under NPDES Phase IIMS4 permits. Special
emphasis should be placed on cross-training
staff, partnering with local watershed groups,
and pooling educational resources with other

Integration with Other Programs: Illicit
discharge prevention is linked to three of the
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 9: Preventing Illicit Discharges
six NPDES Phase II minimum management
measures, and should be closely integrated
with local watershed restoration efforts.

9.1                of

Intermittent and transitory discharges are
difficult to detect through outfall screening
or indicator monitoring. Indeed, the best
way to manage these discharges is to
promote pollution prevention practices in
the community that prevent them from
occurring. Effective IDDE programs develop
education and outreach materials targeted
toward neighborhoods, generating sites,
and municipal operations. The discharge
prevention message is  normally integrated
with other storm water education programs
required under MS4 NPDES Phase II
permits such as
•  Public education and outreach
*  Public participation/involvement
ป  Municipal pollution prevention/good

9.2                tO

The USSR and the desktop analysis of
potential generating sites both help identify
the major behaviors that generate intermittent
and transitory discharges. These assessment
methods are briefly described below:

Flie                                 Site

The USSR is a field survey that rapidly
evaluates potential pollution sources and
restoration potential in urban sub water sheds.
The survey quickly characterizes upland
areas in order to inventory problem
                  sites that may contribute pollutants and
                  identifies pollution source controls and other
                  restoration projects. For more information
                  on how to conduct the USSR, consult Wright
                  et al. (2004). The USSR has four major
                  assessment components, three of which
                  directly relate to illicit discharge prevention:

                  ป  Neighborhood Source Assessment
                     (NSA), which helps discover residential
                     pollution source areas and potential
                     restoration opportunities within the
                     many neighborhoods found in urban

                  ซ  Hotspot Site Investigation (HSI), which
                     ranks the potential severity of each
                     commercial, industrial, institutional,
                     municipal or transport-related hotspot
                     site found within a subwatershed

                  •  Analysis of Streets and Storm
                     Drains (SSD), which measures the
                     average pollutant accumulation in the
                     streets, curbs, and catch basins of a


                  The desktop analysis method screens local
                  business and permit databases to identify
                  specific commercial, industrial, institutional,
                  municipal, and transport-related sites that
                  are known to have a higher risk of producing
                  illicit discharges. Chapter 5 and Appendix A
                  provide discussions of this analysis.


                  Many common neighborhood behaviors can
                  cause transitory discharges that are  seldom
                  defined or regulated as illicit discharges
                  by most communities. Individually,  these
                  behaviors cause relatively small discharges,
                  but collectively, they can produce significant
Illicit Discharge Detection and Elimination: A Guidance Manual

                                                     Chapter 9: Preventing Illicit Discharges
pollutant loads. Most communities use
outreach and education to promote pollution
prevention practices, and some of the
more effective practices to influence these
behaviors are described in this section:

•   Storm drain stenciling

•   Septic system maintenance

•   Vehicle fluid changing

•   Car washing

•   Household hazardous waste storage and

•   Swimming pool draining

Storm Drain Stenciling

Storm drain stenciling sends a clear message
to keep trash and debris, leaf litter, and
pollutants out of the storm drain system, and
may deter illegal dumping and discharges
(Figure 14). Stenciling may increase water-
shed awareness and neighborhood steward-
ship and can be used in any neighborhood
with enclosed storm drains.

Stenciling is an excellent way to involve
the public, and just a few trained volunteers
can systematically stencil all the storm
drains within a neighborhood in a short
time. Volunteers can be recruited from
scouting, community service, and watershed
organizations, or from high schools and
                    — .  '  '    ••
   Figure 14: Storm drain stenciling may
       help reduce illicit discharges.
neighborhood associations. Program
managers should designate a staff person
to coordinate storm drain stenciling and
be responsible for recruiting, training,
managing, and supplying volunteers.

Storm drain stenciling programs are
relatively inexpensive. Most communities
use stencils, although some are now using
permanent markers made of tile, clay, or
metal. Stencils cost about 45 cents per linear
inch and can be used for 25 to 500 drains,
depending on whether paint is sprayed or
applied with a brush or roller. Permanent
signs are generally more costly; ceramic
tiles cost $5 to $6 each and metal stencils
can cost $100 or more. More guidance on
designing a stenciling program can be found
in Schueler et al. (2004).

Septic  System Maintenance

Failing septic systems can be a major source
of bacteria, nitrogen, and phosphorus,
depending on the overall density of systems
present in a subwatershed (Swann, 2001).
Failure results in illicit surface or subsurface
discharges to streams. According to U.S.
EPA (2002), more than half of all existing
septic systems are more than 30 years old,
which is well past their design life. The same
study estimates that about 10%  of all septic
systems are not functioning properly at any
given time, with even higher failure rates in
some regions and soil conditions.

Septic systems are a classic case of out of
sight and out of mind. Many owners take
their septic systems for granted, until they
back up or break out on the surface of their
lawn. Subsurface failures, which are  the
most common, go unnoticed. In addition,
inspections, pump outs, and repairs can be
costly, so many homeowners tend to put off
the  expense until there is a real problem.
Lastly, many septic system owners are not
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 9: Preventing Illicit Discharges
                                    CASE STUDY
 In 1997, Madison County, NC implemented a project to address straight piping problems.
    In 1999, a survey identified 205 households with black water straight-piping (toilet
   waste), 243 households with gray water straight-piping (sink, shower, washer waste),
   and 104 households with failing septic systems. The project facilitated more than 10
   community meetings, and issued more than 20 educational articles on straight-piping
  and water quality in the local papers. In addition, the project leveraged $903,000 from
  the N.C. Clean Water Management Trust Fund to establish a Revolving Loan and Grant
  Program for low and moderate income county residents that need assistance installing a
  septic system or repairing a failing one. (Land of Sky Regional Council website, 2002).
aware of the link between septic systems
and water quality. Communities can employ
a range of tools to improve septic system
maintenance. These include:

•  Media campaigns and conventional
   outreach materials to increase awareness
   about septic  system maintenance and
   water quality (e.g., billboards, radio,
   newspapers, brochures, bill inserts, and

•  Discount coupons for septic system

•  Low interest loans for septic system

•  Mandatory inspections

•  Performance certification upon property

•  Creation of septic management districts

•  Certification and training of operation/
   maintenance professionals

•  Termination of public services for failing

Vehicle Fluid Changing

Dumping of automotive fluids into storm
drains can cause major water quality
problems, since  only a few quarts of oil
or a few gallons of antifreeze can severely
                 degrade a small stream. Dumping delivers
                 hydrocarbons, oil and grease, metals, xylene
                 and other pollutants to streams, which can
                 be toxic during dry-weather conditions when
                 existing flow cannot dilute these discharges.
                 The major culprit has been the backyard
                 mechanic who changes his or her own
                 automotive fluids (Figure 15). Communities
                 have a range of tools to prevent illegal
                 dumping of car fluids, including:

                 •  Outreach materials distributed at auto
                    parts store and service stations

                 •  Community oil recycling centers

                 •  Directories of used oil collection stations

                 •  Free or discounted oil disposal

                 •  Pollution hotlines

                 •  Fines and other enforcement actions
                                                Figure 15: Home mechanic changing his
                                                          automotive fluids
Illicit Discharge Detection and Elimination: A Guidance Manual

                                                    Chapter 9: Preventing Illicit Discharges
Car Washing

Car washing is a common neighborhood
behavior that can produce transitory
discharges of sediment, nutrients and other
pollutants to the curb, and ultimately the
storm drain. Communities have utilized
many innovative outreach tools to promote
environmentally safe car washing, including:

•  Media campaigns

•  Brochures promoting nozzles with shut
   off valves

•  Storm drain plug and wet vac provisions
   for charity car wash events

•  Water bill inserts promoting
   environmentally safe car washing

•  Discounted tickets for use at commercial
   car washes

Household Hazardous  Waste
Storage and Disposal

The average garage contains a lot of
products that are classified as hazardous
wastes, including paints, stains, solvents,
used motor oil, pesticides and cleaning
products. While some household hazardous
waste (HHW) may be  dumped into storm
drains, most enters the storm drain system
as a result of outdoor rinsing and cleanup.
Improper disposal of HHW can result in
acute toxicity to downstream aquatic life.
The desired neighborhood behavior is  to
participate in HHW  collection days, and
to use appropriate pollution prevention
techniques when conducting rinsing,
cleaning and fueling operations (Figure 16).

Convenience and awareness appear to be
the critical factors in getting residents  to
participate in household hazardous waste
collection programs. Participation depends
  Figure 16: Household hazardous wastes
   should be properly contained to avoid
            indirect discharges

on the number of days each year collection
events are held and is inversely related to
both the distance homeowners must travel to
recycle waste and the restrictions on what is
accepted. Communities have used a variety
of techniques to promote and expand HHW
collection, including:

•  Mass media campaigns to educate
   residents about proper outdoor cleaning/
   rinsing techniques

•  Conventional outreach materials
   notifying residents about HHW and
   collection days

•  More frequent HHW collection days

•  Providing curbside disposal options for
   some HHW

•  Establishing permanent collection
   facilities at solid waste facilities

•  Providing mobile HHW pickup

•  Waiving disposal fees at landfills

Swimming Pool Draining

Routine and end-of-season maintenance
tasks for aboveground or in-ground pools
can cause the discharge of chlorinated water
or filter back flush water into the storm drain
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 9: Preventing Illicit Discharges

system or the stream (Figure 17). The ideal
practice is to discharge chlorinated pool
water into the sanitary sewer system, or
hold it until chlorine and temperature levels
are acceptable to permit spreading it over a
suitable pervious surface.

Most pool owners understand that regular
maintenance is essential to keep pools safe
and clean, and they may be more receptive
to changing discharge behaviors with proper
education. Effective outreach methods

•  Conventional outreach techniques on
   proper discharge (pamphlets, water bill
   inserts, posters)

•  Educational kiosks at the retail outlets
   selling pool chemicals

•  Changes in local plumbing codes to
   require discharge to sanitary sewer

•  Local ordinances that allow for fines/
   enforcement for  unsafe pool discharges
                  9.4    Preventing Illicit Discharges
                  from Generating Sites

                  Many indirect discharges can be identified
                  and prevented using the concept of
                  generating sites, which are a small subset
                  of commercial, industrial, institutional,
                  municipal and transport-related operations
                  that have the greatest risk of generating
                  indirect discharges. Program managers
                  should become intimately familiar with
                  the types of generating sites found in their
                  community, particularly those regulated
                  by industrial NPDES storm water permits.
                  Some of the more common operations that
                  generate spills and transitory discharges are
                  profiled in Table 27.

                  Most communities consider nearly all non-
                  storm water discharges from generating
                  sites to be illicit, and take a more regulatory
                  approach. Consequently, pollution
                  prevention practices are more prescriptive,
                  and are frequently incorporated into a
                  pollution prevention plan for a facility or
                  operation. Like anyone else, businesses
                  respond better to carrots than sticks, but
                  often need both. Communities possess four
                  broad tools to promote effective pollution
                  prevention practices at generating sites:

                  •  Business outreach and education

                  •  Spill prevention and response planning

                  •  Employee training

                  •  Site inspections
    Figure 17: Swimming pools can be a
        source of illicit discharges.
Illicit Discharge Detection and Elimination: A Guidance Manual

                                                       Chapter 9: Preventing Illicit Discharges
                 Table 27: Common Discharges Produced at Generating Sites
          Generating Site
            Activity Generating the Discharge
         Vehicle Operations
     (Maintenance, Repair, Fueling,
          Washing, Storage)
  Improper disposal of fluids down shop and storm drains
  Spilled fuel, leaks and drips from wrecked vehicles
  Hosing of outdoor work areas
  Wash water from cleaning
         Outdoor Materials
  (Loading/unloading, Outdoor storage)
  Liquid spills at loading areas
  Hosing/washing of loading areas into shop or storm drains
  Leaks and spills of liquids stored outside
        Waste Management
    (Spill prevention and response,
       Dumpster management)
  Spills and leaks of liquids
  Dumping into storm drains
  Leaking dumpsters
     Physical Plant Maintenance
   (Building Repair, Remodeling and
 maintenance, Parking lot maintenance)
  Discharges from power washing and steam cleaning
  Rinse water and wash water discharges during cleanup
  Runoff from degreasing and re-surfacing
       Turf and Landscaping
          (Turf Management
      Landscaping/Grounds care)
  Non-target irrigation
  Improper rinsing of fertilizer/pesticide applicators
     Unique Hotspot Operations
     (Pools, Golf Courses, Marinas,
      Construction, Restaurants,
            Hobby farms)
• Discharge of chlorinated water from pools
• Dumping of sewage and grease
Business Outreach and Education

Targeted distribution of educational
materials to specific business sectors in the
subwatershed is the most common method
of promoting pollution prevention. Outreach
materials are designed to educate owners
and employees about polluting behaviors,
recommend appropriate pollution prevention
practices, and notify them of any local or
state regulations. Useful outreach materials
include brochures, training manuals, posters,
directories of pollution prevention vendors,
and signs. Passive business outreach works
best when it is specially adapted and
targeted to a specific business sector (e.g.,
vehicle repair, landscaping, restaurants) and
is routinely and directly presented to local
business groups and trade associations.
Business outreach materials require
              employees to read or hear them, and then
              take active steps to change their behavior.

              Communities can also provide direct
              technical assistance to develop a customized
              pollution prevention prescription for
              individual generating sites. In this case,
              local staff work closely with owners and
              operators to inspect the site and develop
              an effective  pollution prevention plan. In
              other cases,  pollution prevention workshops
              or model plans are offered to businesses
              and trade groups that represent specific
              groups of generating sites. In either case,
              the locality acts as a technical partner to
              provide ongoing consultation to individual
              businesses to support their pollution
              prevention efforts.
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 9: Preventing Illicit Discharges
Spill Prevention and Response

A spill prevention and response plan is
useful for any potential generating site,
and is mandatory for any operation that
uses, generates, produces, or transports
hazardous materials, petroleum products or
fertilizers. These operations are known as
SARA 312 operators and are regulated by
state environmental agencies. In addition,
all industrial sites regulated by individual
or group NPDES storm water permits
must have an updated spill prevention
and response plan on its premises. Spill
containment and response plans should
also be prepared for major highways that
cross  streams and other water bodies, since
truck and tanker accidents often represent
the greatest potential spill risk in most
communities (Figure 18).

Spill prevention and response plans describe
the operational procedures to reduce the
risks of spills and accidental discharge and
ensure that proper controls are in place in
the event they do occur.  Spill prevention
plans standardize everyday procedures and
rely on employee training to reduce potential
liability, fines and costs associated with
clean up. Planning begins with an analysis
of how pollutants are handled at the site and
how they interact with storm water. Spill
prevention and response plans have five
major components:

1. A site map and evaluation of past spills
   and leaks

2. An inventory of materials at the site

3. Identification of potential spill areas

4. A list of required spill response

5. Employee training
                  When spills do occur, a good spill
                  prevention and response plan will clearly:

                  •  Identify potential spill sites and their
                     drainage points

                  •  Specify material handling procedures

                  •  Describe spill response procedures

                  •  Ensure that adequate spill clean-up
                     equipment is available

                  Employee Training

                  Effective and repeated employee training is
                  essential to maintain pollution prevention
                  practices at generating sites. Indeed,
                  continuous  employee training is an essential
                  component of any pollution prevention
                  plan, particularly at generating sites where
                  the work force turns over frequently.
                  Many businesses perceive time devoted to
                  pollution prevention training as reducing
                  their bottom line, and may be hesitant to
                  develop training materials or allocate time
                  for training. In some cases, local agencies
                  supply free or low cost videos, posters,
                  shop signs,  or training brochures  (often in
                  multilingual formats). In other cases, short
                  training classes are offered for employees
                  or supervisors that are scheduled  for down
                  times of the year (e.g., winter classes for
                  landscaping companies or construction
                  contractors) or coincide with regular
                  employee safety meetings.
                           Figure 18: Spill response
                            often involves portable
                              booms and pumps
Illicit Discharge Detection and Elimination: A Guidance Manual

                                                     Chapter 9: Preventing Illicit Discharges
Program managers can refer to Schueler et
al. (2004) for more guidance on developing
effective pollution practices at generating
sites and storm water hotspots. Employee
training should be conducted at least
annually to educate workers on the proper
practices to avoid illicit discharges and
respond to spills. Training can be reinforced
with signs, and posters.


Regular inspections of generating sites are
a key tool to foster pollution prevention
and reduce the risk of illicit discharges.
Communities that possess an MS4 permit
should ensure that they have the authority
to inspect non-regulated sites that connect
to the municipal storm drain system they
operate. These inspections can be used to
assess the site and educate owners/operators
about recommended pollution prevention
practices. Site inspections are staff intensive
and therefore are best suited to high-risk
generating sites.

An industrial NPDES storm water permit
is an extremely important compliance tool
at many generating sites. NPDES permits
require operators to prepare a pollution
prevention plan for the site and implement
the practices specified in the plan. Significant
penalties can be imposed for non-compliance.

To date, compliance with the industrial storm
water permit program has been spotty, and
a significant fraction of regulated industries
has failed to file their required permits.
According to  Duke and Shaver (1999) and
Pronold (2000), as many as 50% of industrial
sites that are required to have a permit do
not actually have one. These sites are termed
"non-filers," and are often small businesses or
operations that are unaware of the relatively
new regulations. It is therefore  quite likely
that many hotspots in a subwatershed may not
have a valid NPDES permit. These operations
should be educated about the industrial
permit program, and encouraged to apply
for permit coverage. Non-filers should be
referred to the NPDES permitting authority
for details on how to obtain permit coverage.

Inspections are an important stick to
improve compliance at generating sites
subject to industrial NPDES permits.
Inspectors should frequently observe site
operations to ensure that the right mix of
pollution prevention practices is routinely
employed. Communities with MS4 permits
have the authority to inspect storm water
NPDES sites that discharge to their storm
drain system, and refer any violations for
subsequent state or federal enforcement.

Voluntary inspections of non-regulated
generating sites are a good tool to educate
owners/operators about recommended
pollution prevention practices. When
generating sites are inspected, existing fire,
building or health inspectors should be
considered  since they are already acquainted
with how to deal with small businesses.


Many municipal operations and services
have the potential to create or reduce illicit
discharges. Program managers should
review all municipal operations and
services to make sure good housekeeping
is practiced. In addition, program managers
should examine:

•  Routine sewer and storm drain

•  Plumbing code revisions

ป  HHW collection services

*  Used motor oil collection services
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 9: Preventing Illicit Discharges
Failure to regularly inspect and maintain local
sewer and storm water infrastructure can
cause illicit discharges to receiving waters.
Within the  storm drain system, maintenance
should focus on frequent cleaning to keep
trash, debris and illegally dumped material
from entering the storm drain system. In the
sanitary sewer network, maintenance should
focus on  finding damaged infrastructure that
allows sewage discharges from the sanitary
sewer. In-stream monitoring, historical data
reviews of past complaints, or aging sewer
infrastructure can often be used to identify
likely problem areas.8

Communities need to establish the legal
authority to prohibit illicit connections to
the storm drain system.  When the illicit
discharge ordinance is being prepared,
communities should thoroughly review
all of their plumbing codes to prevent any
misinterpretation that might create cross
connections to the storm drain system.
Program managers should also specifically
target licensed plumbers to educate them on
any code changes.

Households generate a lot of hazardous
wastes, and communities need to educate
residents about proper household hazardous
waster (HHW) handling and disposal, and
provide convenient options for pick up and
disposal. Communities have experimented
8 Preliminary sewer system investigations are not discussed
further in this manual. For more detail on how to conduct
these investigations consult the EPA handbook, "Sewer
System Infrastructure Analysis and Rehabilitation."
(U.S. EPA, 1991)
with several innovative ways to deal with
HHW including:

•   A permanent facility that accepts HHW
    year-round and can serve as a central
    location for HHW exchange and recycling

ป   Mobile collection at temporary facilities.
    On designated special collection
    days, mobile units can move through
    communities accepting HHW and take
    the form of curbside pickup or central
    collection locations

•   Some local businesses may act as drop
    off centers for certain products. Some
    local garages, for example, may accept
    used motor oil for recycling

Overall, the costs for implementing HHW
collection programs can be high. Factors
such as frequency of the collection, size of
community, environmental awareness, level
of staff training, and level of outreach all
contribute to the overall cost. Participation
in collection programs usually ranges from
1% to 5% of the population (HGAC, 2001),
and the cost per participant can vary greatly
(Table 28).


Used motor oil collection has been a common
municipal service for many years, however,
program managers may need to refine their
programs to increase participation. Suggested
outreach approaches include:

•   Conventional outreach materials
    provided at points of sale (e.g., auto parts
    stores, service  stations)

ป   Multilingual outreach materials

ป   Directories of used oil collection stations

•   Free or discounted oil disposal
                               Illicit Discharge Detection and Elimination: A Guidance Manual

                                                  Chapter 9: Preventing Illicit Discharges
                                   CASE STUDY
      The City of Denver operates a pilot, door-to-door collection program to assist
    residents in the proper disposal and recycling of HHW. To be eligible for collection,
   residents must currently be receiving trash collection service from City Solid Waste
    Management crews. Residents are permitted one HHW collection annually and are
  asked to have  at least three different materials before calling for a pickup. Residents
   then receive a collection date and an HHW Kit that holds up to 75 pounds. Residents
  are instructed  on what  items can be placed inside the Kit, and can have additional items
   picked up for a small fee. The program also educates citizens on how to prevent the
  accumulation of chemicals in the home environment. The key element of this service is
   convenience for area residents. Customers can make a phone call, put their waste in a
                container, and schedule a pickup (City of Denver, 2003).
Table 28: Summary of Local Household Hazardous Waste Collection Programs
Fort Worth TX
Monmouth County,
NJ (2002)
Nashville, TN (2002)
Putnam County, NY
Town of East
Hampton, NY (1997)
26 cities
Cost per
Program Description
Accept 3 days a week at
permanent facility, plus
approx 24 mobile units
Permanent facility plus
2-3 remote days
361 day drop off at
permanent facility
One collection day per
Three collection days per
                                   CASE STUDY
  Municipal cross-training is a proven and effective tool for identifying illicit discharges.
  Wayne County, Michigan has a very active IDDE program that has included efforts to
  train all County "field" staff to identify and report suspicious discharges in the course
 of their duties. The Illicit Discharge Elimination Training Program includes presentations
     for general field staff that instructs them in the identification and reporting of
    suspicious discharges. To date, 734 people from various agencies and communities
 throughout Michigan have attended the training sessions (Tuomari and Thompson, 2002).
    The information these individuals gained from attending the training session helped
   identify 82 illicit discharges in the counties of Oakland, Washtenaw, and Wayne. Road
    division staff trained in recognizing  illicit discharges discovered 12 septic systems in
 Wayne County that were failing or had direct discharges to surface water. Other counties
    found 70 illicit discharges during their investigations. The elimination of these illicit
  discharges will prevent an estimated 3.5 million gallons of polluted water from reaching
   Michigan surface waters each  year (associated load reductions are estimated at 7,200
  pounds/year of Biological Oxygen Demand and 25, 000 Ibs/yr of Total Suspended Solids)
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 9: Preventing Illicit Discharges
9.6    Budgeting and Scoping
Pollution Prevention

The cost of preventing illicit discharges is
directly related to the scope of the education
effort. Larger communities often employ
education staff on a full-time basis, or at
least have one staff member who spends
much of their time doing outreach on
issues such as illicit discharges. Smaller
communities often spread the education
effort out over several departments, and try
to use already established programs such as
                 cooperative extensions or citizen watershed
                 groups. Table 29 provides some cost data for
                 storm water education in one community.

