EPA/600/A-92/061
NON-STORMWATER DISCHARGES INTO
STORM DRAINAGE SYSTEMS
Robert E. Pitt, Assistant Professor, Department of Civil Engineering, University
of Alabama at Birmingham, Birmingham, Alabama 35294.
Richard Field, Chief, Storm and Combined Sewer Pollution Control Program, U.S.
Environmental Protection Agency, Edison, New Jersey 08837.
ABSTRACT: This paper summarizes the first phase of an EPA sponsored research
project to develop a manual of practice to investigate non-stormwater discharges
of polluted waters into storm drainage systems. 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 with many stormwater
control programs. These dry-weather flows may originate from many sources, the
most important sources may include sanitary sewage or industrial and commercial
discharge cross-connections, failing septic tank systems in storm sewered areas,
and vehicle maintenance activities. After the outfalls are identified that are
affected by polluted dry-weather flows, additional survey activities are needed
to locate and correct their sources.
KEYWORDS: Non-stormwater discharges, cross-connections; stormwater; dry-weather
flow.
Introduction
This paper is a preliminary summary of the first phase of a current EPA
research project to:
o develop investigative techniques to assist local
governments in identifying the magnitude and
sources of non-stormwater discharges to their
storm drainage systems; and
o present case studies of techniques used by
selected municipalities in identifying these non-
stormwater discharges.
Discharges from storm drainage outfalls can be a combination of dry-weather
base flows; stormwater runoff; snowmelt water; intermittent discharges of debris,
wash-waters, and other waste materials into storm drains; and the relatively
continuous discharges of sanitary and industrial cross-connected wastes. These
discharges include stormwater that contains the washoff of pollutants from all
land surfaces during rains,
including washoff of pollutants from areas such as industrial material and waste

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storage areas, gas station service areas, parking lots, and other industrial and
commercial areas, etc. Therefore, the quality of urban runoff can vary greatly
with time (dry versus wet-weather, cold versus warm weather, etc.) and location.
The discharge of sanitary and industrial wastes into storm drainage
(non-stormwater discharges) can lead to serious water pollution problems. In many
cases, storm drain discharges are badly polluted by stormwater alone, without the
additional pollutant loadings associated with sanitary or industrial
non-stormwater discharges. The addition of sanitary wastes increases the
concentrations of organic solids and nutrients, and increases the potential of
pathogenic microorganisms in the runoff. Industrial wastes can be highly
variable, but can substantially increase the concentrations of many filterable
heavy metals in runoff, as an example. In many cases, annual discharge loadings
from stormwater outfalls can be greatly affected by dry-weather discharges.1,2,3
Dry-weather and wet-weather urban runoff flows have been monitored during
many urban runoff studies that have found that discharges observed at outfalls
during dry weather were significantly different from wet-weather runoff. Warm and
cold weather runoff was also contrasted during some studies and was also found
to be quite different. During the Castro Valley, California, Nationwide Urban
Runoff Program (NURP) study, Pitt and Shawley found that the dry-weather flows
were very hard and had very few nonfilterable pollutants, while the stormwater
runoff was quite soft and had substantial nonfilterable metals.1 The dry-weather
flows were found to contribute substantial quantities of many pollutants, even
though the concentrations were not high. The long duration of baseflows in many
areas of North America (about 95 percent of the time) off-set their lower
concentrations and lower flow rates as compared to wet-weather (stormwater)
flows.
The Bellevue, Washington, NURP project summarized the reported incidents
of intermittent discharges and dumpings of pollutants into the local storm
drainage system.4 During a three year period of time, about 50 citizen contacts
were made to the Bellevue Storm and Surface Water Utility District concerning
water quality problems. About 25 percent of the complaints concerned oil being
discharged into catchbasins. Another important category of complaints was for
aesthetic problems, such as turbid or colored water in the creeks. Various
industrial and commercial discharges into the storm drainage system were
detected. Concrete wastes flushed from concrete trucks at urban job sites were
a frequently occurring problem. Cleaning establishment discharges into creeks
were also a common problem. Vehicle accidents also caused spills of gasoline,
diesel fuel, hydraulic fluids, and lawn care chemicals from damaged trucks that
commonly flowed into the storm drain inlets. Pitt also monitored both dry- and
wet-weather discharges from stormwater outfalls in Bellevue and found significant
pollutant yield contributions associated with dry-weather discharges from
residential areas.2
Dry-weather flows in a monitored Toronto residential area were found to
have high pesticide concentrations, while a monitored industrial area had
dry-weather flows that had high concentrations of organic and metallic
toxicants.3 This Toronto project also found substantial differences in warm and
cold weather dry- and wet-weather runoff. More than 50 percent of the annual
discharges of water volume, total residue, chlorides, and bacteria, from the

