7 IDDE Program Plan 2020 updated August

Illicit Discharge
Detection and Elimination
Program
Town of Carrboro
August 2020

Foreword
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) less than
desirable improvement in receiving water conditions may occur. Illicit dry -weather flows
can originate from many sources. The most important sources typically include sanitary
wastewater, commercial, or industrial pollutant entries, failing septic tank systems, and
vehicle maintenance activities. Other sources can contribute, depending on land use
patterns and activities within the watershed.
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 Program Plan details the approach the Town of Carrboro has established for Illicit
Discharge Detection and Elimination (IDDE). Its intended audience is Town staff for
understanding the implementation of the program, State and Federal agency staff for
oversight and review, volunteers that are interested in providing reconnaissance and
public awareness support, and the general public for community education. The Plan
draws on work performed by the Center for Watershed Protection, Ellicott City, MD in
cooperation with Robert Pitt of the University of Alabama under the sponsorship of the
U.S. Environmental Protection Agency (Brown et al 2004).
This plan is organized in two parts:
Section 1. The Basics of Illicit Discharges — This section describes the many different
sources and generating sites that can produce illicit discharges. The section also outlines
key concepts and terminology needed to understand illicit discharges, why they cause
water quality problems and the regulatory context for managing them.
Section 2. Carrboro's Illicit Discharge Program — This section presents the overall
framework for Carrboro's IDDE program by outlining key components of the program.
This section also defines program goals to guide efforts, as well as guidance on how to
measure and track progress toward their achievement and review and revisit goals and
make any needed adjustments. Finally, this section identifies the local implementation
steps for the program.

Section 1: The Basics of Illicit Discharges
Studies have shown that dry weather flows from storm drain systems may contribute
significantly to pollution problems (e.g., Duke 1997). Detecting and eliminating these illicit
discharges can involve 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. As a
small Phase II community, Carrboro needs simple but effective guidance to implement
the illicit discharge component of its NPDES stormwater permit.
The discussion below draws on the experience of many communities that have been
surveyed about their practices, levels of program effort, and lessons learned (CWP,
2002). These communities have taken many different approaches to address illicit
discharges, and in doing so, provided insights on common obstacles and realistic
expectations. In Section 2, the lessons learned and unique aspects of Carrboro are
integrated into a program plan.
1.1 Important Terminology and Key Concepts
This section defines the terminology to help staff perform illicit discharge detective work.
Key concepts are presented to classify illicit discharges, generating sites and control
techniques.
Illicit Discharge: The term "illicit discharge" has many meanings in regulation' and
practice; this plan employs this four-part definition.
1. Illicit discharges are defined as storm drains that have measurable flow during dry
weather containing pollutants and/or pathogens. A storm drain with measurable flow but
containing no pollutants is simply considered a discharge.
2. Each illicit discharge has a unique frequency, duration, 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. In Carrboro, monitoring techniques are employed by OWASA to
rapidly trace sewage flows from the stream or outfall, and go back up the pipes or
conveyances to reach the problem connection.
4. Illicit discharges from types of activities and specific source areas and operations are
known as "generating sites." Knowledge about these generating sites is 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.
1 140 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

Carrboro has defined illicit discharges as part of an illicit discharge ordinance in Section
5, Article IV of the Town Code. Some non -storm water discharges to the municipal
separate storm system (MS4) are allowable, such as discharges resulting from fire
fighting activities and air conditioning condensate.
Storm Drain: 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 storm 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 often
needed to confirm whether pollutants are actually present in dry weather flow, in order to
classify them as an illicit discharge.
Discharge Frequency: The frequency of dry weather discharges in storm drains is
important, and can be classified as continuous, intermittent or transitory. 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 relatively small number of 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.

Discharge Flow Types: Dry weather discharges are composed of one or more possible
flow types:
• Sewage and septage flows are produced from sewer pipes and septic systems.
• Washwater flows are generated from a wide variety of activities and operations.
Examples include discharges of gray water 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.
• Landscape irrigation flows occur when excess 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 can be 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.
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.
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.
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. Older industrial areas
tend to have a higher potential for illicit cross -connections.
Sewage likely has the greatest potential to produce direct illicit discharges within
Carrboro. On a national scale, 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).
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
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
typically occur at 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.
Dumping a liquid: 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,
ditch, or stream. 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.
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. In some instances, non -target
irrigation can produce unacceptable loads of nutrients, organic matter or pesticides. A
common example is a discharge from commercial landscaping areas adjacent to parking
lots or roads connected to the storm drain system.
Land Use and Potential Generating Sites: 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. Both research and program
experience indicates that a small subset of generating sites within a broader land use

category can produce most of
potential generating sites within
local illicit discharge problems.
categories are listed in Table 1,
the indirect discharges. Consequently, the density of
a subwatershed may be a good indicator of the risk of
Some common generating sites within major land use
and described below.
Carrboro intends to use land use as a general risk factor for illicit discharges. More specific risk
factors 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. The large number
of new connections and/or disconnections during these phases increases the probability of bad
plumbing. Carrboro intends to work cooperatively with OWASA to identify the risk of illicit
sewage discharges.
Table 1 Site Activities in Carrboro with the Highest Potential to Produce Illicit Discharges
Residential
Car Washing
Swimming Pool Discharges
Driveway Cleaning
DumpingSpills
Septic System Maintenance
Lawn/Landscape Watering
Commercial/Institutional/Municipal
Commercial
Car Washes
Laundry/DryLaundry/Dry Cleaning
Gas Stations/Auto Repair Shops
Nurseries and Garden Centers
Oil Change Shops
Restaurants
Building Maintenance power washing)
Dumping/Spills
Landscaping/Grounds Care (irrigation)
Municipal Fleet Storage Areas
Public Works Yard
Outdoor Fluid Storage
Parking Lot Maintenance power washing)
Road Maintenance Town and State
Vehicle Fueling
Vehicle Maintenance/Repair
Vehicle Washing
Washdown of greasy equipment and grease traps
Printing
Loadingand unloading area washdowns
Outdoor material storage fluids
Under round storage tanks fuel
Residential Generating Sites: Failing septic systems were the most common residential
discharge reported in 33% of IDDE programs surveyed nationally (CWP, 2002). In
addition, indirect residential discharges were 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.
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. It is important to note that not all businesses within a generating
category actually produce illicit discharges; generally only a relatively small fraction does.
Consequently, on -site inspections of individual businesses are needed to confirm whether
a property is actually a generating site.