                 In reality, program managers have to do a
                 lot of homework to scope and budget their
                 pollution prevention education program.
                 Normally, these education efforts are
                 integrated with other storm water education
                 programs. One of the best tools to develop
                 an overall education budget is the Source
                 Control Plan, which is described in Schueler
                 et al. (2004).
Table 29: Estimated Costs for Public Awareness Program Components
(Adapted from Wayne County, Ml. 2001)
Education Component
Information Brochures
Technical Manuals
Business Education
Program Planning and
Estimated Cost
$100/hour for development
$0.10-$0.20/pamphlet for black and white printing
$0.30/pamphlet for mailing
$100/hour for development
$100.00/manual for printing
$50/hour for business/activity list
$100/hour for development
$50/hour for employee presentation
$10,000 per year
160-320 hours
160-480 hours
40-80 hours for compilation
80-1 60 hours for
8 hours for presentation,
including prep time.
0.2 Full Time Equivalents
(FTE) per year
Source: Wayne County, Ml. 2001. Planning and Cost Estimating Criteria for Best Management Practices. Rouge River Wet
Weather Demonstration Project. TR-NPS25.00
Illicit Discharge Detection and Elimination: A Guidance Manual

                                       Chapter 10: IDDE Program Tracking and Evaluation
                      Chapter 10: IDDE  Program Tracking
                                       and Evaluation
Purpose: This last program component
addresses the ongoing management of the
IDDE program and reviews progress made
in meeting the measurable program goals
established earlier in the permit cycle.
Adaptive management is critical since
most communities initially have a poor
understanding of the scope and nature of
their illicit discharge problem. Frequent
program review can ensure that the most
severe illicit discharges are eliminated
in the most cost-effective way during the
permit cycle. Program evaluation should
also be directly tied to program goals (see
Chapter 6 on Developing Program Goals and
Implementation Strategy)

Method(s): The primary method is frequent
maintenance and analysis of the IDDE
tracking system developed as part of the
program. The integrated tracking system
contains geospatial data on ORI results,
indicator monitoring, on-site investigations,
dumping and spill sites and hotline calls.
The tracking system is important from both
an enforcement and program evaluation
standpoint. Each of the eight program
components should be reviewed annually
and prior to new permit negotiation, using
data collected, compiled, and assessed from
the tracking system.
Desired Product or Outcome(s): Updated
tracking database and annual report with
summary of progress to date, findings,
recommendations for program revisions, and
work plan (including milestones and goals)
for the upcoming year.

Budget and/or Staff Resources Required:
Program assessment is an ongoing
responsibility of the program manager. The
staff effort to prepare an annual report is
about three to four weeks. In general, the
first annual report will require more effort
than subsequent ones.

Integration with Other Programs: Program
managers should always consider other
programs and regulatory requirements when
assessing program performance and revising
goals. At a minimum, the annual report
should be shared with other departments
and agencies to head off duplication of
efforts and to look for opportunities to pool
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter JO: IDDE Program Tracking and Evaluation

An accurate and user-friendly system to
track, report and respond to illicit discharge
problems is critical for program managers.
Ideally, the tracking system should be
designed and operational within the first
year of the program. The tracking system
enables managers to measure program
indicators, and gives field crews a home to
store the data they collect. The ideal tracking
system consists of a relational database that
is linked to a GIS system, which can be used
to store and analyze data and produce maps.

The fundamental units to track are
individual outfalls, along with any
supporting information about their
contributing drainage area. Some of the
key information to include  when tracking
outfalls includes:

•  Geospatial coordinates  of each outfall

•  The subwatershed and watershed address

ซ  Any supporting information about the
   contributing land use

•  Diameter and physical characteristics of
   the outfall

•  Outfall Reconnaissance Inventory (ORI)
   data, as it is collected

•  Any accompanying digital photos

ซ  Any follow-up monitoring at the outfall
   or further up the pipe

•  Any hotline complaints logged for the
   outfall, along with the local response

•  Status and disposition of any
   enforcement actions

•  Maintenance and inspection data
10.2             the

Since IDDE programs are a first time
endeavor for many communities, program
managers need to be extremely adaptable in
how they allocate their resources. Effective
IDDE programs are dynamic and flexible to
respond to an ever-changing set of discharge
problems, program obstacles, and emerging
technologies. At a minimum, program
managers should maintain and evaluate
their IDDE tracking system annually, and
modify program components as needed.
Tracking systems should be designed so
that progress toward measurable goals
(see Chapter 6) can be easily reported.
Communities that develop and maintain
a comprehensive tracking system should
realize program efficiencies. The tracking
system should contain the following features
at a minimum:

ป  Updated mapping to reflect outfalls
   located during the ORI

•  Surveyed stream reaches with locations
   of obvious, suspect, and potential
   discharges, and locations of dumping

*  Indicator sampling results for specific
   streams, outfalls and storm drains

•  Frequency of hotline use and associated
   number of "hits" or  confirmed illicit

ซ  Costs for each of the eight program
   components (e.g., office, field, lab,
   education, enforcement, etc.)

•  Number of discharges corrected

•  Status and disposition of enforcement

Regular analysis  of the tracking system
sheds light on program  strengths and
                              Illicit Discharge Detection and Elimination: A Guidance Manual

                                         Chapter 10: /DDE Program Tracking and Evaluation
deficiencies, and improves targeting of
limited program resources. For example,
if hotline complaints are found to uncover
the most severe illicit discharge problems,
program managers may want to allocate
more resources to increase public awareness
about the hotline, and shift resources from
outfall screening and indicator monitoring.
Illicit Discharge Detection and Elimination: A Guidance Manual                           89

Chapter JO: /DDE Program Tracking and Evaluation
90                          Illicit Discharge Detect/on and Elimination: A Guidance Manual

                                          Chapter 11: The Outfall Reconnaissance Inventory
Chapter  11: The Outfall  Reconnaissance Inventory
This chapter describes a simple field
assessment known as the Outfall
Reconnaissance Inventory (ORI). The ORI
is designed to fix the geospatial location and
record basic characteristics of individual
storm drain outfalls, evaluate suspect
outfalls, and assess the severity of illicit
discharge problems in a community. Field
crews should walk all natural and man-
made streams channels with perennial and
intermittent flow, even if they do not appear
on available maps (Figure 19). The goal
is to complete the ORI on every stream
mile in the MS4 within the first permit
cycle, starting with priority subwatersheds
identified during the desktop analysis.
The results of the ORI are then used to
help guide future outfall monitoring and
discharge prevention efforts.

11.1   Getting Started

The ORI requires modest mapping, field
equipment, staffing and training resources.
A complete list of the required and optional
resources needed to perform an ORI is
presented in Table 30. The ORI can be
combined with other stream assessment
tools, and may be supplemented by simple
indicator monitoring. Ideally, a Phase II
community should plan on surveying its
entire drainage network at least once over
the course of each five-year permit cycle.
Experience suggests that it may take up to
three stream walks to identify all outfalls.

Best Times to Start

Timing is important when scheduling ORI
field work. In most regions of the country,
spring and fall are the best seasons to perform
the ORI. Other seasons typically have
challenges such as over-grown vegetation or
high groundwater that mask illicit discharges,
or make ORI data hard to interpret9.

Prolonged dry periods during the non-
growing season with low groundwater levels
are optimal conditions for performing an ORI.
Table 31 summarizes some of the regional
factors to consider when scheduling ORI
surveys in your community. Daily weather
patterns also determine whether ORI field
work should proceed. In general, ORI field
work should be conducted at least 48 hours
after the last runoff-producing rain event.

Field Maps

The field maps needed for the ORI are
normally generated during the desktop
assessment phase of the IDDE program
described in Chapter 5. This section
     Figure 19: Walk all streams and
       constructed open channels
9 Upon initial program start-up, the ORI should be conducted
during periods of low groundwater to more easily identify
likely illicit discharges. However, it should be noted that high
water tables can increase sewage contamination in storm
drain networks due to infiltration and inflow interactions.
Therefore, in certain situations, seasonal ORI surveys may
be useful at identifying these types of discharges. Diagnosis
of this source of contamination, however, can be challenging.
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 11: The Outfall Reconnaissance Inventory
                        Table 30: Resources Needed to Conduct the ORI
  Need Area
           Minimum Needed
          Optional but Helpful
• Roads
• Streams
  Known problem areas
  Major land uses
  Specific industries
  Storm drain network
  SIC-coded buildings
  5 one-liter sample bottles
  Camera (preferably digital)
  Cell phones or hand-held radios
  Clip boards and pencils
  Field sheets
  First aid kit
  Flash light or head lamp
  GPS unit
  Spray paint (or other marker)
  Surgical gloves
  Tape measure
  Temperature probe
  Waders (snake proof where necessary)
  Watch with a second hand
  Portable Spectrophotometer and
  reagents (can be shared among crews)
  Insect repellant
  Sanitary wipes or biodegradable soap
  Wide-mouth container to measure flow
  Test strips or probes (e.g., pH and
• Basic training on field methodology
• Minimum two staff per crew
• Ability to track discharges up the
  drainage system
• Knowledge of drainage area, to identify
  probable sources.
• Knowledge of basic chemistry and
Table 31: Preferred Climate/Weather Considerations for Conducting the ORI
Preferred Condition
Low groundwater (e.g.,
very few flowing outfalls)
No runoff-producing rainfall
within 48 hours
Dry Season
Leaf Off
High groundwater can
confound results
Reduces the confounding
influence of storm water
Allows for more days of
field work
Dense vegetation makes
finding outfalls difficult
Notes/Regional Factors
In cold regions, do not conduct the ORI in the
early spring, when the ground is saturated from
The specific time frame may vary depending on
the drainage system.
Applies in regions of the country with a "wet/
dry seasonal pattern." This pattern is most
pronounced in states bordering or slightly interior
to the Gulf of Mexico or the Pacific Ocean.
Dense vegetation is most problematic in the
southeastern United States.
This criterion is helpful but not required.
                Illicit Discharge Detection and Elimination: A Guidance Manual

                                          Chapter 11: The Outfall Reconnaissance Inventory
provides guidance on the basic requirements
for good field maps. First, ORI field maps
do not need to be fancy. The scale and
level of mapping detail will vary based on
preferences and navigational skills of field
crews. At a minimum, maps should have
labeled streets and hydrologic features
(USGS blue line streams, wetlands, and
lakes), so field crews can orient themselves
and record their findings spatially.

Field maps should delineate the contributing
drainage area to major outfalls, but only if
they are readily available.  Urban landmarks
such as land use, property boundaries, and
storm drain infrastructure are also quite
useful in the field. ORI field maps should be
used to check the accuracy and quality of
pre-existing mapping information, such as
the location of outfalls and stream origins.

Basic street maps offer the advantage of
simplicity, availability, and well-labeled
road networks and urban landmarks.
Supplemental maps such as a 1": 2000'
scale USGS Quad sheet or finer scale aerial
photograph are also recommended for
the field. USGS Quad sheets are readily
available and display major transportation
networks and landmarks, "blue line"
streams, wetlands, and topography. Quad
maps may be adequate for less developed
subwatersheds, but are not always accurate
in more urban subwatersheds.

Recent aerial photographs may provide
the best opportunity to navigate the
subwatershed and assess existing land
cover. Aerial photos, however,  may lack
topography and road names, can be costly,
and are hard to record field notes on due to
their darkness. GIS-ready aerial photos and
USGS Quad sheets can be downloaded from
the internet or obtained from local planning,
parks, or public works agencies.
ORI field sheets are used to record
descriptive and quantitative information
about each outfall inventoried in the field.
Data from the field sheets represent the
building blocks of an outfall tracking system
allowing program managers to improve
IDDE monitoring and management. A
copy of the ORI field sheet is provided
in Appendix D, and is also available as
a Microsoft Word™ document. Program
managers should modify the field sheet
to meet the specific needs and unique
conditions in their community.

Field crews should also carry an
authorization letter and a list of emergency
phone numbers to report any emergency
leaks, spills, obvious illicit discharges
or other water quality problems to the
appropriate local authorities directly from
the field. Local law enforcement agencies
may also need to be made aware of the
field work. Figure 20 shows an example of
a water pollution emergency contact list
developed by Montgomery County, MD.

Basic field equipment needed for the ORI
includes waders, a measuring tape, watch,
camera, GPS unit, and surgical gloves (see
Table 30). GPS units and digital cameras are
usually the most expensive equipment items;
however, some local agencies may already
have them for other applications. Adequate
ranging, water-resistant, downloadable
GPS units can be purchased for less than
$150.  Digital cameras are preferred and
can cost between $200 and $400, however,
conventional or disposable cameras can also
work, as long as they have flashes. Hand-
held data recorders and customized software
can be used to record text, photos, and GPS
coordinates electronically in the field. While
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 11: The Outfall Reconnaissance Inventory
these technologies can eliminate field sheets
and data entry procedures, they can be quite
expensive. Field crews should always carry
basic safety items, such as cell phones,
surgical gloves, and first aid kits.


The ORI requires at least a two-person
crew, for safety and logistics. Three person
crews provide greater safety and flexibility,
which helps divide tasks, allows one person
to assess adjacent land uses, and facilitates
tracing outfalls to their source. All crew
members should be trained on how to
complete the ORI and should have a basic
understanding of illicit discharges and their
water quality impact. ORI crews can be
staffed by trained volunteers, watershed
groups and college interns. Experienced
crews can normally expect to cover two to
three stream miles per day, depending on
stream access and outfall density.
                  11.2   Desktop Analysis to
                  Support the ORI

                  Two tasks need to be done in the office
                  before heading out to the field. The major
                  ORI preparation tasks include estimating
                  the total stream and channel mileage in the
                  subwatershed and generating field maps. The
                  total mileage helps program managers scope
                  out how long the ORI will take and how
                  much it will cost. As discussed before, field
                  maps are an indispensable navigational aid
                  for field crews working in the subwatershed.

                  Delineating Survey Reaches

                  ORI field maps should contain a preliminary
                  delineation of survey reaches. The stream
                  network within your subwatershed should
                  be delineated into discrete segments of
                  relatively uniform character. Delineating
                  survey reaches provides good stopping
                  and starting points for field crews, which
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                Figure 20: Example of a comprehensive emergency contact list
                               for Montgomery County, MD
Illicit Discharge Detection and Elimination: A Guidance Manual

                                           Chapter 11: The Outfall Reconnaissance Inventory
is useful from a data management and
logistics standpoint. Each survey reach
should have its own unique identifying
number to facilitate ORI data analysis and
interpretation. Figure 21 illustrates some
tips for delineating survey reaches, and
additional guidance is offered below:
•  Survey reaches should be established
   above the confluence of streams and
   between road crossings that serve as a
   convenient access point.
•  Survey reaches should be defined at the
   transition between major changes in land
   use in the stream corridor (e.g. forested
   land to commercial area).
•  Survey reaches should generally
   be limited to a quarter mile or less
   in length. Survey reaches in lightly
    developed subwatersheds can be
    longer than those in more developed
    subwatersheds, particularly if uniform
    stream corridor conditions  are expected
    throughout the survey reach.
•   Access through private or public
    property should be considered when
    delineating survey reaches  as permission
    may be required.

It should be noted that initial field maps
are not always accurate, and changes may
need to be made in the field to adjust survey
reaches to account for conditions such as
underground streams, missing  streams or
long culverts. Nevertheless, upfront time
invested in delineating survey reaches makes
it easier for field crews to perform the ORI.
   Figure 21: Various physical factors control how survey reaches are delineated, (a) Survey reaches
   based on the confluence of stream tributaries, (b) A long tributary split into % mile survey reaches.
     (c) Based on a major road crossing (include the culvert in the downstream reach), (d) Based on
  significant changes in land use (significant changes in stream features often occur at road crossings,
             and these crossings often define the breakpoints between survey reaches).
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 11: The Outfall Reconnaissance Inventory
11.3  Completing the ORI

Field crews conduct an ORI by walking
all streams and channels to find outfalls,
record their location spatially with a GPS
unit and physically mark them with spray
paint or other permanent marker. Crews also
photograph each outfall and characterize its
dimensions, shape, and component material,
and record observations on basic sensory
and physical indicators. If dry weather flow
occurs at the outfall, additional flow and
water quality data are collected. Field crews
may also use field probes or test strips to
measure indicators such as temperature, pH,
and ammonia at flowing outfalls.

The ORI field sheet is divided into eight
sections that address both flowing  and non-
flowing outfalls (Appendix D). Guidance
on completing each section of the ORI field
sheet is presented below.
                  Outfalls to Survey

                  The ORI applies to all outfalls encountered
                  during the stream walk, regardless of
                  diameter, with a few exceptions noted in
                  Table 32. Common outfall conditions seen
                  in communities are illustrated in Figure 22
                  As a rule, crews should only omit an outfall
                  if they can definitively conclude it has no
                  potential to contribute to a transitory illicit
                  discharge. While EPA's Phase I guidance
                  only targeted major outfalls (diameter of 36
                  inches or greater), documenting all outfalls
                  is recommended, since smaller pipes make
                  up the majority of all outfalls and frequently
                  have illicit discharges (Pitt et a/., 1993 and
                  Lalor, 1994). A separate ORI field sheet
                  should be completed for each outfall.
                         Table 32: Outfalls to Include in the Screening
                 Outfalls to Record
                                 Outfalls to Skip
   Both large and small diameter pipes that appear to be
   part of the storm drain infrastructure
   Outfalls that appear to be piped headwater streams
   Field connections to culverts
   Submerged or partially submerged outfalls
   Outfalls that are blocked with debris or sediment
   Pipes that appear to be outfalls from storm water
   treatment practices
   Small diameter ductile iron pipes
   Pipes that appear to only drain roof downspouts but that
   are subsurface, preventing definitive confirmation
                       Drop inlets from roads in culverts (unless
                       evidence of illegal dumping, dumpster
                       leaks, etc.)
                       Cross-drainage culverts in transportation
                       right-of-way (i.e., can see daylight at other
                       Weep holes
                       Flexible HOPE pipes that are known to
                       serve as slope drains
                       Pipes that are clearly connected to roof
                       downspouts via above-ground connections
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                                               Chapter 11: The Outfall Reconnaissance Inventory
       Ductile iron round pipe
 Small diameter (<2") HOPE; Often a
 sump pump (legal), or may be used
  to discharge laundry water (illicit).
  4-6" HOPE; Check if roof leader
        connection (legal)
   Elliptical RCP; Measure both
 horizontal and vertical diameters.
Field connection to inside of culvert;
     Always mark and record.
 Double RCP round pipes; Mark as
 separate outfalls unless known to
   connect immediately up-pipe
   Culvert (can see to other side);
      Don't mark as an outfall
    Open channel "chute" from
commercial parking lot; Very unlikely
  illicit discharge. Mark, but do not
 return to sample (unless there is an
        obvious problem).
Small diameter PVC pipe; Mark, and
   look up-pipe to find the origin.
 CMP outfall; Crews should also note
      upstream sewer crossing.
        Box shaped outfall
  CMP round pipe with two weep
  holes at bridge crossing. (Don't
        mark weep holes)
                        Figure 22: Typical Outfall Types Found in the Field
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Chapter 11: The Outfall Reconnaissance Inventory
Field crews may occasionally encounter an
obvious illicit discharge of sewage or other
pollutants, typified by high turbidity, odors,
floatables and unusual colors. When obvious
discharges are encountered, field crews
should STOP the ORI survey, track down
the source of the discharge and immediately
contact the appropriate water pollution
agency for enforcement. Crews should
photo-document the discharge, estimate its
flow volume and collect a sample for water
quality analysis (if this can be done safely).
All three kinds of evidence are extremely
helpful to support subsequent enforcement.
Chapter 13 provides details on techniques  to
track down individual discharges.

11.4                  1  -

The first section of the ORI field sheet is
used to record basic data about the survey,
including time of day, GPS coordinates for
the outfall, field crew members, and current
                  and past weather conditions (Figure 23).
                  Much of the information in this section is
                  self-explanatory, and is used to create an
                  accurate record of when, where, and under
                  what conditions ORI data were collected.

                  Every outfall should be photographed
                  and marked by directly writing a unique
                  identifying number on each outfall that
                  serves as its subwatershed "address" (Figure
                  24). Crews can use  spray paint or another
                  temporary marker to mark outfalls, but
                  may decide to replace temporary markings
                  with permanent ones if the  ORI is repeated
                  later. Markings help crews confirm outfall
                  locations during future investigations, and
                  gives citizens a better way to report the
                  location of spills or discharges when calling
                  a water pollution hotline. Crews should
                  mark the spatial location of all outfalls they
                  encounter directly on field maps, and record
                  the coordinates with a GPS unit that is
                  accurate to within 10 feet. Crews should take
                  a digital photo of each outfall,  and  record
                  photo numbers in Section 1 of the field sheet.
Section 1; Background Data
Today's date:
Outfall ID:
Time (Military):
Form completed by:
Temperature (ฐF): Rainfall (in.): Last 24 hours: Last 48 hoars:
Latitude: Longitude:
Land Use in Drainage Area (Check all that apply):
O Industrial
D Ultra-Urban Residential
D Subuiban Residential
D Commercial
Photo #s:
Q Open Space
D Institutional
Known Industries:

Notes (e.g., origin of outfall, if known):
                         Figure 23: Section 1 of the ORI Field Sheet
Illicit Discharge Detection and Elimination: A Guidance Manual

       Figure 24: Labeling an outfall
        (a variety of outfall naming
         conventions can be used)
The land use of the drainage area contributing
to the outfall should also be recorded. This
may not always be easy to characterize at
Chapter 11: The Outfall Reconnaissance Inventory

     large diameter outfalls that drain dozens
     or even hundreds of acres (unless you have
     aerial photographs). On the other hand,
     land use can be easily observed at smaller
     diameter outfalls, and in some cases, the
     specific origin can be found (e.g., a roof
     leader or a parking lot; Figure 25). The
     specific origin should be recorded in the
     "notes" portion of Section 1 on the field sheet.