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monitored Industrial, residential, and commercial areas, were associated with
dry-weather discharges. Substantial metal discharges, especially from the
industrial area, were also found to be associated with dry-weather discharges.
Gartner Lee and Associates, Ltd. conducted an extensive survey of
dry-weather storm drainage in the Humber River watershed (Toronto) 1n an attempt
to identify the most significant urban runoff pollutant sources.5 About 625
outfalls were sampled two times during dry-weather, with analyses conducted for
many pollutants, including organlcs, solids, nutrients, metals, phenols, and
bacteria. About 1/3 of the outfalls were discharging at rates greater than 1
L/sec. The dry-weather flows were found to contribute significant loadings of
nutrients, phenols, and metals, compared to upstream conditions. About 10 percent
of the outfalls were considered significant pollutant sources. Further
investigations identified many industrial and sanitary sewage non-stornwater
discharges into the storm drainage. An apartment building with the sanitary
drains from eight units illegally connected to the storm drainage system was
typical of the problems found. Other problem areas were found in industrial
areas, including liquid dripping from animal hides stored in tannery yards and
washdowns of storage yards at meat packing plants.
Methodology
A specific objective of this project is to identify the most promising
techniques to identify, quantify, and locate non-stormwater discharges of
sanitary and industrial wastes entering storm drainage systems.
As noted above, non-stormwater discharges can take multiple forms. Many
non-stormwater discharge problems are associated with Intermittent discharges.
These intermittent discharges occur during wet weather as runoff from storage
areas, or as illegal dumping or washing operations that occur during dry or wet
weather. Other non-stormwater discharge problems are caused by continuous
connections that can occur during both wet and dry weather. These can be
associated with "non-contact" cooling water discharges (which frequently contain
a variety of chemicals, including algicides and corrosion inhibitors), other
industrial wastewater connections, and sanitary sewage waste connections, for
example.
This project is identifying procedures that can be used to identify the
significance and type of either intermittent or continuous discharges occurring
during dry weather. The pollutant contributions associated with non-stormwater
discharges can be distinguished by unique characteristics based on water types
and typical pollutants. As an example, the major water types (major 1ons) of the
flow components could vary substantially: the water supply source could be either
groundwater or surface water (this water type would represent many of the
wastewater types), while an uncontaminated baseflow source could be from local
springs, groundwater, or from regional surface flows. Knowing the specific water
source for each flow component could enable the relative mixture of
uncontaminated baseflow and the other non-stormwater discharges to be calculated.