Institutional Generating Sites: Institutions such as schools and churches can be
generating sites if routine maintenance practices/operations create discharges from
parking lots and other areas. Some institutional sites have their own areas for fleet
maintenance, fueling, outdoor storage, and loading/unloading that can produce indirect
discharges.
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 town and state roads and rail lines
can also generate indirect discharges from spills, accidents and dumping.
1.2 Finding, Fixing, and Preventing Illicit Discharges
The purpose of Carrboro's IDDE program is to find, fix and prevent illicit discharges, and
develop a series of techniques to meet these objectives. These primary objectives are
briefly introduced below.
Finding Illicit Discharges
The highest current priorities for Carrboro's IDDE is to find any continuous and
intermittent sewage discharges to the storm drain system, and to perform reconnaissance
on high risk outfalls and generating areas. Observational and, where appropriate,
monitoring techniques will be used to find sewage discharges and then trace the problem
back to identify the ultimate generating site or connection. These techniques can be
classified into three major groups:
• Outfall Reconnaissance Inventory
• Indicator monitoring at stormwater outfalls and instream
• Tracking discharges to their source
Fixing Illicit Discharges
Once sewage discharges or other connections or discharging activities are discovered,
they can be fixed, repaired or eliminated. Fixing an illicit discharge can involve plumbing
repairs, behavioral changes/training, such as educating employees about proper disposal
of oil and grease at a restaurant or proper management of dumpsters, or infrastructure
repairs if there is a cross connection or faulty sewer line resulting in sewage entering the
stormwater conveyance system. It can also involve actions such as replacing or properly
maintaining a septic tank.

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 a
targeted education program, pollution prevention practices and well -executed spill
management and response plans.

Section 2: Carrboro's IDDE Program
The prospect of developing and administering an IDDE program can be complex and
challenging for small municipalities like Carrboro. This section organizes and simplifies
the basic tasks proposed for Carrboro's program. Carrboro plans to pursue the program
components, as summarized in Table 2 and elaborated on below.
Table 2: Illicit Discharge Requirements in Carrboro's Stormwater Permit
1. Maintain adequate
The Town will annually review and revise the Town's IDDE ordinance as necessary,
legal authorities
and adopt any additional regulatory mechanisms that provide the Town with adequate
legal authority to prohibit illicit connections and discharges and enforce the approved
IDDE Program.
2. Maintain storm water
The Town shall maintain a current map of the stormwater system that includes major
system inventory,
outfalls and receiving streams
including major outfalls
that discharge to waters
of the State
3. Detect dry weather
The Town shall develop and implement a program for conducting dry weather flow
flows and investigate
field observations with a written procedure for detecting and removing the sources of
the source of all
illicit discharges. The Town shall maintain, and evaluate annually written procedures
identified illicit
for conducting investigations of identified illicit discharges.
discharges.
4. Track investigations
The Town shall track all investigations and document the date(s) the illicit discharge
and document illicit
was observed; the results of the investigation; any follow-up of the investigation; and
discharges.
the date the investigation was closed.
5. Employee Training
The Town shall implement and document a training program for appropriate
municipal staff, who, as part of their normal job responsibilities, may come into
contact with or otherwise observe an illicit discharge or illicit connection to the storm
sewers stem.
6. Provide Public
The Town will inform public employees, businesses, and the general public of
Education
hazards associated with illegal discharges and improper disposal of waste.
7. Public reporting
The Town will promote, publicize, and facilitate a reporting mechanism for the public
mechanism
and staff to report illicit discharges and establish and implement citizen request
response procedures.
8. Enforcement
The Town shall implement a mechanism to track the issuance of notices of violation
and enforcement actions administered by the Town. This mechanism shall include
the ability to identify chronic violators for initiation of actions to reduce
noncompliance.
Maintain Adequate Legal Authorities: The Town developed an illicit discharge
ordinance effective in June 20082. The ordinance addresses: discharges that are
prohibited; discharges that are permissible; exemptions; requirements for correction;
and enforcement and penalties. The Town relies on the Orange County Director of
Environmental Health Services for regulation of onsite wastewater systems. Carrboro's
Building Inspections staff enforce building code provisions. OWASA staff also have
requirements in place to ensure that inappropriate connections are prohibited. The
2 available at http://www.townofcarrboro.org/TC/towncode.htm (Chapter 5, Article IV of the Town Code)

Town has followed EPA guidance in addressing categories of identified types of non-
stormwater discharges that will not be addressed as illicit discharges because of either
the nature of the discharges or conditions the Town establishes for allowing these
discharges to the system.
Storm Sewer System Inventory: The Town initiated a detailed stormwater mapping
program in 2000. The program involves inventorying all storm drainage facilities within
the Town's corporate limits and ETJ. All drainage structures (public and private) have
been mapped, including surveying of all public structures. Mapping has been enhanced
as new digital and as -built information has become available. The mapping program
includes determination of the following:
• Horizontal and vertical location of storm drainage structures and open end
culverts
• Sizes and types of the piping connecting the drainage structures
• Type and condition of storm drainage structures.
• Visual inspection of each structure to detect illicit discharges or other
irregularities.
• All outfalls greater than 36" diameter or draining greater than 50 acres are
considered to be major outfalls. Additional major outfalls have been identified
based primarily on land use in the contributing drainage area.
Field location of the facilities and other information related to each structure have been
input into GIS by a survey team using a lap top computer. Elevations of the tops and
inverts of the storm drainage structures have been field surveyed using available
vertical control (i.e. NCGS monuments, OWASA manholes, other bench marks) and
input into GIS. Subsequent GIS analyses have been completed to connect open
channel conveyances and distinguish between these conveyances and ephemeral
streams. As new field determinations of state regulated intermittent and perennial
streams are completed, the GIS database is updated, resulting in a connected and
complete stormwater/surface water database.
The Town completed a major update to stream data in FY2008-2009 that improved the
accuracy and classification of perennial, intermittent, and ephemeral streams. The
Town also completed a major update to the mapped stormwater system that included
drainage areas, outfalls, ditches, BMPs, and new system features subsequent to the
original mapping. Illicit discharges are hard enough to find if an organized system to
track individual outfalls is lacking.
Public Works has taken the lead on developing a tracking system for stormwater inlets
and in outfall tracking system. Stormwater/Public Works staff have been inspecting
storm drainage structures for discoloration, odor, and the presence of liquids other than
water or anything else within the structure that would indicate past or intermittent illicit
discharge.
Carrboro will continue to pursue steps to further document and understand the
infrastructure. Indirect or transitory discharges are difficult to catch through outfall