     11.5  ORI Section 2 - Outfall

     This part of the ORI field sheet is where
     basic outfall characteristics are noted
     (Figure 26). These include material, and
     presence of flow  at the outfall, as well as
     the pipe's dimensions (Figure 27). These
     measurements are used to confirm and
     supplement existing storm drain maps (if
     they are available). Many communities only
     map storm drain outfalls that exceed a given
     pipe diameter, and may not contain data on
     the material and condition of the pipe.
          Figure 25: The origin of this corrugated plastic pipe was determined to be a
                           roof leader from the house up the hill.
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Chapter 11: The Outfall Reconnaissance Inventory
Section 2 of the field sheet also asks if the
outfall is submerged in water or obstructed
by sediment and the amount of flow, if
present. Figure 28 provides some photos
that illustrate how to characterize relative
                  submergence, deposition and flow at outfalls.
                  If no flow is observed at the outfall, you can
                  skip the next two sections of the ORI field
                  sheet and continue with Section 5.
Section 2: Outfall Description
D Closed Pipe
Q Open drainage
Flow Present?
Flow Description
(If present)
D Steel
n Other:

D Concrete
D Earthen
D rip-rap
n Other:

D Circular
D Eliptical
d Other:

D Trapezoid
D Parabolic
n Other:

D Single
D Double
D Triple
D Other:


Top Width: 	
Bottom Width:

In Water:
[H Partially
[H Fully
With Sediment:
D Partially
[H Fully

(applicable when collecting samples)
D Yes QNo If No, Sky to Section 5
D Trickle D Moderate D Substantial
                         Figure 26: Section 2 of the ORI Field Sheet
                           Figure 27: Measuring Outfall Diameter
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                                          Chapter 11: The Outfall Reconnaissance Inventory
     Submerged: More than
          below water
 Partially submerged: Bottom is
        below water
Fully submerged: Can't see outfall
                                f- / -
  Outfall fully submerged by debris
Fully submerged from downstream
     trees trapping debris
     Partially submerged by
     leaf debris "back water"
  Trickle Flow: Very narrow stream
            of water
 Moderate Flow: Steady stream,
     but very shallow depth
       Significant flow
(Source is a fire hydrant discharge)
                      Figure 28: Characterizing Submersion and Flow
11.6  ORI Section 3-
Quantitative Characterization
for Flowing Outfalls

This section of the ORI records direct
measurements of flowing outfalls, such as
flow, temperature, pH and ammonia (Figure
29). If desired, additional water quality
                parameters can be added to this section.
                Chapter 12 discusses the range of water
                quality parameters that can be used.

                Field crews measure the rate of flow using
                one of two techniques. The first technique
                simply records the time it takes to fill a
                container of a known volume, such as a one
                liter sample bottle. In the second technique,
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Chapter 11: The Outfall Reconnaissance Inventory
Section 3: Quantitative Characterization
Time to fill
Flow depth
Flow width
Measured length
Time of travel



Ft, In
Ft, In
pH Units

Tape measure
Tape measure
Tape measure
Stop watch
Test strip/Probe
Test strip
                         Figure 29: Section 3 of the ORI Field Sheet
the crew measures the velocity of flow, and
multiplies it by the estimated cross sectional
area of the flow.

To use the flow volume technique, it may be
necessary to use a "homemade" container to
capture  flow, such as a cut out plastic milk
container that is marked to show a one liter
volume. The shape and flexibility of plastic
containers allows  crews to capture relatively
flat and shallow flow (Figure 30). The flow
volume  is determined as the volume of flow
captured in the container per unit time.

The second technique measures flow rate
based on velocity  and cross sectional area,
and is preferred for larger discharges where
containers are too small to effectively
capture  the flow (Figure 31). The crew
measures and marks off a fixed flow length
(usually about five feet), crumbles leaves
or other light material, and drops them into
the discharge (crews can also carry  peanuts
or ping pong balls to use). The crew then
measures the time it takes the marker to
travel across the length. The velocity of
flow is computed as the length of the flow
path (in feet) divided by the travel time (in
seconds). Next, the cross-sectional flow area
is measured by taking multiple readings of
the depth and width of flow. Lastly,  cross-
                  sectional area (in square feet) is multiplied
                  by flow velocity (feet/second) to calculate
                  the flow rate (in cubic feet/second).

                  Crews may also want to measure the quality
                  of the discharge using relatively inexpensive
                  probes and test strips (e.g., water tempera-
                  ture, pH, and ammonia). The choice of
                  which indicator parameters to measure
                  is usually governed by the overall IDDE
                  monitoring framework developed by the
                  community. Some communities have used
                  probes or test strips to measure additional
                  indicators  such as conductivity, chlorine, and
                  hardness. Research by Pitt (for this project)
                  suggests that probes by Horiba for pH
                  and conductivity are the most reliable and
                         Figure 30: Measuring flow (as
                              volume per time)
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                                           Chapter 11: The Outfall Reconnaissance Inventory
accurate, and that test strips have limited

When probes or test strips are used,
measurements should be made from a
sample bottle that contains flow captured
from the outfall. The exact measurement
recorded by the field probe should be
recorded in Section 3  of the field sheet.
Some interpolation may be required for test
strips, but do not interpolate further than the
mid-range between two color points.

11.7  ORI Section 4 - Physical
Indicators for Flowing Outfalls

This section of the ORI field sheet records
data about four sensory indicators associated
with flowing outfalls—odor, color,
turbidity and floatables (Figure 32). Sensory
indicators can be detected by smell or sight,
and require no measurement equipment.
Sensory indicators do not always reliably
predict illicit discharge, since the senses
can be fooled, and may result in a "false
negative" (i.e., sensory indicators fail to
detect an illicit discharge when one is
actually present).  Sensory indicators are
important, however, in detecting the most
severe or obvious discharges. Section 4 of
the field sheet asks whether the sensory
indicator is present, and if so, what is its
severity, on a scale of one to three.
      Step 1: Measure flow depth
      Step 2: Measure flow width
    Step 3: Time the travel of a light
   object (e.g., leaves) along a known
     distance to calculate velocity
   Figure 31: Measuring flow (as
velocity times cross-sectional area)
Section 4: Physical Indicators for Flowing Outfalls Only
Are Any Physical Indicators Present in the flow? D Yes   D No
                                    (If No, Skip to Section 5)
-Does Not Include
D Sewage D Rancid/sour D Petroleum/gas
D Sulfide D Other:
D Clear D Brown D Gray D Yellow
D Green D Orange D Red DOfher:
See severity
D Sewage (Toilet Paper, etc.) D Suds
D Petroleum (oil sheen) D Other
Dl -Faint
Dl- Faint colors in
sample bottle
D 1 - Few/slight; origin
not obvious
D2-Easily detected
sample bottle
D 2 -Cloudy
D 2 - Some; indications
of origin (e.g.,
possible suds or oil
D 3 - Noticeable from a
outfall flow
D 3 - Opaque
D 3 - Some; origin clear
(e.g., obvious oil
sheen, suds, or floating
sanitary materials)
                          Figure 32: Section 4 of the ORI Field Sheet
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Chapter 11: The Outfall Reconnaissance Inventory

Section 4 asks for a description of any
odors that emanate from the outfall and
an associated severity score. Since noses
have different sensitivities, the entire field
crew should reach consensus about whether
an odor is present and how severe it is. A
severity score of one means that the odor
is faint or the crew cannot agree on its
presence or origin. A score of two indicates
a moderate odor within the pipe. A score of
three is assigned if the odor is so strong that
the crew smells it a considerable distance
away from the outfall.
 Make sure the origin of the odor is the
   outfall. Sometimes shrubs, trash or
 carrion, or even the spray paint used to
 mark the outfall can confuse the noses
             of field crews.

The color of the discharge, which can be
clear, slightly tinted, or intense is recorded
next. Color can be quantitatively analyzed
in the lab, but the ORI only asks for a visual
assessment of the discharge color and its
intensity. The best way to measure color is
to collect the discharge in a clear sample
bottle and hold it up to the light (Figure 33).
Field crews should also look for downstream
plumes of color that appear to be associated
with the outfall. Figure 34 illustrates the
spectrum of colors that may be encountered
during an ORI survey, and offers insight on
how to rank the relative intensity or strength
of discharge color. Color often helps identify
industrial discharges; Appendix K provides
guidance on colors often associated with
specific industrial operations.

                  The ORI asks for a visual estimate of
                  the turbidity of the discharge, which is a
                  measure of the cloudiness of the water. Like
                  color, turbidity is best observed in a clear
                  sample bottle, and can be quantitatively
                  measured using field probes. Crews should
                  also look for turbidity in the plunge pool
                  below the outfall, and note any downstream
                  turbidity plumes that appear to be related
                  to the outfall. Field crews can sometimes
                  confuse turbidity with color, which are
                  related but are not the same. Remember,
                  turbidity is a measure of how easily light can
                  penetrate through the sample bottle, whereas
                  color is defined by the tint or intensity of
                  the color observed. Figure 34 provides some
                  examples of how to distinguish turbidity
                  from color, and how to rank its relative
                      Figure 33: Using a sample bottle to
                         estimate color and turbidity
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                                                  Chapter 11: The Outfall Reconnaissance Inventory
      Color: Brown; Severity: 2
        Turbidity Severity: 2
         Sewage Discharge
              Color: 3
            Turbidity: 3
       Color: Red; Severity: 3
       Turbidity Severity: None
        High Turbidity in Pool
        Turbidity Severity: 2
     (Confirm with sample bottle)
Color: Blue-green; Severity: 3
    Turbidity Severity: 2
  Color: White; Severity: 3
        Turbidity: 3
   Failing Septic System:
    Turbidity Severity: 3
            Iron Floe
Color: Reddish Orange; Severity: 3
 (Often associated with a natural
                                        Highly Turbid Discharge
                                       Color: Brown; Severity: 3
                                         Turbidity Severity: 3
                                         Industrial Discharge
                                       Color: Green; Severity: 3
                                         Turbidity Severity: 3
                                    Turbidity in Downstream Plume
                                         Turbidity Severity: 2
                                    (also confirm with sample bottle)
                                         Slight Turbidity
                                           Turbidity: 1
                                (Difficult to interpret this observation;
                                May be natural or an  illicit discharge)
      Construction Site
     Turbidity Severity: 3
                                             Discharge of Rinse
                                             from Floor Sanding
                                             (Found during wet
                                             Turbidity Severity: 3
                             Figure 34: Interpreting Color and Turbidity
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Chapter 11: The Outfall Reconnaissance Inventory


The last sensory indicator is the presence of
any floatable  materials in the discharge or
the plunge pool below. Sewage, oil sheen,
and suds are all examples of floatable
indicators; trash and debris are generally not
in the context of the ORI. The presence of
floatable materials is determined visually,
and some guidelines for ranking their
severity are provided in Figure 35, and
described below.

If you think the floatable is sewage, you
should automatically assign it a severity
score of three since no other source looks
quite like it. Surface oil  sheens are ranked
based on their thickness and coverage. In
some cases, surface sheens may not be
related to  oil  discharges, but instead are
                  created by in-stream processes, such as
                  shown in Figure 36. A thick or swirling
                  sheen associated with a petroleum-like odor
                  may be diagnostic of an oil discharge.

                  Suds are rated based on their foaminess and
                  staying power. A severity score of three is
                  designated for thick foam that travels many
                  feet before breaking up. Suds that break up
                  quickly may simply reflect water turbulence,
                  and do not necessarily have an illicit origin.
                  Indeed, some streams have naturally
                  occurring foams due to the decay of organic
                  matter. On the other hand, suds that are
                  accompanied by a strong organic or sewage-
                  like odor may indicate a sanitary sewer leak
                  or connection. If the suds have a fragrant
                  odor, they may indicate the presence of
                  laundry water or similar wash waters.
          Natural Foam
   Note: Suds only associated with
     high flows at the "drop off"
          Do not record.
       Low Severity Suds
           Rating: 1
 Note: Suds do not appear to travel;
       very thin foam layer
 High severity suds
     Rating: 3
                                       OIL SHEENS
      Low Severity Oil Sheen
            Rating: 1
   Moderate Severity Oil Sheen
           Rating: 2
High Severity Oil Film
     Rating: 3
                      Figure 35: Determining the Severity of Floatables
Illicit Discharge Detection and Elimination: A Guidance Manual

                                          Chapter 11: The Outfall Reconnaissance Inventory
   Figure 36: Synthetic versus Natural Sheen (a) Sheen from bacteria such as iron floe forms a
        sheet-like film that cracks if disturbed (b) Synthetic oil forms a swirling pattern
11.8  ORI Section 5 - Physical
Indicators for Both Flowing and
Non-Flowing Outfalls
Section 5 of the ORI field sheet examines
physical indicators found at both flowing
and non-flowing outfalls that can reveal
the impact of past discharges (Figure
37). Physical indicators include outfall
damage, outfall deposits or stains, abnormal
vegetation growth, poor pool quality, and
benthic growth on pipe surfaces. Common
examples of physical indicators are
portrayed in Figures 38 and 39. Many of
these physical conditions can indicate that
an intermittent or transitory discharge has
occurred in the past, even if the pipe is not
currently flowing. Physical indicators are not
ranked according to their severity, because
they are often subtle, difficult to interpret
and could be caused by other sources. Still,
physical indicators can provide strong clues
about the discharge history of a storm
water outfall, particularly if other discharge
indicators accompany  them.
 Section 5: Physical Indicators for Both Flowing and Non-Flowing Outfalls
 Are physical indicators that are not related to flow present?  Q Yes Q No	(If No, Skip to Section 6)
Outfall Damage
Abnormal Vegetation
Poor pool quality
Pipe benthic growth
CHECK if Present
D Spalling, Cracking or Chipping D Peeling Paint
D Corrosion
DOily D How Line D Paint D Other:
D Excessive D Inhibited
D Odors D Colors D Floatables D Oil Sheen
D Suds D Excessive Algae D Other:
D Brown D Orange D Green D Other:

                         Figure 37: Section 5 of the ORI Field Sheet
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 11: The Outfall Reconnaissance Inventory
    Bacterial growth at this outfall
  indicates nutrient enrichment and a
        likely sewage source.
     Algal mats on lakes indicate
   eutrophication. Several sources
 can cause this problem. Investigate
       potential illicit sources.
   This bright red bacterial growth
 often indicates high manganese and
  iron concentrations. Surprisingly, it
 is not typically associated with illicit
    Illicit discharges or excessive
   nutrient application can lead to
   extreme algal growth on stream
Sporalitis filamentous bacteria, also
 known as "sewage fungus" can be
 used to track down sanitary sewer
    The drainage to this outfall
   most likely has a high nutrient
  concentration. The cause may
 be an illicit discharge, but may be
 excessive use of lawn chemicals.
                          This brownish algae indicates an elevated nutrient level.
                    Figure 38: Interpreting Benthic and Other Biotic Indicators
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                                             Chapter 11: The Outfall Reconnaissance Inventory
    Reddish staining on the rocks
  below this outfall indicate high iron
   Trash is not an indicator of illicit
   discharges, but should be noted.
Toilet paper directly below the storm
          drain outlet.
    Staining at the base of the
  outfall may indicate a persistent,
      intermittent discharge.
     Watershed Protection??
 Excessive vegetation may indicate
  enriched flows associated with
   Brownish stain of unclear origin.
   May be from degradation of the
        brick infrastructure.
Cracked rock below the outfall may
 indicate an intermittent discharge.
Poor pool quality. Consider sampling
 from the pool to determine origin.
             Figure 39: Typical Findings at Both Flowing and Non-Flowing Outfalls
11.9  ORI Sections 6-8 - Initial
Outfall Designation and Actions

The last three sections of the ORI field
sheet are where the crew designates the
illicit discharge severity of the outfall and
recommends appropriate management and
monitoring actions (Figure 40). A discharge
rating is designated as obvious,  suspect,
                  potential or unlikely, depending on the
                  number and severity of discharge indicators
                  checked in preceding sections.

                  It is important to understand that the ORI
                  designation is only an initial determination
                  of discharge potential. A more certain
                  determination as to whether it actually
                  is an illicit discharge is made using a
                  more sophisticated indicator monitoring
                  method. Nevertheless, the ORI outfall
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Chapter 11: The Outfall Reconnaissance Inventory

designation gives program managers a
better understanding of the distribution and
severity of illicit discharge problems within
a sub water shed.

Section 7 of the ORI field sheet records
whether indicator samples were collected
for laboratory analysis, or whether an
intermittent flow trap was installed (e.g.,
an optical brightener trap or caulk dam
described in Chapter 13). Field crews should
record whether the sample was taken from
a pool  or directly from the outfall, and the
type of intermittent flow trap used, if any.
This section can also be used to recommend
follow-up sampling, if the crew does not
carry sample bottles or traps during the

The last section of the ORI field sheet is
used to note any unusual conditions near the
outfall such as dumping, pipe failure, bank
erosion or maintenance needs. While these
maintenance  conditions are not directly
related to illicit discharge detection, they
often are of interest to other agencies and
utilities that maintain infrastructure.

11.10                 the ORI for a

The ORI method is meant to be adaptable,
and should be modified to reflect local
conditions and field experience. Some
                  indicators can be dropped, added or
                  modified in the ORI form. This section looks
                  at four of the most common adaptations to
                  the ORI:

                  ซ  Open Channels

                  ซ  Submerged/Tidally Influenced Outfalls

                  ซ  Cold Climates

                  ซ  Use  of Biological Indicators

                  In each case, it may be desirable to revise
                  the ORI field sheet to collect data reflecting
                  these conditions.

                  Field crews face special challenges in more
                  rural communities that have extensive
                  open channel drainage. The ditches and
                  channels serve as the primary storm water
                  conveyance system, and may lack storm
                  drain and sewer pipes. The open channel
                  network is often very long with only a few
                  obvious outfalls that are located far apart.
                  While the network can have illicit discharges
                  from septic systems, they can typically only
                  be detected in the ORI if a straight pipe is
                  found. Some adaptations for open channel
                  systems are suggested in Table 33.
 Section 6: Overall Outfall Characteruartion
Q] Unlikely n Potential (presence of two or more indicators) C]
Suspect (one or more indicators with a severity of 3) [Z3 Obvious
Section 7: Data Collection
1. Sample for the lab?
2. If yes, collected ftrai:
3. Intermittent flow trap set?
D Yes
[U How
D Yes

If Yes, type: D OBM D Caulk dam
 Section งi Any Non-illicit Discharge Concerns (e.g.$ trash or needed infrastructure repairs}?

                        Figure 40: Sections 6-8 of the ORI Field
Illicit Discharge Detection and Elimination: A Guidance Manual

                                          Chapter 11: The Outfall Reconnaissance Inventory
Submerged/Tidally Influenced

The ORI can be problematic in coastal
communities where outfalls are located
along the waterfront and may be  submerged
at high tide. The ORI methods need to
be significantly changed to address these
constraints. Often, outfalls are initially
located from offshore using canoes or
boats, and then traced landward to the first
manhole that is not tidally influenced. Field
crews then access the storm drain pipe at the
manhole and measure whatever indicators
they can observe in the confined  and  dimly
lit space. Table 33 recommends strategies
to sample outfalls in the challenging
environment of coastal communities.

Winter and Ice

Ice can be used as a discharge indicator
in northern regions when ice forms in
streams and pipes during the winter months
(Figure 41). Because ice lasts for many
weeks, and most illicit discharges are warm,
astute field crews can interpret outfall
history from ice melting patterns along
pipes and streams. For example, exaggerated
melting at a frozen or flowing outfall
may indicate warm water from sewage or
industrial discharge. Be careful, because
groundwater is warm enough to cause some
melting at below freezing temperatures.
Also, ice acts like an intermittent flow trap,
and literally freezes these discharges. Crews
should also look for these traps to find any
discolored ice within the pipe or below the

A final winter indicator is "rime ice," which
forms when steam freezes. This beautiful
ice formation is actually a good indicator of
sewage or other relatively hot discharge that
causes steam to form (Figure 41).

Biological Indicators

The diversity and pollution tolerance of
various species of aquatic life are widely
used as an indicator of overall stream health,
and has sometimes been used to detect illicit
discharges. One notable example is the
presence of the red-eared slider turtle, which
is used in Galveston, Texas to find sewage
discharges, as they have a propensity for the
nutrient rich waters associated with sewage
(Figure 42).
Table 33: Special Considerations for Open Channels/Submerged Outfalls
Too many miles of channel to walk
Difficulty marking them
Interpreting physical indicators
Suggested Modification
Stop walking at a given channel size or drainage area
Mark on concrete or adjacent to earth channel
For open channels with mild physical indicators, progress
the system to investigate further.
Access for ORI - Tidal Influence
Access for ORI - Always submerged
Interpreting physical indicators
Sampling (if necessary)
Suggested Modification
Access during low tide
Access by boat or by shore walking
For outfalls with mild physical indicators, also inspect from the
nearest manhole that is not influenced by tides
Sample "up pipe"
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 11: The Outfall Reconnaissance Inventory
                                                               Figure 42: One biological
                                                               indicator is this red-eared
                                                                     slider turtle
    Figure 41: Cold climate indicators of illicit discharges
11.11  Interpreting ORI Data

The ORI generates a wealth of information
that can provide managers with valuable
insights about their illicit discharge
problems, if the data are managed and
analyzed effectively. The ORI can quickly
define whether problems are clustered
in a particular area or spread across the
community. This section presents a series of
methods to compile, organize and interpret
ORI data, including:

1. Basic Data Management and Quality

2. Outfall Classification

3. Simple Suspect Outfall Counts

4. Mapping ORI Data

5. Subwatershed and Reach Screening

6. Characterizing IDDE Problems at the
   Community Level
                  The level of detail for each analysis method
                  should be calibrated to local resources,
                  program goals, and the actual discharge
                  problems discovered in the stream corridor.
                  In general, the most common conditions and
                  problems will shape your initial monitoring
                  strategy, which prioritizes the subwatersheds
                  or reaches that will  be targeted for more
                  intensive investigations.

                  Program managers  should analyze ORI data
                  well before every stream mile is walked
                  in the community, and use initial results
                  to modify field methods. For example, if
                  initial results reveal widespread potential
                  problems, program  managers may want to
                  add more indicator monitoring to the ORI to
                  track down individual discharge sources (see
                  Chapter 12). Alternatively, if the same kind
                  of discharge problem is repeatedly found,
                  it may be wise to investigate whether there
                  is a common source or activity generating
                  it (e.g., high turbidity observed at many
                  flowing outfalls as a result of equipment
                  washing at active construction sites).
Illicit Discharge Detection and Elimination: A Guidance Manual

                                          Chapter 11: The Outfall Reconnaissance Inventory
Basic Data Management and
Quality Control

The ORI produces an enormous amount of
raw data to characterize outfall conditions.
It is not uncommon to compile dozens
of individual ORI forms in a single
subwatershed. The challenge is to devise a
system to organize, process, and translate
this data into  simpler outputs and formats
that can guide illicit discharge elimination
efforts. The system starts with effective
quality control procedures in the field.

Field sheets should be managed using either
a three-ring binder or a clipboard. A small
field binder offers the ability to quickly flip
back and forth among the outfall forms.
Authorization letters, emergency contact
lists, and extra forms can also be tucked

At the end of each day, field crews should
regroup at a predetermined location to
compare notes. The crew leader should
confirm that all survey reaches and outfalls
of interest have been surveyed, discuss
initial findings, and deal with any logistical
problems. This is also a good time to check
whether field  crews are measuring and
recording outfall data in the same way, and
are consistent in what they are (or are not)
recording. Crew leaders should also use this
time to review field forms for accuracy and
thoroughness. Illegible handwriting should
be neatened and details added to notes and
any sketches.  The crew leader should also
organize the forms together into a single
master binder or folder for future analysis.

Once  crews return from the field, data
should be entered into a spreadsheet or
database. A Microsoft Access database
is provided with this Manual as part of
Appendix D (Figure 43), and is supplied
on a compact disc with each hard copy. It
can also be downloaded with Appendix
D from
Information stored in this database can
easily be imported into a GIS for mapping
purposes. The GIS can generate its own
database table that allows the user to
create subwatershed maps showing outfall
characteristics and problem areas.

Once data entry is complete, be sure to
check the quality of the data. This can be
done quickly by randomly spot-checking
10% of the entered data. For example, if 50
field sheets were completed, check five of
the spreadsheet or database entries. When
transferring data into GIS, quality control
maps that display  labeled problem outfalls
should be created. Each survey crew is
responsible for reviewing the accuracy of
these maps.