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Potential Dry-weather Discharge Sources
The following list summarizes the potential contaminated residential area
non-stornwater discharge sources being evaluated:
Sewage sources:
o raw sewage from directly connected or leaky
sanitary sewerage
o septage from improperly operating septic tank
systems
Household automobile maintenance:
o car washing runoff
o radiator flushing
o engine de-greasing
o improper oil disposal
Residential irrigation sources:
o over-watering runoff
o direct spraying of impervious surfaces
Roadway and other accidents:
o fuel spills
o spills of truck contents
o pipeline spi 1 Is
Other:
o washing of ready-mix trucks
o laundry wastes
o improper disposal of other household toxic
substances
o dewatering of construction sites
o sump pump discharges
o contaminated surface and groundwaters
Commercial and industrial dry-weather discharges are being considered in
a separate study conducted by Triad Engineering of Milwaukee. The results of the
Triad study are being incorporated into the complete EPA manual. The commercial
and industrial approach is stressing differentiating industrial categories used
in the industrial discharge permit program.
The natural baseflow raw water source flows, along with the sewage related
sources and many industrial sources, would be relatively continuous in flow
duration. The other sources would be intermittent. As a drainage area increases
in size, however, the probability also increases that dry-weather discharges
associated with individual intermittent activities would appear continuous at the
outfall. Most of the studies referenced previously found flows at the monitored
outfalls most of the time during dry weather, even though the flows were very low
at times. The quality of the flows also changed dramatically at different times
of the day for the monitored Toronto industrial outfall.3 Some trends were also
noted for dry-weather outfall flows for different times of the year.

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Th1s study is identifying unique physical, biological, or chemical
characteristics that would distinguish the different flow sources.
Monitoring Approach
The purpose of the monitoring procedures is to separate the outfalls into
three general categories (with a known level of confidence) to Identify which
outfalls need further analyses and investigations. These categories are: (1)
pathogenic or toxic pollutant sources, (2) nuisance and aquatic life threatening
pollutant sources, and (3) unpolluted water sources. The pathogenic and toxic
pollutant source category would be considered the most severe and could cause
disease upon water contact or consumption and significant Impacts on receiving
water organisms. They may also cause significant water treatment problems for
downstream consumers, especially for soluble metal and organic toxicants. These
pollutants may originate from sanitary, commercial, and industrial non-stornwater
discharges. Other residential area sources (besides sanitary wastewater), such
as inappropriate household toxicant disposal, automobile engine de-greas1ng,
vehicle accident clean-up, and irrigation runoff from landscaped areas
excessively treated with chemicals (fertilizers and pesticides) may also be
considered 1n this most critical category.
Nuisance and aquatic life threatening pollutant sources can originate from
residential areas and may include laundry wastes, landscaping irrigation runoff,
automobile washing, construction site dewatering, and washing of ready-mix
trucks. These pollutants can cause excessive algal growths, tastes and odors 1n
downstream water supplies, and highly colored, turbid or odorous waters.
Clean water discharged through stormwater outfalls can originate from
natural springs feeding urban creeks that have been converted to storm drains,
infiltrating groundwater, infiltrating domestic water from water line leaks, etc.
The proposed monitoring approach is separated into three phases:
o initial mapping effort
o initial field surveys
o confirmatory chemical analyses.
These three initial phases will be followed by detailed storm drainage and site
investigations to identify specific pollutant contributors and control options.
An important requirement of the methodology is that an initial field
screening effort would require minimal effort and would have little chance of
missing a seriously contaminated outfall. This screening program would then be
followed by a more in-depth analysis to more accurately determine the
significance and source of the dry-weather pollutant discharges.
Mapping. The most important step in a non-stormwater discharge problem
investigation is in preparing and studying drainage and land use maps. In
addition to mapping, aerial photographs and general site investigations may be
very useful. The most important objective of the mapping activities would be to
identify the locations of all of the stornwater outfalls. Finding the outfalls

