v>EPA
United States
Environmental Protection
Agency
Office of Water
Washington, D.C.
EPA 832-F-99-024
September 1999
Storm Water
Management Fact Sheet
Storm Water Contamination Assessment
DESCRIPTION
A Storm Water Contamination Assessment (SWC A)
reviews a facility and/or a site to find materials or
practices that may contaminate storm water. This
assessment helps target the most important pollutant
sources for correction or prevention.
A SWCA program is closely related to other BMPs,
such as materials inventory, non-storm water
discharges, record keeping, and visual inspections.
APPLICABILITY
An SWCA program is applicable to any industrial
facility which contains areas, activities, or materials
which may contribute pollutants to storm water
runoff from the total site. An assessment for storm
water purposes may also be applicable in situations
where a formal site assessment for hazardous waste
purposes is being performed.
ADVANTAGES AND DISADVANTAGES
A comprehensive SWCA program can eliminate
pollution sources that can impair receiving water
quality. However, there are limitations associated
with a contamination assessment program,
including:
• Assessments need to be performed by
qualified personnel.
• Assessments are useful only if there is
corporate commitment to reduce any
contamination sources discovered.
• Assessments need to be periodically
updated.
KEY PROGRAM COMPONENTS
A SWCA program should include:
• Assessing potential pollutant sources and
associated high risk activities such as
loading and unloading operations, outdoor
storage activities, outdoor manufacturing or
processing activities, dust- or particulate-
generating activities, and on-site waste
disposal practices.
• Determining which of these sources pose the
greatest risks of polluting storm water
runoff from the site.
• Selecting other cost-effective BMPs to
prevent or control pollution from the high-
risk sources at the site.
IMPLEMENTATION
In addition to identifying problems within the storm
sewer system, it is even more important to prevent
problems from developing at all, and to provide an
environment in which future problems can be
avoided. Thus, an effective storm water assessment
program should include follow-up activities
including:
• Educating the public about the
consequences of misusing storm sewers.
• Pretreating industrial storm water or
disconnecting commercial and industrial
storm water entries into the storm drainage
system.
• Tackling the problem of widespread septic
system failure.
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• Disconnecting direct sanitary sewerage
connections from the storm sewer system.
• Rehabilitating storm or sanitary sewers to
abate infiltration by contaminated water.
• Developing zoning and other ordinances.
In some communities that are assumed to have
separate sanitary and storm sewer systems, the
storm sewer system may actually act as a combined
sewer system. In these cases, the community may
consider designating the storm sewer system a
combined sewer and treating the discharge.
A SWCA program and the related correction
program need to be periodically updated, based on
their effectiveness and on the introduction of new
raw materials or changes in processes at the site.
Because the results and performance of a SWCA
program depend on the severity of the risks
uncovered and the corrective actions taken, it is
difficult to quantify the water quality benefits of a
risk assessment program. Clearly, however, a
program that identifies potential pollution sources
and corrects them will improve water quality.
COSTS
3 U.S. EPA, Pre-print, 1992. Storm Water
Management for Industrial Activities:
Developing Pollution Prevention Plans and
Best Management Practices. EPA 832-R-
92-006.
ADDITIONAL INFORMATION
Center for Watershed Protection
Tom Schueler
8391 Main Street
Ellicott City, MD 21043
Northern Virginia Planning District Commission
David Bulova
7535 Little River Turnpike, Suite 100
Annandale, VA 22003
Oklahoma Department of Environmental Quality
Don Mooney
Water Quality Division, Storm Water Unit
P.O. Box 1677
Oklahoma City, OK 73101-1677
Southeastern Wisconsin Regional Planning
Commission
Bob Biebel
916 N. East Avenue, P.O. Box 1607
Waukesha, WI 53187
Costs for the initial assessment may be high.
However, by pinpointing high risk areas, a risk
assessment may reduce overall costs associated with
a complete BMP implementation program. The
costs associated with a risk assessment program for
storm water are small when compared with those of
an overall hazardous waste site assessment.
REFERENCES
1. Pitt, R., D. Barbe, D. Adrian, and R. Field,
1992. Investigation of Inappropriate
Pollutant Entries into Storm Drainage
System - A User's Guide, U.S. EPA,
Edison, New Jersey.
2. U.S. EPA, 1981. NPDESBest
Management Practices Guidance
Document.
United States Postal Service
Charles Vidich
6 Griffin Road North
Windsor, CT 06006-7030
The mention of trade names or commercial products
does not constitute endorsement or recommendation
for the use by the U.S. Environmental Protection
Agency.
For more information contact:
Municipal Technology Branch
U.S. EPA
Mail Code 4204
401 M St., S.W.
Washington, D.C., 20460
MTB
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