screening. Scrutiny of the history and condition of the storm water and sewer
infrastructure will assist in identifying the greatest risk for illicit discharge. Additional
information will be brought to bear. For example, knowing the proximity of the
infrastructure to the groundwater table or knowing the sewer collection transit time can
assist in risk identification and detection procedures.
Detection and Investigation: The Town has initiated detection and investigation
procedures and will continue to explore ways to improve upon these procedures.
Successful detection and elimination programs have used a wide array of techniques.
Inspection and monitoring of the system often involves dry weather flow investigations
to determine the presence of illicit connections, the establishment of priority sites that
may need more extensive investigation, and a reporting system for the public to notify
officials of questionable activities.
The Town is focusing on the highest risk areas based on land use and age of
infrastructure. The Town has very little industrial and light industrial activity. The highest
risks are associated with commercial activities, leaking sewer lines, and improper waste
disposal. The priority area currently being focused on includes much of downtown and
adjacent areas draining to Tanbark Branch, Tom's Creek, and an unnamed tributary
flowing south from downtown.
The Town has pursued physical and chemical monitoring in the past in cooperation with
Chapel Hill; these efforts have been of limited utility for illicit discharge detection and
elimination. The Town plans to pursue IDDE monitoring recommendations provided by
the Center for Watershed Protection and Dr. Pitt from the University of Alabama, in a
project completed under contract to EPA.
• The Town plans to use primarily existing Town staff that routinely are out
in the community (fire protection, public safety, zoning and inspections,
streets, and sanitation crews) as the front line in identifying potential
problems. By training these staff in identifying potential problems and
proper response protocol, the Town can efficiently use existing resources
to implement a detection team approach to this part of the program.
• One example of training and a routine activity is physically inspecting the
Town's right-of-ways to identify illicit discharges.
• Working with OWASA to identify sanitary sewer connections and respond
to sewer overflows/spills.
• Remediation of hazardous chemical spills (Fire and Safety, Public Works).
• Outfall reconnaissance surveys and stream walks (Stormwater)
• Building/plumbing inspections including floor drains (Building Inspectors).
Planning staff initiated and Stormwater staff has continued an Outfall Reconnaissance
Inventory (ORI). The ORI focuses on major outfalls identified as part of system mapping
to quantify the severity of dry weather discharge problems. The ORI will be conducted
regularly as part of the IDDE program. A tracking mechanism is being created in
CityWorks to manage data collected during the inventory.

Carrboro will seek IDDE reconnaissance support from local watershed groups as
volunteer labor is identified. The emphasis is to have as many "informed eyes" on
potential illicit discharges in the community as possible. Carrboro is fortunate to have
citizen groups, including the Friends of Bolin Creek and the Morgan Creek Valley
Alliance, who can help observe outfalls and stream quality, and support storm water
education. Carrboro is also fortunate to share a boundary with Chapel Hill that has an
active stormwater education program, and to have UNC nearby. All of these factors
increase local watershed awareness and stewardship.
Monitoring could be the most expensive component of the IDDE program, so it is
extremely important to understand existing discharges before committing to a particular
monitoring method or tracer. Carrboro will also consider opportunities to collaborate with
OWASA and Chapel Hill for any identified future chemical monitoring needs. Carrboro
has historically maintained a benthic macro invertebrate monitoring program, and will
also investigate redesign of this program to support the IDDE program.
Track investigations and document illicit discharges : When illicit discharge
problems are found, the next step is to trace them back to isolate the specific source or
improper connection that generates them. This component addresses locating and
documenting specific discharges
Public Education: Raising community wide awareness of storm water issues will
assist the Town in its efforts to reduce pollutant run-off. Informative outreach and
training programs will be developed to train and inform residents, businesses, and town
personnel of the following:
• Unpermitted practices
• Proper avenues for incident response
• Proper disposal of waste
• Irresponsible storm water management and the effect on the environment.
The Town has participated in an initiative led by UNC and Chapel Hill focusing on IDDE
education for priority business sectors, and will use lessons learned to focus efforts for
those sectors. The Town has also worked with NCSU/Cooperative Extension Service to
provide IDDE training and will use the materials created in future trainings. The Town
works with Orange County Director of Environmental Health Services for outreach
regarding onsite wastewater systems.
Carrboro will stress public health and safety benefits of sewage -free streams. Carrboro
will work with OWASA to publicize the danger of sewage discharges, and notify the
public about the discharges that need to be prevented or corrected.
Public Reporting Mechanism: Clear and accessible reporting and communication
protocol for the program is paramount to successful implementation. The Town's
website has this information. Carrboro will integrate wide dissemination of this
information into Public Education and Outreach efforts, e.g., through the Stormwater

newsletter, social media, newsflashes, community events, and direct outreach to
important sectors and community stakeholders. Clear information is provided to help
point the responding party to whether the first point of contact should be emergency
response (911/Fire and Rescue), OWASA, Public Works, Planning within Town
government as well as other public agencies. The identified staff contacts for each of
these entities will be cross trained in communication protocol to facilitate rapid and
efficient response, especially for transitory events. Stormwater has established a hotline
number, email address, and an online form for reporting Stormwater issued including
IDDE.
, pF CAPo.,
https://townofcarrboro.org/FormCenter/Public-Works-Department-23/Stormwater-Service-Request-
134
Enforcement: The Town will continue to enforce its ordinance. Enforcement support is
provided by Building Inspectors, Zoning staff, the Police Department, and Town
Attorney.
Tips for Program Success
Below are some tips on how Carrboro plans to build an effective IDDE program.
Carrboro has put together an interdisciplinary and Interdepartmental IDDE team. A broad
range of expertise needs to be coordinated to develop the initial IDDE program, as
indicated in Table 3. Diverse skills and knowledge needed for the program range from
thorough review and understanding of the program through review of this plan, legal
analysis, GIS, monitoring, stakeholder management, emergency response, and pipe
repairs. The Stormwater and GIS staff will maintain the system map. The Stormwater
Division will also coordinate with the Fire and Rescue, Police, and other departments
regarding employee training. These processes and responsible individuals are detailed
in the BMP table above. The Stormwater Division will be the lead for Steps 1, 2, 5, and 6,
and overall permit compliance and program implementation. The Stormwater Specialist
position assumes the lead responsibility. The GIS Analyst position maintains core GIS
data pertinent to the program. Sungate Engineering has performed field work to map the
storm water system. The Town Attorney is providing legal support with Town Code