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is not trivial. In the case studies examined, repeated trips typically uncovered
additional outfalls that could not be located during earlier excursions. In
Toronto, for example, most outfalls were located during the first field trip, but
two more trips were needed before all of the outfalls were located.5 Similarly,
additional outfalls were periodically found that were not identified on the city
storm drainage maps. It is very difficult for communities to maintain up-to-date
mapping of drainage facilities.
Another important objective of the Initial mapping activities is to outline
the drainage areas discharging to the outfalls. These drainage maps should
identify the predevelopment streams that may have been converted to storm drains
(indicating the likelihood of natural uncontaminated baseflows) and the current
and past land uses. Specific land use categories to be Indicated should include
commercial and industrial land uses, plus other activities that may contribute
runoff problems (such as land fills). Any industrial activities having
significant potential of contributing flows to the storm drainage system, as
indicated by Triad's analyses, need to be specifically identified and located.
Further drainage area investigations would be conducted after the outfall
studies have indicated dry-weather discharge problems. These would include
drainage system and industrial and commercial site studies (such as dye and smoke
studies) to locate specific non-stormwater discharges. Additionally, aerial
photography can be very useful during later phases of non-stormwater discharge
control projects. As an example, aerial photography can be very useful in
Identifying areas having failing septic systems located in residential areas
served by storm drainage systems. Aerial photography can also be used to identify
continuous discharges to surface drainages, such as sump discharges, and to
identify storage areas that may be contributing significant amounts of pollutants
during rains.
Initial field surveys. The initial field surveys are to be used as a
screening effort: to identify the outfalls needing more detailed investigations
which would identify pollutant sources and control options. These initial surveys
would include physical and limited chemical evaluations of outfall conditions and
would be conducted to minimize "false negatives" (outfalls actually having
important discharges, but falsely classified as not needing further
investigation).
Different flow and pollutant characteristics of the potential discharge
sources can be used to identify and quantify non-stormwater discharge problems.
The initial surveys to obtain this key information should be repeated at all
outfalls over several seasons. Many of the dry-weather discharges are
intermittent and may not be noted during any one investigation. Various physical
characteristics near the outfall can provide evidence that inappropriate
discharges periodically occur. However, repeated trips to the outfalls
significantly increase the probability of Identifying problem outfalls.
It is difficult to develop a procedure that will separate the outfalls into
clear "problem" and "no problem" categories. In some of the case studies
investigated, only correcting problems at the most critical outfalls resulted in
insufficient receiving water quality improvements. It may be important to
eventually correct all non-stormwater discharge problems throughout a city, not

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just the most severe problems. This screening procedure should therefore be
considered as just an Initial effort that needs to be followed-up with more
detailed confirmatory investigations at the outfalls and receiving water
monitoring to document improvements after different stages of the control
program.
Candidate parameters. Many different analytical methods are being evaluated
as part of this project. The initial screening effort should Include the
following:
o placement of outfall identification number;
o outfall discharge flow estimate;
o floatables, color, oil sheen, and odor
characteristics of water;
o other outfall area characteristics, such as
stains, debris, damage to concrete, corrosion,
unusual plant growth, or absence of plants;
o water temperature;
o conductivity;
o fluoride concentration;
o ammonia and/or potassium concentrations; and
o surfactant concentration.
These characteristics can be relatively easy to obtain at the outfall
location, depending on the needed detection limits for the chemical analyses and
potential interferences. The selection of the procedures to use to obtain the
tracer concentrations will depend on many conditions, most notably the expected
tracer concentrations in the uncontaminated base flows and 1n the potential
non-stormwater source flows, along with the needed probabilities of detection at
the minimum contamination level. Other factors affecting procedure selection
include ease of use, analytical interferences, cost of equipment, training
requirements, and time requirements to conduct the analyses.
Simple outfall estimates of discharge, and noting the presence of oil
sheens, floatables, color, odors, etc. will probably be the most useful
indicators of outfall problems. These observations will need to be repeated
several times, especially if non-continuous discharges are likely. The presence
of stains and structural damage will greatly assist in identifying significant
non-continuous discharges.
Notably absent from the above list are pH and dissolved oxygen. These have
been included in several previous non-stormwater discharge studies, but with
limited value. These two parameters have not been found to be extremely useful
in identifying or categorizing pollutant sources. However, in areas having known
industrial sources, pH may be an important parameter that would have to be added
to this list.
Specific conductance and temperature can be quickly and easily measured
using a dual dedicated meter. Water color can be quantified using a comparative
colorimetric meter or spectrophotometer in the field.