Outfall Classification

A simple outfall designation system
has been developed to summarize the
discharge potential for individual ORI field
sheets. Table 34 presents the four outfall
designations that can be made.
Table 34: Outfall Designation System
Using ORI Data
1. Obvious
2. Suspect
3. Potential
4. Unlikely
Outfalls where there is an illicit
discharge that doesn't even
require sample collection for
Flowing outfalls with high
severity on one or more
physical indicators
Flowing or non-flowing outfalls
with presence of two or more
physical indicators
Non-flowing outfalls with no
physical indicators of an illicit
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 11: The Outfall Reconnaissance Inventory
Simple Suspect Outfall Counts

The first priority is to count the frequency of
each outfall designation in the subwatershed
or the community as a whole. This simple
screening analysis counts the number of
problem outfalls per stream mile (i.e.,
the sum of outfalls designated as having
potential, suspected or obvious illicit
discharge potential). The density of problem
outfalls per stream mile is an important
metric to target and screen subwatersheds.

Based on problem outfall  counts, program
managers may discover that a particular
monitoring strategy may not apply to the
community. For example, if few problem
outfalls are found, an extensive follow-up
monitoring program may not be needed,
so that program resources can be shifted
to pollution hotlines to report and control
transitory discharges such as illegal
dumping. The key point of this method is to
avoid getting lost in the raw data, but look
instead to find patterns that can shape a cost-
effective IDDE program.

Mapping ORI Data

Maps are an excellent way to portray
outfall data. If a GIS system is linked to the
ORI database, maps that show the spatial
distribution of problem outfalls, locations
of dumping, and overall reach conditions
can be easily generated. Moreover, GIS
provides flexibility that allows for rapid
updates to maps as new data are collected
and compiled. The sophistication and detail
of maps will depend on the initial findings,
program goals, available software, and GIS

Subwatershed maps are also an effective and
important communication and education tool
to engage stakeholders (e.g., public officials,
businesses and community residents), as
                 they can visually depict reach quality and
                 the location of problem outfalls. The key
                 point to remember is that maps are tools
                 for understanding data. Try to map with
                 a purpose in mind. A large number of
                 cluttered maps may only confuse, while
                 a smaller number with select data may
                 stimulate ideas for the follow-up monitoring

                 Subwatershed and Survey Reach

                 Problem outfall metrics are particularly
                 valuable to screen or rank priority
                 subwatersheds or survey reaches. The
                 basic approach is simple: select the outfall
                 metrics that are most important to IDDE
                 program goals, and then see how individual
                 subwatersheds or reaches rank in the
                 process. This screening process can help
                 determine which subwatersheds will be
                 priorities for initial follow-up monitoring
                 efforts. When feasible, the screening process
                 should incorporate non-ORI data, such as
                 existing dry weather water quality data,
                 citizen complaints, permitted facilities, and
                 habitat or biological stream indicators.
                                Detection and Elimination
                      Figure 43: Sample screen from ORI
                          Microsoft Access database
Illicit Discharge Detection and Elimination: A Guidance Manual

                                           Chapter 11: The Outfall Reconnaissance Inventory
An example of how outfall metrics can
screen subwatersheds is provided in
Table 35. In this hypothetical example,
four metrics were used to screen three
subwatersheds within a community:
number of suspect discharges, subwatershed
population as a percent of the total
community, number of industrial discharge
permits, and number of outfalls per stream
mile. Given these screening criteria,
subwatershed C was selected for the next
phase of detailed investigation.

Characterizing the IDDE Problem
at the Community Level

ORI data should be used to continuously
revisit and revise the IDDE program as
more is learned about the nature and
                                distribution of illicit discharge problems in
                                the community. For example, ORI discharge
                                designation should be compared against
                                illicit discharge potential (IDP) predictions
                                made during the original desktop analysis
                                (Chapter 5) to refine discharge screening
                                factors, and formulate new monitoring

                                In general, community illicit discharge
                                problem can be characterized as
                                minimal, clustered, or severe (Table 36).
                                In the minimal scenario, very few and
                                scattered problems exist; in the clustered
                                scenario, problems are located in isolated
                                subwatersheds; and in the severe scenario,
                                problems are widespread.
Table 35: An Example of ORI Data Being Used to Compare Across Subwatersheds

Subwatershed A
Subwatershed B
Subwatershed C
# of suspect
as % of total
# of industrial
# of outfalls per stream/
conveyance mile
              Table 36: Using Stream and ORI Data to Categorize IDDE Problems
                            ORI Support Data
• Less than 10% of total outfalls are flowing
• Less than 20% of total outfalls with obvious, suspect or potential designation
• Two thirds of the flowing outfalls are located within one third of the subwatersheds
• More than 20% of the communities subwatersheds have greater than 20% of outfalls
  with obvious, suspect or potential designation
• More than 10% of total outfalls are flowing
• More than 50% of total outfalls with obvious, suspect or potential designation
• More than 20% of total outfalls with obvious or suspect designation
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 11: The Outfall Reconnaissance Inventory
11.12 Budgeting and Scoping
the ORI

Many different factors come into play when
budgeting and scoping an ORI survey:
equipment needs, crew size and the stream
miles that must be covered. This section
presents some simple rules of thumb for ORI

Equipment costs for the ORI are relatively
minor, with basic equipment to outfit one
team of three people totaling about $800
(Table 37). This cost includes one-time
expenses to acquire waders, a digital camera
and a GPS unit, as well as disposable
                 The majority of the budget for an ORI is for
                 staffing the desktop analysis, field crews and
                 data analysis. Field crews can consist of two
                 or three members, and cover about two to
                 three miles of stream (or open channel) per
                 day. Three staff-days should be allocated for
                 pre- and post-field work for each day spent
                 in the field.

                 Table 38 presents example costs for two
                 hypothetical communities that conduct the
                 ORI. Community A has 10 miles of open
                 channel to investigate, while Community
                 B has 20 miles. In addition, Community
                 A has fewer staff resources  available and
                 therefore uses two-person field crews, while
                 Community B uses three-person field crews.
                 Total costs are presented as annual costs,
                 assuming that each community is able to
                 conduct the ORI for all miles in one year.
Table 37: Typical Field Equipment Costs for the ORI
100 Latex Disposable Gloves
5 Wide Mouth Sample Bottles (1 Liter)
Large Cooler
3 Pairs of Waders
Digital Camera
20 Cans of Spray Paint
Test Kits or Probes
1 GPS Unit
1 Measuring Tape
1 First Aid Kit
Flashlights, Batteries, Labeling tape, Clipboards
Illicit Discharge Detection and Elimination: A Guidance Manual

                                        Chapter 11: The Outfall Reconnaissance Inventory
Table 38: Example ORI Costs
Field Equipment1
Staff Field Time2
Staff Office Time3
Community A
Community B
1 From Table 44
2 Assumes $25/hour salary (2 person teams in Community A and three- person teams in
Community B) and two miles of stream per day.
3 Assumes three staff days for each day in field.
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 11: The Outfall Reconnaissance Inventory
118                          Illicit Discharge Detection and Elimination: A Guidance Manual

                                                         Chapter 12: Indicator Monitoring
Indicator monitoring is used to confirm
illicit discharges, and provide clues about
their source or origin. In addition, indicator
monitoring can measure improvements
in water quality during dry weather flow
as a result of the local IDDE program.
This chapter reviews the suite of chemical
indicator parameters that can identify
illicit discharges, and provides guidance on
how to collect, analyze and interpret each

Program managers have a wide range of
indicator parameters and analytical methods
to choose from when determining the
presence and source of illicit discharges. The
exact combination of indicator parameters
and methods selected for a community is
often unique. This chapter recommends
some general approaches for communities
that are just starting an indicator monitoring
program or are looking for simple, cost-
effective, and safe alternatives to their
current program.

                 of the

This chapter provides technical support
to implement the basic IDDE monitoring
framework shown in Figure 44, and is
organized into eight sections as follows:

1.  Review of indicator parameters

2.  Sample collection considerations

3.  Methods to analyze samples

4.  Methods to distinguish flow types

5.  Chemical library

6.  Special monitoring methods for
   intermittent and transitory discharges

7.  Iti-stream dry weather monitoring

8.  Costs for indicator monitoring

„ Non - / . j OBM 1
" FlowinqV / ' 	 • — '
'- 	 interminera^-|Cau|kDam i
| Off Hours |— |
	 Flowchart p^^.^
Monitoring — *• nps 	 s^FhwingtT T

Denotes a monitoring
•N__ mausinai ^^~
ป0b--iou" ^FindandFix
nical 	 Mass
ary Balance
i Model

                          Figure 44: IDDE Monitoring Framework
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 12: Indicator Monitoring

Program managers developing an
indicator monitoring program need a solid
background in basic water chemistry, and
field and laboratory methods. This chapter
describes the major factors to consider when
designing an indicator monitoring program
for illicit discharges, and assumes some
familiarity with water quality sampling and
analysis protocols.

Indicator monitoring terminology can be
confusing, so some of the basic terms are
defined as they specifically relate to illicit
discharge control. Some of the common
terms introduced in this Chapter are defined

Chemical Library: A database and statistical
summary of the chemical characteristics, or
"fingerprint" of various discharge flow types
in a community (e.g., sewage, wash water,
shallow groundwater, tap water, irrigation
water, and liquid wastes). The library is
assembled by collecting and analyzing
representative  samples from the source of
each major flow type in the community.

Chemical Mass Balance Model (CMBM):
A computer model that uses flow
characteristics from a chemical library file
of flow types to estimate the most likely
source components that contribute to dry
weather flows.

Detergents: Commercial or retail products
used to wash clothing. Presence of
detergents in flow is usually measured as
surfactants or fluorescence.

False Negative: An indicator sample that
identifies a discharge as uncontaminated
when it actually is contaminated.

False Positive: An indicator sample that
identifies a discharge as contaminated when
it is not.
                  Flow Chart Method: The use of four
                  indicators (surfactants, ammonia, potassium,
                  and fluoride) to identify illicit discharges.

                  Indicator Parameter: A water quality
                  measurement that can be used to identify a
                  specific discharge flow type, or discriminate
                  between different flow types.

                  Monitoring: A strategy of sample collection
                  and laboratory analysis to detect and
                  characterize illicit discharges.

                  Optical Brightener Monitoring (OEM)
                  Traps: Traps that use absorbent pads to
                  capture dry weather flows, which can
                  later be observed under a fluorescent light
                  to determine if detergents using optical
                  brighteners were present.

                  Reagent: A chemical added to a sample
                  to create a reaction that enables the
                  measurement of a target chemical parameter.

                  Sampling: Water sample collection from
                  an outfall, pipe or stream, along with
                  techniques to store and preserve them for
                  subsequent laboratory analysis.

                  Surfactants: The main component of
                  commercial detergents that detaches dirt
                  from the clothing. The actual concentration
                  of surfactants is  much lower than the
                  concentration of detergent, but analytical
                  methods that measure surfactants are
                  often referred to as "detergents." To avoid
                  confusion, this chapter expresses the
                  concentration of surfactants as "detergents
                  as surfactants."
Illicit Discharge Detect/on and Elimination: A Guidance Manual

12.1                              to

At least fifteen different indicator parameters
can confirm the presence or origin of an illicit
discharge. These parameters are discussed in
detail in Appendix F and include:

   •   Ammonia
   •   Boron
   ซ   Chlorine
   •   Color
   *   Conductivity
   •   Detergents
   •   E. coll, enterococi, and total coliform
   •   Fluorescence
   ซ   Fluoride
   ซ   Hardness
   ซ   pH
   •   Potassium
   •   Surface Tension
   •   Surfactants
   *   Turbidity

In most cases, however, only a small subset
of indicator parameters (e.g., three to five) is
required to adequately characterize an illicit
discharge. This section summarizes the
different indicator parameters that have been

An ideal indicator parameter should reliably
distinguish illicit discharges from clean
water and provide clues about its sources.
In addition, they should have the following

•  Have a significantly different concentra-
   tion for major flow or discharge types
           Chapter 12: Indicator Monitoring

*  Exhibit relatively small variations in
   concentrations within the same flow or
   discharge type

*  Be conservative (i.e., concentration will
   not change over time due to physical,
   chemical or biological processes)

ป  Be easily measured with acceptable
   detection limits, accuracy, safety and

No single indicator parameter is perfect,
and each community must choose the
combination of indicators that works best for
their local conditions and discharge types.
Table 39 summarizes the parameters that
meet most of the indicator criteria, compares
their ability to detect different flow types,
and reviews some of the challenges that may
be encountered when measuring them. More
details on indicator parameters are provided
in Appendix F.

Data in Table 39 are based on research by
Pitt (Appendix E) conducted in Alabama,
and therefore, the percentages shown to
distinguish "hits" for specific flow types
should be viewed as representative and
may shift for each community. Also, in
some  instances, indicator parameters were
"downgraded" to account for regional
variation or dilution effects. For example,
both color and turbidity are excellent
indicators of sewage based on discharge
fingerprint data, but both can vary regionally
depending on the composition of clean
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 12: Indicator Monitoring
Table 39: Indicator Parameters Used to Detect Illicit Discharges
Detergents -
ฃ. co//
Total Coliform
Discharge Types It Can Detect
Industrial or
Liquid Wastes

Laboratory/Analytical Challenges
Can change into other nitrogen forms
as the flow travels to the outfall

High chlorine demand in natural
waters limits utility to flows with very
high chlorine concentrations

Ineffective in saline waters
Reagent is a hazardous waste
24-hour wait for results
Need to modify standard monitoring
protocols to measure high bacteria
Reagent is a hazardous waste
Exception for communities that do not
fluoridate their tap water

May need to use two separate
analytical techniques, depending on
the concentration

• Can almost always (>80% of samples) distinguish this discharge from clean flow types (e.g., tap water or natural water). For
tap water, can distinguish from natural water.
ฎ Can sometimes (>50% of samples) distinguish this discharge from clean flow types depending on regional characteristics,
or can be helpful in combination with another parameter
O Poor indicator. Cannot reliably detect illicit discharges, or cannot detect tap water
N/A: Data are not available to assess the utility of this parameter for this purpose.
Data sources: Pitt (this study)
'Fluoride is a poor indicator when used as a single parameter, but when combined with additional parameters (such as
detergents, ammonia and potassium), it can almost always distinguish between sewage and washwater.
12.2 Sample Collection

Sample collection is an important aspect of
an IDDE program. Program managers need
to be well informed about the key facets of
sampling such as sample handling, QA/QC,
and safety. The guidance in this section is
limited to an overview of sample collection
considerations including: equipment needed
                 for collecting samples, elements of sampling
                 protocols, and general tips. Several useful
                 documents are available that detail accepted
                 water quality sampling protocols such as the

                 •  Burton and Pitt (2002) - Stormwater
                    Effects Handbook: A Toolbox for
                    Watershed Managers, Scientists, and
Illicit Discharge Detection and Elimination: A Guidance Manual

                                                         Chapter 12: Indicator Monitoring
•  USGS National Field Manual for the
   Collection of Water-Quality Data

•  Standard Methods for the Examination
   of Water and Wastewater

•  EPA NPDES Stormwater Sampling
   Guidance Document (Note: while
   this document is oriented towards wet
   weather sampling, there are still many
   sampling procedures that apply to dry
   weather sampling)

State environmental agencies are also a good
resource to contact for recommended or
required sampling protocols.

Equipment Needed for Field

The basic equipment needed to collect
samples is presented in Table 40. Most
sampling equipment is easily available for
purchase from scientific supply companies
and various retail stores.

Developing a  Consistent Sample
Collection Protocol

Samples should never be collected
haphazardly. To get reliable, accurate, and
defensible data, it is important to develop a
consistent field sampling protocol to collect
each indicator sample. A good field sampling
protocol incorporates eight basic elements:
1.  Where to collect samples
2.  When to collect samples
3.  Sample bottle preparation
4.  Sample collection technique
5.  Storage and preservation of samples
6.  Sample labeling and chain of custody
7.  Quality assurance/control samples
8.  Safety considerations

Appendix G provides more detail on each
monitoring element. Some communities
already have established sampling protocols
that are used for in-stream or wet weather
sampling. In most cases these existing
sampling protocols are sufficient to conduct
illicit discharge sampling.

Tips for Collecting Illicit Discharge

The following tips can improve the quality
of your indicator monitoring program.

1.  Remember to fill out an ORI field form
   at every outfall where samples are
   collected. The ORI form documents
   sample conditions, outfall characteristics
   and greatly aids in interpreting indicator
   monitoring data.

2.  Most state water quality agencies have
   detailed guidance on sampling protocols.
   These resources should be consulted
   and the appropriate guidelines followed.
   Another useful guidance on developing a
   quality assurance plan is the "Volunteer
   Monitor's Guide to Quality Assurance
   Project Plans" (EPA, 1996).
  Table 40: Equipment Needed for Sample
• A cooler (to be kept in the vehicle)
• Ice or "blue ice" (to be kept in the vehicle)
• Permanent marker (for labeling the samples)
• Labeling tape or pre-printed labels
• Several dozen one-liter polyethylene plastic
  sample bottles
• A "dipper," a measuring cup at the end of a
  long pole, to collect samples from outfalls that
  are hard to reach
• Bacteria analysis sample bottles (if applic-
  able), typically pre-cleaned 120ml_ sample
  bottles, to ensure against contamination
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 12: Indicator Monitoring
3.   Sample in batches where feasible to cut
    down on field and mobilization time.

4.   Avoid sampling lagged storm water
    flows by sampling at least 48 to 72 hours
    after runoff producing events.

5.   It may be necessary to collect multiple
    samples at a single outfall if preservatives
    are going to be  used. Preservatives are
    typically necessary when long hold
    times are required for samples before
    analysis occurs. Appendix G contains
    guidance on the required preservation
    and maximum allowable hold times for
    various parameters.


This section reviews methods to analyze
indicator samples, and begins with a
discussion of whether they should be
analyzed in-house or sent to an independent
contract lab. Next, recommended methods
for analyzing indicator parameters
are outlined, along  with data on their
comparative cost, safety, and accuracy.
Lastly, tips are offered to improve an
indicator monitoring program.


Program managers need to decide whether
to  analyze samples in-house, or through an
independent monitoring laboratory. The
decision on which route to take is often
based on the answers to the following

•   What level of precision or accuracy is
    needed for the indicator parameter (sj?
    Precise and accurate data are needed
    when indicator  monitoring is used
    to legally document a violation or
                     enforcement action. The lab setting is
                     important, since the quality of the data
                     may be challenged. Precise data are
                     also needed for outfalls that have very
                     large drainage areas. These discharges
                     are often diluted by groundwater, so
                     lab methods must be sensitive and have
                     low detection limits to isolate illicit
                     discharges that are masked or blended
                     with other flow types. Accurate data
                     are also needed for large outfalls since
                     the cost and effort triggered by a false
                     positive reading to track and isolate
                     discharges in a large and complex
                     drainage area is much greater.

                     How quickly are sampling results
                     needed? Fast results are essential if the
                     community wants to respond instantly
                     to problem outfalls. In this case, the
                     capability to collect and analyze
                     indicator samples in-house is desirable to
                     provide quick response.

                     .How much staff time and training is
                     needed to support in-house analysis?
                     Local staff that perform lab analysis
                     must be certified in laboratory safety,
                     quality control and proper analytical
                     procedures. Communities that do not
                     expect to collect many indicator samples
                     may want to utilize a contract lab to
                     reduce staff training costs.

                     Does a safe environment exist to
                     analyze samples and dispose of wastes?
                     A safe environment is needed for lab
                     analysis including storage in a fireproof
                     environment, eyewash stations, safety
                     showers, fume hoods and ventilation.
                     Lab workers should have standard
                     safety equipment  such as gloves, safety
                     glasses and lab coats. Lastly, many of the
                     recommended analytical methods create
                     small quantities of hazardous wastes that
                     need to be properly disposed. Program
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                                                           Chapter 12: Indicator Monitoring
   managers should carefully evaluate in-
   house work space to determine if a safe
   lab environment can be created.

•  What is the comparative cost for sample
   analysis in each option? The initial
   up-front costs to use an independent
   laboratory are normally lower than
   those required to establish an in-house
   analysis capability. An in-house analysis
   capability normally becomes cost-
   effective when a community expects to
   analyze more than 100 indicator  samples
   per year. Section 12.8 outlines some
   of the key budget factors to consider
   when making this decision, but program
   managers should always get bids from
   reputable and certified contract labs to
   determine  analysis costs.

•  Are existing monitoring laboratories
   available in the community? Cost
   savings are often realized if an existing
   wastewater treatment or drinking water
   lab can handle the sample analysis.
   These labs normally possess the
   equipment, instruments and trained staff
   to perform the water quality analyses for
   indicator parameters.

Considerations for In-house
Analysis Capability

Three basic settings can be used to analyze
indicator parameters in-house: direct field
measurements, small office lab, and a more
formal municipal lab. The choice of which
in-house setting to use depends on the
indicator parameters selected, the need for
fast and accurate results and safety/disposal

In-Field Analysis - A few indicator
parameters can be analyzed in the field with
probes and other test equipment (Figure 45).
While most field parameters can identify
problem outfalls, they generally cannot
distinguish the specific type of discharge.
Some of the situations where in-field
analysis10 is best applied are:

•  When a community elects to use one
   or two indicator parameters, such as
   ammonia and potassium, that can be
   measured fairly easily in the field

•  When field crews measure indicator
   parameters to trace or isolate a
   discharge in a large storm drain pipe
   network, and need quick results to
   decide where to go next

Office Analysis - Many of the recommended
indicator parameters can be analyzed in
an informal "office" lab with the possible
exception of surfactants and fluoride (Figure
46). The office analysis option makes sense
in communities that have available and
trained staff, and choose analytical methods
that are safe and have few hazardous waste
disposal issues.  Another option is to use the
office lab to conduct most indicator analyses,
but send out fluoride and surfactant indicator
samples to  a contract lab.
   The methodology for any bacteria
   analysis also has a waste disposal
   issue (e.g., biohazard). Check state
   guidance for appropriate disposal
10 Some communities have had success with in-field
analysis; however, it can be a challenging environment to
conduct rapid and controlled chemical analysis. Therefore,
it is generally recommended that the majority of analyses
be conducted in a more controlled "lab" setting.
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Chapter 12: Indicator Monitoring
Formal Laboratory Setting - The ideal
option in many communities is to use an
existing municipal or university laboratory.
Existing labs normally have systems in
place to dispose of hazardous material, have
room and facilities for storing samples, and
are equipped with worker safety features.
Be careful to craft a schedule that does not
interfere with other lab activities.