drafting under Step 1. The Attorney will also provide legal assistance with future
enforcement actions.
As the lead organization for management and maintenance of Carrboro's public
infrastructure, the Department of Public Works is identified as the lead department for
routine field observation (Steps 3 and 4). Public Works will be substantially supported by
Zoning and Inspections staff within the Planning Department, and Fire and Rescue and
Public Safety staff. From outside of Town staff, OWASA, Sungate Engineering (the
Town's engineering firm), Orange County Erosion and Sediment Control and Health
Department staff, and citizen volunteers primarily from the two nonprofits, the Friends of
Bolin Creek and the Morgan Creek Valley Alliance will also be trained in field recognition
and reporting of potential problems for follow up. Along the municipal boundary with
Chapel Hill, Carrboro will closely coordinate its program with Chapel Hill's Stormwater
program staff.
One atypical consideration for program implementation in Carrboro is the delineation of
authority and responsibility for sewage related illicit discharges since the sewage
collection system is managed by a non -municipal utility, OWASA. Carrboro's IDDE
program relies on OWASA's sewer ordinance and sewer lateral policy for detection and
elimination of illicit sewage discharges. Detection and elimination of illicit discharges
from sewer lines located in public right-of-ways will require cooperation with OWASA.
Detection and elimination of illicit discharges from sewer laterals located outside public
right-of-ways will require cooperation from OWASA and property owners.
The ensuing sections and appendix address each IDDE program component in more
detail, including purpose, methods, desired product or outcome, budget implications, and
other detailed guidance for program implementation. Table 2 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
3.
Carrboro will pursue detection and elimination of 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 found. Intermittent, transitory, or indirect discharges are
harder to detect, and more difficult to fix.
Carrboro will educate a broad audience about illicit discharges. Illicit discharge control is
a somewhat confusing program to many staff, the public, elected officials, and other local
agencies. The success of this program will in large part be a function of the success in
educating all four groups.
Carrboro will cross -train local inspectors and emergency responders to recognize
discharges and report them for enforcement. Carrboro's program will ensure that,

building, zoning, water and wastewater, health, and erosion control inspectors and fire
and rescue staff understand illicit discharges and know whom to contact locally for
enforcement.
Carrboro will target limited storm water education dollars. Carrboro has limited resources
to perform the amount of storm water education needed to reduce indirect and transitory
discharges. Consequently, Carrboro will target discharges of concern, and focus on the
subwatersheds, neighborhoods and sectors most likely to generate them. Carrboro will
work collaboratively with the Clean Water Education Partnership, local media, the
Chamber of Commerce, Advisory Boards, Chapel Hill, OWASA, UNC, and citizens
groups to maximize the effectiveness and cost effectiveness of education efforts.
Carrboro will calibrate resources to the magnitude of the illicit discharge problem.
Carrboro will get a better handle on the actual severity of illicit discharge problems over
time. The program is therefore designed to be flexible and adaptive, and will shift
resources to the management measures that will reduce the greatest amount of pollution.
Carrboro will think of illicit 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.

Program Goals and Implementation Strategies
This section discusses the goals and performance milestones to measure progress in
Carrboro's IDDE program implementation, and 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.
IDDE program goals (as detailed in Table 3) will be linked to stream water quality goals.
Water quality goals include:
• keeping raw or poorly -treated sewage out of streams
• meeting bacteria water quality standards during dry weather flows
• reducing toxicant, nutrient and other pollutant discharges to streams to restore the
abundance and diversity of aquatic biota and help meet established TMDLs
Based on knowledge of stressors to local waterbodies, Carrboro's IDDE program is seen
as one of multiple watershed protection and restoration programs. Over time as staff
determines the degree to which illicit discharges contribute to impaired water quality,
resources (both time and money) can be shifted amongst all the programs to most
effectively meet the water resource goals.

I dull a. %rMFWULU s LJt:LdI1t:U ILJLJC rrUUFdfll UUdib d11U OLMUUMU
Goals related to overall program administration
❑ Identify organizational structure for IDDE program (this plan)
❑ Draft and promulgate new ordinance (completed in FY 2007-2008)
❑ Establish a tracking and reporting system (update in FY 2020-2021)
Goals related to outfall assessment
[]Define and characterize stormwater system and sewer sheds for all major outfalls (FY 2008-2009; updated
in 2020)
❑ Develop a GIS map of all outfalls, land use, and other relevant infrastructure (complete; updates ongoing).
❑ Secure analytical laboratory services, as needed
❑ Sample and trace the source of a percentage of flowing outfalls. (no flowing outfalls identified to date.)
❑ continue to conduct regular benthic monitoring.
❑ Identify highest priority outfalls to conduct investigations study water quality and look for intermittent
flows. (Expand and enhance where problems are observed.)
Goals related to preventing illicit discharges
❑Distribute educational materials to citizens and priority businesses. Initiated in FY 2012-2013; expand and
enhance as needed
❑ Conduct storm drain stenciling. (Completed; refresh)
❑ Publicize Orange County household hazardous waste collection (on website and in trainings; ongoing)
❑ Conduct subwatershed site reconnaissance surveys to better characterize generating site potential
(ongoing)
Goals related to finding and fixing illicit discharges
❑ Publicize spill response plan via website (Ongoing)
❑ Remove all obvious illicit discharges. (Ongoing)
❑ Train staff on techniques to find the source of an illicit discharge. (Ongoing)
❑ Inspect/dye-test selected commercial facilities if warranted.
❑ Develop a system to track results of on -site inspections. (Ongoing)
❑ Recruit citizen volunteers to monitor outfalls and streams by subwatershed. (Expand in FY 2020/21)
❑ Install/maintain signage at key locations to streams that will display identification and contact information
for reporting issues. ( FY2021-2022)
Table 4 presents potential implementation strategies. Strategies should be constantly
adjusted to reflect knowledge gained from field screening, reports and other monitoring
information.
Perhaps the most important implementation strategy is targeting —screening, education
and enforcement efforts should always be focused on the catchments or generating sites
with the greatest IDP. Ongoing adaptability is also an important program objective. Table
5 presents more detailed implementation components depending on specific issues that
Carrboro could encounter.