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Fluorides can be detected using a variety of methods 1n the field.
Including field colorlmetrlc kits having detection limits of less than 0.15 mg/L.
This detection limit may not be sufficient to detect low dilutions of
contaminants with adequate precision. Dedicated specific 1on meters for fluorides
are available having very low detection limits (2 ug/L) that would be quite
capable of detecting very small dilutions. Neither of these methods are "direct
reading" and require some time at the site to conduct the analysis and/or
calibrate the meter.
Ammonium forms of nitrogen can be measured 1n the field using Indicator
paper, with detection limits of about 10 mg/L. Field colorlmetrlc kits having
detection limits of about 0.1 mg/L are available for total ammonia. Ion selective
electrodes can be used 1n the field, with detection limits of about 0.01 mg/L for
ammonia. Only the indicator paper method 1s a direct measurement procedure, but
it probably does not have a low enough detection limit to permit the detection
of low dilutions of non-stornwater contaminants. The other methods require some
sample preparation, but would be much more useful.
Potassium can be measured in the field using ion selective electrodes
having detection limits as low as 0.01 mg/L. Portable spectrophotometers can also
be used, with detection limits of about 0.1 mg/L. Either of these methods can be
useful in a non-stormwater discharge study.
Detergents (or surfactants) can be detected 1n the field using a
comparative colorimetrlc method (having a detection limit of 50 ug/L) or with a
recently developed auto titration method having very few interferences and much
lower detection limits.
In addition, the following optional characteristics may also be obtained
at each outfall, depending on probable pollutant sources:
o hardness;
o toxicity screening; and
o specific metals.
Hardness can be easily determined in the field using field titrimetrlc kits or
even indicator papers, with varying sensitivities and interferences. Toxicity
screening tests require laboratory analyses and some can be conducted in several
hours. The toxicity tests would be useful in areas known to have commercial or
industrial activities. Some individual metals (especially copper and chromium)
could also be used in areas having these land uses. In most cases, 1t will
probably be necessary to conduct a variety of carefully selected tests because
of the large number of potential pollutant sources that probably occur 1n most
drainage areas.
This scheme should allow an efficient determination of the general category
(toxic/pathogenic, nuisance, or clean) of the water being discharged. In many
cases, fluorides can be used to separate untreated water from treated water
sources. Untreated water sources may include discharges from natural waters or
untreated industrial waters. If the treated water has no fluoride added, or if
the natural water has fluoride concentrations close to treated water fluoride
concentrations, then fluoride may not be an appropriate Indicator. Hardness can

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be used as an indicator if the clean water source is likely groundwater, while
the treated water source is from surface supplies. Specific major ions could also
be used to separate groundwater and surface water sources. Specific conductance
may also serve as a rough indicator of major water source.
Water from treated water supplies (that test positive for fluorides, or
other suitable tracer) can be relatively uncontaminated (domestic water line
leakage or irrigation runoff), or it may be heavily contaminated. In areas having
no industrial or commercial sources, sanitary wastewater is probably the most
important non-stormwater source. Surfactants may be useful in determining the
presence of sanitary wastewaters. However, surfactants in water from treated
water sources could indicate sanitary wastewaters, laundry wastes, car washing
water, or other waters having detergents. Fabric whiteners (as measured by
fluorescence using a fluorimeter in the laboratory or in the field) may also be
a useful test for laundry and sanitary wastes.
If the surfactants were not present, then the treated water could be
relatively uncontaminated (such as from domestic water line leaks or irrigation
runoff), or it may be from rinsing ready-mix trucks or other rinsing activities
(such as accident scenes). Sanitary wastewater would have the most consistent
characteristics (volume and characteristic) compared to most of the other
potential sources. Ammonia (or ammonium) nitrogen and potassium have been studied
in several previous studies as an indicator of sanitary wastewaters. If the
surfactant concentrations were high, but the ammonia and potassium concentrations
were low, then the contamination is likely from laundry water. If they were all
high, then sanitary wastewater is the likely source. Obviously, odor and other
physical appearances (such as turbidity, foaming, color, and temperature) would
also be very useful in separating major sanitary wastewater flows from rinse
water or laundry water sources.
Several confirmatory outfall analyses could be conducted to verify the more
significant sources of non-stormwater discharges. These analyses require highly
trained personnel and specialized equipment that would not be available in most
laboratories. It may not be feasible to analyze samples from each of several
hundreds of outfalls several times a year for these materials. These analyses can
be very useful to check for false negatives and for more specific results on a
random basis. These confirmatory analyses may include:
o trihalomethanes
o specific bacteria
o coprostanol
Trihalomethanes (THMs) are formed when chlorine reacts with certain natural
organics present in waters. The detection of these compounds in groundwaters has
been used as a positive indication of treated city water leakage.6 Chloroform
and dichlorobromethane are the THMs most frequently used because of their very
low detection limits and specific indicators of treated domestic water.