When in-house analysis is used, program
managers need to understand the basic
analytical options, safety considerations,
equipment needs and analysis costs for each
analytical method used to measure indicator
parameters. This understanding helps
program managers choose what indicator
parameters to collect and where they should
be analyzed. Much of this information is
                  detailed in Appendix F and summarized

                  Supplies and Equipment
                  The basic supplies needed to perform lab
                  analysis are described in Table 41, and are
                  available from several scientific equipment
                  suppliers. In addition, reagents, disposable
                  supplies and some specialized instruments
                  may be needed, depending on the specific
                  indicator parameters analyzed. For a partial
                  list of suppliers, consult the Volunteer
                  Stream Monitoring Manual (US EPA,
                  1997), which can be accessed at www.epa.
                  appendb.html.  Table 42 summarizes the
                  equipment needed for each analytical
    Figure 45: Analyzing samples in the
             back of a truck
                         Figure 46: Office/lab set up in
                                Fort Worth, TX
                               Table 41: Basic Lab Supplies
               Disposable Supplies
        Deionized water (start with about 10
        gallons, unless a reverse osmosis machine
        is available)
        Nitric acid for acid wash (one or two gallons
        to start)
        Lab or surgical gloves
        Lab coats
        Safety glasses
                 About two dozen each of 100 and 200 mL
                 Two or three 100 mL graduated cylinders
                 Two or three tweezers
                 Pipettes to transfer samples in small
Illicit Discharge Detection and Elimination: A Guidance Manual

                                                         Chapter 12: Indicator Monitoring
Table 42: Analytical Methods Supplies Needed
Detergents -
Surfactants (MBAS)
E. Co//
or Colorimeter
or Colorimeter
or Colorimeter
Horiba probe
Black Light
or Colorimeter
Burette and Stand
Digital Titrator
Horiba Probe
Horiba Probe
or Colorimeter
Reagents or Kits
Hach reagents for
method 8155
Hach reagents for
method 10061
Hach reagents for
method 8021
Color Kit
Chemets Detergents
Colilert Reagent
Quanti-Tray Sheets
Hach reagents for
method 8029
EDTA Cartridges or
and Buffer Solution
Hach Reagents for
method 801 2
Unique Suppliers
I DEXX Corporation
Table 43 compares the per sample cost to
analyze indicator parameters. In general,
the per sample cost is fairly similar for
most parameters, with the exception of
bacteria analyses for E. coli, total coliform,
or Enterococci. Reagents typically cost
less than $2.00 per sample, and equipment
purchases seldom exceed $1,000. The typical
analysis time averages less than 10 minutes
per sample. More information on budgeting
indicator monitoring programs can be found
in Section 12.8.
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Chapter 12: Indicator Monitoring
Table 43: Chemical Analysis Costs
- Surfactants1
ฃ. Co// or
Total Coliform1
(High Range)
(Low Range)
Analysis Cost
Per Sample Costs
(24 hour
waiting time)
Staff Cost
Total Cost
Per Sample
Initial Equipment Cost
(Sealer and Incubator)
(Digital Titrator)
1 Potentially high waste disposal cost for these parameters.
2 The disposable supplies estimates are based on the use of standards to calibrate a probe or meter.
3 Analysts can achieve significant economies of scale by analyzing these parameters in batches.
4 Represents the cost of a colorimeter. The price of a spectrophotometer, which measures a wider range of parameters, is
more than $2,500. This one-time cost can be shared among chlorine, fluoride, boron, potassium and ammonia.
Additional Tips for In-house
Laboratory Analysis
The following tips can help program
managers with in-house laboratory analysis

•  Program managers may want to use
   both in-house analysis and contract labs
                    to measure the full range of indicator
                    parameters needed in a safe and cost-
                    effective manner. In this case, a split
                    sample analysis strategy is used, where
                    some samples are sent to the contract
                    lab, while others are analyzed in house.
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                                                         Chapter 12: Indicator Monitoring
•  Remember to order enough basic lab
   supplies, because they are relatively
   cheap and having to constantly re-
   order supplies and wash glassware
   can be time-consuming. In addition,
   some scientific supply companies have
   minimum order amounts, below which
   additional shipping and handling is

•  Be careful to craft a sample analysis
   schedule that doesn't interfere with
   other lab operations, particularly if it
   is a municipal lab. With appropriate
   preservation, many samples can be
   stored  for several weeks.

Considerations for Choosing a
Contract Lab

When a community elects to send samples
to an independent contract lab  for analysis, it
should investigate seven key factors:

1. Make sure that the lab is EPA-certified
   for the indicator parameters you
   choose. A state-by-state list of EPA
   certified labs for drinking water can
   be found at:
   safewater/privatewells/labs.html. State
   environmental agencies are also good
   resources to contact for pre-approved

2. Choose a lab with a short turn-around
   time. Some Phase I communities had
   problems administering their programs
   because of long turn-around times from
   local labs (CWP, 2002). As a rule,  a lab
   should be able to produce results within
   48 hours.

3. Clearly specify the indicator parameter
   and analysis method you want, using the
   guidance in this manual or advice from a
   water quality expert.
4.  Ensure that the maximum hold time for
   each indicator parameter exceeds the
   time it takes to ship samples to the lab
   for analysis.

5.  Carefully review and understand the
   shipping and preservation instructions
   provided by the contract lab.

6.  Look for labs that offer electronic report-
   ing of sample results, which can greatly
   increase turn-around time, make data
   analysis easier, and improve response

7.  Periodically check the lab's QA/QC
   procedures, which should include lab
   spikes, lab blanks, and split samples. The
   procedures for cleaning equipment and
   calibrating instruments should also be
   evaluated. These QA/QC procedures are
   described below.

   •  Lab spikes - Samples of known
       concentration are prepared in the
       laboratory to determine the accuracy
       of instrument readings.

   •  Lab blanks - Deionized water samples
       that have a known zero concentration
       are used to test methods, or in some
       methods to "zero" the instruments.

   •  Split samples - Samples are divided
       into two separate samples  at  the
       laboratory for a comparative  analysis.
       Any difference between the two
       sample results suggests the analysis
       method may not be repeatable.

   •  Equipment cleaning and instrument
       maintenance protocols - Each lab
       should have specific and routine
       procedures to maintain equipment
       and clean glassware and tubing.
       These procedures should be clearly
       labeled on each piece of equipment.
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Chapter 12: Indicator Monitoring
   •  Instrument calibration - Depending
      on the method, instruments may
      come with a standard calibration
      curve, or may require calibration
      at each use. Lab analysts should
      periodically test the default
      calibration curve.

Table 44 summarizes estimated costs associ-
ated with sample analyses at a contract lab.

12.4 Techniques to Interpret
Indicator Data

Program managers need to decide on the
best combination of indicator parameters
that will be used to confirm discharges and
identify flow types. This section presents
guidance  on four techniques to interpret
indicator parameter data:

•  Flow Chart Method (recommended)

•  Single Parameter Screening

•  Industrial Flow Benchmarks

•  Chemical Mass Balance Model (CMBM)
Table 44: Typical Per Sample Contract
Lab Costs
Detergents - Surfactants
Enterococci, ฃ. Co/; or Total
$12 -$25
$16 -$20
$6 -$10
$7 -$11
$2- $6
$17- $35
$17 -$35
$14 -$25
$8 -$16
$2- $7
$12 -$14
$9 -$12
                 All four techniques rely on benchmark
                 concentrations for indicator parameters in
                 order to distinguish among different flow
                 types. Program managers are encouraged
                 to adapt each technique based on local
                 discharge concentration data, and some
                 simple statistical methods for doing so are
                 provided throughout the section.

                 The Flow Chart Method

                 The Flow Chart Method is recommended
                 for most Phase II communities, and was
                 originally developed by Pitt et al. (1993)
                 and Lalor (1994) and subsequently updated
                 based on new research by Pitt during
                 this project. The Flow Chart Method can
                 distinguish four major discharge types found
                 in residential watersheds, including sewage
                 and wash water flows  that are normally the
                 most common illicit discharges. Much of the
                 data supporting the method were collected
                 in Alabama and other regions, and some
                 local adjustment may be needed in some
                 communities. The Flow Chart Method is
                 recommended because it is a relatively
                 simple technique that  analyzes four or
                 five indicator parameters that are safe,
                 reliable and inexpensive to measure. The
                 basic decision points involved in the Flow
                 Chart Method are shown in Figure 47  and
                 described below:

                 Step 1: Separate clean flows from
                 contaminated flows using detergents
                 The first step evaluates whether the
                 discharge is derived from sewage or
                 washwater sources, based on the presence
                 of detergents. Boron and/or surfactants are
                 used as the primary detergent indicator, and
                 values of boron or surfactants that exceed
                 0.35 mg/L and 0.25 mg/L, respectively,
                 signal that the discharge is contaminated by
                 sewage or washwater.
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                                                         Chapter 12: Indicator Monitoring
         f  START  I
 or Boron
         Figure 47: Flow Chart to Identify Illicit Discharges in Residential Watersheds
Step 2: Separate washwater from
wastewafer using the Ammonia/
Potassium ratio
If the discharge contains detergents, the
next step is to determine whether they
are derived from sewage or washwater,
using the ammonia to potassium ratios.
A ratio greater than one suggests sewage
contamination, whereas ratios less than
one indicate washwater contamination. The
benchmark ratio was developed by Pitt et al.
(1993) and Lalor (1994) based on testing in
urban Alabama watersheds.
                 Step 3: Separate tap water from
                 natural water
                 If the sample is free of detergents, the next
                 step is to determine if the flow is derived
                 from spring/groundwater or comes from
                 tap water. The benchmark indicator used
                 in this step is fluoride, with concentrations
                 exceeding 0.60 mg/L indicating that potable
                 water is the source. Fluoride levels between
                 0.13 and 0.6 may indicate non-target
                 irrigation water. The purpose of determining
                 the source of a relatively "clean discharge" is
                 that it can point to water line breaks,  outdoor
                 washing, non-target irrigation and other uses
                 of municipal water that generate flows with
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 12: Indicator Monitoring
Adapting the Flow Chart Method
The Flow Chart Method is a robust tool for
identifying illicit discharge types, but may
need to be locally adapted, since much of the
supporting data was collected in one region
of the country. Program managers should
look at four potential modifications to the
flow chart in their community.

1) Is boron or surfactants a superior local
   indicator of detergents?

Surfactants are almost always a more
reliable indicator of detergents, except for
rare cases where groundwater has been
contaminated by sewage. The disadvantage
of surfactants is that the recommended
analytical method uses a hazardous chemical
as the reagent. Boron uses a safer analytical
method. However, if boron is used as a
detergent indicator, program managers
should sample boron levels in groundwater
and tap water, since they can vary regionally.
Also, not all detergent formulations
incorporate boron at high levels, so it may
not always be a strong indicator.

2) Is the ammonia/potassium ratio of
   one the best benchmark to distinguish
   sewage from washwater?

The ammonia/potassium ratio is a good
way to distinguish sewage from washwater,
although the exact ratio appears to vary
in different regions of the  country. The
benchmark value for the ratio was derived
from extensive testing in one Alabama city.
In fact, data collected in another Alabama
city indicated an ammonia/potassium ratio
of 0.6 distinguished sewage from wash
water. Clearly, program managers should
evaluate the ratio in their own community,
although the proposed ratio of 1.0 should
still capture the majority of sewage
discharges. The ratio can be refined over
                 time using indicator monitoring at local
                 outfalls, or through water quality sampling
                 of sewage and washwater flow types for the
                 chemical library.

                 3)  Is fluoride a good indicator of tap water?

                 Usually. The two exceptions are
                 communities that do not fluoridate their
                 drinking water or have elevated fluoride
                 concentrations in groundwater. In both
                 cases, alternative indicator parameters such
                 as hardness  or chlorine may be preferable.

                 4)  Can the  flow chart be expanded?

                 The flow chart presented in Figure 47 is
                 actually a simplified version of a more
                 complex flow chart developed by Pitt for this
                 project, which is presented in Appendix H.
                 An expanded flow  chart can provide more
                 consistent and detailed identification of flow
                 types, but obviously requires more analytical
                 work and data analysis. Section 12.5
                 provides guidance  on statistical techniques
                 to customize the flow chart method based on
                 your local discharge data.

                 Research by Lalor  (1994) suggests that
                 detergents is the best single parameter
                 to detect the presence or absence  of the
                 most common illicit discharges (sewage
                 and washwater). The recommended
                 analytical method for detergents uses a
                 hazardous reagent, so the analysis needs
                 to be conducted in  a controlled laboratory
                 setting with proper safety equipment. This
                 may limit the flexibility of a community if
                 it is conducting analyses in the field or in a
                 simple office lab.

                 Ammonia is another single parameter
                 indicator that has been used by some
                 communities with widespread or  severe
Illicit Discharge Detection and Elimination: A Guidance Manual

                                                           Chapter 12: Indicator Monitoring
sewage contamination. An ammonia
concentration greater than 1 rag/L is
generally considered to be a positive
indicator of sewage contamination.
Ammonia can be analyzed in the field
using a portable spectrophotometer, which
allows for fairly rapid results and the ability
to immediately track down sources and
improper connections (see Chapter 13 for
details on tracking down illicit discharges)11.
Since ammonia can be measured in the field,
crews can get fast results and immediately
proceed to track down the source of the
discharge using pipe testing methods (see
Chapter 13 for details).

As a single parameter, ammonia has some
limitations. First, ammonia by itself may
not always be capable of identifying sewage
discharges, particularly if they are diluted
by "clean" flows. Second, while some
washwaters and industrial discharges have
relatively high ammonia concentrations,
not all do, which increases the prospects of
false negatives. Lastly, other dry weather
discharges, such as non-target irrigation,
can also have high ammonia concentrations
that can occasionally exceed 1 mg/L.
Supplementing ammonia with potassium
and looking at the ammonia/potassium
ratio is a simple adjustment to the single
parameter approach that helps to further and
more accurately characterize the discharge.
Ratios greater than one indicate a sewage
source, while ratios less than or equal to
one indicate a washwater source.  Potassium
is easily analyzed using a probe (Horiba
Cardy™ is the recommended probe).
11 In-field analysis may be appropriate when tracking down
illicit flows, but it is typically associated with challenging
and uncontrollable conditions. Therefore, it is generally
recommended that analyses be conducted in a controlled
lab setting.
If a subwatershed has a high density of
industrial generating sites, additional
indicator parameters may be needed to
detect and trace these unique discharges.
They are often needed because industrial
and commercial generating sites produce
discharges that are often not composed
of either sewage or washwater. Examples
include industrial process water, or wash
down water conveyed from a floor drain to
the storm drain system.

This guidance identifies seven indicator
parameters that serve as industrial flow
benchmarks to help identify illicit discharges
originating from industrial and other
generating sites. The seven indicators
(ammonia,  color, conductivity, hardness, pH,
potassium and turbidity) are used to  identify
liquid wastes and other industrial discharges
that are not always picked up by the Flow
Chart Method. Table 45 summarizes
typical benchmark concentrations that can
distinguish between unique industrial or
commercial liquid wastes. Note that  two of
the seven indicator parameters, ammonia
and potassium, are already incorporated into
the flow chart method.

Table 46 illustrates how industrial
benchmark parameters can be used
independently or as a supplement to the
flow chart method, based on data from
Alabama (Appendix E). The best industrial
benchmark parameters are identified in
pink shading and can distinguish industrial
sources  from residential washwater in
80% of samples.  Supplemental indicator
parameters denoted by yellow shading, can
distinguish industrial source from residential
washwater in 50%  of samples, or roughly
one in two samples.
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 12: Indicator Monitoring
Most industrial discharges can consistently
be identified by extremely high potassium
levels. However, these discharges would
be misclassified as washwater when just
the Flow Chart Method is used. Other
benchmark parameters have value in
identifying specific industrial types or
operations. For example, metal plating bath
waste discharges are often indicated by
extremely high conductivity, hardness and
potassium concentrations.
                 Adopting Industrial Flow Benchmark
                 By their very nature, industrial and other
                 generating sites can produce a bewildering
                 diversity of discharges that are hard to
                 classify. Therefore, program managers
                 will experience some difficulty in
                 differentiating industrial sources. Over time,
                 the composition of industrial discharges
                 can be refined as chemical libraries for
                 specific industrial flow types and sources
                 are developed. This can entail a great deal of
                 sampling, but can reduce the number of false
                 positive or negative readings.
Table 45: Benchmark Concentrations to Identify Industrial Discharges
Indicator Parameter
>50 mg/L
>500 Units
>2,000 uS/cm
<10 mg/L as CaCOS
>2,000 mg/L as CaCO3
>20 mg/L
• Existing "Flow Chart" Parameter
• Concentrations higher than the benchmark can
identify a few industrial discharges.
• Supplemental parameter that identifies a few
specific industrial discharges. Should be refined
with local data.
• Identifies a few industrial discharges
• May be useful to distinguish between industrial
• Identifies a few industrial discharges
• May be useful to distinguish between industrial
• Only captures a few industrial discharges
• High pH values may also indicate an industrial
discharge but residential wash waters can have a
high pH as well.
• Existing "Flow Chart" Parameter
• Excellent indicator of a broad range of industrial
• Supplemental parameter that identifies a few
specific industrial discharges. Should be refined
with local data.
Illicit Discharge Detection and Elimination: A Guidance Manual

                                                                     Chapter 12: Indicator Monitoring
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Chapter 12: Indicator Monitoring
Chemical Mass Balance Model
(CMBM) for Blended Flows

The Chemical Mass Balance Model
(CMBM) is a sophisticated technique
to identify flow types at outfalls with
blended flows (i.e., dry weather discharges
originating from multiple sources). The
CMBM, developed by Karri (2004) as part
of this project is best applied in complex
sewersheds with large drainage areas, and
relies heavily on the local chemical library
discussed in the next section.

The CMBM can quantify the fraction of each
flow type present in dry weather flow at an
outfall (e.g., 20% spring water; 40% sewage;
20% wash water). The CMBM relies on a
computer program that generates and solves
algebraic mass balance equations, based on
the statistical distribution of specific flow
types derived from the chemical library.
The CMBM is an excellent analysis tool, but
requires significant advance preparation and
sampling support. More detailed guidance on
how to use and interpret CMBM data can be
found in Appendix I.

The chemical library requires additional
statistical analysis to support the CMBM.
Specifically, indicator parameter data for each
flow type need to be statistically analyzed
to determine the mean, the coefficient of
variation, and the distribution type. In
its current version, the CMBM accepts two
distribution types: normal or lognormal
distributions. Various statistical metho-
dologies can determine the distribution type
of a set of data. Much of this analysis can be
conducted using standard, readily-available
statistical software, such as the Engineering
Statistics Handbook which is available from
the National Institute of Standards and
Technology, and can be accessed at http://
                  72.5  The Chemical Library

                 The chemical library is a summary of
                 the chemical composition of the range of
                 discharge types found in a community.
                 The primary purpose of the library is to
                 characterize distinct flow types that may be
                 observed at outfalls, including both clean
                 and contaminated discharges. A good library
                 includes  data on the composition of tap
                 water, groundwater, sewage, septage, non-
                 target irrigation water, industrial process
                 waters, and washwaters (e.g., laundry, car
                 wash, etc.). The chemical library helps
                 program managers customize the flow chart
                 method and industrial benchmarks, and
                 creates the input data needed to drive the

                 To develop the library, samples are collected
                 directly from the discharge source (e.g.,
                 tap water, wastewater treatment influent,
                 shallow wells, septic tanks, etc.). Table 47
                 provides guidance on how and where to
                 sample each flow type in your community.
                 As a general rule, about 10 samples are
                 typically needed to  characterize each flow
                 type, although more samples may be needed
                 if the flow type has  a high coefficient of
                 variation. The measure of error can be
                 statistically defined by evaluating the
                 coefficient of variation of the sample data
                 (variability relative to the mean value),
                 and the statistical distribution for the data
                 (the probable spread in the data beyond the
                 mean). For more guidance on statistical
                 techniques for assessing sampling  data,
                 consult Burton and  Pitt (2002) and US EPA
                 (2002), which can be accessed at http://

                 Chemical libraries should also be compared
                 to databases that summarize indicator
                 monitoring of dry weather flows at suspect
Illicit Discharge Detection and Elimination: A Guidance Manual

                                                          Chapter 12: Indicator Monitoring
outfalls. Outfall samples may not always
be representative of individual flow types
because of mixing of flows and dilution,
but they can serve as a valuable check if
the discharge source is actually confirmed.
Program managers can also use both the
chemical library and indicator database to
refine flow chart or industrial benchmarks
(see Appendix J for an example).
Over time, communities may want to add
other flow types to the chemical library, such
as transitory discharges that generate small
volume flows such as "dumpster juice,"
power washing and residential car washing.
Transitory discharges are hard to detect with
outfall monitoring, but may cumulatively
contribute significant dry weather loads.
Understanding the chemical makeup of
the transitory discharges can help program
managers prioritize education and pollution
prevention efforts.
Table 47: Where and How to Sample for Chemical "Fingerprint" Library
Flow Type
Spring Water
Tap water
Most Industrial
Commercial Car
Commercial Laundry
Places to Collect the Data
• From road cuts or stream banks
• Samples from shallow wells
• USGS regional groundwater quality data
• Dry weather in-stream flows at headwaters
with no illicit discharges
• Directly from springs
• Individual taps throughout the community
• or analyze local drinking water monitoring
reports or annual consumer confidence reports
• Collect irrigation water from several different
sites. May require a hand operated vacuum
pump to collect these shallow flows (see
Burton and Pitt, 2002)
• Reported sewage treatment plant influent data
provides a characterization of raw sewage and
is usually available from discharge monitoring
reports. Because the characteristics of
sewage will vary within the collection system
depending upon whether the area is serving
residential or commercial uses, climate,
residence time in the collection system, etc, it
is often more accurate and valuable to collect
"fingerprint" samples from within the system,
rather than at the treatment plant.
• Outflow of several individual septic tanks or
leach fields
• Direct effluent from the industrial process
(Obtain samples as part of industrial pre-
treatment program in local community)
• Sumps at these establishments
Any Other Potential Sources?
None. Locally distinct.
None. Locally distinct.
None. Locally distinct.
None. Locally distinct.
Data in Appendix E can provide
a starting point, but local data
are preferred.
Data in Appendix E characterize
some specific industrial flows.
Industrial NPDES permit
monitoring can also be used.
Data in Appendix E can provide
a starting point, but local data
are preferred.
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Chapter 12: Indicator Monitoring

Outfall sampling data for confirmed
sources or flow types can be used to test
the accuracy and reliability of all four
interpretive techniques. The sampling record
is used to determine the number of false
positives or false negatives associated with
a specific interpretive technique. A simple
tabulation of false test readings can identify
the types and levels of indicator parameters
that are most useful.

Table 48  provides an  example of how the
Flow Chart Method was tested with outfall
monitoring data from Birmingham, AL (Pitt
et al, 1993). In this case, the Flow Chart
Method was applied without adaptation to
local conditions, and  the number of correctly
(and incorrectly) identified discharges was
tracked. Tests on 10 Birmingham outfalls
were mostly favorable, with the flow chart
method correctly identifying contaminated
discharges in  all cases (i.e., washwater or
sewage waste water). At one outfall, the
flow chart incorrectly identified sewage as
washwater, based on  an ammonia (NH3)/
potassium (K) ratio of 0.9 that was very
close to the breakpoint in the Flow Chart
Method (ratio of one). Based on such tests,
program  managers may want to slightly
adjust the breakpoints in the Flow Chart
Method to minimize  the occurrence of
                                 for                or

                  The hardest discharges to detect and test
                  are intermittent or transitory discharges to
                  the storm drain system that often have an
                  indirect mode of entry. With some ingenuity,
                  luck, and specialized sampling techniques,
                  however, it may be possible to catch these
                  discharges. This section describes some
                  specific monitoring techniques to track
                  down intermittent discharges. Transitory
                  discharges cannot be reliably detected using
                  conventional outfall monitoring techniques,
                  and are normally found as a result of hotline
                  complaints or spill events. Nevertheless,
                  when transitory discharges are encountered,
                  they should be sampled if possible.