Table 4: Examples of General Implementation Strategies for Different Levels of Illicit
Discharge Potential (IDP)
❑ Minimal IDP Target and coordinate with Friends of Bolin Creek and Morgan Creek Valley Alliance (or
others identified) as partners to accomplish inventory and data collection efforts.
❑ ❑Establish communication protocol to report suspicious discharges.
Clustered IDP
❑Conduct limited sampling in the suspect areas. Use field kits first, then outside laboratory services to avoid
significant costs for special equipment.
❑ ❑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.
❑Coordinate with local watershed groups to regularly monitor problem areas.
❑ Establish communication protocol to report suspicious discharges.
Severe IDP (if encountered)
❑ ❑ Establish communication protocol to report suspicious discharges.
❑ Conduct and repeat screening in all subwatersheds/sewer sheds
❑ ❑ Plan for more rigorous sampling approach (i.e., plan for equipment expenditures/contracting 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. Use outside laboratory services as needed to supplement.
❑ ❑ Develop community -wide educational messages aimed at increasing public awareness and targeted
education programs tailored to problem areas.
❑ Coordinate with local watershed groups to regularly monitor problem areas.
❑ ❑ Emphasize cross -training of municipal employees to develop a broader reach of program efforts and lead
by example.

Table 5: Potential Types of Problems and Candidate Detection and Elimination Strategies
Initial Problem
Assessment Screening Factor
Example Implementation
Strategies
Aging Sewer Infrastructure
Complaints of sewage discharges
Institute inspection process.
Dry weather discharge/poor dry
Select monitoring indicator
weather quality
parameters that focus on sewage.
High outfall density
Develop cost share program to
assist property owners with
connection correction.
Aging Septic Infrastructure
Dry weather discharge/poor dry
Develop targeted education
weather quality
program
Complaints
Institute inspection process
Septic to sewer conversion:
develop cost share capabilities to
assist property owners with
upgrade of system.
Discharges from Generating
Dry weather discharge/poor dry
Develop targeted
Sites
weather quality
inspection/training/technical
Density of generating sites
assistance programs tailored to
Older commercial activity
specific generating sites.
Complaints
Aggressively enforce fines and
other measures on chronic
violators
High Spill or Dumping Potential
Past complaints
Establish clear communication
protocol for reporting
Develop communitywide education
program
Establish protocol to regularly
monitor/adopt problem sites
References
Brown, Edward,, Caraco, Brown Deb, and Robert Pitt2. 2004. Illicit Discharge Detection and Elimination: A
Guidance Manual for Program Development and Technical Assessments. EPA Cooperative Agreement X-
82907801-01. 1. Center for Watershed Protection Ellicott City, Maryland Ellicott City, MD; 2. University of
Alabama, Tuscaloosa, Alabama
Center for Watershed Protection. 2002. Unpublished Task I Technical Memorandum: Phase I Community
Surveys in Support of Illicit Discharge Detection and Elimination Guidance Manual. IDDE project support
material.
Duke, L.R. 1997. Evaluation of Non -Storm Water Discharges to California Storm Drains and Potential Policies
for Effective Prohibition. California Regional Water Quality Control Board. Los Angeles, CA.
Schueler, T. 2004. An Integrated Framework to Restore Small Urban Watersheds. Center for Watershed
Protection, Ellicott City, MD.

Appendix A: Technical Approach to Monitoring for IDDE program
This section presents Carrboro's plan for monitoring to identify the composition of illicit
discharge flows. The section includes a flow chart approach that utilizes chemical
indicators. The section provides specific information on proper safety, handling, and
disposal procedures. Simple and more sophisticated methods for interpreting monitoring
data are discussed, along with comparative cost information. From a program
management standpoint, core issues need to be considered during the design of the
monitoring strategy. 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. The discussion below 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 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 flow type (Pitt, 2004). The flow chart method is particularly suited to
distinguish sewage and washwater flow types. More complex methods are available for
industrial sites, but are not included herein.
Develop a monitoring strategy
• -IF-At a minimum, sample 10% of flowing outfalls per year
• -CUse monitoring methods appropriate to outfall designation and subwatershed
characteristics
• ❑❑Use OR[ 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 discharges
• ❑ El Develop a chemical library of concentrations for various flow types
• ❑❑Estimate staff time, and costs for equipment and disposable supplies
The Flow Chart Method
Carrboro will test the "Flow Chart Method", which 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 (2004). 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 are described below:

Figure 47: Flow Chart to Identify Illicit discharges in Residential watersheds
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.
Step 2: Separate washwater from wastewater 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 pollutants.
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. Staff 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, staff 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, staff
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. An expanded flow
chart can provide more consistent and detailed identification of flow types, but obviously
requires more analytical work and data analysis.
Single Parameter Screening
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 sewage
contamination. An ammonia concentration greater than 1 mg/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. 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. 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 CardyTM is the recommended probe).
While the flow chart method and indicators will provide a foundation, Carrboro may
investigate other indicators to supplement this method. The following is a list of
indicators that Carrboro will consider in developing IDDE monitoring capabilities.
Acidity — refers to the capability of a sample to neutralize a base. Indicates corrosive
properties. Not to be confused with pH.
Alkalinity — refers to the capability of a sample to neutralize an acid. A measure of buffering
capacity. Not to be confused with pH.
Ammonia (NH3 / NH4') — Indicator of sanitary sewer leaks but also widely used for fertilizer,
disinfectant, and cleanser. Also a combustion product. Readily transformed by bacteria to
nitrite.
Boron (B+) — borate is used for "color -safe bleach" as well as a pool -chemical disinfectant, boric
acid is used as a mild antiseptic and for organic insectides. Borate is a good laundry indicator
especially when phosphate -free detergents are used.
Caffeine — the D+Caf test goes down supposedly to 3.5mg/L —enough to detect whether your
decaf coffee/tea is really decaf. This could be used as a potential indicator of sanitary sewer
leaks, however, the existing method seems to be confusing to read and not very
accurate. Carrboro may want to find a lab that could do caffeine analysis, as a check for
suspected sanitary sewer leaks, but right now there are no field methods available.
Chlorine — indicators of drinking water but also laundry detergent/bleach, pool chemicals
(Chlorine Dioxide, hypochlorite, and chlorine gas used for water treatment, Hypochlorite is also