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Bacteria are usually poor indicators of the source of cross-connection
water. Past use of fecal strep, to fecal conform ratios to indicate human versus
nonhuman bacteria sources in mixed and old wastewaters (such as most nonpoint
waters) has not been very successful. There may be some value in investigating
specific bacteria types, such as fecal strep, biotypes, but much care needs to
be taken 1n the analysis and interpretation of the results. A more certain
indicator of human wastes may be the use of certain human-specific molecular
markers, specifically the linear alkylbenzenes and fecal sterols, such as
coprostanol and epicoprostanol.7
Detailed outfall analyses. After the initial outfall surveys indicate the
presence of serious contamination, additional pollutants associated with local
commercial and industrial activities need to be monitored. This monitoring will
assist in identifying the classes of commercial or industrial activities
responsible for the contamination.
Watershed analyses to locate specific sources. In order to identify the
specific contaminant sources in the drainage system, further detailed analyses
are needed. These may include:
o drainage system surveys (tests for specific pollutants, visual
inspections, and smoke and dye tests)
o in-depth watershed evaluation (Including aerial photographs)
o industrial and commercial site studies
Conclusions
Many urban runoff projects have found that dry-weather discharges from
stormwater outfalls can contribute significant pollutant loadings. Ignoring these
loadings can lead to improper conclusions concerning stormwater control
requirements.
Municipalities that have recognized the importance of dry-weather flows
have investigated their sources using various methods. Unfortunately, most
municipalities have very large numbers of outfalls and an efficient method is
needed to separate the outfalls creating the most severe problems. This project
is examining three categories of outfalls: pathogenic/toxicant, nuisance and
aquatic life threatening, and clean water. The most important category 1s for
outfalls contributing pathogens or toxicants. These are most likely originating
from sanitary wastewater or industrial non-stormwater discharges. An initial
screening analysis at all outfalls should have a high probability of identifying
all outfalls in this category.
The first step of this procedure is an extensive mapping effort to identify
the locations of all outfalls for sampling and to outline the drainage areas
contributing to each outfall. The screening analyses at the outfalls include
several visual measures (color, turbidity, oil sheens, floatables, etc.) along
with measurements for fluorides and surfactants. Fluorides indicate if the water
originated as treated domestic water (instead of infiltrating untreated

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groundwater). This may Indicate sanitary sewage non-stormwater discharges or
other waste waters. Surfactants can help in identifying sanitary sewage
connections, in contrast to landscaping irrigation runoff or rinse waters, or
industrial waters. The drainage area maps need to be studied to determine the
presence of potential industrial or commercial cross-connection sources.
More sophisticated analyses are available to confirm the potential sources,
but they most likely cannot be employed for all outfall samples because of the
required highly skilled analysts and expensive equipment.
Future project phases will evaluate these outfall procedures in test
conditions and will result in refinements to the manual of practice. Procedures
to identify and correct specific non-stormwater discharges will also be
summarized in these future project phases.
Acknowledgements
This project is being carried out under contract with the U.S.
Environmental Protection Agency. The opinions expressed in this paper are the
opinions of the authors alone, and are not official policies of the U.S.
Environmental Protection Agency.
References
1.	Pitt, R. and G. Shawley. A Demonstration of Nonpoint Pollution Management
on Castro Valley Creek. Alameda County Flood Control District (Hayward,
California) and the U.S. Environmental Protection Agency, Washington, D.
C., June 1982.
2.	Pitt, R. Characterization, Sources, and Control of Urban Runoff by Street
and Sewerage Cleaning. Contract No. R-80597012, U.S. Environmental
Protection Agency, Office of Research and Development, Cincinnati, Ohio,
1984.
3.	Pitt, R. and J. McLean. Humber River Pilot Watershed Project, prepared for
the Ontario Ministry of the Environment, 1986.
4.	Pitt, R. and P. Bissonnette. Bellevue Urban Runoff Program, Summary
Report. U.S. Environmental Protection Agency and the Storm and Surface
Water Utility, Bellevue, Washington, November 1984.