                  An outfall maybe suspected of having
                  intermittent discharges based on physical
                  indicators (e.g., staining), poor in-stream
                  dry weather water quality, or the density
                  of generating sites in the contributing
                  sub watershed. The only sure way to detect
                  an intermittent discharge is to camp out at
                  the outfall for a long period of time, which is
                  obviously not very cost-effective or feasible.
                  As an alternative, five special monitoring
                  techniques can be used to help track these
                  elusive problems:

                  •  Odd hours monitoring

                  •  Optical brightener monitoring traps

                  •  Caulk dams

                  •  Pool sampling

                  ซ  Toxicity monitoring
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Table 48: Evaluation of the Flow Chart Method Using Data from Birmingham, Alabama
(Adapted from Pitt et al., 1993)
Outfall Concentrations (mg/L)
(>0.25 is
sanitary or
wash water)
(>1.0 is
(>0.25 is
tap, if no
Flow Type
Tap Water
Tap Water
Flow Type
Spring Water
Rinse Water
and Spring
Spring Water
and Septage
Spring Water
Spring Water
and Sewage
Irrigation Water
but Incorrect
Flow Type
' These values were increased from reported values of 0.23 mg/L (outfall 28) and 0.2 mg/L (outfall 40z). The analytical
technique used in Birmingham was more precise (but more hazardous) than the method used to develop the flow chart in
Figure 47. It is assumed that these values would have been interpreted as 0.25 mg/L using the less precise method.
Odd Hours Monitoring
Many intermittent discharges actually occur
on a regular schedule, but unfortunately not
the same one used by field crews during
the week. For example, some generating
sites discharge over the weekend or during
the evening hours. If an outfall is deemed
suspicious, program managers may want to
consider scheduling "odd hours" sampling at
different times of the day or week. Some key
times to visit suspicious outfalls include:

•   Both morning and afternoon
•  Weekday evenings

•  Weekend mornings and evenings

Optical Brightener Monitoring Traps
Optical brightener monitoring (OBM)
traps are another tool that crews can use
to gain insight into the "history" of an
outfall without being physically present.
OBM traps can be fabricated and installed
using a variety of techniques and materials.
All configurations involve an absorbent,
unbleached cotton pad or fabric swatch
and a holding or anchoring device such as
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Chapter 12: Indicator Monitoring
a wire mesh trap (Figure 48) or a section
of small diameter (e.g., 2-inch) PVC pipe.
Traps are anchored to the inside of outfalls
at the invert using wire or monofilament that
is secured to the pipe itself or rocks used as
temporary weights.

Field crews retrieve the OBM traps after they
have been deployed for several days of dry
weather, and place them under a fluorescent
light that will indicate if they have been
exposed to detergents. OBM traps have been
used with some success in Massachusetts
(Sargent et a/., 1998) and northern Virginia
(Waye, 2000). Although each community
used slightly different methods, the basic
sampling concept is the same. For more
detailed guidance on how to use OBM traps
and interpret the results, consult the guidance
manual found at: http://www.naturecompass.
org/8tb/sampling/index.html and http://

Although OBM traps appear useful in
detecting some intermittent discharges,
research during this project has found
that OBM traps only pick up the most
contaminated discharges, and the  detergent
level needed to produce a "hit" was roughly
similar to pure washwater from a washing
machine (see Appendix F for results).
   Figure 48: OBM Equipment includes a
  black light and an OBM Trap that can be
            placed at an outfall
               Source: R. Pitt
                  Consequently, OBM traps may be best
                  suited as a simple indicator of presence or
                  absence of intermittent flow or to detect the
                  most concentrated flows. OBM traps need to
                  be retrieved before runoff occurs from the
                  outfalls, which will contaminate the trap or
                  wash it away.

                  Caulk Dams
                  This technique uses caulk, plumber's putty,
                  or similar substance to make a dam about
                  two inches high within the bottom of the
                  storm drain pipe to capture any dry weather
                  flow that occurs between field observations.
                  Any water that has pooled behind the dam
                  is then sampled using a hand-pump sampler,
                  and analyzed in the lab for appropriate
                  indicator parameters.

                  Pool Sampling
                  In this technique, field crews collect
                  indicator samples directly from the "plunge
                  pool" below an outfall, if one is present.
                  An upstream sample is also collected to
                  characterize background stream or ditch
                  water quality that is not influenced by the
                  outfall. The pool water and stream sample are
                  then analyzed for indicator parameters, and
                  compared against each other. Pool sampling
                  results can be constrained by  stream dilution,
                  deposition, storm water flows, and chemical
                  reactions that occur within the pool.

                  Toxicity Monitoring
                  Another way to detect intermittent discharges
                  is to monitor for toxicity in the pool below
                  the outfall on a daily basis. Burton and Pitt
                  (2002) outline several options to measure
                  toxicity, some of which can be fairly
                  expensive and complex. The  Fort Worth
                  Department of Environmental Management
                  has  developed a simple low-cost outfall
                  toxicity testing technique known as the
                  Stream Sentinel program. Stream sentinels
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                                                          Chapter 12: Indicator Monitoring
place a bottle filled with minnows in the
pool below suspected outfalls and measure
the survival rate of the minnows as an
indicator of the toxicity of the outfall12 (see
Figure 49).

One advantage of the sentinel program
is that volunteer monitors can easily
participate, by raising and caring for the
minnows, placing bottles  at outfalls, and
visiting them everyday to record mortality.
The long-term nature of sentinel monitoring
can help pick up toxicity trends at a given
outfall. For example, Fort Worth observed
a trend of mass mortality on the second
Tuesday of each month at some outfalls,
which helped to pinpoint the industry
responsible for the discharges, and improved
     Figure 49: Float and wire system to
    suspend a bottle in a stream sentinel
   station deployed in Fort Worth, TX (a);
   Minnows in the perforated bottle below
           the water surface (b).
sample scheduling (City of Fort Worth,
2003). More information about the Stream
Sentinel program can be found at: www.

Due to the cost and difficulty of interpreting
findings, toxicity testing is generally not
recommended for communities unless they
have prior experience and expertise with the

Techniques for Monitoring
Transitory Discharges

Transitory discharges, such as spills and
illegal dumping, are primarily sampled to
assign legal responsibility for enforcement
actions or to reinforce ongoing pollution
prevention education efforts. In most cases,
crews attempt to trace transitory discharges
back up the pipe or drainage area using
visual techniques (see Chapter 13). However,
field crews should always  collect a sample to
document the event. Table 49 summarizes
some  follow-up monitoring strategies to
document transitory discharges.

12.7   Monitoring of Stream
Quality During Dry Weather

In-stream water quality monitoring can
help detect sewage and other discharges in
a community or larger watershed. Stream
monitoring can identify the subwatersheds
with the greatest illicit or sewage discharge
potential that is then used to target outfall
indicator monitoring. At the smaller reach
scale,  stream monitoring may sometimes
detect major individual discharges to the
12 It may be necessary to obtain approval from the
appropriate state of federal regulatory agency before
conducting toxicity monitoring using vertebrates.
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Chapter 12: Indicator Monitoring
Table 49: Follow-Up Monitoring for Transitory Discharges
Oils or solvents
Unknown but toxic material
Probable sewage
Special hydrocarbon analysis to characterize the source of the oil
Full suite of metals, pesticides, other toxic materials
Monitor for parameters associated with the Flow Chart Technique
(detergents, ammonia, potassium, fluoride) for residential drainage
Stream Monitoring to
Identify Problem Reaches or

Stream monitoring data can be used to
locate areas in subwatersheds where illicit
discharges may be present, and where
human or aquatic health risks are higher. To
provide this information, stream monitoring
should be conducted regularly during dry
weather conditions to track water quality (at
least monthly) and to document changes in
water quality over a period of time. Stream
monitoring data are particularly effective
when combined with ORI data. For example,
a subwatershed with many ORI physical
indicators of illicit discharges (e.g., a high
number of flowing outfalls) that also has poor
stream water quality would be an obvious
target for intensive outfall monitoring.

Stream monitoring parameters should reflect
local water quality goals and objectives, and
frequently include bacteria and ammonia.
Bacteria are useful since sewage discharges
can contribute to violations of water contact
standards set for recreation during dry
weather conditions. Table 50 summarizes
water quality standards for E. coli that EPA
recommends for water contact recreation.
It is important to note that individual states
may use different action levels or bacteria
indicators (e.g., Enterococci or fecal coliform)
to regulate water contact recreation. For
a review of the impacts bacteria exert on
surface waters, consult CWP (2000).
                 An important caveat when interpreting
                 stream monitoring data is that a violation
                 of bacteria standards during dry weather
                 flow does not always mean that an
                 illicit discharge or sewage overflow is
                 present. While raw sewage has bacteria
                 concentrations that greatly exceed bacteria
                 standards (approximately 12,000 MPN/100
                 mL) other bacteria sources, such as urban
                 wildlife, can also cause a stream to violate
                 standards. Consequently, stream monitoring
                 data need to be interpreted in the context
                 of other information, such as upstream land
                 use, past complaints, age of infrastructure,
                 and ORI surveys.

                 Ideally, stream monitoring stations should
                 be strategically located with a minimum
                 of one station per subwatershed, and
                 additional stations at stream confluences and
                 downstream of reaches with a high outfall
                 density. Stations should also be located at
                 beaches, shellfish harvesting and other areas
                 where discharges represent a specific threat
                 to public health. See Burton and Pitt (2002)
                 for guidance on stream monitoring.

                 Stream Monitoring to Identify
                 Specific Discharges

                 Stream monitoring data can help field crews
                 locate individual discharges within a specific
                 stream reach. Immediate results are needed
                 for this kind of monitoring, so indicator
                 parameters should be analyzed using
                 simple field test kits or portable analytical
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                                                          Chapter 12: Indicator Monitoring
instruments (e.g., spectrophotometer).
Bacteria is not a good indicator parameter
to use for this purpose because lab results
cannot be received for at least one day
(analytical method requires a "hold time"
of 24 hours). Table 51 summarizes nutrient
indicator parameters along with their
"potential  problem level" benchmarks. It is
important  to note that other factors, such
as animal operations, can elevate stream
nutrient concentrations, so  data should
always be  interpreted in the context of
surrounding land use. Stream monitoring
benchmarks should be continuously
refined as communities develop a better
understanding of what dry weather baseline
concentrations to expect.

If stream monitoring indicates that a
potential problem level benchmark has
been exceeded, field crews continue stream
sampling to locate the discharge through a
process of elimination. Crews walk upstream
taking regular samples above and below
stream confluences until the benchmark
concentration declines. The crews then
take samples at strategic points to narrow
down the location of the discharge, using
the in-pipe monitoring strategy described in
Chapter 13.
Table 50: Typical "Full Body Contact Recreation" Standards for E. coli
(Source: EPA, 7986J1
Designated beach area
Moderately-used full body contact recreation area
Lightly-used full body contact recreation
Infrequently-used full body contact recreation
235 MPN/100 mL
298 MPN/100 mL
406 MPN/100 mL
1 These concentrations represent standards for a single sampling event. In all waters, a geometric mean
concentration of 126 MPN/100 mL cannot be exceeded for five samples taken within one month.
Table 51: Example In-Stream Nutrient Indicators of Discharges
(Zielinski, 2003)
Total Nitrogen
Total Phosphorus
Potential Problem
3.5 mg/l
0.4 mg/l
0.3 mg/l
Possible Cause of Water Quality Problem
High nutrients in ground water from agriculture, lawn
practices, or sewage contamination from illicit connection,
sanitary line break or failing septic system.
Contamination from lawn practices, agriculture, sewage or
wash water.
Sewage or washwater contamination from illicit connection,
sanitary line break or failing septic system.
"Nutrient parameters are based on USGS NAWQA data with 85% of flow weighted samples being less than these values in
urban watersheds (Note: data from Nevada were not used, due to climatic differences and for some parameters they were an
order of magnitude higher). Communities can modify these benchmarks to reflect local data and experience.
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Chapter 12: Indicator Monitoring
12.8  The        of

This section provides general guidance
on scoping and budgeting an indicator
monitoring program. The required budget
will ultimately be dictated by the monitoring
decisions and local conditions within a
community. The budgeting data presented
in this section are based on the level of
indicator sampling effort in two hypothetical
communities, using different numbers of
samples, indicator parameters, and analysis

In a

Communities can develop annual budgets
for indicator monitoring if the degree of
sampling effort can be scoped. This is
normally computed based on the expected
number of samples to analyze and is a
function of stream miles surveyed and outfall
density. For example, if a community collects
samples from 10 stream miles with eight
outfalls per mile, it will have 80 samples
to analyze. This number can be used to
generate start-up and annual monitoring cost
estimates that represent the expected level of
sampling effort. Table 52 summarizes how
indicator monitoring budgets were developed
for two hypothetical communities, each with
80 outfalls to sample. Budgets are shown
using both in-house and contract lab set-ups,
and are split between initial start-up  costs
and annual costs.

Community A: Primarily Residential
Land Use, Flow Chart Method
In this  scenario, six indicator parameters
were analyzed, several of which were used
to support the Flow Chart Method. The
community took no additional samples
to create a chemical library, and instead
                 relied on default values to identify illicit
                 discharges. The community analyzed the
                 samples in-house at a rate of one sample
                 (includes analysis of all six parameters) per
                 staff hour.

                 Community B: Mixed Land Use -
                 Multiple Potential Sources, Complex
                 In the second scenario, the community
                 analyzed 11 indicator parameters, including
                 a bacteria indicator, and took samples of
                 eight distinct flow types to create a chemical
                 library, for  a total of 88 samples. The
                 community analyzed the samples in-house at
                 a rate of one sample per 1.5 staff hours.

                 Some general rules of thumb that were used
                 for this budget planning example include the

                 ซ   $500 in initial sampling equipment (e.g.,
                     sample  bottles, latex gloves, dipper,
                     cooler, etc).

                 •   Outfall  samples are collected in batches
                     of 10. Each batch of samples can be
                     collected and transported to the lab in
                     two staff days (two-person crew required
                     to collect samples for safety purposes).

                 ซ   Staff rate is $25/hr.

                 *   Overall effort to collect samples for the
                     chemical library and statistically analyze
                     the data is approximately one staff day
                     per source type.

                 •   The staff time needed to prepare for
                     field work and interpret lab results is
                     roughly two times that required for
                     conducting the field work (i.e., eight days
                     of collecting samples requires 16 days of
                     pre- and post-preparation).
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                                                       Chapter 12: Indicator Monitoring
Costs for Intermittent Discharge

Equipment costs for most specialized
intermittent discharge techniques tend to be
low (<$500), and are dwarfed by staff effort.
As a rule of thumb, assume about four hours
of staff time to deploy, retrieve and analyze
samples collected from a single outfall using
these techniques.
Table 52: Indicator Monitoring Costs: Two Scenarios

Community A:
Community A:
Contract Lab
Community B:
Community B:
Contract Lab
Initial Costs
Initial Sampling Supplies
and Lab Equipment 1
Staff Cost: Library
Development 2
Analysis Costs: Library
Development (Reagents or
Contract Lab Cost)
Total Initial Costs
Annual Costs in Subsequent Years
Staff Field Cost (Sample
Staff Costs: Chemical
Analysis 2
Staff Time to Enter/
Interpret Data 2 6
Analysis Costs: Annual
Outfall Sampling (Reagents
or Contract Lab Cost)
Total Annual Cost
1 $500 in initial sampling equipment.
2 Samples can be shipped to a contract lab using one staff hour.
3 Overall effort to collect samples for the library and statistically analyze the data is approximately one staff day per source
4 For contract lab analysis, assume a cost that is an average between the two extremes of the range in Table 43.
5 Outfall samples are collected in batches of 10. Each batch of samples can be collected and transported to the lab in two staff
days (two-person crew required to collect samples for safety purposes).
6 Assume that the staff time needed to interpret lab results and prepare for field work is roughly 16 staff days. An additional
eight days are required for the flow type pre- and post-preparation for Community 2.
7 Staff rate is $25/hr.
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Chapter 12: Indicator Monitoring
146                         Illicit Discharge Detection and Elimination: A Guidance Manual

                                               Chapter 13: Tracking Discharges To A Source
                    13:                                       To  A
Once an illicit discharge is found, a
combination of methods is used to isolate its
specific source. This chapter describes the
four investigation options that are introduced

Field crews strategically inspect manholes
within  the storm drain network system to
measure chemical or physical indicators that
can isolate discharges to a specific segment
of the network. Once the pipe segment
has been identified, on-site investigations
are used to find the specific discharge or
improper connection.

This method relies on an analysis of land
use or other characteristics of the drainage
area that is producing the illicit discharge.
The investigation can be as simple as a
"windshield" survey of the drainage area
or a more complex mapping analysis of the
storm drain network and potential generating
sites. Drainage area investigations work best
when prior indicator monitoring reveals
strong  clues as to the likely generating site
producing the discharge.

On-site methods are used to trace the source
of an illicit discharge in a pipe segment, and
may involve dye, video or smoke testing
within  isolated segments of the storm drain

Low-density residential watersheds may
require special investigation methods if
they are not served by sanitary sewers and/
or storm water is conveyed in ditches or
swales. The major illicit discharges found in
low-density development are failing septic
systems and illegal dumping. Homeowner
surveys, surface inspections and infrared
photography have all been effectively used
to find failing septic systems in low-density


This method involves progressive sampling
at manholes in the storm drain network to
narrow the discharge to an isolated pipe
segment between two manholes. Field
crews need to make two key decisions
when  conducting a storm drain network
investigation—where to start sampling in
the network and what indicators  will be
used to determine whether a manhole is
considered clean or dirty.

        to           in the

The field crew should decide how to attack
the pipe network that contributes to a
problem outfall. Three options can be used:

•  Crews can work progressively up the
   trunk from the outfall and test manholes
   along the way.

•  Crews can split the trunk into equal
   segments and test manholes at strategic
   junctions in the storm drain system.

•  Crews can work progressively down
   from the upper parts of the storm drain
   network toward the problem  outfall.
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Chapter 13: Tracking Discharges To A Source

The decision to move up, split, or move
down the trunk depends on the nature and
land use of the contributing drainage area.
Some guidance for making this decision is
provided in Table 53. Each option requires
different levels of advance preparation.
Moving up the trunk can begin immediately
when an illicit discharge is detected at the
outfall, and only requires a map of the storm
drain system. Splitting the trunk and moving
down the system require a little more
preparation to analyze the storm drain map
to find the critical branches to strategically
sample manholes. Accurate storm drain
maps are needed for all three options. If
good mapping is not available, dye tracing
                  can help identify manholes, pipes and
                  junctions, and establish a new map of the
                  storm drain network.

                  Option 1: Move up the Trunk
                  Moving up the trunk of the storm drain
                  network is effective for illicit discharge
                  problems in relatively small drainage areas.
                  Field crews start with the manhole closest
                  to the outfall, and progressively move up
                  the network, inspecting manholes until
                  indicators reveal that the discharge is no
                  longer present (Figure 50). The goal is to
                  isolate the discharge between two storm
                  drain manholes.
Table 53: Methods to Attack the Storm Drain Network
Follow the
discharge up
Split into
Move down
the storm
Nature of Investigation
Narrow source of an individual
Narrow source of a discharge
identified at outfall
Multiple types of pollution, many
suspected problems — possibly due
to old plumbing practices or number
of NPDES permits
Drainage System
Small diameter outfall (< 36")
Simple drainage network
Large diameter outfall (> 36"),
Complex drainage
Logistical or traffic issues may
make sampling difficult.
Very large drainage area
(> one square mile).
Advance Prep
                                           O S" nurticli dieckซl - no Sow,

                                           rinflJ^msnholMrttKtad- I—*
                         Figure 50: Example investigation following
                           the source up the storm drain system
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                                               Chapter 13: Tracking Discharges To A Source
Option 2: Split the storm drain
When splitting the storm drain network,
field crews select strategic manholes at
junctions in the storm drain network to
isolate discharges. This option is particularly
suited in larger and more complex drainage
areas since it can limit the total number
of manholes to inspect, and it can avoid
locations where access and traffic are

The method for splitting the trunk is as

1.  Review a map of the storm drain
    network leading to the suspect outfall.

2.  Identify major contributing branches to
    the trunk. The trunk is defined as the
    largest diameter pipe in the storm drain
    network that leads directly to the outfall.
    The "branches" are networks of smaller
    pipes that contribute to the trunk.

3.  Identify manholes to inspect at the
    farthest downstream node of each
    contributing branch and one immediately
    upstream (Figure 51).

4.  Working up the network, investigate
    manholes on each contributing branch
    and trunk, until the source is narrowed
    to a specific section of the trunk or
    contributing branch.

5.  Once the discharge  is narrowed to a
    specific section of trunk, select the
    appropriate on-site investigation method
    to trace the exact source.
6.  If narrowed to a contributing branch,
   move up or split the branch until a
   specific pipe segment is isolated, and
   commence the appropriate on-site
   investigation to determine the source.

Option 3: Move down  the storm
drain network
In this option, crews start by inspecting
manholes at the "headwaters" of the storm
drain network, and progressively move
down pipe. This approach works best in
very large drainage areas that have many
potential continuous and/or intermittent
discharges. The Boston Water and Sewer
Commission has employed the headwater
option to investigate intermittent discharges
in complex drainage areas up to three square
miles (Jewell, 2001). Field crews certify that
each upstream branch of the storm drain
network has no contributing discharges
before moving down pipe to a "junction
manhole" (Figure 52). If discharges are
found, the crew performs dye testing to
pinpoint the discharge. The crew then
confirms that the discharge is removed
before moving farther down the pipe
network. Figure 53 presents a detailed flow
chart that describes this option for analyzing
the storm drain network.
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Chapter 13: Tracking Discharges To A Source
                                                        O     Manhole
                                                       /\    Outfall
                                                       	    Storm Drain
                                 Initial Sampling Point
            Figure 51: Key initial sampling points along the trunk of the storm drain
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                                              Chapter 13: Tracking Discharges To A Source
    Figure 52: Storm Drain Schematic Identifying "Juncture Manholes" (Source: Jewell, 2001)
      Figure 53: A Process for Following Discharges Down the Pipe (Source: Jewell, 2001)
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Chapter 13: Tracking Discharges To A Source
Dye Testing to Create a Storm
Drain Map

As noted earlier, storm drain network
investigations are extremely difficult to
perform if accurate storm drain maps are not
available. In these situations, field crews may
need to resort to dye testing to determine the
flowpath within the storm drain network.
Fluorescent dye is introduced into the storm
drain network and suspected manholes
are then inspected to trace the path of flow
through the network (U.S. EPA, 1990). Two
or three member crews are needed for dye
testing. One person drops the dye into the
trunk while the other(s) looks for evidence
of the dye down pipe.

To conduct the investigation, a point of
interest or down pipe "stopping point"
is identified. Dye is then introduced into
manholes upstream of the stopping point
to determine if they are connected. The
process continues in a  systematic manner
until an upstream manhole can no longer
be determined, whereby a branch or trunk
of the system can be defined, updated or
corrected. More information on dye testing
methods is provided in Section 13.3.