laundry bleach). It is possible to measure free available chlorine, chlorine dioxide, hypochlorite
ion, chloramines, and total available residual chlorine.
Some important definitions:
Free available residual chlorine - that portion of the total available residual chlorine
composed of dissolved chlorine gas c12), hypochlorous acid (HOCI), and/or hypochlorite
ion (OCI-) remaining in water after chlorination. This does not include chlorine that has
combined with ammonia, nitrogen, or other compounds.
Total available residual chlorine — the amount of available chlorine remaining after a given contact
time. The sum of the combined available residual chlorine and the free available residual chlorine.
Combined available chlorine — chloramines or chlorine compounds that disinfect
Coliform/Bacteria — Indicators of sanitary sewer leaks, but also other bacterial
sources. There's so many different ways to screen for bacteria, including type. For example:
Lamotte has indicator kits for coliform, aerobic bacteria, sulfate -reducing bacteria, bacteria and
fungi, and generic bacteria.
Lamotte has kits specifically for testing activity/population size of sulfate -reducing bacteria,
slime -forming bacteria, iron -related bacteria, heterotrophic aerobic bacteria, micro -algae,
fluorescent pseudomonas, denitrifying bacteria, and nitrifying bacteria.
Conductivity — Conductivity measures everything dissolved in water (as to its
conductance). This can be very useful when there is a high load of solutes, probably indicative
of some kind of non -natural source, but may include analytes we can't detect or just too many of
them.
Detergents/Surfactants — they're not exactly the same thing, but with regard to water testing
they are both measuring the presence of products used for cleaning/washing everything from
body soap, laundry detergent, car wash, etc. Even "bio-degradable" products have them in
them. Detergents and surfactants are extremely toxic to aquatic life.
Fluoride (F-) — an indicator of drinking water because of fluoridation, concentrations above
0.25mg/L are suggested for differentiating between a natural water source and tap or irrigation
water. Dilute hydrofluoric acid (HF) is used for glass etching and recently for wheel cleaner
compounds.
Forma ldehyde/GIuteraldehyde — Formaldehyde is naturally occurring in combustion
products. Both aldehydes are used as commercial, health care, and industrial disinfectants
(these are what we are most likely to see being dumped), as well as for preserving animal
tissue.
Hardness — is a measure of scaling minerals, but also includes an aspect of alkalinity
(carbonate minerals). Primarily calcium, magnesium, iron, and manganese. Our ground water
is fairly soft, so a hard water sample is indicative of some other source.

Nitrate (NO3-) — Primary source is through fertilizers, although ammonia is converted to nitrate
through nitrite. Indicator of fertilizer wash -off, but also metabolized sanitary sewer water.
Nitrite (NOz") — Primary source is metabolized ammonia/ammonium. Can be used to detect
sanitary sewer waters that may have filtered through soil.
pH —indicator of relative acidity/alkalinity. Unusually acidic or alkaline values can help identify a
potential pollution problem and source.
Phosphate — Orthophosphates are bioavailable and present in sewage and
fertilizers. Metaphosphates have been used in detergents and boiler waters (but have been
replaced by zeolites). Orthophosphates are readily measured, whereas metaphosphates
require processing. Total inorganic (ortho and meta) must be boiled with acid prior to
processing
Potassium (K+) — used to distinguish between sanitary sewer contamination and washwater
contamination. It's also present in weed killers and fertilizers.

Appendix B: IDDE Field Guidance
Contents
Field Inspection Checklist....................................................................8
Physical Indicators.............................................................................11
Color..............................................................................................11
Odor..............................................................................................12
Sewage, Sheens & Surface Scum..................................................12
Outfall Condition...........................................................................15
Outfall Classifications........................................................................15
Biological Indicators..........................................................................16
Storm Drain Network Investigations.................................................17
Tier 1 Chemical Parameters..............................................................18

Field Inspection Checklist
❑ ❑ Monitoring test kits
❑ ❑ Test meters (pH, conductivity, turbidity)
❑ ❑ Protective gloves for handling chemicals
❑ ❑ Sunscreen, poison ivy cream, first aid kit
❑ ❑ Safety goggles, hard hat, closed -toed shoes and/or rubber boots
❑ ❑ Container for bringing back liquid reagent wastes from the field
❑ ❑ Bottle of deionized or distilled water for rinsing equipment after sampling
❑ ❑ Extendable pole with attached sampling cup
❑ ❑ Paper towels or rags
❑ ❑ Field sheets/forms (See Appendix C Templates)
❑ ❑ Storm drain, stream, and street maps
❑ ❑ Tape measure or ruler
❑ ❑ Standard camera,
❑ Inspection camera/mirror
❑ ❑ Cell phone or two-way radio
❑ ❑ Handheld GPS unit or GIS capable smart phone/tablet
❑ -1 Inspection notification letter documenting legal authority to gain access to
property during field inspection (See Appendix C Templates)
❑ ❑ Contact information of police and emergency response personnel in case of
spills or active illicit discharges
❑ ❑ Notification of the public and/or property owners if necessary (See Appendix C
Templates)
❑ Marking paint/flagging (white or pink)
❑ Small dry erase board and marker to ID photos
❑ Caution tape and/or cones
❑ Clip board
❑ Flashlight
❑ Tablet/Smart Phone
❑ Manhole pick

START
Evaluate Land Use
in Area I
r Flaw N❑ Presence oftvuo YE5
or more physical POTENTIAL ILLICIT
obse rued? DISCHARGE
indicators?
YES
IN
Measure flow and re -Inspect location
test water FUNKELY ILLICIT later
chemistry CHARGE
Do resu Its of Tier
I tests or physical N�
indicators suggest
illicit discharge?
Use smoke,
dye, or video
YES testing
Tier II NO
samples SUSPECT ILLICIT Trace Discharge
necessary? DISCHARGE Source
NO
YES
Collect water Do Tier II tests YES
samples for indicate an illicit OBVIOUS ILLICIT
Tier II lab discharge? DISCHARGE