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5.	GLA (Gartner Lee and Associates, Ltd.)- Toronto Area Watershed Management
Strategy Study, Technical Report #1, Humber River and Tributary
Dry-weather Outfall Study. Ontario Ministry of the Environment. Toronto,
Ontario, November 1983.
6.	Hargeshelmer, E.E. "Identifying Water Main Leaks with Trihalomethane
Tracers." Journal American Water Works Association, pp. 71-75. November
1985.
7.	Eganhouse, R.P., D.P. Olaguer, B.R. Gould and C.S. Phinney. "Use of
Molecular Markers for the Detection of Municipal Sewage Sludge at Sea."
Marine Environmental Research. Volume 25, No.l. pp. 1-22. 1988.

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TECHNICAL REPORT DATA
before eortpUr
1. REPORT NO.
EPA/6G0/A-92/061
4. title and subtitle
5 REPORT DATE
Non-Stormwater Discharges Into Storm Drainage Systems ^.performing organization code
7. AUTMORIS;
18 PERFORMING ORGANIZATION REPORT NO
^Robert Pitt and Richard Field
9| PERFORMING ORGANIZATION NAME ANO ADDRESS	110 PROGRAM ELEMENT NO
.Dept. of Civil Engineering, University of Alabama at j
2 Birmingham, AL 35294	¦ 11 contract/grant no
US Environmental Protection Agency, Edison, NJ 08837
68-C9-0033
12 SPONSORING AGENCv NAME and ADDRESS
Risk Reduction Engineering Laboratory
Office of Research and Development
US Environmental Protection Agency
Cincinnati, OH 45268
'13 Tvpe op REPORT AND PERIOD COVERED
¦ Published Paper	
14 SPONSORING AGENCY COOE
EPA/600/14
^.supplementary notes Project Officer = Richard Field (FTS) 340-6674 (COM) 321-6674
Specialty Conference Proceedings of Control of Combined Sewer Overflows, Bostian, MA
4/8-11/90
6. ABSTRACT
This paper summarizes the first phase of an EPA sponsored research project to
develop a manual-of-practice to investigate non-stormwater discharges of polluted
waters into storm drainage systems. 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
in receiving water conditions may occur with many stormwater control programs.
These dry-weather flows may originate from many sources, the most important sources
may include sanitary sewage or industrial and commercial discharge cross-connections,
failing septic tank systems in storm sewered areas, and vehicle maintenance
activities. After the outfalls are identified that are affected by polluted dry-
weather flows, additional survey activities are needed to locate and correct
their sources.
17.
KEV WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.IDENTIFIERS/OPEN ENDED TERMS C. COSATI Fldd/Grour
Drainage, *Water pollution, *Surface
water runoff, *Runoff, *Wastewater,
~Sewage, Containments, *Storm sewers
~Combined sewers. Hydrology, Hydraulics,
~Overflows--sewers, *Urban hydrology.
Drainage systems. Water
pollution control, Non-
stormwater discharges,
Cross-connections,
Stormwater, Dry-weather
flow
IB. DISTRIBUTION STATEMENT
Release to Public
19. SECURITY CLASS (ThilRtporti
Unclassified.
21. NO. OP PAGES
13
30. SECURITY CLASS (ThU puft)
Unclassified
22. PRICE
EPA Pmrm UM-1 (B-73)

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