Manhole  Inspection: Visual
Observations and Indicator

Two primary methods  are used to
characterize discharges observed during
manhole inspections—visual observations
and indicator sampling. In both methods,
field crews must first open the manhole to
determine whether an illicit discharge is
present. Manhole inspections require a crew
of two and should be conducted during dry
weather conditions.

Basic field equipment and safety procedures
required for manhole inspections are outlined
                  in Table 54. In particular, field crews need
                  to be careful about how they will safely
                  divert traffic (Figure 54). Other safety
                  considerations include proper lifting of
                  manhole covers to reduce the potential for
                  back injuries, and testing whether any toxic
                  or flammable fumes exist within the manhole
                  before the cover is removed. Wayne County,
                  MI has  developed some useful operational
                  procedures for inspecting manholes, which
                  are summarized in Table 55.
                   Table 54: Basic Field Equipment Checklist
                     Camera and film or
                     digital camera


                     Field sheets

                     Field vehicle
                     First aid kit
                     Flashlight or
                     Gas monitor and
                     Manhole hook/crow
                    Storm drain,
                    stream, and street
                    Reflective safety
                    Rubber / latex
                    Spray paint
                    Tape measures

                    Traffic cones

                    Two-way radios

                    Waterproof marker/
Hand held global positioning satellite (GPS)
system receiver (best resolution available
within budget, at least 6' accuracy)
                      Figure 54: Traffic cones divert traffic
                        from manhole inspection area
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                                                  Chapter 13: Tracking Discharges To A Source
                   Table 55: Field Procedure for Removal of Manhole Covers
                                 (Adapted from: Pomeroy et a/., 1996)
 Field Procedures:
 1.  Locate the manhole cover to be removed.
 2.  Divert road and foot traffic away from the manhole using traffic cones.
 3.  Use the tip of a crowbar to lift the manhole cover up high enough to insert the gas monitor probe. Take
    care to avoid creating a spark that could ignite explosive gases that may have accumulated under the lid.
    Follow procedures outlined for the gas monitor to test for accumulated gases.
 4.  If the gas monitor alarm sounds, close the manhole immediately. Do not attempt to open the manhole
    until some time is allowed for gases to dissipate.
 5.  If the gas monitor indicates the area is clear of hazards, remove the monitor probe and position the
    manhole hook under the flange. Remove the crowbar. Pull the lid off with the hook.
 6.  When testing is completed and the manhole is no longer needed, use the manhole hook to pull the cover
    back in place. Make sure the lid is settled in the  flange securely.
 7.  Check the area to ensure that all equipment is removed from the area prior to leaving.
 Safety Considerations:
 1.  Do not lift the manhole cover with your back muscles.
 2.  Wear steel-toed boots or safety shoes to protect feet from possible crushing injuries that could occur
    while handling manhole covers.
 3.  Do not move manhole covers with hands or fingers.
 4.  Wear safety vests or reflective clothing so that the field crew will be visible to traffic.
 5.  Manholes may only be entered by properly trained and equipped personnel and when all OSHA and local
    rules a.
Visual Observations During Manhole
Visual observations are used to observe
conditions in the manhole and look for
any signs of sewage or dry weather flow.
Visual observations work best for obvious
illicit discharges that are not masked by
groundwater or other "clean" discharges,
as shown in Figure 55. Typically, crews
progressively inspect manholes in the storm
drain network to look for contaminated
flows. Key visual observations that are made
during manhole inspections include:

•   Presence of flow

•   Colors

•   Odors

•   Floatable materials

•   Deposits or stains (intermittent flows)
     Figure 55: Manhole observation (left) indicates a sewage discharge. Source is identified
        at an adjacent sewer manhole that overflowed into the storm drain system (right).
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 13: Tracking Discharges To A Source

Indicator Sampling
If dry weather flow is observed in the
manhole, the field crew can collect a sample
by attaching a bucket or bottle to a tape
measure/rope and lowering it into the
manhole (Figure 56). The sample is then
immediately analyzed in the field using
probes or other tests to get fast results as to
whether the flow is clean or dirty. The most
common indicator parameter is ammonia,
although other potential indicators  are
described in Chapter 12.

Manhole indicator data is analyzed by
looking for "hits," which are individual
samples that exceed a benchmark
concentration. In addition, trends in
indicator concentrations are also examined
throughout the storm drain network.
                 Figure 57 profiles a storm drain network
                 investigation that used ammonia as the
                 indicator parameter and a benchmark
                 concentration of 1.0 mg/L. At both the
                 outfall and the first manhole up the
                 trunk, field crews recorded finding "hits"
                 for ammonia of 2.2 mg/L and 2.3 mg/
                 L, respectively. Subsequent manhole
                 inspections further up the network revealed
                 one manhole with no flow, and a second
                 with a hit for ammonia  (2.4 mg/L). The crew
                 then tracked the discharge upstream of the
                 second manhole, and found a third manhole
                 with a low  ammonia reading (0.05 mg/L)
                 and a fourth with a much higher reading (4.3
                 mg/L). The crew then redirected its effort to
                 sample above the fourth manhole with the
                 4.3 mg/L concentration, only to find another
                 low reading. Based on this pattern, the crew
                 concluded the discharge source was located
                 between these two manholes, as nothing
                 else could explain this sudden increase in
                 concentration over this  length of pipe.

                 The results of storm drain network
                 investigations should be systematically
                 documented to guide future discharge
                 investigations, and describe any
                 infrastructure maintenance problems
                 encountered. An example of a sample
                 manhole inspection field log is displayed in
                 Figure 58.
      Figure 56: Techniques to sample
           from the storm drain
Illicit Discharge Detection and Elimination: A Guidance Manual

                                                  Chapter 13: Tracking Discharges To A Source
                               : 2.20 I

 Q     Manhole

/\    Outfall

	    Storm Drain - Discharge Unlikely

 | | | |    Storm Drain - Probable Discharge

m        Sampling Point with Concentration
                                                           Sampling Point with a "Hit"
          Figure 57: Use of ammonia as a trace parameter to identify illicit discharges
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 13: Tracking Discharges To A Source
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          Figure 58: Boston Water and Sewer Commission Manhole Inspection Log
                                (Source: Jewell, 2001)
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                                              Chapter 13: Tracking Discharges To A Source
Methods to isolate intermittent
discharges in the storm drain

Intermittent discharges are often challenging
to trace in the storm drain network, although
four techniques have been used with some

This technique involves placement of
sandbags or similar barriers within strategic
manholes in the storm drain network to
form a temporary dam that collects any
intermittent flows that may occur. Any
flow collected behind the sandbag is then
assessed using visual  observations or by
indicator sampling. Sandbags are lowered
on a rope through the manhole to form a
dam along the bottom of the storm drain,
taking care not to fully block the pipe (in
case it rains before the sandbag is retrieved).
Sandbags are typically installed at junctions
in the network to eliminate contributing
branches from further consideration  (Figure
59). If no flow collects behind the sandbag,
the upstream pipe network can be ruled out
as a source of the intermittent discharge.
Sandbags are typically left in place for
no more than 48 hours, and should only
be installed when dry weather is forecast.
Sandbags should not be left in place during a
heavy rainstorm. They may cause a blockage
in the storm drain, or, they may be washed
downstream and lost. The biggest downside
to sandbagging is that it requires at least two
trips to each manhole.

Optical Brightener Monitoring (OBM)
Optical brightener monitoring (OBM)
traps, profiled in Chapter 12, can also be
used to detect intermittent flows at manhole
junctions. When these absorbent pads are
anchored in the pipe to capture dry weather
flows, they can be used to determine the
presence of flow and/or detergents. These
OBM traps are frequently installed by
lowering them into an open-grate drop inlet
or storm drain inlet,  as shown in Figure 60.
The pads are then retrieved after 48 hours
and are observed under a fluorescent light
(this method is most reliable for undiluted
                Figure 59: Example sandbag placement (Source: Jewell, 2001)
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 13: Tracking Discharges To A Source
       Figure 60: Optical Brightener
       Placement in the Storm Drain
     (Source: Sargent and Castonguay, 1998)
Automatic Samplers
A few communities have installed automated
samplers at strategic points within the storm
drain network system that are triggered by
small dry weather flows and collect water
quality samples of intermittent discharges.
Automated sampling can be extremely
expensive, and is primarily used in very
complex drainage areas that have severe
intermittent discharge problems. Automated
samplers can pinpoint the specific date
and hours when discharges occur, and
characterize its chemical composition, which
can help crews fingerprint the generating

Observation of Deposits or Stains
Intermittent discharges often leave deposits
or stains within the storm drain pipe or
manhole after they have passed.  Thus,
crews should note whether any deposits or
stains are present in the manhole, even if
no dry weather flow is observed. In some
cases, the origin of the discharge can be
surmised by collecting indicator samples
in the water ponded within the manhole
sump. Stains and deposits, however, are not
always a conclusive way to trace intermittent
discharges in the storm drain network.
                  13.2  Drainage Area

                  The source of some illicit discharges can
                  be determined through a survey or analysis
                  of the drainage area of the problem outfall.
                  The simplest approach is a rapid windshield
                  survey of the drainage area to find the
                  potential discharger or generating sites. A
                  more sophisticated approach relies on an
                  analysis of available GIS data and permit
                  databases to identify industrial or other
                  generating sites. In both cases, drainage
                  area investigations are only effective if the
                  discharge observed at an outfall has distinct
                  or unique characteristics that allow crews
                  to quickly ascertain the probable operation
                  or business that is generating it. Often,
                  discharges with a unique color, smell, or off-
                  the-chart indicator sample reading may point
                  to a specific industrial or commercial source.
                  Drainage  area investigations are not helpful
                  in tracing sewage discharges, since they are
                  often not always related to specific land uses
                  or generating sites.

                  Rapid Windshield Survey

                  A rapid drive-by survey works well in small
                  drainage areas, particularly if field crews are
                  already familiar with its business operations.
                  Field crews try to match the characteristics
                  of the discharge to the most likely type of
                  generating site, and then inspect all of the
                  sites of the same type within the drainage
                  area until the culprit is found. For example,
                  if fuel is observed at an outfall, crews might
                  quickly check every business operation in
                  the catchment that stores or dispenses fuel.
                  Another example is illustrated in Figure
                  61 where extremely dense algal growth
                  was observed in a small stream during the
                  winter. Field crews were aware of a fertilizer
                  storage site in the drainage area, and a quick
                  inspection identified it as the culprit.
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                                               Chapter 13: Tracking Discharges To A Source
  Figure 61: Symptom (left): Discoloration of stream; Diagnosis: Extra hydroseed leftover from
 an upstream application (middle) was dumped into a storm drain by municipal officials (right).
A third example of the windshield survey
approach is shown in Figure 62, where a
very thick, sudsy and fragrant discharge
was noted at a small outfall. The discharge
appeared to consist of wash water, and
the only commercial laundromat found
upstream was confirmed to be the source.
On-site testing may still be needed to
identify the specific plumbing or connection
generating the discharge.

Detailed Drainage Area

In larger or more complex drainage areas,
GIS data can be analyzed to pinpoint the
source of a discharge. If only general land
use data exist, maps can at least highlight
suspected industrial areas.  If more detailed
SIC code data are available digitally, the
GIS can be used to pull up  specific hotspot
operations or generating sites that could
be potential dischargers. Some of the key
discharge indicators that are associated with
hotspots and specific industries are reviewed
in Appendix K.

13.3  On-site Investigations

On-site investigations are used to pinpoint
the exact source or connection producing a
discharge within the storm drain network.
The three basic approaches are dye, video
and smoke testing. While each approach
can determine the actual source of a
discharge, each needs to be applied under
the right conditions and test limitations (see
Table 56). It should be noted that on-site
investigations are not particularly effective
in finding indirect discharges to the storm
drain network.
               Figure 62: The sudsy, fragrant discharge (left) indicates that the
                 laundromat is the more likely culprit than the florist (right).
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Chapter 13: Tracking Discharges To A Source
                        Table 56: Techniques to Locate the Discharge
            Best Applications
 Dye Testing
  Discharge limited to a very small drainage
  area (<10 properties is ideal)
  Discharge probably caused by a connection
  from an individual property
  Commercial or industrial land use
• May be difficult to gain access
  to some properties
• Continuous discharges
• Discharge limited to a single pipe segment
• Communities who own equipment for other
  Relatively expensive equipment
  Cannot capture non-flowing
  Often cannot capture
  discharges from pipes
  submerged in the storm drain
 Smoke Testing
• Cross-connection with the sanitary sewer
• Identifying other underground sources (e.g.,
  leaking storage techniques) caused by
  damage to the storm drain
• Poor notification to public can
  cause alarm
• Cannot detect all illicit
  The Wayne County Department of the
 Environment provides excellent training
    materials on on-site investigations,
     as well as other illicit discharge
   techniques. More information about
    this training can be accessed from
  their website:
    Watershed/Programs	Srvcs_/
Dye Testing

Dye testing is an excellent indicator of illicit
connections and is conducted by introducing
non-toxic dye into toilets, sinks, shop drains
and other plumbing fixtures (see Figure 63).
The  discovery of dye in the storm drain,
rather than the sanitary sewer, conclusively
determines that the illicit connection exists.

Before commencing dye tests, crews should
review storm drain and sewer maps to
identify lateral sewer connections and how
they can be accessed. In addition, property
owners must be notified to obtain entry
permission. For industrial or commercial
properties, crews  should carry a letter
to document their legal authority to gain
                                   Figure 63: Dye Testing Plumbing
                                          (NEIWPCC, 2003)
                             access to the property. If time permits,
                             the letter can be sent in advance of the
                             dye testing. For residential properties,
                             communication can be more challenging.
                             Unlike commercial properties, crews are not
                             guaranteed access to homes, and should call
                             ahead to ensure that the owner will be home
                             on the day of testing.

                             Communication with other local agencies
                             is also important since any dye released
                             to the storm drain could be mistaken for a
                             spill or pollution episode. To avoid a costly
                             and embarrassing response to a false alarm,
           Illicit Discharge Detection and Elimination: A Guidance Manual

crews should contact key spill response
agencies using a "quick fax" that describes
when and where dye testing is occurring
(Tuomari  and Thomson, 2002). In addition,
crews should carry a list of phone numbers
to call spill response agencies in the event
dye is released to a stream.

At least two staff are needed to conduct dye
tests - one to flush dye down the plumbing
fixtures and one to look for dye in the
downstream manhole(s). In some cases,
Chapter 13: Tracking Discharges To A Source

three staff may be preferred, with two staff
entering the private residence or building for
both safety and liability purposes.

The basic equipment to conduct dye tests
is listed in Table 57 and is not highly
specialized. Often, the key choice is the type
of dye to use for testing. Several options are
profiled in Table 58. In most cases, liquid
dye is used, although solid dye tablets can
also be placed in a mesh bag and lowered
into the manhole on a rope (Figure 64). If a
                        Table 57: Key Field Equipment for Dye Testing
                                 (Source: Wayne County, Ml, 2000)
 Maps, Documents
   Sewer and storm drain maps (sufficient detail to locate manholes)
   Site plan and building diagram
   Letter describing the investigation
   Identification (e.g., badge or ID card)
   Educational materials (to supplement pollution prevention efforts)
   List of agencies to contact if the dye discharges to a stream.
   Name of contact at the facility
  iquipment to Find and Lift the Manhole Safely (small manhole often in a lawn)
   Metal detector
   Crow bar
   Safety equipment (hard hats, eye protection, gloves, safety vests, steel-toed boots, traffic control
   equipment, protective clothing, gas monitor)
 Equipment for Actual Dye Testing and Communications
   2-way radio
   Dye (liquid or "test strips")
   High powered lamps or flashlights
   Water hoses
     Figure 64: Dye in a mesh bag is placed into an upstream manhole (left); Dye observed
              at a downstream manhole traces the path of the storm drain (right)
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Chapter 13: Tracking Discharges To A Source
longer pipe network is being tested, and dye
is not expected to appear for several hours,
charcoal packets can be used to detect the
dye (GCHD, 2002). Charcoal packets can be
secured and left in place for a week or two,
and then analyzed for the presence of dye.
Instructions for using charcoal packets in
dye testing can be accessed at the following
                 The basic drill for dye tests consists of three
                 simple steps. First, flush or wash dye down
                 the drain, fixture or manhole. Second, pop
                 open downgradient sanitary sewer manholes
                 and check to see if any dye appears. If
                 none is detected in the sewer manhole after
                 an hour or so, check downgradient storm
                 drain manholes or outfalls for the presence
                 of dye. Although dye testing  is fairly
                 straightforward, some tips to make testing
                 go more smoothly are offered in Table 59.
Table 58: Dye Testing Options
Dye Tablets
Dye Strips
Dye Wax Cakes
Dye Wax
• Compressed powder, useful for releasing dye over time
• Less messy than powder form
• Easy to handle, no mess, quick dissolve
• Flow mapping and tracing in storm and sewer drains
• Plumbing system tracing
• Septic system analysis
• Leak detection
• Very concentrated, disperses quickly
• Works well in all volumes of flow
• Recommended when metering of input is required
• Flow mapping and tracing in storm and sewer drains
• Plumbing system tracing
• Septic system analysis
• Leak detection
• Similar to liquid but less messy
• Can be very messy and must dissolve in liquid to reach full potential
• Recommended for very small applications or for very large applications where liquid is
• Leak detection
• Recommended for moderate-sized bodies of water
• Flow mapping and tracing in storm and sewer drains
• Recommended for large sized bodies of water (lakes, rivers, ponds)
• Flow mapping and tracing in storm and sewer drains
• Leak detection
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                                                  Chapter 13: Tracking Discharges To A Source
                           Table 59: Tips for Successful Dye Testing
                             (Adapted from Tuomarl and Thompson, 2002)
 Dye Selection
 ซ  Green and liquid dyes are the easiest to see.
 ป  Dye test strips can be a good alternative for residential or some commercial applications. (Liquid can
    leave a permanent stain).
 ซ  Check the sanitary sewer before using dyes to get a "base color." In some cases, (e.g., a print shop with
    a permitted discharge to the sanitary sewer), the sewage may have an existing color that would mask a
 •  Choose two dye colors, and alternate between them when testing multiple fixtures.

 Selecting Fixtures to Test
 ซ  Check the plumbing plan for the site to isolate fixtures that are separately connected.
 ป  For industrial facilities, check most floor drains (these are often misdirected).
 ซ  For plumbing fixtures, test a representative fixture (e.g., a bathroom sink).
 ซ  Test some locations separately (e.g., washing machines and floor drains), which may be misdirected.
 ซ  If conducting dye investigations on multiple floors, start from the basement and work your way up.
 ป  At all fixtures, make sure to flush with plenty of water to ensure that the dye moves through the system.

 Selecting a Sewer Manhole for Observations
 ซ  Pick the closest manhole possible to make observations (typically a sewer lateral).
 ซ  If this is not possible, choose the nearest downstream manhole.

 Communications Between Crew Members
 •  The individual conducting the dye testing calls in to the field person to report the color dye used, and
    when it is dropped into the system.
 •  The field person then calls back when dye is observed in the  manhole.
 •  If dye is not observed (e.g., after two separate flushes have occurred), dye testing is halted until the dye

 Locating Missing Dye
 ป  The investigation is not complete until the dye is found. Some reasons for dye not appearing include:
 ซ  The building is actually hooked up to a septic system.
 ซ  The sewer line is clogged.
 ซ  There is a leak in the sewer line or lateral pipe.
Video testing works by guiding a mobile
video camera through the storm drain pipe
to locate the actual connection producing an
illicit discharge. Video testing shows flows
and leaks within the pipe that may indicate
an illicit discharge, and can show cracks and
other pipe damage that enable sewage or
contaminated water to flow into the storm
drain pipe.
Video testing is useful when access to
properties is constrained, such as residential
neighborhoods. Video testing can also be
expensive, unless the community already
owns and uses the equipment for sewer
inspections. This technique will not detect
all types of discharges, particularly when the
illicit connection is not flowing at the time of
the video survey.

Different types of video camera equipment
are used, depending on the diameter and
condition of the storm sewer being tested.
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Chapter 13: Tracking Discharges To A Source
Field crews should review storm drain maps,
and preferably visit the site before selecting
the video equipment for the test. A field visit
helps determine the camera size needed to
fit into the pipe, and if the storm drain has
standing water.

In addition to standard safety equipment
required for all manhole inspections, video
testing requires a Closed-Circuit Television
(CCTV) and supporting items. Many
commercially available camera systems are
specifically adapted to televise storm sewers,
ranging from large truck or van-mounted
systems to much smaller portable cameras.
Cameras can be self-propelled or towed.
Some specifications to look for include:

•  The camera should be capable of radial
   view for inspection of the top, bottom,
   and  sides of the pipe and for looking up
   lateral connections.

•  The camera should be color.

•  Lighting should be supplied by a lamp
   on the camera that can light the entire
   periphery of the pipe.

When inspecting the storm sewer, the
CCTV is oriented to keep the lens as close
as possible to the center of the pipe. The
camera can be self-propelled through the
pipe using a tractor or crawler unit or it
may be towed through on a skid unit (see
Figures  65 and 66). If the storm drain
                 has ponded water, the camera should be
                 attached to a raft, which floats through the
                 storm sewer from one manhole to the next.
                 To see details of the sewer, the camera
                 and lights should be able to swivel both
                 horizontally and vertically. A video record
                 of the inspection should be made for future
                 reference and repairs (see Figure 67).

                 Smoke Testing

                 Smoke testing is another "bottom up"
                 approach to isolate illicit discharges. It
                 works by introducing smoke into the storm
                 drain system and observing where the
                 smoke surfaces. The use of smoke testing to
                 detect illicit discharges is a relatively new
                 application, although many communities
                 have used it to check for infiltration
                 and inflow into their sanitary sewer
                 network. Smoke testing can find improper
                      Figure 66: Tractor-mounted camera
      Figure 65: Camera being towed
                           Figure 67: Review of an
                              inspection video
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                                               Chapter 13: Tracking Discharges To A Source
connections, or damage to the storm drain
system (Figure 68). This technique works
best when the discharge is confined to the
upper reaches of the storm drain network,
where pipe diameters are to small for video
testing and gaining access to multiple
properties renders dye testing infeasible.

Notifying the public about the date and
purpose of smoke testing before starting is
critical. The smoke used is non-toxic, but
can cause respiratory irritation, which can
be a problem for some residents. Residents
should be notified at least two weeks prior to
testing, and should be provided the following
information (Hurco Technologies, Inc., 2003):

•   Date  testing will occur

•   Reason for smoke testing

•   Precautions they can take to prevent
    smoke from entering their homes or

•   What they need to do if smoke enters
    their home or business, and any health
    concerns associated with the smoke

•   A number residents can call to relay any
    particular health concerns (e.g., chronic
    respiratory problems)

       SAND BAGS
  Figure 68: Smoke Testing System Schematic
                                               Program managers should also notify local
                                               media to get the word out if extensive
                                               smoke testing is planned (e.g., television,
                                               newspaper, and radio). On the actual day
                                               of testing, local fire, police departments
                                               and 911 call centers should be notified to
                                               handle any calls from the public (Hurco
                                               Technologies, Inc., 2003).