Land Use Generating Sites
by Sector
Residential ❑Apartments
• ❑ Multi -family
• []Single family
Commercia • ❑Campgrounds/RV parks
[]Car dealers/ car rentals
•
❑ Car washes
•
❑Commercial laundry/dry
cleaning
•
[]Gas stations/auto repair
•
❑ Marinas
•
El Nurseries and garden
centers
•
[]Oil change shops
•
❑ Restaurants
•
❑Swimming pools
Industrial •
❑Auto recyclers/scrap yards
•
[]Beverage makers and
breweries
•
El Construction vehicle
washouts
•
❑ Distribution centers
•
[]Food processing
•
❑Garbage truck washouts
•
❑ Boat building and repair
•
[]Metal plating operations
•
[]Paper and wood products
•
[]Petroleum storage
•
❑ Printing
Institutional •
❑Cemeteries
.
[]Churches
.
[]Corporate campuses
.
❑ Hospitals
•
[]Schools and universities
Municipal
[]Airports
.
[]Animal shelters
.
❑ Landfills
•
[]Maintenance depots
•
[]Municipal fleet storage areas
•
[]Public works yards
•
[]Streets and highways
Discharge -Producing
Activities
• ❑Car washing
• []Driveway cleaning
• ❑Dumping/spills
• ❑ Equipment washdowns
• ❑ Lawn/landscape watering
• ❑Septic system maintenance
• ❑Swimming pool discharges
• ❑ Build ing/parking lot maintenance (power
washing)
• ❑ Dumping/spills
• ❑ Landscaping/grounds care
• []Outdoor material storage
• ❑Vehicle fueling/washing
• ❑Vehicle maintenance/repair
• El Grease trap/equipment cleaning
• ❑AII commercial activities
• ❑ Industrial process water or rinse water
• []Loading and unloading area washdowns
• ❑ Outdoor material storage
• ❑Building/parking lot maintenance (power
washing)
• ❑ Dumping/spills
• ❑Landscaping/grounds care ❑Vehicle
washing
• ❑ Building/parking lot maintenance (power
washing)
• ❑Dumping/spills
• ❑ Landscaping/grounds care
• []Outdoor materials storage
• ❑ Road maintenance
• ❑Spill prevention/response
• ❑Vehicle fueling/washing
• ❑Vehicle maintenance/repair

Physical Indicators
Color
Color
Possible Sources
1 Tan to light brown
Suspended sediments common after • rainfall
Runoff from construction, roads, -
agricultural/range land
Soil erosion caused by vegetation • removal
2 Pea green, bright
Algae or plankton bloom - color depends • on
green, yellow, brown,
type of algae or plankton
brown -green, brown-
Sewage, fertilizer runoff, vehicle wash • water
yellow, blue-green
3 Tea/coffee
Dissolved or decaying organic matter • from soil
or leaves. Commonly associated with tree
overhangs, woodlands, or swampy areas
4 Milky white
Paint, lime, milk, grease, concrete, • swimming
pool filter backwash
5 Milky or dirty
Gray water or wastewater, musty odor • present
dishwater gray
6 Milky gray -black
Raw sewage discharge or other oxygen —
demanding waste (rotten egg or hydrogen
sulfide odor may be present)
7 Clear black
Caused from turnover of oxygen-• depleted
waters or sulfuric acid spill
8 Dark red, purple,
Fabric dyes, inks from paper and • cardboard
blue, black
manufacturers
9 Orange -red
Leachate from iron deposits -
Deposits on stream beds often • associated
with oil well operations (check for petroleum
odor)
10 White crusty deposits
Common in dry/arid areas or during • periods of
low rainfall where evaporation of water leaves
behind salt deposits
Also found in association with brine • water
discharge from oil production areas (a
petroleum odor or an oily sheen may be present
along banks)
11 Other
Describe

Fill sample bottle at least halfway with sample water and hold about six inches away
from your nose. Use your free hand to fan the scent to your nose. Note: never inhale the
air directly off the top of a sample as many potential contaminants are harmful to nasal
membranes and lung tissue. Make sure that the origin of the odor is at the outfall.
Sometimes shrubs, trash, or even spray paint used to mark the outfalls can confuse the
nose.
Odor
1 Rotten eggs/hydrogen
sulfide (septic)
2 Chlorine
3 Sharp, pungent odor
4 Musty odor
5 Gasoline, petroleum
6 Sweet, fruity
Other
Sewage, Sheens & Surface Scum
General Causes
Raw sewage, decomposing organic
matter, lack of oxygen
Wastewater treatment plant
discharges, swimming pool
overflow, industrial discharges
Chemicals or pesticides
Presence of raw or partially treated
sewage, livestock waste
Industrial discharge, illegal dumping of
wastes, waste water
Commercial wash water,
wastewater
Describe
Contaminated flows may contain floatable solids or liquids. Sewage, oil sheen, and
suds/foam are examples of floatable indicators. Trash and debris, although more
typically known as "floatables," are not generally indicators of illicit flow.
• Sheens can be naturally -produced or synthetic; oil sheens are often mistaken for
naturally -produced sheen.
• Sheen from bacteria forms a sheet -like film that breaks if disturbed. Suds should
be rated based on their foaminess and staying power.
• Suds that travel several feet before breaking up should be considered as a
possible illicit discharge.
• In some cases, foam and suds can give off an odor.
• A strong organic or sewage -like odor can indicate a sanitary sewer leak or
overflow.
• A fragrant or sweet smelling odor can indicate the presence of laundry water or
similar wash waters.

Surface Scum
General Causes
Tan foam
Usually associated with high flow or wave
action; wind action plus flow churns water
containing organic materials causing
harmless foam; produces small patches
to very large clumps.
White foam
Sometimes patchy or covering wide area
around wastewater outFall, thin and
billowy, mostly due to soap.
Yellow, brown, black
Pine, cedar, and oak pollens form film on
film
surface, especially in ponds, backwater
areas, or slow moving water in streams.
Rainbow film
If a swirling pattern, then likely oil or other
fuel type. Check for petroleum odor. If
sheet -like and cracks if disturbed, then it
is natural.