                                               The basic equipment needed for smoke
                                               testing includes manhole safety equipment,
                                               a smoke source, smoke blower, and sewer
                                               plugs. Two smoke sources can be used for
                                               smoke testing. The first is a smoke "bomb,"
                                               or "candle" that burns at a controlled rate and
                                               releases very white smoke visible at relatively
                                               low concentrations (Figure 69). Smoke
                                               bombs are suspended beneath a blower in a
                                               manhole. Candles are available in 30 second
                                               to three minute sizes. Once opened, smoke
                                               bombs should be kept in a dry location and
                                               should be used within one year.

                                               The second smoke source is liquid smoke,
                                               which is a petroleum-based product that
                                               is injected into the hot exhaust of a blower
                                               where it is heated and vaporized (Figure 70).
                                               The length of smoke production can vary
                                               depending on the length of the pipe being
                                                       Figure 69: Smoke Candles
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Chapter 13: Tracking Discharges To A Source
         Figure 70: Smoke blower
tested. In general, liquid smoke is not as
consistently visible and does not travel as far
as smoke from bombs (USA Blue Book).

Smoke blowers provide a high volume of
air that forces smoke through the storm
drain pipe. Two types of blowers are
commonly used: "squirrel cage" blowers
and direct-drive propeller blowers. Squirrel
cage blowers are large and may weigh
more than 100 pounds, but allow the
operator to generate more controlled smoke
output. Direct-drive propeller blowers are
considerably lighter and more compact,
which allows for easier transport and

Three basic steps are involved in smoke
testing. First, the storm drain is sealed off by
plugging storm drain inlets. Next, the smoke
is released and forced by the blower through
the storm drain system. Lastly, the crew
looks for any escape of smoke above-ground
to find potential leaks.

One  of three methods can be used to seal off
the storm drain. Sandbags can be lowered
into place with a rope from the street
surface. Alternatively, beach balls that have
a diameter slightly larger than the drain
can be inserted into the pipe. The beach
ball is then placed in a mesh bag with a
                 rope attached to it so it can be secured and
                 retrieved. If the beach ball gets stuck in the
                 pipe, it can simply be punctured, deflated
                 and removed. Finally, expandable plugs are
                 available, and may be inserted from the
                 ground surface.

                 Blowers should be set up next to the open
                 manhole after the smoke is started. Only
                 one manhole is tested at a time. If smoke
                 candles are used,  crews simply light the
                 candle, place it in a bucket, and lower it in
                 the manhole. The crew then watches to see
                 where smoke escapes from the pipe. The
                 two most common situations that indicate
                 an illicit discharge are when smoke is seen
                 rising from internal plumbing fixtures
                 (typically reported by residents) or from
                 sewer vents. Sewer vents extend upward
                 from the sewer lateral to release gas buildup,
                 and are not supposed to be connected to the
                 storm drain system.

                  13.4  Septic System

                 The techniques for tracing illicit discharges
                 are different in rural  or low-density
                 residential watersheds. Often, these
                 watersheds lack sanitary sewer service and
                 storm water is conveyed through ditches
                 or swales, rather than enclosed pipes.
                 Consequently, many  illicit discharges enter
                 the stream as indirect discharges, through
                 surface breakouts of  septic fields or through
                 straight pipe discharges from bypassed
                 septic systems.

                 The two broad techniques used to  find
                 individual septic systems—on-site
                 investigations and infrared imagery—are
                 described in this section.
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                                                Chapter 13: Tracking Discharges To A Source
Three kinds of on-site investigations can
be performed at individual properties to
determine if the septic system is failing,
including homeowner survey, surface
condition analysis and a detailed system
inspection. The first two investigations are
rapid and relatively simple assessments
typically conducted in targeted watershed
areas. Detailed system inspections are
a much more thorough investigation of
the functioning of the septic system that
is conducted by a certified professional.
Detailed system inspections may occur at
time of sale of a property,  or be triggered by
poor scores on the rapid homeowner survey
or surface condition analysis.

Homeowner Survey
The homeowner survey consists of a brief
interview with the property owner to
determine the potential for current or future
failure of the septic system, and is often
done in conjunction with a surface condition

Table 60 highlights some common questions
to ask in the survey, which inquire about
resident behaviors, system performance and
maintenance activity.
Surface Condition Analysis
The surface condition analysis is a rapid
site assessment where field crews look for
obvious indicators that point to current or
potential production of illicit discharges by
the septic system (Figure 71). Some of the
key surface conditions to analyze have been
described by Andrews et a/., (1997) and are
described below:

•   Foul odors in the yard

•   Wet,  spongy ground; lush plant growth;
    or burnt grass near the drain field

•   Algal blooms or excessive weed growth
    in adjacent ditches, ponds and streams

ซ   Shrubs or trees with root damage within
    10 feet  of the system

ซ   Cars, boats, or other heavy objects
    located over the field that could crush
    lateral pipes

ซ   Storm water flowing over the drain field

•   Cave-ins or exposed system components

•   Visible liquid on the surface of the drain
    field (e.g., surface breakouts)

•   Obvious system bypasses (e.g., straight
    pipe discharges)
                    Table 60: Septic System Homeowner Survey Questions
                     (Adapted from Andrews et a/,, 1997 and Holmes Inspection Services)
   How many people live in the house?1
   What is the septic tank capacity?2
   Do drains in the house empty slowly or not at all?
   When was the last time the system was inspected or maintained?
   Does sewage back up into the house through drain lines?
   Are there any wet, smelly spots in the yard?
   Is the septic tank effluent piped so it drains to a road ditch, a storm sewer, a stream, or is it connected to
   a farm drain tile?
 * Water usage ranges from 50 to 100 gallons per day per person. This information can be used to estimate the wastewaterload
  from the house (Andrews et. a/, 1997).
 2 The septic tank should be large enough to hold two days' worth of wastewater (Andrews et. a/, 1997).
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 13: Tracking Discharges To A Source
    Figure 71: (a) Straight pipe discharge to nearby stream, (b) Algal bloom in a nearby pond.
                        (Sources: a- Snohomish County, WA,  b- King County, WA)
Detailed System Inspection

The detailed system inspection is a
much more thorough inspection of the
performance and function of the septic
system, and must be completed by a certified
professional. The inspector certifies the
structural integrity of all components of the
system, and checks the depth of solids in
the septic tank to determine if the system
needs to be pumped out. The inspector also
sketches the system, and estimates distance
to groundwater, surface water, and drinking
water sources. An example septic system
inspection form from Massachusetts can be
found at
wwm/soil sy s .htm.

Although not always incorporated into
the inspection, dye testing can sometimes
point to leaks from broken pipes, or direct
discharges through straight pipes that might
be missed during routine inspection. Dye
can be introduced into plumbing fixtures
in the home, and flushed with sufficient
running water. The inspector then watches
the septic field, nearby ditches, watercourses
and manholes for any signs of the dye. The
                  dye may take several hours to appear, so
                  crews may want to place charcoal packets in
                  adjacent waters to capture dye until they can
                  return later to retrieve them.

                  Infrared Imagery
                  Infrared imagery is a special type of
                  photography with gray or color scales that
                  represent differences in temperature and
                  emissivity of objects in the image (www.
        , and can be used to
                  locate sewage discharges. Several different
                  infrared imagery techniques can be used
                  to identify illicit discharges. The following
                  discussion highlights two of these: aerial
                  infrared thermography13 and color infrared
                  aerial photography.

                  Infrared Thermography
                  Infrared thermography is increasingly
                  being used to detect illicit discharges and
                  failing septic systems. The technique uses
                  the temperature difference of sewage as
                  a marker to locate these illicit discharges.
                  Figure 72 illustrates the thermal difference
                                                13 Infrared thermography is also being used by communities
                                                such as Mecklenburg County and the City of Charlotte in
                                                NC to detect illicit discharges at outfalls.
Illicit Discharge Detection and Elimination: A Guidance Manual

                                               Chapter 13: Tracking Discharges To A Source
between an outfall discharge (with a higher
temperature) and a stream.

The equipment needed to conduct aerial
infrared thermography includes an aircraft
(plane or helicopter); a high-resolution, large
format, infrared camera with appropriate
mount; a GPS unit; and digital recording
equipment. If a plane is used, a higher
resolution camera is required since it must
operate at higher altitudes. Pilots  should be
experienced since flights take place at night,
slowly, and at a low altitude. The  camera
may be handheld, but a mounted camera
will provide significantly clearer results for
a larger area. The GPS can be combined
with a mobile mapping program and a video
encoder-decoder that encodes and displays
the coordinates, date, and time (Stockton,
2000). The infrared data are analyzed
after the flight by trained analysts to locate
suspected discharges, and field crews then
inspect the ground-truthed sites to confirm
the presence of a failing septic system.

Late fall, winter, and early spring are
typically the best times of year to conduct
these investigations in most regions of the
country. This allows for a bigger difference
between receiving water and discharge
temperatures, and interference from
vegetation is minimized (Stockton, 2004b).
In addition, flights should take place at night
to minimize reflected and direct daylight
solar radiation that may adversely affect the
imagery (Stockton, 2004b).

Color Infrared Aerial Photography
Color infrared aerial photography looks
for changes in plant growth, differences in
soil moisture content, and the presence of
standing water on the ground to primarily
identify failing septic systems (Figure 73).

The Tennessee Valley Authority (TVA) uses
color infrared aerial photography to detect
failing septic systems in reservoir watersheds.
Local health departments conduct follow-up
ground-truthing surveys to determine if a
system is actually failing (Sagona, 1986).
Similar to thermography, it is recommended
that flights take place at night, during leaf-
off conditions, or when the water table is at
a seasonal high (which is when most failures
typically occur (U.S. EPA, 1999).
  Figure 72: Aerial thermography showing
               sewage leak
   Figure 73: Dead vegetation and surface
   effluent are evidence of a septic system
             surface failure.
           (Source: U.S. EPA, 1999)
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 13: Tracking Discharges To A Source
13.5  The Cost to Trace Illicit
Discharge Sources

Tracing illicit discharges to their source
can be an elusive and complex process,
and precise staffing and budget data are
difficult to estimate. Experience of Phase I
NPDES communities that have done these
investigations in the past can shed some light
on cost estimates. Some details on unit costs
for common illicit discharge investigations
are provided below.

Costs for Dye, Video, and Smoke
The cost of smoke, dye, and video testing
can be substantial and staff intensive, and
                 often depend on investigation specific
                 factors, such as the complexity of the
                 drainage network, density and age of
                 buildings, and complexity of land use.
                 Wayne County, MI, has estimated the cost of
                 dye testing at $900 per facility. Video testing
                 costs range from $1.50 to $2.00 per foot,
                 although this increases by $1.00 per foot if
                 pipe cleaning is needed prior to testing.

                 Table 61 summarizes the costs of start-up
                 equipment for basic manhole entry and
                 inspection, which is needed regardless of
                 which type of test is performed. Tables
                 62 through 64 provide specific equipment
                 costs for dye, video and smoke testing,
Table 61: Common Field Equipment Needed
for Dye, Video, and Smoke Testing
1 Digital Camera
Clipboards, Pens, Batteries
1 Field vehicle
1 First aid kit
1 Spotlight
1 Gas monitor and probe
1 Hand-held GPS Unit
2 Two-way radios
1 Manhole hook
1 Mirror
2 Reflective safety vests
Rubber/latex gloves (box
of 100)
1 Can of Spray Paint
4 Traffic Cones
$15,000 -$35,000
$900 -$2,100
$250 - $750
$80 -$130
$70 -$130
Illicit Discharge Detection and Elimination: A Guidance Manual

                                             Chapter 13: Tracking Discharges To A Source
Table 62: Equipment Costs for Dye Testing
Dye Strips
Dye Tablets
Liquid Concentrate
(Rhodamine WT)
Dye Wax Cakes
Dye Wax Donuts
Water Volume
1 strip/500 gallons
0-50,000 gallons
0-50, 000 gallons
50,000 + gallons
20,000 - 50,000 gallons
50,000 + gallons
$75 -$94 per 100 strips
$40 per 200 tablets
$80 -$90 per gallon
$15 -$20 per pint
$12 per one 1 .25 ounce cake
$104 - $132 per 42 oz. donut
Price Sources:
Aquatic Eco-Systems
Cole Farmer http:/www.
USA Blue Book http:/www.
Table 63: Equipment Costs for Video Testing
GEN-EYE 2™ B&W Sewer Camera with VCR & 200' Push Cable
100' Push Rod and Reel Camera for 2" - 10" Pipes
200' Push Rod and Reel Camera for 8" - 24" Pipes
Custom Saturn III Inspection System
500' cable for 6-16" Lines
• Box with build-out
• Generator
• Washdown system
Video Inspection Trailer
• 7'x1 0' trailer & build-out
• Hardware and software package
• Incidentals
Sprinter Chassis Inspection Vehicle
• Van (with build-out for inspecting 6" - 24" pipes)
• Crawler (needed to inspect pipes >24")
• Software upgrade (optional but helpful for extensive pipe systems)
($33, 000 with 1000 foot
Sources: USA Blue Book and Envirotech
Table 64: Equipment Costs for Smoke Testing
Smoke Blower
Liquid Smoke
Smoke Candles,
Smoke Candles,
Smoke Candles,
30 second (4,000 cubic feet)
60 Second (8,000 cubic feet)
3 Minute (40,000 cubic feet)
$1,000 to $2, 000 each
$38 to $45 per gallon
$27.50 per dozen
$30. 50 per dozen
$60. 00 per dozen
Sources: Hurco Tech, 2003 and Cherne Industries, 2003
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 13: Tracking Discharges To A Source

Most septic system investigations are
relatively low cost, but factors such as
private property access, notification, and
the total number of sites investigated can
increase costs. Unit costs for the three major
septic system investigations are described

Homeowner Survey and Surface
Condition Analysis
Both the homeowner survey and the surface
condition analysis are relatively low cost
investigation techniques. Assuming that
a staff person can investigate one home
per hour, the average cost per inspection
is approximately  $25. A substantial cost
savings can be realized by using interns
or volunteers to conduct these simple

Detailed System Inspection
Septic system inspections are more
expensive, but a typical unit cost is about
$250, and may also include an additional
cost of pumping the system, at roughly
$150, if pumping is required to complete the
inspection (Wayne County, 2003). This cost
is typically charged to the homeowner as
part of a home inspection.
                 Aerial Infrared Thermography
                 The equipment needed to conduct aerial
                 infrared thermography is expensive;
                 cameras alone may range from $250,000
                 to $500,000 (Stockton, 2004a). However,
                 private contractors provide this service.
                 In general, the cost to contract an aerial
                 infrared thermography investigation depends
                 on the length of the flight (flights typically
                 follow streams or rivers); how difficult it
                 will be to fly the route; the number of heat
                 anomalies expected to be encountered;
                 the expected post-flight processing time
                 (typically, four to five hours of analysis for
                 every hour flown); and the distance of the
                 site from the plane's "home" (Stockton,
                 2004a). The cost range is typically $150
                 to $400 per mile of stream or river flown,
                 which includes the flight and post-flight
                 analyses (Stockton, 2004a).

                 As an alternative,  local police departments
                 may already own an infrared imaging
                 system that may be used. For instance,
                 the Arkansas Department of Health used
                 a state police helicopter with a Forward
                 Looking Infrared (FLIR) imaging system,
                 GPS, video equipment, and maps (Eddy,
                 2000). The disadvantage to this is that  the
                 equipment may not be available at optimal
                 times to conduct the investigation. In
                 addition, infrared imaging equipment used
                 by police departments may not be sensitive
                 enough to detect the narrow range of
                 temperature difference (only a few degrees)
                 often expected for sewage flows (Stockton,
Illicit Discharge Detect/on and Elimination: A Guidance Manual

                                                   Chapter 14: Techniques to Fix Discharges
                        14:                       to  Fix
Quick and efficient correction of illicit
discharges begins with having well defined
legal authority and responsibilities coupled
with strong enforcement and follow-up
measures. Chapter 4 discussed important
considerations with respect to legal
authority and responsibility and Appendix B
contains a model illicit discharge ordinance
that provides language on violations,
enforcement and penalties.

Most illicit discharge corrective actions
involve  some form of infrastructure
modification or repair. These structural
repairs are used to eliminate  a wide variety
of direct discharges such as sewage cross-
connections, straight pipes, industrial
cross-connections, and commercial cross-
connections. Fixes range from simple
plumbing projects to excavation and
replacement of sewer lines. In some cases,
structural repairs are necessary when
indirect discharges, such as sewage from
a sewer break or pump station failure enter
the MS4 through an inlet, or flows directly
into receiving waters. Most transitory
discharges are corrected simply with spill
containment and clean-up procedures.
Section 8.3 previously discussed an
overview of the correction process. The
following section discusses more specific
correction considerations.


Once the source of an  illicit discharge has
been identified, steps should be taken to fix
or eliminate the discharge. The following
four questions should be answered for each
individual illicit discharge to determine how
to proceed:

•  Who is responsible?

ป  What methods will be used to fix it?

•  How long will it take?

•  How will removal be confirmed?

The answer to each of these questions
depends on the source of the discharge.
Illicit discharges generally originate from
one of the following sources:

*  An internal plumbing  connection (e.g.,
   the discharge from a washing machine is
   directed to the building's storm lateral;
   the floor drain in a garage is connected
   to the building's storm lateral)

•  A service lateral cross-connection (e.g.,
   the sanitary lateral from a building is
   connected to the MS4)

•  An infrastructure failure within the
   sanitary sewer or MS4 (e.g., a collapsed
   sanitary line is discharging into the MS4)

•  An indirect transitory discharge
   resulting from leaks, spills, or overflows.

Financial responsibility for source  removal
will typically fall on property owners, MS4
operators, or some combination of the two.

                      for        the

Ultimate responsibility for removing the
source of a discharge is generally that of either
the property owner or the municipality/utility
(e.g., primary owner/operator of the MS4).
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 14: Techniques to Fix Discharges
Internal Plumbing Connection
The responsibility for correcting an
internal plumbing connection is generally
the responsibility of the building owner.
Communities may wish to develop a list of
certified contractors that property owners
can hire for corrections.

Service Lateral
As with internal plumbing connections,
the responsibility for correcting a problem
within a service lateral is typically that of the
property owner being served by the lateral.
However, the cost of correcting a service
lateral problem can be significantly higher
than that of fixing an internal plumbing
problem, so communities may want to
consider alternative remedial approaches
than those for internal plumbing corrections.
For example, communities can have on-
call contractors fix lateral connections
allowing the problem to be fixed as soon as
it is discovered. The community can then:
1) pay for correction costs through the capital
budget, or state or federal funding options, or
2) share the cost with the owner, or 3) pass
on the full cost to the property owner.

Infrastructure Failure Within the
Sanitary Sewer or MS4
Illicit discharges related to some sort of
infrastructure failure within the sanitary
sewer or MS4 should be corrected by the
jurisdiction, utility, or agency responsible for
maintenance of the sewers and drains.

Transitory Discharge
Repair of transitory discharge sources will
usually be the responsibility of the property
owner where the discharge originates.
Ordinances should clearly stipulate the time
frame in which these discharges should be
                                    will be       to fix

                  The methods used to eliminate discharges
                  will vary depending on the type of problem
                  and the location of the problem. Internal
                  plumbing corrections can often be performed
                  using standard plumbing supplies for
                  relatively little cost. For correction locations
                  that occur outside of the building, such as
                  service laterals or infrastructure in the right
                  of way, costs tend to be significantly more
                  due to specialized equipment needs. Certified
                  contractors are recommended for these types
                  of repairs. Table 65 provides a summary of
                  a range of methods for fixing these more
                  significant problems along with estimated
                  costs. The last six techniques described in
                  Table 68 are used for sanitary sewer line
                  repair and rehabilitation. These activities
                  are typically used when there is evidence  of
                  significant seepage from the sanitary system
                  to the storm drain system.


                  The timeframe for eliminating a connection
                  or discharge should depend on the type of
                  connection or discharge and how difficult
                  elimination will be. A discharge that
                  poses a significant threat to human or
                  environmental health  should be discontinued
                  and eliminated immediately. Clear guidance
                  should be provided in the local ordinance  on
                  the timeframe for removing discharges and
                  connections. Typically, discharges should
                  be stopped within seven days of notification
                  by the municipality, and illicit connections
                  should be repaired within 30 days of

                        Is the            or

                  Removal and correction of a discharge or
                  connection should be  confirmed both at the
Illicit Discharge Detect/on and Elimination: A Guidance Manual

                                                   Chapter 14: Techniques to Fix Discharges
source, to ensure that the correction has
been made, and downstream, to ensure that
it is the only local discharge present.

For discharges resulting from internal
plumbing and lateral connections, dye
testing can confirm the correction. Also,
sandbagging should be done in the first
accessible storm drain manhole downstream
of the correction to verify that this was the
only discharge present.

The correction of discharges resulting
from some sort of infrastructure failure in
the sanitary sewer or MS4 can be verified
by dye testing or televising the line in
conjunction with sandbagging and sampling
at an accessible downstream manhole.
Table 65: Methods to Eliminate Discharges
1. Service Lateral
2. Cleaning
3. Excavation and
4. Manhole Repair
5. Corrosion
Control Coating
6. Grouting
7. Pipe Bursting
8. Slip Lining
9. Fold and
Formed Pipe
Lateral is connected to
the wrong line
Line is blocked or
capacity diminished
Line is collapsed,
severely blocked,
significantly misaligned,
or undersized
Decrease ponding;
prevent flow of surface
water into manhole;
prevent groundwater
Improve resistance to
Seal leaking joints and
small cracks
Line is collapsed,
severely blocked, or
Pipe has numerous
cracks, leaking joints,
but is continuous and not
Pipe has numerous
cracks, leaking joints
Lateral is disconnected and reconnected
to appropriate line
Flushing (sending a high pressure water
jet through the line); pigging (dragging a
large rubber plug through the lines); or
Existing pipe is removed, new pipe
placed in same alignment; Existing pipe
abandoned in place, replaced by new
pipe in parallel alignment
Raise frame and lid above grade;
install lid inserts; grout, mortar or apply
shortcrete inside the walls; install new
precast manhole.
Spray- or brush-on coating applied to
interior of pipe.
Seals leaking joints and small cracks.
Existing pipe used as guide for inserting
expansion head; expansion head
increases area available for new pipe
by pushing existing pipe out radially
until it cracks; bursting device pulls new
pipeline behind it
Pulling of a new pipe through the old
Similar to sliplining but is easier to install,
uses existing manholes for insertion; a
folded thermoplastic pipe is pulled into
place and rounded to conform to internal
diameter of existing pipe
Estimated Cost
For 14" line, $50-
(higher number is
associated with
repaying or deeper
excavations, if
Vary widely, from
$250 to raise a
frame and cover to
~ $2, 000 to replace
Fora 12" line, ~
For 8" pipe, $40-
For 12" pipe, $50-
$75 /linear foot2
For 8-12" pipe, $60-
Illicit Discharge Detection and Elimination: A Guidance Manual

Chapter 14: Techniques to Fix Discharges
                            Table 65: Methods to Eliminate Discharges
  Estimated Cost
 10. Inversion
Pipe has numerous
cracks, leaking joints;
can be used where there
are misalignments
Similar to sliplining but is easier to install,
uses existing manholes for insertion;
a soft resin impregnated felt tube is
inserted  into the pipe, inverted by filling
it with air or water at one end, and cured
in place.
 1 CWP (2002)
 2 1991 costs from Brown (1995)
 3 U.S. EPA (1991)
 4 U.S. EPA (1999b)
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