Natural sheen
Natural Sheen vs. Synthetic Sheen
Synthetic sheen
Foam and Suds
Low severity, naturally occurring suds
High severity suds
Sewage fungus photo courtesty of Wayne County Illicit Discharge Elimination Program, natural
sheen image courtesy of NOAA's National ocean Service} synthetic sheen photo courtesy of
Jane Thomas, IAN Image Library (ian.umces.eduf imagelibrary/), all others courtesy of the Center
for Watershed Protection.

Outfall Condition
The physical condition of an outfall can provide strong clues about the history of
discharges passing through it. Over time, intermittent discharges can cause outfall
damage or leave behind remnants in the form of deposits or stains which can help an
inspector determine what type of discharge traveled through the area. Field inspectors
should document that a deposit or stain is present even if there is no dry weather
discharge observed.
Condition Things to Consider
Structural • Cracked, deteriorated concrete or peeling surface
Damage paint at an outfall usually indicates the presence of
contaminated discharges
• Contaminants causing this type of damage are
usually very acidic or basic (alkaline) and originate
from industrial processes
Deposits and
Stains
(Residues)
Outfall Classifications
• Staining may be any color but is characteristically
different from the outfall
• Residues can contain fragments of floatable
substances
• Gray -white deposits can be from illegal dumping of
concrete truck washouts
• Crystalline powder can indicate the discharge of
fertilizer wastes
The Center for Watershed Protection (CWP) developed outfall classifications
categorizing outfalls based on their characteristics and likelihood to pose a problem.
Use these classifications to record the state of the outfall at the time of inspection.
Classification
Description
1 Obvious
Flowing outfall where there is an illicit
discharge that does not require sample
collection for confirmation; exhibits
physical indicators and field -measured
chemical indicators
2 Suspect
Flowing outfall with high severity on one
or more physical indicators
3 Potential
Flowing or non -flowing outfall with
presence of two or more physical
indicators
4 Unlikely
Non -flowing outfall with no physical
indicators of an illicit discharge

Biological Indicators
Biological indicators include things that live and grow. The biological indicators that
should be investigated during a field inspection are: the condition of the surrounding
vegetation, algae growth, amount and types of bacteria, fish kills, and the presence or
absence of certain aquatic organisms.
Biological Things to Consider
Indicators
Vegetation Seasonal and recent weather conditions should be
considered to accurately determine if the vegetation
near an outfall is normal or abnormal. Increased or
inhibited plant growth, as well as dead and decaying
plants, near stormwater outfalls is often a sign of
pollution.
Algae
An overabundance of nutrients can cause elevated
plant growth or algae blooms. During an algae bloom,
the water body typically becomes a pea-green color;
however, the color depends on the dominant species of
algae present.
Bacteria
The amount and types of bacteria present can be
extremely significant. Bacteria can be associated with
inadequately treated sewage, sanitary sewer overflows,
improperly managed waste from livestock, failing septic
systems, and pets and wildlife (e.g., birds nesting
under a bridge). Although some types of bacteria are
visible to the naked eye — such as sewage fungus or
natural sheen, counts for indicators like E. coli are done
in the laboratory.
Fish Kills
Fish kills can be caused by a wide variety of factors
including a decrease in dissolved oxygen, infectious
disease, a rise in water temperature, toxic algae
blooms, parasites, and bacterial or viral infections. The
loss of a single fish is typically a natural occurrence
and is not usually a cause for concern.
Presence or
The presence or absence of aquatic life in and around
Absence of
a water body can be an indicator of the health of the
Aquatic Life
water body. Field inspectors should document whether
or not they observe aquatic life at the time of
inspection.
When conditions warrant (see flow chart on page 2), Tier I parameter testing should be a
regular part of a field inspection. Parameter measurements at or above the recommended
levels should be investigated further. Once an illicit discharge has been found, the next
step is to trace and remove the source of the discharge.

Storm Drain Network Investigations
This technique involves:
• Inspecting manholes in a storm drain system by using chemical and physical
indicators to isolate discharges to specific segments of the network.
• Identifying where to inspect the network and what indicators to use to determine
if a manhole is clean or contaminated.
• Developing a strategic plan for inspecting the pipe network.
Option 1:
Move up the trunk
Option 2:
Split the storm drain
network
❑ ❑Work progressively up the
❑ ❑ Split trunk into equal
trunk from the outfall and test
segments and test manholes
manholes along the way
at strategic junction in the
❑ ❑Start with the manhole
storm drain system
closest to the outfall
❑ ❑ Particularly suited to
❑ ❑Goal is to isolate discharge
larger, more complex
between two storm drain
drainage areas since it can
manholes
limit total number of
manholes to inspect
There are three basic approaches to on -site investigations that will help determine the
actual source of an illicit discharge: dye, video, and smoke testing. Note: these
techniques should be used when conducting a follow-up investigation once an illicit
discharge has been found. Refer to the CWP IDDE manual for more detailed
information on how to use these techniques. Before performing any dye or smoke
testing, make sure to contact other city departments, spill response agencies, and
downstream municipalities to let them know when and where these activities will take
place.

Tier 1 Chemical Parameters
Tier I Parameters Potential Sources Level of Concern
Ammonia -Nitrogen Microbial decomposition t.o mg/L
of animal and plant
proteins,
sanitary wastewater, raw
or partially -treated
sewage,
petroleum refining and
chemical industries,
synthetic fibers and dyes,
drugs, pesticides, and
fertilizer
Chlorine Used to indicate inflow 0.2 mg/L
from potable water
sources; used as
disinfectant in water and
wastewater treatment
processes
Conductivity
Used to measure total
1500 PS/cm
dissolved solids (TDS);
TDS can increase as a
result of wastewater
discharges, irrigation,
and overuse of fertilizers
Copper
Can indicate waste from
0.2 mg/L
manufacture of electrical
components, coins,
bronze, and brass
products
Detergent
Can indicate a discharge
0.2 mg/L
from wash water or
laundry
pH
Extreme pH values (low
Below 6.o su or
or high) may indicate
above g.o su
commercial or industrial
flows